Radiation resistance

The safety of irradiated pork packed in 25% CO2:75% N2 and stored at abuse temperature (10 or 15°C) was assessed by inoculation studies involving Salmonella typhimurium, Listeria monocytogenes, Escherichia coli, Yersinia enterocolitica and Clostridium perfringens. Irradiation to a dose of 1.75 kGy reduced pathogen numbers to below the detection limit of 102 cells g-1. When higher inoculum levels were used (106 cells g-1) irradiation at 1.75 kGy reduced pathogen numbers by 1 –>5 log10 cycles depending on strain. Clostridium perfringens was the most resistant, and Y. enterocolitica the most sensitive of the pathogens studied.In all cases when high numbers (106 to 107g-1) of spoilage and/or pathogenic bacteria were present initially on the pork the meat appeared spoiled, and although irradiation reduced the number of microorganisms, the meat was still unacceptable from a sensory viewpoint after treatment.It was concluded that the microbiological safety of irradiated, modified atmosp...

In this work, several "anti-rads" (highly conjugated aromatic compounds) were added to a commercial silicone sealant films as external radiation protective agents. This work introduces the use of protective agents against gamma radiation effects in silicone sealants. The "anti-rad" materials inhibit crosslinking that results upon exposure to gamma radiation.

Strain engineering based on either a global approach using high-mobility substrates or the implementation of so-called processing-induced stressors has become common practice for 90 nm and below CMOS technologies. Although the main goal is to improve the performance by increasing the drive current, other electrical parameters such as the threshold voltage, the multiplication current, the low frequency noise and the gate oxide quality in general may be influenced. This paper reviews the impact of different global and local strain engineering techniques on the gate stack quality and its reliability, including hot carrier performance, negative bias temperature instabilities, time dependent dielectric breakdown and radiation hardness. Recent insights will be discussed and the influence of different strain engineering approaches illustrated.

Cancer stem cells (CSCs) refer to a subset of tumor cells with the potential to self-renew and differentiate into different cancer subtypes, including leukemias and solid tumors. Dysregulated gene expression and alteration of critical signaling pathways have been observed in CSCs, compared to low-tumorigenic bulk tumor cells. CSCs are thought to be responsible for tumor onset, self-renewal/maintenance, recurrence, distant metastasis, angiogenesis, and drug/radiation resistance. In recent years, CSCs have attracted a great deal of attention due to the remarkable potential for the development of specific therapies targeting CSCs and the identification of key molecules that play a critical role in controlling the unique features of CSC-enriched populations. During the last several years, a tremendous amount of work has been done on developing new drugs and therapeutic products, such as small molecule inhibitors, antibodies, and
small interfering RNAs (siRNAs). These CSC-targeting agents selectively inhibit key components of various intrinsic signaling
pathways or specific cell surface markers of CSCs. Many novel therapeutic agents and new molecular targeting compounds have been tested, some of which are currently under investigation in preclinical and clinical trials. In this review
article, we provide an overview of the current status of the CSC hypothesis and discuss the various critical signaling pathways and specific cell surface markers involved in the development and maintenance of CSC populations. In addition, we also review various patents and CSC-targeting therapeutic strategies that may eventually lead to eradication of both bulk tumor cells and CSCs.

The conversion efficiency of InGaP/(In)GaAs/Ge -based multijunction solar cells has been improved up to 29-30% (AM0) and 31-32% (AM1Á5G) by technologies, such as double-hetero wide band-gap tunnel junctions, combination with Ge bottom cell with the InGaP first hetero-growth layer, and precise lattice-matching to Ge substrate by adding 1% indium to the conventional GaAs lattice-match structure. Employing a 1Á95 eV AlInGaP top cell should improve efficiency further. For space use, radiation resistance has been improved by technologies such as introducing of an electric field in the base layer of the lowest-resistance middle cell, and EOL current matching of sub-cells to the highest-resistance top cell. A grid structure and cell size have been designed for concentrator applications in order to reduce the energy loss due to series resistance, and 38% (AM1Á5G, 100-500 suns) efficiency has been demonstrated. Furthermore, thin-film structure which is InGaP/GaAs dual junction cell on metal film has been newly developed. The thin-film cell demonstrated high flexibility, lightweight, high efficiency of over 25% (AM0) and high radiation resistance.

