Frequency dispersion reduction and bond conversion on n-type GaAs by in situ surface oxide removal and passivation

The method of surface preparation on n-type GaAs, even with the presence of an amorphous-Si interfacial passivation layer, is shown to be a critical step in the removal of accumulation capacitance frequency dispersion. In situ deposition and analysis techniques were used to study different surface preparations, including NH4OH, Si-flux, and atomic hydrogen exposures, as well as Si passivation depositions prior to in situ atomic layer deposition of Al2O3. As–O bonding was removed and a bond conversion process with Si deposition is observed. The accumulation capacitance frequency dispersion was removed only when a Si interlayer and a specific surface clean were combined

GaAs interfacial self-cleaning by atomic layer deposition

The reduction and removal of surface oxides from GaAs substrates by atomic layer deposition (ALD) of Al2O3 and HfO2 are studied using in situ monochromatic x-ray photoelectron spectroscopy. Using the combination of in situ deposition and analysis techniques, the interfacial "self-cleaning" is shown to be oxidation state dependent as well as metal organic precursor dependent. Thermodynamics, charge balance, and oxygen coordination drive the removal of certain species of surface oxides while allowing others to remain. These factors suggest proper selection of surface treatments and ALD precursors can result in selective interfacial bonding arrangements

In-situ characterization of Ga2O passivation of In0.53Ga0.47As prior to high-k dielectric atomic layer deposition

Ga2O interfacial passivation layers (IPLs) on In0.53Ga0.47As are investigated using in-situ monochromatic x-ray photoelectron spectroscopy. The oxide is entirely composed of Ga2O when deposited with an effusion cell temperature of 1500 degrees C and substrate temperature of 425 degrees C. The growth on In0.53Ga0.47As reveals slight chemical modification of the surface. The Ga2O behavior and ability to protect the III-V surface are observed following Al2O3 deposition by atomic layer deposition following each precursor pulse. Al2O3 growth by trimethyl-Al (TMA) and water reveals that the IPL undergoes the "clean-up" effect following TMA exposures causing As-As bonding formation resulting in a high interface state density. (C) 2011 American Institute of Physics. (doi:10.1063/1.3615666

A systematic study of (NH4)(2)S passivation (22%, 10%, 5%, or 1%) on the interface properties of the Al2O3/In0.53Ga0.47As/InP system for n-type and p-type In0.53Ga0.47As epitaxial layers

In this work, we present the results of an investigation into the effectiveness of varying ammonium sulphide (NH4)(2)S concentrations in the passivation of n-type and p-type In0.53Ga0.47As. Samples were degreased and immersed in aqueous (NH4)(2)S solutions of concentrations 22%, 10%, 5%, or 1% for 20 min at 295 K, immediately prior to atomic layer deposition of Al2O3. Multi-frequency capacitance-voltage (C-V) results on capacitor structures indicate that the lowest frequency dispersion over the bias range examined occurs for n-type and p-type devices treated with the 10% (NH4)(2)S solution. The deleterious effect on device behavior of increased ambient exposure time after removal from 10% (NH4)(2)S solution is also presented. Estimations of the interface state defect density (D-it) for the optimum 10% (NH4)(2)S passivated In0.53Ga0.47As devices extracted using an approximation to the conductance method, and also extracted using the temperature-modified high-low frequency C-V method, indicate that the same defect is present over n-type and p-type devices having an integrated D-it of similar to 2.5 x 10(12) cm(-2) (+/- 1 x 10(12) cm(-2)) with the peak density positioned in the middle of the In0.53Ga0.47As band gap at approximately 0.37 eV (+/- 0.03 eV) from the valence band edge. Both methods used for extracting D-it show very good agreement, providing evidence to support that the conductance method can be applied to devices incorporating high-k oxides on In0.53Ga0.47As. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3533959

Tony Coleing : collaborative prints

Tony Coleing : collaborative prints Catalogue to accompany an exhibition held at the Plimsoll Gallery, 24th July to 15th August 1993 curated by Milan Milojevic ; artists statements by Leigh Hobba and Bob Jenyn

Acute aortic dissection in a patient with Marfan syndrome during advanced pregnancy

Pregnant patients with Marfan syndrome (MFS) are at high risk of developing aortic dissection or rupture during the third trimester and early postpartum period. This increased likelihood is the consequence of the hyperdynamic and hypervolemic cardiocirculatory state and/or pregnancy-mediated structural changes of the arterial wall in response to hemodynamic and hormonal changes. In this article, we report on the case of a 26-year-old pregnant woman with MFS in the 30th gestation w

