3,584 research outputs found

    Controllability analysis of directed networks in finite states based on pruning motif isomorph

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    The current driver nodes search methods are difficult to cope with large networks, and the solution process does not consider the node cost. In order to solve the practical control problem of networks with different node costs in finite states, this paper proposes a pruning and motif isomorph search method for driver node set. Firstly, we prove the sufficient conditions for the network to be strictly controllable under partial nodes control, then we classify the nodes and prove the equivalence controllability of the pruning network, and then we establish three models of maximum augmenting path search, local pruning and motif matching to form a complete driver nodes set search algorithm. Finally, the algorithm is validated by real networks. The results show that our method not only guarantee the accuracy of search results, but also has the low time complexity, which can efficiently handle large networks, and no more than 16.84% of the maximum driver nodes can control the whole network

    Geometric and Electronic Structure of Graphene Bilayer Edges

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    We present a computational investigation of free-standing graphene bilayer edge (BLE) structures, aka “fractional nanotubes.” We demonstrate that these curved carbon nanostructures possess a number of interesting properties, electronic in origin. The BLEs, quite atypical of elemental carbon, have large permanent electric dipoles of 0.87 and 1.14 debye/Å for zigzag and armchair inclinations, respectively. An unusual, weak AA interlayer coupling leads to a twinned double-cone dispersion of the electronic states near the Dirac points. This entails a type of quantum Hall behavior markedly different from what has been observed in graphenebased materials, characterized by a magnetic field-dependent resonance in the Hall conductivity

    Daily Costs and Cost Effectiveness of Glaucoma Fixed Combinations in China

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    Background. The aim of this study was to compare the daily costs and cost effectiveness of fixed combination glaucoma drugs in China. Methods. This study included the following fixed combination drugs: brinzolamide 1% and timolol 0.5% (Azarga; Alcon, Inc., Fort Worth, TX, USA), travoprost 0.004% and timolol 0.5% (DuoTrav; Alcon, Inc.), bimatoprost 0.03% and timolol 0.5% (Ganfort; Allergan, Inc., Dublin, Ireland), and latanoprost 0.005% and timolol 0.5% (Xalacom; Pfizer, Inc., New York, NY, USA). Five bottles of each drug were measured. The mean actual volume, mean actual number of drops, volume per drop, daily cost, yearly cost, and per mmHg reduction cost for each drug were calculated. Results. The volumes per drop ranged from 32.61 ± 2.90 μl (DuoTrav) to 24.38 ± 0.23 μl (Ganfort). The number of usage days per bottle varied from 36 days (DuoTrav) to 61 days (Ganfort). Azarga had the lowest daily cost (0.23)andyearlycost(0.23) and yearly cost (84.72), while DuoTrav had the highest daily cost (0.79)andyearlycost(0.79) and yearly cost (287.02). Azarga costed 2.172.17-3.30 per mmHg intraocular pressure reduction, which was lower than the other three drugs. For the prostaglandin and ß-adrenergic blocker FCs, Ganfort had the lowest daily cost (0.35)andpermmHgreductioncost(from0.35) and per mmHg reduction cost (from 3.40 to $4.04). Conclusions. The daily costs of these drugs were significantly different, with Azarga having the lowest daily cost and best cost effectiveness. For the prostaglandin and β-adrenergic blocker fixed combinations, Ganfort was the most economical choice with its lower daily cost and per mmHg reduction cost. The results of this study could provide drug selection guidance from an economic perspective, but various factors should be considered when making a decision.</p

    Anterior lens capsule:biomechanical properties and biomedical engineering perspectives

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    Anterior lens capsule, as the thickest basement membrane in the body, has its unique physiology characteristics. In ophthalmology, many attempts have been made to culture different kinds of cells including iris pigment epithelial cells, retinal pigment epithelial cells, corneal epithelium and endothelium cells, trabecular meshwork cells etc and anterior lens capsule has been confirmed to be served as an excellent scaffold for the growth and expansion of different ocular cells. Furthermore, anterior lens capsule also has unique potential in gestation evaluation and the treatment of various ocular diseases, including corneal ulcer, glaucoma, age-related macular degeneration and macular hole, etc. Here, we provide an overview of the biomechanical properties and biomedical engineering perspectives of anterior lens capsule

    The Leap of Comparative Advantage Trap in Guangzhou-Based on the Perspective of Global Value Chain

