Search

Background We describe a frugal approach (focusing on needs, performance, and costs) to manage a massive influx of COVID-19 patients with acute hypoxemic respiratory failure (AHRF) using the Boussignac valve protected by a filter (“Filter Frugal CPAP”, FF-CPAP) in and out the ICU. Methods (1) A bench study measured the impact of two filters with different mechanical properties on CPAP performances, and pressures were also measured in patients. (2) Non-ICU healthcare staff working in COVID-19 intermediate care units were trained with a video tutorial posted on a massive open online course. (3) A clinical study assessed the feasibility and safety of using FF-CPAP to maintain oxygenation and manage patients out of the ICU during a massive outbreak. Results Bench assessments showed that adding a filter did not affect the effective pressure delivered to the patient. The resistive load induced by the filter variably increased the simulated patient’s work of breathing (6–34%) needed to sustain the tidal volume, depending on the filter’s resistance, respiratory mechanics and basal inspiratory effort. In patients, FF-CPAP achieved pressures similar to those obtained on the bench. The massive training tool provided precious information on the use of Boussignac FF-CPAP on COVID-19 patients. Then 85 COVID-19 patients with ICU admission criteria over a 1-month period were studied upon FF-CPAP initiation for AHRF. FF-CPAP significantly decreased respiratory rate and increased SpO2. Thirty-six (43%) patients presented with respiratory indications for intubation prior to FF-CPAP initiation, and 13 (36%) of them improved without intubation. Overall, 31 patients (36%) improved with FF-CPAP alone and 17 patients (20%) did not require ICU admission. Patients with a respiratory rate > 32 breaths/min upon FF-CPAP initiation had a higher cumulative probability of intubation (p Conclusion Adding a filter to the Boussignac valve does not affect the delivered pressure but may variably increase the resistive load depending on the filter used. Clinical assessment suggests that FF-CPAP is a frugal solution to provide a ventilatory support and improve oxygenation to numerous patients suffering from AHRF in the context of a massive outbreak.

Background Intensive Care Units (ICU) have sometimes been overwhelmed by the surge of COVID-19 patients. Extending ICU capacity can be limited by the lack of air and oxygen pressure sources available. Transport ventilators requiring only one O2 source may be used in such places. Objective To evaluate the performances of four transport ventilators and an ICU ventilator in simulated severe respiratory conditions. Materials and methods Two pneumatic transport ventilators, (Oxylog 3000, Draeger; Osiris 3, Air Liquide Medical Systems), two turbine transport ventilators (Elisee 350, ResMed; Monnal T60, Air Liquide Medical Systems) and an ICU ventilator (Engström Carestation—GE Healthcare) were evaluated on a Michigan test lung. We tested each ventilator with different set volumes (Vtset = 350, 450, 550 ml) and compliances (20 or 50 ml/cmH2O) and a resistance of 15 cmH2O/l/s based on values described in COVID-19 Acute Respiratory Distress Syndrome. Volume error (percentage of Vtset) with P0.1 of 4 cmH2O and trigger delay during assist-control ventilation simulating spontaneous breathing activity with P0.1 of 4 cmH2O and 8 cmH2O were measured. Results Grouping all conditions, the volume error was 2.9 ± 2.2% for Engström Carestation; 3.6 ± 3.9% for Osiris 3; 2.5 ± 2.1% for Oxylog 3000; 5.4 ± 2.7% for Monnal T60 and 8.8 ± 4.8% for Elisee 350. Grouping all conditions (P0.1 of 4 cmH2O and 8 cmH2O), trigger delay was 50 ± 11 ms, 71 ± 8 ms, 132 ± 22 ms, 60 ± 12 and 67 ± 6 ms for Engström Carestation, Osiris 3, Oxylog 3000, Monnal T60 and Elisee 350, respectively. Conclusions In surge situations such as COVID-19 pandemic, transport ventilators may be used to accurately control delivered volumes in locations, where only oxygen pressure supply is available. Performances regarding triggering function are acceptable for three out of the four transport ventilators tested.

