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1.
Adv Mater ; : e2401724, 2024 Apr 04.
Article in English | MEDLINE | ID: mdl-38575151

ABSTRACT

Simultaneously achieving a high photoluminescence quantum yield (PLQY), ultrashort exciton lifetime, and suppressed concentration quenching in thermally activated delayed fluorescence (TADF) materials is desirable yet challenging. Here, a novel acceptor-donor-acceptor type TADF emitter, namely, 2BO-sQA, wherein two oxygen-bridged triarylboron (BO) acceptors are arranged with cofacial alignment and positioned nearly orthogonal to the rigid dispirofluorene-quinolinoacridine (sQA) donor is reported. This molecular design enables the compound to achieve highly efficient (PLQYs up to 99%) and short-lived (nanosecond-scale) blue TADF with effectively suppressed concentration quenching in films. Consequently, the doped organic light-emitting diodes (OLEDs) base on 2BO-sQA achieve exceptional electroluminescence performance across a broad range of doping concentrations, maintaining maximum external quantum efficiencies (EQEs) at over 30% for doping concentrations ranging from 10 to 70 wt%. Remarkably, the nondoped blue OLED achieves a record-high maximum EQE of 26.6% with a small efficiency roll-off of 14.0% at 1000 candelas per square meter. By using 2BO-sQA as the sensitizer for the multiresonance TADF emitter ν-DABNA, TADF-sensitized fluorescence OLEDs achieve high-efficiency deep-blue emission. These results demonstrate the feasibility of this molecular design in developing TADF emitters with high efficiency, ultrashort exciton lifetime, and minimal concentration quenching.

2.
World Neurosurg ; 176: 272, 2023 08.
Article in English | MEDLINE | ID: mdl-37550939

ABSTRACT

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. It includes data and figures from patients that were cared for by Dr. Malek at the Cerebrovascular Hemodynamics laboratory in the Department of Neurosurgery at Tufts Medical Center. The Editor-in-Chief has been informed by Tufts Medical Center that the authors of the paper did not have clinical privileges for these patients and played no clinical role in their care.

3.
World Neurosurg ; 176: 273, 2023 08.
Article in English | MEDLINE | ID: mdl-37550940

ABSTRACT

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. It includes data and figures from patients that were cared for by Dr. Malek at the Cerebrovascular Hemodynamics laboratory in the Department of Neurosurgery at Tufts Medical Center. The Editor-in-Chief has been informed by Tufts Medical Center that the authors of the paper did not have clinical privileges for these patients and played no clinical role in their care.

4.
Adv Sci (Weinh) ; 10(23): e2300808, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37279379

ABSTRACT

The development of orange-red/red thermally activated delayed fluorescence (TADF) materials with both high emission efficiencies and short lifetimes is highly desirable for electroluminescence (EL) applications, but remains a formidable challenge owing to the strict molecular design principles. Herein, two new orange-red/red TADF emitters, namely AC-PCNCF3 and TAC-PCNCF3, composed of pyridine-3,5-dicarbonitrile-derived electron-acceptor (PCNCF3) and acridine electron-donors (AC/TAC) are developed. These emitters in doped films exhibit excellent photophysical properties, including high photoluminescence quantum yields of up to 0.91, tiny singlet-triplet energy gaps of 0.01 eV, and ultrashort TADF lifetimes of less than 1 µs. The TADF-organic light-emitting diodes employing the AC-PCNCF3 as emitter achieve orange-red and red EL with high external quantum efficiencies of up to 25.0% and nearly 20% at doping concentrations of 5 and 40 wt%, respectively, both accompanied by well-suppressed efficiency roll-offs. This work provides an efficient molecular design strategy for developing high-performance red TADF materials.

