Ophthalmology Optical Coherence Tomography Databases for Artificial Intelligence Algorithm: A Review.

BACKGROUND: Imaging plays a pivotal role in eye assessment. With the introduction of advanced machine learning and artificial intelligence (AI), the focus has shifted to imaging datasets in ophthalmology. While disparities and health inequalities hidden within data are well-documented, the ophthalmology field faces specific challenges to the creation and maintenance of datasets. Optical Coherence Tomography (OCT) is useful for the diagnosis and monitoring of retinal pathologies, making it valuable for AI applications. This review aims to identify and compare the landscape of publicly available optical coherence tomography databases for AI applications. METHODS: We conducted a literature review on OCT and AI articles with publicly accessible datasets, using PubMed, Scopus, and Web of Science databases. The review retrieved 183 articles, and after full-text analysis, 50 articles were included. From the included articles were identified 8 publicly available OCT datasets, focusing on patient demographics and clinical details for thorough assessment and comparison. RESULTS: The resulting datasets encompass 154,313 images collected from Spectralis, Cirrus HD, Topcon 3D, and Bioptigen devices. These datasets included normal exams, age-related macular degeneration, and diabetic maculopathy, among others. Comprehensive demographic information is available in one dataset and the USA is the most represented population. DISCUSSION: Current publicly available OCT databases for AI applications exhibit limitations, stemming from their non-representative nature and the lack of comprehensive demographic information. Limited datasets hamper research and equitable AI development. To promote equitable AI algorithmic development in ophthalmology, there is a need for the creation and dissemination of more representative datasets.

Artificial intelligence for telemedicine diabetic retinopathy screening: a review.

PURPOSE: This study aims to compare artificial intelligence (AI) systems applied in diabetic retinopathy (DR) teleophthalmology screening, currently deployed systems, fairness initiatives and the challenges for implementation. METHODS: The review included articles retrieved from PubMed/Medline/EMBASE literature search strategy regarding telemedicine, DR and AI. The screening criteria included human articles in English, Portuguese or Spanish and related to telemedicine and AI for DR screening. The author's affiliations and the study's population income group were classified according to the World Bank Country and Lending Groups. RESULTS: The literature search yielded a total of 132 articles, and nine were included after full-text assessment. The selected articles were published between 2004 and 2020 and were grouped as telemedicine systems, algorithms, economic analysis and image quality assessment. Four telemedicine systems that perform a quality assessment, image preprocessing and pathological screening were reviewed. A data and post-deployment bias assessment are not performed in any of the algorithms, and none of the studies evaluate the social impact implementations. There is a lack of representativeness in the reviewed articles, with most authors and target populations from high-income countries and no low-income country representation. CONCLUSIONS: Telemedicine and AI hold great promise for augmenting decision-making in medical care, expanding patient access and enhancing cost-effectiveness. Economic studies and social science analysis are crucial to support the implementation of AI in teleophthalmology screening programs. Promoting fairness and generalizability in automated systems combined with telemedicine screening programs is not straightforward. Improving data representativeness, reducing biases and promoting equity in deployment and post-deployment studies are all critical steps in model development.

Pharmacological treatment for Buerger's disease.