Detection and quantification of hepatitis e virus genome in pig liver samples originating from Serbian retail establishments

Hepatitis E is considered an emerging human viral disease with a zoonotic nature, and domestic and wild pigs are the main reservoirs of hepatitis E virus (HEV) among animals. Pork liver is the target tissue of this virus. This study aimed to investigate the presence of HEV in commercial pig liver samples. Sixty samples were collected during one year from different retail outlets in Serbia. Furthermore, the collected samples were separated by four seasons, and every season included three months. The presence of HEV in the livers was examined by molecular analysis using RT-qPCR. The overall prevalence of the virus in analysed pig livers was 5%. HEV was detected in three livers, two in the first season and one in the second, while in the third and fourth season, no positive livers were detected. However, there were no statistically significant differences between the surveyed seasons. HEV was quantified in positive livers. Among positive livers, HEV concentrations ranged between 8×101 and 1.9×104 genome copies of the virus per gram. The presence of HEV in commercial pig livers indicates a potential risk for consumers. Appropriate heat treatment of meals during preparation is essential to eliminate the potential risk of developing the illness. © Published under licence by IOP Publishing Ltd

2017 EACTS/EACTA Guidelines on patient blood management for adult cardiac surgery

Authors/Task Force Members: Christa Boer (EACTA Chairperson)(Netherlands), Michael I. Meesters (Netherlands), Milan Milojevic (Netherlands), Umberto Benedetto (UK), Daniel Bolliger (Switzerland), Christian von Heymann (Germany), Anders Jeppsson (Sweden), Andreas Koster (Germany), Ruben L. Osnabrugge (Netherlands), Marco Ranucci (Italy), Hanne Berg Ravn (Denmark), Alexander B.A. Vonk (Netherlands), Alexander Wahba (Norway), Domenico Pagano (EACTS Chairperson)(UK),. Document Reviewers: Moritz W.V. Wyler von Ballmoos (USA), Mate Petricevic (Croatia), Arie Pieter Kappetein (Netherlands), Miguel Sousa-Uva (Portugal), Georg Trummer (Germany), Peter M. Rosseel (Netherlands), Michael Sander (Germany), Pascal Colson (France), Adrian Bauer (Germany)

Landfall : an exhibition of hand-pulled lithographs printed at Landfall Press, Chicago

This exhibition represents a selection of printers' proofs on which Milan Milojevic worked, as apprentice printer at Landfall

Impact of concomitant aortic regurgitation on long-term outcome after surgical aortic valve replacement in patients with severe aortic stenosis

<p>Abstract</p> <p>Background</p> <p>Prognostic value of concomitant aprtic regurgitation (AR) in patients operated for severe aortic stenosis (AS) is not clarified. The aim of this study was to prospectively examine the impact of presence and severity of concomitant AR in patients operated for severe AS on long-term functional capacity, left ventricular (LV) function and mortality.</p> <p>Methods</p> <p>Study group consisted of 110 consecutive patients operated due to severe AS. The patients were divided into AS group (56 patients with AS without AR or with mild AR) and AS+AR group (54 patients with AS and moderate, severe or very severe AR). Follow-up included clinical examination, six minutes walk test (6MWT) and echocardiography 12 and 104 months after AVR.</p> <p>Results</p> <p>Patients in AS group had lower LV volume indices throughout the study than patients in AS+AR group. Patients in AS group did not have postoperative decrease in LV volume indices, whereas patients in AS+AR group experienced decrease in LV volume indices at 12 and 104 months. Unlike LV volume indices, LV mass index was significantly lower in both groups after 12 and 104 months as compared to preoperative values. Mean LVEF remained unchanged in both groups throughout the study. NYHA class was improved in both groups at 12 months, but at 104 months remained improved only in patients with AS. On the other hand, distance covered during 6MWT was longer at 104 months as compared to 12 months only in AS+AR group (p = 0,013), but patients in AS group walked longer at 12 months than patients in AS+AR group (p = 0,002). There were 30 deaths during study period, of which 13 (10 due to cardiovascular causes) in AS group and 17 (12 due to cardiovascular causes) in AS+AR group. Kaplan-Meier analysis showed that the survival probability was similar between the groups. Multivariate analysis identified diabetes mellitus (beta 1.78, p = 0.038) and LVEF < 45% (beta 1.92, p = 0.049) as the only independent predictor of long-term mortality.</p> <p>Conclusion</p> <p>Our data indicate that the preoperative presence and severity of concomitant AR has no influence on long-term postoperative outcome, LV function and functional capacity in patients undergoing AVR for severe AS.</p