5.
Sci Rep ; 13(1): 9429, 2023 06 09.
Article in English | MEDLINE | ID: mdl-37296199

ABSTRACT

The aim of this study was to identify the exact origin of force sense and identify whether it arises centrally or peripherally. The present study was designed to analyze the effects of short-term fatigue on pinch force sense and the duration of these effects. During the fatigue protocol, twenty (10 men and 10 women; Mage = 22.0 years old) young Chinese participants were asked to squeeze maximally until the pinch grip force decreased to 50% of its maximal due to fatigue. Participants were instructed to produce the target force (10% of maximal voluntary isometric contraction) using the same hand before and after fatigue (immediately, 10, 30, 60, 180, 300 s). The results showed significantly higher absolute error immediately after fatigue (1.22 ± 1.06 N) than before fatigue (0.68 ± 0.34 N), and 60 s (0.76 ± 0.69 N), 180 s (0.67 ± 0.42 N), and 300 s (0.75 ± 0.37 N) after fatigue (all P < 0.05) but with no effect on the variable error (P > 0.05). It was also revealed that there was a significant overestimate of the constant error values before (0.32 ± 0.61 N) and immediately after fatigue (0.80 ± 1.38 N, all P < 0.05), while no significant overestimation or underestimation exceeded 300 s after fatigue (P > 0.05). Our study results revealed that short-term fatigue resulted in a significant decrease in force sense accuracy, but it did not affect force sense consistently; however, force sense accuracy recovered to a certain extent within 10 s and 30 s, whereas it recovered fully within 60 s, and force sense directivity improvement exceeded 300 s after fatigue. The present study shows that the sense of tension (peripherally) is also an important factor affecting force sense. Our study supports the view that the periphery is part of the origin of force sense.


Subject(s)
Hand Strength , Hand , Male , Humans , Female , Young Adult , Adult , Isometric Contraction , Muscle Fatigue , Muscle, Skeletal
6.
Atten Percept Psychophys ; 85(2): 474-484, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35794294

ABSTRACT

The purpose of the current investigation was to evaluate the effect of pinch span on the perception of pinch force in typical participants. The healthy participants (10 males and 10 females) conducted an ipsilateral force reproduction test with three distinct pinch spans (2, 4, and 6 cm) at three distinct forces of 10%, 30%, and 50% maximum voluntary isometric contraction. The findings revealed a significantly greater consistency (lower variable error (VE)) of 4 cm compared with 2 and 6 cm pinch spans. Our study also showed that the participants might use a larger force (more overestimated) output for larger pinch spans (4 and 6 cm) than small pinch spans (2 cm). These results may offer significant insights into the higher rates of musculoskeletal disorders among females, enabling researchers and clinicians to design novel interventions and tools to improve pinch force perception and reduce hand injury rates in males and females.


Subject(s)
Hand Strength , Isometric Contraction , Male , Female , Humans , Healthy Volunteers
9.
ACS Appl Mater Interfaces ; 13(39): 46909-46918, 2021 Oct 06.
Article in English | MEDLINE | ID: mdl-34550667

ABSTRACT

Small-molecule thermally activated delayed fluorescence (TADF) materials have been extensively developed to actualize efficient organic LEDs (OLEDs). However, organic small molecules generally compromise thin film quality and stability due to the tendency of crystallization, aggregation, and phase separation, which hence degrade the efficiency and long-term stability of the OLEDs. Here, for the first time, we exploit the unique molecular configuration of the bimesitylene scaffold to design two highly efficient TADF amorphous molecular materials with excellent thermal and morphological stabilities. The twisted and rigid bimesitylene scaffold thwarts regular molecular packing and crystallization, thereby guaranteeing homogeneous and stable amorphous thin films. Meanwhile, the highly twisted geometry of the bimesitylene scaffold efficiently breaks the molecular conjugation and thus conserves the high energies of the lowest locally excited triplet states (3LE) above the lowest charge transfer states (1CT and 3CT), leading to small singlet-triplet energy splitting and fast reverse intersystem crossing. These TADF emitters exhibit high photoluminescence quantum yields of 0.90 and 0.69 and short TADF lifetimes of 4.94 and 1.44 µs in doped films, based on which the greenish-blue and greenish-yellow OLEDs achieve external quantum efficiencies of 23.2 and 16.2%, respectively, with small efficiency roll-off rates and perfect color stability.

