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Search Results: 1 - 10 of 658 matches for " Proton "
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Preliminary Result of Hyperfractionated High-Dose Proton Beam Radiotherapy for Pediatric Skull Base Chordomas  [PDF]
Masashi Mizumoto, Hiroyoshi Akutsu, Tetsuya Yamamoto, Takashi Fukushima, Yoshiko Oshiro, Daichi Takizawa, Keiichi Tanaka, Masaaki Goto, Toshiyuki Okumura, Akira Matsumura, Koji Tsuboi, Hideyuki Sakurai
Journal of Cancer Therapy (JCT) , 2017, DOI: 10.4236/jct.2017.84028
Abstract: Objective: Proton beam therapy (PBT) may provide good local control for skull base chordoma and reduced toxicities, especially for pediatric patients. Methods: We evaluated the efficacy and safety of hyperfractionated high-dose PBT in6 pediatric patients with newly-diagnosed skull basechordoma who were treated with PBT at our institute from 2011 to 2015. The patients were 5 males and one female, and the median age was 9 years old (range: 5 - 13). All patients received surgery before PBT. The median period between surgery and PBT was 57 days (range: 34 - 129 days). The treatment dose was 78.4 GyE in 56 fractions (twice per day). Results: All patients received PBT without severe acute toxicity. The median follow-up period was 27 months (range: 21 - 71 months). At the last follow-up, all patients were alive and all tumors were well controlled. Acute and late toxicities were generally acceptable, with only grade 1 and 2 events. Late toxicities included growth hormone abnormality and cortical hormone abnormality. One patient needed growth hormone and cortical hormone replacement therapy. Conclusion: Although the number of pediatric patients was small, our overall findings in the 6 cases indicate that hyperfractionated high-dose PBT is safe and effective for pediatric patients with skull base chordoma.
An Interesting Mathematical Relation between the Proton Mass, the Proton Radius, the Fine Structure Constant, the Compton Wavelength and the Hagedorn Temperature  [PDF]
Espen Gaarder Haug
Journal of High Energy Physics, Gravitation and Cosmology (JHEPGC) , 2019, DOI: 10.4236/jhepgc.2019.52025
Abstract: In this short note we present a possible connection between the proton radius and the proton mass using the fine structure constant. The Hagedorn temperature is related to the energy levels assumed to be required to free the quarks from the proton, where hadronic matter is unstable. We also speculate that there could be a connection between the Hagedorn temperature and the Planck temperature through the fine structure constant. Regarding whether or not there is something to this (or if it is purely a coincidence), we will leave to others and future research to explore. However, we think these possible relationships are worth further investigation.
Characteristics of Filtered Neutron Beam Energy Spectra at Dalat Reactor  [PDF]
Tran Tuan Anh, Pham Ngoc Son, Vuong Huu Tan, Pham Dinh Khang, Phu Chi Hoa
World Journal of Nuclear Science and Technology (WJNST) , 2014, DOI: 10.4236/wjnst.2014.42015
Abstract:

Filtered neutron technique was applied for producing quasi-monoenergetic neutron beams of 24 keV, 54 keV, 133 keV and 148 keV at the horizontal neutron channel No. 4 of the Dalat Nuclear Research Reactor. The study on physical characteristics of these beam lines has been carried out for efficient applications in neutron capture experiments. The filtered neutron spectrum of each beam has been simulated by Monte-Carlo method and experimentally measured by a gas-filled protonrecoil spectrometer. The neutron fluxes of these filtered beams were measured by the activation technique with standard foils of 197Au, using a high efficient HPGe digital gamma-ray spectrometer.

