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1.
Food Chem ; 324: 126889, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32353659

RESUMO

Pesticides have been extensively applied worldwide to protect crops from worms and insects; however, the continuous use of pesticides affects ecosystems, agricultural product safety, nontarget organisms, and human health. In this paper, we report a highly sensitive biosensor for the determination of pesticides based on tin sulfide (SnS2) and chitosan (CHIT) nanocomposites decorated with a unique British housefly acetylcholinesterase (AChE). The hydrothermally synthesized nano-SnS2 mixed with chitosan solution (CHIT-SnS2) was drop-casted onto a glassy carbon electrode (GCE). Subsequently, the British housefly AChE was immobilized on the CHIT/SnS2-coated GCE that was then employed for pesticide detection. The developed biosensor showed an ultra-high sensitivity and wide linear detection range from 0.02 nM to 20000 nM with a detection limit of 0.02 nM for the detection of chlorpyrifos as the model pesticide. Furthermore, the AChE/CHIT-SnS2/GCE exhibited acceptable storage stability, good reproducibility, and selectivity.

2.
MAGMA ; 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32297164

RESUMO

OBJECTIVES: This study aims to evaluate the reproducibility of measures of plaque morphology in serially acquired black-blood MRI of untreated atherosclerotic femoral arteries. MATERIALS AND METHODS: MR studies was obtained from 42 timepoints, on 12 patients with known femoral artery atherosclerosis. Images with a 3D isotropic FLASH with DANTE-prepared black blood contrast (DASH) at a 3-T scanner were acquired at baseline, within 1 week, and at 1 month. Six of the patients were scanned additionally at 6 months. Inter-scan and inter-observer variations of arterial area/volume measurements were evaluated. RESULTS: Measurement of vessel area, lumen area, wall area and wall volume showed inter-scan intraclass correlation coefficients (ICC) ranging from 0.92 to 0.97 for 3 scans, 0.91-0.97 for 4 scans, and inter-observer ICCs of 0.89-0.96. Among 3 scans, the coefficients of variance (CV) for the vessel area, lumen area, wall area and wall volume were 4.1%, 6.5%, 7.5%, and 4.4%. CVs among 4 scans ranged from 4.4% to 7.9%, and interobserver CVs ranged from 6.1% to 11.8% for the different area/volume measurements. CONCLUSION: DASH MRI is useful for quantifying atherosclerotic vessel area and volume of femoral arteries with low variability among serial repeated scans and between observers.

3.
Med Biol Eng Comput ; 58(4): 871-885, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32077011

RESUMO

Master-slave endovascular interventional surgery (EIS) robots have brought revolutionary advantages to traditional EIS, such as avoiding X-ray radiation to the surgeon and improving surgical precision and safety. However, the master controllers of most of the current EIS robots always lead to bad human-machine interaction, because of the difference in nature between the rigid operating handle and the flexible medical catheter used in EIS. In this paper, a noncontact detection method is proposed, and a novel master controller is developed to realize real-time detection of surgeon's operation without interference to the surgeon. A medical catheter is used as the operating handle. It is enabled by using FAST corner detection algorithm and optical flow algorithm to track the corner points of the continuous markers on a designed sensing pipe. A mathematical model is established to calculate the axial and rotational motion of the sensing pipe according to the moving distance of the corner points in image coordinates. A master-slave EIS robot system is constructed by integrating the proposed master controller and a developed slave robot. Surgical task performance evaluation in an endovascular evaluator (EVE) is conducted, and the results indicate that the proposed detection method breaks through the axial measuring range limitation of the previous marker-based detection method. In addition, the rotational detection error is reduced by 92.5% compared with the previous laser-based detection method. The results also demonstrate the capability and efficiency of the proposed master controller to control the slave robot for surgical task implementation. Graphical abstract A novel master controller is developed to realize real-time noncontact detection of surgeon's operation without interference to the surgeon. The master controller is used to remotely control the slave robot to implement certain surgical tasks.

