Optimizing the optical and magneto-optical response of all-dielectric metasurfaces with tilted side walls.

All-dielectric metasurfaces based on ferrimagnetic iron garnets are a promising platform for realizing ultra-compact magneto-optical (MO) devices with low loss. However, ferrimagnetic iron garnets are notorious for being intractable on fine nanopatterning, hindering the faithful fabrication of designed nanostructures. In this regard, it is important to assess the influence of fabrication imperfections on the performance of MO metasurfaces. Here, we investigate the optical properties of a MO metasurface with structural imperfections. As the most typical fabrication error, we studied the impact of the tilted side walls of cylindrical garnet disks that constitute the metasurfaces. We found that tilting the side walls drastically degrades the MO response and light transmittance of the device. Nevertheless, it was also found that the performance can be recovered by optimizing the refractive index of the material covering the upper half of the nanodisks.

Spider-Silk-Inspired Nanocomposite Polymers for Durable Daytime Radiative Cooling.

Passive daytime radiative cooling (PDRC) materials, that strongly reflect sunlight and emit thermal radiation to outer space, demonstrate great potential in energy-saving for sustainable development. Particularly, polymer-based PDRC materials, with advantages of easy-processing, low cost, and outstanding cooling performance, have attracted intense attention. However, just like other polymer devices (for example polymer solar cells) working under sunlight, the issue of durability related to mechanical and UV properties needs to be addressed for large-scale practical applications. Here, a spider-silk-inspired design of nanocomposite polymers with potassium titanate (K2 Ti6 O13 ) nanofiber dopants is proposed for enhancing the durability without compromising their cooling performance. The formed tough interface of nanofiber/polymer effectively disperses stress, enhancing the mechanical properties of the polymer matrix; while the K2 Ti6 O13 can absorb high-energy UV photons and transform them into less harmful heat, thereby improving the UV stabilities. Taking poly(ethylene oxide) radiative cooler as an example for demonstration, its Young's modulus and UV resistance increase by 7 and 12 times, respectively. Consequently, the solar reflectance of nanocomposite poly(ethylene oxide) is maintained as constant in a continuous aging test for 720 h under outdoor sunlight. The work provides a general strategy to simultaneously enhance both the mechanical stability and the UV durability of polymer-based PDRC materials toward large-scale applications.

Effects of Pelleted and Extruded Feed on Growth Performance, Intestinal Histology and Microbiota of Juvenile Red Swamp Crayfish (Procambarus clarkii).

The study was conducted to evaluate the extruded and pelleting feed production on growth performance, intestinal histology and microbiome analysis of juvenile red swamp crayfish, Procambarus clarkii. Crayfish were fed either pelleted or extruded feeds that were made using the same formula. Crayfish fed extruded feed had a lower feed conversion ratio, as well as significantly higher levels of trypsin and amylase (p < 0.05) than those fed pelleted feed. However, other growth indices and the activity of lipase were not significantly influenced by the feed processing technique (p > 0.05). In comparison with the pelleted feed group, the lamina propria thickness of crayfish fed extruded feed was significantly lower (p < 0.05). Additionally, the abundance of intestinal microbiota in the extruded feed group was higher than that in the pelleted feed group. The dominant phyla in the intestine of both groups were Proteobacteria, Tenericutes, and Firmicutes, and the relative abundance of Proteobacteria in the extruded feed group was significantly higher than that in the pelleted feed group (p < 0.05). These results revealed that P. clarkii fed extruded feed had higher feed utilization and better intestinal health.

A Retrospective Study of 268 Patients with SARS-CoV-2 Infection to Evaluate the Association Between Blood Glucose and Severity of COVID-19 Pneumonia and Patient Mortality.

