Dynamic repulsive interaction enables an asymmetric electron-phonon coupling for improving Raman scattering.

Two-dimensional (2D) materials are an excellent platform for surface-enhanced Raman spectroscopy (SERS). For ReS2, the Raman enhancement effect can be highly improved through the dipole-dipole interactions and synergistic resonance effects in the phase-engineering ReS2 films. However, the performance of the substrate can be improved further through regulating the electronic interaction between the ReS2 and probe molecules. Herein, a dynamic coulomb repulsion strategy is proposed to trigger an electronic state redistribution by asymmetric electrostatic interactions. With the phase-engineering ReS2/graphene heterostructure as a prototype, under laser excitation, the generated hot electrons in graphene and ReS2 can repel each other due to Coulomb interaction, which breaks the symmetrical distribution of hot electrons in ReS2, and increases the electronic concentration at the interface between ReS2 and the probe molecule. With R6G as the probe molecule, the asymmetric electron distribution and synergistic resonance effects on their interface improve the limit of detection to 10-12 M with an EF of 2.15 × 108. Meanwhile, the heterostructure also shows good uniformity, stability as well as unique anisotropy. This strategy can be generalized to other 2D heterostructures to obtain the ultrasensitive SERS substrates.

Ceftriaxone Modulates Ubiquitination of α-Amino-3-Hydroxy-5-Methyl-4-Isoxazole Propionic Acid Receptors to Improve Long-Term Potentiation Impairment Induced by Exogenous ß-Amyloid in a Glutamate Transporter-1 Dependent Manner.

Α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) are crucial for properties of synaptic plasticity, such as long-term potentiation (LTP). LTP impairment can occur early in the onset of Alzheimer's disease (AD). The downregulation or decreased abundance of AMPAR expression in the postsynaptic membrane is closely associated with LTP impairment. Ceftriaxone (Cef) can improve LTP impairment in the early stages of AD in a mouse model. The purpose of this study was to explore the mechanism underlying this process from the aspects of AMPAR expression and ubiquitination degree. In this study, we found that ß-amyloid (Aß) treatment induced hippocampal LTP impairment and AMPAR downregulation and ubiquitination. Cef pretreatment ameliorated Aß-induced hippocampal LTP impairment, reduced AMPAR ubiquitination, and increased AMPAR expression, especially in the plasma membrane, in Aß-treated mice. Administration of USP46 siRNA and DHK (a specific blocker of glutamate transporter-1) significantly inhibited the above effects of Cef, suggesting a role for anti-AMPAR ubiquitination and upregulation of glutamate transporter-1 (GLT-1) in the Cef-induced improvements mentioned above. The above findings demonstrate that pretreatment with Cef effectively mitigated Aß-induced impairment of hippocampal LTP by suppressing the ubiquitination process of AMPARs in a GLT-1-dependent manner. These results provide novel insights into the underlying mechanisms elucidating the anti-AD by Cef.

Multistage orbital hybridization induced by multisite exchange interactions in high-entropy perovskites for high oxygen evolution reaction.

The oxygen evolution reaction (OER) has garnered considerable attention because of its promising prospects in electrochemical energy conversion applications, but a significant challenge is faced by the insufficient understanding of sluggish OER kinetics. In fact, the intrinsic "acceptance-donation" process of electrons between active sites and reactants is responsible for improving OER activity. Herein, we suggest a multielement hybridization strategy to rematch spin electron occupation and energy splitting in high-entropy perovskites with multiple orbital coordination. In this concept, electronic hopping between t2g and eg orbitals among particular catalytic sites can be obviously enforced due to introducing more favorable energy levels from neighboring metal sites, which can demonstrate multistage orbital hybridization reaction activity. As a result, our proposed multistage-hybridized high-entropy perovskites display an impressive activity of 199.8 mA cm-2 as an overpotential of âˆ¼0.46 V, which is âˆ¼5.3 times that of pristine perovskite. Different from traditional catalyst designs, this study focuses on multistage orbital hybridization and electron exchange interactions through a multisite coordination mechanism to construct a fast reaction pathway. Our findings provide a new strategy for accelerating OER catalytic kinetics.

