We have used molecular dynamics to calculate the thermal conductivity of symmetric and asymmetric graphene nanoribbons (GNRs) of several nanometers in size (up to ∼4 nm wide and ∼10 nm long). For ...symmetric nanoribbons, the calculated thermal conductivity (e.g., ∼2000 W/m-K at 400 K for a 1.5 nm × 5.7 nm zigzag GNR) is on the similar order of magnitude of the experimentally measured value for graphene. We have investigated the effects of edge chirality and found that nanoribbons with zigzag edges have appreciably larger thermal conductivity than nanoribbons with armchair edges. For asymmetric nanoribbons, we have found significant thermal rectification. Among various triangularly shaped GNRs we investigated, the GNR with armchair bottom edge and a vertex angle of 30° gives the maximal thermal rectification. We also studied the effect of defects and found that vacancies and edge roughness in the nanoribbons can significantly decrease the thermal conductivity. However, substantial thermal rectification is observed even in the presence of edge roughness.
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IJS, KILJ, NUK, PNG, UL, UM
Background and purpose
An increasing interest in the potential benefits of cognitive motor interference (CMI) for stroke has recently been observed, but the efficacy of CMI for gait and balance is ...controversial. A systematic review and meta‐analysis of randomized controlled trials was performed to estimate the effect of CMI on gait and balance in patients with stroke.
Methods
Articles in Medline, EMBASE, the Cochrane Library, Web of Science, CINAHL, PEDro and the China Biology Medicine disc were searched from 1970 to July 2014. Only randomized controlled trials examining the effects of CMI for patients with stroke were included, and no language restrictions were applied. Main outcome measures included gait and balance function.
Results
A total of 15 studies composed of 395 participants met the inclusion criteria, and 13 studies of 363 participants were used as data sources for the meta‐analysis. Pooling revealed that CMI was superior to the control group for gait speed mean difference (MD) 0.19 m/s, 95% confidence interval (CI) (0.06, 0.31), P = 0.003, stride length MD 12.53 cm, 95% CI (4.07, 20.99), P = 0.004, cadence MD 10.44 steps/min, 95% CI (4.17, 16.71), P = 0.001, centre of pressure sway area MD −1.05, 95% CI (−1.85, −0.26), P = 0.01 and Berg balance scale MD 2.87, 95% CI (0.54, 5.21), P = 0.02 in the short term.
Conclusion
Cognitive motor interference is effective for improving gait and balance function for stroke in the short term. However, only little evidence supports assumptions regarding CMI's long‐term benefits.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Topological insulators are a novel class of quantum matter with a gapped insulating bulk, yet gapless spin-helical Dirac fermion conducting surface states. Here, we report local and non-local ...electrical and magneto transport measurements in dual-gated BiSbTeSe2 thin film topological insulator devices, with conduction dominated by the spatially separated top and bottom surfaces, each hosting a single species of Dirac fermions with independent gate control over the carrier type and density. We observe many intriguing quantum transport phenomena in such a fully tunable two-species topological Dirac gas, including a zero-magnetic-field minimum conductivity close to twice the conductance quantum at the double Dirac point, a series of ambipolar two-component half-integer Dirac quantum Hall states and an electron-hole total filling factor zero state (with a zero-Hall plateau), exhibiting dissipationless (chiral) and dissipative (non-chiral) edge conduction, respectively. Such a system paves the way to explore rich physics, ranging from topological magnetoelectric effects to exciton condensation.
When a two-dimensional (2D) electron gas is placed in a perpendicular magnetic field, its in-plane transverse conductance becomes quantized; this is known as the quantum Hall effect. It arises from ...the non-trivial topology of the electronic band structure of the system, where an integer topological invariant (the first Chern number) leads to quantized Hall conductance. It has been shown theoretically that the quantum Hall effect can be generalized to four spatial dimensions, but so far this has not been realized experimentally because experimental systems are limited to three spatial dimensions. Here we use tunable 2D arrays of photonic waveguides to realize a dynamically generated four-dimensional (4D) quantum Hall system experimentally. The inter-waveguide separation in the array is constructed in such a way that the propagation of light through the device samples over momenta in two additional synthetic dimensions, thus realizing a 2D topological pump. As a result, the band structure has 4D topological invariants (known as second Chern numbers) that support a quantized bulk Hall response with 4D symmetry. In a finite-sized system, the 4D topological bulk response is carried by localized edge modes that cross the sample when the synthetic momenta are modulated. We observe this crossing directly through photon pumping of our system from edge to edge and corner to corner. These crossings are equivalent to charge pumping across a 4D system from one three-dimensional hypersurface to the spatially opposite one and from one 2D hyperedge to another. Our results provide a platform for the study of higher-dimensional topological physics.
