The uniform growth of single-crystal graphene over wafer-scale areas remains a challenge in the commercial-level manufacturability of various electronic, photonic, mechanical, and other devices based ...on graphene. Here, we describe wafer-scale growth of wrinkle-free single-crystal monolayer graphene on silicon wafer using a hydrogen-terminated germanium buffer layer. The anisotropic twofold symmetry of the germanium (110) surface allowed unidirectional alignment of multiple seeds, which were merged to uniform single-crystal graphene with predefined orientation. Furthermore, the weak interaction between graphene and underlying hydrogen-terminated germanium surface enabled the facile etch-free dry transfer of graphene and the recycling of the germanium substrate for continual graphene growth.
Internet addiction has become increasingly recognized as a mental disorder, though its neurobiological basis is unknown. This study used functional neuroimaging to investigate whole-brain functional ...connectivity in adolescents diagnosed with internet addiction. Based on neurobiological changes seen in other addiction related disorders, it was predicted that connectivity disruptions in adolescents with internet addiction would be most prominent in cortico-striatal circuitry.
Participants were 12 adolescents diagnosed with internet addiction and 11 healthy comparison subjects. Resting-state functional magnetic resonance images were acquired, and group differences in brain functional connectivity were analyzed using the network-based statistic. We also analyzed network topology, testing for between-group differences in key graph-based network measures.
Adolescents with internet addiction showed reduced functional connectivity spanning a distributed network. The majority of impaired connections involved cortico-subcortical circuits (∼24% with prefrontal and ∼27% with parietal cortex). Bilateral putamen was the most extensively involved subcortical brain region. No between-group difference was observed in network topological measures, including the clustering coefficient, characteristic path length, or the small-worldness ratio.
Internet addiction is associated with a widespread and significant decrease of functional connectivity in cortico-striatal circuits, in the absence of global changes in brain functional network topology.
A hybrid system with vertical carbon nanotubes (CNTs) grown on reduced graphene films composed of overlapping and reduced graphene oxide platelets is reported. Such carbon hybrid films have excellent ...flexibility and stretchability (see image), can be readily transferred to any substrate including nonplanar surfaces, and were found to have Ohmic electrical contacts throughout all junctions in the CNT/metal‐catalyst/graphene‐film system.
The levels of aspartate aminotransferase (AST/GOT) and alanineaminotransferase (ALT/GPT) in serum can help people diagnose body tissues especially theheart and the liver are injured or not. This ...article provides a comprehensive review ofresearch activities that concentrate on AST/GOT and ALT/GPT detection techniques due totheir clinical importance. The detection techniques include colorimetric, spectrophotometric,chemiluminescence, chromatography, fluorescence and UV absorbance, radiochemical, andelectrochemical techniques. We devote the most attention on experimental principle. Insome methods a few representative devices and important conclusions are presented.
Ischemic white matter injuries underlie cognitive decline in the elderly and vascular dementia. Ischemia in the subcortical white matter is caused by chronic reduction of blood flow due to narrowing ...of small arterioles. However, it remains unclear how chronic ischemia leads to white matter pathology. We aimed to develop an in vitro model of ischemic white matter injury using organotypic slice cultures. Cultured cerebellar slices preserved fully myelinated white matter tracts that were amenable to chronic hypoxic insult. Prolonged hypoxia caused progressive morphological evidence of axonal degeneration with focal constrictions and swellings. In contrast, myelin sheaths and oligodendrocytes exhibited remarkable resilience to hypoxia. The cytoskeletal degradation of axons was accompanied by mitochondrial shortening and lysosomal activation. Multiple pharmacological manipulations revealed that the AMPA glutamate receptor, calpain proteolysis, and lysosomal proteases were independently implicated in hypoxia-induced axonal degeneration in our model. Thus, our in vitro model would be a novel experimental system to explore molecular mechanisms of ischemic white matter injury. Furthermore, we verified that the in vitro assay could be successfully utilized to screen for molecules that can ameliorate hypoxia/ischemia-induced axonal degeneration.
Display omitted
•We established cultured cerebellar slice model to examine effects of chronic hypoxia on myelinated white matter track.•Prolonged hypoxia resulted in prominent axonal degeneration, while compact myelin and oligodendrocytes were spared.•AMPA receptor, calpain, and lysosomal proteases were independently implicated in hypoxia-induced axonal degeneration.•Our in vitro model could be utilized for screening therapeutic agents targeting ischemic white matter degeneration.
•Attachment security is detected as a different brain activity in typically developing children.•The quality of attachment configures the approach and avoidance motivational system in our ...brain.•Striatum, strongly linked to reward and motivational processing, showed the largest effects.