4.
Magn Reson Imaging ; 66: 199-207, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31493474

RESUMO

PURPOSE: To theoretically compare the MR angiography (MRA) contrast mechanism of Time of Flight (TOF) and Simultaneous Non-contrast Angiography and intraPlaque hemorrhage (SNAP) for intracranial artery imaging with in-vivo validation. METHODS: The contrast ratio (CR) of SNAP and TOF was simulated under different blood velocities and travel distance that the blood had flown through. The CR and the slope of CR with respect to blood velocity of SNAP and TOF were compared in theoretical simulation. Two healthy subjects (a 60 years old female and a 29 years old male) were imaged on a 3 T MR scanner with SNAP, TOF and phase contrast (PC) images as the validation set. The measured CR from the images in validation set was compared with the theoretically simulated CR by Person's correlation coefficient. The ratio of CR difference to velocity difference in the validation set was compared between TOF and SNAP with Student's t-test. Thirty patients (21 males, age: 48 ±â€¯13.8 years) with carotid artery atherosclerotic plaque were imaged with both TOF and SNAP as the comparison test. Between TOF and SNAP, the CR and total artery length were compared with Student's t-test, and the prevalence of stenosis was compared with Cohen's kappa in comparison test. RESULTS: The theoretically simulated CR was significantly correlated with in-vivo measured CR from the validation set for TOF (p < 0.001) and SNAP (p < 0.001). The simulation revealed that the CR of SNAP was higher than that of TOF when the blood velocity and travel distance were within the range to have effective MRA contrast. Similarly, the in-vivo comparison test showed that SNAP had higher CR (p < 0.001 for all tested intracranial arteries) and longer total artery length (1.4 ±â€¯0.4 m vs 1.2 ±â€¯0.2 m, p < 0.001) than TOF. The stenosis detection performance was similar between TOF and SNAP (Cohen's kappa 0.72; 95% confidence interval: 0.51-0.93). Moreover, compared with TOF, SNAP showed higher slope of CR with respect to velocity in simulation (0.06 ±â€¯0.02 s/cm vs 0.02 ±â€¯0.05 s/cm, p < 0.001), and higher ratio of CR difference to velocity difference in validation test (0.47 ±â€¯0.38 s/cm vs 0.19 ±â€¯0.38 s/cm, p = 0.001). CONCLUSIONS: Compared with TOF, the SNAP shows better performance to visualize distal intracranial artery and worse performance to visualize ICA, and is more sensitive to blood velocity.

5.
J Nanosci Nanotechnol ; 20(3): 1790-1798, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31492344

RESUMO

Tungsten oxide microflowers (WO3 MFs) were fabricated by a simple hydrothermal process through adjusting the pH of the solution by HCl. These MFs possess the outer diameters of about 2 µm and are composed of numerous nanoplates with the average pore size of 10.9 nm. Chemiresistive activity of as-fabricated WO3 MFs sensor was attempted towards oxidizing and reducing target gases, revealing a superior selectivity to NO2 with a maximum response of 22.95 (2 ppm NO2) @105 °C compared to other target gases. One of the key features of as-fabricatedWO3 MFs sensor is the lower detection limit of 125 ppb and operating temperature of 105 °C to NO2 with better reproducibility, signifying commercial prospective of the developed sensor materials. Finally, the gas sensing mechanism of WO3 MFs sensor has been proposed.

6.
Eur Radiol ; 30(1): 301-307, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31218429

RESUMO

PURPOSE: To evaluate and compare wall enhancement patterns in saccular and fusiform intracranial aneurysms using high-resolution black-blood MRI at 7 T. METHODS: Thirty-one patients with 32 unruptured intracranial aneurysms (21 saccular and 11 fusiform) underwent 7-T black-blood MRI. Aneurysm wall enhancement (AWE) was categorized as follows: no wall enhancement (NWE), focal wall enhancement (FWE), and uniform wall enhancement (UWE). The degree of enhancement was scored as follows: 0 (no enhancement), 1 (signal intensity (SI) of the aneurysm wall less than that of the pituitary infundibulum), and 2 (equal to that of the pituitary infundibulum). The chi-squared test was used to compare the AWE pattern and degree between saccular and fusiform aneurysms. RESULTS: In saccular aneurysms, 12/21 (57%) enhanced. Of these, 9 showed FWE (5 grade 1 and 4 grade 2), and 3 showed UWE (2 grade 1 and 1 grade 2). In fusiform aneurysms, 11/11 (100%) enhanced. Of these, 1 showed FWE and 10 showed UWE. All fusiform aneurysms had grade-2 enhancement. Fusiform aneurysms had more extensive and higher SI AWE than saccular aneurysms (p < 0.01) despite having a similar size (6.9 ± 3.0 mm vs. 8.0 ± 2.9, p = 0.23). For saccular aneurysm, larger aneurysm size was correlated with higher degree of enhancement with Pearson's r = 0.64 (p = 0.002). CONCLUSION: Intracranial fusiform aneurysms had enhancement of higher SI and that covered a more extensive area than saccular aneurysms, which might indicate differences in vessel wall pathology. KEY POINTS: • Intracranial aneurysm wall enhancement can be reliably characterized by 7-T black-blood MRI. • AWE in intracranial fusiform aneurysms presents over a larger surface area and with greater signal intensity as compared with that in saccular aneurysms, which might indicate differences in pathology. • Stronger signal intensity of AWE correlates with the aneurysm size in saccular aneurysms.


