4H-SiC surface morphology after Al ion implantation and annealing with C-cap.

The root mean square (rms) surface roughness extracted from atomic force microscopy is widely employed to complement the characterisation of ion implantation processes in 4H-SiC. It is known that the protection of a carbon film eliminates or mitigates roughening of the SiC surface during postimplantation annealing. This study, based on a rich original data collection of Al+ ion implanted 4H-SiC samples, allows for a quantitative description of the surface morphology as a function of the annealing temperature and time and of the Al implanted concentration. With increasing thermal budget, the evolution from flat, to blurred with ripples, granular, and finally jagged surface, results in a monotonous increase in the root mean square roughness. Additional information is given by the trends of the roughness exponent and of the correlation length, extracted from the height-height correlation function, which account for the surface evolution below 1700°C and for the effect of the Al implanted concentration on the ripple size, respectively. A combination of low roughness parameter and high correlation length identify the transition from ripples to jagged morphology. LAY DESCRIPTION: Selective area doping is a key step in the fabrication of hexagonal Silicon Carbide (4H-SiC) power electronic devices. It is achieved by ion implantation followed by a high temperature postimplantation annealing to restore the lattice and electrically activate the dopants. Aluminium, the preferred p-type dopant, is electrically activated at temperature ranging between 1500°C and 2000°C. The time required to complete the activation process is longer the lower the annealing temperature, spanning between some minutes and hundreds of hours. During annealing, 4H-SiC wafers are encapsulated by a temperature-resistant carbon layer (C-cap) in order to avoid step bunching and reduce surface roughening. Nevertheless, surface modifications can occur at high temperature. For this reason, the characterisations of 4H-SiC doping processes report not only the electrical activation of the dopants, but also the root mean square surface roughness obtained at the end of the process. However, rms values can be scattered because technological parameters such as the heating system and the way to deposit and remove the C-cap can affect the final result as well as the process parameters. Furthermore, the C-cap resistance to long annealing has been proven only by electrical measurements, but the surface morphology has never been observed. This work presents a quantitative characterisation of the surface morphology of Al implanted 4H-SiC as a function of the annealing temperature, time and of the Al implanted concentration, independent of the heating system and of the C-cap technology. The produced sample collection allowed to correlate characteristic surface features with the corresponding quantities extracted from image analysis that can be more sensitive to process parameters than the sole rms. These findings can be used to enrich process optimisation tools.

Hood colonoscopy in trainees: a useful adjunct to improve the performance.

BACKGROUND: The use of a transparent hood to improve colonoscopic performance has recently been proposed. AIMS: The purpose of this study was to evaluate whether using the hood might improve the cecal intubation rate, cecal intubation time, number of attempts needed to intubate the ileo-cecal valve, and polyp detection rate in trainees. METHODS: Patients undergoing colonoscopy (n = 378) were randomized in two groups, one studied with hood colonoscopy (n = 179) and the other (n = 199) with standard examination. RESULTS: No differences were found between hood and standard colonoscopy with respect to cecal intubation rate (95 vs 92 %), whereas hood colonoscopy significantly shortened the cecal intubation time, the number of attempts needed to intubate the ileo-cecal valve, and the overall polyp detection rate (p < 0.01 for all these variables). CONCLUSIONS: Hood colonoscopy might represent a useful adjunct to standard colonoscopy, especially improving the performance of endoscopic trainees.

Development of a Membrane Module Prototype for Oxygen Separation in Industrial Applications.

The integration of oxygen transport membranes in industrial processes can lead to energy and economic advantages, but proof of concept membrane modules are highly necessary to demonstrate the feasibility of this technology. In this work, we describe the development of a lab-scale module through a comprehensive study that takes into consideration all the relevant technological aspects to achieve a prototype ready to be operated in industrial environment. We employed scalable techniques to manufacture planar La0.6Sr0.4Co0.2Fe0.8O3-δ membrane components suitable for the application in both 3- and 4-end mode, designed with a geometry that guarantees a failure probability under real operating conditions as low as 2.2 × 10-6. The asymmetric membranes that act as separation layers showed a permeation of approx. 3 NmL/min/cm2 at 900 °C in air/He gradient, with a remarkable stability up to 720 h, and we used permeation results to develop a CFD model that describes the influence of the working conditions on the module performance. The housing of the membrane component is an Inconel 625 case joined to the membrane component by means of a custom-developed glass-ceramic sealant that exhibited a remarkable thermo-chemical compatibility both with metal and ceramic, despite the appearance of chemical strain in LSCF at high temperature. The multi-disciplinary approach followed in this work is suitable to be adapted to other module concepts based on membrane components with different dimensions, layouts or materials.

