1,074 research outputs found
Dosimetric impact of gastrointestinal air column in radiation treatment of pancreatic cancer
OBJECTIVE:
Dosimetric evaluation of air column in gastrointestinal (GI) structures in intensity modulated radiation therapy (IMRT) of pancreatic cancer.
METHODS:
Nine sequential patients were retrospectively chosen for dosimetric analysis of air column in the GI apparatus in pancreatic cancer using cone beam CT (CBCT). The four-dimensional CT (4DCT) was used for target and organs at risk (OARs) and non-coplanar IMRT was used for treatment. Once a week, these patients underwent CBCT for air filling, isocentre verification and dose calculations retrospectively.
RESULTS:
Abdominal air column variation was as great as ±80% between weekly CBCT and 4DCT. Even with such a large air column in the treatment path for pancreatic cancer, changes in anteroposterior dimension were minimal (2.8%). Using IMRT, variations in air column did not correlate dosimetrically with large changes in target volume. An average dosimetric deviation of mere -3.3% and a maximum of -5.5% was observed.
CONCLUSION:
CBCT revealed large air column in GI structures; however, its impact is minimal for target coverage. Because of the inherent advantage of segmentation in IMRT, where only a small fraction of a given beam passes through the air column, this technique might have an advantage over 3DCRT in treating upper GI malignancies where the daily air column can have significant impact. Advances in knowledge: Radiation treatment of pancreatic cancer has significant challenges due to positioning, imaging of soft tissues and variability of air column in bowels. The dosimetric impact of variable air column is retrospectively studied using CBCT. Even though, the volume of air column changes by ± 80%, its dosimetric impact in IMRT is minimum
Heterosis and Composition of Sweet Sorghum
Sweet sorghum (Sorghum bicolor) has potential as a bioenergy feedstock due to
its high yield potential and the production of simple sugars for fermentation. Sweet
sorghum cultivars are typically tall, high biomass types with juicy stalks and high sugar
concentration. These sorghums can be harvested, milled, and fermented to ethanol using
technology similar to that used to process sugarcane. Sweet sorghum has advantages in
that it can be planted by seed with traditional planters, is an annual plant that quickly
produces a crop and fits well in crop rotations, and it is a very water-use efficient crop.
Processing sweet sorghum is capital intensive, but it could fit into areas where sugarcane
is already produced. Sweet sorghum could be timed to harvest and supply the sugar mill
during the off season when sugarcane is not being processed, be fit into crop rotations, or
used in water limiting environments. In these ways, sweet sorghum could be used to
produce ethanol in the Southern U.S and other tropical and subtropical environments.
Traditionally, sweet sorghum has been grown as a pureline cultivar. However,
these cultivars produce low quantities of seed and are often too tall for efficient
mechanical harvest. Sweet sorghum hybrids that use grain-type seed parents with high sugar concentrations are one way to overcome limitation to seed supply and to capture
the benefits of heterosis.
There are four objectives of this research. First to evaluate the importance of
genotype, environment, and genotype-by-environment interaction effects on the sweet
sorghum yield and composition. The second objective is to determine the presence and
magnitude of heterosis effects for traits related to sugar production in sweet sorghum.
Next: to study the ability of sweet sorghum hybrids and cultivars to produce a ratoon
crop and determine the contribution of ratoon crops to total sugar yield. The final
objective is to evaluate variation in composition of sweet sorghum juice and biomass.
Sweet sorghum hybrids, grain-type sweet seed parents, and traditional cultivars
that served as male parents were evaluated in multi-environment trials in Weslaco,
College Station, and Halfway, Texas in 2007 and 2008. Both genotype and environment
influenced performance, but environment had a greater effect than genotype on the
composition of sweet sorghum juice and biomass yield. In comparing performance, elite
hybrids produced fresh biomass and sugar yields similar to the traditional cultivars while
overcoming the seed production limitations. High parent heterosis was expressed among
the experimental hybrids for biomass yield, sugar yield and sugar concentration.