BACKGROUND Diabetes is one of the most commonly reported comorbidities among patients infected with SARS-CoV-2. This retrospective study of patients with SARS-CoV-2 infection was conducted to evaluate the association between blood glucose levels and the severity of COVID-19 pneumonia and patient mortality. MATERIAL AND METHODS A total of 268 patients with confirmed SARS-CoV-2 infection were included in this retrospective study. We obtained demographic characteristics, clinical symptoms, laboratory data, and survival information from patients' electronic medical records. Blood glucose was measured on admission to the hospital. Comorbidities, including hypertension, diabetes, chronic kidney disease, chronic liver disease, chronic obstructive pulmonary disease, and cardiovascular disease, were collected by self-reported medical history. RESULTS Significantly higher risks of severe COVID-19 were found in patients with blood glucose levels ranging from 5.53 to 7.27 mmol/L (odds ratio [OR], 3.98; 95% confidence interval [CI], 1.81-8.75) and in patients with blood glucose ≥7.27 mmol/L (OR, 12.10; 95% CI, 5.53-26.48) than in those with blood glucose <5.53 mmol/L. There was a trend toward better survival in patients with blood glucose <5.53 mmol/L than in patients with blood glucose from 5.53 to 7.27 mmol/L (hazard ratio [HR], 6.34; 95% CI, 1.45-27.71) and ≥7.27 mmol/L (HR, 19.37; 95% CI, 4.68-80.17). Estimated 10-day overall survival rates were 96.8%, 90.6%, and 69.3% in patients with blood glucose <5.53 mmol/L, 5.53 to 7.27 mmol/L, and ³7.27 mmol/L, respectively. CONCLUSIONS Hyperglycemia was association with severity of COVID-19 pneumonia and with increased patient mortality. These findings support the need for blood glucose monitoring and control of hyperglycemia in patients with COVID-19 pneumonia.

Two novel nomograms based on inflammatory cytokines or lymphocyte subsets to differentially diagnose severe or critical and Non-Severe COVID-19.

We intend to evaluate the differences of the clinical characteristics, cytokine profiles and immunological features in patients with different severity of COVID-19, and to develop novel nomograms based on inflammatory cytokines or lymphocyte subsets for the differential diagnostics for severe or critical and non-severe COVID-19 patients. We retrospectively studied 254 COVID-19 patients, 90 of whom were severe or critical patients and 164 were non-severe patients. Severe or critical patients had significantly higher levels of inflammatory cytokines than non-severe patients as well as lower levels of lymphocyte subsets. Significantly positive correlations between cytokine profiles were observed, while they were all significantly negatively correlated with lymphocyte subsets. Two effective nomograms were developed according to two multivariable logistic regression cox models based on inflammatory cytokine profiles and lymphocyte subsets separately. The areas under the receiver operating characteristics of two nomograms were 0.834 (95% CI: 0.779-0.888) and 0.841 (95% CI: 0.756-0.925). The bootstrapped-concordance indexes of two nomograms were 0.834 and 0.841 in training set, and 0.860 and 0.852 in validation set. Calibration curves and decision curve analyses demonstrated that the nomograms were well calibrated and had significantly more clinical net benefits. Our novel nomograms can accurately predict disease severity of COVID-19, which may facilitate the identification of severe or critical patients and assist physicians in making optimized treatment suggestions.

Peripheral Inflammatory Cytokines and Lymphocyte Subset Features of Deceased COVID-19 Patients.

OBJECTIVE: To compare the difference of inflammatory cytokines and lymphocyte subsets between deceased patients and survivors with COVID-19. METHODS: This retrospective study included 254 confirmed patients from 10 January to 11 March, 2020, at Tongji Hospital of Wuhan, China. Laboratory and immunologic features were collected and analyzed, and the main outcomes focused on inflammatory cytokines and lymphocyte subsets. RESULTS: A trend of markedly higher levels of inflammatory cytokines as well as lower lymphocyte subset levels in deceased patients was observed compared with survivors. ROC curve analyses indicated that inflammatory cytokines and the decrease levels of T cell, Th (helper T cells) cell, Ts (suppressor T cells) cell, B cell, and NK cell along with Th/Ts ratio increase could be used to predict the death of COVID-19. Multivariate analyses showed that higher levels of IL-6, IL-8, and IL-10 remained significantly correlated with shorter survival time and that the amount of Ts cells was negatively associated with the possibility of death in COVID-19 patients. In conclusion, SARS-CoV-2 would cause lymphopenia and result in decreased lymphocyte subset cells, particularly in Ts cell counts, which further induces hyperinflammatory response and cytokine storm. IL-6, IL-8, IL-10, and Ts cell might be independent predictors for the poor outcome of COVID-19.

