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1.
J Korean Soc Radiol ; 85(3): 566-578, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38873383

RESUMO

Purpose: This study investigated whether the respiratory phase during pleural puncture in CT-guided percutaneous transthoracic needle biopsy (PTNB) affects complications. Materials and Methods: We conducted a retrospective review of 477 lung biopsy CT scans performed during free breathing. The respiratory phases during pleural puncture were determined based on the table position of the targeted nodule using CT scans obtained during free breathing. We compared the rates of complications among the inspiratory, mid-, and expiratory respiratory phases. Logistic regression analysis was performed to control confounding factors associated with pneumothorax. Results: Among the 477 procedures, pleural puncture was performed during the expiratory phase in 227 (47.6%), during the mid-phase in 108 (22.6%), and during the inspiratory phase in 142 (29.8%). The incidence of pneumothorax was significantly lower in the expiratory puncture group (40/227, 17.6%; p = 0.035) and significantly higher in the mid-phase puncture group (31/108, 28.7%; p = 0.048). After controlling for confounding factors, expiratory-phase puncture was found to be an independent protective factor against pneumothorax (odds ratio = 0.571; 95% confidence interval = 0.360-0.906; p = 0.017). Conclusion: Our findings suggest that pleural puncture during the expiratory phase may reduce the risk of pneumothorax during image guided PTNB.

2.
PLoS One ; 18(9): e0291195, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37751461

RESUMO

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with chronic, progressive lung fibrosis with a poor prognosis. Recent studies have reported a high prevalence of obstructive sleep apnea (OSA) in IPF patients and an association with poor prognosis. This study aimed to evaluate the prevalence, risk factors, and clinical effects on mortality of OSA in patients with IPF. METHODS: Clinical data were retrospectively analyzed in 167 patients with IPF at Haeundae-Paik Hospital, Republic of Korea. A type 4 portable device was used to monitor OSA, and an apnea-hypopnea index of 5 events per sleep hour and above was diagnosed as OSA. RESULTS: The mean follow-up period and age were 26.9 months and 71.4 years, respectively, with male predominance. OSA was confirmed in 108 patients (64.7%). Mild OSA was the most common (62.1%). Independent risk factors for OSA in the multivariate logistic regression analysis were age (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.02-1.13, p = 0.007), body weight (OR 1.05, 95% CI 1.02-1.09, p = 0.002), and risk based on the Berlin questionnaire (OR 2.76, 95% CI 1.12-6.80, p = 0.028). Shorter six-minute walk distance (6MWD) (hazard ratio [HR] 1.00, 95% CI: 1.00-1.00, p < 0.001), acute exacerbation (AE) (HR 13.83, 95% CI: 5.71-33.47, p < 0.001), and higher percentage of cumulative time with oxygen saturation below 90% in total sleep time (HR 1.08, 95% CI: 1.02-1.14, p = 0.007) were risk factors for mortality in IPF patients in the Cox regression analysis. CONCLUSION: Approximately two-thirds of the IPF patients had OSA. Older age, higher body weight, and high risk based on the Berlin questionnaire were independent risk factors for OSA in IPF patients. Shorter 6MWD, experience of AE, and night hypoxemia during sleep were associated with a higher risk of mortality in patients with IPF.


Assuntos
Fibrose Pulmonar Idiopática , Apneia Obstrutiva do Sono , Humanos , Masculino , Feminino , Estudos Retrospectivos , Prevalência , Fibrose Pulmonar Idiopática/complicações , Fibrose Pulmonar Idiopática/epidemiologia , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/epidemiologia , Peso Corporal
3.
Neurology ; 100(8): e822-e833, 2023 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-36443016