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    This paper analyzes the situation and reasons of the trap of comparative advantage in Guangzhou, and proposes some strategies on how to leap the trap of comparative advantage. Firstly, based on the perspective of global value chain, this paper analyzes the status of Guangzhou in the global value chain through RCA (revealed comparative advantage index) and RTV (revealed technology added value index), and illustrates the situation of Guangzhou in the trap of comparative advantage. Secondly, the reasons why Guangzhou is into comparative advantage trap are analyzed from three aspects, capital, labor force and technology. Thirdly, in view of the main reasons, we seek some effective strategies to leap the comparative advantage trap, promote the transformation and upgrading of enterprises in guangzhou into innovative enterprises, and lead to the promotion of the competitiveness of Guangzhou in the globalization division of labor

    Cerebral hemodynamic characteristics of acute mountain sickness upon acute high-altitude exposure at 3,700 m in young Chinese men.

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    PURPOSE: We aimed at identifying the cerebral hemodynamic characteristics of acute mountain sickness (AMS). METHODS: Transcranial Doppler (TCD) sonography examinations were performed between 18 and 24 h after arrival at 3,700 m via plane from 500 m (n = 454). A subgroup of 151 subjects received TCD examinations at both altitudes. RESULTS: The velocities of the middle cerebral artery, vertebral artery (VA) and basilar artery (BA) increased while the pulsatility indexes (PIs) and resistance indexes (RIs) decreased significantly (all p &lt; 0.05). Velocities of BA were higher in AMS (AMS+) individuals when compared with non-AMS (AMS-) subjects (systolic velocity: 66 ± 12 vs. 69 ± 15 cm/s, diastolic velocity: 29 ± 7 vs. 31 ± 8 cm/s and mean velocity, 42 ± 9 vs. 44 ± 10 cm/s). AMS was characterized by higher diastolic velocity [V d_VA (26 ± 4 vs. 25 ± 4, p = 0.013)] with lower PI and RI (both p = 0.004) in VA. Furthermore, the asymmetry index (AI) of VAs was significantly lower in the AMS + group [-5.7 % (21.0 %) vs. -2.5 % (17.8 %), p = 0.016]. The AMS score was closely correlated with the hemodynamic parameters of BA and the V d_VA, PI, RI and AI of VA. CONCLUSION: AMS is associated with alterations in cerebral hemodynamics in the posterior circulation rather than the anterior one, and is characterized by higher blood velocity with lower resistance. In addition, the asymmetry of VAs may be involved in AMS

    Transscleral cyclophotocoagulation followed by cataract surgery:a novel protocol to treat refractory acute primary angle closure

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    Background: To introduce a novel protocol to treat refractory acute primary angle closure (APAC): transscleral cyclophotocoagulation (TCP) followed by cataract surgery. Methods: Thirteen APAC eyes (13 patients) were enrolled in this prospective case series as study group. All patients underwent emergency TCP (20 pulses of 2000 mW during 2000 ms applied to the inferior quadrant) followed by scheduled cataract surgery. They were compared to 13 age- and gender-matched patients treated with emergency phacotrabeculectomy. We recorded intraocular pressure (IOP), best corrected visual acuity (BCVA), and complications, and several ultrasound biomicroscopy (UBM) parameters before and after TCP. Results: In the study group, IOP decreased from 51.5 +/- 7.0 mmHg (mean +/- standard deviation) before TCP to 16.4 +/- 5.4 mmHg 1 day after TCP (P <0.001). At 6 months, there was no significant difference in IOP between the study group (14.0 +/- 3.4 mmHg) and control group (16.7 +/- 4.3 mmHg;P = 0.090); IOP lowering medications were used by 0/13 in the study group and 2/13 patients in the control group (P = 0.48). At 6 months, there was no significant difference in BCVA between the study group and the control group (20/25 (20/200 to 20/25) and 20/30 (20/50 to 20/25), respectively;P = 1.0). The UBM parameters anterior chamber depth (P = 0.016), angle-opening distance at 500 mu m (P = 0.011), and maximum ciliary body thickness (P <0.001) increased significantly while the iris-ciliary process distance decreased significantly (P = 0.020) after TCP. Conclusions: TCP effectively lowers IOP and modifies the anterior chamber morphology in APAC; TCP followed by cataract surgery can be considered an alternative to treat refractory APAC but needs further evaluation
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