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BACKGROUND: Endovascular aneurysm repair (EVAR) success depends on imaging technology both in the planning and operative phases. Endovascular repair requires intravenous contrast and radiation exposure to the patient as well as radiation exposure to the operator. Recent developments in imaging technology attempt to merge preoperative imaging with intraoperative imaging to improve the efficiency and accuracy of EVAR. The Cydar 3-dimensional (3D) imaging system combines the preoperative and intraoperative imaging during the operation. We aim to investigate the use of the Cydar 3D imaging system during EVAR compared to conventional methods. METHODS: Retrospective review of all patients undergoing an EVAR at a single quaternary vascular center from 2019-2023 was collected. This cohort was divided into 2 groups: (1) repair using Cydar 3D imaging or (2) repair without Cydar 3D imaging. Overall, 138 unique patients were identified with 27 operations using Cydar 3D imaging and 111 operations without Cydar 3D imaging. We performed a 1-to-1 propensity score-matched analysis using nearest-neighbor matching for variables including age, case urgency, and if the case was performed in the operative room or interventional radiology room. A match occurred when a patient in the Cydar 3D imaging group had an estimated score within 0.01 standard deviations of a patient in the control group. From this, we paired 27 from each cohort for a total of 54 patients. Demographic data included length of stay in days, contrast volume (mL), fluoroscopy time (min), procedure length (mins), mortality, and blood loss (mL). Univariate analyses were performed and a P value less than 0.05 was considered statistically significant. RESULTS: A total of 54 vascular patients were analyzed: 27 without the Cydar 3D imaging and 27 with the Cydar 3D imaging. In the univariate analysis, there was no statistical difference in the average length of stay (6.4 days ± 11.76 vs. 4.1 ± 6.03, P = 0.372), aneurysm size (5.9 ± 1.4 vs. 5.9 ± 1.2, P = 0.88), contrast volume in mL (91.3 ± 47.0 vs. 91.1-33.49, P = 9.88), fluoroscopy time in mins (20.2 ± 17.2 vs. 19.5 ± 19.4, P = 0.89), procedure length (299.3 ± 177.9 vs. 353 ± 191.98, P = 0.279), and blood loss in mL (513.8 ± 791 vs. 353 ± 191.98, P = 0.594). There was an increase in reintervention for endoleaks in the group with use of Cydar 3D imaging (0 vs. 6, P = 0.043). A subanalysis of patients undergoing physician-modified EVARs did show a 15% reduction in the contrast volume used. CONCLUSIONS: The use of 3D imaging technology has the potential to increase the safety of EVAR to both patients and operators. In our study, we did not find any difference in standard EVARs; however, there was a contrast use decrease in physician-modified EVARs. Further studies will need to be performed to determine the realized benefit from performing EVARs using this new technology.
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Implante de Prótese Vascular , Angiografia por Tomografia Computadorizada , Procedimentos Endovasculares , Imageamento Tridimensional , Valor Preditivo dos Testes , Interpretação de Imagem Radiográfica Assistida por Computador , Humanos , Estudos Retrospectivos , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/instrumentação , Feminino , Masculino , Idoso , Implante de Prótese Vascular/efeitos adversos , Implante de Prótese Vascular/instrumentação , Resultado do Tratamento , Idoso de 80 Anos ou mais , Fatores de Tempo , Aortografia , Fatores de Risco , Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aneurisma Aórtico/diagnóstico por imagem , Aneurisma Aórtico/cirurgia , Cirurgia Assistida por Computador/efeitos adversos , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/diagnóstico por imagemRESUMO
The world's hunger for novel food ingredients drives the development of safe, sustainable, and nutritious novel food products. For foods containing novel proteins, potential allergenicity of the proteins is a key safety consideration. One such product is a fungal biomass obtained from the fermentation of Rhizomucor pusillus. The annotated whole genome sequence of this strain was subjected to sequence homology searches against the AllergenOnline database (sliding 80-amino acid windows and full sequence searches). In a stepwise manner, proteins were designated as potentially allergenic and were further compared to proteins from commonly consumed foods and from humans. From the sliding 80-mer searches, 356 proteins met the conservative >35% Codex Alimentarius threshold, 72 of which shared ≥50% identity over the full sequence. Although matches were identified between R. pusillus proteins and proteins from allergenic food sources, the matches were limited to minor allergens from these sources, and they shared a greater degree of sequence homology with those from commonly consumed foods and human proteins. Based on the in silico analysis and a literature review for the source organism, the risk of allergenic cross-reactivity of R. pusillus is low.