RESUMO

BACKGROUND AND OBJECTIVES: While chronological age is one of the most influential determinants of poststroke outcomes, little is known of the impact of neuroimaging-derived biological "brain age." We hypothesized that radiomics analyses of T2-FLAIR images texture would provide brain age estimates and that advanced brain age of patients with stroke will be associated with cardiovascular risk factors and worse functional outcomes. METHODS: We extracted radiomics from T2-FLAIR images acquired during acute stroke clinical evaluation. Brain age was determined from brain parenchyma radiomics using an ElasticNet linear regression model. Subsequently, relative brain age (RBA), which expresses brain age in comparison with chronological age-matched peers, was estimated. Finally, we built a linear regression model of RBA using clinical cardiovascular characteristics as inputs and a logistic regression model of favorable functional outcomes taking RBA as input. RESULTS: We reviewed 4,163 patients from a large multisite ischemic stroke cohort (mean age = 62.8 years, 42.0% female patients). T2-FLAIR radiomics predicted chronological ages (mean absolute error = 6.9 years, r = 0.81). After adjustment for covariates, RBA was higher and therefore described older-appearing brains in patients with hypertension, diabetes mellitus, a history of smoking, and a history of a prior stroke. In multivariate analyses, age, RBA, NIHSS, and a history of prior stroke were all significantly associated with functional outcome (respective adjusted odds ratios: 0.58, 0.76, 0.48, 0.55; all p-values < 0.001). Moreover, the negative effect of RBA on outcome was especially pronounced in minor strokes. DISCUSSION: T2-FLAIR radiomics can be used to predict brain age and derive RBA. Older-appearing brains, characterized by a higher RBA, reflect cardiovascular risk factor accumulation and are linked to worse outcomes after stroke.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Encéfalo/diagnóstico por imagem , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/complicações , AVC Isquêmico/complicações , Imageamento por Ressonância Magnética/métodos , Acidente Vascular Cerebral/complicações
4.
J Clin Med ; 11(14)2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35887974

RESUMO

Our aim is to assess the optimal levels of oxygen and carbon dioxide for the prognosis of favorable neurologic outcomes in survivors after extracorporeal cardiopulmonary resuscitation (ECPR). We obtained the mean levels of PaCO2 and PaO2 in arterial blood gas samples 72 h after ECPR. The primary outcome was the neurological status, according to the Cerebral Performance Categories (CPC) scale, upon discharge. Of 119 (48.6%) survivors, 95 (38.8%) had favorable neurologic outcomes (CPC 1 or 2). There was a U-shaped relationship between mean arterial blood gas tensions and poor neurological outcomes. The risk of poor neurological outcome was lowest in patients with the second tertile of mean PaCO2 (30-42 mm Hg) and PaO2 (120-160 mm Hg). In a multivariable analysis, third tertile of mean PaCO2, third tertile of mean PaO2, age, shockable rhythm, out of hospital cardiac arrest, duration of cardiopulmonary resuscitation, and ECPR at cardiac catheterization lab were found to be significantly associated with poor neurologic outcomes. Additionally, hypercapnia and extreme hyperoxia were found to be significantly associated with poor neurological outcomes after ECPR. Therefore, maintaining adequate arterial levels of oxygen and carbon dioxide may be important for favorable neurological prognoses in survivors after ECPR.

5.
Micromachines (Basel) ; 13(4)2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35457909

RESUMO

This study investigates the switching characteristics of the silicon oxynitride (SiOxNy)-based bipolar resistive random-access memory (RRAM) devices at different operating ambiances at temperatures ranging from 300 K to 77 K. The operating ambiances (open air or vacuum) and temperature affect the device's performance. The electroforming-free multilevel bipolar Au/Ni/SiOxNy/p+-Si RRAM device (in open-air) becomes bilevel in a vacuum with an on/off ratio >104 and promising data retention properties. The device becomes more resistive with cryogenic temperatures. The experimental results indicate that the presence and absence of moisture (hydrogen and hydroxyl groups) in open air and vacuum, respectively, alter the elemental composition of the amorphous SiOxNy active layer and Ni/SiOxNy interface region. Consequently, this affects the overall device performance. Filament-type resistive switching and trap-controlled space charge limited conduction (SCLC) mechanisms in the bulk SiOxNy layer are confirmed.

6.
Nanoscale ; 14(10): 3738-3747, 2022 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-35187553

RESUMO

This study investigates the temperature-independent switching characteristics of magnesium fluoride (MgFx) based bipolar resistive memory devices at temperatures ranging from 300 K down to 77 K. Filament type resistive switching at the interface of Ti/MgFx and the trap-controlled space charge limited conduction (SCLC) mechanism in the bulk MgFx layer are confirmed. The experimental results indicate that the operating environment and temperature critically control the resistive switching performance by varying the non-stoichiometry of the amorphous MgFx active layer and Ti/MgFx interface region. The gaseous atmosphere (open air or vacuum) affects device performances such as the electroforming process, on-state current, off-state current, on/off ratio, SET/RESET voltage and endurance of resistive-switching memory devices. After electroforming, the device performance is independent of temperature variation. The Ti/MgFx/Pt memory devices show promising data retention for >104 s in a vacuum at room temperature and 77 K with the DC endurance property for more than 150 cycles at 77 K. The devices have great potential for future temperature-independent electronic applications.