Ceftriaxone improves impairments in synaptic plasticity and cognitive behavior in APP/PS1 mouse model of Alzheimer's disease by inhibiting extrasynaptic NMDAR-STEP61 signaling.

Abnormal activation of the extrasynaptic N-methyl-d-aspartate receptor (NMDAR) contributes to the pathogenesis of Alzheimer's disease (AD). Ceftriaxone (Cef) can improve cognitive impairment by upregulating glutamate transporter-1 and promoting the glutamate-glutamine cycle in an AD mouse model. This study aimed to investigate the effects of Cef on synaptic plasticity and cognitive-behavioral impairment and to unravel the associated underlying mechanisms. We used an APPswe/PS1dE9 (APP/PS1) mouse model of AD in this study. Extrasynaptic components from hippocampal tissue homogenates were isolated using density gradient centrifugation. Western blot was performed to evaluate the expressions of extrasynaptic NMDAR and its downstream elements. Intracerebroventricular injections of adeno-associated virus (AAV)-striatal enriched tyrosine phosphatase 61 (STEP61 ) and AAV-STEP61 -shRNA were used to modulate the expressions of STEP61 and extrasynaptic NMDAR. Long-term potentiation (LTP) and Morris water maze (MWM) tests were performed to evaluate the synaptic plasticity and cognitive function. The results showed that the expressions of GluN2B and GluN2BTyr1472 in the extrasynaptic fraction were upregulated in AD mice. Cef treatment effectively prevented the upregulation of GluN2B and GluN2BTyr1472 expressions. It also prevented changes in the downstream signals of extrasynaptic NMDAR, including increased expressions of m-calpain and phosphorylated p38 MAPK in AD mice. Furthermore, STEP61 upregulation enhanced, whereas STEP61 downregulation reduced the Cef-induced inhibition of the expressions of GluN2B, GluN2BTyr1472 , and p38 MAPK in the AD mice. Similarly, STEP61 modulation affected Cef-induced improvements in induction of LTP and performance in MWM tests. In conclusion, Cef improved synaptic plasticity and cognitive behavioral impairment in APP/PS1 AD mice by inhibiting the overactivation of extrasynaptic NMDAR and STEP61 cleavage due to extrasynaptic NMDAR activation.

Ceftriaxone ameliorates hippocampal synapse loss by inhibiting microglial/macrophages activation in glial glutamate transporter-1 dependent manner in the APP/PS1 mouse model of Alzheimer's disease.

Synapse loss is a major contributor to cognitive dysfunction in Alzheimer's disease (AD). Impairments in the expression and/or glutamate uptake activity of glia glutamate transporter-1 (GLT-1) contribute to synapse loss in AD. Hence, targeting the restoration of GLT-1 activity may have potential for alleviating synapse loss in AD. Ceftriaxone (Cef) can upregulate the expression and glutamate uptake activity of GLT-1 in many disease models, including those for AD. The present study investigated the effects of Cef on synapse loss and the role of GLT-1 using APP/PS1 transgenic and GLT-1 knockdown APP/PS1 AD mice. Furthermore, the involvement of microglia in the process was investigated due to its important role in synapse loss in AD. We found that Cef treatment significantly ameliorated synapse loss and dendritic degeneration in APP/PS1 AD mice, evidenced by an increased dendritic spine density, decreased dendritic beading density, and upregulated levels of postsynaptic density protein 95 (PSD95) and synaptophysin. The effects of Cef were suppressed by GLT-1 knockdown in GLT-1+/-/APP/PS1 AD mice. Simultaneously, Cef treatment inhibited ionized calcium binding adapter molecule 1 (Iba1) expression, decreased the proportion of CD11b+CD45hi cells, declined interleukin-6 (IL-6) content, and reduced the co-expression of Iba1 with PSD95 or synaptophysin in APP/PS1 AD mice. In conclusion, Cef treatment ameliorated synapse loss and dendritic degeneration in APP/PS1 AD mice in a GLT-1-dependent manner, and the inhibitory effect of Cef on the activation of microglia/macrophages and their phagocytosis for synaptic elements contributed to the mechanism.

Dynamic orbital hybridization triggered spin-disorder renormalization via super-exchange interaction for oxygen evolution reaction.