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Alérgenos , Biomassa , Rhizomucor , Alérgenos/imunologia , Rhizomucor/imunologia , Humanos , Ingredientes de Alimentos , Simulação por Computador , Hipersensibilidade Alimentar/imunologia , Proteínas Fúngicas/imunologiaRESUMO
BACKGROUND: COVID-19 was initially identified as an acute respiratory disease, but it was quickly recognized that multiple organ systems could be affected. Venous thrombosis and pulmonary embolism have been well reported. However, there is a paucity of data on COVID-19-related arterial thrombosis. We examined the incidence, characteristics, treatment, and outcome in patients with acute COVID-19-related arterial thrombosis in a large health maintenance organization (HMO). METHODS: A retrospective multicenter case review was performed from March 2020 to March 2021. Cases were identified through a questionnaire sent to vascular surgeons. Patient characteristics, imaging, treatment, and outcome were reviewed. Successful revascularization was defined as restoration of blood flow with viability of the end organ and absence of death within 30 days. Limb salvage was defined as prevention of major amputation (transtibial or transfemoral) and absence of death in 30 days. RESULTS: There were 37,845 patients admitted with COVID-19 complications during this time. Among this group, 26 patients (0.07%) had COVID-19-related arterial thrombosis. The mean age was 61.7 years (range, 33-82 years) with 20 men (77%) and 6 women (23%). Ethnic minorities comprised 25 of 26 cases (96%). Peripheral arterial disease (PAD) was present in 4 of 26 (15%), active smoking in 1 of 26 (3.8%), and diabetes in 19 of 26 (73%) cases. Most patients developed acute arterial ischemia in the outpatient setting, 20 of 26 (77%). Of the outpatients, 6 of 20 (30%) had asymptomatic COVID-19 and 14 of 20 (70%) had only mild upper respiratory symptoms. Distribution of ischemia was as follows: 23 patients had at least one lower extremity ischemia, one patient had cerebral and lower extremity, one had mesenteric and lower extremity, and one had upper extremity ischemia. Revascularization was attempted in 21 patients, of which 12 of 21 (57%) were successful. Limb salvage was successful in 13 of 26 (50%) patients. The overall mortality was 31% (8/26). CONCLUSIONS: Our experience in a large HMO revealed that the incidence of COVID-19-related arterial thrombosis was low. The actual incidence is likely to be higher since our method of case collection was incomplete. The majority of arterial thrombosis occurred in the outpatient setting in patients with asymptomatic or mild/moderate COVID-19 respiratory disease. Acute ischemia was the inciting factor for hospitalization in these cases. Acute lower extremity ischemia was the most common presentation, and limb salvage rate was lower than that expected when compared to ischemia related to PAD. Arterial thrombosis associated with COVID-19 portends a significantly higher mortality. Education of primary care providers is paramount to prevent delayed diagnosis as most patients initially developed ischemia in the outpatient setting and did not have a high cardiovascular risk profile.
