59 research outputs found
Axonal Fiber Terminations Concentrate on Gyri
Convoluted cortical folding and neuronal wiring are 2 prominent attributes of the mammalian brain. However, the macroscale intrinsic relationship between these 2 general cross-species attributes, as well as the underlying principles that sculpt the architecture of the cerebral cortex, remains unclear. Here, we show that the axonal fibers connected to gyri are significantly denser than those connected to sulci. In human, chimpanzee, and macaque brains, a dominant fraction of axonal fibers were found to be connected to the gyri. This finding has been replicated in a range of mammalian brains via diffusion tensor imaging and high–angular resolution diffusion imaging. These results may have shed some lights on fundamental mechanisms for development and organization of the cerebral cortex, suggesting that axonal pushing is a mechanism of cortical folding
Serum Starvation Induced Cell Cycle Synchronization Facilitates Human Somatic Cells Reprogramming
Human induced pluripotent stem cells (iPSCs) provide a valuable model for regenerative medicine and human disease research. To date, however, the reprogramming efficiency of human adult cells is still low. Recent studies have revealed that cell cycle is a key parameter driving epigenetic reprogramming to pluripotency. As is well known, retroviruses such as the Moloney murine leukemia virus (MoMLV) require cell division to integrate into the host genome and replicate, whereas the target primary cells for reprogramming are a mixture of several cell types with different cell cycle rhythms. Whether cell cycle synchronization has potential effect on retrovirus induced reprogramming has not been detailed. In this study, utilizing transient serum starvation induced synchronization, we demonstrated that starvation generated a reversible cell cycle arrest and synchronously progressed through G2/M phase after release, substantially improving retroviral infection efficiency. Interestingly, synchronized human dermal fibroblasts (HDF) and adipose stem cells (ASC) exhibited more homogenous epithelial morphology than normal FBS control after infection, and the expression of epithelial markers such as E-cadherin and Epcam were strongly activated. Futhermore, synchronization treatment ultimately improved Nanog positive clones, achieved a 15–20 fold increase. These results suggested that cell cycle synchronization promotes the mesenchymal to epithelial transition (MET) and facilitates retrovirus mediated reprogramming. Our study, utilization of serum starvation rather than additional chemicals, provide a new insight into cell cycle regulation and induced reprogramming of human cells
APPLICATION OF STOCHASTIC PROGRAMMING IN SCUC
This thesis presents a scenario-reduction technique to solve stochastic security- constrained unit commitment (Stochastic SCUC) problems. The uncertainty of wind power generation is simulated by the Monte Carlo (MC) method. The Stochastic SCUC problem is formulated as a mixed-integer linear programming (MIP) problem and the large-scale optimization problem is decomposed into one master problem and several tractable subproblems for each scenario. Computational burdens for solving scenarios-based Stochastic SCUC are mainly depend on the number of scenarios and a scenario-reduction technique is applied to reduce the computation burdens. The numerical results of a 6-bus system show the effectiveness of the Scenarios-Reduction Techniques for solving the Stochastic SCUC problem. Index Terms—Power System Operation, Stochastic Programming, Stochastic SCUC, Monte Carlo Stimulation, Scenarios Reduction.M.S. in Electrical Engineering, May 201
An automated management system for the community health service in China
Objective: To explore a useful tool for health administrative departments to manage the community health service (CHS). Methods: On the basis of existing health laws and regulations in China, we describe the design of an automated management system for the CHS with a supervision system and an evaluation system using computer technology and corresponding design software. Results: Four changes to the management of the CHS were made: repetitive work became automated, complicated work became simplified, nonregular services decreased, and obscure instructions became clear and specific. Conclusion: The automated management system will promote the development of CHS management
Transcriptome Analyses Reveal Lipid Metabolic Process in Liver Related to the Difference of Carcass Fat Content in Rainbow Trout (Oncorhynchus mykiss)
Excessive accumulation of carcass fat in farm animals, including fish, has a significant impact on meat quality and on the cost of feeding. Similar to farmed animals and humans, the liver can be considered one of the most important organs involved in lipid metabolism in rainbow trout (Oncorhynchus mykiss). RNA-seq based whole transcriptome sequencing was performed to liver tissue of rainbow trout with high and low carcass fat content in this study. In total 1,694 differentially expressed transcripts were identified, including many genes involved in lipid metabolism, such as L-FABP, adiponectin, PPAR-α, PPAR-β, and IGFBP1a. Evidence presented in this study indicated that lipid metabolic process in liver may be related to the difference of carcass fat content. The relevance of PPAR-α and PPAR-β as molecular markers for fat storage in liver should be worthy of further investigation
Interfacial Hydroxyl Promotes the Reduction of 4 Nitrophenol by Ag-Based Catalysts Confined in Dendritic Mesoporous Silica Nanospheres
