두경부암의 양성자치료 : 현재의 임상 적용 및 발전 방향

오동렬(Dongryul Oh) 대한두경부종양학회 2021 대한두경부 종양학회지 Vol.37 No.1

Intensity-modulated radiation therapy (IMRT) using X-rays is a standard technique implemented for treating head and n eck cancer (HNC). Compared to 3D conformal RT, IMRT can significantly reduce the radiation dose to surrounding normal tissues by using a highly conformal dose to the tumor. Proton therapy is a type of RT that uses positively charged particles named protons. Proton therapy has a unique energy deposit (i.e., Bragg peak) and greater biological effectiveness than that of therapy using X-rays. These inherent properties of proton therapy make the technique advantageous for HNC treatment. Recently, advanced techniques such as intensity-modulated proton therapy have further decreased the dose to normal organs with a higher conformal dose to the tumor. The usage of proton therapy for HNC is becoming widespread as the number of operational proton therapy centers has increased worldwide. This paper aims to present the current clinical evidence of proton therapy utility to HNC clinicians through a literature review. It also discusses the challenges associated with proton therapy and prospective development of the technique.

Proton beam flux dependent work function of mono-layer MoS₂

Kwon, Sangwoo,Choi, Soo Ho,Kim, You Joong,Yoon, Im Taek,Yang, Woochul Elsevier 2018 THIN SOLID FILMS - Vol.660 No.-

<P><B>Abstract</B></P> <P>Monolayer (ML)-molybdenum disulfide (MoS<SUB>2</SUB>) with a direct band gap of ~1.8 eV exhibits considerable potential for advanced electronic and optical device applications. The surface electronic properties of ML-MoS<SUB>2</SUB> need to be controlled for developing novel MoS<SUB>2</SUB>-based devices. In this study, we investigated the work function variation of chemical vapor deposition-grown ML-MoS<SUB>2</SUB> that was controlled by proton irradiation. The crystallinity of the ML-MoS<SUB>2</SUB> was confirmed by micro-Raman and Photoluminescence measurements. The work functions of the ML-MoS<SUB>2</SUB> irradiated with varying proton beam flux were measured by Kelvin probe force microscopy. As the ML-MoS<SUB>2</SUB> were exposed to the proton beam flux ranging from 1 × 10<SUP>12</SUP> to 1 × 10<SUP>14</SUP> protons/cm<SUP>2</SUP> at the same beam energy of 10 MeV, the contact potential difference of the MoS<SUB>2</SUB> increased up to about 0.108 V with increased proton beam flux. Based on the referenced value of the Au work function (≈5.1 eV), the work functions of non-treated ML-MoS<SUB>2</SUB> and proton-irradiated ML-MoS<SUB>2</SUB> with a proton beam flux of 1 × 10<SUP>14</SUP> protons/cm<SUP>2</SUP> were determined to be 5.031 eV and 4.992 eV, respectively. The decrease of the work function of the MoS<SUB>2</SUB> with increased proton beam flux is due to the defect formation induced by proton irradiation. We suggest the possibility of engineering the surface potential and electronic properties of ML-MoS<SUB>2</SUB> through controlling proton irradiation conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The work function of monolayer MoS<SUB>2</SUB> decreased with increased proton flux irradiation. </LI> <LI> The proton irradiation on MoS<SUB>2</SUB> leads to generation of the S-vacancy defects in MoS<SUB>2</SUB>. </LI> <LI> Electronic properties of monolayer MoS<SUB>2</SUB> can be modified by proton beam irradiation. </LI> </UL> </P>

Effects on the Proton Conduction Limiting Barriers and Trajectories in BaZr_0.875Y_0.125O₃ Due to the Presence of Other Protons

Gomez, Maria A.,Fry, Dana L.,Sweet, Marie E. The Korean Ceramic Society 2016 한국세라믹학회지 Vol.53 No.5

Kinetic Monte Carlo (KMC) and graph searches show that proton conduction limiting barriers and trajectories in $BaZr_{0.875}Y_{0.125}O_3$ are affected by the presence of other protons. At 1000 K, KMC limiting conduction barriers increase from 0.39 eV to 0.45 eV as the proton number is increased. The proton-proton radial distribution begins to rise at $2{\AA}$ and peaks at $4{\AA}$, which is half the distance expected, based on the proton concentration. Density functional theory (DFT) calculations find proton/proton distances of 2.60 and $2.16{\AA}$ in the lowest energy two-proton configurations. A simple average of the limiting barriers for 7-10 step periodic long range paths found via graph theory at 1100 K shows an increase in activation barrier from 0.32 eV to 0.37 eV when a proton is added. Both KMC and graph theory show that protons can affect each other's pathways and raise the overall conduction barriers.