7.
Nanomaterials (Basel) ; 12(4)2022 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-35214934

RESUMO

This study investigates switching characteristics of the magnesium fluoride (MgFx)-based bipolar resistive random-access memory (RRAM) devices at different operating ambiances (open-air and vacuum). Operating ambiances alter the elemental composition of the amorphous MgFx active layer and Ti/MgFx interface region, which affects the overall device performance. The experimental results indicate that filament type resistive switching takes place at the interface of Ti/MgFx and trap-controlled space charge limited conduction (SCLC) mechanisms is dominant in both the low and high resistance states in the bulk MgFx layer. RRAM device performances at different operating ambiances are also altered by MgFx active layer treatments (air exposure and annealing). Devices show the better uniformity, stability, and a higher on/off current ratio in vacuum compared to an open-air environment. The Ti/MgFx/Pt memory devices have great potential for future vacuum electronic applications.

8.
Front Neurol ; 12: 700616, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34566844

RESUMO

Objective: To personalize the prognostication of post-stroke outcome using MRI-detected cerebrovascular pathology, we sought to investigate the association between the excessive white matter hyperintensity (WMH) burden unaccounted for by the traditional stroke risk profile of individual patients and their long-term functional outcomes after a stroke. Methods: We included 890 patients who survived after an acute ischemic stroke from the MRI-Genetics Interface Exploration (MRI-GENIE) study, for whom data on vascular risk factors (VRFs), including age, sex, atrial fibrillation, diabetes mellitus, hypertension, coronary artery disease, smoking, prior stroke history, as well as acute stroke severity, 3- to-6-month modified Rankin Scale score (mRS), WMH, and brain volumes, were available. We defined the unaccounted WMH (uWMH) burden via modeling of expected WMH burden based on the VRF profile of each individual patient. The association of uWMH and mRS score was analyzed by linear regression analysis. The odds ratios of patients who achieved full functional independence (mRS < 2) in between trichotomized uWMH burden groups were calculated by pair-wise comparisons. Results: The expected WMH volume was estimated with respect to known VRFs. The uWMH burden was associated with a long-term functional outcome (ß = 0.104, p < 0.01). Excessive uWMH burden significantly reduced the odds of achieving full functional independence after a stroke compared to the low and average uWMH burden [OR = 0.4, 95% CI: (0.25, 0.63), p < 0.01 and OR = 0.61, 95% CI: (0.42, 0.87), p < 0.01, respectively]. Conclusion: The excessive amount of uWMH burden unaccounted for by the traditional VRF profile was associated with worse post-stroke functional outcomes. Further studies are needed to evaluate a lifetime brain injury reflected in WMH unrelated to the VRF profile of a patient as an important factor for stroke recovery and a plausible indicator of brain health.

9.
Micromachines (Basel) ; 12(9)2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34577692

RESUMO

Electroforming-free resistive switching random access memory (RRAM) devices employing magnesium fluoride (MgFx) as the resistive switching layer are reported. The electroforming-free MgFx based RRAM devices exhibit bipolar SET/RESET operational characteristics with an on/off ratio higher than 102 and good data retention of >104 s. The resistive switching mechanism in the Ti/MgFx/Pt devices combines two processes as well as trap-controlled space charge limited conduction (SCLC), which is governed by pre-existing defects of fluoride vacancies in the bulk MgFx layer. In addition, filamentary switching mode at the interface between the MgFx and Ti layers is assisted by O-H group-related defects on the surface of the active layer.