Sustainability in gastroenterology and digestive endoscopy: Position Paper from the Italian Association of Hospital Gastroenterologists and Digestive Endoscopists (AIGO).

Climate crisis is dramatically changing life on earth. Environmental sustainability and waste management are rapidly gaining centrality in quality improvement strategies of healthcare, especially in procedure-dominant fields such as gastroenterology and digestive endoscopy. Therefore, healthcare interventions and endoscopic procedures must be evaluated through the 'triple bottom line' of financial, social, and environmental impact. The purpose of the paper is to provide information on the carbon footprint of gastroenterology and digestive endoscopy and outline a set of measures that the sector can take to reduce the emission of greenhouse gases while improving patient outcomes. Scientific societies, hospital executives, single endoscopic units can structure health policies and investment to build a "green endoscopy". The AIGO study group reinforces the role of gastrointestinal endoscopy professionals as advocates of sustainability in digestive endoscopy. The "green endoscopy" can shape a more sustainable health service and lead to an equitable, climate-smart, and healthier future.

Spectral endoscopic imaging: the multiband system for enhancing the endoscopic surface visualization.

In the past few years, newly developed procedures and technologies have improved endoscopic recognition of the gastrointestinal tract. In particular, narrow band imaging, multiband imaging, and contrast enhancement make possible the "real-time," on demand recognition of the gastrointestinal mucosa during the endoscopic examination. These imaging techniques have been designed to enhance visualization of the vascular network and surface texture of the mucosa in an effort to improve tissue characterization, differentiation, and diagnosis. These techniques are considered as potential alternatives to chromoendoscopy because they provide contrast enhancement of tissue surface structures. This review focuses on data published on multiband imaging system. We report the technological basis of the system and speculate on its applications. Therefore, PubMed was searched for articles published up to 31 October 2009 using, in combination, these terms: "multiband imaging," "band imaging," "endoscopy," "high-resolution," "gastrointestinal," "FICE," "magnification," "spectral endoscopic images," "computed virtual chromoendoscopy." The reference list of articles identified in the initial PubMed search was reviewed for further relevant publications. Abstracts of communications presented to the most relevant international meetings and congresses were also included in this review. We did not carry out meta-analyses and reviewed only articles published in English.

Correct use of telemedicine in gastroenterology, hepatology, and endoscopy during and after the COVID-19 pandemic: Recommendations from the Italian association of hospital gastroenterologists and endoscopists (AIGO).

The purpose of the present document is to provide detailed information on the correct and optimal use of digital media to ensure continuity of care for gastroenterological patients in everyday clinical practice, in health emergencies and/or when the patient cannot reach the hospital for other reasons. During the recent COVID-19 pandemic, telemedicine has allowed many patients with chronic diseases to access remote care worldwide, proving to be the ideal solution to overcome restrictions and carry out non-urgent routine follow-ups on chronic patients. The COVID-19 pandemic has therefore made organizational and cultural renewal essential for the reorganization of healthcare in order to ensure greater continuity of care with a minimum risk of spreading the virus to users, practitioners and their families. These AIGO recommendations are intended to provide Italian gastroenterologists with a tool to use this method appropriately, in compliance with current legislation, in particular the proper approach and procedures for conducting a remote examination using a video conferencing tool, the so-called televisit. In the near future, telemedicine may contribute to a possible reorganization of healthcare systems, through innovative care models focusing on the citizen and facilitating access to services throughout the entire Country.

Asymmetric LSCF Membranes Utilizing Commercial Powders.