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Arteriopatias Oclusivas , COVID-19 , Doença Arterial Periférica , Trombose , Amputação Cirúrgica/efeitos adversos , Arteriopatias Oclusivas/diagnóstico por imagem , Arteriopatias Oclusivas/epidemiologia , Arteriopatias Oclusivas/cirurgia , COVID-19/complicações , Feminino , Sistemas Pré-Pagos de Saúde , Humanos , Isquemia/diagnóstico por imagem , Isquemia/etiologia , Isquemia/terapia , Salvamento de Membro/efeitos adversos , Extremidade Inferior/irrigação sanguínea , Masculino , Pessoa de Meia-Idade , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/epidemiologia , Doença Arterial Periférica/terapia , Estudos Retrospectivos , Fatores de Risco , Trombose/complicações , Trombose/diagnóstico por imagem , Trombose/terapia , Resultado do TratamentoRESUMO
Emulsifiers are commonly used in food processing for the technological purpose of altering the flavor or to improve the texture of foods. Due to their ubiquity, these substances are consumed daily at low levels in the human diet. Recently published in vitro and in vivo studies suggest dietary exposure to emulsifiers modulate the gut microbiota and contribute to the increasing prevalence of metabolic disease. A literature search was conducted which identified eight studies investigating the interaction of sodium carboxymethyl cellulose, polysorbate 80, gum arabic, carrageenan, and arabinogalactan with the gut microbiota in murine and in vitro models. Numerous inconsistent changes in various phyla and genera were identified. These studies were conducted at high doses that have no relevance to the current dietary levels consumed in the United States. Subtle changes in gut microbiota composition as a toxicological endpoint is not supported by established internationally recognized toxicology testing guidelines. Therefore, the results of these studies are difficult to interpret and extrapolate to humans and are not supported by previous safety conclusions of international food safety authorities. The current understanding of the gut microbiota is that the structure is highly dynamic and is heavily influenced by the diet. Thus, the results of these studies may not necessarily suggest a safety concern, but rather reflect an adaptive response of the gut microbiota to an external stressor. Future research will need to further elucidate the mechanisms of metabolic disease in rodents and humans and establish clinically relevant and reliable endpoints to assess changes in gut microflora.
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Autogenous arteriovenous fistula (AVF) is the primary recommended access for hemodialysis. Long-term use will not uncommonly result in AVF aneurysmal degeneration. Aneurysm-associated complications encompass pain, skin ulceration, infection, thrombosis, cannulation difficulties, and life-threatening bleeding. Various methods to repair aneurysmal AVFs have been described. However, there may be circumstances when this is not possible and require insertion of a temporary hemodialysis catheter (HDC) until a new arteriovenous access is created. We describe a case series of creating a new simultaneous AVF while continuing to use the primary failing aneurysmal AVF to avoid placement of an HDC. Once the new AVF becomes operational, the primary aneurysmal AVF can be abandoned. Six patients underwent simultaneous new AVF creation, 4 ipsilateral, and 2 contralateral. None of the patients developed symptomatic steal syndrome or congestive heart failure. Five of 6 patients had successful usage of the new AVF, and subsequently underwent ligation and excision of the aneurysmal AVF, thus avoiding a temporary HDC. Close monitoring for skin compromise and bleeding in the aneurysmal AVF is recommended while the new AVF matures.
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Aneurisma/etiologia , Derivação Arteriovenosa Cirúrgica/métodos , Falência Renal Crônica/terapia , Diálise Renal , Extremidade Superior/irrigação sanguínea , Aneurisma/diagnóstico por imagem , Aneurisma/cirurgia , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Velocidade do Fluxo Sanguíneo , Humanos , Ligadura , Fluxo Sanguíneo Regional , Estudos Retrospectivos , Fatores de Tempo , Falha de Tratamento , Ultrassonografia Doppler em Cores , Grau de Desobstrução VascularRESUMO
The potential toxicity of two savory food ingredients produced by fermentation of enzymatically hydrolyzed corn starch (Savory Base 100 and Savory Base 200) was evaluated individually in a bacterial reverse mutation assay, an in vitro mammalian cell gene mutation assay, an acute oral study and as a mixture in a 90-day dietary study. In the bacterial reverse mutation and in vitro mammalian cell gene mutation assays, neither ingredient was mutagenic at concentrations up to 5000 µg/plate and 5000 µg/mL, respectively in the presence and absence of metabolic activation. In the acute study, the no-observed-adverse-effect level (NOAEL) for each Savory Base 100 and Savory Base 200 in male and female rats was 2000 mg/kg body weight. In the 90-day study, the hematology and clinical chemistry findings and histopathological changes noted in the liver, heart and kidneys were deemed to be of no toxicological significance, as the mean values were within the historical control range, were not dose-dependent, occurred at a similar frequency in control groups, or only occurred in the control group. Considering these findings, the NOAEL for Savory Base 100 and Savory Base 200 was 2333 and 1167 mg/kg body weight, respectively, the highest dose tested in each case.