Low tissue oxygen concentration has been shown to be important in the response of human tumors to radiation therapy, chemotherapy and other treatment modalities. Hypoxia is also known to be a prognostic indicator, as hypoxic human tumors are more biologically aggressive and are more likely to recur locally and metastasize. Herein, we discuss and summarize the various methods under investigation to directly or indirectly measure tissue oxygen in vivo. Secondly, we consider the advantages and disadvantages of each of these techniques. These considerations are made in light of our specific hypotheses that hypoxia should be measured as a continuum, not a binary measurement and that moderate, not severe hypoxia is of great biological consequence. q

We live in a world full of external factors that can harm our cellular DNA, causing mutations that disturb and disrupt the cellular lifecycle (Gelbart et al, 2000). Radiation, either x-ray or ultraviolet , is one of the most common mutagens we encounter daily. For example, we are exposed daily to UV radiation from the sun. Defence systems against radiation damage are a necessity for all living cells, in order to minimise the harmful effects of UV radiation. Living cells are indeed equipped with various ways to minimise damage by the activation of a vast array of DNA damage-repair systems, which have been thoroughly studied (Gelbart et al, 2000). The generation of mutations by radiation and their correction by DNA repair systems have been recognised as important subjects in high school biology curricula (American Association for the Advancement of Science [AAAS], 1994; Barker, 1983; Lock, 1997). Unfortunately, in spite of the prevalence of UV radiation in our lives, most students have minimal awareness of it and the effects on living organisms (Morimoto,2002). UV radiation and its effect on DNA were found to be particularly difficult subjects to learn, and students found this material too abstract (Johnstone and Mahmoud, 1980; Hallden, 1988; Pashley, 1994; Bahar et al, 1999). Furthermore, research has shown that students find the micro level (cellular and molecular) difficult to understand (Marbach-Ad and Stavy, 2000). One reason for the difficulties students encounter is the fact that the micro levels are generally taught in a theoretical manner, while the processes and components at these levels cannot be touched or directly observed (Marbach-Ad and Stavy, 2000). Marbach-Ad and Stavy (2000) suggested that UV radiation damage and bacterial DNA repair systems This paper reports on a simple hands-on laboratory procedure for high school students in studying both radiation damage and DNA repair systems in bacteria. The sensitivity to ultraviolet (UV) radiation of both Escherichia coli and Serratia marcescens is tested by radiating them for varying time periods. Two growth temperatures are used in order to induce the production of the melanin-like pigment prodigiosin in Serratia marcescens. Several explanations are then suggested for the differences observed, including cellular DNA repair systems and the presence of the intracellular pigment prodigiosin. The experiment's results prove that the different sensitivities to radiation of both bacterial strains are caused by cellular DNA repair systems, and not by other cellular molecules, such as the pigment prodigiosin. The paper also suggests further laboratory investigations designed to enhance high school students' understanding of bacterial DNA repair systems.

An accurate radiation degradation model, based on measured radiation damages to devices and physical principles on radiation-induced defects in Si, has been established to improve the radiation-resistance of the Czochralski (CZ)grown and floating-zone (FZ)-grown single-crystal Si space solar cells. We have successfully carried out the optimization of radiation-resistant Si space solar cells by taking into account the effective base carrier concentration dependence of the most important analytical parameters, damage coefficient KL KL KL for the minority-carrier diffusion length and carrier removal rate RC RC RC for majority-carrier. The model can be used to adequately predict the radiation degradation of the Si solar cells irradiated with a complete spectrum of electrons fluence. It has been established that the radiation-resistance of the silicon solar cell is very dependent on effective carrier concentration under high fluence range and irradiation tolerance can be improved further by varying the base carrier concentration upon irradiation.

