Nonlinear Flow Properties of Newtonian Fluids through Rough Crossed Fractures

The nonlinear flow properties of Newtonian fluids through crossed fractures are estimated by considering the influences of length,aperture,and surface roughness of fractures.A total of 252 computational runs are performed by creating 36 computational domains,in which the Navier-Stokes equations are solved.The results show that the nonlinear relationship between flow rate and hydraulic gradient follows Forchheimer’s law–based equation.When the hydraulic gradient is small(i.e.,10^(−6)),the streamlines are parallel to the fracture walls,indicating a linear streamline distribution.When the hydraulic gradient is large(i.e.,10^(0)),the streamlines are disturbed by a certain number of eddies,indicating a nonlinear streamline distribution.The patterns of eddy distributions depend on the length,aperture,and surface roughness of fractures.With the increment of hydraulic gradient from 10^(−6) to 10^(0),the ratio of flow rate to hydraulic gradient holds constants and then decreases slightly and finally decreases robustly.The fluid flow experiences a linear flow regime,a weakly nonlinear regime,and a strongly nonlinear regime,respectively.The critical hydraulic gradient ranges from 3.27×10^(−5) to 5.82×10^(−2) when fracture length=20–100mmandmechanical aperture=1–5mm.The joint roughness coefficient plays a negligible role in the variations in critical hydraulic gradient compared with fracture length and/or mechanical aperture.The critical hydraulic gradient decreases with increasing mechanical aperture,following power-law relationships.The parameters in the functions are associated with fracture length.

Point Cloud Classification Network Based on Graph Convolution and Fusion Attention Mechanism

The classification of point cloud data is the key technology of point cloud data information acquisition and 3D reconstruction, which has a wide range of applications. However, the existing point cloud classification methods have some shortcomings when extracting point cloud features, such as insufficient extraction of local information and overlooking the information in other neighborhood features in the point cloud, and not focusing on the point cloud channel information and spatial information. To solve the above problems, a point cloud classification network based on graph convolution and fusion attention mechanism is proposed to achieve more accurate classification results. Firstly, the point cloud is regarded as a node on the graph, the k-nearest neighbor algorithm is used to compose the graph and the information between points is dynamically captured by stacking multiple graph convolution layers;then, with the assistance of 2D experience of attention mechanism, an attention mechanism which has the capability to integrate more attention to point cloud spatial and channel information is introduced to increase the feature information of point cloud, aggregate local useful features and suppress useless features. Through the classification experiments on ModelNet40 dataset, the experimental results show that compared with PointNet network without considering the local feature information of the point cloud, the average classification accuracy of the proposed model has a 4.4% improvement and the overall classification accuracy has a 4.4% improvement. Compared with other networks, the classification accuracy of the proposed model has also been improved.

Inhibition of Sirtuin 2 exerts neuroprotection in aging rats with increased neonatal iron intake

Impaired iron homeostasis may cause damage to dopaminergic neurons and is critically involved in the pathogenesis of Parkinson’s disease. At present, very little is understood about the effect of neonatal iron intake on behavior in aging animals. Therefore, we hypothesized that increased neonatal iron intake would result in signiifcant behavior abnormalities and striatal dopamine depletion during aging, and Sirtuin 2 contributes to the age-related neurotoxicity. In the present study, we observed that neonatal iron intake （120 μg/g per day） during postnatal days 10–17 resulted in significant behavior abnormalities and striatal dopamine depletion in aging rats. Furthermore, after AK-7 （a selective Sirtuin 2 inhibitor） was injected into the substantia nigra at postnatal 540 days and 570 days （5 μg/side per day）, striatal dopamine depletion was signiifcant-ly diminished and behavior abnormality was improved in aging rats with neonatal iron intake. Experimental ifndings suggest that increased neonatal iron intake may result in Parkinson’s dis-ease-like neurochemical and behavioral deifcits with aging, and inhibition of Sirtuin 2 expression may be a neuroprotective measure in Parkinson’s disease.

Salmonella-mediated blood-brain barrier penetration,tumor homing and tumor microenvironment regulation for enhanced chemo/bacterial glioma therapy

Chemotherapy is an important adjuvant treatment of glioma,while the efficacy is far from satisfactory,due not only to the biological barriers of blood-brain barrier(BBB)and blood-tumor barrier(BTB)but also to the intrinsic resistance of glioma cells via multiple survival mechanisms such as upregulation of P-glycoprotein(P-gp).To address these limitations,we report a bacteria-based drug delivery strategy for BBB/BTB transportation,glioma targeting,and chemo-sensitization.Bacteria selectively colonized into hypoxic tumor region and modulated tumor microenvironment,including macrophages repolarization and neutrophils infiltration.Specifically,tumor migration of neutrophils was employed as hitchhiking delivery of doxorubicin(DOX)-loaded bacterial outer membrane vesicles(OMVs/DOX).By virtue of the surface pathogen-associated molecular patterns derived from native bacteria,OMVs/DOX could be selectively recognized by neutrophils,thus facilitating glioma targeted delivery of drug with significantly enhanced tumor accumulation by 18-fold as compared to the classical passive targeting effect.Moreover,the P-gp expression on tumor cells was silenced by bacteria typeⅢsecretion effector to sensitize the efficacy of DOX,resulting in complete tumor eradication with 100%survival of all treated mice.In addition,the colonized bacteria were finally cleared by anti-bacterial activity of DOX to minimize the potential infection risk,and cardiotoxicity of DOX was also avoided,achieving excellent compatibility.This work provides an efficient trans-BBB/BTB drug delivery strategy via cell hitchhiking for enhanced glioma therapy.

