Surface Volume Changes Research Articles

Robust VMAT treatment planning for extremity soft tissue sarcomas.

Volumetric modulated arc therapy (VMAT) is a frequently employed and guideline-recommended radiotherapy (RT) modality for extremity soft tissue sarcomas (eSTS). Prior studies have demonstrated that significant tumor volume changes during treatment result in loss of target volume coverage with highly conformal techniques such as VMAT, but few solutions exist to these issues aside from adaptive replanning. Here, we describe a related but novel phenomenon in which relatively minor changes in surface volume contour (whether due to daily setup uncertainty, edema of peritumoral tissue, or progression or pseudo-progression of tumor volume itself) can result in unexpected subcutaneous hotspots. This phenomenon is of significant clinical concern given the known association between skin dose and major wound complications during preoperative RT for eSTS. By evaluating daily cone-beam CT (CBCT) images from thirteen eSTS patients treated with VMAT RT, we identify daily surface contour changes (range: 2 mm-15 mm, median: 8 mm) which are frequently below conventional adaptive replanning thresholds. When applied under experimental conditions, these external contour changes did not have major impacts on target volume coverage (range: 30.2%-91.2%, mean: 72.5%) but did result in unexpected hotspots of 125.8% on average (range: 110.0%-142.2%) in the subcutaneous tissues. To mitigate this issue, we develop a methodology for VMAT treatment planning using flash PTV and virtual bolus (VB) to produce robust treatment plans that are more resistant to target volume changes, surface contour changes, and setup uncertainties than conventional planning methods. With this methodology, robust plans were equivalent to standard plans at baseline, but, after incorporation of surface volume changes, both maintained target volume coverage (p < 0.001) and prevented development of subcutaneous hotspots (p < 0.001) better than standard plans. As such, this treatment planning methodology may facilitate development of robust VMAT treatment plans that minimize development of subcutaneous hotspots and preserve target volume coverage in the context of routine volumetric changes during preoperative RT.

A biomimetic polymer-clay nanocomposite coating for dendrite-free Zn metal anode

Dendrite growth and side reactions in Zn metal aqueous batteries have limited their practical application. Herein, based on the poly(vinylidene fluoride-hexafluoro propylene) (PVDF-HFP) codoped with poly(ethylene oxide) (PEO) and Zn‐based montmorillonite (Zn-MMT), a biomimetic ant nest porous polymer–clay composite as a protective layer is fabricated on the surface of Zn anode (PC@Zn). The PC coating demonstrates flexibility, high mechanical robustness and high ionic conductivity, simultaneously, which can accommodate the Zn surface volume change and maintain close contact with the Zn anode during the cycling. Furthermore, the PC@Zn with improved hydrophilicity can effectively suppress both Zn dendrites growth and H2 evolution by regulating the homogeneous ion diffusion and uniform Zn deposition. Therefore, the PC@Zn anode presents an ultralong cycle lifespan and reversible Zn stripping/plating for thousands of hours at 0.25, 1, and 5 mA cm−2 with high Coulombic efficiency. A full cell PC@Zn//MgVO demonstrates a high capacity (146.2 mAhg-1) at 5 A g−1 and high capacity retention of 95.5% after 3000 cycles. Based on the concept of biomimetics, this work gives inspiration for designing artificial coating layers for ultrastable dendrite-free aqueous metal batteries.

Precision in 3-Dimensional Surface Imaging of the Face: A Handheld Scanner Comparison Performed in a Cadaveric Model

Handheld 3-dimensional surface imaging (3DSI) devices of various precision are becoming more versatile in their applications and more widely accepted by clinicians for documentation. The authors sought to compare the precision of facial volumetric change measurements of 3 3DSI devices in the cadaveric model: Eva (Artec 3D Inc., Luxembourg), Sense (3D Systems, Rock Hill, SC), and iSense (3D Systems, Rock Hill, SC). A total of 336 scanning and analysis procedures were carried out in 4 cephalic specimens (mean age, 77.25 ± 24.3 years; mean BMI, 21.76 ± 6.6 kg/m2). Two superficial and 2 supraperiosteal regions of interest were injected with 0.5-cc aliquots and subsequently scanned using the 3 different scanners. Correlation coefficients between the injected and measured volume were computed. The correlation coefficient for the Eva scanner was for subcutaneous regions of interest rp = 0.935 and for the supraperiosteal regions of interest rp = 0.966, compared with rp = 0.760 and rp = 0.364 (superficial vs supraperiosteal) for the Sense and rp = 0.694 and rp = 0.382 (superficial vs supraperiosteal) for the iSense scanner. 3DSI devices are capable of measuring surface volume changes of the face at a level of 0.5-cc surface volume change and can thus be regarded as useful tools in the preinterventional, intrainterventional, and postinterventional phases of a treatment. One of the 3 evaluated scanners provided very high correlation coefficients between the injected and the measured volume (Eva), whereas the other evaluated 3DSI devices provided moderate (Sense) and low (iSense) coefficients.