Planar hot-electron photodetector utilizing high refractive index MoS2 in Fabry-Pérot perfect absorber.

Hot electron photodetection (HEPD) excited by surface plasmon can circumvent bandgap limitations, opening pathways for additional energy harvesting. However, the costly and time-consuming lithography has long been a barrier for large-area and mass production of HEPD. In this paper, we proposed a planar and electron beam lithography-free hot electron photodetector based on the Fabry-Pérot (F-P) resonance composed of Au/MoS2/Au cavity. The hot electron photodetector has a nanoscale thickness, high spectral tunability, and multicolour photoresponse in the near-infrared region due to the increased round-trip phase shift by using high refractive index MoS2. We predict that the photoresponsivity can achieve up to 23.6 mA W-1 when double cavities are integrated with the F-P cavity. The proposed hot electron photodetector that has a nanoscale thickness and planar stacking is a perfect candidate for large-area and mass production of HEPD.

An ultrathin MoSe2 photodetector with near-perfect absorption.

An ultrathin near-perfect MoSe2 absorber working in the visible regime is demonstrated theoretically and experimentally, and it consists of a MoSe2/Au bi-layer film. The polymer-assisted deposition method is used to synthesize MoSe2 films, which can reduce the roughness and thus improve the film absorption. Simulation results show that the absorption of the absorber with 22 nm MoSe2 reaches to larger than 90% between 628.5 nm and 718 nm with a peak value up to 99.5% at 686 nm. Moreover, the measured absorption also shows near-perfect absorption of this simple absorber. Finally, an ultrathin photodetector is fabricated based on this perfect absorber and shows on/off reproducibility and remarkable photocurrent, which is three orders of magnitude higher than the dark current.

LncRNA MEG3 inhibits HMEC-1 cells growth, migration and tube formation via sponging miR-147.

Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3) has been identified as a regulatory molecule in angiogenesis. The goal of this study was to illustrate how MEG3 affects the angiogenesis of vascular endothelial cells. Expression of MEG3, miR-147 and intracellular cell adhesion molecule-1 (ICAM-1) in human microvascular endothelial cell line (HMEC-1) was altered by transfection, then cell viability, apoptosis, migration, tube formation, as well as the correlation among MEG3, miR-147 and ICAM-1 were explored. MEG3 was down-regulated during tube formation of HMEC-1 cells. MEG3 expression suppressed cells viability, migration and tube formation, while it induced apoptosis. MEG3 could bind with miR-147 and repress miR-147 expression. MiR-147 induced ICAM-1 expression, and contained ICAM-1 target sequences. The anti-atherogenic actions of MEG3 were inhibited by miR-147, and the anti-atherogenic actions of miR-147 suppression were also inhibited when ICAM-1 was overexpressed. Further, ICAM-1 overexpression showed activated roles in Wnt/ß-catenin and Jak/Stat signaling pathways. In low-density lipoprotein receptor (Ldlr)-/- mice, MEG3 overexpression reduced CD68+, CD3+ and ICAM-1 areas in lesions and increased collagen content. MEG3 inhibited HMEC-1 cell growth, migration and tube formation. The anti-atherogenic actions of MEG3 might be mediated via sponging miR-147, and thereby repressing the expression of ICAM-1.

Generation of hot electrons in nanostructures incorporating conventional and unconventional plasmonic materials.