Assuntos
Aneurisma Intracraniano/diagnóstico por imagem , Imagem por Ressonância Magnética/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Aneurisma Intracraniano/patologia , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Adulto Jovem
7.
Artigo em Inglês | MEDLINE | ID: mdl-31689186

RESUMO

Timely and accurate auxiliary diagnosis of intracranial aneurysm can help radiologist make treatment plans quickly, saving lives and cutting costs at the same time. At present Digital Subtraction Angiography (DSA) is the gold standard for the diagnosis of intracranial aneurysm, but as radiologists interpret those imaging sequences frame by frame, misdiagnosis might occur. The utilization of computer-assisted diagnosis (CAD) can ease the burdens of radiologists and improve the detection accuracy of aneurysms. In this paper, a deep learning method is applied to detect the intracranial aneurysm in 3D Rotational Angiography (3D-RA) based on a spatial information fusion (SIF) method, and in stead of 3D vascular model, 2D image sequences are used. Given the intracranial aneurysm and vascular overlap having similar feature in the most time, rather than focusing on distinguishing them in one frame, the morphological differences between frames are considered as major feature. In the training data, consecutive frames of every imaging time series are extracted and concatenated in a specific way, so that the spatial contextual information could be embedded into a single twodimensional image. This method enables the time series with obvious correlation between frames be directly trained on 2D convolutional neural network (CNN), instead of 3D-CNN with huge computational cost. Finally, we got an accuracy of 98.89%, with sensitivity and specificity of 99.38% and 98.19% respectively, which proves the feasibility and availability of the SIF feature.

8.
Med Biol Eng Comput ; 57(9): 1875-1887, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31222531

RESUMO

Performance of robot-assisted endovascular surgery (ES) remains highly dependent on an individual surgeon's skills, due to common adoption of master-slave robotic structure. Surgeons' skill modeling and unstructured surgical state perception pose prohibitive challenges for an autonomous ES robot. In this paper, a novel convolutional neural network (CNN)-based framework is proposed to address these challenges for navigation of an ES robot based on surgeons' skill learning. An operating action probability estimator is proposed by integrating a two-dimensional CNN, with which the features of a surgical state image are extracted and then directly mapped to the action probability. A one-dimensional CNN with multi-input is developed to recognize the guide wire operating force condition. An eye-hand collaborative servoing algorithm is proposed to combine the outputs of these two networks and to control the robot under a closed-loop architecture. A real-world ES robot is employed for data collection and task performance evaluation in laboratory condition. Compared with the state of the art, the CNN-based method shows its capability of adapting to different situations and achieves similar success rate and average operating time. Robotic operation performs similar operating trajectory and maintains similar level of operating force with manual operation. The CNN-based method can be easily extended to many other surgical robots. Graphical abstract A surgeon's guide wire operating skills in endovascular surgery (ES) is learned by the proposed CNN-based method. Then, the learned model is used for autonomous control of a ES robot with surgical state input (images and operating force).