Optically transparent graphene-based cognitive metasurface for adaptive frequency manipulation

Optically transparent microwave absorbing metasurfaces have shown great potential and are needed in multiple applications environments containing optical windows owing to their ability to reduce backscattering electromagnetic(EM)signals while keeping continuous optical observation.Meanwhile,they are also required to have adaptive EM manipulation capability to cope with complex and capricious EM environments.As a general approach,distributed circuit components,including positive-intrinsic-negative diodes and varactors and sensing components,are integrated with passive absorbing metasurfaces to realize adaptive control of microwave absorption.However,these circuit elements generally require bulky electrical wires and complex control circuits to regulate the operating state,resulting in the absorbing structures being optically opaque.Hence,it is a great challenge to realize self-operating absorbers while maintaining optical transparency.Here,we report an optically transparent cognitive metasurface made of patterned graphene sandwich structures and a radio frequency detector,which can achieve adaptive frequency manipulation to match incident EM waves.As a proof-of-principle application example,we realize a closed-loop automatic absorber system prototype of the proposed graphene metasurface with self-adaptive frequency variation,without any human intervention.The approach may facilitate other adaptive metadevices in microwave regime with high-level recognition and manipulation and,more generally,promote the development of intelligent stealth technologies.

Enhancing thermal conductivity of silicone rubber composites by insitu constructing SiC networks:A finite-element study based on first principles calculation

Polymer composites as thermal interface materials have been widely used in modern electronic equipment.In this work,we report a novel method to prepare highly through-plane thermally conductive silicone rubber(SR)composites with vertically aligned silicon carbide fibers(VA-SiCFs)entangled by SiC nanowires(SiCNWs)networks.First,a series of carbon fibers(CFs)skeletons were fabricated in sequence of coating poor thermally conductive polyacrylonitrile-based CFs with polydopamine,icetemplated assembly,and freeze-drying processes.Furthermore,VA-SiCFs networks,i.e.,long-range continuous SiCFs-SiCNWs networks,based on the prepared CFs skeletons,were in-situ obtained via template-assisted chemical vapor deposition method.The thermal conductivity enhancement mechanism of VA-SiCFs networks on its SR composites was also intensively studied by finite element simulation,based on the first principles investigation of SiC,and Foygel’s theory.The in-situ grown VA-SiCFs networks possess high intrinsic thermal conductivity without the thermal interface between fillers,acting as the high-efficiency through-plane long-range continuous thermal conduction path,in which the SiCNWs were the in-plane“thermal spreader”.The VA-SiCFs/SR composites reached a high through-plane thermal conductivity,2.13 W/(m·K),at the filler loading of 15 vol.%,which is 868.2%,and 249.2%higher than that of pure SR sample,and random-CFs@polydopamine(PDA)/SR composites at the same content,respectively.The VA-SiCFs/SR composites also exhibited good electrical insulation performance and excellent dimensional stability,which guaranteed the stable interfacial heat transfer of high-power density electronic devices.

A step towards the application of molecular plasmonic-like excitations of PAH derivatives in organic electrochromics

Polycyclic aromatic hydrocarbons(PAHs), are regarded as molecular fragments of graphene and are facilely available through chemical synthesis. Recently, it is found collective charge density oscillations with strong induced electromagnetic field display in PAH derivatives. This phenomenon, analogue to plasmonic excitation in metal, called molecular plasmonics, arise the significant interest of physicists. Instead of discussing its rich physics, this work aims at the application of molecular plasmon-like excitations in electrochromics and optoelectronics. We found that the energy and the intensity of plasmonic-like oscillation could be largely tuned by increasing the conjugation size along both the longitude/transverse axis in PAHs. Besides, the dimeric PAH demonstrates the possibility that molecular plasmonics could be designed using PAHs as building blocks for integration into larger molecular systems. Moreover, this work straightforwardly extends the molecular plasmonic-like property from C–H composed PAHs to much more versatile planar conjugation systems with heteroatoms, achieving transferring between p-type and n-type organic semiconductors. Therefore, with the natural abundance, low cost, easily chemical synthesis of PAH derivatives, we believe this work paves the way for the application of molecular plasmonic-like properties in optoelectronics.