The generation of energetic electrons is an effect occurring in any plasmonic nanostructure. However, the number of electrons with high energies generated optically in a plasmonic nanostructure can be relatively small. This is an intrinsic property of the collective plasmon excitations in a Fermi gas of electrons. But the choices of material and geometry have a great impact on the generation rate, and are therefore crucial for designing a nanostructure with a large rate of generation of energetic (hot) electrons. Here we test different plasmonic materials from the point of view of the generation of hot electrons (HEs). Our choice of materials includes both strongly-plasmonic materials (Au, Ag, Cu and Al) and crystals with strongly broadened plasmonic resonances (Pt, TiN and ZrN). Regarding the choice of geometry, we consider two types of nanostructures, single nanocrystals deposited over a dielectric substrate and metastructure absorbers, observing interesting opto-electronic properties. For single nanocrystals, the rate of HE generation is strongly material-dependent since the HE generation rate strongly depends on several physical parameters such as plasmonic enhancement, plasmonic resonance wavelength, Fermi energy, etc. Interestingly, the plasmonic meta-absorbers exhibit a different behaviour. The strongly-plasmonic metals, such as Au, Ag, Cu or Al, show very similar performances, while the materials with damped plasmon resonances demonstrate diverse and reduced rates of HE generation. The physical reason for these different behaviours lies in the dielectric functions of these materials. In the metastructures, plasmonic resonances are in the infrared region and the strongly-plasmonic materials behave as an almost ideal metal, whereas the second group of materials exhibits strong dissipation. This makes the responses from the metastructures made of crystals with damped plasmons strongly dependent on the choice of material. The physical principles described in our study can be useful for designing metastructures and nanodevices based on HEs, which can be used in photo-chemistry and opto-electronics.

Mindfulness-based stress reduction in patients with differentiated thyroid cancer receiving radioactive iodine therapy: a randomized controlled trial.

OBJECTIVE: The aim of this study was to evaluate the efficacy of mindfulness-based stress reduction (MBSR) on health-related quality of life (QoL), depression, and anxiety in patients with differentiated thyroid cancer (DTC) receiving radioactive iodine therapy (RIT). PATIENTS AND METHODS: A randomized controlled trial of MBSR with 120 DTC patients was performed. They were randomly assigned into the MBSR intervention group and usual care (UC) group. An 8-week MBSR program was administered to the MBSR group starting 8 weeks before RIT. Health-related QoL, depression, and anxiety were measured immediately before the start of MBSR (T1), immediately after RIT hospitalization was concluded (1 week after concluding the last MBSR session, T2), and 3 months after RIT hospitalization (T3), using the QoL Questionnaire Core 30 Items (QLQ-C30), Self-rating Depression Scale (SDS), and Self-rating Anxiety Scale (SAS). RESULTS: Fifty-three patients in the UC group and 49 patients in the MBSR group completed the study and were analyzed. Both the UC and MBSR groups reported low QoL and high SDS and SAS scores immediately after RIT hospitalization. Patients randomly assigned to the MBSR group showed significantly greater improvements in emotional function (P=0.012, d=-0.03 for T2 and d=1.17 for T3), fatigue (P=0.037, d=1.00 for T2 and d=-0.69 for T3), global QoL (P=0.015, d=1.61 for T2 and d=1.56 for T3), depression (P=0.027, d=-1.19 for T2 and d=-0.83 for T3), and anxiety (P=0.043, d=-1.00 for T2 and d=-0.86 for T3). CONCLUSION: An 8-week MBSR program significantly improved a wide range of scales in health-related QoL and mitigated depression and anxiety among DTC patients receiving RIT.

Chiral Plasmonic Nanocrystals for Generation of Hot Electrons: Toward Polarization-Sensitive Photochemistry.

The use of biomaterials, with techniques such as DNA-directed assembly or biodirected synthesis, can surpass top-down fabrication techniques in creating plasmonic superstructures in terms of spatial resolution, range of functionality, and fabrication speed. In particular, by enabling a very precise placement of nanoparticles in a bioassembled complex or through the controlled biodirected shaping of single nanoparticles, plasmonic nanocrystals can show remarkably strong circular dichroism (CD) signals. We show that chiral bioplasmonic assemblies and single nanocrystals can enable polarization-sensitive photochemistry based on the generation of energetic (hot) electrons. It is now established that hot plasmonic electrons can induce surface photochemistry or even reshape plasmonic nanocrystals. We show that merging chiral plasmonic nanocrystal systems and the hot-election generation effect offers unique possibilities in photochemistry, such as polarization-sensitive photochemistry promoting nonchiral molecular reactions, chiral photoinduced growth of a colloid at the atomic level, and chiral photochemical destruction of chiral nanocrystals. In contrast, for chiral molecular systems, the equivalent of the described effects is challenging to observe because molecular species typically exhibit very small CD signals. Moreover, we compare our findings with traditional chiral photochemistry at the molecular level, identifying new, different regimes for chiral photochemistry with possibilities that are unique for plasmonic colloidal systems. In this study, we bring together the concept of hot-electron generation and the field of chiral colloidal plasmonics. Using chiral plasmonic nanorod complexes as a model system, we demonstrate remarkably strong CD in both optical extinction and generation rates of hot electrons. Studying the regime of steady-state excitation, we discuss the influence of geometrical and material parameters on the chiral effects involved in the generation of hot electrons. Optical chirality and the chiral hot-electron response in the nanorod dimers result from complex interparticle interactions, which can appear in the weak coupling regime or in the form of Rabi splitting. Regarding practical applications, our study suggests interesting opportunities in polarization-sensitive photochemistry, in chiral recognition or separation, and in promoting chiral crystal growth at the nanoscale.