The oxygen evolution reaction (OER) underpins many aspects of energy storage and conversion in modern industry and technology, but which still be suffering from the dilemma of sluggish reaction kinetics and poor electrochemical performance. Different from the viewpoint of nanostructuring, this work focuses on an intriguing dynamic orbital hybridization approach to renormalize the disordering spin configuration in porous noble-metal-free metal-organic frameworks (MOFs) to accelerate the spin-dependent reaction kinetics in OER. Herein, we propose an extraordinary super-exchange interaction to reconfigure the domain direction of spin nets at porous MOFs through temporarily bonding with dynamic magnetic ions in electrolytes under alternating electromagnetic field stimulation, in which the spin renormalization from disordering low-spin state to high-spin state facilitates rapid water dissociation and optimal carrier migration, leading to a spin-dependent reaction pathway. Therefore, the spin-renormalized MOFs demonstrate a mass activity of 2,095.1 A gmetal-1 at an overpotential of 0.33 V, which is about 5.9 time of pristine ones. Our findings provide a insight into reconfiguring spin-related catalysts with ordering domain directions to accelerate the oxygen reaction kinetics.

Light-driven Orderly Assembly of Ir-atomic Chains to Integrate a Dynamic Reaction Pathway for Acidic Oxygen Evolution.

This work suggests an intriguing light-driven atomic assembly proposal to orderly configure the distribution of reactive sites to optimize the spin-entropy-related orbital interaction and charge transfer from electrocatalysts to intermediates. Herein, the introduced fluorine (F) atoms acting as photo-corrosion centres in MnO1.9 F0.1 effectively soften the bonding interaction of Mn-O bonds in the IrCl3 solution. Therefore, partial Mn atoms can be successively replaced to form orderly atomic-hybridized catalysts with a spin-related low entropy due to the coexistence of Ir-atomic chains and clusters. The time-related elemental analysis demonstrates that the dynamic dissolution/redeposition of Ir clusters in acidic oxygen evolution leads to a reintegration of the reaction pathway to seek the switchable rate-limiting step with a lower activation energy.

Significantly increased Raman enhancement enabled by hot-electron-injection-induced synergistic resonances on anisotropic ReS2 films.

Two-dimensional (2D) materials are an excellent platform for surface-enhanced Raman spectroscopy (SERS). However, a poor detection sensitivity hinders their practical application. Exciton resonance (µex) can improve SERS significantly by lending intensity to nearby charge-transfer resonance. Coincidentally, for ReS2, the enhanced µex can be achieved through the injection of excited-state electrons which can adjust the energy band to the SERS detection range. Moreover, ReS2 has strong anisotropic properties, which adds an additional dimension for SERS. Therefore, ReS2 is an ideal candidate to realize highly sensitive anisotropic SERS. In this paper, the metallic T phase of ReS2 is introduced to the semiconducting Td phase by phase engineering. The photoinduced electron tunneling from the T phase to the Td phase can tune exciton emissions to the visible region, which effectively facilitates the photoinduced charge transfer processes. With RhB as the probe molecule, the synergistic resonance effects improve the limit of detection to 10-9 M with the enhancement factor up to about 108. Meanwhile, the obtained ultrasensitive SERS substrates also show good uniformity, stability as well as unique anisotropy. Our results open a new perspective in the improvement of the SERS performance.

Emergent helical edge states in a hybridized three-dimensional topological insulator.

As the thickness of a three-dimensional (3D) topological insulator (TI) becomes comparable to the penetration depth of surface states, quantum tunneling between surfaces turns their gapless Dirac electronic structure into a gapped spectrum. Whether the surface hybridization gap can host topological edge states is still an open question. Herein, we provide transport evidence of 2D topological states in the quantum tunneling regime of a bulk insulating 3D TI BiSbTeSe2. Different from its trivial insulating phase, this 2D topological state exhibits a finite longitudinal conductance at ~2e2/h when the Fermi level is aligned within the surface gap, indicating an emergent quantum spin Hall (QSH) state. The transition from the QSH to quantum Hall (QH) state in a transverse magnetic field further supports the existence of this distinguished 2D topological phase. In addition, we demonstrate a second route to realize the 2D topological state via surface gap-closing and topological phase transition mechanism mediated by a transverse electric field. The experimental realization of the 2D topological phase in a 3D TI enriches its phase diagram and marks an important step toward functionalized topological quantum devices.