Surface potential behaviors of UV treated of Ag anode for high-performance T-OLED by nanotribology

A high reflective bottom anode is essential for high-performance top-emitting organic light emitting devices (OLEDs). Ag has high reflectivity for visible light but its electronic properties are not ideal for anodes of OLEDs. Thus, we investigated the UV treatment effect of Ag film with a thin silver oxide layer at the surface for application of top-emitting OLEDs. In this study, we measured the change of potential difference between Ag film and ITO (indium tin oxide) films, according to UV treatment time and the mechanical properties by KPFM (Kelvin Probe Force Microscope) method and nano-indenter system, respectively. The KPFM and nano-indenter results show that the differences of surface potential and surface volume change according to UV treatment time.

A note on the surface volume change of shallow earthquakes

This note presents an exact analytical formula for determining the magnitude of coseismic surface volume change (δV) of earthquake faults in a half-space. For a Poisson solid, the formula is remarkably simple; δV=Mzz|8µ, where Mzz is one of the moment tensor elements of the source. Maximum δV values derive from dip slip on faults plunging 45°. For these events, surface volume changes of 0.0001 and 4.3 km3 can be expected for magnitude 5 and 8 earthquakes respectively. All of the coseismic surface volume change is recovered in the interseismic period through relaxation of the Earth and rebound of the surface. A useful rule of thumb for estimating the magnitude of vertical rebound in 45° dip slip events is δhp=Δs/24, where Δs is the coseismic slip on the fault.

Validation of three‐dimensional laser scanning for the assessment of facial fat changes

We aimed to evaluate the accuracy of three-dimensional laser scanning as an objective method for detecting facial changes. Facial laser scanning was performed at baseline and repeated after a median of 10 months in 24 HIV-infected patients, 12 with ongoing lipodystrophy, five with >10% weight loss and seven with >10% weight gain. Surface volume change was estimated using a standardized technique, and compared with change in cheek fat measured by magnetic resonance imaging (MRI). The median laser scanning surface volume changes were -2.1 (range -4.6 to -0.8) mL in the lipoatrophy group, -1.5 (range -6.8 to -1.3) mL in the weight loss group and +3.1 (range -0.2 to +5.4) mL in the weight gain group (the median MRI cheek fat changes were -4.6, -3.7 and +7.0 mL in the three groups, respectively). Laser scanning and MRI measurements were not significantly associated in lipoatrophy patients (r=0.34, P=0.28), but there was a good association in patients who changed weight (r=0.71, P=0.01). Laser scanning detects changes in the appropriate direction, although it underestimates MRI-measured cheek fat changes. Laser scanning may be useful as an objective measure of cheek surface volume changes, but needs further validation in larger clinical cohorts.

Microstructural examination of service exposed coal mill liner material

This study mainly focuses the microstructural characterisation of the service exposed coal liner. These liners are generally referred to as bull ring segments in the bowl mill of coal pulveriser systems. The failed bull ring segment was collected from a coal-fired power plant of Kolaghat thermal plant, West Bengal, India. The crack that has been observed in the middle of the liner was observed under SEM and detailed microstructural studies are made for the liner material. The hardness measurements are made and XRD is carried out to identify the phases present in the sample. The results suggest that the material confirms to high chromium cast iron and microstructural studies reveal that the cracks are mainly due to the heavy service exposed conditions where lumps of coal and silica sand falling on these liners causing severe impact and abrasion conditions. High abrasive studies on the liner material are carried out and it showed that increasing the abrasive size as well as load is responsible for higher wear loss. The results suggest that prolonged exposure to abrasion conditions results in the progressive removal of the matrix material and due to various phase transformations from austenite to martensite introduces surface volume changes and causes the generation of cracks and further lead to failure of the component.

Puzzles on Fermi Surfaces in CeRu2Si2: Bonding Kondo State

Mechanism of the unusual continuous transition in CeRu 2 Si 2 from valence fluctuation regime to Kondo regime, in which the Fermi surface volume changes exactly by one electron, is studied in detail. The transition occurs due to the singlet bonding Kondo band, which becomes sharper and more dispersionless as it approaches the Fermi energy with weakening quasiparticle character and crosses the Fermi energy at the transition. Various anomalous properties are related also with the mixed valence character in the valence fluctuation regime, disappearing in the Kondo regime. An unusual behavior of Hall effect with a large and sharp peak at low temperature, which has been misunderstood as the anomalous Hall effect, is explained from the mechanism that there are two kinds of Fermi surfaces, the first group formed from small holes with weak c - f mixing, showing a little change at the transition, and the second group of large Fermi surfaces with strong c - f mixing changing nearly discontinuously at the transition...

The Fermi surfaces of dilute copper alloys. I. Experiment

The changes in six representative extremal areas of the Fermi surface of copper resulting from alloying with small (<or=200ppm) amounts of aluminum and of nickel have been measured with a high precision de Haas-van Alphen technique. The results, which are accurate to a few per cent, have been fitted to Fourier expansion and phase shift models and the two fits show good agreement with one another. The models indicate that the Fermi surface changes are approximately rigid band like in Cu(Al), but are dominated by the d like character of the solute in Cu(Ni). The Fermi surface volume change is close to -1electron/atom in Cu(Ni), but is some 10% less than +2 electron/atom in Cu(Al).

Very low density lipoproteins: Surface-volume changes during metabolism

Removal of triglycerides from the hydrophobic interior of very low density lipoproteins causes a decrease in volume which must be accompanied by a reduction in hydrophilic surface. Lecithin-cholesterol acyl transferase may be responsible for this surface area reduction.