Active targeting drug-gold nanorod hybrid nanoparticles for amplifying photoacoustic signal and enhancing anticancer efficacy.

The development of theranostic nanomaterials with limited side effects and increased therapeutic efficacy is a promising approach for cancer imaging and therapy. In the present study, the development of a multifunctional metal-organic hybrid nanoparticle (NP) with enhanced photoacoustic (PA) imaging performance able to be actively uptaken by cancer cells for synergistic chemo-photothermal cancer therapy was reported. The theranostic NP was composed through the coordination effect between an ultrasmall gold nanorod (AuNR), a thick coating layer of the organic near-infrared dye IR780, and the anticancer drug doxorubicin (DOX), named AuNR@IR780/DOX-RGD-PEG. In addition, the theranostic NP surface was conjugated with targeting ligand RGD and a protective PEG shell, where the PEG played a role in concealing or exposing the RGD for specific targeting of the NPs to the cancer cells. The theranostic NP demonstrated a greatly enhanced PA imaging signal compared to AuNR or IR780, due to the fact that the electromagnetic field of the AuNR increased the light absorption efficiency of the IR780 coating based on the theoretical simulation results. Furthermore, the "Trojan-horse" active targeting strategy not only increased the uptake of NPs by tumor cells, but also decreased the non-specific uptake by healthy cells, thus limiting the side effects. This study developed a smart theranostic NP for enhanced cancer PA imaging and specific cancer therapy.

DNA-Guided Plasmonic Helix with Switchable Chirality.

The ability to dynamically tune the self-assembled structures of nanoparticles is of significant interest in the fields of chemistry and material studies. However, it continues to be challenging to dynamically tune the chiral superstructures of nanoparticles and actively switch the chiral optical properties thereof. Here, we dynamically controlled a gold nanorod 3D chiral plasmonic superstructure (a stair helix with a pinwheel end view) templated by a DNA origami supramolecular polymer, using DNA-toehold-mediated conformational change in the DNA template. The gold nanorod chiral plasmonic helix was controllably reconfigured between a tightly folded state (with a small inter-rod angle) and an extended state (with a wide inter-rod angle) of the same handedness, or between two mirror-image-like structures of opposite handedness. As a result, the chiral plasmonic properties of the gold nanorod helix superstructures, in terms of the circular dichroism amplitude, peak response frequency, and signature of chirality, were actively switched upon the DNA-guided structural reconfiguration. We envision that the strategy demonstrated here will boost the advancement of reconfigurable chiral materials with increased complexity for active light control applications through rational molecular design and predictable self-assembly procedures.

Photosensitizer-Encapsulated Ferritins Mediate Photodynamic Therapy against Cancer-Associated Fibroblasts and Improve Tumor Accumulation of Nanoparticles.