10.
World Neurosurg ; 2020 Jan 16.
Article in English | MEDLINE | ID: mdl-31954894

ABSTRACT

PURPOSE: To investigate whether arterial infundibular widening is a preaneurysmal lesion or not. METHODS: Two hundred and nine patients with cerebral angiography were enrolled. The morphology, size and location of infundibula and cerebral aneurysms were studied in two-dimensional angiography and three-dimensional software space. Computational fluid dynamics (CFD) analysis was performed. RESULTS: 234 infundibula and 129 infundibulum-like aneurysms (IFAs) were detected. In two-dimensional space, the typical morphology of an infundibulum was a symmetric dilatation at the arterial branch origin with a small vessel branch emanating from the tip and a wide base connecting the parent artery. In three-dimensional space, the infundibulum was dissymmetric with always one side longer than the other side. Furthermore, the infundibulum tilted upstream rather than downstream, with the longer side located downstream and the shorter side upstream in all cases. All the 129 IFAs occurred on the distal wall of the vessel branch origin, and no IFAs grew from the proximal wall of the branch origin. The possible development process of an infundibulum to an IFA was described in four development stages. The CFD analysis revealed that these lesions were associated with direct flow impingement in all cases. All the hemodynamic parameters on the distal wall of infundibula and IFAs were significantly (P<0.0001 or P<0.05) decreased compared with on the distal wall after virtual lesion removal. CONCLUSION: The infundibulum is a preaneurysmal lesion associated with high total pressure and high wall shear stress resulted from direct flow impingement and will progress to an aneurysm with time.

11.
Sci Rep ; 9(1): 17144, 2019 11 20.
Article in English | MEDLINE | ID: mdl-31748590

ABSTRACT

In order to investigate the role of lateral angle ratio (LA ratio) and daughter artery ratio (DA ratio) for predicting aneurysmal presence in main cerebral arterial bifurcations, three-dimensional cerebral angiographic data of major cerebral artery bifurcations were used for measurement of artery diameters and bifurcation angles including 115 middle cerebral arteries (MCAs), 59 basilar arteries (BAs), 35 internal carotid arteries (ICAs) and 115 anterior cerebral arteries (ACAs) with bifurcation aneurysms and control subjects of 1921 bifurcations with no aneurysms. The LA ratio (larger lateral angle/smaller lateral angle) and DA ratio (larger branch diameter/smaller branch diameter) were calculated, and ROC curve analysis of LA and DA ratios between normal and aneurysmal cases was performed. The LA and DA ratios of MCA bifurcations and the LA ratios of BA and ICA bifurcations with aneurysms were all significantly larger than normal bifurcations (P < 0.05), and the DA ratio of ACA bifurcations with aneurysms was significantly smaller than normal cases (P < 0.01). Moreover, the LA ratio or DA ratio between the normal and aneurysm cases in MCA, BA and ACA bifurcations demonstrated significant differences by ROC analysis (P < 0.01) except in the ICA bifurcations. No significant difference was observed (P > 0.05) between ruptured and unruptured aneurysms in MCA, BA, ICA and ACA bifurcations. In summary, normal MCA, BA and ICA bifurcations show symmetrical morphology in the lateral angles and daughter branches, whereas aneurysmal bifurcations show asymmetrical morphology. Normal ACA bifurcations have asymmetrical bilateral daughter branches while symmetrical branches are associated with ACA bifurcation aneurysm presence.

12.
Sci Rep ; 9(1): 15255, 2019 10 24.
Article in English | MEDLINE | ID: mdl-31649321

ABSTRACT

The objective of this study was to elucidate possible relationship between middle cerebral artery (MCA) bifurcation aneurysms and bifurcation morphology. In the present study, 799 patients with three-dimensional angiography were enrolled, including 115 patients with MCA bifurcation aneurysms and 684 subjects without aneurysms. The MCA bifurcation geometry, including angles formed between two M2 segments (φ1) and between M1 and M2 segments, vessel diameters and aneurysm sizes were measured. DA ratio (larger/smaller M2 in diameter) and LA ratio (larger/smaller lateral angle) were also analyzed. The LA and DA ratios and angle φ1 were significantly (P < 0.0001) greater in patients harboring MCA bifurcation aneurysms than in the control, whereas lateral angles and bifurcation branch diameters were significantly smaller (P < 0.01) in patients with than without bifurcation aneurysms. Angle φ1 was significantly increased (P < 0.0001) while both lateral angles significantly decreased (P < 0.0001 and P = 0.0005, respectively) with increase of patients' age. The size of MCA bifurcation aneurysms was significantly (P < 0.05) positively correlated with the bifurcation vascular diameter and aneurysm neck at the MCA bifurcation. A significantly positive correlation existed between aneurysm neck and DA ratio (P = 0.0075), whereas an inverse correlation between aneurysm neck and LA ratio (P = 0.0219). MCA bifurcation aneurysms were mostly deviated toward the smaller lateral angles and smaller M2 branch. In conclusion, aneurysmal MCA bifurcations have asymmetrical bifurcation structures with widened bifurcation angles, narrowed lateral angles, decreased M1 diameter, imbalanced lateral angles and M2 segments, with the cutoff bifurcation angle of 125.0° and cutoff lateral angle ratio of 1.57 for predicting MCA bifurcation aneurysms, whereas normal MCA bifurcations show close to symmetrical structures in the lateral angles and M2 branches.