Powders of constant morphology and quality are indispensable for reproducible ceramic manufacturing. In this study, commercially available powders were characterized regarding their microstructural properties and screened for a reproducible membrane manufacturing process, which was done by sequential tape casting. Basing on this, the slurry composition and ratio of ingredients were systematically varied in order to obtain flat, crack-free green tapes suitable for upscaling of the manufacturing process. Debinding and sintering parameters were adjusted to obtain defect-free membranes with diminished bending. The crucial parameters are the heating ramp, sintering temperature, and dwell time. The microstructure of the asymmetric membranes was investigated, leading to a support porosity of approximately 35% and a membrane layer thickness of around 20 µm. Microstructure and oxygen flux are comparable to asymmetric La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) membranes manufactured from custom-made powder, showing an oxygen flux of > 1 mLcm-2min at 900 °C in air/Ar gradient.

The water immersion technique is easy to learn for routine use during EGD for duodenal villous evaluation: a single-center 2-year experience.

GOALS: We investigated the learning parameters of the immersion technique for the assessment of marked villous atrophy (MVA), during routine esophagogastroduodenoscopy (EGD). BACKGROUND: The immersion technique offers a proven possibility of enhancing the sensitivity of endoscopy in detecting duodenal villous atrophy patterns. STUDY: Nine endoscopists with at least 2 years of experience, who had previously been trained to perform the immersion technique, searched for duodenal villi during routine EGD. In a 2-year study, duodenal villi were evaluated underwater duodenoscopy in 432 patients from whom duodenal biopsies had been, for various reasons, obtained. The endoscopic findings were compared with the histology. The learning parameters of the water immersion technique and the accuracy in detecting subjects with MVA were observed. RESULTS: A total of 28 (6.5%) patients with MVA were identified during endoscopy by the trained endoscopists. All these patients were diagnosed as being celiac patients. The sensitivity, specificity, and accuracy (positive and negative predictive values) of the immersion technique in detecting MVA patterns, irrespective of the endoscopist who performed the examination, were always 100%. CONCLUSIONS: The underwater evaluation of the duodenum can be efficiently and regularly performed during routine EGD by endoscopists with 2 years of experience, after a specific, brief training period. This procedure is simple, feasible, and can accurately detect MVA patterns.

Optimal band imaging system: a new tool for enhancing the duodenal villous pattern in celiac disease.

BACKGROUND: The optimal band imaging (OBI) system is a new technology that can select better spectral images decomposed from ordinary endoscopic images. This technology, first introduced as "FUJI Intelligent Color Enhancement," enhances the contrast of the mucosal surface without the use of dyes. OBJECTIVE: This study aimed to evaluate the potential of OBI for predicting the duodenal villous morphologic characteristics in patients with suspected celiac disease. DESIGN: This study was designed as an open, prospective, single-center trial. Duodenoscopy was performed with a high-resolution magnification view, in association with OBI spectral processing. Duodenal villous patterns were evaluated and classified as normal, partially atrophic, or markedly atrophic. The endoscopic results were then compared with the histologic diagnosis. SETTING: Endoscopy unit at the A. Gemelli University Hospital of Rome, Italy. PATIENTS: Sixty-one patients undergoing upper endoscopy for clinical history of malabsorption or serologic suspicion for celiac disease were included in the study. RESULTS: From OBI sets using red, green, and blue wavelength combinations that ranged from 400 to 580 nm, the endoscopist was able to find marked villous atrophy of the duodenum in 16 subjects, partial villous atrophy in 9 subjects, and normal villi in the remaining 36 subjects. The sensitivity, specificity, and positive and negative predictive values of the OBI-based duodenoscopy were 100% accurate in the evaluation of villous patterns. CONCLUSIONS: High-resolution magnification endoscopy with OBI allows clear visualization of the duodenal villous pattern. The OBI system may play a potential role in optimizing the diagnostic accuracy of endoscopy in celiac disease.

S-induced modifications of the optoelectronic properties of ZnO mesoporous nanobelts.

