P-channel MOSFET as ionizing radiation detector.

In this study, the authors examine the responses of radiation-sensitive p-channel MOSFETs to irradiation and subsequent annealing at room temperature and higher temperatures to investigate their use as a dosimeter for measuring ionizing radiation. The response of these transistors to radiation was monitored based on the shift in the threshold voltage as a function of the absorbed dose of radiation. The results showed that the shift in the threshold voltage depended on the densities of traps formed during exposure to ionizing radiation in Si and at the Si-SiO2 interface on which the charges were captured. We then analyzed the influence of these traps on the characteristics of the MOSFETs, and examined the influence of the gate bias, thickness of the gate oxide, energy of the ionizing radiation, and low doses on shifts in the threshold voltage. Moreover, we annealed the irradiated MOSFETs to determine their ability to preserve a certain dose of radiation over a long period as well as their potential for reuse. We explored the possibility of using commercial p-channel MOSFETs built into various electronic systems as sensors and dosimeters for measuring ionizing radiation. The results showed that they have approximately the same characteristics as radiation-sensitive MOSFETs with 100-nm-thick oxide layers.

Xenon-filled diode performance under influence of low doses of gamma radiation.

This paper presents a detailed statistical analysis of experimental results of dynamic breakdown voltage and electrical breakdown time delay for xenon-filled diode. These quantities have a stochastic nature and they were measured in the cases when the xenon-filled diode was and was not exposed to a gamma radiation source, with exposure dose rate 7.7⋅10-12 C/(kg⋅s). The static breakdown voltage was estimated based on dynamic breakdown voltage as a function of voltage increase rate. The applicability of certain distributions to experimental dynamic breakdown voltage and electrical breakdown time delay data was also analyzed.

Double unilateral fenestration of the anterior cerebral artery in the pre-communicating segment: a report of a unique case.

A unique example of two fenestrations of the pre-communicating (A1) segment of the right anterior cerebral artery (ACA) in a 78-year-old woman was a special case among 388 cadaveric specimens. It was found by a retrospective review of the personal data obtained during graduate and undergraduate studies at the Faculty of Medicine. Two unequal fenestrations of the right A1 segment were associated with the presence of a pseudo anterior communicating artery, hypoplasia of the right posterior communicating artery and the left superior cerebellar artery, absence of the right anterior inferior cerebellar artery, and ectasia of the basilar artery; however, the cerebral arteries were without aneurysm(s) or other pathology. The reason could be the almost equal ACA diameter on both sides.

Clinical and molecular characteristics of OXA-72-producing Acinetobacter baumannii ST636 outbreak at a neonatal intensive care unit in Serbia.

AIM: To describe an Acinetobacter baumannii outbreak among preterm neonates in a neonatal intensive care unit (NICU) in Serbia. METHODS: A case-control study was conducted in the NICU at the Institute of Neonatology, Belgrade, Serbia. The case definition of A. baumannii bloodstream infection (BSI) was blood culture confirmation of systemic infection. Isolation, identification and susceptibility testing were performed using conventional methods. Molecular characterization of isolates included resistance gene detection, pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. Outcomes and clinical and demographic data were obtained from patients' medical records. An infection prevention team was formed and infection control interventions were implemented. FINDINGS: During the outbreak period (May-July 2018), there were 13 cases of A. baumannii BSI among 82 hospitalized neonates. All A. baumannii strains were carbapenem resistant and susceptible to colistin. Molecular characterization of the isolates revealed that they harboured blaOXA66 and blaOXA72 beta-lactamases and belonged to sequence type 636, while the PFGE pattern indicated clonal spread. Lower gestational age, lower Apgar score, vaginal delivery and mechanical ventilation were risk factors for A. baumannii infection. Four patients died, eight patients were treated successfully with colistin, and one patient with sepsis and meningitis on dual ampicillin-sulbactam and colistin therapy recovered with sequelae. The outbreak was eventually controlled by reinforcement of the infection control measures based on a multi-tiered interventional approach. CONCLUSION: This is the first description of an outbreak of BSI among preterm neonates caused by A. baumannii blaOXA66/blaOXA72/ST636 in Serbia.

Zn- and (Mn, Zn)-substituted versus unsubstituted magnetite nanoparticles: structural, magnetic and hyperthermic properties.