The goal of this study was to develop an assay that makes possible the assessment of the glioma cell response to single-fraction high-dose Gamma Knife surgery. In this assay, the isolation of radioresistant cell subpopulations facilitates mechanistic studies of radioresistance. Methods. A tissue-equivalent paraffin phantom with an aperture capable of holding an Opticell cell culture cassette was developed for treatment with the Leksell Gamma Knife model C. A second apparatus, which the authors also created, uses the manufacturer-supplied polystyrene phantom, thereby allowing this assay to be performed in the Leksell Gamma Knife Perfexion. After treatment, the cells were morphologically assessed to determine their response to radiation treatment. Two specific parameters were used to determine radiosensitivity: 1) the diameter of the clearing zone, defined as the central region of cell death; and 2) the number of surviving colonies within this central high-dose clearing zone. Results. Radioresistance was compared in 2 different cell lines from glioblastomas. The first cell line, ME, was established from a primary tumor before its treatment, and the second cell line, DIV, was established from a tumor that recurred after treatment with chemotherapy and fractionated radiotherapy. The ME cell line had the most robust response to radiosurgery, as characterized by a consistently larger clearing zone (28.33 ± 1.1 mm). In contrast, the clearing zone produced when the DIV cell line was used was 24.0 ± 1 mm, indicating an approximate response difference of 5 Gy. The mean number of surviving colonies within the clearing zone for the ME cell line was 1.33 ± 1 compared with that for the DIV cell line, which was 66.67 ± 2. Conclusions. The authors developed a biological dosimeter to model the response of cells from glioblastomas to single-fraction high-dose radiation. This system also allows the identification and isolation of radioresistant cells.

The radiation impedance of a capacitive micromachined ultrasonic transducer (cMUT) with a circular membrane is calculated analytically using its velocity profile for the frequencies up to its parallel resonance frequency for both the immersion and the airborne applications. The results are verified by finite element simulations. The work is extended to calculate the radiation impedance of an array of cMUT cells positioned in a hexagonal pattern. A higher radiation resistance improves the bandwidth as well as the efficiency of the cMUT. The radiation resistance is determined to be a strong function of the cell spacing. It is shown that a center-to-center cell spacing of 1.25 wavelengths maximizes the radiation resistance, if the membranes are not too thin. It is also found that excitation of nonsymmetric modes may reduce the radiation resistance in immersion applications.

We live in a world full of external factors that can harm our cellular DNA, causing mutations that disturb and disrupt the cellular lifecycle (Gelbart et al, 2000). Radiation, either x-ray or ultraviolet , is one of the most common mutagens we encounter daily. For example, we are exposed daily to UV radiation from the sun. Defence systems against radiation damage are a necessity for all living cells, in order to minimise the harmful effects of UV radiation. Living cells are indeed equipped with various ways to minimise damage by the activation of a vast array of DNA damage-repair systems, which have been thoroughly studied (Gelbart et al, 2000). The generation of mutations by radiation and their correction by DNA repair systems have been recognised as important subjects in high school biology curricula (American Association for the Advancement of Science [AAAS], 1994; Barker, 1983; Lock, 1997). Unfortunately, in spite of the prevalence of UV radiation in our lives, most students have minimal awareness of it and the effects on living organisms (Morimoto,2002). UV radiation and its effect on DNA were found to be particularly difficult subjects to learn, and students found this material too abstract (Johnstone and Mahmoud, 1980; Hallden, 1988; Pashley, 1994; Bahar et al, 1999). Furthermore, research has shown that students find the micro level (cellular and molecular) difficult to understand (Marbach-Ad and Stavy, 2000). One reason for the difficulties students encounter is the fact that the micro levels are generally taught in a theoretical manner, while the processes and components at these levels cannot be touched or directly observed (Marbach-Ad and Stavy, 2000). Marbach-Ad and Stavy (2000) suggested that UV radiation damage and bacterial DNA repair systems This paper reports on a simple hands-on laboratory procedure for high school students in studying both radiation damage and DNA repair systems in bacteria. The sensitivity to ultraviolet (UV) radiation of both Escherichia coli and Serratia marcescens is tested by radiating them for varying time periods. Two growth temperatures are used in order to induce the production of the melanin-like pigment prodigiosin in Serratia marcescens. Several explanations are then suggested for the differences observed, including cellular DNA repair systems and the presence of the intracellular pigment prodigiosin. The experiment's results prove that the different sensitivities to radiation of both bacterial strains are caused by cellular DNA repair systems, and not by other cellular molecules, such as the pigment prodigiosin. The paper also suggests further laboratory investigations designed to enhance high school students' understanding of bacterial DNA repair systems.