10.
Front Neurosci ; 15: 691244, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34321995

RESUMO

OBJECTIVE: Neuroimaging measurements of brain structural integrity are thought to be surrogates for brain health, but precise assessments require dedicated advanced image acquisitions. By means of quantitatively describing conventional images, radiomic analyses hold potential for evaluating brain health. We sought to: (1) evaluate radiomics to assess brain structural integrity by predicting white matter hyperintensities burdens (WMH) and (2) uncover associations between predictive radiomic features and clinical phenotypes. METHODS: We analyzed a multi-site cohort of 4,163 acute ischemic strokes (AIS) patients with T2-FLAIR MR images with total brain and WMH segmentations. Radiomic features were extracted from normal-appearing brain tissue (brain mask-WMH mask). Radiomics-based prediction of personalized WMH burden was done using ElasticNet linear regression. We built a radiomic signature of WMH with stable selected features predictive of WMH burden and then related this signature to clinical variables using canonical correlation analysis (CCA). RESULTS: Radiomic features were predictive of WMH burden (R 2 = 0.855 ± 0.011). Seven pairs of canonical variates (CV) significantly correlated the radiomics signature of WMH and clinical traits with respective canonical correlations of 0.81, 0.65, 0.42, 0.24, 0.20, 0.15, and 0.15 (FDR-corrected p-values CV 1 - 6 < 0.001, p-value CV 7 = 0.012). The clinical CV1 was mainly influenced by age, CV2 by sex, CV3 by history of smoking and diabetes, CV4 by hypertension, CV5 by atrial fibrillation (AF) and diabetes, CV6 by coronary artery disease (CAD), and CV7 by CAD and diabetes. CONCLUSION: Radiomics extracted from T2-FLAIR images of AIS patients capture microstructural damage of the cerebral parenchyma and correlate with clinical phenotypes, suggesting different radiographical textural abnormalities per cardiovascular risk profile. Further research could evaluate radiomics to predict the progression of WMH and for the follow-up of stroke patients' brain health.

11.
Ann Plast Surg ; 86(1): 89-95, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32568753

RESUMO

BACKGROUND: The arterialized venous flap (AVF) is appropriate as a flap for hand and foot resurfacing meet the aesthetic demands in the same time. However, the inconsistency of survival rate limited its popularization in clinical settings. The purpose of this study was to investigate the role played by the caliber and location of the artery. METHODS: Arterialized venous flaps were designed on the abdomen of New Zealand rabbits, and the animals were randomized into 3 groups and 2 groups in experiment 1 and 2, respectively. In experiment 1, the artery flow was restricted with vascular staplers of different calibers. In experiment 2, the artery was anastomosed with the afferent vein in the center or at the margin of the flap. Blood perfusion state, water content, epidermal metabolite levels, and flap survival status were observed in both experiments. Furthermore, outcomes of 12 patients received AVF to resurface soft tissue defects in the digits, hands, and feet between January 2016 and February 2018 were analyzed. RESULTS: In experiment 1, compared with the control group, groups with restricted artery showed poor results regarding blood perfusion state, water content, epidermal metabolite levels, and flap survival status. In experiment 2, group with the afferent vein in the center of the flap showed better results mentioned previously. All the flaps survived uneventfully in this study. Two flaps partially failed (20% of the flap area) because of insufficient perfusion. Generally, larger caliber and center-located vein helped the survival of AVF. CONCLUSIONS: Experimental findings suggested that increased arterial perfusion and center-located vein are beneficial for the survival of AVF. Clinical series proved the findings previously. The problem of inconsistency of AVF can be partially solved by increasing arterial perfusion and dissecting afferent vein into the center of flap, and still, further studies are needed to shed light on the mechanism behind.


Assuntos
Retalhos Cirúrgicos , Veias , Animais , Artérias/cirurgia , Sobrevivência de Enxerto , Humanos , Perfusão , Coelhos , Procedimentos Cirúrgicos Vasculares , Veias/cirurgia
12.
ACS Biomater Sci Eng ; 5(8): 3935-3943, 2019 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-31723595