Asymmetric Exchange Interaction Induces Highly Efficient Alkaline Hydrogen Evolution in RhFe Bimetallene.

An RhFe bimetallene with Fe atoms doped into Rh host for efficient hydrogen evolution reaction (HER), is constructed. When two doped Fe atoms occupy neighboring asymmetric spatial positions, their asymmetric exchange interaction drives electron hopping between the dxy orbital of a Fe atom and the dz 2 orbital of its neighboring Fe atom to push the d band center closer to the Fermi level as a result of electronic state reconstruction. The designed bimetallene with thickness of 0.77 nm (5 atomic layers), possesses excellent HER performance. The low overpotentials of 24.4 and 34.6 mV are achieved at the 10 and 100 mA cm-2 current densities in 1 m KOH solution, respectively. An ultra-low Tafel slope of 8.9 mV dec-1 shows that this kind of RhFe bimetallene is of an ultrafast kinetic process. This work provides a strategy for designing HER catalysts with double metal composites.

Integrated Spatial Modulation and STBC-VBLAST Design toward Efficient MIMO Transmission.

In this contribution, the concept of spatial modulation (SM) is firstly integrated into the structure of space-time block codes (STBC)-aided vertical Bell-labs layered space-time (VBLAST) systems, in order to strike a balanced tradeoff among bit error ratio (BER), spectral efficiency and computational complexity. First of all, in order to enhance the BER performance of STBC-VBLAST, we advocate an effective transmit power allocation (TPA) scheme with negligible implementation costs, while dividing the STBC and VBLAST layers with alleviated interference, so as to facilitate combination with SM. Then, we further utilize the unique structure of SM for enhancing the spectral efficiency of original STBC-VBLAST, wherein the information is conveyed by not only the amplitude/phase modulation (APM) symbols but also the antenna indices. In addition, constellation sets of STBC symbols are specifically designed to be rotated to make full use of the degrees of freedom. Finally, the performance advantages of the above-mentioned structures over traditional STBC-VBLAST are demonstrated by the theoretical derivation of a closed-form expression for the union bound on the bit error probability for various spectral efficiencies, and they are supported by simulation results.

Spin-related symmetry breaking induced by half-disordered hybridization in BixEr2-xRu2O7 pyrochlores for acidic oxygen evolution.

While acidic oxygen evolution reaction plays a critical role in electrochemical energy conversion devices, the sluggish reaction kinetics and poor stability in acidic electrolyte challenges materials development. Unlike traditional nano-structuring approaches, this work focuses on the structural symmetry breaking to rearrange spin electron occupation and optimize spin-dependent orbital interaction to alter charge transfer between catalysts and reactants. Herein, we propose an atomic half-disordering strategy in multistage-hybridized BixEr2-xRu2O7 pyrochlores to reconfigure orbital degeneracy and spin-related electron occupation. This strategy involves controlling the bonding interaction of Bi-6s lone pair electrons, in which partial atom rearrangement makes the active sites transform into asymmetric high-spin states from symmetric low-spin states. As a result, the half-disordered BixEr2-xRu2O7 pyrochlores demonstrate an overpotential of ~0.18 V at 10 mA cm-2 accompanied with excellent stability of 100 h in acidic electrolyte. Our findings not only provide a strategy for designing atom-disorder-related catalysts, but also provides a deeper understanding of the spin-related acidic oxygen evolution reaction kinetics.

Polarization-induced efficient charge separation in an electromagnetic coupling MOF for enhancing CO2 photocatalytic reduction.