Purpose: To determine the role of RLIP76 in providing protection from radiation and chemotherapy. In the present report, we used RLIP76 to refer to both the mouse (Ralbp1) and the human (RLIP76) 76-kDa splice variant proteins (RLIP76) for convenience and to avoid confusion. In other reports, Ralbp1 refers to the mouse enzyme (encoded by the Ralbp1 gene), which is structurally and functionally homologous to RLIP76, the human protein encoded by the human RALBP1 gene. Methods and Materials: Median lethal dose studies were performed in RLIP76 À/À and RLIP76 +/+ C57B mice after treatment with a single dose of RLIP76 liposomes 14 h after whole body radiation. The radiosensitivity of the cultured mouse embryonic fibroblasts and the effects of buthionine sulfoximine (BSO), amifostine, c-jun N-terminal kinase (JNK), protein kinase B (Akt), and MAPK/ERK kinase (MEK) were determined by colony-forming assays. Glutathione-linked enzyme activities were measured by spectrophotometric assays, glutathione by dithiobis-2nitrobenzoic acid (DTNB), lipid hydroperoxides by iodometric titration, and aldehydes and metabolites by thiobarbitauric acid reactive substances and liquid chromatography-mass spectrometry (LCMS). Results: RLIP76 À/À mice were significantly more sensitive to radiation than were the wild-type, and RLIP76 liposomes prolonged survival in a dose-dependent manner in both genotypes. The levels of 4-hydroxynonenal and glutathione-conjugate of 4-hydroxynonenal were significantly increased in RLIP76 À/À tissues compared with RLIP76 +/+ . RLIP76 À/À mouse embryonic fibroblasts were markedly more radiosensitive than RLIP76 +/+ mouse embryonic fibroblasts, despite increased glutathione levels in the former. RLIP76 augmentation had a remarkably greater protective effect compared with amifostine. The magnitude of effects of RLIP76 loss on radiation sensitivity was greater than those caused by perturbations of JNK, MEK, or Akt, and the effects of RLIP76 loss could not be completely compensated for by modulating the levels of these signaling proteins. Conclusion: The results of our study have shown that RLIP76 plays a central role in radiation resistance. Ó 2008 Elsevier Inc.

The effect of combining low-dose irradiation (1.75 kGy) with modified atmosphere packaging (MAP) on the microbiological and sensory quality of pork chops stored at refrigeration temperatures was studied. The microflora of irradiated MAP pork was almost exclusively composed of lactic acid bacteria, predominantly Lactobacillus spp. Modified atmospheres containing either 25 or 50% CO2, balance N2, resulted in the best microbial control in irradiated pork held at 4°C, compared to an unirradiated MAP control, and these atmospheres were subsequently used in sensory studies. The atmosphere containing 25% CO2 75% N2 maintained the uncooked colour and odour of irradiated pork chops more effectively than 50% CO2 50% N2. Therefore packaging in a modified atmosphere containing 25% CO2, balance N2, followed by irradiation to a dose of 1.75 kGy is recommended to improve the microbiological and sensory quality of pork chops.