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IJS, KISLJ, NUK, SBMB, UL, UM, UPUK
A mathematical model of interstitial fluid flow is developed, based on the application of the governing equations for fluid flow, i.e., the conservation laws for mass and momentum, to physiological ...systems containing solid tumors. The discretized form of the governing equations, with appropriate boundary conditions, is developed for a predefined tumor geometry. The interstitial fluid pressure and velocity are calculated using a numerical method, element based finite volume. Simulations of interstitial fluid transport in a homogeneous solid tumor demonstrate that, in a uniformly perfused tumor, i.e., one with no necrotic region, because of the interstitial pressure distribution, the distribution of drug particles is non-uniform. Pressure distribution for different values of necrotic radii is examined and two new parameters, the critical tumor radius and critical necrotic radius, are defined. Simulation results show that: 1) tumor radii have a critical size. Below this size, the maximum interstitial fluid pressure is less than what is generally considered to be effective pressure (a parameter determined by vascular pressure, plasma osmotic pressure, and interstitial osmotic pressure). Above this size, the maximum interstitial fluid pressure is equal to effective pressure. As a consequence, drugs transport to the center of smaller tumors is much easier than transport to the center of a tumor whose radius is greater than the critical tumor radius; 2) there is a critical necrotic radius, below which the interstitial fluid pressure at the tumor center is at its maximum value. If the tumor radius is greater than the critical tumor radius, this maximum pressure is equal to effective pressure. Above this critical necrotic radius, the interstitial fluid pressure at the tumor center is below effective pressure. In specific ranges of these critical sizes, drug amount and therefore therapeutic effects are higher because the opposing force, interstitial fluid pressure, is low in these ranges.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract We performed an analysis of the extreme-ultraviolet (EUV) wave event on 2022 March 31. The event originated from active region (AR) 12975 located at N13W52 in the field of view of the ...Atmospheric imaging Assembly (AIA) and exactly at the west limb viewed by the EUV Imager (EUVI) of the Solar Terrestrial Relations Observatory-Ahead (STEREO-A) satellite. The EUV wave was associated with an M9.6 class flare. The event was also well observed by Mauna Loa Solar Observatory and COR1 coronagraphs. We revealed here evident coexistence of two components of EUV waves in AIA as well as in EUVI images, i.e., a fast-mode wave and a nonwave, which was predicted by the EUV wave hybrid model. The speeds of the fast-mode and nonwave EUV wave components in AIA vary from ∼430 to 658 km s −1 and ∼157 to 205 km s −1 , respectively. The computed speeds in STEREO-A for the fast-mode wave and nonwave components are ∼520 and ∼152 km s −1 , respectively. Another wave emanated from the source AR and interacted with ambient coronal loops, showing evident reflection in the EUV images above the solar limb. The speed of the reflected wave in the plane of the sky is ∼175 km s −1 . With the precise alignments, we found that the fast-mode EUV wave is just ahead of the coronal mass ejection (CME), and the nonwave component is cospatial with the frontal loop of the accompanied CME. The event also showed stationary fronts.