Interaction between Warfarin and Proton Pump Inhibitors  [PDF]
Takeshi Shirayama, Hirokazu Shiraishi, Akira Kuroyanagi, Tetsuro Hamaoka, Mikimasa Imai, Akimitsu Kojima
International Journal of Clinical Medicine (IJCM) , 2014, DOI: 10.4236/ijcm.2014.514112
Abstract:

Background: Interaction between proton pump inhibitors (PPI) and warfarin is controversial. Previous clinical studies have only a short follow-up period. Methods and Results: All patients (n = 716) for whom warfarin was prescribed from November 1, 2010 to October 30, 2011 were extracted from electronic health records. In retrospective analysis for 1 year, PPI were prescribed to 404 patients. Among them, 108 patients were taking warfarin for more than 6 weeks before and after PPI. The profile of these patients was analyzed: 63 patients took lansoprazole; 15 patients took omeprazole; 30 patients took rabeprazole. No statistical difference was observed among 3 groups in age, body weight, concomitant use of other drugs, and comorbidity. Warfarin dose and INR did not change after PPI. Multivariate stepwise logistic regression analysis revealed that upper quartile of increment of INR was associated with the presence of atrial fibrillation (OR 3.77, 95% CI 1.16 - 12.27). The patients who had warfarin for shorter periods before PPI, or those who had PPI first (n = 141) had similar dose of warfarin and INR. In all patients analyzed (n = 404), including patients whose follow-up periods were shorter than 6 weeks (n = 155), a patient had cerebral bleeding, and 2 patients had cerebral infarction. Conclusions: Unfavorable interaction between warfarin and PPI was negligible in clinical use. Relatively higher INR was achieved after PPI in the presence of atrial fibrillation.

Electron—Proton Twins, Orderly Arranged in The Inside of Bioatoms  [PDF]
John C. Stavridis, George Baltatzis, Constantine N. Pattas
Open Journal of Physical Chemistry (OJPC) , 2012, DOI: 10.4236/ojpc.2012.24034
Abstract: In the present study the first 20 microatoms of the periodic table are named as bioatoms, since they are needed for biochemical functions and services to life itself. The rationale behind this project is the detailed analysis of the ionization energy of the electrons in the inside of the bioatoms and their orderly arrangement at specific positions. Such position of the electrons is harmonized with the succession of their energy values in their logarithmic curves. The compelling arrangement of each electron at a particular place would not be feasible in the absence of an energy offset, which is a proton. The latter would hold electrons on their proper position. These fundamental aspects of our project receive such strong support from the quantum theory, according to which it is the electromagnetic interaction between electrons and protons by the exchange of photons, which hold them together in the atoms. According to our proposed model, the protons of the aforementioned proton—electron twins, are distributed on distinct positions which are the junctions of a primary network, coupled with their electrons, in a secondary network. The geometry and distance of the protons, in the plexus, is constant and is calculated at 8, 42 ?. This was estimated by a mathematical analysis of the proposed model, as discussed further. Our study has shown that electrons in the specific positions are moving in a symmetrical oscillation in the length of a channel, in vacuum, under the Coulomb forces. Moreover, the chemical evidence suggests that electrons, in an atom, have their own separate orbit, and that these orbits are closely interrelated.
Variation of Total Ozone during 24 August 2005 Magnetic Storm: A Case Study  [PDF]
Gustavo A. Mansilla
Atmospheric and Climate Sciences (ACS) , 2013, DOI: 10.4236/acs.2013.34049
Abstract:

This paper presents the longitudinal distribution of total ozone along several latitudinal circles from both hemispheres during a strong geomagnetic storm that occurred on 24 August 2005 after a solar proton event (the maximum flux of protons with energy > 10 MeV was 1.70 × 107 protons cm-2.day-1.sr-1 on 23 August). For that, we use average daily values of total ozone observations (=column ozone amount) in Dobson units for the period 18-25 August 2005 (obtained from the Total Ozone Mapping Spectrometer, TOMS). The considered storm occurred after a relatively quiet geomagnetic period and it is not superposed by another perturbation, which permit us to identify clearly the effects of the geomagnetic storm on total ozone. The results show statistically significant decreases in ozone along the latitudinal circles 70°N and 70°S (summer and winter), no statistically significant effects at middle latitudes (40°S) and sparse statistically significant increases at low latitudes (20°S). The role of some mechanisms to explain the features observed is considered.