Matrix glass composition for a possible immobilization of radioactive waste is selected. Borosilicate glass is low-alkali and relatively low-melting. It has a sufficiently high initial chemical resistance. To improve radiation chemical resistance was used such additives: oxides of cerium, iron, and manganese. After irradiation by quantum's (Co 60 ) with high-dose exposure, samples were tested for chemical resistance against water action. Experiments demonstrated the effectiveness of such additives.

Laser-produced plasmas (LPP) are laboratory-scale, table-top and high-brightness sources of partially coherent radiation that can be tuned between the extreme ultraviolet and the hard X-rays. A few LPP emission wavelengths find important applications in bio-photonics. As an example, LPP emitting in the so called “water window” (spectral range λ= 4.4 nm – 2.3 nm) allowed the world first X-ray scanning microscopy and contact microscopy, the latter being able to perform in vivo molecules imaging with 50-nm spatial resolution.

Radiation hardness is tested for 4H-SiC n-p-n bipo- lar junction transistors designed for 1200-V breakdown voltage by implanting MeV protons and carbon ions at different doses and energies. The current gain is found to be a very sensitive parameter, and a fluence as low as 1 × 107 cm−2 of 10 MeV 12C can be clearly detected in the forward-output characteristics, IC (VCE). At this low dose, no influence of ion radiation is seen in the open-collector characteristics, IB (VEB), or the reverse bias leakage and breakdown properties. Moreover, by annealing the implanted devices at 420 ◦C for 30 min, a complete recovery of the electrical characteristics is accomplished.

This paper introduces a modified enhanced transmission-line theory to account for higher-order modes while using a standard transmission line equation solver or equivalently a Baum, Liu and Tesche (BLT) equation solver. The complex per-unit-length parameters as defined by Nitsch et al. are first cast into an appropriate per-unit-length resistance, inductance, capacitance and conductance (RLCG) form. Besides, these per-unit-length parameters are modified to account for radiation losses with reasonable approximations. This modification is introduced by an additional per-unit-length resistance. The reason and explanations for this parameter are provided. Results obtained with this new formalism are comparable to those obtained using an electromagnetic full-wave solver, thus extending the capability of conventional transmission line solvers.

The work reported here represents a study into the total fluorescence exhibited by a broad selection of model, extremophilic and photosynthetic bacterial strains, over a great range of excitation and emission wavelengths from ultraviolet (UV) through visible to near infrared. The aim is to identify distinctive fluorescent features that may serve as detectable biosignatures of remnant microbial life on the Martian surface. A lab-bench fluorescence spectrometer was used to generate an excitation–emission matrix (EEM) for the unpigmented Escherichia coli, radiation-resistant Deinococcus radiodurans, Antarctic Dry Valley isolates Brevundimonas sp. MV.7 and Rhodococcus sp. MV.10, and the cyanobacterium Synechocystis sp. PCC 6803. Detailed EEMs, representing the fluorescence signature of each organism, are presented, and the most significant features suitable for biosignature surveys are identified, including small-molecule cellular metabolites, light-harvesting photosynthetic pigments an...

The radiation impedance of a capacitive micromachined ultrasonic transducer (cMUT) with a circular membrane is calculated analytically using its velocity profile for the frequencies up to its parallel resonance frequency for both the immersion and the airborne applications. The results are verified by finite element simulations. The work is extended to calculate the radiation impedance of an array of cMUT cells positioned in a hexagonal pattern. A higher radiation resistance improves the bandwidth as well as the efficiency of the cMUT. The radiation resistance is determined to be a strong function of the cell spacing. It is shown that a center-to-center cell spacing of 1.25 wavelengths maximizes the radiation resistance, if the membranes are not too thin. It is also found that excitation of nonsymmetric modes may reduce the radiation resistance in immersion applications.

In this study, the mechanism for the unique minority-carrier injection-enhanced annealing phenomena and the origin of the major radiation-induced defect in InGaP top cell materials are discussed in comparison with InP. The optimal design for the InGaP base layer thickness of the InGaP/GaAs 2-junction cells for current matching at EOL is examined. It is also found that the radiation tolerance of InGaP/middle cell/Ge 3-junction tandem solar cells can be improved by thinning the InGaP top cell layer thickness, by reducing base layer carrier concentration of the GaAs bottom cells, and by looking for radiation-resistant middle cell materials.

