Malondialdehyde Suppresses Cerebral Function by Breaking Homeostasis between Excitation and Inhibition in Turtle Trachemys scripta

The levels of malondialdehyde (MDA) are high in the brain during carbonyl stress, such as following daily activities and sleep deprivation. To examine our hypothesis that MDA is one of the major substances in the brain leading to fatigue, the influences of MDA on brain functions and neuronal encodings in red-eared turtle (Trachemys scripta) were studied. The intrathecal injections of MDA brought about sleep-like EEG and fatigue-like behaviors in a dose-dependent manner. These changes were found associated with the deterioration of encoding action potentials in cortical neurons. In addition, MDA increased the ratio of γ-aminobutyric acid to glutamate in turtle's brain, as well as the sensitivity of GABAergic neurons to inputs compared to excitatory neurons. Therefore, MDA, as a metabolic product in the brain, may weaken cerebral function during carbonyl stress through breaking the homeostasis between excitatory and inhibitory neurons

Extraction of Pleurotus ostreatus Protein by the Aqueous Two-phase System and Its Characterization

To achieve green and efficient extraction of Pleurotus ostreatus protein (PP), the phase diagram of the PEG-(NH4)2SO4 aqueous two-phase system (ATPS) was constructed using the cloud point method. Protein extraction concentration was utilized as evaluation indicator to investigate the effects of ATPS factors such as the molecular weight and mass fraction of PEG, mass fraction of (NH4)2SO4, and proportion of added crude PP extraction. Furthermore, the basic components of PP including emulsification characteristics, foaming properties, and water and oil holding capacities were explored. The optimal process conditions for PP extraction were determined using response surface methodology, with PEG2000 mass fraction set at 19.5%, (NH4)2SO4 mass fraction at 22.6%, and protein crude extract mass fraction at 26%. Under these conditions, the extraction rate of protein reached 93.16%, with a protein content of 1.71 mg/mL. Analysis of the physical and chemical properties revealed uniform protein composition with an average particle size of approximately 220.2 nm. The total amino acid content was measured at 221.46 mg/g, with the highest aspartic acid (Asp) content at 25.06 mg/g. Moreover, PP exhibited exceptional emulsification stability 65.22%, foaming properties 79.87%, and water holding capacity 2.61±0.18 g/g. Compared with similar food proteins, PP protein had higher emulsifying stability, foaming ability, and water holding capacity. This study used a green, environmentally friendly, and low toxicity aqueous two-phase method to extract PP protein, providing a new approach for the green and sustainable development of protein extraction in the food industry, and a research foundation for the development of functional foods based on PP protein

Noninvasive Evaluation of Injectable Chitosan/Nano-Hydroxyapatite/Collagen Scaffold via Ultrasound

To meet the challenges of designing an in situ forming scaffold and regenerating bone with complex three-dimensional (3D) structures, an in situ forming hydrogel scaffold based on nano-hydroxyapatite (nHA), collagen (Col), and chitosan (CS) was synthesized. Currently, only a limited number of techniques are available to mediate and visualize the injection process of the injectable biomaterials directly and noninvasively. In this study, the potential of ultrasound for the quantitative in vivo evaluation of tissue development in CS/nHAC scaffold was evaluated. The CS/nHAC scaffold was injected into rat subcutaneous tissue and evaluated for 28 days. Quantitative measurements of the gray-scale value, volume, and blood flow of the scaffold were evaluated using diagnostic technique. This study demonstrates that ultrasound can be used to noninvasively and nondestructively monitor and evaluate the in vivo characteristics of injectable bone scaffold. In comparison to the CS, the CS/nHAC scaffold showed a greater stiffness, less degradation rate, and better blood supply in the in vivo evaluation. In conclusion, the diagnostic ultrasound method is a good tool to evaluate the in vivo formation of injectable bone scaffolds and facilitates the broad use to monitor tissue development and remodeling in bone tissue engineering

The Changes of Intrinsic Excitability of Pyramidal Neurons in Anterior Cingulate Cortex in Neuropathic Pain

To find satisfactory treatment strategies for neuropathic pain syndromes, the cellular mechanisms should be illuminated. Central sensitization is a generator of pain hypersensitivity, and is mainly reflected in neuronal hyperexcitability in pain pathway. Neuronal excitability depends on two components, the synaptic inputs and the intrinsic excitability. Previous studies have focused on the synaptic plasticity in different forms of pain. But little is known about the changes of neuronal intrinsic excitability in neuropathic pain. To address this question, whole-cell patch clamp recordings were performed to study the synaptic transmission and neuronal intrinsic excitability 1 week after spared nerve injury (SNI) or sham operation in male C57BL/6J mice. We found increased spontaneous excitatory postsynaptic currents (sEPSC) frequency in layer II/III pyramidal neurons of anterior cingulate cortex (ACC) from mice with neuropathic pain. Elevated intrinsic excitability of these neurons after nerve injury was also picked up, which was reflected in gain of input-output curve, inter-spike interval (ISI), spike threshold and Refractory period (RP). Besides firing rate related to neuronal intrinsic excitability, spike timing also plays an important role in neural information processing. The precision of spike timing measured by standard deviation of spike timing (SDST) was decreased in neuropathic pain state. The electrophysiological studies revealed the elevated intrinsic excitation in layer II/III pyramidal neurons of ACC in mice with neuropathic pain, which might contribute to central excitation