Assuntos
Procedimentos Endovasculares/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Algoritmos , Procedimentos Endovasculares/instrumentação , Desenho de Equipamento , Mãos/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Procedimentos Cirúrgicos Robóticos/instrumentação
9.
Nanoscale Res Lett ; 14(1): 189, 2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31165287

RESUMO

Cortisol, a steroid hormone, is secreted by the hypothalamic-pituitary-adrenal system. It is a well-known biomarker of psychological stress and is hence known as the "stress hormone." If cortisol overexpression is prolonged and repeated, dysfunction in the regulation of cortisol eventually occurs. Therefore, a rapid point-of-care assay to detect cortisol is needed. Salivary cortisol electrochemical analysis is a non-invasive method that is potentially useful in enabling rapid measurement of cortisol levels. In this study, multilayer films containing two-dimensional tin disulfide nanoflakes, cortisol antibody (C-Mab), and bovine serum albumin (BSA) were prepared on glassy carbon electrodes (GCE) as BSA/C-Mab/SnS2/GCE, and characterized using electrochemical impedance spectroscopy and cyclic voltammetry. Electrochemical responses of the biosensor as a function of cortisol concentrations were determined using cyclic voltammetry and differential pulse voltammetry. This cortisol biosensor exhibited a detection range from 100 pM to 100 µM, a detection limit of 100 pM, and a sensitivity of 0.0103 mA/Mcm2 (R2 = 0.9979). Finally, cortisol concentrations in authentic saliva samples obtained using the developed electrochemical system correlated well with results obtained using enzyme-linked immunosorbent assays. This biosensor was successfully prepared and used for the electrochemical detection of salivary cortisol over physiological ranges, based on the specificity of antibody-antigen interactions.

10.
J Nanosci Nanotechnol ; 19(12): 8135-8142, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31196336

RESUMO

Precisely controlled dimensions of heterostructured ZnO nanorod arrays were grown on micropatterned Au films supported by Si substrate using chemical vapor deposition (CVD). The field emission properties were attributed to pointed nanorods, thickness of catalyst, preferential growth, density, morphology of ZnO and Molybdenum (Mo) decorated ZnO nanorod arrays (Mo/ZnO). The selective restrained heterostructure approach resulted in excellent control over periodicity, location and density of ZnO nanorod arrays. Overall, field emission properties of bare ZnO nanorod arrays showed a low turn-on field of ~4.7 V/µm and a high field enhancement factor (ß) ~1686 to 7.3 V/µm and (ß) ~807 for Mo/ZnO. It was also found that the field emission properties were significantly influenced by densely decorated Mo nanoparticles on as-grown ZnO nanorod arrays.

11.
Atherosclerosis ; 287: 112-121, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31254918

RESUMO

BACKGROUND AND AIMS: Intracranial atherosclerotic plaque is associated with ischemic strokes without substantial stenosis, and needs better characterization. We aim to investigate the clinical significance of intracranial plaque without substantial stenosis by high resolution vessel wall MRI (vwMRI) through a systematic review of existing studies. METHODS: Studies investigating intracranial arterial atherosclerotic plaques without substantial stenosis in acute ischemic stroke patients using vwMRI were systematically identified by searching the PubMed and Medline database and article reference lists. Study characteristics were recorded, the methodological quality of eligible studies was assessed, relevant clinical data were extracted, and collective data was analyzed. RESULTS: Twenty-one studies were identified as eligible. 463 patients were included without stenosis of the intracranial arteries, and 651 patients were included with stenosis <50%. The prevalence of intracranial plaque revealed by vwMRI among acute/subacute ischemic stroke patients with non-stenotic Magnetic Resonance Angiography (MRA) was 50.6% (95% confidence interval (CI), 46.1%-55.1%). The prevalence of <50% MRA stenotic culprit plaque among acute/subacute ischemic stroke patients with a clinical diagnosis of intracranial atherosclerosis was 51.2% (95% CI, 38.4%-64.0%). Plaques features, including wall enhancement, positive remodeling, intraplaque hemorrhage, plaque location and eccentricity, were associated with acute stroke, progressive motor deficits and unfavorable overall functional outcomes. CONCLUSIONS: Intracranial high-risk plaque with zero or mild degree of stenosis is more prevalent than previously acknowledged, and is associated with ischemic stroke and unfavorable outcome. VwMRI can identify the high-risk plaque features, which may act as a promising tool to better risk stratify these patients.