Additional selection for combining ability would further enhance yields and heterosis in
the same hybrid. Little variation was observed among hybrids for juice and biomass
composition suggesting that breeding efforts should focus on yield before altering plant
composition
Characterizing Single Polymeric and Protein Nanoparticles with Surface Plasmon Resonance Imaging Measurements
Near-infrared surface plasmon resonance imaging (SPRI) microscopy is used to detect and characterize the adsorption of single polymeric and protein nanoparticles (PPNPs) onto chemically modified gold thin films in real time. The single-nanoparticle SPRI responses, Δ%R_(NP), from several hundred adsorbed nanoparticles are collected in a single SPRI adsorption measurement. Analysis of Δ%R_(NP) frequency distribution histograms is used to provide information on the size, material content, and interparticle interactions of the PPNPs. Examples include the measurement of log-normal Δ%R_(NP) distributions for mixtures of polystyrene nanoparticles, the quantitation of bioaffinity uptake into and aggregation of porous NIPAm-based (N-isopropylacrylamide) hydrogel nanoparticles specifically engineered to bind peptides and proteins, and the characterization of the negative single-nanoparticle SPRI response and log-normal Δ%R_(NP) distributions obtained for three different types of genetically encoded gas-filled protein nanostructures derived from bacteria
P9 - C.F.A.O : MISE AU POINT D’UN PROTOCOLE D’ÉVALUATION DES CONTRAINTES MÉCANIQUES POUR LES COIFFES PÉRIPHÉRIQUES « TOUT CÉRAMIQUE »
Effect of Elastic-Cord Towing on the Kinematics of the Acceleration Phase of Sprinting
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SLC19A1 transports immunoreactive cyclic dinucleotides.
The accumulation of DNA in the cytosol serves as a key immunostimulatory signal associated with infections, cancer and genomic damage1,2. Cytosolic DNA triggers immune responses by activating the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway3. The binding of DNA to cGAS activates its enzymatic activity, leading to the synthesis of a second messenger, cyclic guanosine monophosphate-adenosine monophosphate (2'3'-cGAMP)4-7. This cyclic dinucleotide (CDN) activates STING8, which in turn activates the transcription factors interferon regulatory factor 3 (IRF3) and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), promoting the transcription of genes encoding type I interferons and other cytokines and mediators that stimulate a broader immune response. Exogenous 2'3'-cGAMP produced by malignant cells9 and other CDNs, including those produced by bacteria10-12 and synthetic CDNs used in cancer immunotherapy13,14, must traverse the cell membrane to activate STING in target cells. How these charged CDNs pass through the lipid bilayer is unknown. Here we used a genome-wide CRISPR-interference screen to identify the reduced folate carrier SLC19A1, a folate-organic phosphate antiporter, as the major transporter of CDNs. Depleting SLC19A1 in human cells inhibits CDN uptake and functional responses, and overexpressing SLC19A1 increases both uptake and functional responses. In human cell lines and primary cells ex vivo, CDN uptake is inhibited by folates as well as two medications approved for treatment of inflammatory diseases, sulfasalazine and the antifolate methotrexate. The identification of SLC19A1 as the major transporter of CDNs into cells has implications for the immunotherapeutic treatment of cancer13, host responsiveness to CDN-producing pathogenic microorganisms11 and-potentially-for some inflammatory diseases
Access to print literacy for children and young people with visual impairment: findings from a review of literature
Roles of T follicular helper cells and T follicular regulatory cells in Autoantibody Production in IL-2-deficient mice
Autoantibodies can result from excessive T follicular helper (Tfh) cell activity, whereas T follicular regulatory (Tfr) cells negatively regulate autoantibody production. IL-2 knockout (KO) mice on the BALB/c background have elevated Tfh responses, produce autoantibodies, and develop lethal autoimmunity. We analyzed Tfh and Tfr cells in IL-2 KO mice on the C57BL/6 (B6) genetic background. In B6 IL-2 KO mice, the spontaneous formation of Tfh cells and germinal center B cells was greatly enhanced, along with production of anti-DNA autoantibodies. IL-2 has been reported to repress Tfr cell differentiation; however, Tfr cells were not increased over wild-type levels in the B6 IL-2 KO mice. To assess Tfh and Tfr cell regulation of autoantibody production in IL-2 KO mice, we generated IL-2 KO mice with a T cell-specific deletion of the master Tfh cell transcription factor Bcl6. In IL-2 KO Bcl6 conditional KO (2KO-Bcl6TC) mice, Tfh cells, Tfr cells, and germinal center B cells were ablated. In contrast to expectations, autoantibody IgG titers in 2KO-Bcl6TC mice were significantly elevated over autoantibody IgG titers in IL-2 KO mice. Specific deletion of Tfr cells with Foxp3-cre Bcl6-flox alleles in IL-2 KO mice led to early lethality, before high levels of autoantibodies could develop. We found IL-2+/+ Tfr cell-deficient mice produce significant levels of autoantibodies. Our overall findings provide evidence that Tfh cells are dispensable for high-level production of autoantibodies and also reveal a complex interplay between Tfh and Tfr cells in autoantibody production and autoimmune disease
A comparative evaluation of two roadside brake testing procedures+
A field survey was conducted to evaluate two procedures designed to measure the effectiveness of motor vehicle braking systems. Selected failure rates and agreement measures were computed using a recently developed unified approach to the analysis of multivariate categorical data. It was found that the procedures agree only weakly, and that the agreement varied with certain pass/fail criteria. On the basis of conditional arguments, a moving-stopping test was found to be more stringent than a wheel removal inspection.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22847/1/0000408.pd
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