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Ingredientes de Alimentos/toxicidade , Satureja/toxicidade , Testes de Toxicidade Aguda , Testes de Toxicidade Subcrônica , Animais , Dano ao DNA , Feminino , Fermentação , Coração/efeitos dos fármacos , Rim/efeitos dos fármacos , Fígado/efeitos dos fármacos , Masculino , Testes de Mutagenicidade , Mutagênicos/administração & dosagem , Mutagênicos/toxicidade , Nível de Efeito Adverso não Observado , RatosRESUMO
To assess the potential safety of lipid soluble green tea extract, also referred to as lipid soluble tea polyphenols (LSTP), a series of genotoxicity tests were conducted, including an Ames, in vivo mouse micronucleus, and in vivo mouse sperm abnormality test. The toxicity of LSTP was evaluated in 90- and 30-day feeding studies. LSTP did not show mutagenic activity in the Ames test and no genotoxic potential in the in vivo assays at doses up to 10 g/kg body weight (bw). In the 90-day feeding study, LSTP was given in the diet at levels providing 0, 0.125, 0.25, or 0.50 g/kg bw/day. No significant effects were noted on body weight, food consumption, hematology, clinical chemistry, organ weights, and histopathological examination. The no-observed-adverse-effect level (NOAEL) was therefore considered to be 0.50 g/kg bw/day, the highest dose tested. Likewise, dosing of SD rats by gavage for 30 days also showed no adverse effects of growth, hematology, clinical chemistry, organ weights, or histopathology at doses of 0.58, 1.17, and 2.33 g/kg bw/day. The NOAEL in the 30-day study was considered to be the highest dose tested. These data provide evidence to support the safe use of LSTP in food.
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Extratos Vegetais/toxicidade , Polifenóis/toxicidade , Chá/toxicidade , Animais , Lipídeos , Camundongos , Testes de Mutagenicidade , Nível de Efeito Adverso não Observado , Extratos Vegetais/administração & dosagem , Polifenóis/administração & dosagem , Ratos , Ratos Sprague-Dawley , Chá/químicaRESUMO
Euglena gracilis is a microalga capable of synthesizing various nutrients of interest in human and animal nutrition. When cultivated aerobically in the dark, Euglena synthesize paramylon, a storage polysaccharide comprised of high molecular weight beta-1,3-D-glucose polymers organized in cytoplasmic granules. Beta-glucans have been shown to have immune modulation effects, including anti-microbial, anti-tumor, and anti-oxidant properties, and metabolic effects, such as regulation of cholesterol and blood sugar levels. Preparations of E. gracilis and paramylon may therefore have potential utility as functional food ingredients for human and animal nutrition. A battery of toxicological studies was conducted on a dried preparation of E. gracilis and paramylon to support their safe food use. The dried alga was not genotoxic in a bacterial reverse mutation test and mammalian micronucleus test. In the subchronic toxicity study, rats were provided E. gracilis in the diet at levels of 0, 12,500, 25,000 or 50,000 ppm. Paramylon was provided at a concentration of 50,000 ppm. No effects that could be attributable to treatment were observed in clinical observations, body weight, food consumption, ophthalmology, hematology and clinical chemistry, urinalysis, and macroscopic and microscopic findings. A NOAEL of 50,000 ppm in the diet was determined for both ingredients.
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Euglena gracilis/metabolismo , Inocuidade dos Alimentos , Alimento Funcional/toxicidade , Glucanos/toxicidade , Testes de Mutagenicidade/métodos , Testes de Toxicidade Subcrônica/métodos , Administração Oral , Animais , DNA Bacteriano/efeitos dos fármacos , DNA Bacteriano/genética , Dessecação , Relação Dose-Resposta a Droga , Feminino , Glucanos/administração & dosagem , Glucanos/metabolismo , Humanos , Masculino , Micronúcleos com Defeito Cromossômico/induzido quimicamente , Testes para Micronúcleos , Mutagênese , Nível de Efeito Adverso não Observado , Pós , Ratos Sprague-Dawley , Medição de Risco , Fatores de TempoRESUMO
Marine oils are rich in polyunsaturated fatty acids (PUFAs), including docosahexaenoic and eicosapentaenoic acid. These PUFAs are associated with health benefits and additional sustainable sources of marine oils are desirable. One of the source organisms is Calanus finmarchicus, a copepod endemic to the North Atlantic. PUFAs in the lipid fraction of this organism are largely in the form of wax esters. To assess the safety of these wax esters as a source of PUFAs, a randomized, double-blinded, placebo-controlled clinical trial was conducted whereby 64 subjects consumed 2 g Calanus oil in capsule form daily for a period of one year. A group of 53 subjects consumed placebo capsules. At baseline, 6-, and 12-months, series of evaluations were conducted, including: vital signs, clinical chemistry and hematological evaluations, and adverse event reporting. Food intake and physical exercise were controlled by means of a questionnaire. There were no effects on Calanus oil treatment on any of the safety parameters measured. A slight increase in the incidence of eczema was reported in the Calanus oil group, but the response was minor in nature, not statistically significant after controlling for multiple comparisons, and could not be attributed to treatment.