12.
World Neurosurg ; 127: e30-e38, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30790737

RESUMO

OBJECTIVE: A prospective trial was conducted to investigate the platelet function and association between thrombelastographic (TEG) parameters and embolic or hemorrhagic complications in patients with intracranial aneurysm undergoing stent treatment. METHODS: Between September 2013 and June 2016, we prospectively recruited patients with intracranial aneurysm who were treated with stent-assisted coiling. TEG parameters were used to assess the platelet function before stenting procedures. The primary study end point was the onset of ischemic stroke, transient ischemic attack, or silent ischemic events in the territory of the stented artery within 6 months after the procedure. The secondary end point was assessed by bleeding events. RESULTS: Four hundred and thirty-one patients with 453 intracranial aneurysms were enrolled. A total of 519 neurovascular stents were implanted. During the follow-up, a total of 70 primary end points (16.2%) and 59 secondary end points (13.7%) were detected. Thromboembolic complications such as symptomatic and slient ischemic complications were more frequently observed in patients with large aneurysms (>10 mm, P = 0.01), lower adenosine diphosphate (ADP) inhibition rate (P < 0.0001), and higher ADP-induced platelet-fibrin clot strength (maximum amplitude of adenosine diphosphate [MA-ADP]) (P < 0.0001). Besides, based on multivariate analysis, a higher ADP inhibition ratio was identified as a significant independent predictor of subsequent bleeding events (P < 0.0001). According to the receiver operating characteristic curve analysis, the safe range of the ADP inhibition ratio and MA-ADP of the TEG analysis were identified as 29.45%-55.4% and <46.15, respectively. CONCLUSIONS: The ADP inhibition ratio and MA-ADP of TEG analysis were associated with subsequent cerebral ischemic events and intracranial or extracranial bleeding events in patients with intracranial aneurysm after stent treatment.


Assuntos
Isquemia Encefálica/etiologia , Embolização Terapêutica , Procedimentos Endovasculares , Aneurisma Intracraniano/complicações , Stents , Tromboelastografia , Difosfato de Adenosina/farmacologia , Adolescente , Adulto , Idoso , Biomarcadores , Terapia Combinada , Comorbidade , Feminino , Humanos , Aneurisma Intracraniano/sangue , Aneurisma Intracraniano/cirurgia , Aneurisma Intracraniano/terapia , Hemorragias Intracranianas/etiologia , Ataque Isquêmico Transitório/etiologia , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Agregação Plaquetária/efeitos dos fármacos , Testes de Função Plaquetária , Estudos Prospectivos , Fatores de Risco , Adulto Jovem
13.
Nanoscale Res Lett ; 14(1): 40, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30706287

RESUMO

Vertical GaN Schottky barrier diodes (SBDs) were fabricated on Ge-doped free-standing GaN substrates. The crystal quality of the SBDs was characterized by cathode luminescence measurement, and the dislocation density was determined to be ~ 1.3 × 106 cm- 2. With the electrical performance measurements conducted, the SBDs show a low turn-on voltage Von (0.70~0.78 V) and high current Ion/Ioff ratio (9.9 × 107~1.3 × 1010). The reverse recovery characteristics were investigated. The reverse recovery time was obtained to be 15.8, 16.2, 18.1, 21.22, and 24.5 ns for the 100-, 200-, 300-, 400-, and 500-µm-diameter SBDs, respectively. Meanwhile, the reverse recovery time and reverse recovery charge both show a significant positive correlation with the electrode area.