Subject(s)
Intracranial Aneurysm/diagnostic imaging , Middle Cerebral Artery/diagnostic imaging , Adult , Aged , Cerebral Angiography , Female , Humans , Imaging, Three-Dimensional , Magnetic Resonance Angiography , Male , Middle Aged
13.
World Neurosurg ; 121: e379-e388, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30266713

ABSTRACT

OBJECTIVE: To investigate hemodynamic stresses on anterior cerebral artery bifurcation apex and possible mechanism of the optimality principle in protecting bifurcation wall from supercharged hemodynamic stresses. METHODS: Three-dimensional angiographic datasets of 122 patients with anterior communicating artery (Acom) aneurysms, 21 patients with non-Acom aneurysms, and 220 control subjects with no aneurysms were used. Radii of parent (r0) and daughter branches (r1 and r2) were measured, and bifurcations obeying the optimality principle required optimal caliber control of r0n = r1n + r2n, with the junction exponent n approximating 3. Radius ratio = r03/(r13 + r23) and n were compared between aneurysmal and control bifurcations. Blood flow was simulated for analysis of hemodynamic stresses. RESULTS: Acom bifurcations in subjects without Acom aneurysms displayed optimal caliber radius, with mean radius ratio of 0.99 and n of 3.25, whereas Acom aneurysmal bifurcations had significantly lower radius ratio, 0.62 (P < 0.05), but higher n, 4.23 (P < 0.05). Peak wall shear stress and corresponding total pressure were significantly smaller for bifurcations obeying than disobeying the optimality principle (P < 0.001 and P < 0.05, respectively). Total pressures in the direct impinging center, peak wall shear stress distance, and anterior cerebral artery bifurcation angle all were significantly smaller for bifurcations obeying than disobeying the optimality principle (P < 0.05 and P < 0.001, respectively). CONCLUSIONS: Normal anterior cerebral artery bifurcations obey the optimality principle whereas bifurcations with Acom aneurysms do not. Disobeying the optimality principle presents significantly enhanced hemodynamic stresses to possibly damage the bifurcation wall for aneurysm initiation.


Subject(s)
Anterior Cerebral Artery/physiopathology , Hemodynamics/physiology , Intracranial Aneurysm/diagnostic imaging , Intracranial Aneurysm/physiopathology , Middle Cerebral Artery/physiopathology , Anterior Cerebral Artery/diagnostic imaging , Cerebral Angiography , Female , Humans , Hydrodynamics , Imaging, Three-Dimensional , Male , Middle Cerebral Artery/diagnostic imaging , Statistics, Nonparametric , Stress, Mechanical , Subarachnoid Hemorrhage/diagnostic imaging , Subarachnoid Hemorrhage/etiology
14.
World Neurosurg ; 120: e783-e791, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30176397

ABSTRACT

OBJECTIVE: To investigate the relationship of anterior cerebral artery (ACA) bifurcation angles with hemodynamic stresses for aneurysm initiation. METHODS: Forty patients with or without anterior communicating artery aneurysms were enrolled, and 3 patients with ACA bifurcation angles of 169.0°, 136.9°, and 73.2°, respectively, were entered into computational fluid dynamics analysis for hemodynamic stresses. RESULTS: Larger bifurcation angles had a larger direct flow impinging zone and larger peak pressure area. In the direct flow impinging center, the total pressure was the highest, whereas the other stresses were the lowest. As blood flowed distally, the total pressure decreased rapidly, whereas all other parameters increased quickly to their peaks. The hemodynamic peak distance was decreased as the bifurcation angle became narrower. The total pressure summit and the peak hemodynamic stresses all decreased with the decrease of bifurcation angles. The distance between the hemodynamic peaks was the smallest at 73.2° compared with larger angles. A significant (P < 0.01) positive linear correlation existed in the ACA bifurcation angle with the distance between hemodynamic stress peaks or in the ACA branch diameter with the distance from the direct impinging center to the ipsilateral hemodynamic stress peak. The hemodynamic stresses on the aneurysm dome were significantly (P < 0.001) smaller than at the aneurysm initiation site. CONCLUSIONS: Larger bifurcation angles may lead to abnormally enhanced hemodynamic stresses, enlarged zones of direct flow impingement, and increased distance between hemodynamic stress peaks to damage the vascular wall for aneurysm initiation on the bifurcation apex wall.