Proton Transfer Accounting for Anomalous Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pair of Cytosine and Guanine

Park, Jeong Ju,Lee, Choong Sik,Han, Sang Yun Springer US 2018 Journal of the American Society for Mass Spectrome Vol.29 No.12

<P>To understand the anomalous collision-induced dissociation (CID) behavior of the proton-bound Hoogsteen base pair of cytosine (C) and guanine (G), C:H<SUP>+</SUP>∙∙∙G, we investigated CID of a homologue series of proton-bound heterodimers of C, 1-methylcytosine, and 5-methylcytosine with G as a common base partner. The CID experiments were performed in an energy-resolved way (ER-CID) under both multiple and near-single collision conditions. The relative stabilities of the protonated complexes examined by ER-CID suggested that the proton-bound complexes produced by electrospray ionization in this study are proton-bound Hoogsteen base pairs. On the other hand, in contrast to the other base pairs, CID of C:H<SUP>+</SUP>∙∙∙G exhibited more abundant productions of C:H<SUP>+</SUP>, the fragment protonated on the moiety with a smaller proton affinity, than that of G:H<SUP>+</SUP>. This appeared to contradict general prediction based on the kinetic method. However, further theoretical exploration of potential energy surfaces found that there can be facile proton transfers in the proton-bound Hoogsteen base pairs during the CID process, which makes the process accessible to an additional product state of O-protonated C for C:H<SUP>+</SUP> fragments. The presence of an additional dissociation channel, which in other words corresponds to twofold degeneracy in the transition state leading to C:H<SUP>+</SUP> fragments, effectively doubles the apparent reaction rate for production of C:H<SUP>+</SUP>. In this way, the process gives rise to the anomaly, the observed pronounced formation of C:H<SUP>+</SUP> in the CID of the proton-bound Hoogsteen base pair, C:H<SUP>+</SUP>∙∙∙G.</P> [FIG OMISSION]</BR>

A sulfonated poly(arylene ether sulfone)/polyimide nanofiber composite proton exchange membrane for microbial electrolysis cell application under the coexistence of diverse competitive cations and protons

Park, Sung-Gwan,Chae, Kyu-Jung,Lee, Mooseok Elsevier 2017 Journal of membrane science Vol.540 No.-

<P><B>Abstract</B></P> <P>A sulfonated poly(arylene ether sulfone) (SPAES)/polyimide nanofiber (PIN) composite proton exchange membrane was developed for use in microbial electrolysis cells (MECs), where diverse cations that compete with proton coexist in high concentrations. It was fabricated by impregnating SPAES as a proton-conducting polymer into PIN as a supporter for mechanical reinforcement. The membrane showed excellent mechanical and dimensional stability (tensile strength > 40MPa) due to membrane reinforcement by nanofibers, despite having a high water uptake (35 ± 3%) and ion exchange capacity (2.3 ± 0.3meq/g). This novel membrane was highly selective for protons while excluding other competing cations; thus, it significantly mitigated the proton accumulation problem in the anode when applied to actual MECs. In addition to 1.5-fold greater proton transport, the SPAES/PIN membrane exhibited 3–10-fold less undesirable crossover of other cations depending on the species and 2–2.5-fold less gas permeability compared to Nafion-211 membrane. The application of this membrane improved hydrogen production efficiency of MEC by 32.4% compared to Nafion-211 and better hydrogen purity (90.3% for SPAES/PIN vs. 61.8% for Nafion-211). Therefore, this novel membrane has good potential for MEC applications, especially when protons and other competing cations are present together, due to its superior proton selectivity.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A hydrocarbon-based SPAES/PIN composite proton exchange membrane was developed. </LI> <LI> Sulfonated poly(arylene ether sulfone) (SPAES) was used as a proton conductor. </LI> <LI> The SPAES/PIN composite membrane showed excellent mechanical and dimensional stability. </LI> <LI> The novel membrane was highly selective for protons while excluding other competing cations. </LI> <LI> The membrane showed significant improvement over Nafion-211 for microbial electrolysis cell performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Post‐synthetic modifications in metal–organic frameworks for high proton conductivity

Sharma Amitosh,이성환,임재웅,나명수 대한화학회 2024 Bulletin of the Korean Chemical Society Vol.45 No.2