This paper describes various reliability concerns of the newly developed INGRID detector. This radiation detector is fabricated by waferscale CMOS post-processing; fresh detectors show excellent performance. Since the microsystems will be used unpackaged they are susceptible to all kinds of environmental conditions. The device passed tests of micro-ESD, radiation hardness, dielectric strength; but humidity tests show one weakness of SU-8 as a structural material. Already after 1 day of exposure to a humid condition the structural integrity, as measured by a shear stress test, is dramatically lowered. Dry storage of these devices is therefore a necessity. KMPR photoresist shows promising results as an alternative structural material.

Blending cyanate ester (CE) with epoxy resins offers the possibility to manufacture radiation resistant insulations at a low price compared to pure CE materials. Therefore, it is of special interest to study the influence of the CE content and also the effect of catalyst on the curing ...

Renal cell carcinoma (RCC) is often regarded as a radiation-resistant tumor. However, radiation therapy (RT) in the form of stereotactic radiosurgery (SRS) or whole-brain irradiation has been used to treat brain metastases from RCC. To date, there have been no clinical pathologic correlative findings before and after RT. Herein, we present a case of a patient with brain metastases from RCC treated with SRS. The diagnosis of clear-cell RCC was made in 2001 after right radical nephrectomy. He was also found to have lung metastases at diagnosis. He presented with neurologic symptoms in 2004, and magnetic resonance imaging showed 3 brain lesions with a significant amount of edema consistent with brain metastases. The largest lesion caused a midline shift and was surgically resected. Pathology revealed metastatic RCC. The other 2 smaller brain lesions were treated at 20 Gy respectively with shaped-beam SRS using the BrainLab Novalis ® system. No whole-brain irradiation was delivered. However, the patient had difficulty weaning off his steroids, and a magnetic resonance imaging performed 6 months after SRS was read as "progression of the lesions." He then underwent resection of both the irradiated brain lesions. Pathologic examination revealed necrotic tissues without any viable tumor identified. The patient has since been doing very well, now 18 months after SRS and 5 years from the initial diagnosis. This is the first reported case that demonstrates that precise high-dose radiation in the form of SRS can cause significant tumor cell death (pathologic complete response) in radiation-resistant brain metastases from RCC. This finding also provides a rationale to deliver stereotactic body RT for primary and metastatic RCC extracranially. A prospective clinical trial using stereotactic body RT for primary and metastatic RCC is under way.

(Accepted: 5 May 2004) Abstract. To assess the impact of UV-B radiation combined with NaHSO3 in solution under lab-oratory conditions, we compared the amounts of stress-ethylene produced by two lichen species of the same genus. Ramalina lacera, an epiphytic Mediterranean ...

Dispersoid strengthening is particularly important for ferritic based structural components used in nuclear applications due to their superior radiation resistance and creep strength at high temperatures. Within nuclear technologies yttrium particles dispersed throughout the matrix are the most promising ferritic steels to achieve these improved materials properties by acting as obstacles to dislocation motion. Due to radiation damage in these alloys considerable production of helium bubbles can be observed. Their amalgamation into large structures can be detrimental to the material's lifetime and it is therefore important to understand how their interaction with other defects can be controlled and what effect their presence has. Increased computational power now allows the direct study of such dislocation-obstacle interactions using 3D Discrete Dislocation Dynamics simulations at the mesoscale. In this work the effect of helium bubbles in irradiated dispersion strengthened ferritic steels and the response of the critical resolved shear stress is studied and found to increase with the density of helium bubbles.