BACKGROUND: Buerger's disease (thromboangiitis obliterans) is a non-atherosclerotic, segmental inflammatory pathology that most commonly affects the small and medium sized arteries, veins, and nerves in the upper and lower extremities. The aetiology is unknown, but involves hereditary susceptibility, tobacco exposure, immune and coagulation responses. In many cases, there is no possibility of revascularisation to improve the condition. Pharmacological treatment is an option for patients with severe complications, such as ischaemic ulcers or rest pain.This is an update of the review first published in 2016. OBJECTIVES: To assess the effectiveness of any pharmacological agent (intravenous or oral) compared with placebo or any other pharmacological agent in patients with Buerger's disease. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, AMED, the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials register to 15 October 2019. The review authors searched LILACS, ISRCTN, Australian New Zealand Clinical Trials Registry, EU Clinical Trials Register, clincialtrials.gov and the OpenGrey Database to 5 January 2020. SELECTION CRITERIA: We included randomised controlled trials (RCTs) involving pharmacological agents used in the treatment of Buerger's disease. DATA COLLECTION AND ANALYSIS: Two review authors, independently assessed the studies, extracted data and performed data analysis. MAIN RESULTS: No new studies were identified for this update. Five randomised controlled trials (total 602 participants) compared prostacyclin analogue with placebo, aspirin, or a prostaglandin analogue, and folic acid with placebo. No studies assessed other pharmacological agents such as cilostazol, clopidogrel and pentoxifylline or compared oral versus intravenous prostanoid. Compared with aspirin, intravenous prostacyclin analogue iloprost improved ulcer healing (risk ratio (RR) 2.65; 95% confidence interval (CI) 1.15 to 6.11; 98 participants; 1 study; moderate-certainty evidence), and helped to eradicate rest pain after 28 days (RR 2.28; 95% CI 1.48 to 3.52; 133 participants; 1 study; moderate-certainty evidence), although amputation rates were similar six months after treatment (RR 0.32; 95% CI 0.09 to 1.15; 95 participants; 1 study; moderate-certainty evidence). When comparing prostacyclin (iloprost and clinprost) with prostaglandin (alprostadil) analogues, ulcer healing was similar (RR 1.13; 95% CI 0.76 to 1.69; 89 participants; 2 studies; I² = 0%; very low-certainty evidence), as was the eradication of rest pain after 28 days (RR 1.57; 95% CI 0.72 to 3.44; 38 participants; 1 study; low-certainty evidence), while amputation rates were not measured. Compared with placebo, the effects of oral prostacyclin analogue iloprost were similar for: healing ischaemic ulcers (iloprost 200 mcg: RR 1.11; 95% CI 0.54 to 2.29; 133 participants; 1 study; moderate-certainty evidence, and iloprost 400 mcg: RR 0.90; 95% CI 0.42 to 1.93; 135 participants; 1 study; moderate-certainty evidence), eradication of rest pain after eight weeks (iloprost 200 mcg: RR 1.14; 95% CI 0.79 to 1.63; 207 participants; 1 study; moderate-certainty evidence, and iloprost 400 mcg: RR 1.11; 95% CI 0.77 to 1.59; 201 participants; 1 study; moderate-certainty evidence), and amputation rates after six months (iloprost 200 mcg: RR 0.54; 95% CI 0.19 to 1.56; 209 participants; 1 study, and iloprost 400 mcg: RR 0.42; 95% CI 0.13 to 1.31; 213 participants; 1 study). When comparing folic acid with placebo in patients with Buerger's disease and hyperhomocysteinaemia, pain scores were similar, there were no new cases of amputation in either group, and ulcer healing was not assessed (very low-certainty evidence). Treatment side effects such as headaches, flushing or nausea were not associated with treatment interruptions or more serious consequences. Outcomes such as amputation-free survival, walking distance or pain-free walking distance, and ankle brachial index were not assessed by any study. Overall, the certainty of the evidence was very low to moderate, with few studies, small numbers of participants, variation in severity of disease of participants between studies and missing information (for example regarding baseline tobacco exposure). AUTHORS' CONCLUSIONS: Moderate-certainty evidence suggests that intravenous iloprost (prostacyclin analogue) is more effective than aspirin for eradicating rest pain and healing ischaemic ulcers in Buerger's disease, but oral iloprost is not more effective than placebo. Very low and low-certainty evidence suggests there is no clear difference between prostacyclin (iloprost and clinprost) and the prostaglandin analogue alprostadil for healing ulcers and relieving pain respectively in severe Buerger's disease. Very low-certainty evidence suggests there is no clear difference in pain scores and amputation rates between folic acid and placebo, in people with Buerger's disease and hyperhomocysteinaemia. Further well designed RCTs assessing the effectiveness of pharmacological agents (intravenous or oral) in people with Buerger's disease are needed.

Transverse versus vertical groin incision for femoral artery approach.