Rapid recombination of photogenerated carriers severely impairs the performance of photocatalysts, while polarization is an effective driving force for increasing the charge separation and hence improving the photocatalytic activity. In this work, a series of magnetoelectric-coupled layered metal-organic framework (MOF) catalysts with different Co-doped contents (denoted as Ni-MOF and CoxNi1-x-MOF) are fabricated with different polarities and employed as novel photocatalysts for CO2 photocatalytic reduction reaction. Our experiments show that the highest charge separation efficiency occurs in the Co0.1Ni0.9-MOF sample which has a maximal polarization. This Co0.1Ni0.9-MOF material has a best CO2 reduction performance of 38.74 µmol g-1h-1 which is at a high level in the currently reported layered materials. Meanwhile, it is found that a series of CoxNi1-x-MOF samples all display selectivity close to 100% for CO2 reduction to CO, which is desirable for industrial applications. Theoretical analysis shows that Co doping alters the degree of distortion of the asymmetrical Ni-centered octahedron {NiN2O4} in Ni-MOF by replacing Ni due to the magnetoelectric coupling effect and Jahn-Teller effect, which results in adjustable polarity of CoxNi1-x-MOF. This work provides new insights on how to improve photogenerated charge separation in MOF by enhancing polarization.

The exchange between anions and cations induced by coupled plasma and thermal annealing treatment for room-temperature ferromagnetism.

Two-dimensional (2D) materials, with outstanding magnetic properties at room temperature, are highly desirable for the future spintronic and nanoscale electronic industry. However, most of the 2D systems are not of magnetic nature due to thermal fluctuations. Herein, we propose a novel strategy to induce robust room-temperature ferromagnetism in the originally nonmagnetic 2D ReS2 by the exchange between anions and cations. The vacancies are created by argon plasma treatment, which lowers the formation energy of point defects. The subsequent annealing facilitates the movement of the cations into the anion sites, giving rise to antisite defects, which leads to a significant increase in the magnetization. First-principles calculations demonstrate that the point defect with respect to the antisite substitution from Re to S is responsible for the extraordinary room-temperature ferromagnetism. This work opens a new door to the design of spin electronic structures by controllable antisite defects.

Strong histamine torsion Raman spectrum enables direct, rapid, and ultrasensitive detection of allergic diseases.

Allergic diseases are closely related to degranulation and release of histamine and difficult to diagnose because non-allergic diseases also exhibit the same clinical symptoms as allergy. Here, we report direct, rapid, and ultrasensitive detection of histamine using low-frequency molecular torsion Raman spectroscopy. We show that the low-frequency (<200 cm-1) Raman spectral intensities are stronger by one order of magnitude than those of the high-frequency Raman ones. Density functional theory calculation and nuclear magnetic resonance spectroscopy identify the strong spectral feature to be from torsions of carbon-carbon single bonds, which produce large variations of the polarizability densities in the imidazole ring and ethyl amino side chain. Using an omniphobic substrate and surface plasmonic effect of Au@SiO2 nanoparticles, the detection limit (signal-noise ratio >3) of histamine reaches 10-8 g/L in water and 10-6 g/L in serum. This scheme thus opens new lines of inquiry regarding the clinical diagnosis of allergic diseases.

Sulbactam improves binding property and uptake capacity of glutamate transporter-1 and decreases glutamate concentration in the CA1 region of hippocampus of global brain ischemic rats.

Glutamate transporter-1 (GLT-1) removes most glutamate in the synaptic cleft. Sulbactam confers neuronal protection against ischemic insults in the hippocampal CA1 region accompanied by the upregulation of GLT-1 expression in rats. The present study further investigates the effect of sulbactam on the binding property and uptake capacity of GLT-1 for glutamate, and the change in extracellular glutamate concentration in the hippocampal CA1 region of rats with global brain ischemia. The binding property and uptake capacity of GLT-1 were measured using a radioligand binding and uptake assay, respectively, with L-3H-glutamate. The extracellular glutamate concentration was detected using microdialysis and high-performance liquid chromatography-mass spectrometry. Neuropathological evaluation was performed based on thionin staining. It was shown that sulbactam pre-treatment changed GLT-1 binding property, including increased Bmax and decreased Kd values, increased GLT-1 uptake capacity for glutamate, and inhibited the elevation of extracellular glutamate concentration in rats with global cerebral ischemia. These effects of sulbactam were accompanied by its neuronal protection on the hippocampal CA1 neurons against delayed neuronal death resulted from ischemic insult. Furthermore, administration of GLT-1 antisense oligodeoxynucleotides, which inhibited the expression of GLT-1, blocked the aforementioned sulbactam-related effects, which suggested that GLT-1 upregulation mediated the above effect although other mechanisms independent of the upregulation of GLT-1 expression could not be excluded. It could be concluded that sulbactam improves the binding property and uptake capacity of GLT-1 for glutamate and then reduces the glutamate concentration and excitotoxicity during global cerebral ischemia, which contributes to the neuroprotection of sulbactam against brain ischemia.