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Copépodes/química , Suplementos Nutricionais , Ésteres/uso terapêutico , Ácidos Graxos Insaturados/uso terapêutico , Ceras/uso terapêutico , Administração Oral , Adulto , Idoso , Animais , Cápsulas , Suplementos Nutricionais/efeitos adversos , Método Duplo-Cego , Ésteres/administração & dosagem , Ésteres/efeitos adversos , Ésteres/isolamento & purificação , Ácidos Graxos Insaturados/administração & dosagem , Ácidos Graxos Insaturados/efeitos adversos , Ácidos Graxos Insaturados/isolamento & purificação , Feminino , Teste de Tolerância a Glucose , Humanos , Masculino , Pessoa de Meia-Idade , Noruega , Segurança do Paciente , Medição de Risco , Inquéritos e Questionários , Fatores de Tempo , Resultado do Tratamento , Ceras/efeitos adversos , Ceras/isolamento & purificação , Adulto JovemRESUMO
We demonstrate a sub-centimeter spatial resolution fiber-based distributed temperature sensor with enhanced measurement accuracy and reduced acquisition time. Our approach employs time domain analysis of backscattered Stokes and anti-Stokes photons generated via spontaneous Raman scattering in a chalcogenide (ChG) As2S3 fiber for temperature monitoring. The sensor performance is significantly improved by exploiting the high Raman coefficient and increased refractive index of the ChG fiber. We achieve a temperature uncertainty of ± 0.65 °C for a short measurement time of only 5 seconds; whilst the detection uncertainty is less than ± 0.2 °C for a longer integration time of 2 minutes. We also investigate the optimum Stokes and anti-Stokes bands for optimal sensing performance. Our theoretical analysis shows that a small detuning frequency regime from a pump is more suitable for rapid measurements while a large detuning regime provides higher temperature resolution.
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Calcogênios/química , Tecnologia de Fibra Óptica/instrumentação , Análise Espectral Raman/instrumentação , Termografia/instrumentação , Transdutores , Desenho de Equipamento , Análise de Falha de EquipamentoRESUMO
INTRODUCTION: Patients with complex aortic anatomy require meticulous surgical planning to optimize intraoperative and postoperative outcomes. The GORE Excluder Conformable Abdominal Aortic Aneurysm Endoprosthesis (CEXC Device, WL Gore and Associates, Flagstaff, AZ) allows for endovascular treatment of highly angulated and short proximal neck abdominal aortic aneurysms (AAA). Owing to its recent approval, short-term clinical outcomes of this device remain scarce. REPORT: In this report, we present a case series of 3 patients who underwent endovascular aortic repair using the GORE Excluder Conformable device with highly angulated (>70°) aortic neck anatomy. Endografts were deployed in a radiology suite using standard 2D angiography in conjunction with a CYDAR Medical (Wilmington, Delaware) reconstructed 3D overlay. The patients' ages were 85, 67, and 85 years. The mean abdominal aortic aneurysm diameter in these cases was 6.9 cm. The mean proximal neck length was 2.1 cm, proximal mean neck angulation was 83°. The mean operative time, total fluoroscopy time, and contrast used were 208 minutes, 28.3°minutes, and 94.5 milliliters, respectively. No adjunctive procedures, such as proximal cuff or endo-anchors, were performed at the time of index procedure. DISCUSSION: Type Ia endoleak was observed in 1 patient post-operatively but after treatment with an aortic cuff there was no evidence of enlarging aneurysm sac. The GORE Excluder Conformable Endoprosthesis expands access to endovascular management of AAAs. Our early experience with this device demonstrated excellent patient and clinical outcomes in a highly angulated neck anatomy.