BACKGROUND: Access to the femoral vessels is necessary for a wide range of vascular procedures, including treatment of thromboembolic disease, arterial grafts (i.e. bifemoral aortic bypass or infrainguinal bypass), endovascular repair of abdominal aortic aneurysm (EVAR), thoracic endovascular aneurysm repair (TEVAR) and transcatheter aortic valve implantation (TAVI). The surgical technique used to access the femoral artery may be a factor in the occurrence of postoperative complications; this will be the focus of our review. We will compare the transverse surgical technique-a cut made parallel to the groin crease-versus the vertical groin incision surgical technique-classic technique: a surgical cut made across the groin crease-to access the femoral artery, in an attempt to determine which technique has the lower rate of complications, is safer and is more effective. OBJECTIVES: To evaluate the efficacy and safety of transverse groin incision compared with vertical groin incision for accessing the femoral artery in endovascular surgical procedures and open surgery. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases, and the World Health Organization (WHO) International Clinical Trials Registry Platform and ClinicalTrials.gov to 17 February 2020. The review authors searched the IBECS database to 26 March 2020 and reference lists of relevant studies/papers. SELECTION CRITERIA: We included randomized controlled trials (RCTs) and quasi-randomized trials (qRCTs) that compare transverse and vertical groin incision, during either endovascular or open surgery procedures. DATA COLLECTION AND ANALYSIS: Two review authors (MVCRC, FCN) independently selected the studies, assessed risk of bias, extracted data, performed data analysis and graded the certainty of evidence according to GRADE. MAIN RESULTS: We included one RCT and one qRCT in this review. These two studies had a combined total of 237 participants (283 groins). Infection of the surgical wound was the only outcome that was similar in both studies, and that could therefore be submitted to a combined analysis. Meta-analysis of the two studies showed low-certainty evidence that transverse groin incision resulted in a lower risk of surgical wound infection in the 10- to 28-day period following surgery (risk ratio [RR] 0.25, 95% confidence interval [CI] 0.08 to 0.76; 2 studies; 283 groin incisions). There was low heterogeneity between the studies. We downgraded the certainty of the evidence for surgical wound infection by one level due to serious limitations in the design (there was a high risk of bias in critical domains). The confidence interval for surgical wound infection is relatively wide, further indicating that the certainty of the effect estimate is low. This is likely due to the small number of studies and participants. We observed no evidence of a difference between the two surgical techniques for the other evaluated primary outcome 'lymphatic complications': lymphocele (RR 0.46, 95% CI 0.20 to 1.02; 1 study; 116 groins); and lymphorrhea (RR 2.77, 95% CI 0.92 to 8.34; 1 study; 116 groins). We downgraded the certainty of evidence for lymphatic complications by one level due to serious limitations in the design (there was a high risk of bias in critical domains); and by two further levels because of imprecision (small number of participants and only one study included). High-quality studies are needed to enable a comparison of the two surgical techniques with respect to other outcomes, such as infection of the vascular graft (endoprosthesis/prosthesis), prolonged hospitalization, reoperative surgery, death, neurological deficit (e.g. paresthesia), amputation, graft patency, and postoperative pain. AUTHORS' CONCLUSIONS: In this systematic review, we found low-certainty evidence that performing transverse groin incision to access the femoral artery resulted in fewer surgical wound infections compared with performing vertical groin incision. We observed no evidence of a difference between the two surgical techniques for the other evaluated outcomes (lymphocele and lymphorrhea). Other outcomes were not evaluated in these studies. Limitations of this systematic review are, however, the small sample size, short clinical follow-up period and high risk of bias in critical domains. For this reason, the applicability of the results is limited.

Stem cell therapy for treatment of thromboangiitis obliterans (Buerger's disease).