14.
J Magn Reson Imaging ; 50(3): 994-1001, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30694008

RESUMO

BACKGROUND: Intraluminal thrombus (ILT) signal intensity on MRI has been studied as a potential marker of abdominal aortic aneurysm (AAA) progression. PURPOSE: 1) To characterize the relationship between ILT signal intensity and AAA diameter; 2) to evaluate ILT change over time; and 3) to assess the relationship between ILT features and AAA growth. STUDY TYPE: Prospective. SUBJECTS: Eighty AAA patients were imaged, and a subset (n = 41) were followed with repeated MRI for 16 ± 9 months. FIELD STRENGTH/SEQUENCE: 3D black-blood fast-spin-echo sequence at 3 T. ASSESSMENT: ILT was designated as "bright" if the signal was greater than 1.2 times that of adjacent psoas muscle. AAAs were divided into three groups based on ILT: Type 1: bright ILT; Type 2: isointense ILT; Type 3: no ILT. During follow-up, an active ILT change was defined as new ILT formation or an increase in ILT signal intensity to bright; stable ILT was defined as no change in ILT type or ILT became isointense from bright previously. STATISTICAL TESTS: Shapiro-Wilk test; Mann-Whitney U-test; Fisher's exact test; Kruskal-Wallis test; Spearman's r; intraclass correlation coefficient (ICC), Cohen's kappa. RESULTS: AAAs with Type 1 ILT were larger than those with Types 2 and 3 ILT (5.1 ± 1.1 cm, 4.4 ± 0.9 cm, 4.2 ± 0.8 cm, P = 0.008). The growth rate of AAAs with Type 1 ILT was significantly greater than that of AAAs with Types 2 and 3 ILT (2.6 ± 2.5, 0.6 ± 1.3, 1.5 ± 0.6 mm/year, P = 0.01). During follow-up, AAAs with active ILT changes had a 3-fold increased growth rate compared with AAAs with stable ILT (3.6 ± 3.0 mm/year vs. 1.2 ± 1.5 mm/year, P = 0.008). DATA CONCLUSION: AAAs with bright ILT are larger in diameter and grow faster. Active ILT change is associated with faster AAA growth. Black-blood MRI can characterize ILT features and monitor their change over time, which may provide new insights into AAA risk assessment. LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2019;50:994-1001.

15.
Nanoscale Res Lett ; 13(1): 405, 2018 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-30560382

RESUMO

The energy band alignment at the multilayer-MoS2/ZrO2 interface and the effects of CHF3 plasma treatment on the band offset were explored using x-ray photoelectron spectroscopy. The valence band offset (VBO) and conduction band offset (CBO) for the MoS2 /ZrO2 sample is about 1.87 eV and 2.49 eV, respectively. While the VBO was enlarged by about 0.75 eV for the sample with CHF3 plasma treatment, which is attributed to the up-shift of Zr 3d core level. The calculation results demonstrated that F atoms have strong interactions with Zr atoms, and the valence band energy shift for the d-orbital of Zr atoms is about 0.76 eV, in consistent with the experimental result. This interesting finding encourages the application of ZrO2 as gate materials in MoS2-based electronic devices and provides a promising way to adjust the band alignment.

16.
Biomed Microdevices ; 20(2): 34, 2018 04 07.
Artigo em Inglês | MEDLINE | ID: mdl-29627886

RESUMO

Remote-controlled vascular interventional robots (RVIRs) are being developed to increase the accuracy of surgical operations and reduce the number of occupational risks sustained by intervening physicians, such as radiation exposure and chronic neck/back pain. However, complex control of the RVIRs improves the doctor's operation difficulty and reduces the operation efficiency. Furthermore, incomplete sterilization of the RVIRs will increase the risk of infection, or even cause medical accidents. In this study, we introduced a novel method that provides higher operation efficiency than a previous prototype and allows for complete robot sterilization. A prototype was fabricated and validated through laboratory setting experiments and an in-human experiment. The results illustrated that the proposed RVIR has better performance compared with the previous prototype, and preliminarily demonstrated that the proposed RVIR has good safety and reliability and can be used in clinical surgeries.


Assuntos
Procedimentos Cirúrgicos Robóticos/instrumentação , Procedimentos Cirúrgicos Vasculares/instrumentação , Desenho de Equipamento , Humanos , Fatores de Tempo
17.
Adv Mater ; 29(24)2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28401603

RESUMO

Black phosphorus carbide (b-PC) is a new family of layered semiconducting material that has recently been predicted to have the lightest electrons and holes among all known 2D semiconductors, yielding a p-type mobility (≈105 cm2 V-1 s-1 ) at room temperature that is approximately five times larger than the maximum value in black phosphorus. Here, a high-performance composite few-layer b-PC field-effect transistor fabricated via a novel carbon doping technique which achieved a high hole mobility of 1995 cm2 V-1 s-1 at room temperature is reported. The absorption spectrum of this material covers an electromagnetic spectrum in the infrared regime not served by black phosphorus and is useful for range finding applications as the earth atmosphere has good transparency in this spectral range. Additionally, a low contact resistance of 289 Ω µm is achieved using a nickel phosphide alloy contact with an edge contacted interface via sputtering and thermal treatment.