The recommendations of Chinese Parkinson’s disease and movement disorder society consensus on therapeutic management of Parkinson’s disease

Background:Parkinson’s disease(PD)is a chronic,progressive and debilitating disease,which affects over 2.5 million people in China.PD is characterized clinically by resting tremor,muscular rigidity,bradykinesia and postural instability.As the disease progresses,additional complications can arise such as non-motor and neurobehavioral symptoms.Pharmacological treatment and surgical intervention for PD have been implemented in China.Until 10 years ago,there was lack of standardization for the management of PD in different regions and among different physicians,leading to different treatment levels in different regions and different physicians.Since then,the Chinese Parkinson’s Disease and Movement Disorder Society have published three versions of guidelines for the management of PD in China,in 2006,2009 and 2014,respectively.Correspondingly,the overall level of treatment for PD in China improved.Objectives:To update the treatment guidelines based on current foreign and domestic practice guidelines and clinical evidence,and to improve the treatment options available to physicians in the management of PD.Summary:A variety of treatment recommendations in the treatment guidelines have been proposed,including physical activity and disease-modifying medication,which should be initiated at the early-stage of the disease.The principles of dosage titration should be followed to avoid acute adverse reactions to the drugs,to achieve a satisfactory clinical effect with a low dose and to reduce the incidence of long-term motor complications.Moreover,different treatment strategies should be considered at different stages of the disease.Importantly,treatment guidelines and personalized treatments should be valued equally.A set of treatment recommendations has been developed to assist physicians to improve and optimize clinical outcomes for patients with PD in China.

Rock inhibitor may compromise human induced pluripotent stem cells for cardiac differentiation in 3D

Cardiomyocytes differentiated from human induced pluripotent stem cells(iPSCs)are valuable for the understanding/treatment of the deadly heart diseases and their drug screening.However,the very much needed homogeneous 3D cardiac differentiation of human iPSCs is still challenging.Here,it is discovered surprisingly that Rock inhibitor(RI),used ubiquitously to improve the survival/yield of human iPSCs,induces early gastrulation-like change to human iPSCs in 3D culture and may cause their heterogeneous differentiation into all the three germ layers(i.e.,ectoderm,mesoderm,and endoderm)at the commonly used concentration(10μM).This greatly compromises the capacity of human iPSCs for homogeneous 3D cardiac differentiation.By reducing the RI to 1μM for 3D culture,the human iPSCs retain high pluripotency/quality in inner cell mass-like solid 3D spheroids.Consequently,the beating efficiency of 3D cardiac differentiation can be improved to more than 95%in~7 days(compared to less than~50%in 14 days for the 10μM RI condition).Furthermore,the outset beating time(OBT)of all resultant cardiac spheroids(CSs)is synchronized within only 1 day and they form a synchronously beating 3D construct after 5-day culture in gelatin methacrylol(GelMA)hydrogel,showing high homogeneity(in terms of the OBT)in functional maturity of the CSs.Moreover,the resultant cardiomyocytes are of high quality with key functional ultrastructures and highly responsive to cardiac drugs.These discoveries may greatly facilitate the utilization of human iPSCs for understanding and treating heart diseases.

Effects of resource availability on the trade-off between seed and vegetative reproduction

Aims To explore whether the trade-off between seed and vegetative reproductive modes is flexible in environments with different amounts of available resources to maintain optimal behaviors.Methods A transition matrix model was established to determine the optimal trade-off between seed and vegetative reproduction in resources–variable habitats.Important Findings The model predicts that plants allocate more resources to seed reproduction when available resources are scarce.With increasing resources,more vegetative propagules are produced.However,if resources keep increasing to a harmful level,plants would switch to seeds again.

A novel broadband and high-gain microstrip reflectarray antenna with variable polarization

This article proposes a new kind of microstrip reflectarray antenna,of which the polarization could be reconfigured among all the polarization states instead of some fixed states in a dual-or multi-polarized antenna.The mechanism for polarized variability is so simple that only mechanical rotation is needed.Theoretical analysis shows that the reflected polarization covers all states and that the dual-or multi-layered unit structure sandwiched with air-gaps can broaden the bandwidth efficiently.Moreover,it is demonstrated that adopting more elements can enhance antenna gain.With these advantageous features,this kind of antenna has the potential significance for engineering applications in radar,communication,etc.In this article,a complete theoretical analysis as well as a specific design sample is given to verify this method.

A novel ABCD1 G1202A mutation in a Chinese patient with pure adrenomyeloneuropathy and literature review

Adrenomyeloneuropathy(AMN)is a kind of varied disease caused by ABCD1 gene mutation and characterized by very-long-chain fatty acids(VLCFA)accumulation.It is diag-nosed by clinical features,high VLCFAs levels and ABCD1 gene mutation.AMN is rarely reported in Chinese population.In this study,we report the genetic and clinical features of a Chinese pure AMN patient.Meanwhile,we conducted a literature review of AMN cases to summarize the characteristics of AMN.We report a rare Chinese pure AMN case with slowly progressive weakness of the lower extremities,caused by a novel c.1202G>A mutation in ABCD1 gene.The literature review indicates that spastic paraplegia is the mainly clinical manifestation in patients with AMN.VLCFAs and ABCD1 gene test should be performed in patients with spastic paraplegia of the lower limbs to diagnose AMN.