In this work, we studied structural and magnetic properties of 18 nm sized Zn-substituted magnetite, 28 nm sized unsubstituted and 17 nm sized (Mn, Zn)-substituted iron oxide nanoparticles, synthesized by thermal decomposition method. Their features were examined by analyzing the x-ray diffraction data, 57Fe Mössbauer spectra and magnetization measurements by SQUID interferometer. The microstructure was inspected comparing the different size and strain broadening models incorporated into Fullprof software. In terms of crystallinity and size dispersion, applied synthesis protocol shows superiority over decomposition of iron oleate and the co-precipitation synthesis route. The saturation magnetization at T = 5 K was found to be within the M S = 91.2-98.6 A m2 kg-1 range, while at 300 K M S of pure and Zn-substituted Fe3O4 nanoparticles is 83.6 and 86.2 A m2 kg-1, respectively. Effective magnetic anisotropy constant K eff, estimated under slow measurements by SQUID, is below 20 kJ m-3 in all three samples. Some preliminary measurements of the magnetic hyperthermia performance, expressed via specific absorption rate value showed that the best heating performances were displayed by 18 nm sized oleic acid-coated Zn0.13Fe2.87O4 cubo-octahedrons with SAR â‰… 425 W/gFe at H 0 = 20 kA m-1 and f = 228 kHz.

Small dose effect in RADFET with thick gate oxide.

In order to track "small dose effect" leading to stabilization of RADFETs with 1 µm thick oxide fabricated at Tyndall National Institute, Cork, Ireland irradiation was performed with gamma-rays in the radiation dose interval from 1 to 5 cGy, followed with room temperature annealing for the time of 28 days. Gate bias during irradiation was 0, 2.5 and 5 V. Threshold voltage shift ΔVT determined from transfer characteristics in saturation were followed during irradiation and annealing. It was shown that there is significant increase in ΔVT for 1 cGy radiation dose and those are 36.3, 43.3 mV and 45.7 mV for gate bias 0, 2.5 V and 5 V, respectively. For higher radiation doses ΔVT also increases, however, such increase is much lower. RADFETs fading at room temperature lead to permanent decrease in ΔVT and after 28 days the threshold voltage for devices is returned to virgin device value. Small dose effect is confirmed and radiation dose of at least 5 cGy is necessary for RADFET stabilization before their use in dosimetric application. After RADFETs stabilization they were irradiated in dose interval from 10 to 50 cGy with gate bias of 0, 2.5 and 5 V. It was shown that there is a linear dependence between ΔVT and absorbed radiation dose D, for gate bias during irradiation 0, 2.5 and 5 V. Defects responsible for threshold voltage shift, formed during irradiation as well as their neutralization/compensation during annealing, are also discussed.

The Influence of the Magnetic Field on DC and the Impulse Breakdown of Noble Gases.

Increased electromagnetic contamination of the environment accompanied with the amplified miniaturization of electronic components underline the issue of the reliable operation of electronics. Reliability is of utmost importance in special applications such as medical instruments, nuclear installations, fusion experiments, etc., where larger magnetic fields occur during operation. Therefore, the interest for insulation components that consistently protect instrumentation from overvoltage is growing. This paper deals with the effects important for the stability of a gas surge arrester, the most commonly used low-voltage component for the overvoltage protection. The effect of the magnetic field on DC and the impulse breakdown of noble gases is investigated. For the theoretical interpretation of the obtained results, the spectrum of free electron gas was determined, which enabled the evaluation of a new expression for the first Townsend coefficient. The results obtained in that way were verified through comparison with theoretically calculated results. Experiments were carried out under well-controlled laboratory conditions.

VDMOSFET as a prospective dosimeter for radiotherapy.

Performance of a commercial p-channel power vertical-double-diffusion metal-oxide-semiconductor field-effect transistors (VDMOSFETs) as a γ-radiation dosimeters were studied. The devices were irradiated with 60Co to 10-50Gy at the gate biases ranging from 0 to 5V, and subsequent dosimetric signal fading was monitored during room-temperature storage without a gate bias for 100 days. A linear relationship was found between the threshold voltage shift and the radiation dose for all values of the gate bias. Furthermore, a power-law relationship between the radiation sensitivity and the gate bias during the irradiation was revealed. The radiation sensitivity of these devices is higher than that of RADFETs with 100-nm-thick oxide gate layers manufactured by the Tyndall National Institute in Cork, Ireland. Room-temperature signal fading for VDMOSFETs is similar to that for RADFETs, i.e., the threshold voltage shift decreases slowly. A continuous annealing of VDMOSFETs at 150°C for 27 days results in a significant decrease of the threshold voltage shift, especially during the first 7 days.

Anthropometric and physical characteristics allow differentiation of young female volleyball players according to playing position and level of expertise.