RESUMO

Directed collective cell migration governs cell orientation during tissue morphogenesis, wound healing, and tumor metastasis. Unfortunately, current methods for initiating collective cell migration, such as scratching, laser ablation, and stencils, either introduce uncontrolled cell-injury, involve multiple fabrication processes, or have utility limited to cells with strong cell-cell junctions. Using three-dimensional (3D) bioprinted gelatin methacryloyl (GelMA) micropatterns on temperature-responsive poly(N-isopropylacrylamide) (PNIPAm) coated interfaces, we demonstrate that directed injury-free collective cell migration could occur in parallel and perpendicular directions. After seeding cells, we created cell-free spaces between two 3D bioprinted GelMA micropatterns by lowering the temperature of PNIPAm interfaces to promote the cell detachment. Unlike conventional collective cell migration methods initiated by stencils, we observed well-organized cell migration in parallel and perpendicular to 3D bioprinted micropatterns as a function of the distance between 3D bioprinted micropatterns. We further established the utility of controlled collective cell migration for directed functional myotube formation using 3D bioprinted fingerprintlike micropatterns as well as iris musclelike concentric circular patterns. Our platform is unique for myoblast alignment and myotube formation because it does not require anisotropic guidance cues. Together, our findings establish how to achieve controlled collective cell migration, even at the macroscale, for tissue engineering and regeneration.

13.
Sci Total Environ ; 669: 505-511, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30884272

RESUMO

Anthropogenic plutonium (Pu) in the environment is a result of atmospheric nuclear testing during the second half of the 20th century. In this work, we analyzed a 4-meter deep Antarctic Plateau snowpack characterized by a low snow accumulation rate and negligible snow impurities. These sample conditions enabled us to measure the snowpack Pu fallout by applying inductively coupled plasma sector field mass spectrometry to a few mL of snow melt without purification or preconcentration. Pu concentrations in the reconstructed Pu fallout record for the period after 1956 CE increased and decreased in agreement with past atmospheric nuclear testing. Two peaks and two dips associable with historical events were observed, and the highest peak in 1964(±1) CE approximately coincided with the maximum concentration of non-sea-salt sulfate caused by the Mt. Agung eruption in 1963 CE. Enhanced Pu fallout in the 1970s was attributed the geographical proximity of the Southern Hemispheric nuclear test sites. Our results suggest that by improving the instrumental sensitivity and precision, the potential of the Antarctic ice sheet as an archive of Pu fallout can be further explored and utilized for understanding atmospheric dispersion and for dating ice cores.

14.
ACS Appl Bio Mater ; 2(7): 2726-2737, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35030808

RESUMO

Biofouling disrupts the surface functionality and integrity of engineered substrates. A variety of natural materials such as plant leaves and insect wings have evolved sophisticated physical mechanisms capable of preventing biofouling. Over the past decade, several reports have pinpointed nanoscale surface topography as an important regulator of surface adhesion and growth of bacteria. Although artificial nanoengineered features have been used to create bactericidal materials that kill adhered bacteria, functional surfaces capable of synergistically providing antiadhesion and bactericidal properties remain to be developed. Furthermore, fundamental questions pertaining to the need for intrinsic hydrophobicity to achieve bactericidal performance and the role of structure length scale (nano vs micro) are still being explored. Here, we demonstrate highly scalable, cost-effective, and efficient nanoengineered multifunctional surfaces that possess both antiadhesion and bactericidal properties on industrially relevant copper (Cu) and aluminum (Al) substrates. We characterize antiadhesion and bactericidal performance using a combination of scanning electron microscopy (SEM), atomic force microscopy (AFM), live/dead bacterial staining and imaging, as well as solution-phase and Petrifilm measurements of bacterial viability. Our results showed that nanostructures created on both Cu and Al were capable of physical deformation of adhered Escherichia coli bacteria. Bacterial viability measurements on both Cu and Al indicated a complex interaction between the antiadhesion and bactericidal nature of these materials and their surface topography, chemistry, and structure. Increased superhydrophobicity greatly decreased bacterial adhesion while not significantly influencing surface bactericidal performance. Furthermore, we observed that more densely packed nanoscale structures improved antiadhesion properties when compared to larger features, even over extended time scales of up to 24 h. Our data suggests that the superhydrophobic Al substrate possesses superior antiadhesion and bactericidal effects, even over long time courses. The techniques and insights presented here will inform future work on antiadhesion and bactericidal multifunctional surfaces and enable their rational design.