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Aneurisma da Aorta Abdominal , Implante de Prótese Vascular , Procedimentos Endovasculares , Desenho de Prótese , Stents , Idoso , Idoso de 80 Anos ou mais , Humanos , Aneurisma da Aorta Abdominal/cirurgia , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Aortografia , Prótese Vascular , Implante de Prótese Vascular/instrumentação , Angiografia por Tomografia Computadorizada , Procedimentos Endovasculares/instrumentação , Fatores de Tempo , Resultado do TratamentoRESUMO
To address the growing world population and reduce the impact of environmental changes on the global food supply, ingredients are being produced using microorganisms to yield sustainable and innovative products. Food ingredients manufactured using modern biotechnology must be produced by non-toxigenic and nonpathogenic production organisms that do not harbor antimicrobial resistance (AMR). Several fungal species represent attractive targets as sources of alternative food products. One such product is a fungal biomass obtained from the fermentation of Rhizomucor pusillus strain CBS 143028. The whole genome sequence of this strain was annotated and subjected to sequence homology searches and in silico phenotype prediction tools to identify genetic elements encoding for protein toxins active via oral consumption, virulence factors associated with pathogenicity, and determinants of AMR. The in silico investigation revealed no genetic elements sharing significant sequence homology with putative virulence factors, protein toxins, or AMR determinants, including the absence of mucoricin, an essential toxin in the pathogenesis of mucormycosis. These in silico findings were corroborated in vitro based on the absence of clinically relevant mycotoxin or antibacterial secondary metabolites. Consequently, it is unlikely that R. pusillis strain CBS 143028 would pose a safety concern for use in food for human consumption.
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Ingredientes de Alimentos , Humanos , Biomassa , Rhizomucor/genéticaRESUMO
BACKGROUND: This study was conducted to determine the effect of ultrasound (US)-guided percutaneous access for percutaneous endovascular abdominal aortic aneurysm repair (PEVAR) on conversion to open repair by femoral cutdown. We also sought to identify other risk factors associated with failure of percutaneous access and conversion to femoral cutdowns. METHODS: This is a single-center, retrospective review of 101 patients who underwent PEVAR between January 1, 2005 and July 31, 2009 (56 months). Risk factors that were evaluated for unsuccessful PEVAR included gender, age (≤65 and ≥66 years), US-guided percutaneous access, mechanical failure, abdominal aortic aneurysm size, and the following comorbidities: diabetes, hypertension, vessel calcification, and obesity (body mass index: ≥30 kg/m(2)). RESULTS: There were 10 (9.9%) conversions from percutaneous to femoral cutdown, yielding a success rate of 90.1% for a total percutaneous approach. Each converted patient had one groin converted, resulting in a cutdown rate per groin of 10/202 (5%). There were no 30-day mortalities. Univariate analysis showed that hypertension (P = 0.261), age ≥66 years (P = 0.741), current smoking history (P = 0.649), past smoking history (P = .093), diabetes (P = 0.908), vessel calcification (P = 0.8281), and body mass index ≥30 kg/m(2) (P = 0.052) did not significantly predict conversion to endovascular aortic aneurysm repair (EVAR). Mechanical failure significantly predicted conversion to cutdown EVAR (P = 0.0002), whereas US-guided percutaneous access influenced successful PEVAR (P = 0.030). Multivariate analysis showed that mechanical failure significantly predicted conversion to cutdown EVAR (P = 0.003) and US-guided percutaneous access influenced successful PEVAR (P = 0.040) after adjusting for smoking history and obesity. CONCLUSION: PEVAR is a viable option for aortic aneurysm repair that may be improved with US-guided percutaneous access by reducing the rate of femoral cutdowns.