Spin-sate reconfiguration induced by alternating magnetic field for efficient oxygen evolution reaction.

Oxygen evolution reaction (OER) plays a determining role in electrochemical energy conversion devices, but challenges remain due to the lack of effective low-cost electrocatalysts and insufficient understanding about sluggish reaction kinetics. Distinguish from complex nano-structuring, this work focuses on the spin-related charge transfer and orbital interaction between catalysts and intermediates to accelerate catalytic reaction kinetics. Herein, we propose a simple magnetic-stimulation approach to rearrange spin electron occupation in noble-metal-free metal-organic frameworks (MOFs) with a feature of thermal-differentiated superlattice, in which the localized magnetic heating in periodic spatial distribution makes the spin flip occur at particular active sites, demonstrating a spin-dependent reaction pathway. As a result, the spin-rearranged Co0.8Mn0.2 MOF displays mass activities of 3514.7 A gmetal-1 with an overpotential of ~0.27 V, which is 21.1 times that of pristine MOF. Our findings provide a new paradigm for designing spin electrocatalysis and steering reaction kinetics.

Preoperative Serum Gamma-Glutamyltransferase as a Prognostic Biomarker in Patients Undergoing Radical Cystectomy for Bladder Cancer.

BACKGROUND: Serum gamma-glutamyltransferase (GGT) has been reported to be correlated with survival in a variety of malignancies. However, its effect on patients with bladder cancer (BC) treated by radical cystectomy has never been evaluated. PATIENTS AND METHODS: We retrospectively evaluated 263 patients who underwent radical surgery in our center. Baseline features, hematologic variables, and follow-up data were obtained. The endpoints included overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). The relationship between GGT and survival were evaluated. RESULTS: The median follow-up period for all patients was 34.7 (22.9-45.9) months. At the last follow-up, 67 patients died, 51 patients died of cancer, 92 patients experienced disease recurrence. Patients with an elevated serum GGT had a higher rate of pT3-T4 tumors. Patients with a higher preoperative serum GGT had a lower rate of OS, CSS and DFS (P < 0.001 for all). Multivariate analysis identified that preoperative serum GGT was independent predictor of OS (HR: 3.027, 95% CI: 1.716-5.338; P < 0.001), CSS (HR: 2.115, 95% CI: 1.093-4.090; P = 0.026), DFS (HR: 2.584, 95% CI: 1.569-4.255; P < 0.001). Age, diabetes history, pathologic T stage, and lymph node status also were independent predictors of prognosis for BC patients. CONCLUSIONS: Our results indicated that preoperative serum GGT was an independent prognosis predictor for survival of BC patients after radical cystectomy, and can be included in the prognostic models.

Recharged Catalyst with Memristive Nitrogen Reduction Activity through Learning Networks of Spiking Neurons.

Electrocatalysis from N2 to NH3 has been increasingly studied because it provides an environmentally friendly avenue to take the place of the current Haber-Bosch method. Unfortunately, the conversion of N2 to NH3 is far below the necessary level for implementation at a large scale. Inspired by signal memory in a spiking neural network, we developed rechargeable catalyst technology to activate and remember the optimal catalytic activity using manageable electrical stimulation. Herein, we designed double-faced FeReS3 Janus layers that mimic a multiple-neuron network consisting of resistive switching synapses, enabling a series of intriguing multiphase transitions to activate undiscovered catalytic activity; the activation energy barrier is clearly reduced via an active site conversion between two nonequivalent surfaces. Electrical field-stimulated FeReS3 demonstrates a Faradaic efficiency of 43% and the highest rate of 203 µg h-1 mg-1 toward NH3 synthesis. Moreover, this rechargeable catalyst displays unprecedented catalytic performance that persists for up to 216 h and can be repeatedly activated through a simple charging operation.