The aim of our study was to determine the differences in some anthropometric and physical performance variables of young Croatian female volleyball players (aged 13 to 15) in relation to playing position (i.e., independent variable) and performance level within each position (i.e., independent variable). Players were categorized according to playing position (i.e., role) as middle blockers (n=28), opposite hitters (n=41), passer-hitters (n=54), setters (n=30), and liberos (n=28). Within each position, players were divided into a more successful group and a less successful group according to team ranking in the latest regional championship and player quality within the team. Height and body mass, somatotype by the Heath-Carter method, and four tests of lower body power, speed, agility and upper body power (i.e., dependent variables) were assessed. Players in different positions differed significantly in height and all three somatotype components, but no significant differences were found in body mass, body mass index or measured physical performance variables. Players of different performance level differed significantly in both anthropometric and physical performance variables. Generally, middle blockers were taller, more ectomorphic, less mesomorphic and endomorphic, whereas liberos were shorter, less ectomorphic, more mesomorphic and endomorphic than players in other positions. More successful players in all positions had a lower body mass index, were less mesomorphic and endomorphic, and more ectomorphic than less successful players. Furthermore, more successful players showed better lower body power, speed, agility and upper body power. The results of this study can potentially provide coaches with useful indications about the use of somatotype selection and physical performance assessment for talent identification and development.

Sensitivity and fading of pMOS dosemeters irradiated with X-ray radiation doses from 1 to 100 cGy.

In this paper, the results of pMOS dosemeters sensitivity to X-ray radiation and 28-d fading at room temperature are presented. Two types of dosemeters were used, which differ in gate oxide layer thickness. The sensitivity of pMOS dosemeters with gate oxide layer thickness of 1 µm was followed in the dose intervals of 1 to 10 cGy and 10 to 100 cGy, whereas that of 400 nm was in the interval of 10 to 100 cGy. The sensitivity was characterised by the threshold voltage shift, which was determined as a function of absorbed radiation dose and time after irradiation. Linear dependence between threshold voltage shift and absorbed radiation dose was established, as well as that considerable fading occurs during the first few days after irradiation. The mechanisms responsible for threshold voltage shift during irradiation and latter annealing have been also discussed.

Dose response, radiation sensitivity and signal fading of p-channel MOSFETs (RADFETs) irradiated up to 50 Gy with 6°Co.

This paper reports response of p-channel MOSFETs (RADFETs) to (60)Co gamma radiation in the 10-50 Gy dose range and signal fading (room temperature annealing) for 100 days after irradiation. RADFETs with three different thicknesses of the gate oxide layer were used. Irradiations were performed at gate biases ranging from 0 to 5 V. Threshold voltage shift was monitored during the irradiations and the subsequent fading. The dependence of the threshold voltage shift on the radiation dose is linear for the RADFETs with 100 nm- and 400 nm-thick gate oxide layers irradiated under the gate biases ranging from 1.25 to 5 V. Also, an exponential dependence of the radiation sensitivity on the gate bias during irradiation was found. The signal fades at room temperature without a gate bias. The results demonstrate that these RADFETs are suitable as sensors of gamma radiation. The threshold voltage shift of the RADFETs with 400 nm- and 1 µm-thick gate oxide layers decreases significantly during the first day after irradiation, which, unfortunately, makes these devices incapable of holding dosimetric information for long periods of time.

Cholinergic receptors as target for cancer therapy in a systems medicine perspective.

Epithelial cells not innervated by cholinergic neurons express nicotinic and muscarinic acetylcholine (ACh) receptors (nAChR, mAChR). nAChR and mAChR are components of the auto-/paracrine-regulatory loop of non-neuronal ACh release. The cholinergic control of non-neuronal cells may be mediated by different effects (synergistic, additive, or reciprocal) triggered by these receptors. The ionic events (Ca(+2) influx) are generated by the ACh-opening of nAChR channels, while the metabolic events by ACh-binding to G-proteincoupled mAChR. Effective inter- and intracellular signaling is crucial for valuable cancer cells proliferation and survival. Depending on cancer cell type, different AChR have been identified. The proliferation of airways epithelial cancer cells and pancreatic cancer cells may be under the control of α7-nAChR and M3-mAChR, while breast cancer cells and colon cancer cells are regulated by α9-nAChR, and M3-mAChR, respectively. In turn, these receptors may activate different pathways (Ras-Raf-1-Erk-AKT) as well as other receptors (ß- adrenergicR). nAChR or mAChR antagonists may inhibit cancer growth. Inhibition of M3 by antisense or antagonists (Darifenacin, Tiotropium) reduces lung or colon cancer proliferation, as well as inhibition of α9- nAChR [polyphenol (-)-epigallocatechin-3-gallate] diminishes breast cancer cells growth. α7-nAChR silencing inhibits lung cancer proliferation. Moreover, inhibition of the nAChR-ß-adrenergicR pathway (ß-blockers) could be also useful. This review will describe the future translational perspectives of cholinergic receptors druginhibition in a complex disease such as cancer that poses compelling treatment challenges. Cancer happens as consequence of disease-perturbed molecular networks in relevant organ cells that change during progression. The framework for approaching these challenges is a systems approach.