The Angular Momenta Dipole Moments and Gyromagnetic Ratios of the Electron and the Proton  [PDF]
A. Georgiou
Journal of Modern Physics (JMP) , 2014, DOI: 10.4236/jmp.2014.514125
Abstract:

We had previously obtained analytical formulae for the dipole moments and angular momenta of rotating spherical bodies. The resulting formulae were applied to the Sun, the star 78 Virginis and the Earth. The agreement of the theoretical formulae with the actual real situations is indeed remarkable. In this note we apply the same formulae to the electron and the proton, using the classical values of the radii, so no quantum mechanical treatment is considered.

Technological Progress in Radiation Therapy for Brain Tumors  [PDF]
Frederik Jozef Vernimmen, Kathy Rock
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.51005
Abstract:

To achieve a good therapeutic ratio the radiation dose to the tumor should be as high as possible with the lowest possible dose to the surrounding normal tissue. This is especially the case for brain tumors. Technological advancements in diagnostic imaging, dose calculations, and radiation delivery systems, combined with a better understanding of the pathophysiology of brain tumors have led to improvements in the therapeutic results. The widely used technology of delivering 3-D conformal therapy with photon beams (gamma rays) produced by Linear Accelerators has progressed into the use of Intensity modulated radiation therapy (IMRT). Particle beams have been used for several decades for radiotherapy because of their favorable depth dose characteristics. The introduction of clinically dedicated proton beam therapy facilities has improved the access for cancer patients to this treatment. Proton therapy is of particular interest for pediatric malignancies. These technical improvements are further enhanced by the evolution in tumor physiology imaging which allows for improved delineation of the tumor. This in turn opens the potential to adjust the radiation dose to maximize the radiobiological effects. The advances in both imaging and radiation therapy delivery will be discussed.

Proton Therapy Results in the Treatment of Hepatocellular Carcinoma According to the Barcelona-Clinic Liver Cancer (BCLC) Staging System  [PDF]
Francesco Dionisi, Maurizio Amichetti
International Journal of Medical Physics,Clinical Engineering and Radiation Oncology (IJMPCERO) , 2015, DOI: 10.4236/ijmpcero.2015.42013
Abstract:
Proton therapy represents the most advanced form of radiotherapy currently available. Hepato-cellular carcinoma (HCC) has been extensively treated with proton therapy since 1983 with en-couraging results in terms of effectiveness and safety, as reported in recent research articles, systematic reviews and meta-analyses. In this report, we summarized for the first time the results of proton therapy treatment for HCC according with respect to the Barcelona Clinic Liver Cancer Staging System, the most adopted classification system for HCC which provides information on both prognostic prediction and treatment allocation.
Predictive Factors of Surgery in Peptic Stenosis of the Bulb  [PDF]
Mohamed Ben Mabrouk, Aida Ben Slama Trabelsi, Mehdi Ksiaa, Waad Farhat, Ali Jmaa, Ali Ben Ali
Open Journal of Gastroenterology (OJGas) , 2015, DOI: 10.4236/ojgas.2015.59021
Abstract: The bulb ulcer stenosis, becoming exceptional in developed countries, remains frequent in our country despite the use of the antisecretory. The purpose of our study was to study epidemiological, diagnostic, and evolutionary complication particularities, and to find potential predictive factors of resistance of ulcer stenosis of the bulb to the pump inhibitors Proton through a recent series. This is a retrospective and descriptive study involving 105 patients, treated for ulcer stenosis of the bulb between January 2007 and December 2012. All our patients had received inhibitors of Proton pump, parenterally for 7 days. They were divided into 2 groups according to their response to treatment: the first group (G1) was sensitive and the second (G2) was resistant. All patients of the G2 were operated. We had compared the two groups. There was no statistically significant difference concerning age, sex, blood group and smoking between the two groups. In univariate study, the age of the epigastralgies was greater than or equal to 9 years; the clapotage fasting, dilation and gastric atony, objectified by the oesogastroduodenal transit were significantly associated with the failure of medical treatment. Only gastric atony and seniority of the disease over 9 years were independent risk factors of resistance to the Proton pump inhibitors in multivariate study.
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