BACKGROUND: Thromboangiitis obliterans, also known as Buerger's disease, is a non-atherosclerotic, segmental inflammatory pathology that most commonly affects the small- and medium-sized arteries, veins, and nerves in the upper and lower extremities. The etiology is unknown, but involves hereditary susceptibility, tobacco exposure, immune and coagulation responses. In many cases, there is no possibility of revascularization to improve the condition. Stem cell therapy is an option for patients with severe complications, such as ischemic ulcers or rest pain. OBJECTIVES: To assess the effectiveness and safety of stem cell therapy in individuals with thromboangiitis obliterans (Buerger's disease). SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL and AMED databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 17 October 2017. The review authors searched the European grey literature OpenGrey Database, screened reference lists of relevant studies and contacted study authors. SELECTION CRITERIA: Randomized controlled trials (RCTs) or quasi-RCTs of stem cell therapy in thromboangiitis obliterans (Buerger's disease). DATA COLLECTION AND ANALYSIS: The review authors (DC, DM, FN) independently assessed the studies, extracted data and performed data analysis. MAIN RESULTS: We only included one RCT (18 participants with thromboangiitis obliterans) comparing the implantation of stem cell derived from bone marrow with placebo and standard wound dressing care in this review. We identified no studies that compared stem cell therapy (bone marrow source) versus stem cell therapy (umbilical cord source), stem cell therapy (any source) versus pharmacological treatment and stem cell therapy (any source) versus sympathectomy. Ulcer healing was assessed in the form of ulcer size. The mean ulcer area decreased more in the stem cell implantation group: from 5.04 cm2 (standard deviation (SD) 0.70) to 1.48 cm2 (SD 0.56) compared with the control group: mean ulcer size area decreased from 4.68 cm2 (SD 0.62) to 3.59 cm2 (SD 0.14); mean difference (MD) -2.11 cm2, 95% confidence interval (CI) -2.49 to -1.73; 1 study, 18 participants; very low-quality evidence. Pain-free walking distance showed more of an improvement in the stem cell implantation group: from mean of 38.33 meters (SD 17.68) to 284.44 meters (SD 212.12) compared with the control group: mean walking distance increased from 35.66 meters (SD 19.79) to 78.22 meters (SD 35.35); MD 206.22 meters, 95% CI 65.73 to 346.71; 1 study; 18 participants; very low-quality evidence.Outcomes such as rate of amputation, pain, amputation-free survival and adverse effects were not assessed.The quality of evidence was classified as very low, with only one study, small numbers of participants, high risk of bias in many domains and missing information regarding tobacco exposure status. AUTHORS' CONCLUSIONS: Very low-quality evidence suggests there may be an effect of the use of bone marrow-derived stem cells in the healing of ulcers and improvement in the pain-free walking distance in patients with Buerger's disease. High-quality trials assessing the effectiveness of stem cell therapy for treatment of patients with thromboangiitis obliterans (Buerger's disease) are needed.

Electron transport through dangling-bond silicon wires on H-passivated Si(100).

We compute the electron transmission through different types of dangling-bond wire on Si(100)-H (2 × 1). Recent progress in the construction of atomic-size interconnects (Weber et al 2012 Science 335 64) shows the possibility to achieve atomic-size circuits via atomic-size wires using silicon surfaces. Hence, electron transport through quasi-1D Si-based structures is a compelling reality. Prior to these achievements, wires formed by controlled desorption of passivating H atoms off the monohydride Si(100) surface have been shown to be subject to 1D correlations and instabilities (Hitosugi et al 1999 Phys. Rev. Lett. 82 4034). The present calculations are based on density functional theory and evaluate the electron transmission though the minimum-energy 1D structures that can be formed when creating dangling-bonds on Si(100)-(2 × 1)-H. The purpose of this study is twofold: (i) to assess the transport properties of these atomic-size wires in the presence of 1D instabilities; (ii) to provide a fingerprint for experimental identification of the instability through the transport characteristics of the wires. To these aims, we evaluate the electron transport through the wires in the absence of instabilities, in the presence of distortions (Jahn-Teller instabilities) and in the presence of magnetic instabilities (ferro- and antiferro-ordering). We find that instabilities substantially reduce the transport capabilities of dangling-bond wires leading to transmissions that vary so differently with electron energy that an unambiguous identification of the wire type should be accessible in transport experiments.

Electroresistance effect in ferroelectric tunnel junctions with symmetric electrodes.

Understanding the effects that govern electronic transport in ferroelectric tunnel junctions (FTJs) is of vital importance to improve the efficiency of devices such as ferroelectric memories with nondestructive readout. However, our current knowledge (typically based on simple semiempirical models or first-principles calculations restricted to the limit of zero bias) remains partial, which may hinder the development of more efficient systems. For example, nowadays it is commonly believed that the tunnel electroresistance (TER) effect exploited in such devices mandatorily requires, to be sizable, the use of two different electrodes, with related potential drawbacks concerning retention time, switching, and polarization imprint. In contrast, here we demonstrate at the first-principles level that large TER values of about 200% can be achieved under finite bias in a prototypical FTJ with symmetric electrodes. Our atomistic approach allows us to quantify the contribution of different microscopic mechanisms to the electroresistance, revealing the dominant role of the inverse piezoelectric response of the ferroelectric. On the basis of our analysis, we provide a critical discussion of the semiempirical models traditionally used to describe FTJs.

Electronic transport between graphene layers covalently connected by carbon nanotubes.

We present a first-principles study of the electronic transport properties of metallic and semiconducting carbon nanotube (CNT) junctions connecting two graphene layers, for different CNT lengths and link structures. Transport is analyzed in terms of the scattering states originated from the π and π* states of the finite-length CNTs, which couple to the graphene states producing resonances in the transmission curves. We find that, for metallic CNTs, the conductance is nearly independent of the tube length, but changes strongly with the link structure, while the opposite occurs for semiconducting CNTs, where the conductance in the tunneling regime is mainly controlled by the tube length and independent of the link structure. The sizable band offset between graphene and the CNTs yields to considerable effects on the transport properties, which cannot be captured using simple empirical models and highlights the need for a first-principles description.