The synthesis of ZnO porous nanobelts with high surface-to-volume ratio is envisaged to enhance the zinc oxide sensing and photocatalytic properties. Yet, controlled stoichiometry, doping and compensation of as-grown n-type behavior remain open problems for this compound. Here, we demonstrate the effect of residual sulfur atoms on the optical properties of ZnO highly porous, albeit purely wurtzite, nanobelts synthesized by solvothermal decomposition of ZnS hybrids. By means of combined cathodoluminescence analyses and density functional theory calculations, we attribute a feature appearing at 2.36 eV in the optical emission spectra to sulfur related intra-gap states. A comparison of different sulfur configurations in the ZnO matrix demonstrates the complex compensating effect on the electronic properties of the system induced by S-inclusion.

Regression of EI2-stage low-grade gastric MALT-lymphoma after H. pylori eradication.

To our knowledge there are only a few reports showing a role of eradication therapy for H. pylori in the treatment of low-grade MALT-lymphoma, of stage EI2. We report a rare case of MALT-lymphoma, invading all of the gastric wall, which regressed after eradication of H. pylori. The regression was well documented by endoscopic ultrasonography (EUS). A 70-year-old man was referred to us for upper endoscopy that showed a single ulcer of 3cm in diameter at the gastric angulus. Histology, immunohistochemistry and PCR analyses diagnosed a low-grade MALT-lymphoma in the presence of H. pylori infection. EUS showed a tumor invasion of all the gastric wall. The serosa layer, also, appeared irregular and interrupted in some points. The lymph nodes around the duodenum and the stomach were not involved. An anti-H. pylori therapy was started. After 1 year from the diagnosis, EUS showed the reappearance of the normal layers of the stomach. The patient is actually disease free. This result suggests that in EI2-stage gastric lymphoma of MALT type, in the absence of both high-grade malignancy foci and t(11;18)(q21;q21) chromosomal translocation, an eradication treatment may be considered as a first therapeutic option.

Long-term efficacy of the surgical treatment of buffalo hump in patients continuing antiretroviral therapy.

Fat redistribution disorders are common complications of antiretroviral therapy. Corrective surgery is increasingly used to treat localized fat accumulations that are difficult to treat medically or by changes in drug regimens, but is limited by relapses caused by the continuation of antiretroviral therapy. The surgical treatment of buffalo hump has a long-term favourable effect in the majority of patients continuing antiretroviral therapy, and can therefore be considered in patients experiencing considerable physical or psychological discomfort.

Increased mitochondrial DNA content in peripheral blood lymphocytes from HIV-infected patients with lipodystrophy.

We have evaluated mitochondrial (mt) DNA content in CD4 and CD8 peripheral blood lymphocytes (PBLs) from HIV-infected patients taking highly active antiretroviral therapy (HAART) who display different types of adipose tissue alterations. A cross-sectional study was performed in a total of 23 patients with lipodystrophy (LD): nine patients with fat accumulation, six patients with fat loss, eight patients with combined form, who were compared to 11 individuals infected by HIV without LD (HIV-positive) and 10 seronegative controls (CTRL). PBLs were obtained by standard methods, that is, gradient density centrifugation on Ficoll, and CD4 or CD8 cells were positively isolated by magnetic sorting to eliminate the contamination of platelets. mtDNA content was then measured by an original assay based upon real-time PCR. mtDNA content was significantly increased in CD4 T cells from patients with LD, while no differences were present between CD4 and CD8 cells from HIV-positive and CTRL individuals. Nor were any differences found when comparing LD or HIV-positive patients treated with stavudine or zidovudine, or taking D-drugs or non D-drugs. Patients with fat accumulation had significantly higher mtDNA content compared to HIV-positive and CTRL, this phenomenon regarding both CD4 and CD8 PBLs. Considering all HIV-positive patients (including LD), mtDNA content showed a significant, positive correlation with cholesterolaemia but not with triglyceridaemia and glycaemia. Relatively high mtDNA content in LD patients, as well as the correlation between mtDNA content and cholesterol in all HIV-positive subjects, suggest the involvement of mitochondria in such a pathology. However, further studies are needed to confirm these initial observations and ascertain whether the quantification of mtDNA in PBL is a useful and reliable marker to investigate and monitor HAART-related changes in fat distribution.

