1,294 research outputs found
The efficacy of occlusal splints in the treatment of bruxism : A systematic review
Funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.Peer reviewedPostprin
Diffusion MR Characteristics Following Concurrent Radiochemotherapy Predicts Progression-Free and Overall Survival in Newly Diagnosed Glioblastoma.
The standard of care for newly diagnosed glioblastoma (GBM) is surgery, then radiotherapy (RT) with concurrent temozolomide (TMZ), followed by adjuvant TMZ. We hypothesized patients with low diffusivity measured using apparent diffusion coefficient (ADC) histogram analysis evaluated after RT+TMZ, prior to adjuvant TMZ, would have a significantly shorter progression-free (PFS) and overall survival (OS). To test this hypothesis we evaluated 120 patients with newly diagnosed GBM receiving RT+TMZ followed by adjuvant TMZ. MRI was performed after completion of RT+TMZ, prior to initiation of adjuvant TMZ. A double Gaussian mixed model was used to describe the ADC histograms within the enhancing tumor, where ADCL and ADCH were defined as the mean ADC value of the lower and higher Gaussian distribution, respectively. An ADCL value of 1.0 um2/ms and ADCH value of 1.6 um2/ms were used to stratify patients into high and low risk categories. Results suggest patients with low ADCL had significantly shorter PFS (Cox Hazard Ratio = 0.12, P = 0.0006). OS was significantly shorter with low ADCL tumors, showing a median OS of 407 vs. 644 days (Cox Hazard Ratio = 0.31, P = 0.047). ADCH was not predictive of PFS or OS when accounting for age and ADCL. In summary, newly diagnosed glioblastoma patients with low ADCL after completion of RT+TMZ are likely to progress and die earlier than patients with higher ADCL. Results suggest ADC histogram analysis may be useful for patient risk stratification following completion of RT+TMZ
Block Copolymer Cross-Linked Nanoassemblies Improve Particle Stability and Biocompatibility of Superparamagnetic Iron Oxide Nanoparticles
PURPOSE: To develop cross-linked nanoassemblies (CNAs) as carriers for superparamagnetic iron oxide nanoparticles (IONPs).
METHODS: Ferric and ferrous ions were co-precipitated inside core-shell type nanoparticles prepared by cross-linking poly(ethylene glycol)-poly(aspartate) block copolymers to prepare CNAs entrapping Fe(3)O(4) IONPs (CNA-IONPs). Particle stability and biocompatibility of CNA-IONPs were characterized in comparison to citrate-coated Fe(3)O(4) IONPs (Citrate-IONPs).
RESULTS: CNA-IONPs, approximately 30 nm in diameter, showed no precipitation in water, PBS, or a cell culture medium after 3 or 30 h, at 22, 37, and 43°C, and 1, 2.5, and 5 mg/mL, whereas Citrate-IONPs agglomerated rapidly (\u3e 400 nm) in all aqueous media tested. No cytotoxicity was observed in a mouse brain endothelial-derived cell line (bEnd.3) exposed to CNA-IONPs up to 10 mg/mL for 30 h. Citrate-IONPs (\u3e 0.05 mg/mL) reduced cell viability after 3 h. CNA-IONPs retained the superparamagnetic properties of entrapped IONPs, enhancing T2-weighted magnetic resonance images (MRI) at 0.02 mg/mL, and generating heat at a mild hyperthermic level (40 ~ 42°C) with an alternating magnetic field (AMF).
CONCLUSION: Compared to citric acid coating, CNAs with a cross-linked anionic core improved particle stability and biocompatibility of IONPs, which would be beneficial for future MRI and AMF-induced remote hyperthermia applications
Phytochemical Assays of Commercial Botanical Dietary Supplements
The growing popularity of botanical dietary supplements (BDS) has been accompanied by concerns regarding the quality of commercial products. Health care providers, in particular, have an interest in knowing about product quality, in view of the issues related to herb-drug interactions and potential side effects. This study assessed whether commercial formulations of saw palmetto, kava kava, echinacea, ginseng and St. John's wort had consistent labeling and whether quantities of marker compounds agreed with the amounts stated on the label. We purchased six bottles each of two lots of supplements from nine manufacturers and analyzed the contents using established commercial methodologies at an independent laboratory. Product labels were found to vary in the information provided, such as serving recommendations and information about the herb itself (species, part of the plant, marker compound, etc.) With regard to marker compound content, little variability was observed between different lots of the same brand, while the content did vary widely between brands (e.g. total phenolic compounds in Echinacea ranged from 3.9–15.3 mg per serving; total ginsenosides in ginseng ranged from 5.3–18.2 mg per serving). Further, the amounts recommended for daily use also differed between brands, increasing the potential range of a consumer's daily dose. Echinacea and ginseng were the most variable, while St. John's wort and saw palmetto were the least variable. This study highlights some of the key issues in the botanical supplement market, including the importance of standardized manufacturing practices and reliable labeling information. In addition, health care providers should keep themselves informed regarding product quality in order to be able to appropriately advise patients utilizing both conventional and herbal medicines
Molecular Dynamics Simulations of Phase Transition in AgNO3
Structural phase transition in AgNO3 at high temperature is simulated by molecular dynamics. The simulations are based on the potentials calculated from the Gordon–Kim modified electron-gas formalism extended to molecular ionic crystals. AgNO3 transforms into rhombohedral structure at high temperature and the phase transition is associated with the rotations of the NO3 ions and displacements of the NO3 and Ag ions
Nuclear safety policy working group recommendations on nuclear propulsion safety for the space exploration initiative
An interagency Nuclear Safety Working Group (NSPWG) was chartered to recommend nuclear safety policy, requirements, and guidelines for the Space Exploration Initiative (SEI) nuclear propulsion program. These recommendations, which are contained in this report, should facilitate the implementation of mission planning and conceptual design studies. The NSPWG has recommended a top-level policy to provide the guiding principles for the development and implementation of the SEI nuclear propulsion safety program. In addition, the NSPWG has reviewed safety issues for nuclear propulsion and recommended top-level safety requirements and guidelines to address these issues. These recommendations should be useful for the development of the program's top-level requirements for safety functions (referred to as Safety Functional Requirements). The safety requirements and guidelines address the following topics: reactor start-up, inadvertent criticality, radiological release and exposure, disposal, entry, safeguards, risk/reliability, operational safety, ground testing, and other considerations
Laser Guide Stars for Extremely Large Telescopes: Efficient Shack-Hartmann Wavefront Sensor Design using Weighted center-of-gravity algorithm
Over the last few years increasing consideration has been given to the study
of Laser Guide Stars (LGS) for the measurement of the disturbance introduced by
the atmosphere in optical and near-infrared astronomical observations from the
ground. A possible method for the generation of a LGS is the excitation of the
Sodium layer in the upper atmosphere at approximately 90 km of altitude. Since
the Sodium layer is approximately 10 km thick, the artificial reference source
looks elongated, especially when observed from the edge of a large aperture.
The spot elongation strongly limits the performance of the most common
wavefront sensors. The centroiding accuracy in a Shack-Hartmann wavefront
sensor, for instance, decreases proportionally to the elongation (in a photon
noise dominated regime). To compensate for this effect a straightforward
solution is to increase the laser power, i.e. to increase the number of
detected photons per subaperture. The scope of the work presented in this paper
is twofold: an analysis of the performance of the Weighted Center of Gravity
algorithm for centroiding with elongated spots and the determination of the
required number of photons to achieve a certain average wavefront error over
the telescope aperture.Comment: 10 pages, 14 figure
- …