Subject(s)
Anterior Cerebral Artery/pathology , Anterior Cerebral Artery/physiopathology , Hemodynamics , Intracranial Aneurysm/pathology , Intracranial Aneurysm/physiopathology , Stress, Physiological , Adult , Aged , Aged, 80 and over , Anterior Cerebral Artery/diagnostic imaging , Cerebral Angiography , Computer Simulation , Disease Susceptibility , Female , Humans , Hydrodynamics , Intracranial Aneurysm/diagnostic imaging , Male , Middle Aged , Models, Cardiovascular , Models, Neurological
15.
Stroke ; 49(6): 1371-1376, 2018 06.
Article in English | MEDLINE | ID: mdl-29724891

ABSTRACT

BACKGROUND AND PURPOSE: Basilar artery (BA) bifurcation aneurysms are common, but the correlation between BA bifurcation morphology and aneurysm formation remains to be established. Our purpose was to determine the association of BA bifurcation aneurysms with patient age, sex, bifurcation angle, and branch diameter. METHODS: Three-dimensional angiographic data of 195 patients were used, including 59 patients with BA bifurcation aneurysms and 136 control subjects. The angles formed between left and right posterior cerebral arteries (φ1) and between posterior cerebral artery and BA (the smaller angle defined as φ2 and the larger one as φ3), arterial diameters, and BA bifurcation aneurysm geometric characters were examined. RESULTS: Women of 40 to 70 years of age are more vulnerable to BA bifurcation aneurysm formation than men. The φ1 bifurcation angle significantly increased (P<0.0001), whereas both φ2 and φ3 angles significantly decreased (P<0.0001 and P=0.09, respectively) with increase of patients' age. Statistically significant (P<0.0001 and P=0.0002, respectively) positive correlations were observed between BA bifurcation branch diameter and aneurysm size. The φ1 angle was significantly (P<0.0001) wider in patients harboring BA bifurcation aneurysms than the control, whereas φ2 and φ3 angles in aneurysm group were significantly smaller than those in the control group (P<0.0001). The BA bifurcation aneurysms were mostly deviated toward the smaller φ2 angle side between φ2 and φ3 angles and deviated toward the smaller-diameter daughter posterior cerebral artery branch. CONCLUSIONS: BA bifurcation aneurysms are significantly associated with patients' age, female sex, wider bifurcation angles, and smaller vascular diameter at the BA bifurcation.


Subject(s)
Age Factors , Imaging, Three-Dimensional , Intracranial Aneurysm/epidemiology , Sex Factors , Adult , Aged , Aged, 80 and over , Basilar Artery/diagnostic imaging , Cerebral Angiography/methods , Female , Humans , Intracranial Aneurysm/diagnosis , Male , Middle Aged , Middle Cerebral Artery/diagnostic imaging , Posterior Cerebral Artery/diagnostic imaging
16.
Burns ; 44(4): 905-916, 2018 06.
Article in English | MEDLINE | ID: mdl-29449035

ABSTRACT

BACKGROUND: Burn-blast combined injury is a kind of injury caused by heat and blast at the same time. The lung injury after burn-blast combined injuries is of primary importance, and investigation of lung injury is needed in the clinical care of patients. Computed tomography (CT) is one of the standard tools used to observe the anatomical basis and pathophysiology of acute lung injury. METHODS: We applied a method of fast 3D (three-dimensional) reconstruction to calculate the density value of the lung injury by CT analysis. Blast-injury group (BL group), burn-injury group (B group), burn-blast combined injury group (BBL group), and sham control group (C group) were established. Each group had 16 rats. The three-dimensional images of the lung tissue were obtained at 6h, 24h, and 48h according to the CT value. The average density of the whole lung, left lung, and right lung were measured. The lung tissues were paraffin-embedded and HE stained. Smith scoring was performed according to the pathological findings. RESULTS: In the BBL group, the density of the lung tissue was higher than those of the BL group and B group (P<0.01). The lung tissue density values at 24h after injury were higher than those at 6h and 48h after injury (P<0.01). Pathological results confirmed the changes of density analysis of the lung tissue. CONCLUSION: The results have indicated that density analysis through a CT scan can be used as a way to evaluate lung injury in a burn-blast injury.