Spring Meeting of the European-Materials-Research-Society (E-MRS) / Symposium M on Silicon Compatible Materials and Integrated Devices for Photonics and Optical Sensing.MAY 02-06, 2016.Lille, FRANCE.Location: Lille, FRANCEDate: MAY 02-06, 2016Sponsor(s):European Mat Res Soc; International audience; Micro-displays based on an array of micro-sized light emitting diodes (mu LEDs) are a promising technology for a wide range of applications. In these 2-dimensional arrays, each mu LED works as a single pixel of a whole image. In this paper we investigate the effect of size reduction on light emission and efficiency on InGaN/GaN LED devices ranging from 10*10 to 500*500 mu m(2). Electroluminescence characterizations together with current-voltage-luminance (IVL) measurements are conducted to study the homogeneity of light emission and correlate with efficiency measurements. The results show a strong size-dependent efficiency. Smaller LEDs exhibit lower maximum efficiency. The light emission homogeneity is shown to be dependent on current densities. At low current density, light emission is homogeneous across the surface of the LED, while inhomogeneity appears at higher current levels. We believe that fabrication process is partly responsible of this phenomenon through a degradation of the electrical injection. Our results are of high importance to understand the properties of mu lLED arrays. Indeed, such devices would allow the fabrication of very-high brightness emissive micro-displays.

A new approach for fabricating very-small pixel pitch GaN microdisplays is proposed. MicroLEDS obtained from silicon grown epi GaN layers exhibit performances comparable to those obtained on classical sapphire templates. This technology shows very great promises in the fabrication of high brightness, ultra-high-resolution microdisplays required for augmented reality systems.

Microdisplays based on an array of micro-sized GaN-based light emitting diodes (μLEDs) are very promising for high brightness applications. In this paper we investigate electro-optical properties of μLEDs arrays. A particular focus is made on size-reduction and light emission inhomogeneities. This work led us to process improvements, increasing maximum efficiency by 40%, reducing droop effect and enhancing brightness up to 107 cd/m².

We review the main challenges for fabricating high performance microLED displays for direct view applications from watch to large area TV. The main one is the transfer process of the microLEDs on the large area TFT backplane. We show how the microtube technology developed at LETI can ensure in one step both the mechanical and electrical connection between the two parts. Driving electronics is also a strong challenge. We also report a new approach providing full CMOS driving of the MicroLED display and a more efficient transfer solution. This new approach is paving the way for high-performance MicroLED displays, and in a much wider range of applications.

High-brightness GaN-based emissive microdisplays can be fabricated with different approaches that are listed and described. They consist either of hybridizing a GaN LED array on a CMOS circuit or building a monolithic component on a single substrate. Using the hybridization approach, two types of 10-μm pixel pitch GaN microdisplay prototypes were developed: (1) directly driven, 300 × 252 pixels and (2) active-matrix, 873 × 500 pixels. Brightness as high as 1 × 106 and 1 × 107 cd/m2 for blue and green arrays, respectively, were reached. GaN-based emissive microdisplays are suitable for augmented reality systems or head-up displays, but some challenges remain before they can be put in production.

Objectif : Au CHU d'Angers, hopital pavillonnaire, les transports intrahospitaliers medicalises, dits « tertiaires », reposent sur le Smur du SAMU 49. Cette organisation semble provoquer des evenements indesirables organisationnels (EIO) car le medecin de l'equipe ne peut assurer ni une autre intervention urgente, ni un renfort en regulation. L'objectif de cette etude est donc d'objectiver le retentissement reel d'une telle organisation.Materiel et methodes : Nous avons realise une etude observationnelle prospective de 120 jours ou etaient releves les EIO et les periodes sans renfort en regulation possible. Les EIO etaient definis par les carences, les retards d'engagement et les desengagements d'interventions Smur. Le critere de jugement principal etait la comparaison de frequence de survenue des EIO entre les periodes avec ou sans tertiaire en cours. Le critere de jugement secondaire etait la comparaison de frequence d'impossibilite de renfort en regulation entre les periodes avec ou sans tertiaire en cours.Resultats : Nous avons releve 156 EIO. La survenue d'EIO etait significativement plus elevee en periode avec tertiaire en cours (5,3 %) comparativement a celle sans tertiaire (1 %) (p : La realisation des transports tertiaires par le Smur du Samu 49 impacte directement son organisation et son activite. Au decours de cette evaluation, des mesures correctives ont ete mises en place dont l'efficacite devra etre evaluee.