15.
Anal Bioanal Chem ; 410(7): 1911-1921, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29380018

RESUMO

Laser-ablation electrospray ionization (LAESI) imaging mass spectrometry (IMS) is an emerging bioanalytical tool for direct imaging and analysis of biological tissues. Performing ionization in an ambient environment, this technique requires little sample preparation and no additional matrix, and can be performed on natural, uneven surfaces. When combined with optical microscopy, the investigation of biological samples by LAESI allows for spatially resolved compositional analysis. We demonstrate here the applicability of LAESI-IMS for the chemical analysis of thin, desiccated biological samples, specifically Neotibicen pruinosus cicada wings. Positive-ion LAESI-IMS accurate ion-map data was acquired from several wing cells and superimposed onto optical images allowing for compositional comparisons across areas of the wing. Various putative chemical identifications were made indicating the presence of hydrocarbons, lipids/esters, amines/amides, and sulfonated/phosphorylated compounds. With the spatial resolution capability, surprising chemical distribution patterns were observed across the cicada wing, which may assist in correlating trends in surface properties with chemical distribution. Observed ions were either (1) equally dispersed across the wing, (2) more concentrated closer to the body of the insect (proximal end), or (3) more concentrated toward the tip of the wing (distal end). These findings demonstrate LAESI-IMS as a tool for the acquisition of spatially resolved chemical information from fragile, dried insect wings. This LAESI-IMS technique has important implications for the study of functional biomaterials, where understanding the correlation between chemical composition, physical structure, and biological function is critical. Graphical abstract Positive-ion laser-ablation electrospray ionization mass spectrometry coupled with optical imaging provides a powerful tool for the spatially resolved chemical analysis of cicada wings.


Assuntos
Hemípteros/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Asas de Animais/química , Amidas/análise , Aminas/análise , Animais , Ésteres/análise , Hemípteros/anatomia & histologia , Hidrocarbonetos/análise , Terapia a Laser , Lipídeos/análise , Compostos de Fósforo/análise , Sulfonas/análise
16.
Nanoscale ; 9(40): 15314-15322, 2017 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-28820212

RESUMO

A resistive random access memory (RRAM) device with self-rectifying I-V characteristics was fabricated by inserting a silicon nitride (Si3N4) layer between the bottom electrode and solution-processed active material of an iron oxide-graphene oxide (FeOx-GO) hybrid. The fabricated Au/Ni/FeOx-GO/Si3N4/n+-Si memory device exhibited an excellent resistive switching ratio and a rectification ratio higher than 104. In the Au/Ni/FeOx-GO/Si3N4/n+-Si device, resistive switching occurs in both the FeOx-GO and Si3N4 layers separately, resulting in a highly uniform and stable switching performance. The resistive switching from a high resistance state to a low resistance state in the Au/Ni/FeOx-GO/Si3N4/n+-Si device occurs through a trap-assisted tunneling process in the Si3N4 layer, enabled by the FeOx-GO layer which prevents diffusion of the migrating Ni metal into the switching nitride layer. The intrinsic self-rectifying characteristics of our memory devices arise from the asymmetric barriers for electrons tunneling into the traps of the Si3N4 layer which is sandwiched between the top and bottom electrodes having dissimilar work functions. Our study confirmed that integrating a suitable dielectric layer into the conventional RRAM cell is an innovative strategy to simplify the architecture and fabrication process to realize self-rectifying crossbar arrays.

17.
Adv Mater ; 27(27): 4035-40, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-26033288

RESUMO

A 3D printable and highly stretchable tough hydrogel is developed by combining poly(ethylene glycol) and sodium alginate, which synergize to form a hydrogel tougher than natural cartilage. Encapsulated cells maintain high viability over a 7 d culture period and are highly deformed together with the hydrogel. By adding biocompatible nanoclay, the tough hydrogel is 3D printed in various shapes without requiring support material.


Assuntos
Hidrogéis , Impressão Tridimensional , Alicerces Teciduais , Alginatos/química , Materiais Biocompatíveis/química , Cálcio/química , Cátions Bivalentes/química , Sobrevivência Celular/fisiologia , Ácido Glucurônico/química , Células HEK293 , Ácidos Hexurônicos/química , Humanos , Hidrogéis/química , Teste de Materiais , Fenômenos Mecânicos , Células-Tronco Mesenquimais/fisiologia , Nanoestruturas/química , Polietilenoglicóis/química , Alicerces Teciduais/química , Raios Ultravioleta
18.
Lab Chip ; 14(3): 514-521, 2014 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-24310854

