479 research outputs found
Light-addressable liquid crystal polymer dispersed liquid crystal
Scattering-free liquid crystal polymer-dispersed liquid crystal polymer (LCPDLC)
films are fabricated by combining a room temperature polymerizable liquid crystal (LC)
monomer with a mesogenic photosensitive LC. The morphological and photosensitive
properties of the system are analysed with polarized optical microscopy and high resolution
scanning and transmission electron microscopy. A two-phase morphology comprised of
oriented fibril-like polymeric structures interwoven with nanoscale domains of phase
separated LC exists. The nanoscale of the structures enables an absence of scattering which
allows imaging through the LCPDLC sample without optical distortion. The use of a
mesogenic monomer enables much smaller phase separated domains as compared to nonmesogenic systems. All-optical experiments show that the transmitted intensity, measured
through parallel polarizers, can be modulated by the low power density radiation (31
mW/cm2) of a suitable wavelength (532 nm). The reversible and repeatable transmission
change is due to the photoinduced trans-cis photoisomerization process. The birefringence
variation (0.01) obtained by optically pumping the LCPDLC films allow their use as an alloptical phase modulato
Quantifying carrier recombination at grain boundaries in multicrystalline silicon wafers through photoluminescence imaging
We present a method based on steady state photoluminescence (PL) imaging and modelling of the PL intensity profile across a grain boundary (GB) using 2D finite element analysis, to quantify the recombination strength of a GB in terms of the effective surface recombination velocity (S e f f). This quantity is a more meaningful and absolute measure of the recombination activity of a GB compared to the commonly used signal contrast, which can strongly depend on other sample parameters, such as the intra-grain bulk lifetime. The method also allows the injection dependence of the S e f f of a given GB to be explicitly determined. The method is particularly useful for studying the responses of GBs to different cell processing steps, such as phosphorus gettering and hydrogenation. The method is demonstrated on double-side passivated multicrystalline wafers, both before and after gettering, and single-side passivated wafers with a strongly non-uniform carrier density profile depth-wise. Good agreement is found between the measured PL profile and the simulated PL profile for both cases. We demonstrate that single-side passivated wafers allow more recombination active grain boundaries to be analysed with less unwanted influence from nearby features. The sensitivity limits and other practical constraints of the method are also discussed
Radiobiological Evaluation of Intensity Modulated Radiation Therapy Treatments of Patients with Head and Neck Cancer: A Dual-Institutional Study
In clinical practice, evaluation of clinical efficacy of treatment planning stems from the radiation oncologist\u27s experience in accurately targeting tumors, while keeping minimal toxicity to various organs at risk (OAR) involved. A more objective, quantitative method may be raised by using radiobiological models. The purpose of this work is to evaluate the potential correlation of OAR-related toxicities to its radiobiologically estimated parameters in simultaneously integrated boost (SIB) intensity modulated radiation therapy (IMRT) plans of patients with head and neck tumors at two institutions. Lyman model for normal tissue complication probability (NTCP) and the Poisson model for tumor control probability (TCP) models were used in the Histogram Analysis in Radiation Therapy (HART) analysis. In this study, 33 patients with oropharyngeal primaries in the head and neck region were used to establish the correlation between NTCP values of (a) bilateral parotids with clinically observed rates of xerostomia, (b) esophagus with dysphagia, and (c) larynx with dysphagia. The results of the study indicated a strong correlation between the severity of xerostomia and dysphagia with Lyman NTCP of bilateral parotids and esophagus, respectively, but not with the larynx. In patients without complications, NTCP values of these organs were negligible. Using appropriate radiobiological models, the presence of a moderate to strong correlation between the severities of complications with NTCP of selected OARs suggested that the clinical outcome could be estimated prior to treatment
Defining the value framework for prostate brachytherapy using patient-centered outcome metrics and time-driven activity-based costing
Patient age is related to decision-making, treatment selection, and perceived quality of life in breast cancer survivors
BACKGROUND: Patients with breast cancer must choose among a variety of treatment options when first diagnosed. Patient age, independent of extent of disease, is also related to quality of life. This study examined the impact of patient age on treatment selected, factors influencing this selection, and perceived quality of life. METHODS: A 62-question survey evaluating breast cancer treatment and quality of life was mailed to breast cancer survivors. Responses were stratified by age (<50, 50-65, >65Â years) and extent of disease. RESULTS: Of the 1,131 surveys mailed, 402 were included for analysis. There were 104, 179, and 119 women aged <50, 50-65, and >65Â years, respectively. The median patient age was 58Â years, and the average interval from diagnosis to survey participation was 31.5Â months. CONCLUSIONS: Young women were more likely to have undergone aggressive therapies and had better physical functioning than old women. Old patients reported good quality of life and body image. Clinicians should consider patient age when discussing breast cancer treatment options
The Pervasive Crisis of Diminishing Radiation Therapy Access for Vulnerable Populations in the United States—Part 4: Appalachian Patients
Purpose: Compared with the rest of the United States, the population of Appalachia has lower education levels, higher rates of poverty, and limited access to health care. The presence of disparities in radiation therapy (RT) access for Appalachian patients with cancer has rarely been examined.
Methods and materials: The National Cancer Institute initiatives toward addressing disparities in treatment access for rural populations were examined. An extensive literature search was undertaken for studies investigating RT access disparities in Appalachian patients, beginning with the most common cancers in these patients (lung, colorectal, and cervical).
Results: Although the literature investigating RT access disparities in Appalachia is relatively sparse, studies examining lung, colorectal, cervical, prostate, head and neck, breast, and esophageal cancer, as well as lymphoma, indicate an unfortunate commonality in barriers to optimal RT access for Appalachian patients with cancer. These barriers are predominantly socioeconomic in nature (low income and lack of private insurance) but are exacerbated by paucities in both the number and quality of radiation centers that are accessible to this patient population.
Conclusions: Regardless of organ system, there are significant barriers for Appalachian patients with cancer to receive RT. Such diminished access is alarming and warrants resources devoted to addressing these disparities, which often go overlooked because of the assumption that the overall wealth of the United States is tangibly applicable to all of its citizens. Without intelligently targeted investments of time and finances in this arena, there is great risk of exacerbating rather than alleviating the already heavy burden facing Appalachian patients with cancer
Adaptation of the Stanford technique for treatment of bulky cutaneous T-cell lymphoma of the head
Non-alcoholic fatty liver disease: a multicentre clinical study BY the Italian Association for the Study of the Liver
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