Interface-induced effect of nanocomposites are attracting many attentions because the potential advantages in environment decontamination. This work present the synthesis and enhanced photocatalytic ...activities of novel reduced graphene oxide-ZnFe
2
O
4
nanocomposites. The nanocomposites showed obviously greater sunlight-excited photocatalytic and Fenton-like photocatalytic activities than the nanoparticles. The photocatalytic activities enhanced with increasing rGO/ZnFe
2
O
4
ratio and related with initial pH and H
2
O
2
content. The good photocatalytic activities are ascribed to the interface charge transfer that is confirmed by optical conducitivity. Moreover, the nanoparticles and nanocomposites was ferromagnetic, thereby being magnetically separable. The nanocomposites also showed good adsorption ability to the dye, and so the remained dye and intermediates can be magnetically removed together with the reusable nanocomposites.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Modeling of interstitial fluid flow involves processes such as fluid diffusion, convective transport in extracellular matrix, and extravasation from blood vessels. To date, majority of microvascular ...flow modeling has been done at different levels and scales mostly on simple tumor shapes with their capillaries. However, with our proposed numerical model, more complex and realistic tumor shapes and capillary networks can be studied. Both blood flow through a capillary network, which is induced by a solid tumor, and fluid flow in tumor's surrounding tissue are formulated. First, governing equations of angiogenesis are implemented to specify the different domains for the network and interstitium. Then, governing equations for flow modeling are introduced for different domains. The conservation laws for mass and momentum (including continuity equation, Darcy's law for tissue, and simplified Navier-Stokes equation for blood flow through capillaries) are used for simulating interstitial and intravascular flows and Starling's law is used for closing this system of equations and coupling the intravascular and extravascular flows. This is the first study of flow modeling in solid tumors to naturalistically couple intravascular and extravascular flow through a network. This network is generated by sprouting angiogenesis and consisting of one parent vessel connected to the network while taking into account the non-continuous behavior of blood, adaptability of capillary diameter to hemodynamics and metabolic stimuli, non-Newtonian blood flow, and phase separation of blood flow in capillary bifurcation. The incorporation of the outlined components beyond the previous models provides a more realistic prediction of interstitial fluid flow pattern in solid tumors and surrounding tissues. Results predict higher interstitial pressure, almost two times, for realistic model compared to the simplified model.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Retinal ganglion cells (RGCs) are the sole output neurons that transmit visual information from the retina to the brain. Diverse insults and pathological states cause degeneration of RGC somas and ...axons leading to irreversible vision loss. A fundamental question is whether manipulation of a key regulator of RGC survival can protect RGCs from diverse insults and pathological states, and ultimately preserve vision. Here, we report that CaMKII-CREB signaling is compromised after excitotoxic injury to RGC somas or optic nerve injury to RGC axons, and reactivation of this pathway robustly protects RGCs from both injuries. CaMKII activity also promotes RGC survival in the normal retina. Further, reactivation of CaMKII protects RGCs in two glaucoma models where RGCs degenerate from elevated intraocular pressure or genetic deficiency. Last, CaMKII reactivation protects long-distance RGC axon projections in vivo and preserves visual function, from the retina to the visual cortex, and visually guided behavior.
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•Excitotoxic and axonal injuries lead to loss of CaMKII activity in RGCs•Reactivation of CaMKII protects RGCs in multiple injury/disease models•CREB acts downstream of CaMKII in protecting RGCs•Reactivation of CaMKII protects visual pathway and preserves functional vision
CaMKII-CREB signaling plays a major role in maintenance of retinal ganglion cells (RGCs), and reactivation of CaMKII activity via AAV gene therapy in injury and disease models in mice protects RGCs and preserves visual function and visually guided behavior.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The metabolic syndrome may cause disease progression in patients with chronic hepatitis B (CHB). However, the interactions between hepatitis B virus (HBV) infection and metabolic factors remain ...unknown. We investigated the association of HBV infection with metabolic profiles in HBV‐infected and noninfected subjects. In addition, the impacts of serum HBV DNA level on metabolic profiles were studied. Initially, a case–control analysis of patients with and without chronic HBV infection was performed. The HBV group consisted of 322 patients with chronic HBV infection, and the control group consisted of 870 matched subjects without HBV infection. Fasting blood glucose, lipid profiles and adiponectin levels were compared. The results were then confirmed in a second retrospective cohort study in 122 CHB patients with serum HBV DNA levels and HOMA‐IR index values. In the case–control analysis, the HBV group had significantly higher serum adiponectin, but lower triglyceride (TG) and high‐density lipoprotein cholesterol (HDL) levels than the control group. These relationships already existed in subjects younger than 45 years of age and were modified by serum alanine aminotransferase (ALT) levels. In the retrospective cohort, serum HBV DNA levels were negatively proportional to TG levels, but not to other metabolic parameters. Moreover, this relationship was significant only in subjects with higher ALT levels. Compared with healthy adults, patients with chronic HBV infection have significantly higher serum adiponectin, but lower TG and HDL levels. These relationships are modified by ALT levels and already exist in middle‐age patients with chronic HBV infection, implying HBV may interact with host metabolism.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
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