Surface states—the electronic states emerging as a solid material terminates at a surface—are usually vulnerable to contaminations and defects. This fundamental limitation has prohibited systematic studies of the potential role of surface states in surface reactions and catalysis, especially in more realistic environments. We use the selective reduction of 4-Nitrophenol on silver-covered dendritic mesoporous silica nanospheres (DMSNs) as a prototype example, and show that the dynamic intermediate surface states (DISS) spatially formed by spin orbital coupling (SOC) in singly hydrated hydroxyl complex can significantly enhance the adsorption energy of both 4-Nitrophenol and BH4- anions, by promoting different directions of static electron transfer. The concept of DISS as an electron bath may lead to new design principles beyond the conventional d-band theory of heterogeneous catalysis
Endothelin-1 Activation of the Endothelin B Receptor Modulates Pulmonary Endothelial CX3CL1 and Contributes to Pulmonary Angiogenesis in Experimental Hepatopulmonary Syndrome
Hepatic production and release of endothelin-1 (ET-1) binding to endothelin B (ETB) receptors, overexpressed in the lung microvasculature, is associated with accumulation of pro-angiogenic monocytes and vascular remodeling in experimental hepatopulmonary syndrome (HPS) after common bile duct ligation (CBDL). We have recently found that lung vascular monocyte adhesion and angiogenesis in HPS involve interaction of endothelial C-X3-C motif ligand 1 (CX3CL1) with monocyte CX3C chemokine receptor 1 (CX3CR1), although whether ET-1/ETB receptor activation influences these events is unknown. Our aim was to define if ET-1/ETB receptor activation modulates CX3CL1/CX3CR1 signaling and lung angiogenesis in experimental HPS. A selective ETB receptor antagonist, BQ788, was given for 2 weeks to 1-week CBDL rats. ET-1 (±BQ788) was given to cultured rat pulmonary microvascular endothelial cells overexpressing ETB receptors. BQ788 treatment significantly decreased lung angiogenesis, monocyte accumulation, and CX3CL1 levels after CBDL. ET-1 treatment significantly induced CX3CL1 production in lung microvascular endothelial cells, which was blocked by inhibitors of Ca2+ and mitogen-activated protein kinase (MEK)/ERK pathways. ET-1–induced ERK activation was Ca2+ independent. ET-1 administration also increased endothelial tube formation in vitro, which was inhibited by BQ788 or by blocking Ca2+ and MEK/ERK activation. CX3CR1 neutralizing antibody partially inhibited ET-1 effects on tube formation. These findings identify a novel mechanistic interaction between the ET-1/ETB receptor axis and CX3CL1/CX3CR1 in mediating pulmonary angiogenesis and vascular monocyte accumulation in experimental HPS
Surface Electronic State Mediates Proton Transfer at Metal Nanoscale Interface for Catalytic Hydride Reduction of −NO2 to −NH2
Concerted electron and proton transfer is a key step for the reversible conversion of molecular hydrogen in both heterogeneous nanocatalysis and metalloenzyme catalysis. (Gabor A. Somorjai, et al. PNAS, 2016, 113, 5159–5166) However, the activation mechanism involving electron and proton transfer dynamic remains elusive. (Starla D. Glover and Leif Hammarström et al., J. Am. Chem. Soc. 2021, 143, 560−576.) With the most widely used catalytic hydride reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as a model reaction, we evaluate the catalytic activity of noble metal NPs trapped in porous silica in aqueous NaBH4 solution. By virtue of a novel combination of catalyst design, reaction kinetics, isotope labeling, and multiple spectroscopic techniques, we counter-intuitively demonstrates that, the hydrogen resource of the final product of 4-AP by hydride reduction is not originated from the NaBH4 reduced, and that metal NPs (Ag/Pt/Pd) is not a real catalytic active site for surface electron mediation. (Avelino Corma etal., Angew. Chem. Int. Ed. 2007, 46, 7266 –7269; ACS Catal. 2015, 5, 7114−7121.). A completely new ‘Surface Electronic State Mediated Proton Transfer’ mechanism was proposed to understand the catalytic hydride reduction of −NO2 to −NH2 at metal nanoscale interface. The similar concerted electron and proton transfer dynamic was only recently observed in the [FeFe]-hydrogenases for reversible proton reduction. (Gregory A. Voth et al., J. Phys. Chem. B 2013, 117, 4062−4071; J. Chem. Phys. 2014, 141, 22D527; Juan C. Fontecilla-Camps et al., Chem. Rev. 2007, 107, 4273-4303.) We believed that current research provide a completely new insights into the working mechanism of nanocatalysis and metalloenzyme catalysis involved by electron and proton transfer
Topological Excitation of Singly Hydrated Hydroxide Complex in Confined Sub-Nanospace for Bright Color Emission and Heterogeneous Catalysis
This
excellent story answered two unresolved questions in the past one century and
two centuries. The first one is that water is colored or noncolored (Water
as an Activator of Luminescence. Nature 1930, 125, 706-707)? If it is colorful,
why and how does it emit the bright colors? The second question is on the
physical origin of catalysis or catalyst, i.e., the mysterious internal force
of catalysis is what, and how this powerful force determines the chemical
reactivity, including activity, selectivity and life times (or stability of
catalyst)? (A Brief History of Catalysis. CATTECH 2003, 7 (4), 130-138.)
After reading this
interesting story, both seemingly non-related two questions could be perfectly
answered by topological excitation of singly hydrated hydroxide complex in
confined sub-nanospace
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