A complete study of the defects created in the gate oxide and at the gate oxide/strate interface of metal-oxide-semiconductor transistors during ionizing radiation and hot carrier injection and the ...mechanisms responsible for these defects' creation have been given. In addition, the pMOS dosimeters and power metal-oxide-semiconductor field effect transistors as the samples are used.
We investigated the influence of gamma radiation of 50 Gy(H2O) on radiation-sensitive p-channel metal-oxide-semiconductor field-effect transistors with an Al gate (RADFETs) with gate oxide ...thicknesses of 400 and 1000 nm and gate voltages of 0 and 5 V. The obtained results showed that the sensitivity S at a given gate voltage increases with the square of the gate oxide thickness. After irradiation (IR), spontaneous annealing (SA) was performed at room temperature without voltage at the gate. We present the behaviors of fixed traps and switching traps, determined by the midgap technique, and that of fast switching traps, determined by the charge-pumping technique, during IR and SA. A very important characteristic of dosimetric transistors is fading, which represents the recovery of the threshold voltage of the irradiated RADFETs during SA. The maximum fading is about 15% after 9100 h, except for the RADFETs with a gate oxide thickness of 1000 nm and a gate voltage of 5 V, for which it is about 30%. A fitting equation for fading was proposed, which fitted the experimental fading values very well.
Columnar structured cesium iodide (CsI) scintillators doped with Thallium (Tl) have been used extensively for indirect x-ray imaging detectors. The purpose of this paper is to develop a methodology ...for systematic investigation of the inherent imaging performance of CsI as a function of thickness and design type. The results will facilitate the optimization of CsI layer design for different x-ray imaging applications, and allow validation of physical models developed for the light channeling process in columnar CsI layers. CsI samples of different types and thicknesses were obtained from the same manufacturer. They were optimized either for light output (HL) or image resolution (HR), and the thickness ranged between 150 and 600 microns. During experimental measurements, the CsI samples were placed in direct contact with a high resolution CMOS optical sensor with a pixel pitch of 48 microns. The modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) of the detector with different CsI configurations were measured experimentally. The aperture function of the CMOS sensor was determined separately in order to estimate the MTF of CsI alone. We also measured the pulse height distribution of the light output from both the HL and HR CsI at different x-ray energies, from which the x-ray quantum efficiency, Swank factor and x-ray conversion gain were determined. Our results showed that the MTF at 5 cycles/mm for the HR type was 50% higher than for the HL. However, the HR layer produces ∼36% less light output. The Swank factor below K-edge was 0.91 and 0.93 for the HR and HL types, respectively, thus their DQE(0) were essentially identical. The presampling MTF decreased as a function of thickness L. The universal MTF, i.e., MTF plotted as a function of the product of spatial frequency f and CsI thickness L, increased as a function of L. This indicates that the light channeling process in CsI improved the MTF of thicker layers more significantly than for the thinner ones.
To report the results of a surveillance study on surgical site infections (SSIs) conducted by the International Nosocomial Infection Control Consortium (INICC).
Cohort prospective multinational ...multicenter surveillance study.
Eighty-two hospitals of 66 cities in 30 countries (Argentina, Brazil, Colombia, Cuba, Dominican Republic, Egypt, Greece, India, Kosovo, Lebanon, Lithuania, Macedonia, Malaysia, Mexico, Morocco, Pakistan, Panama, Peru, Philippines, Poland, Salvador, Saudi Arabia, Serbia, Singapore, Slovakia, Sudan, Thailand, Turkey, Uruguay, and Vietnam) from 4 continents (America, Asia, Africa, and Europe).
Patients undergoing surgical procedures (SPs) from January 2005 to December 2010.
Data were gathered and recorded from patients hospitalized in INICC member hospitals by using the methods and definitions of the Centers for Disease Control and Prevention National Healthcare Safety Network (CDC-NHSN) for SSI. SPs were classified into 31 types according to International Classification of Diseases, Ninth Revision, criteria.
We gathered data from 7,523 SSIs associated with 260,973 SPs. SSI rates were significantly higher for most SPs in INICC hospitals compared with CDC-NHSN data, including the rates of SSI after hip prosthesis (2.6% vs. 1.3%; relative risk RR, 2.06 95% confidence interval (CI), 1.8-2.4; P < .001), coronary bypass with chest and donor incision (4.5% vs. 2.9%; RR, 1.52 95% CI, 1.4-1.6; P < .001); abdominal hysterectomy (2.7% vs. 1.6%; RR, 1.66 95% CI, 1.4-2.0; P < .001); exploratory abdominal surgery (4.1% vs. 2.0%; RR, 2.05 95% CI, 1.6-2.6; P < .001); ventricular shunt, 12.9% vs. 5.6% (RR, 2.3 95% CI, 1.9-2.6; P < .001, and others.