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Aneurisma da Aorta Abdominal/cirurgia , Implante de Prótese Vascular , Procedimentos Endovasculares , Sistemas Pré-Pagos de Saúde , Ultrassonografia de Intervenção , Idoso , Idoso de 80 Anos ou mais , Aneurisma da Aorta Abdominal/diagnóstico por imagem , Implante de Prótese Vascular/efeitos adversos , California , Distribuição de Qui-Quadrado , Bases de Dados Factuais , Procedimentos Endovasculares/efeitos adversos , Feminino , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/cirurgia , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Reoperação , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Ultrassonografia de Intervenção/efeitos adversosRESUMO
We report the demonstration of automatic higher-order dispersion compensation for the transmission of 275 fs pulses associated with a Tbaud Optical Time Division Multiplexed (OTDM) signal. Our approach achieves simultaneous automatic compensation for 2nd, 3rd and 4th order dispersion using an LCOS spectral pulse shaper (SPS) as a tunable dispersion compensator and a dispersion monitor made of a photonic-chip-based all-optical RF-spectrum analyzer. The monitoring approach uses a single parameter measurement extracted from the RF-spectrum to drive a multidimensional optimization algorithm. Because these pulses are highly sensitive to fluctuations in the GVD and higher orders of chromatic dispersion, this work represents a key result towards practical transmission of ultrashort optical pulses. The dispersion can be adapted on-the-fly for a 1.28 Tbaud signal at any place in the transmission line using a black box approach.
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Algoritmos , Desenho Assistido por Computador , Compressão de Dados/métodos , Modelos Teóricos , Dispositivos Ópticos , Processamento de Sinais Assistido por Computador/instrumentação , Telecomunicações/instrumentação , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de Radiação , Radiação TerahertzRESUMO
We demonstrate on-chip all-optical pulse erasure based on four-wave mixing and cross-phase modulation in a dispersion engineered chalcogenide (As(2)S(3)) rib waveguide. We achieve an erasure efficiency of ~15 dB for picosecond pulses in good agreement with numerical simulations using the nonlinear Schrödinger equation. The combined effect of the high instantaneous optical nonlinearity (γ = 9900 (W km)(-1)) and small group-velocity dispersion (D = 29 ps/nm km), which reduces pulse walk-off, will enable all-optical pulse erasure for ultrafast signal processing.
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We demonstrate a photonic chip-based all-optical exclusive-OR (XOR) gate for phase-encoded optical signals via four-wave mixing in a highly nonlinear, dispersion-engineered chalcogenide (As2S3) planar waveguide. We achieve error-free, XOR operation for 40 Gbit/s differential phase shift keying (DPSK) optical signals with no power penalty. The effectiveness and broad bandwidth operation of our approach is highlighted by implementing an XOR gate for 160 Gbit/s DPSK signals.
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We show the first simultaneous OSNR monitoring of two 40 Gb/s OOK and DPSK channels, using only a wavelength selective switch and two slow photodetectors. Our approach is modulation format and bit-rate independent and can easily be included in existing reconfigurable networks.
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We demonstrate a terahertz bandwidth silicon nanowire based radio-frequency spectrum analyzer using cross-phase modulation. We show that the device provides accurate characterization of 640Gbaud on-off-keyed data stream and demonstrate its potential for optical time-division multiplexing optimization and optical performance monitoring of ultrahigh speed signals on a silicon chip. We analyze the impact of free carrier effects on our device, and find that the efficiency of the device is not reduced by two-photon or free-carrier absorption, nor its accuracy compromised by free-carrier cross-chirp.
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Redes de Comunicação de Computadores/instrumentação , Nanotubos/química , Dispositivos Ópticos , Processamento de Sinais Assistido por Computador/instrumentação , Silício/química , Telecomunicações/instrumentação , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Ondas de Rádio , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
We present automatic dispersion control of 1.28Tb/s optical time domain multiplexed signals. The dispersion is monitored by measuring the power of the 1.28THz tone of the RF spectrum using a photonic-chip-based radio-frequency spectrum analyzer (PC-RFSA) and the dispersion compensation is realized by means of a spectral pulse shaper, via computer-controlled feedback from the PC-RFSA.
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Ilio-iliac arteriovenous (AV) fistula is a rare complication after lumbar diskectomy. Endovascular repair of such fistulas is a growing trend in vascular surgery. This is a case report of an endovascular exclusion of an ilio-iliac AV fistula in a 51-year-old male. This man presented with high-output congestive heart failure and ascites. The AV fistula was discovered 17 years after a lumbar diskectomy. Computed topography (CT) revealed a right common iliac artery pseudoaneurysm connecting to the left common iliac vein. The fistula was repaired using a bifurcated Gore Excluder endograft. There were follow-up CT scans at 6 and 10 months confirming exclusion of the AV fistula. Endovascular AV fistula repair offers a safe, effective method for managing ilio-iliac AV fistulas.