Bias and temperature dependence of homogeneous hot-electroninjection from silicon into silicon dioxide at low voltages

In this paper, new homogeneous hot-electron injection data at 300 K and 77 K is provided covering applied voltages from well below to well above the Si-SiO₂ barrier height, and a wide range of oxide fields. We found that, in contrast to the MOSFET case, homogeneous injection shows two different regimes for accelerating voltages below and above the barrier height. A simple interpretation of the data is proposed, and supported by Monte Carlo (MC) simulations of the injection experiment. Essentially, the two regimes are the signature of a marked transition between an electron population mostly heated by the electric field, and a tail population created by additional but less efficient energy gain mechanisms, leading to a sharp transition in the carrier distribution function. The details of the bias and temperature dependence of injection are then interpreted as the combined effect of tunneling and carrier distribution. Furthermore, possible implications on MOSFET gate currents are briefly discussed     

Creutzfeldt-Jakob disease in a husband and wife

A 53-year-old man died of sporadic Creutzfeldt-Jakob disease (CJD) after a 1.5-year clinical course. Four and a half years later, his then 55-year-old widow died from CJD after a 1-month illness. Both patients had typical clinical and neuropathologic features of the disease, and pathognomonic proteinase-resistant amyloid protein ("prion" protein, or PrP) was present in both brains. Neither patient had a family history of neurologic disease, and molecular genetic analysis of their PrP genes was normal. No medical, surgical, or dietary antecedent of CJD was identified; therefore, we are left with the unanswerable alternatives of human-to-human transmission or the chance occurrence of sporadic CJD in a husband and wife.     

Surgery of inguinal hernia: our experience

The study is based on 848 patients that had surgery for inguinal hernia from January 1990 to May 1996. It compares the results obtained using the traditional plastic, called "direct suture", with the results of plastics with prosthesis. A special attention is given to tension-free techniques carried in local anesthesia, undoubtedly considered advantageous because of the technical simplicity in association with the total absence of postoperative complications and relapses, when correctly executed.     

DTG combustion behaviour of charcoals

In this paper, data are reported for the behaviour of some charcoals during combustion and devolatilization in a thermal analyser.     

Injection efficiency of CHISEL gate currents in short MOS devices:physical mechanisms, device implications, and sensitivity totechnological parameters

This paper analyzes MOSFET gate currents in the so-called channel initiated secondary electron injection regime (CHISEL). A Monte Carlo model of the phenomenon is validated and then extensively used to explore CHISEL scaling laws. Results indicate that, compared to conventional channel hot electron injection (CHE), CHISEL exhibits a weaker dependence on channel length and a larger sensitivity to short channel effects. These results are confirmed experimentally and exhaustively explained with the help of simulations; furthermore, some of their possible detrimental consequences on the programming efficiency of CHISEL based flash cells are analyzed. Finally, the impact of channel doping, oxide thickness, and junction depth on CHISEL efficiency has been explored, and guidelines to maintain high injection efficiency in short devices are derived     

Impact of interface and bulk trapped charges on transistor reliability

Oxide reliability is a key issue and the main topic of several recent works. We study the impact of gate oxide stress on transistor performances following a methodology similar to oxide lifetime characterisation in capacitors. A universal trend for degradation of the threshold voltage and drain saturation current with injected charge is observed and the impact of boron on trapping enhancement has been separated by comparing n-MOS and p-MOS.     

Coal combustion: Correlation between surface area and thermogravimetric analysis data

A series of coals of different rank has been characterized by surface area measurements performed by sorption of both nitrogen and carbon dioxide. While the data obtained with nitrogen do not discriminate among the different coal samples, those based on carbon dioxide sorption do give a significant distinction between the samples. This technique has also been applied to the determination of the surface area of coal samples quenched after stepwise combustion in air atmosphere. It has been possible to establish a useful correlation between the latter data and the burning profile measured by derivative thermogravimetry. The aim of the present study was to gain a better understanding of the coal combustion process on a laboratory scale which could reasonably be extended to combustion plants. The results presented are relevant to some of the multivalent aspects inherent in the coal combustion process and some valuable information has been gained in respect of characterization of solid fuels.     

Neuropathology of Gerstmann-Sträussler-Scheinker disease

Gerstmann-Str?ussler-Scheinker disease is a familial neurodegeneration characterized clinically by adult-onset ataxia, postural abnormalities, and cognitive decline, and pathologically by amyloid deposits mostly localized in the cerebral and cerebellar cortices and the basal ganglia. The disease is due to mutations in the prion protein gene. Processing of the mutant proteins originates the amyloidogenic fragments that accumulate in the tissue. PrP-immunoreactive amyloid deposits are the morphological hallmark of the disease. Hypertrophic astrocytes, activated microglia, and nerve cell loss are consistently associated with PrP-amyloid deposits, while spongiosis, diffuse PrP immunoreactivity, neurofibrillary tangles, Lewy bodies, and long fiber tracts degeneration are occasionally associated. The clinical and pathological variability observed in GSS families is related to both mutations and the M/V polymorphism at codon 129 of the mutated gene.     

A rapid heating TGA method for evaluating the carbon residue of fuel oil

A new TGA method for evaluating the carbon residue of heavy fuel oil (TGCR) is proposed. Using a Netzsch STA 409 thermobalance it is possible to submit the sample to a high heating rate (> 750°C min⁻¹) in nitrogen obtaining a rapid pyrolysis followed by the combustion of carbon residue in oxygen. The results obtained for eight samples of heavy fuel oil are compared with the asphaltene content and with the Conradson carbon residue (CCR). This method is easy and rapid to carry out; it is characterized by good repeatability and may be widely employed in routine laboratories for fuel oil control.     

The teaching of clinical oncology in Italian medical schools. A survey among teachers and students

BACKGROUND: Oncologists, health care workers and health organizations consider well-performed teaching programs in clinical oncology a fundamental step in cancer control. The aim of our study was to assess the views of teachers and students on the present status of oncology teaching in Italian medical schools and on the most common shortcomings in cancer education. MATERIALS AND METHODS: A survey was carried out among teachers and students of 17 Italian medical schools using two different questionnaires. Six hundred forty-seven students of Northern, Central and Southern Italy in the final two years (5th and 6th) of their medical curriculum and 87 professors of pathology, surgery, internal medicine and medical oncology completed the questionnaires. RESULTS: Doctor/patient relationships and integration among disciplines were the most unsatisfactory aspects of oncology teaching, according to students. Biology, epidemiology, radiotherapy, and medical treatment were felt to be insufficiently treated, whilst diagnostic aspects, clinical management and surgery were rated sufficient. The median number of cancer patients to whom each student had access during his/her training was limited, averaging only 13 patients; however, a high degree of variability was noted. A larger number of patients was generally observed in smaller, less crowded medical schools, with notable exceptions. Although the majority of teachers had clinical practices related to their disciplines, only a small number of students underwent a period of clinical training. Traditional methods of teaching were preferred to innovative methods, while interaction among disciplines was uncommon. CONCLUSIONS: This survey emphasizes the dualism between students' expectations and teachers' ideas about cancer teaching. Doctor/patient relationships and poor attention to practical clinical problems seem the most critical issues for clinical oncology training in Italian medical schools.