RESUMO

We developed a microfluidic flow-control system capable of dynamically generating various flow patterns on demand. The flow-control system is based on novel magnetoactive sponges embedded in microfluidic flow channels. Applying a non-uniform magnetic field compresses the magnetoactive sponge, significantly reducing porosity and hydraulic conductivity. Tuning the applied magnetic field can dynamically vary the flow rate in the microfluidic channel. Pulsatile and physiological flow patterns with frequency between 1 and 3 Hz, flow rates between 0.5 and 10 µL min(-1) and duration over 3 weeks have been achieved. Smooth muscle cells in engineered blood vessels perfused for 7 days aligned perpendicular to the flow direction under pulsatile but not steady flow, similar to the in vivo orientation. Owing to its various advantages over traditional flow-control methods, the new system potentially has important applications in microfluidic-based microphysiological systems to simulate the physiological nature of blood flow.


Assuntos
Técnicas de Cultura de Células/métodos , Técnicas Analíticas Microfluídicas/métodos , Células da Medula Óssea/citologia , Técnicas de Cultura de Células/instrumentação , Células Cultivadas , Humanos , Magnetismo , Técnicas Analíticas Microfluídicas/instrumentação , Miócitos de Músculo Liso/citologia , Miócitos de Músculo Liso/metabolismo , Óxido Nítrico/metabolismo , Porosidade , Fluxo Pulsátil , Engenharia Tecidual
19.
J Pediatr Surg ; 48(8): 1722-6, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23932612

RESUMO

BACKGROUND/PURPOSE: A silicone central venous catheter (CVC) is usually inserted using a percutaneous technique under general anesthesia. However, there are numerous reports on the postoperative adverse effects of general anesthesia in neonates. The aim of this study is to investigate the feasibility of open surgical cutdown (OSC) for central venous access without general anesthesia. METHODS: The medical records of patients who underwent OSC at bedside under sedation and local anesthesia were reviewed. Chloral hydrate (100mg/kg) was given orally for the induction of moderate to deep sedation 15 minutes before OSC; then the operative field was infiltrated with 1% lidocaine. When adequate sedation was not achieved, a bolus of phenobarbital (20mg/kg) was given intravenously. RESULTS: Thirteen Broviac lines were inserted into 12 patients. At insertion, the median gestational age was 29 weeks, birth weight was 1,140 g and age was 33 days. No patients required invasive ventilator care; 7 patients received nasal non-invasive ventilator care. Neither intubation nor inotropics were required during the intra- or postoperative period and no perioperative surgical complications occurred. The median catheter duration was 19.5 days. CONCLUSION: OSC at bedside for CVC insertion, using adequate sedation and local anesthesia, is a feasible procedure in neonates.


Assuntos
Anestesia Local/métodos , Cateterismo Venoso Central/métodos , Sedação Profunda/métodos , Doenças do Prematuro/tratamento farmacológico , Veias Jugulares/cirurgia , Sistemas Automatizados de Assistência Junto ao Leito , Venostomia/métodos , Administração Oral , Anestésicos Locais/administração & dosagem , Hidrato de Cloral/administração & dosagem , Estudos de Viabilidade , Cardiopatias Congênitas/complicações , Humanos , Hipnóticos e Sedativos/administração & dosagem , Recém-Nascido de Baixo Peso , Recém-Nascido , Recém-Nascido Prematuro , Injeções Intravenosas , Lidocaína/administração & dosagem , Fenobarbital/administração & dosagem , Sepse/tratamento farmacológico
20.
J Pediatr Surg ; 48(2): 429-31, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23414879

RESUMO

The diagnosis of a thyroglossal duct cyst is often apparent when it presents with typical findings. We report a case of a 6 year-old girl with a low-lying thyroglossal duct cyst presenting with recurrent lateral cervical discharge without palpable mass, thus mimicking a second branchial cleft fistula. CT scan differentiated the lesion from a second branchial cleft fistula, and a standard Sistrunk procedure cured the lesion. In patients who show lateral cervical discharge without definite mass, therefore mimicking a second branchial cleft fistula, a low-lying thyroglossal duct cyst should be considered.


Assuntos
Região Branquial/anormalidades , Fístula/diagnóstico , Cisto Tireoglosso/complicações , Cisto Tireoglosso/diagnóstico , Criança , Diagnóstico Diferencial , Feminino , Humanos , Cisto Tireoglosso/patologia
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