High-brightness GaN-based emissive microdisplays can be fabricated with different approaches. Using the hybridization approach, we have developed 2 types of GaN microdisplay prototypes with a pixel pitch of 10 μm: passive-matrix, 300 x 252 pixels and active-matrix, 873 x 500 pixels. Brightness as high as 1 x 106 and 1 x 107 Cd/m2 for blue and green arrays, respectively were reached. This technology is suitable for augmented reality systems or Head-Up Displays

BACKGROUND: Recommendations regarding ventilation during cardiopulmonary resuscitation (CPR) are based on a low level of scientific evidence. We hypothesized that practices about ventilation during CPR might be heterogeneous and may differ worldwide. To address this question, we surveyed physicians from several countries on their practices during CPR. METHODS: We used a Web-based opinion survey. Links to the survey were sent by e-mail newsletters and displayed on the Web sites of medical societies involved in CPR practice from December 2013 to March 2014. RESULTS: 1,328 surveys were opened, and 548 were completed (41%). Responses came from 54 countries, but 64% came from 6 countries. Responders were mostly physicians (89%). From this group, 97% declared following specific CPR guidelines. Regarding practices, 28% declared always or frequently adopting only continuous chest compressions without additional ventilation. With regard to mechanical chest compression devices, 38% responded that such devices were available to them; when used, 28% declared always or frequently experiencing problems with ventilation such as frequent alarms. During bag-mask ventilation in intubated patients, 18% declared stopping chest compression during insufflation, and 39% applied > 10 breaths/min, which conflicts with international CPR guidelines. When a ventilator was used, the volume controlled mode was the most common strategy cited, but there was heterogeneity regarding ventilator settings for PEEP, trigger, FIO2, and breathing frequency. SpO2 and end-tidal CO2 were the 2 most monitored variables cited. CONCLUSIONS: Physicians indicated heterogeneous practices that often differ significantly from international CPR guidelines. This may reflect the low level of evidence and a lack of detailed recommendations concerning ventilation during CPR.

Patient: Female, 14 Final Diagnosis: Myopericarditis Symptoms: Cardiac tamponade • dyspnea • pericardial effusion • tachycardia Medication: — Clinical Procedure: Cardiopulmonary resuscitation Specialty: Infectious Diseases Objective: Unusual clinical course Background: Influenza viruses induce uncomplicated infections in most cases in individuals with no known predisposing factors. Acute febrile illness is generally limited to upper respiratory symptoms and several constitutional symptoms, including headache, lethargy, and myalgia. However, influenza A virus is a cause of severe morbidity and mortality worldwide. Some patients are at risk for serious and fatal complications. Cardiac involvement is a well-known condition, but, clinically apparent influenza myocarditis is not common. Few reports exist regarding recurrent fulminant influenza myocarditis. Case Report: We report here a fatal case of heart failure following myocarditis in a 14-year-old female who had seasonal flu symptoms but was otherwise healthy. H3N2 influenza virus infection was detected by molecular analyses of throat and nasal swabs, suggesting damage to myocardial cells caused directly by the virus. Conclusions: Pericardial effusion myopericarditis may occur during influenza virus infection in young individuals, even those with no known predisposing factors. Physicians need to be aware that acute myopericarditis can be a fatal complication of recent influenza virus infection in all patients with instable hemodynamics. Early diagnosis and treatment could reduce, in some cases, the risk of severe cardiac events. However, this sudden and fatal outcome was difficult to predict in a healthy young female with no known risk factors.