Highly stretchable conductor inspired by compliant mechanism

Flexible and stretchable conductors have invaluable applications in multiple domains, such as sensors, displays, and electronic skins. The stable conductance exhibited by conductors when subjected to diverse forms of deformation, such as tensile stress, curvature, or torsion, represents a fundamental characteristic. Attaining high conductivity and stretchability simultaneously in conductive materials is a formidable challenge, owing to inherent constraints in materials found in nature. To overcome this problem, an innovative approach of structurally designing conductors using existing materials to achieve high deformability and stretchability, i.e. stretchable conductors inspired by a compliant mechanism is proposed in this paper. Thus, a novel stretchable conductor inspired by flexible mechanisms is introduced. Unlike stretchable conductors based on Kirigami structures, the stretchable conductor based on flexible mechanisms can achieve large in‐plane deformation within the material's strength limit. The concept and design process of the highly deformable stretchable conductor inspired by flexible mechanisms are presented in this paper. Experimental results show that the resistance change ratio of the conductor remains within 0.05% during the 0–200% strain process. The consistency and durability of the conductor during stretching deformation are also confirmed through 500 repetitions of the test. Additionally, the experiments with the electric motor and light‐emitting diode (LED) light confirm the conductor's ability to maintain a stable current

Mesenchymal stromal cells’ therapy for polyglutamine disorders: where do we stand and where should we go?

Polyglutamine (polyQ) diseases are a group of inherited neurodegenerative disorders caused by the expansion of the cytosine-adenine-guanine (CAG) repeat. This mutation encodes extended glutamine (Q) tract in the disease protein, resulting in the alteration of its conformation/physiological role and in the formation of toxic fragments/aggregates of the protein. This group of heterogeneous disorders shares common molecular mechanisms, which opens the possibility to develop a pan therapeutic approach. Vast efforts have been made to develop strategies to alleviate disease symptoms. Nonetheless, there is still no therapy that can cure or effectively delay disease progression of any of these disorders. Mesenchymal stromal cells (MSC) are promising tools for the treatment of polyQ disorders, promoting protection, tissue regeneration, and/or modulation of the immune system in animal models. Accordingly, data collected from clinical trials have so far demonstrated that transplantation of MSC is safe and delays the progression of some polyQ disorders for some time. However, to achieve sustained phenotypic amelioration in clinics, several treatments may be necessary. Therefore, efforts to develop new strategies to improve MSC's therapeutic outcomes have been emerging. In this review article, we discuss the current treatments and strategies used to reduce polyQ symptoms and major pre-clinical and clinical achievements obtained with MSC transplantation as well as remaining flaws that need to be overcome. The requirement to cross the blood-brain-barrier (BBB), together with a short rate of cell engraftment in the lesioned area and low survival of MSC in a pathophysiological context upon transplantation may contribute to the transient therapeutic effects. We also review methods like pre-conditioning or genetic engineering of MSC that can be used to increase MSC survival in vivo, cellular-free approaches-i.e., MSC-conditioned medium (CM) or MSC-derived extracellular vesicles (EVs) as a way of possibly replacing the use of MSC and methods required to standardize the potential of MSC/MSC-derived products. These are fundamental questions that need to be addressed to obtain maximum MSC performance in polyQ diseases and therefore increase clinical benefits.Portuguese Foundation for Science and Technology: SFRH/BD/148877/2019; CENTRO01-0145-FEDER-000008 CENTRO-01-0145FEDER-022095 POCI-01-0145-FEDER-016719 POCI-01-0145-FEDER-029716 POCI01-0145-FEDER-016807 POCI-01-0145-FEDER016390 UID4950/2020 CENTRO-01-0145-FEDER-022118info:eu-repo/semantics/publishedVersio

Characterization of MOCVD-grown non-stoichiometric SiNx

The surface morphologies and X-ray photoelectron spectra of MOCVD-grown SiNx were investigated. Highly Si-rich SiNx nanoislands not fully covering the sapphire surface were observed for SiNx deposition at low temperature (545 degrees C) with NH3/SiH4 flow rate of 2500/40 sccm. The surface roughness decreased from 0.91 nm to 0.23 nm with the reduction of SiH4 flow rate from 40 sccm to 3 sccm. The reduction of the SiH4 flow rate did not cause a linear decrease of SiN ratio, which indicated that the SiH4 Supply Was saturated when the NH3 supply was 2500 sccm and deposition temperature was fixed at 545 degrees C. Relatively "thick" SiNx layers with stoichiometry close to 1 were formed for SiNx deposition at high temperature due to high decomposition rate of ammonia and high reaction rate between silane and ammonia. The SiNx layers almost fully covered the sapphire surface and showed surface structures of both nanoislands and nanoholes. By employing the same NH3/SiH4 flow rate of 2500/40 sccm the surface roughness of SiNx layers decreased from 0.91 nm to 0.17 nm with the increase of deposition temperature from 545 degrees C to 1035 degrees C. Saturated pre-nitridation would likely cause surface roughening. (C) 2008 Elsevier B.V. All rights reserved

Significant increase of light emission efficiency by in situ site-selective etching of InGaN quantum wells

Natural Science Foundation of China [60876008]An indium post-treatment of the InGaN epilayers was employed for InGaN-to-GaN interface modification. We find that the treatment could lead to selective etching of the InGaN epilayers around threading dislocations (TDs) due to preferential etching of the chemically active step-correlated TDs and formation of indium-rich InGaN nanostructures on the smooth InGaN surface. The intentionally formed V-shaped pits by site-selective etching of the InGaN epilayers resulted in an increased surface potential barrier at the pit sidewalls due to the relatively thin InGaN single quantum well. The increased energy bandgap of the InGaN active layers around the TDs cores caused the lateral carrier confinement away from nonradiative recombination at the defects and thus significantly enhanced the light emission efficiency. (c) 2009 American Institute of Physics. [DOI: 10.1063/1.3176931