Unusual suicide with a chainsaw.

A 39-year-old male, with a history of multiple suicidal attempts and psychiatric pathology, a professional lumberjack, was found dead at the meadow with his throat cut and a chainsaw beside him. Autopsy revealed that all physical injuries were confined to the head, neck and left shoulder. Two major (long and wide) wounds were found and documented on both sides of the neck and head. A wound on the posterior and right lateral side of his neck and head was noted. Medical examiner noted an irregular rupture on the posterior-right side of the atlanto-occipital joint with impaired bone, but without any damage on the spinal cord. Another gaping cut was noted in the lower part on the left lateral side of his neck. Medical examiner noted that muscles of the left side of the neck, left common carotid artery, left internal jugular vein and left vagus nerve were completely cut off. The body of the C5 and C6 vertebra, with the spinal cord at that level, was completely cut. Also, there were multiple linear and striped parallel abrasions on the outer side of the left shoulder and one abrasion on the left lateral side of the neck. The conclusion of inquiries was "suicide by chainsaw".

Response of pMOS dosemeters on gamma-ray irradiation during its re-use.

Response of pMOS dosemeters during two successive irradiations with gamma-ray irradiation to a dose of 35 Gy and annealing at room and elevated temperature has been studied. The response was followed on the basis of threshold voltage shift, determined from transfer characteristics, as a function of absorbed dose or annealing time. It was shown that the threshold voltage shifts during first and second irradiation for the gate bias during irradiation of 5 and 2.5 V insignificantly differ although complete fading was not achieved after the first cycle of annealing. In order to analyse the defects formed in oxide and at the interface during irradiation and annealing, which are responsible for threshold voltage shift, midgap and charge-pumping techniques were used. It was shown that during first irradiation and annealing a dominant influence to threshold voltage shift is made by fixed oxide traps, while at the beginning of the second annealing cycle, threshold voltage shift is a consequence of both fixed oxide traps and slow switching traps.

Evaluation of genotoxic effects of lead in pottery-glaze workers using micronucleus assay, alkaline comet assay and DNA diffusion assay.

PURPOSE: We investigated genotoxic effects of occupational exposure to lead acetate in pottery-glaze ceramic workers. METHODS: The study was carried out in 30 exposed workers and 30 matched controls, to whom several biochemical parameters-the blood lead (B-Pb; range: exposed, 41.68-404.77; controls, 12-52) and cadmium (B-Cd) level, the activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), the level of vitamin B(12) and folate in serum-were measured. The genotoxic effects were evaluated by the alkaline comet assay, the DNA diffusion assay and micronucleus test in peripheral blood lymphocytes. RESULTS: Subjects exposed to lead had significantly higher B-Pb level and, consequently, increased values of tail intensity (TI), frequency of apoptotic and necrotic cells, and frequency of micronuclei (MN). In contrast, their activity of ALAD, the level of vitamin B(12) and folate in serum were significantly lower compared to controls. Poisson regression analysis showed a significant correlation of profession, duration of exposure, smoking, level of cadmium in blood, ALAD and EP with primary DNA damage. A majority of primary damage repairs in a short period after exposure to a genotoxic agent. In addition, the influence of gender and level of vitamin B(12) and folate in serum MN frequency in exposed group was observed. CONCLUSIONS: In this study, DNA diffusion and micronucleus test showed higher influence of tested parameters to DNA damage. The results indicate a need for concomitant use of at least two different biomarkers of exposure when estimating a genetic risk of lead exposure.

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices.

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

Mechanisms of modulation of experimental autoimmune encephalomyelitis by chronic Trichinella spiralis infection in Dark Agouti rats.

Trichinella spiralis is a helminth that provokes Th2 and anti-inflammatory type responses in an infected host. Our previous studies using Dark Agouti (DA) rats indicated that T. spiralis infection reduced experimental autoimmune encephalomyelitis (EAE) severity in rats. The aim of this study was to analyse the mechanisms underlying EAE suppression driven by T. spiralis infection. Reduced clinical and histological manifestations of the disease were accompanied by increased IL-4 and IL-10 production and decreased IFN-gamma and IL-17 production in draining lymph node cells. This indicates that T. spiralis infection successfully maintains a Th2 cytokine bias regardless of EAE induction. High IL-10 signifies parasite-induced anti-inflammatory and/or regulatory cell responses. Transfer of splenic T cell-enriched population of cells from T. spiralis-infected rats into EAE immunized rats caused amelioration of EAE and in some cases protection from disease development. This population of cells contained higher proportion of CD4(+) CD25(+) Foxp3(+) regulatory cells and produced high level of IL-10 when compared with uninfected rats.