A myriad of metal ions and organic linkers can be used to produce metal–organic frameworks (MOFs) with varied functionalities, porosities, and dimensionalities. Such diversity has garnered significant research interest, particularly in leveraging MOFs as proton conductors for fuel cells. One effective approach involves introducing guest molecules into MOF pores. These molecules serve either as proton carriers or as proton‐conducting media through potential hydrogen bonding networks. This review offers an organized overview of key methodologies historically employed to achieve superprotonic conductivity in MOFs. The article systematically categorizes these tactics into three primary groups: guest molecule encapsulation, modulation at metal‐coordination sites, and ligand functionalization. We succinctly discuss the roles of proton carriers, conducting media, and the overall MOF framework, emphasizing the significance of each strategy's application. In conclusion, we provide insights into the future development of MOFs as proton conductors, rooted in the categorization and conceptual understanding of these strategies. A myriad of metal ions and organic linkers can be used to produce metal– organic frameworks (MOFs) with varied functionalities, porosities, and dimensionalities. Such diversity has garnered significant research interest, particularly in leveraging MOFs as proton conductors for fuel cells. One effective approach involves introducing guest molecules into MOF pores. These molecules serve either as proton carriers or as proton-conducting media through potential hydrogen bonding networks. This review offers an organized overview of key methodologies historically employed to achieve superprotonic conductivity in MOFs. The article systematically categorizes these tactics into three primary groups: guest molecule encapsulation, modulation at metal-coordination sites, and ligand functionalization. We succinctly discuss the roles of proton carriers, conducting media, and the overall MOF framework, emphasizing the significance of each strategy’s application. In conclusion, we provide insights into the future development of MOFs as proton conductors, rooted in the categorization and conceptual understanding of these strategies.

Protons are One of the Limiting Factors in Determining Sensitivity of Nano Surface-Assisted (+)-Mode LDI MS Analyses

Cho, Eunji,Ahn, Miri,Kim, Young Hwan,Kim, Jongwon,Kim, Sunghwan Springer US 2013 Journal of the American Society for Mass Spectrome Vol.24 No.10

<P>A proton source employing a nanostructured gold surface for use in (+)-mode laser desorption ionization mass spectrometry (LDI-MS) was evaluated. Analysis of perdeuterated polyaromatic hydrocarbon compound dissolved in regular toluene, perdeuterated toluene, and deuterated methanol all showed that protonated ions were generated irregardless of solvent system. Therefore, it was concluded that residual water on the surface of the LDI plate was the major source of protons. The fact that residual water remaining after vacuum drying was the source of protons suggests that protons may be the limiting reagent in the LDI process and that overall ionization efficiency can be improved by incorporating an additional proton source. When extra proton sources, such as thiolate compounds and/or citric acid, were added to a nanostructured gold surface, the protonated signal abundance increased. These data show that protons are one of the limiting components in (+)-mode LDI MS analyses employing nanostructured gold surfaces. Therefore, it has been suggested that additional efforts are required to identify compounds that can act as proton donors without generating peaks that interfere with mass spectral interpretation.</P> [FIG OMISSION]</BR>

Sulfonated poly(etheretherketone) based nanocomposite membranes containing POSS-SA for polymer electrolyte membrane fuel cells (PEMFC)

Kim, Sang-Woo,Choi, Seung-Young,Rhee, Hee-Woo Elsevier 2018 Journal of membrane science Vol.566 No.-

<P><B>Abstract</B></P> <P>Nanocomposite membranes were prepared using sulfonated polyhedral oligomeric silsesquioxane (POSS-SA) and incorporated into sulfonated polyetheretherketone (sPEEK) for their use in polymer electrolyte membrane fuel cells. The POSS-SA concentration was varied to investigate its effect on the nanostructure morphology, mechanical properties, proton conductivities, and cell performance of nanocomposite membranes. POSS-SA served as a plasticizer: The plasticizer effect of POSS-SA affected the formation of broadened proton-conducting nanochannels and enhanced the tensile strain of nanocomposite membranes. Tensile strain and yield modulus increased by 66.7% and 63.6%, respectively. Acidic POSS-SA served as a proton donor to sPEEK and increased the sPEEK nanochannel dimensions by 23%, leading to enhanced proton conductivities and cell performance. The highest proton conductivity and cell performance was achieved using 1.5 wt% of POSS-SA; these values decreased with > 1.5 wt% of POSS-SA, caused by the blocking of the nanochannels by POSS-SA aggregates. Compared with those observed for pristine sPEEK, the highest proton conductivity and maximum current density were 0.097 S/cm and 0.97 A/cm<SUP>2</SUP>, which were increased by 38.6% and 76.3%, respectively. Electrochemical impedance spectroscopy revealed that the superior cell performance with 1.5 wt% of POSS-SA is strongly related to the decreased interfacial resistance caused by expanded hydrophilic domains.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sulfonated POSS offered additional proton sources into nanochannels of sPEEK. </LI> <LI> 1.5 wt% was the optimum nanocomposite concentration which attain the highest conductivity and cell performance. </LI> <LI> Above 1.5 wt%, conductivity and cell performance was decreased due to blocking proton conduction by the aggregation of POSS-SA. </LI> <LI> POSS-SA reduced the interfacial resistance of MEA due to decreased T<SUB>g</SUB> and enhanced membrane flexibility. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Nanocomposite membranes were prepared using sulfonated polyhedral oligomeric silsesquioxane (POSS-SA) and incorporated into sulfonated polyetheretherketone (sPEEK) for their use in polymer electrolyte membrane fuel cells. The POSS-SA concentration was varied to investigate its effect on the nanostructure morphology, mechanical properties, proton conductivities, and cell performance of nanocomposite membranes. Acidic POSS-SA served as a proton donor to sPEEK and increased the sPEEK nanochannel dimensions by 23%, leading to enhanced proton conductivities and cell performance. The highest conductivity and current density at 0.6 V were 0.097 S/cm and 0.97 A/cm<SUP>2</SUP>, respectively, for 1.5 wt% of POSS-SA.</P> <P>[DISPLAY OMISSION]</P>

