237 research outputs found
A Model-Based Method for Assessment of Salivary Gland and Planning Target Volume Dosimetry in Volumetric-Modulated Arc Therapy Planning on Head-and-Neck Cancer.
This study examined the relationship of achievable mean dose and percent volumetric overlap of salivary gland with the planning target volume (PTV) in volumetric-modulated arc therapy (VMAT) plan in radiotherapy for a patient with head-and-neck cancer. The aim was to develop a model to predict the viability of planning objectives for both PTV coverage and organs-at-risk (OAR) sparing based on overlap volumes between PTVs and OARs, before the planning process. Forty patients with head-and-neck cancer were selected for this retrospective plan analysis. The patients were treated using 6 MV photons with 2-arc VMAT plan in prescriptions with simultaneous integrated boost in dose of 70 Gy, 63 Gy, and 58.1 Gy to primary tumor sites, high-risk nodal regions, and low-risk nodal regions, respectively, over 35 fractions. A VMAT plan was generated using Varian Eclipse (V13.6), in optimization with biological-based generalized equivalent uniform dose (gEUD) objective for OARs and targets. Target dose coverage
Crater formation by fast ions: comparison of experiment with Molecular Dynamics simulations
An incident fast ion in the electronic stopping regime produces a track of
excitations which can lead to particle ejection and cratering. Molecular
Dynamics simulations of the evolution of the deposited energy were used to
study the resulting crater morphology as a function of the excitation density
in a cylindrical track for large angle of incidence with respect to the surface
normal. Surprisingly, the overall behavior is shown to be similar to that seen
in the experimental data for crater formation in polymers. However, the
simulations give greater insight into the cratering process. The threshold for
crater formation occurs when the excitation density approaches the cohesive
energy density, and a crater rim is formed at about six times that energy
density. The crater length scales roughly as the square root of the electronic
stopping power, and the crater width and depth seem to saturate for the largest
energy densities considered here. The number of ejected particles, the
sputtering yield, is shown to be much smaller than simple estimates based on
crater size unless the full crater morphology is considered. Therefore, crater
size can not easily be used to estimate the sputtering yield.Comment: LaTeX, 7 pages, 5 EPS figures. For related figures/movies, see:
http://dirac.ms.virginia.edu/~emb3t/craters/craters.html New version uploaded
5/16/01, with minor text changes + new figure
Evaluating of HPV-DNA ISH as an adjunct to p16 testing in oropharyngeal cancer
© 2020 Jeffrey Chi. Aim: Current guidelines recommend p16 immunohistochemistry (IHC) for testing human papillomavirus (HPV) in oropharyngeal carcinoma (OPSCC). We evaluated the value of adding DNA in situ hybridization (ISH) to p16 IHC. Methods: Fifty patients with OPSCC were analyzed. Concordance between HPV-DNA ISH and p16 IHC was measured by Gwet\u27s agreement coefficient. Results: p16 IHC was positive in 35/48 (72.9%), negative in 8/48 (16.7%) patients. Wide spectrum DNA-ISH was positive in 9/23 (39%) and negative in 14/23 (60.9%) patients. High-risk 16/18 (HR) HPV DNA-ISH was positive in 11/23 (47.8%) and negative in 12 (52.2%) patients. The agreement between HPV DNA-ISH and p16 IHC is fair (Gwet\u27s AC1 = 0.318). Conclusion: The agreement between p16 IHC and HPV-DNA ISH was fair. However, ISH sensitivity was low. Our findings add to the current data that p16 IHC testing is reliable and may be enough as a stand-alone test for HPV detection in OPSCC. Current testing guidelines recommend p16 immunochemistry (IHC) for detecting human papillomavirus (HPV) in oropharyngeal cancer (OPSCC). We evaluated the value of adding HPV DNA in situ hybridization (ISH) to p16 IHC. Fifty patients with OPSCC were analyzed. p16 IHC was positive in 72.9% of patients and DNA-ISH was positive in 39% of patients when wide spectrum probe was used and positive in 47.8% of patients when high-risk probe was used. The agreement between the two tests was fair. However, DNA-ISH sensitivity was low. p16 IHC may be enough as a stand-alone test for detection of HPV in OPSCC
Modern cities modelled as “super-cells” rather than multicellular organisms: Implications for industry, goods and services
The structure and “metabolism” (movement and conversion of goods and energy) of urban areas has caused cities to be identified as “super-organisms”, placed between ecosystems and the biosphere, in the hierarchy of living systems. Yet most such analogies are weak, and render the super-organism model ineffective for sustainable development of cities. Via a cluster analysis of 15 shared traits of the hierarchical living system, we found that industrialized cities are more similar to eukaryotic cells than to multicellular organisms; enclosed systems, such as factories and greenhouses, paralleling organelles in eukaryotic cells. We further developed a “super-cell” industrialized city model: a “eukarcity” with citynucleus (urban area) as a regulating centre, and organaras (enclosed systems, which provide the majority of goods and services) as the functional components, and cityplasm (natural ecosystems and farmlands) as the matrix. This model may improve the vitality and sustainability of cities through planning and management
Fermentation of deproteinized cheese whey powder solutions to ethanol by engineered Saccharomyces cerevisiae : effect of supplementation with corn steep liquor and repeated-batch operation with biomass recycling by flocculation
The lactose in cheese whey is an interesting
substrate for the production of bulk commodities such as
bio-ethanol, due to the large amounts of whey surplus
generated globally. In this work, we studied the performance
of a recombinant Saccharomyces cerevisiae strain
expressing the lactose permease and intracellular ß-galactosidase
from Kluyveromyces lactis in fermentations of
deproteinized concentrated cheese whey powder solutions.