Complications of sevoflurane-fentanyl versus midazolam-fentanyl anesthesia in pediatric cleft lip and palate surgery: a randomized comparison study.

Careful choice of anesthetic agents in pediatric patients reduces the frequency of anesthesia-related complications. The frequency and type of intraoperative and postoperative complications of sevoflurane-fentanyl versus midazolam-fentanyl anesthesia were compared in 140 consecutive children (aged 3 months to 10 years) undergoing cleft lip and palate repair. Midazolam-fentanyl anesthesia was induced with midazolam (0.05 mg/kg), fentanyl (0.005 mg/kg) and vecuronium (0.1mg/kg), and maintained with the same agents according to the defined parametars. Sevoflurane-fentanyl anesthesia was induced and maintained with sevoflurane (5-8 vol% and 0.8-1 vol%, respectively) in an oxygen/air mixture and supplemented with fentanyl (0.005 mg/kg). Both groups were comparable in basic demographic data, hemodynamic and respiratory parameters. Difficult intubation occurred in 6 of 76 children (midazolam-fentanyl group) and 4 of 64 children (sevoflurane-fentanyl group) (P=0.754). Ventricular extrasystole and bronchospasm occurred in one patient each in the sevoflurane-fentanyl group. Postoperatively, emergence agitation was observed in the sevoflurane-fentanyl group (17 cases; P<0.001); postoperative nausea and vomiting occurred in 2 children (midazolam-fentanyl group) and 3 children (sevoflurane-fentanyl group) (P=0.660). Midazolam-based anesthesia in children is safer than sevoflurane-based anesthesia regarding occurrence of emergence agitation.

Hemodialysis headache.

AIM: The aim of this study was to evaluate and analyze the incidence and features of headaches in patients undergoing hemodialysis. MATERIAL AND METHODS: In this prospective study 318 patients, 119 women and 199 men, undergoing chronic HD in four hemodialysis centers in Serbia, were questioned about their problems with headaches using a questionary designed according to the diagnostic criteria of the International Headache Classification of Headache Disorders (ICHD) from 2004. Patients were distributed in two groups according to the presence of hemodialysis headaches (HDH). The groups were compared regarding sex, age, duration of HD, primary diseases that lead to ESRD, arterial systolic and diastolic blood pressure (BP) and serum levels of hemoglobin, urea nitrogen, creatinine, sodium, potassium, calcium, phosphates, albumin, glucose and calcium-phosphate product. We also analyzed features of HDH. The results were statistically compared. RESULTS: Patients with HDH had significantly lower serum glucose, but higher serum phosphates and albumin than patients without headaches. Furthermore, HDH patients had higher calcium phosphate product and systolic blood pressure than non-HDH patients. Out of 318 patients included in the study, 21 (6.6%) patients had HDH. According to our results, HDH appeared more frequently in men, during the 3rd hour of HD in more than a half of the patients and lasted less then 4 h in the majority of HDH patients. In the majority of patients HDH was bilateral, non-pulsating, without associated symptoms and it appeared mostly during HD. Personal history was negative for primary headaches in all patients with HDH. CONCLUSION: We believe that the results of our investigation of more than 300 HD patients pointed to some biochemical changes, possibly implicated by pathophysiology of HDH and disclose some specific HDH features that might contribute to a better understanding of this secondary headache disorder.

Trichinella spiralis: modulation of experimental autoimmune encephalomyelitis in DA rats.

Helminth infection has a potent systemic immunomodulatory effect on the host immune response, which also affects the development of autoimmune diseases. We investigated the dose-dependent influence of Trichinella spiralis infection on experimental autoimmune encephalomyelitis (EAE). Our model of concomitant T. spiralis infection and EAE demonstrates that established infection of Dark Agouti (DA) rats with the parasite causes amelioration of the clinical course of induced EAE in a dose-dependent way. Infection with T. spiralis L1 stage muscle larvae (TSL1) reduced the severity of the autoimmune disease as judged by lower maximal clinical score, cumulative index, duration of illness and degree of mononuclear cell infiltration in T. spiralis infected animals compared to control, EAE-induced group. This study provides a valuable model of worm infection to investigate helminth-induced regulatory mechanisms for optimal benefit to the host.