SSI rates were higher for most SPs in INICC hospitals compared with CDC-NHSN data.
Electrical breakdown in low pressure gases Pejovic, Momcilo M; Ristic, Goran S; Karamarkovic, Jugoslav P
Journal of physics. D, Applied physics,
05/2002, Letnik:
35, Številka:
10
Journal Article
Recenzirano
The paper presents the results of an investigation of the electrical breakdown in low pressure gases when the secondary electrons released from the cathode play the dominant role in the initiation of ...electrical breakdown. The secondary electrons are created by the charged and neutral species formed during the previous breakdown and discharge as well as by gamma-rays. Electrical breakdown investigations are based on the measurements of electrical breakdown voltage and electrical breakdown time delay for gas-filled tubes with spherical electrodes with diameters much larger than an interelectrode distance. Stochastic nature of both the breakdown voltage and time delay are discussed, and their distributions based on experimental data are shown. The methods for the determination of static breakdown voltage are also analyzed. The influence of different parameters (overvoltage, cathode material and its surface purity, gas pressure, glow current, etc) on time delay are studied. Special attention is paid to the memory effect in various gases that depends on the positive ion recombination times, catalytic recombination times in the case of nitrogen and hydrogen, as well as metastable states deexcitation times in noble gases. The analysis of this effect is done by memory curves on the basis of which the presence of long-lived neutral active states can be followed to their very low concentrations when cosmic and environment radiation play the dominant role in electrical breakdown initiation. (Author)
We report different immunological phenotypes in three siblings from consanguineous family with recombinase‐activating gene 1 (RAG1) gene mutations. Null mutations of RAG genes result in severe ...combined immunodeficiency (SCID) with absent T and B cells. Hypomorphic mutations with retained activity of RAG genes may lead to a ‘leaky’ SCID with some features of Omenn syndrome (OS) or typical OS. In our three patients, homozygous, hypomorphic RAG1 gene mutation (g.368–369delAA) was detected. Two patients presented with T−B−SCID phenotype while the youngest patient developed T+B+NK+SCID phenotype with expansion of autologous T‐cell receptor (TCR) γδ‐positive T cells, increased immunoglobulin levels and retained ability for antibody production. Similar to originally reported patients with this newly recognized immune phenotype, our patient developed disseminated cytomegalovirus (CMV) infection and autoimmune cytopenia.
Conclusion: In infants with disseminated cytomegalovirus infection and autoimmune cytopenia, even if basic immunologic investigation appears normal, RAG1 immunodeficiency should be considered.
This paper describes the possibility of using an Electrically Programmable Analog Device (EPAD) as a gamma radiation sensor. Zero-biased EPAD has the lowest fading and the highest sensitivity in the ...300 Gy dose range. Dynamic bias of the control gate during irradiation was presented for the first time; this method achieved higher sensitivity compared to static-biased EPADs and better linear dependence. Due to the degradation of the transfer characteristics of EPAD during irradiation, a function of the safe operation area has been found that determines the maximum voltage at the control gate for the desired dose, which will not lead to degradation of the transistor. Using an energy band diagram, it was explained why the zero-biased EPAD has higher sensitivity than the static-biased EPAD.
To quantify the impact of inflammatory brain diseases in the pediatric population on health-related quality of life, including the subdomains of physical, emotional, school and social functioning.
...This was a multicenter, observational cohort study of children (< 18 years of age) diagnosed with inflammatory brain disease (IBrainD). Patients were included if they had completed at least one Health Related Quality of Life Questionnaire (HRQoL). HRQoL was measured using the Pediatric Quality of Life Inventory Version 4.0 (PedsQL) Generic Core Scales, which provided a total score out of 100. Analyses of trends were performed using linear regression models adjusted for repeated measures over time.
In this study, 145 patients were included of which 80 (55%) were females. Cognitive dysfunction was the most common presenting symptoms (63%), and small vessel childhood primary angiitis of the CNS was the most common diagnosis (33%). The mean child's self-reported PedsQL total score at diagnosis was 68.4, and the mean parent's proxy-reported PedsQL score was 63.4 at diagnosis. Child's self-reported PedsQL scores reflected poor HRQoL in 52.9% of patients at diagnosis. Seizures or cognitive dysfunction at presentation was associated with statistically significant deficits in HRQoL.
Pediatric IBrainD is associated with significantly diminished health-related quality of life. Future research should elucidate why these deficits occur and interventions should focus on improving HRQoL in the most affected subdomains, in particular for children presenting with seizures and cognitive dysfunction.
PDF