Supplementation with 10 g/l of corn steep liquor significantly
enhanced whey fermentation, resulting in the production
of 7.4% (v/v) ethanol from 150 g/l initial lactose in
shake-flask fermentations, with a corresponding productivity
of 1.2 g/l/h. The flocculation capacity of the yeast
strain enabled stable operation of a repeated-batch process
in a 5.5-l air-lift bioreactor, with simple biomass recycling
by sedimentation of the yeast flocs. During five consecutive
batches, the average ethanol productivity was 0.65 g/l/h
and ethanol accumulated up to 8% (v/v) with lactose-toethanol
conversion yields over 80% of theoretical. Yeast
viability (>97%) and plasmid retention (>84%) remained
high throughout the operation, demonstrating the stability
and robustness of the strain. In addition, the easy and
inexpensive recycle of the yeast biomass for repeated utilization
makes this process economically attractive for
industrial implementation.Fundação para a Ciência e a Tecnologia (FCT)LACTOGAL-Produtos Alimentares S.A.Companhia Portuguesa de Amidos, S.A
Treatment of synthetic textile wastewater containing dye mixtures with microcosms
The aim was to assess the ability of microcosms (laboratory-scale shallow ponds) as a post polishing stage for the remediation of artificial textile wastewater comprising two commercial dyes (basic red 46 (BR46) and reactive blue 198 (RB198)) as a mixture. The objectives were to evaluate the impact of Lemna minor L. (common duckweed) on the water quality outflows; the elimination of dye mixtures, organic matter, and nutrients; and the impact of synthetic textile wastewater comprising dye mixtures on the L. minor plant growth. Three mixtures were prepared providing a total dye concentration of 10 mg/l. Findings showed that the planted simulated ponds possess a significant (p < 0.05) potential for improving the outflow characteristics and eliminate dyes, ammonium-nitrogen (NH4-N), and nitrate-nitrogen (NO3-N) in all mixtures compared with the corresponding unplanted ponds. The removal of mixed dyes in planted ponds was mainly due to phyto-transformation and adsorption of BR46 with complete aromatic amine mineralisation. For ponds containing 2 mg/l of RB198 and 8 mg/l of BR46, removals were around 53%, which was significantly higher than those for other mixtures: 5 mg/l of RB198 and 5 mg/l of BR46 and 8 mg/l of RB198 and 2 mg/l of BR46 achieved only 41 and 26% removals, respectively. Dye mixtures stopped the growth of L. minor, and the presence of artificial wastewater reduced their development
Frontal Non-Invasive Neurostimulation Modulates Antisaccade Preparation in Non-Human Primates
A combination of oculometric measurements, invasive electrophysiological recordings and microstimulation have proven instrumental to study the role of the Frontal Eye Field (FEF) in saccadic activity. We hereby gauged the ability of a non-invasive neurostimulation technology, Transcranial Magnetic Stimulation (TMS), to causally interfere with frontal activity in two macaque rhesus monkeys trained to perform a saccadic antisaccade task. We show that online single pulse TMS significantly modulated antisaccade latencies. Such effects proved dependent on TMS site (effects on FEF but not on an actively stimulated control site), TMS modality (present under active but not sham TMS on the FEF area), TMS intensity (intensities of at least 40% of the TMS machine maximal output required), TMS timing (more robust for pulses delivered at 150 ms than at 100 post target onset) and visual hemifield (relative latency decreases mainly for ipsilateral AS). Our results demonstrate the feasibility of using TMS to causally modulate antisaccade-associated computations in the non-human primate brain and support the use of this approach in monkeys to study brain function and its non-invasive neuromodulation for exploratory and therapeutic purposes
Lack of utility of risk score and gynecological examination for screening for sexually transmitted infections in sexually active adolescents
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