18.
Opt Express ; 25(8): A253-A263, 2017 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-28437893

RESUMO

As it already made huge effect in the commercialization of silicon and other photovoltaics, interface engineering is dispensable in the current and future evolution of hybrid perovskite solar cells (PSCs) techniques. In order to solve carriers' recombination and detention at the cathode side of planar PSCs, in this work, Ruthenium acetylacetonate (RuAcac) was successfully adopted as a reliable and stable cathode interfacial layer (CIL) to improve the inverted planar PSCs. The power conversion efficiency of the optimal devices was enhanced from 12.74% for the control device without RuAcac, to 17.15% for the RuAcac based devices, with an open circuit voltage of 1.077 V, a short circuit current density of 21.28 mA/cm2, and fill factor of 74.7% correspondingly. A series of photon-physics and microscopy protocols, including EQE, UPS, XPS, PL and SKPM, were used to discover the function of RuAcac CIL. Those results confirms an identical conclusion that RuAcac enables the formation of quasi-ohmic contact at the cathode side by eliminating the energy level barrier between the LUMO of PCBM and Fermi level of silver electrode. The low temperature and facile processed Ruthenium acetylacetonate in this work definitely offer us a robust interface-engineering way for the perovskite solar cells and also their commercialization.

19.
Sci Rep ; 7: 40669, 2017 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-28084434

RESUMO

Two-dimensional layered semiconductors such as molybdenum disulfide (MoS2) at the quantum limit are promising material for nanoelectronics and optoelectronics applications. Understanding the interface properties between the atomically thin MoS2 channel and gate dielectric is fundamentally important for enhancing the carrier transport properties. Here, we investigate the frequency dispersion mechanism in a metal-oxide-semiconductor capacitor (MOSCAP) with a monolayer MoS2 and an ultra-thin HfO2 high-k gate dielectric. We show that the existence of sulfur vacancies at the MoS2-HfO2 interface is responsible for the generation of interface states with a density (Dit) reaching ~7.03 × 1011 cm-2 eV-1. This is evidenced by a deficit S:Mo ratio of ~1.96 using X-ray photoelectron spectroscopy (XPS) analysis, which deviates from its ideal stoichiometric value. First-principles calculations within the density-functional theory framework further confirms the presence of trap states due to sulfur deficiency, which exist within the MoS2 bandgap. This corroborates to a voltage-dependent frequency dispersion of ~11.5% at weak accumulation which decreases monotonically to ~9.0% at strong accumulation as the Fermi level moves away from the mid-gap trap states. Further reduction in Dit could be achieved by thermally diffusing S atoms to the MoS2-HfO2 interface to annihilate the vacancies. This work provides an insight into the interface properties for enabling the development of MoS2 devices with carrier transport enhancement.

20.
Sci Rep ; 6: 26609, 2016 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-27222074

RESUMO

Black phosphorus (BP) is the most stable allotrope of phosphorus which exhibits strong in-plane anisotropic charge transport. Discovering its interface properties between BP and high-k gate dielectric is fundamentally important for enhancing the carrier mobility and electrostatics control. Here, we investigate the impact of interface engineering on the transport properties of BP transistors with an ultra-thin hafnium-dioxide (HfO2) gate dielectric of ~3.4 nm. A high hole mobility of ~536 cm(2)V(-1)s(-1) coupled with a near ideal subthreshold swing (SS) of ~66 mV/dec were simultaneously achieved at room temperature by improving the BP/HfO2 interface quality through thermal treatment. This is attributed to the passivation of phosphorus dangling bonds by hafnium (Hf) adatoms which produces a more chemically stable interface, as evidenced by the significant reduction in interface states density. Additionally, we found that an excessively high thermal treatment temperature (beyond 200 °C) could detrimentally modify the BP crystal structure, which results in channel resistance and mobility degradation due to charge-impurities scattering and lattice displacement. This study contributes to an insight for the development of high performance BP-based transistors through interface engineering.

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