The electrical characteristics of bottom-gate amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) are reported. The a-IGZO TFTs without (w/o) a passivation layer have shown unstable electrical properties in air, such as negative shift of threshold voltage. This degradation is probably due to the IGZO environmental instability, especially in rich-oxygen and/or hydrogen environments. In this paper, the electrical behavior of TFTs passivated by various materials are presented. It has been observed that the passivation condition strongly affects device performance. The effect of passivation process, such as plasma-enhanced chemical vapor deposition (PECVD) and atomic layer deposition (ALD) on TFTs characteristics is investigated. In both passivation cases, a negative shift of threshold voltage has been observed by increasing the silane $(\hbox{SiH}_{4})$ flow rate in the first case, or by increasing the $\hbox{Al}_{2}\hbox{O}_{3}$ thickness in the later. By analyzing these TFTs with time of flight secondary ion mass spectroscopy (ToF-SIMS), hydrogen was detected. It appears that there is a significant correlation between hydrogen and TFT electrical degradation. The mechanisms leading to this degradation and the solutions to eliminate it are proposed.

Pocket ultrasound devices (PUDs) increase the scope of transthoracic echocardiography. We assessed the ability of emergency physicians (EPs) to obtain and interpret views using PUDs in prehospital emergencies.Nine EPs underwent a 2-day training program focused on acquisition of four views and on evaluation of left ventricular function, right ventricular size, the inferior vena cava, and detection of pericardial effusion. Then, EPs used a PUD to perform transthoracic echocardiography in patients with shock or acute respiratory failure. The quality and interpretation of views were graded by an expert as not obtained/inadequate, adequate, or optimal. Agreement between the expert and the physicians was evaluated using Cohen's κ test.One hundred consecutive exams were evaluated in patients with shock or acute respiratory failure. Parasternal long-axis and short-axis views, and a subcostal view were not obtained or inadequate in 56, 54, and 54 patients, respectively. An apical four-chamber view was not obtained or inadequate in 33 patients. One, two, or three views were graded as adequate or optimal in 86, 65, and 35 patients. Agreement between physicians and experts for left ventricular systolic function, right ventricular size, and pericardial effusion was weak [κ 0.37 (0.17; 0.59), 0.27 (0.023; 0.53), and 0.33 (-0.008; 0.67)]. Agreement for inferior vena cava evaluation was very weak [0.13 (-0.17; 0.43)].After a very short training program, echocardiography using a PUD in prehospital emergencies was feasible in half of patients. Acquisition of technical skills is reasonable, but accurate evaluation of cardiac function may require more extensive training.

Nanoelectronics will have to face major challenges in the next decades in order to proceed with increasing progress to the sub 10 nm nodes level and face the challenge to approach zero variability. The main requirements will be to reduce leakage currents and reduce access resistances at the same time in order to fully exploit 3D integration at the device, elementary function, chip and system. New progress laws combined to the scaling down of CMOS based technology will emerge to enable new paths to Functional Diversification. New materials and disruptive architectures, mixing logic and memories, Heterogeneous Integration, introducing 3D schemes at the Front End and Back End levels, will come into play to make it possible

We report the fabrication process and characterization of high resolution 873 x 500 pixels emissive arrays based on blue or green GaN/InGaN light emitting diodes (LEDs) at a reduced pixel pitch of 10 μm. A self-aligned process along with a combination of damascene metallization steps is presented as the key to create a common cathode which is expected to provide good thermal dissipation and prevent voltage drops between center and side of the micro LED matrix. We will discuss the challenges of a self-aligned technology related to the choice of a good P contact metal and will present our solutions for the realization of the metallic interconnections between the GaN contacts and the higher levels of metallization at such a small pixel pitch. Enhanced control of each technological step allows scalability of the process up to 4 inch LED wafers and production of high quality LED arrays. The very high brightness (up to 10 7 cd.m -2 ) and good external quantum efficiency (EQE) of the resulting device make these kind of micro displays suitable for augmented reality or head up display applications.

LED have become the main light sources of the future as they open the path for intelligent use of light in time, intensity and color. In many usages, strong energy economy is done by adjusting these properties. The smart lighting has three dimensions, energy efficiency brought by GaN blue emitting LEDs, integration of electronics, sensors, microprocessors in the lighting system and development of new functionalities and services provided by the light. Monolithic LED arrays allow two major innovations, the spatial control of light emission and the adjustment of the electrical properties of the source.