Subject(s)
Acute Lung Injury/diagnostic imaging , Blast Injuries/diagnostic imaging , Burns/complications , Explosions , Acute Lung Injury/complications , Acute Lung Injury/pathology , Animals , Blast Injuries/complications , Blast Injuries/pathology , Body Surface Area , Imaging, Three-Dimensional , Lung/diagnostic imaging , Lung/pathology , Male , Rats , Rats, Sprague-Dawley , X-Ray Microtomography
17.
Stroke ; 49(2): 341-347, 2018 02.
Article in English | MEDLINE | ID: mdl-29301972

ABSTRACT

BACKGROUND AND PURPOSE: The anterior communicating artery (Acom) aneurysm is the most complex in all cerebral aneurysms, and wider vascular bifurcation angles are considered to be associated with aneurysm formation. The objective of this study was to investigate association of the Acom aneurysm formation with patient age and vascular bifurcation morphology. METHODS: Three-dimensional angiographic data of 665 patients were used in this study, including 160 patients with Acom aneurysms, 66 with non-Acom aneurysms, and 439 control subjects with no aneurysms. The anterior cerebral artery bifurcation angle (Acom/A2 angle), arterial diameters, and Acom aneurysm geometric characters were examined. RESULTS: Women of 50 to 70 years were more vulnerable to Acom aneurysm formation than men. The Acom/A2 bifurcation angle was significantly increased (P<0.0001) with increase of patient age. The size of the Acom aneurysm dome and neck was statistically positively correlated with the diameter of the Acom, A1 and A2 segments (P<0.0001). The Acom/A2 bifurcation angle was significantly (P<0.0001) wider in patients with than without Acom aneurysms, whereas the A1/A2 angle was significantly smaller in patients with than without Acom aneurysms (P<0.0001). The Acom aneurysms at the bifurcation apex mostly deviated toward the smaller angle formed between the parent A1 and branches and toward the daughter artery with a smaller diameter. The Acom aneurysms were located mostly on the dominant anterior cerebral artery. CONCLUSIONS: The presence of Acom aneurysm is significantly associated with patient age, wider angles of the anterior cerebral artery bifurcation, and smaller vascular diameter of the anterior communicating complex.


Subject(s)
Anterior Cerebral Artery/diagnostic imaging , Intracranial Aneurysm/etiology , Age Factors , Aged , Aneurysm, Ruptured , Cerebral Angiography/methods , Female , Humans , Intracranial Aneurysm/diagnostic imaging , Middle Aged
18.
Interv Neuroradiol ; 23(3): 325-329, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28152631

ABSTRACT

Objective The aim of this study was to construct an in vivo carotid siphon model for testing neurovascular devices for endovascular interventions. Methods A model of a human carotid siphon was pre-shaped using a glass tube from a human cadaver and used to confine a segment of one side of the common carotid artery (CCA) in canines. This segment of CCA with the glass carotid siphon on was interposed end-to-end onto the contralateral CCA so as to simulate a human carotid artery siphon in vivo. Two weeks later, the siphon model was evaluated using computed tomography angiography and digital subtraction angiography, and the covered stent specially designed for intracranial vasculature was navigated through the siphon model for a longitudinal flexibility test. Results All dogs tolerated the procedures well, and the artificial siphon model in vivo provided realistic conditions for device testing. Two weeks later, the in vivo carotid siphon model remained patent with no thrombosis. Five covered stents were navigated to pass through five siphon models successfully, with vasospasm occurring in two siphons. Conclusion Construction of an in vivo siphon model in dogs with a glass tube is feasible and useful for the test of endovascular devices for treating neurovascular diseases.