Divacancies in graphene and carbon nanotubes.

Divacancies are among the most important defects that alter the charge transport properties of single-walled carbon nanotubes (SWNT), and we here study, using ab initio calculations, their properties. Two structures were investigated, one that has two pentagons side by side with an octagon (585) and another composed of three pentagons and three heptagons (555777). We investigate their stability as a function of tube diameter, and calculate their charge transport properties. The 585 defect is less stable in graphene due to two broken bonds in the pentagons. We estimate that the 555777 becomes more stable than the 585 for a diameter of about 40 A (53 A) for an armchair (zigzag) SWNTs, indicating that they will prevail in large diameter multiwalled carbon nanotubes and graphene ribbons.

Adsorption of benzene-1,4-dithiol on the Au(111) surface and its possible role in molecular conductance.

It is a consensus in the field of molecular electronics that the transport of charge across a single molecule depends sensitively on the details of the interaction between the molecule and the metallic leads, such as the molecular orientation. To advance the design of complex molecular devices, it is crucial to have a detailed understanding of these many aspects that influence the electron transport. A simple system that has been used as a paradigm of the class of conjugated aryl molecules is the benzene-1,4-dithiol (BDT). However, we still do not have a full understanding of the BDT transport experiments. Usually the geometries considered in transport calculations assumed that the BDT was connected to the two Au leads via the S atoms, and that the molecule was either perpendicular or close to a perpendicular configuration relative to the Au surfaces. Using ab initio calculations, we show that, for an isolated molecule, the configuration with largest adsorption energy has the BDT phenyl ring closer to being parallel to the surface, and we then argue, based on nonequilibrium Green's function-density functional theory calculations, that, depending on the experimental procedure, this may be the relevant configuration to be used in the transport calculations.

Oxygen clamps in gold nanowires.

We investigate how the insertion of an oxygen atom in an atomically thin gold nanowire can affect its rupture. We find, using ab initio total energy density functional theory calculations, that O atoms when inserted in gold nanowires form not only stable but also very strong bonds, in such a way that they can extract atoms from a stable tip, serving in this way as a clamp that could be used to pull a string of gold atoms.

Effect of impurities in the large Au-Au distances in gold nanowires.

Experimentally obtained atomically thin gold nanowires have presented exceedingly large Au-Au interatomic distances before they break. Since no theoretical calculations of pure gold nanowires have been able to produce such large distances, we have investigated, through ab initio calculations, how impurities could affect them. We have studied the effect of H, B, C, N, O, and S impurities on the nanowire electronic and structural properties, in particular how they affect the maximum Au-Au bond length. We find that the most likely candidates to explain the distances in the range of 3.6 A and 4.8 A are H and S impurity atoms, respectively.

Esteatose hepática aguda da gravidez - revisão da literatura / Acute fatty liver of pregnancy - review of the literature

A esteatose hepática aguda da gravidez (EHAG) é uma doença pouco frequente, mas não rara, incidindo em uma a cada 13.000 gestações. Acomete jovens primíparas no final do 3o. trimestre de gravidez e apresenta relações com feto do sexo masculino e/ou gestação gemelar. Pode estar associada com pré-eclâmpsia (PE), síndrome HELLP (havendo dúvidas entre essa associação e a causa da EHAG) e colestase intra-hepática da gravidez (CIHG). Alguns estudos relacionam a etiologia da EHAG com lesões mitocondriais e deficiências enzimáticas que podem trazer sérias consequências ao recém-nato, levando-o inclusive ao óbito. Sua baixa recorrência depõe contra possível etiologia genético-metabólica, podendo-se postular origem multifatorial desta afecção. Entre seus diagnósticos diferenciais estão PE, CIHG, hepatites virais e outras causas de insuficiência hepática aguda com infiltração gordurosa hepática. Seu tratamento inclui interrupção da gestação e medidas de suporte de terapia intensiva, sendo raros os relatos de recorrência. As mortalidades do feto e da mãe situam-se respectivamente em torno de 10 por cento e 33 por cento. Raramente esta afecção leva à necessidade de transplante de hapático