A novel method of using artificial neural networks (ANNS) for the calculation of the radiation resistance of a coax-fed rectangular microstrip antenna is presented in this Letter. The network is trained with the results of three different antennas and tested for the fourth antenna. The tested results are in very good agreement. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 51–53, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10370

Electron microscopic studies of polymers are limited due to beam damage. Two concerns are the damage mechanism in a particular material, and the maximum dose for a material before damage effects are observed. From the knowledge of the dose required for damage to the ...

Electrically-small antennas present high-Q impedances characterized by large reactances and small radiation resistances. For such antennas, the effectiveness of passive matching is severely limited by gain-bandwidth theory, which predicts narrow bandwidths and/or poor gain. With receivers, the inability to resolve this impedance mismatch results in poor signal-to-noise (S/N) ratio, as compared to using a full-size antenna. With transmitters, the consequence

New scintillating thin films with improved radiation hardness were synthesised for applications in the field of radiation monitoring, by dispersing Rhodamine B (RB) dye into a high radiation resistant polymeric matrix (6FDA-DAB polyimide). The radiation hardness and the scintillation efficiency of this new composite material were tested by means of ion beam induced luminescence (IBIL) and compared to thin films of the traditional NE102 plastic scintillator. The samples were irradiated by 2.0 MeV 4 He þ ion beam at fluences ranging between 10 12 and 10 15 ions/cm 2. IBIL results indicated that the polyimide-based scintillator has a better radiation hardness and a good scintillation efficiency for high doses irradiations.

Glioblastoma multiforme (GBM) is a highly invasive primary brain tumour that has poor prognosis despite aggressive treatment. A hallmark of these tumours is diffuse invasion into the surrounding brain, necessitating a multi-modal treatment approach, including surgery, radiation and chemotherapy. We have previously demonstrated the ability of our model to predict radiographic response immediately following radiation therapy in individual GBM patients using a simplified geometry of the brain and theoretical radiation dose. Using only two pre-treatment magnetic resonance imaging scans, we calculate net rates of proliferation and invasion as well as radiation sensitivity for a patient's disease. Here, we present the application of our clinically targeted modelling approach to a single glioblastoma patient as a demonstration of our method. We apply our model in the full three-dimensional architecture of the brain to quantify the effects of regional resistance to radiation owing to hy...

The radiation resistances of electrically small antennas are precisely measured on the basis of the Wheeler cap method, reducing drift error, which is due to thermal fluctuation of components of a network analyser, by using a double-stub tuner. For the first time in antenna measurements, quantitative consideration of the reduction or the drift error for the network analyser is conductcd. Also, time fluctuation of the drift error is characterised with a vector diagram to find an effective method for the drift error reduction. As a result, the ineasuremcnt precision of the antenna with a very large input reactance (niore than 18OQ in its absolute value) is considerably improved using the stub tuner.

... current in each sub-cell as a function of 1 MeV electron fluence; the ... the open symbols represent a lightweight panel technology where the cell weight is the dominant factor ... In a mechanical stackconfiguration, an In0448Ga0452P/GaAs/In0453Ga0447 As device holds the world ...

A new theoretical model is presented in which the radiation-induced zero-resistance states and resistivity oscillations are analyzed. The basis of our model is an exact solution for the harmonic oscillator wave function in the presence of radiation and a perturbation treatment for elastic scattering due to randomly distributed charged impurities. Following this model most experimental results are reproduced: zero-resistance states, resistivity oscillations and the dependence of resistivity with temperature, where a physical model of interaction with acoustic phonon is presented, and an activation energy is calculated.

Radiation hardness is tested for 4H-SiC n-p-n bipolar junction transistors designed for 1200-V breakdown voltage by implanting MeV protons and carbon ions at different doses and energies. The current gain is found to be a very sensitive parameter, and a fluence as low as 1 × 10 7 cm −2 of 10 MeV 12 C can be clearly detected in the forward-output characteristics, I C (V CE ). At this low dose, no influence of ion radiation is seen in the open-collector characteristics, I B (V EB ), or the reverse bias leakage and breakdown properties. Moreover, by annealing the implanted devices at 420 • C for 30 min, a complete recovery of the electrical characteristics is accomplished.