Subject(s)
Carotid Artery, Common/surgery , Endovascular Procedures/instrumentation , Angiography, Digital Subtraction , Animals , Cerebral Angiography , Cerebrovascular Disorders/surgery , Computed Tomography Angiography , Disease Models, Animal , Dogs , Equipment Design , Glass , Models, Cardiovascular
19.
Int J Pharm ; 507(1-2): 90-101, 2016 Jun 30.
Article in English | MEDLINE | ID: mdl-27154251

ABSTRACT

The aim of the present study was to investigate the potential application of (+)-camphor as a penetration enhancer for the transdermal delivery of drugs with differing lipophilicity. The skin irritation of camphor was evaluated by in vitro cytotoxicity assays and in vivo transdermal water loss (TEWL) measurements. A series of model drugs with a wide span of lipophilicity (logP value ranging from 3.80 to -0.95), namely indometacin, lidocaine, aspirin, antipyrine, tegafur and 5-fluorouracil, were tested using in vitro transdermal permeation experiments to assess the penetration-enhancing profile of camphor. Meanwhile, the in vivo skin microdialysis was carried out to further investigate the enhancing effect of camphor on the lipophilic and hydrophilic model drugs (i.e. lidocaine and tegafur). SC (stratum corneum)/vehicle partition coefficient and Fourier transform infrared spectroscopy (FTIR) were performed to probe the regulation action of camphor in the skin permeability barrier. It was found that camphor produced a relatively low skin irritation, compared with the frequently-used and standard penetration enhancer laurocapram. In vitro skin permeation studies showed that camphor could significantly facilitate the transdermal absorption of model drugs with differing lipophilicity, and the penetration-enhancing activities were in a parabola curve going downwards with the drug logP values, which displayed the optimal penetration-enhancing efficiency for the weak lipophilic or hydrophilic drugs (an estimated logP value of 0). In vivo skin microdialysis showed that camphor had a similar penetration behavior on transdermal absorption of model drugs. Meanwhile, the partition of lipophilic drugs into SC was increased after treatment with camphor, and camphor also produced a shift of CH2 vibration of SC lipid to higher wavenumbers and decreased the peak area of the CH2 vibration, probably resulting in the alteration of the skin permeability barrier. This suggests that camphor might be a safe and effective penetration enhancer for transdermal drug delivery.


Subject(s)
Camphor/pharmacology , Hydrophobic and Hydrophilic Interactions , Lidocaine/pharmacokinetics , Pharmaceutical Preparations/metabolism , Skin Absorption/drug effects , Skin/drug effects , Tegafur/pharmacokinetics , Administration, Cutaneous , Animals , Camphor/administration & dosage , Camphor/adverse effects , Cell Survival/drug effects , Cells, Cultured , Rats , Skin/metabolism
20.
Adv Healthc Mater ; 5(14): 1740-52, 2016 07.
Article in English | MEDLINE | ID: mdl-27113724

ABSTRACT

Osteoporosis is becoming more prevalent due to the aging demographics of many populations. Osteoporotic bone is more prone to fracture than normal bone, and current orthopedic implant materials are not ideal for the osteoporotic cases. A newly developed strontium phosphate (SrPO4 ) coating is reported herein, and applied to Ti-29Nb-13Ta-4.6Zr (wt%), TNTZ, an implant material with a comparative Young's modulus to that of natural bone. The SrPO4 coating is anticipated to modulate the activity of osteoblast (OB) and osteoclast (OC) cells, in order to promote bone formation. TNTZ, a material with excellent biocompatibility and high bioinertness is pretreated in a concentrated alkaline solution under hydrothermal conditions, followed by a hydrothermal coating growth process to achieve complete SrPO4 surface coverage with high bonding strength. Owing to the release of Sr ions from the SrPO4 coating and its unique surface topography, OB cells demonstrate increased proliferation and differentiation, while the cellular responses of OC are suppressed, compared to the control case, i.e., bare TNTZ. This TNTZ implant with a near physiologic Young's modulus and a functional SrPO4 coating provides a new direction in the design and manufacture of implantable devices used in the management of orthopedic conditions in osteoporotic individuals.


Subject(s)
Alloys/chemistry , Bone Substitutes/chemistry , Coated Materials, Biocompatible/chemistry , Materials Testing , Osteoblasts/metabolism , Phosphates/chemistry , Strontium/chemistry , Adult , Humans , Male , Middle Aged , Osteoblasts/cytology
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