Nanoparticles have been widely tested as drug delivery carriers or imaging agents, largely because of their ability to selectively accumulate in tumors through the enhanced permeability and retention (EPR) effect. However, studies show that many tumors afford a less efficient EPR effect and that many nanoparticles are trapped in the perivascular region after extravasation and barely migrate into tumor centers. This is to a large degree attributed to the dense tumor extracellular matrix (ECM), which functions as a physical barrier to prevent efficient nanoparticle extravasation and diffusion. In this study, we report a photodynamic therapy (PDT) approach to enhance tumor uptake of nanoparticles. Briefly, we encapsulate ZnF16Pc, a photosensitizer, into ferritin nanocages, and then conjugate to the surface of the ferritin a single chain viable fragment (scFv) sequence specific to fibroblast activation protein (FAP). FAP is a plasma surface protein widely upregulated in cancer-associated fibroblasts (CAFs), which is a major source of the ECM fiber components. We found that the scFv-conjugated and ZnF16Pc-loaded ferritin nanoparticles (scFv-Z@FRT) can mediate efficient and selective PDT, leading to eradication of CAFs in tumors. When tested in bilateral 4T1 tumor models, we found that the tumor accumulation of serum albumin (BSA), 10 nm quantum dots (QDs), and 50 nm QDs was increased by 2-, 3.5-, and 18-fold after scFv-Z@FRT mediated PDT. Our studies suggest a novel and safe method to enhance the delivery of nanoparticles to tumors.

Size-dependent longitudinal plasmon resonance wavelength and extraordinary scattering properties of Au nanobipyramids.

Au nanobipyramids (NBPs) with sharp tips and narrow plasmon linewidths are ideal candidates for plasmonic applications. In this paper, we investigated the influencing factors of longitudinal plasmon resonance wavelength (LPRW) and scattering properties of single Au NBP by simulation. Compared with the volume, we establish the aspect ratio (length/width) as the dominant factor that affects the LPRW of Au NBPs. Plasmonic nanoparticles have been widely used for light-trapping enhancement in photovoltaics. To give a profound understanding of the superior light harvesting properties of Au NBPs, the near-field localization effect and far-field scattering mechanism of Au NBPs were investigated. Under the light injection at LPRW, the tip area shows near-field enhancement and the maximum scattering intensity appears on the side area of the waist owing to the remarkable optical absorption near the tips. Additionally, we confirm the fraction of light scattered into the substrate and angular distribution of the light scattered by the Au NBPs. The fraction of light scattered into the substrate reaches up to 97% from 400-1100 nm and preserves a broadband spectrum. This suggests that the NBP has a predominant forward scattering and reduced backward scattering. The excellent plasmonic scattering properties of Au NBPs are promising in photovoltaic devices and photothermal therapy.

Theranostic Hyaluronic Acid-Iron Micellar Nanoparticles for Magnetic-Field-Enhanced in†vivo Cancer Chemotherapy.

The delivery of therapeutic cancer agents using nanomaterials has recently attracted much attention. Although encouraging progress with chemotherapeutics has been made, tumor treatment response remains unsatisfactory. To address this concern, we constructed a new micellar nanocomplex by covalently conjugating hyaluronic acid (HA) with an iron oxide nanoparticle (IONP). When an external magnetic field was applied to the tumor area, HA-IONP specifically accumulated in the tumor, due to the strong IONP magnetism. In addition, HA was shown to bind to cluster determinant 44 (CD44), which is overexpressed on tumor cells. With combined magnetic, CD44, and enhanced permeability retention (EPR) targeting, the efficient delivery of HA-IONP to the tumor is expected to enhance cancer treatment efficiency. After encapsulation of the chemotherapy drug homocamptothecin (HCPT), the theranostic potency of HA-IONP/HCPT (HIH) was investigated both in vitro and in vivo. The improved tumor homing behavior of HIH was observed by magnetic resonance imaging (MRI) when an external magnetic field was used. Moreover, HIH showed remarkable tumor ablation efficiency, with magnetic targeting after 3 mg kg-1 intravenous administration (equivalent dose of free HCPT), and the tumors almost disappeared after treatment. No obvious systemic toxicity was detected. This excellent biocompatibility and tumor targetability suggests that HIH is a promising theranostic nanocomplex with great translational potency. Application of the HA-IONP platform could also be extended to delivery of other hydrophobic chemotherapy drugs or phototherapy agents.

Ultrabroadband absorber based on single-sized embedded metal-dielectric-metal structures and application of radiative cooling.

