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Pelvic wall control and toxicity was retrospectively assessed in patients who received individually customised parametrial boost (PMB) for locally advanced cervical cancer with 2D planned external beam radiotherapy. Outcomes of a dose-escalated combined boost were also evaluated.
Materials and methods:
Toxicity and pelvic wall recurrence was evaluated over a median period of 24 months between two groups who received different pelvic wall doses. One group was randomised to receive either intracavitary brachytherapy (ICRT) with an external beam PMB using a customised midline shield, or a dose-escalated combined boost with interstitial brachytherapy (ISBT) and PMB. The comparator group received no PMB.
At 24 months, pelvic wall recurrence occurred in 2/112 and 40/130 with and without PMB, respectively (p < 0·000001). No significant difference in toxicity was noted between boost versus no-boost groups (p = 0·56). Combined ISBT/PMB dose escalation showed no significant difference in pelvic wall recurrence compared with PMB alone (p = 0·49).
Individually customised 2D PMBs with 3D image-based ICRT was safe and improved pelvic wall control in locally advanced cervix cancer. Dose-escalated combined boosts offered no significant benefit over standard boost doses.
Locally advanced cervix cancer is a major health problem in resource-limited areas of the world. Brachytherapy following pelvic chemoradiation is challenging, as large irregular clinical target volumes need adequate dose delivery while respecting limits of normal tissue tolerance. Achieving this is practically impossible using intracavitary brachytherapy alone. Consequently, combined intracavitary and interstitial brachytherapy provides higher chances of local control.
The advent of containerless processing techniques has opened the possibility of high quality measurements of equilibrium and metastable liquids. This review focuses on the structure and dynamics of metallic liquids at high temperature. A clear connection between structure, viscosity, and fragility has emerged from recent containerless experiments and molecular dynamics simulation studies. The temperature-dependent changes of liquid structures are smaller for the stronger liquids. The onset of cooperativity usually occurs above the liquidus temperature at a characteristic temperature TA, where the dynamics change from Arrhenius to non-Arrhenius behavior; this is accompanied by the onset of development of more spatially extended structural order in the liquids. Several metrics for fragility, consistent with the traditional fragility parameter, can be developed from the structural and dynamical properties at high temperature. It is becoming increasingly evident from theory and experiments that the fundamental properties that determine fragility are the repulsive part of the interatomic potential and the anharmonicity.
A comparative study of ferroelectric and non-ferroelectric-gated organic field-effect transistors (FETs) have been carried out by using a small molecule semiconductor 6,13 bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) to understand the fundamental aspects of carrier transport in FET architectures. Temperature-dependent current-voltage characteristics from non-ferroelectric dielectric-gated FETs show a clear activated transport, independent of the dielectric constant. While using the ferroelectric dielectric polymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE), where the dielectric constant may be tuned by changing the temperature, a negative temperature coefficient of the carrier mobility is observed beyond 200 K. The polarization fluctuation dominant transport inherent to a ferroelectric dielectric in conjunction with the discrete nature of traps in TIPS-pentacene results in an effective de-trapping of the shallow trap states into more mobile states.
To explore possible predictors of early vaginal stenosis among patients with locally advanced cervix cancer on pelvic chemoradiation.
Patients and methods
A total of 232 patients with locally advanced cervix cancer, who received pelvic radiotherapy at our institute from November 2011 to October 2013, were prospectively studied. Possible predictors chosen were age, tumour stage, initial vaginal involvement, concomitant chemotherapy and development of vaginitis of Radio Therapy Oncology Group grade 2 or more during radiotherapy. Multiple logistic regression was carried out to assess predictors and the relative risk of predictors was calculated.
Initial vaginal involvement and addition of concomitant chemotherapy are predictors of early vaginal stenosis in locally advanced cervix cancer patients on pelvic chemoradiation. Relative risk for early vaginal stenosis with vaginal involvement at presentation was 16·31, whereas that for concomitant chemotherapy was 9·95.
Among patients with locally advanced cervix cancer receiving pelvic chemoradiation, two factors, namely, initial vaginal involvement and concomitant chemotherapy are predictive of early vaginal stenosis. Patients with these factors should be assessed at regular intervals for early vaginal stenosis during pelvic chemoradiation to assess the optimal timing of intracavitary brachytherapy. This is particularly of importance in the absence of facilities for interstitial brachytherapy to ensure appropriate target coverage.
Interest in patterned polymer-based flexible nanodevices and sub-100 nm metal and transparent conducting nanostructured electrodes have led us to modify the traditional nanoimprint lithography technique to enable fabrication of an array of sub-100 nm diameter electrode structures. Transparent conducting electrodes (TCOs) are fabricated by coating one or multiple TCO layers of choice on top of a polymer nanostructured scaffold of appropriate dimension. By optimizing the thickness of each of these layers one may tune and optimize the trade-off between the conductivity and transparency of the sample. Incorporation of plasmonic materials such as Ag leads to interplay of localized and tunable surface plasmon resonances within the TCO structures. At plasmon resonance the reflection of the sample is minimized and absorption in the TCO structures dominates. Experimental and simulated reflection spectra of these structures are in good agreement, including the appearance of sharp spectral features that are absent in a simple planar analog. The simulated Brewster angle of the nanopillars decreases compared to the planar reference sample by up to 10-13 degrees depending on the height of the pillars and indicates a reduced effective refractive index. The depolarization factor obtained by ellipsometry is about 0.05, as anticipated for ellipsoidal pillars.