We have demonstrated the color conversion of blue micro-LEDs by means of QDs. In this paper, we will present characterizations that highlight this phenomenon. We already obtained conversion with a complete disappearance of the blue incident signal and a strong color saturation from deep blue (x=0,1626; y=0,0144) to deep red (x=0,6743; y=0,3244).

The semiconductor industry has a highly developed infrastructure for silicon processing with a high level of automation, state of the art facilities and the ability to deal with large volumes which lead to lower fabrication costs. GaN on silicon can take advantage of this maturity of process, especially with the use of 200mm substrates giving access to large CMOS compatible fabs. This requires specific growth tools, such as that shown in figure 1, and a typical GaN on silicon wafer is shown in figure 2. Combining the industrialization techniques of silicon with the outstanding properties of a wideband gap material such as GaN can result in high performance devices and new functionality for a wide variety of applications in power conversion, radio-frequency electronics and opto-electronics. Power electronics is currently a very active topic, with multiple academic and industrial players working on GaN based materials, in particular due to the availability of HEMT structures as shown in figure 3 that can be integrated on silicon substrates. Such structures have high carrier mobility and the capability to withstand high critical electrical fields, which makes them extremely promising for power conversion applications at lower cost compared to bulk silicon carbide devices for example. Moreover, with aggressive device scaling compared to silicon power transistors, such devices allow higher frequency operation which in combination with high temperature operation, ensure more compact and greener energy converters at more competitive prices. Beyond traditional power conversion, radio frequency applications are also a field where GaN is of great interest. Although the market is today mainly covered by GaN on silicon carbide layers to address high performance demands such as military radar, high volume markets are now pushing for products at more competitive prices. In particular GaN on silicon is a candidate of increasing interest for the next generation of 5G networks in development. Finally, GaN on silicon has been proposed for many years as a solution to reduce LED fabrication costs. However the move into production has not occurred on a large scale, in particular due to the ever decreasing costs of GaN on sapphire devices and the difficulties of growing the very high quality GaN required for LEDs on silicon substrates. However, new applications such as micro-displays, with pixels shown in figure 4, are once again making GaN on silicon attractive for LEDs production, as large wafers and low defectivity of CMOS compatible processing mean that pixel yield and therefore device yield can be maintained, which is much harder to achieve for traditional GaN on sapphire production. This talk will describe the basics of growth of GaN on silicon, and the techniques of strain engineering required to produce flat wafers at room temperature. We will also look at the different in-situ characterizations available and discuss the different information that we can extract from these to ensure easier development of layers and better control of production. We will then examine the specific challenges of GaN on silicon growth, and the difficulties associated with the integration of these layers into CMOS compatible fabs. In particular, we will look at the different forms of defectivity found during GaN on silicon growth, with an example shown in figure 5. These defects must be avoided, to ensure high performance and high yield, to ensure CMOS compatibility and also to avoid an impact on the fragility of wafers, which is a serious issue for GaN on silicon wafers. We will also present some of the current solutions being implemented by LETI in order to counteract these difficulties and move towards truly CMOS compatible layers. An example of a fully processed wafer is shown in figure 6. Finally we will examine the specific challenges for GaN on silicon for each of the above applications, in terms of layer performance and integration difficulties, before looking ahead to future concepts for GaN on silicon layers, and further integration of these layers including hybrid LED micro-displays, and integrated circuits for power electronics. Figure 1

Bottom gate microcrystalline silicon thin film transistors (μc-Si:H TFT) have been fabricated at three different deposition temperatures (150, 200 and 250 °C) for the μc-Si layer. We found that the linear field effect mobility increases from 0.1 to 0.44 cm 2 /V s by decreasing the temperature from 250 °C to 150 °C, and that the leakage current of TFTs with μc-Si deposited at 150 °C is lower than that of μc-Si:H deposited at 250 °C. Moreover, there is no influence of the deposition temperature on the stability of μc-Si:H TFTs. The improvement of the electrical characteristics at lower deposition temperatures is discussed in terms of a lower concentration of donor active oxygen atoms at lower temperature.