The realization of ultrabroadband absorption is a fundamental part of a thermal emitter, especially in the application of radiative cooling. This study involved proposing and systematically analyzing a novel structure termed as an embedded metal-dielectric-metal (EMDM) structure. The results in the case of an individual resonator indicated that the EMDM resonator displayed a broader full width at half maximum (FWHM) that was 1.9 times that of the metal-dielectric-metal (MDM) resonator due to mode matching at the terminated end and enhanced scattering intensity. With respect to the case of periodic resonators, single-sized periodic EMDM resonators are employed to achieve a broader FWHM that is 3.8 times that of the MDM resonators. In addition, a strong coupling effect is confirmed between localized MDM and hybrid modes. An application of lossy-dielectric based periodic three-dimensional EMDM resonators indicated that an average absorptivity of 0.85 in the entire atmospheric window (8-13 µm). The results revealed the potential of EMDM structures for radiative cooling devices and other ultrabroadband absorbers.

Mechanism of neuronal activity and synaptic transmission in rostral ventrolateral medulla.

Rostral ventrolateral medulla (RVLM) plays an essential role in blood pressure homeostasis. This study was aimed to investigate the mechanism of neuronal activity and synaptic transmission in the RVLM. Medulla oblongata slices were carefully obtained from brainstem of rats. With continues perfusion of artificial cerebrospinal fluid (ACSF), the spontaneous firing of slices and amplitudes were assayed by conventional whole cell patch-clamp recording after addition of gamma-aminobutyric acid (GABA), α-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and N-methyl d-aspartate (NMDA). Furthermore, the effects of agonist or antagonist targeted Type-A GABA (GABAA) or glutamate receptors on spontaneous excitatory postsynaptic potential (sEPSP) and spontaneous inhibitory postsynaptic potential (sIPSP) of neurons in RVLM were determined. The spontaneous firing of neurons in RVLM were inhibited by GABA (P<0.001) while were promoted by NMDA or AMPA (P<0.01 or P<0.001). In terms of sEPSP and sIPSP, the numbers of firing neurons in RVLM were both improved by GABAA receptor antagonist (P<0.01 or P<0.001) while were both decreased by GABAA receptor agonist or glutamate receptor antagonist (P<0.05, P<0.01 or P<0.001). The corresponding effects of agonist and antagonist on amplitudes were the same as the effects on number of firing neurons in RVLM. The spontaneous firing, sEPSP and sIPSP of neurons in RVLM were all activated by GABAA receptor antagonist while were all suppressed by GABAA receptor agonist or glutamate receptor antagonist.

Studies on the purification of polysaccharides separated from Tremella fuciformis and their neuroprotective effect.

The present study aimed to investigate the protective effect of purified polysaccharides from Tremella fuciformis against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The aqueous extract of Tremella fuciformis was purified using a DEAE-52 cellulose anion exchange column and a Sepharose G-100 column, respectively. A fraction termed TL04 with a 2,033 kDa molecular weight was obtained. The backbone of TL04 is composed of (1→2)­ and (1→4)-linked-mannose and (1→3)-linked-glucans. Results revealed that TL04 treatment improved cell viability and suppressed reactive oxygen species accumulation, lactose dehydrogenase release and caspase-3 activity, and ameliorated mitochondrial abnormal alteration caused by glutamate. TL04 pretreatment enhanced the level of B­cell lymphoma 2 (Bcl­2), and suppressed Bax expression and cytochrome c (Cyto C) release in glutamate-treated cells. Exposure to glutamate strongly increased the activity of caspase­8, caspase­9 and caspase­3, which were significantly reversed by TL04 pretreatment. The presence of Ac-DEVD-CHO (a caspase-3 inhibitor) markedly enhanced the potency of TL04 in improving the viability of glutamate-exposed DPC12 cells. Collectively, the results demonstrated that the purified polysaccharides separated from Tremella fuciformis (TL04) possess a neuroprotective effect against glutamate-induced DPC12 cell damage predominantly through the caspase-dependent mitochondrial pathway. The present study provides an experimental foundation supporting purified TL04 as a potential therapeutic agent for neurodegenerative diseases.