Mesoporous single-crystal ZnO nanobelts: supported preparation and patterning.

We demonstrate that highly porous ZnO nanobelts can be prepared by thermally decomposing ZnS(en)(0.5) hybrid nanobelts (NBs) synthesized through a solvothermal route using Zn layers deposited on alumina substrates as both the Zn substrate and source. Hybrid decomposition by thermal annealing at 400 °C gives porous ZnS NBs that are transformed by further annealing at 600 °C into wurtzite single crystal ZnO nanobelts with an axial direction of [0001]. The evolution of the morphological and structural transformation ZnS(en)(0.5)→ ZnS → ZnO is investigated at the nanoscale by transmission and scanning electron microscopy analyses. Control of the ZnO NB distributions by patterning the Zn metallization on alumina is achieved as a consequence of the parent hybrid NB patterned growth. The presence of NBs on alumina in a ∼100 µm wide region between Zn stripes allows us to fabricate two contact devices where contact pads are electrically connected through a porous ZnO NB entanglement. Such devices are suitable for employment in photodetectors as well as in gas and humidity sensors.

Self-expandable metal stenting of refractory upper gut corrosive strictures: a new role for endoscopy?

Caustic strictures of the gastrointestinal tract are often difficult to treat, since relapses are frequent after medical or endoscopic treatment. Thus, novel approaches are needed. We report here our experience with self-expandable metallic stents (SEMS) as a new endoscopic approach in three patients with corrosive strictures of the upper gastrointestinal tract.

Emerging technologies in upper gastrointestinal endoscopy and celiac disease.

Despite advances in our knowledge of celiac disease, the most current and authoritative recommendations conclude that diagnosis requires at least four biopsy specimens to be taken from the duodenal area. These recommendations are based on the perception that classic endoscopic markers are not adequate to target biopsy sampling to sites of villous damage in the duodenum. In the past few years, newly developed procedures and technologies have improved endoscopic recognition of the duodenum. These advances make possible the real-time recognition of the duodenal villous pattern during an upper endoscopy procedure, and thereby have the potential to optimize diagnostic accuracy. It is, therefore, reasonable to hypothesize that upper endoscopy might have a more incisive role in the diagnosis of celiac disease than merely providing a means of obtaining biopsy specimens for histological analysis. This Review highlights the new technologies in the field of upper endoscopy that could be helpful for the diagnosis of celiac disease, including the water-immersion technique, chromoendoscopy, high-resolution magnification endoscopy, optimal band imaging, optical coherence tomography and confocal endomicroscopy.

Risk factors for HIV/AIDS in a low HIV prevalence site of sub-Saharan Africa.

We conducted a hospital-based survey on prevalence and risk factors of HIV-1/2 and other viral infections in Zanzibar archipelago. Blood samples, socio-demographic and behavioural data were collected from 2697 patients. The overall HIV prevalence was 2.9%. About 1.4%, 2.1%, 4.2% of antenatal clinic (ANC) attendees and 2.1%, 3.7%, 5.3% of blood donors were, respectively, HIV-Abs-, HTLV-Abs- and HBs-Ag-positive; 5.5% of blood donors were HCV-affected. Co-infections were rare. Exactly 3.4% of the children aged 6-10 years were HIV-positive. People aged 26-35 years [adjusted odds ratio (AOR) 4.4, 95% CI (confidence interval) 1.72-11.22; P = 0.002], illiterate subjects (AOR 3.6, 95% CI 1.65-7.98; P = 0.001) mobile workers (AOR 7.0, 95% CI 1.41-34.62; P = 0.02) and previously operated patients (AOR 1.9, 95% CI 1.02-3.66; P = 0.04) were at higher risk for HIV/AIDS. Any of the examined factors were associated with hepatitis B virus, hepatitis C virus and human T lymphotropic virus type 1/2 transmission. HIV/AIDS prevention strategies must primarily be addressed to traditional high-risk groups and secondarily to unsafe health care procedures in relatively preserved sub-Saharan areas.