Bottom gate microcrystalline silicon thin film transistors (μc-Si TFT) have been realized with two types of films: μc-Si(1) and μc-Si(2) with crystalline fraction of 80% and close to 100% respectively. On these TFTs we applied two types of passivation (SiN x and resist). μc-Si TFTs with resist as a passivation layer present a low leakage current of about 2.10 − 12 A for V G = − 10 and V D = 0.1V an ON to OFF current ratio of 10 6 , a threshold voltage of 7 V, a linear mobility of 0.1 cm 2 /V s, and a sub-threshold voltage of 0.9 V/dec. Microcrystalline silicon TFTs with SiN x as a passivation present a new phenomenon: a parasitic current for negative gate voltage (− 15 V) causes a bump and changes the shape of the sub-threshold region. This excess current can be explained by and oxygen contamination at the back interface.

We have developed Low Temperature Poly-Silicon (LTPS) backplanes on metal for flexible 2.8-in. Active-Matrix Organic Light Emission Diode (AM-OLED) displays. The PMOS devices exhibit interesting characteristics such as field-effect mobility of 83 cm2/V.s, on/off current ratio of more than 107, a substhreshold slope of 0.47 V/dec, and a leakage current of 0.02 pA/μm at Vds = 0.1 V. Also, thin film transistors (TFT) characteristics were shown to be very homogeneous across the plates. These good performances are attributed to the possibility of developing an LTPS process on metal very close to the process existing on glass, thanks to the use of plasma enhanced chemical vapour deposition (PECVD) SiO2 as the thick insulator, which provides to maintain high temperature budget. The influence of the metal substrate as a back-gate was studied as a function of the insulator thickness. Based on simulation and measurements, it was evidenced that the metal potential can have a significant influence on the TFT operation. Overall, this self-aligned LTPS process on metal seems to be very promising for the manufacturing of high quality and high resolution flexible AM-OLED displays.

Bottom-gated n-channel thin-film transistors (TFTs) were fabricated on amorphous silicon (a-Si)/nanocrystalline silicon (nc-Si) bilayers, deposited at 230 °C by plasma-enhanced chemical vapour deposition. The impact of the channel length on the electrical and low-frequency noise characteristics of the TFTs is investigated. The results show that the 1/ f noise can be interpreted in terms of carrier number fluctuations, except the long channel devices where the 1/ f noise is interpreted in terms of the Hooge’s mobility fluctuations model at low drain currents. The gate insulator trap density has been evaluated, demonstrating that the nc-Si extended underneath the n + drain contact area contributes to the measured noise.

The effect of the channel width dimension on the electrical characteristics of amorphous/nanocrystalline silicon bilayer thin-film transistors (TFTs) is investigated. For comparison, nanocrystalline silicon monolayer TFTs are also studied. The experimental results show that the leakage current is decreased and the back-channel conduction is suppressed in bilayer channel devices. The overall results demonstrate that the performance of bilayer TFTs is enhanced with decreasing the channel width, which is attributed to the corner effect

The aim of this study was to compare the outcomes of kidney transplants from uncontrolled DCD (uDCD) with kidney transplants from extended (ECD) and standard criteria donors (SCD). In this multicenter study, we included recipients from uDCD (n = 50), and from ECD (n = 57) and SCD (n = 102) who could be eligible for a uDCD program. We compared patient and graft survival, and kidney function between groups. To address the impact of preservation procedures in uDCD, we compared in situ cold perfusion (ICP) with normothermic regional perfusion (NRP). Patient and graft survival rates were similar between the uDCD and ECD groups, but were lower than the SCD group (P < 0.01). Although delayed graft function (DGF) was more frequent in the uDCD group (66%) than in the ECD (40%) and SCD (27%) groups (P = 0.08 and P < 0.001), graft function was comparable between the uDCD and ECD groups at 3 months onwards post-transplantation. The use of NRP in the uDCD group (n = 19) was associated with a lower risk of DGF, and with a better graft function at 2 years post-transplantation, compared to ICP-uDCD (n = 31) and ECD. In conclusion, the use of uDCD kidneys was associated with post-transplantation results comparable to those of ECD kidneys. NRP preservation may improve the results of uDCD transplantation.