Comparison of Proton and Photon Beam Irradiation in Radiation-Induced Intestinal Injury Using a Mouse Model

Choi, Changhoon,Lee, Chansu,Shin, Sung-Won,Kim, Shin-Yeong,Hong, Sung Noh,Park, Hee Chul MDPI 2019 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.20 No.8

<P>When radiotherapy is applied to the abdomen or pelvis, normal tissue toxicity in the gastrointestinal (GI) tract is considered a major dose-limiting factor. Proton beam therapy has a specific advantage in terms of reduced doses to normal tissues. This study investigated the fundamental differences between proton- and X-ray-induced intestinal injuries in mouse models. C57BL/6J mice were irradiated with 6-MV X-rays or 230-MeV protons and were sacrificed after 84 h. The number of surviving crypts per circumference of the jejunum was identified using Hematoxylin and Eosin staining. Diverse intestinal stem cell (ISC) populations and apoptotic cells were analyzed using immunohistochemistry (IHC) and a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay, respectively. The crypt microcolony assay revealed a radiation-dose-dependent decrease in the number of regenerative crypts in the mouse jejunum; proton irradiation was more effective than X-ray irradiation with a relative biological effectiveness of 1.14. The jejunum is the most sensitive to radiations, followed by the ileum and the colon. Both types of radiation therapy decreased the number of radiosensitive, active cycling ISC populations. However, a higher number of radioresistant, reserve ISC populations and Paneth cells were eradicated by proton irradiation than X-ray irradiation, as shown in the IHC analyses. The TUNEL assay revealed that proton irradiation was more effective in enhancing apoptotic cell death than X-ray irradiation. This study conducted a detailed analysis on the effects of proton irradiation versus X-ray irradiation on intestinal crypt regeneration in mouse models. Our findings revealed that proton irradiation has a direct effect on ISC populations, which may result in an increase in the risk of GI toxicity during proton beam therapy.</P>

양성자 조사된 폴리아크릴로니트릴 필름의 광학적 특성

이화수,백가영,정진묵,황인태,정찬희,신준화,최재학 (사)한국방사선산업학회 2016 방사선산업학회지 Vol.10 No.1

Abstract - In this study, the effect of high-energy proton irradiation on the optical properties ofpolyacrylonitrile (PAN) films was investigated. PAN thin films spin-coated on a substrate wereirradiated 150 keV proton ions at various fluences. The changes in the chemical structure andoptical properties were investigated by FT-IR and UV-vis spectroscopy. The results of the FT-IRanalysis revealed that the cyclization reaction took place by proton irradiation and the degree ofcyclization increased with an increasing fluence. Based on the UV-vis analysis, the optical bandgap of PAN decreased from 2.84 to 2.52 eV with an increasing fluence due to the formation ofcarbon clusters by proton irradiation. In addition, the number of carbon atoms per carbon clusterand the number of carbon atoms per conjugation length were found to be increased with anincreasing fluence. In this study, the effect of high-energy proton irradiation on the optical properties ofpolyacrylonitrile (PAN) films was investigated. PAN thin films spin-coated on a substrate wereirradiated 150 keV proton ions at various fluences. The changes in the chemical structure andoptical properties were investigated by FT-IR and UV-vis spectroscopy. The results of the FT-IRanalysis revealed that the cyclization reaction took place by proton irradiation and the degree ofcyclization increased with an increasing fluence. Based on the UV-vis analysis, the optical bandgap of PAN decreased from 2.84 to 2.52 eV with an increasing fluence due to the formation ofcarbon clusters by proton irradiation. In addition, the number of carbon atoms per carbon clusterand the number of carbon atoms per conjugation length were found to be increased with anincreasing fluence.