This study investigated neural correlates of children’s attachment security using functional magnetic resonance imaging. Fifty-one boys’ attachment styles (age mean = 9.5 years, SD = 0.61) were assessed with the Separation Anxiety Test (SAT). We created an fMRI version of the SAT to activate children’s attachment system in fMRI environment and contrasted two conditions in which children were instructed to infer the specific feeling of the boy in the picture or to identify objects or physical activities. In the final fMRI analysis (N = 21), attachment security could be detected at the neural level corresponding to the behavioural differences in the attachment interview. Securely attached children showed greater activation in the frontal, limbic and basal ganglia area which included the dorsolateral prefrontal cortex, amygdala, cingulate cortex and striatum, compared to other children who had lower quality of attachment. These regions have a key role in socio-emotional information processing and also represent a brain network related to approach and avoidance motivation in humans. Especially the striatum, strongly linked to reward processing underpinning social approach and avoidance motivation, showed the largest effects in these differences and also positively correlated with emotional openness scores in SAT. This suggests that the quality of attachment configures the approach and avoidance motivational system in our brain mediated by the striatum.
Dye‐sensitized solar cells (DSSCs) comprising chemically synthesized nanorods and nanoparticles are investigated. In identical circumstances, except for the charge‐collection efficiency, ...nanorod‐based DSSCs show improved photovoltaic properties (6.2 % versus 4.3 % for NP‐based DSSCs) owing to the characteristics of slightly enhanced electron transport and predominantly degraded charge recombination, compared with nanoparticle‐based DSSC.
The present study reports the influence of pre-carbonization on the properties of KOH-activated coal tar pitch (CTP). The change of crystallinity and pore structure of pre-carbonized CTPs as well as ...their activated carbons (ACs) as function of pre-carbonization temperature are investigated. The crystallinity of pre-carbonized CTPs increases with increasing the carbonization temperature up to 600°C, but a disorder occurs during the carbonization around 700°C and an order happens gradually with increasing the carbonization temperatures in range of 800–1000°C. The CTPs pre-carbonized at high temperatures are more difficult to be activated with KOH than those pre-carbonized at low temperatures due to the increase of micro-crystalline size and the decrease of surface functional groups. The micro-pores and meso-pores are well developed at around 1.0nm and 2.4nm, respectively, as the ACs are pre-carbonized at temperatures of 500–600°C, exhibiting high specific capacitances as electrode materials for electric double layer capacitor (EDLC). Although the specific surface area (SSA) and pore volume of ACs pre-carbonized at temperatures of 900–1000°C are extraordinary low (non-porous) as compared to those of AC pre-carbonized at 600°C, their specific capacitances are comparable to each other. The large specific capacitances with low SSA ACs can be attributed to the structural change resulting from the electrochemical activation during the 1st charge above 2.0V.
•Preparation of activated carbons from coal tar pitch precursors.•Control of porous texture by pre-carbonization temperature.•Structural difference of precursor leads to improvement of electrochemical property.•Non-porous texture but comparable capacitance by an electrochemical activation.
This paper presents a teleoperation system of robot grasping for undefined objects based on a real-time EEG (Electroencephalography) measurement and shared autonomy. When grasping an undefined object ...in an unstructured environment, real-time human decision is necessary since fully autonomous grasping may not handle uncertain situations. The proposed system allows involvement of a wide range of human decisions throughout the entire grasping procedure, including 3D movement of the gripper, selecting proper grasping posture, and adjusting the amount of grip force. These multiple decision-making procedures of the human operator have been implemented with six flickering blocks for steady-state visually evoked potentials (SSVEP) by dividing the grasping task into predefined substeps. Each substep consists of approaching the object, selecting posture and grip force, grasping, transporting to the desired position, and releasing. The graphical user interface (GUI) displays the current substep and simple symbols beside each flickering block for quick understanding. The tele-grasping of various objects by using real-time human decisions of selecting among four possible postures and three levels of grip force has been demonstrated. This system can be adapted to other sequential EEG-controlled teleoperation tasks that require complex human decisions.
The Wnt/β-catenin pathway plays important roles in the differentiation of multiple cell types, including mesenchy- mal stem cells. Using a cell-based chemical screening assay with a synthetic ...chemical library of 270 000 compounds, we identified the compound SKL2001 as a novel agonist of the Wnt/β-catenin pathway and uncovered its molecu- lar mechanism of action. SKL2001 upregulated p-catenin responsive transcription by increasing the intracellular β-catenin protein level and inhibited the phosphorylation of β-catenin at residues Ser33/37/Thr41 and Ser45, which would mark it for proteasomal degradation, without affecting CK1 and GSK-315 enzyme activities. Biochemical anal- ysis revealed that SKL2001 disrupted the Axin/β-catenin interaction, which is a critical step for CK1- and GSK-3β- mediated phosphorylation of β-catenin at Ser33/37/Thr41 and Ser45. The treatment of mesenchymal stem cells with SKL2001 promoted osteoblastogenesis and suppressed adipocyte differentiation, both of which were accompanied by the activation of Wnt/β-catenin pathway. Our findings provide a new strategy to regulate mesenchymal stem cell dif- ferentiation by modulation of the Wntβ-catenin pathway.
PDF