A versatile and powerful new lithographic fabrication method has been used to fabricate a number of nano-architectured ordered 2-D indium tin oxide (ITO) and silver (Ag) electrodes. By careful tuning of the dimensions of the nanofeatures in the electrodes, the surface area can be enhanced as desired, in-turn changing resistivity and free carrier concentrations accordingly. Absorption spectra of the samples show the existence of a new optical bandgap, in addition to the bulk bandgap, that is smaller. Nanostructured electrodes show enhanced transparency compared to their planar counterparts and demonstrate typical surface plasmon characteristics. The resonance frequency can be tuned as well by changing the dimensions of the nanofeatures in the electrodes.
Highly efficient Pt-TiO2 composite photoelectrodes were synthesized by combining two novel deposition methods: ACVD and a room temperature RF (radio frequency) magnetron sputtering method. A room temperature RF magnetron sputtering method allowed uniform deposition of Pt nanoparticles (NPs) onto the as-synthesized nanostructured columnar TiO2 films by ACVD. Pt NP sizes from 0.5 to 3 nm demonstrating a high particle density (>1012 cm−2) could be achieved by varying deposition time with constant pressure and power intensity. As-synthesized Pt-TiO2 films were used as photoanodes for water photolysis. Pt nanoparticles deposited onto the TiO2 film for 20s produced the highest photocurrent (7.92 mA/cm2 to 9.49 mA/cm2) and maximized the energy conversion efficiency (16.2 % to 21.2 %) under UV illumination. However, as the size of Pt particles increased, more trapping sites for photogenerated electron-hole pairs decreased photoreaction.
New information on the phase diagrams of Ti-Fe-Si-O and Ti-Zr-Ni alloys near the quasicrystal and rational approximant compositions is presented. α(TiFeSiO), the 1/1 rational approximant, is shown to form in a peritectic mode from the liquid, indicating the possibility to produce single-crystal samples. Very long duration annealing studies demonstrate unambiguously that the TiZrNi i-phase and 1/1 approximant form at low temperatures by a solid-state transformation; their phase fields do not extend to the liquidus temperatures. The first undercooling measurements of electrostatically-levitated droplets of the Ti-Zr-Ni alloys are presented. These nucleation studies provide new information on the structural relations between polytetrahedral phases and the undercooled liquid, and on the phase transformation processes. The reduced undercooling for the polytetrahedral phases in these alloys is less than for crystal phases of a similar composition, demonstrating a low interfacial energy between the polytetrahedral phase and the liquid.
Supercritical fluids (SF) have been used in a wide variety of applications:
in industrial processes, analytical, waste detoxification, etc. Recently,
its usefulness extends to the semiconductor industry. Researches have shown
that supercritical CO2 (SCCO2) can be used to remove
photoresists and significantly reduce the amount of waste from solvents in
comparison to conventional stripping techniques. SF will also find its
usefulness in cleaning high aspect ratio vias and deep trenches as
semiconductor features shrink to submicron levels. We will report here the
use of supercritical CO2 treatments in extraction of porogens
from a nanohybrid film fabricated via templated-porogen approach. Its use as
a medium to repair the damage in porous films from plasma ashing will also
be presented. The ability to tune the solvation and diffusion power of
SCCO2 and to swell the film matrix make it a good medium for
silylation to restore hydrophobicity and functionalize the film.
A vapor deposition technique has been used to prepare nano-size particles of Fe, Co and Ni using argon gas. The particles were passivated from further oxidation using a small volume of air. The range of particle size obtained in these systems was 47–200 Å. The saturation magnetization of Fe particles varied between 25–200 emu/g with the higher values corresponding to larger particles and the highest coercivity achieved at room temperature was 1050 Oe. In the case of Co and Ni, the magnetization varied in the range 35–100 emu/g and 14–45 emu/g, respectively. The highest room temperature coercivity was 1200 and 41 Oe for Co and Ni, respectively. A shell-type structure consisting of a metallic core surrounded by an oxide shell has been proposed for the particles.
The surface regions of α-alumina and hot pressed silicon nitride were modified by suitable alloying in order to improve their wear resistance. The surface modification in polycrystalline α-alumina was done by diffusing chromia into the surface region which resulted in the formation of a thin layer of A12O3 - Cr9O3 solid solution which has a lower thermal expansion coefficient than pure α-alumina. Also Cr2O3 has a larger lattice parameter than α-alumina thus during cooling the surface was put into compression. The surface region of hot pressed silicon nitride was modified by diffusing α-alumina into the surface which resulted in the formation of a thin sialon layer. A surface compressive stress was again introduced due to the lower thermal expansion coefficient and larger latticeparameter of sialon compared to silicon nitride.
Wear tests were conducted against 52100 steel under both lubricated and unlubricated sliding contact using a block on ring apparatus. The wear resistance of chromia surface alloyed α-alumina was improved considerably over unalloyed α-alumina under both lubricated and unlubricated conditions. The wear resistance of alumina surface alloyed silicon nitride was also improved over unalloyed silicon nitride under both lubricated and unlubricated conditions.
Different wear modes were identified by examining the worn surfaces under the scanning electron microscope.