While surface strain engineering in shaped and bimetallic nanostructures offers additional variables for manoeuvring the catalysis, manipulating isotropic strain distributions in nanostructures remains a great challenge to reach higher tiers of the catalyst’s design. Herein, we report an efficient approach to construct a unique class of core/shell palladium–lead (Pd–Pb)/Pd nanosheets (NSs) and nanocubes (NCs) with homogeneous tensile strain along [001] on both the top-Pd and edge-Pd surfaces for boosting oxygen reduction reaction (ORR). These core/shell Pd–Pb/Pd NSs and Pd–Pb/Pd NCs exhibit over 160% and 140% increases in mass activity and over 114% and 98% increases in specific activity when compared with these unshelled counterparts, respectively. Especially, the Pd3Pb/Pd NSs show the ORR mass and specific activities of 0.57 A/mgPd and 1.31 mA/cm2 at 0.90 V versus reversible hydrogen electrode, which are 8.8 (6.5) and 9.4 (9.8) times higher than those of the commercial Pd/C (Pt/C), respectively. The valence band photoemission spectra and first-principles calculations collectively show that the tensile strained Pd shell results in an upshift of the d-band-center of Pd, weakening the chemisorption of oxygenated species due to the contribution of the antibonding orbital. In addition, the Pd3Pb/Pd NSs and NCs with intermetallic core and homogeneous few layers of Pd shell can sustain at least 20 000 potential cycles with negligible activity decay and composition changes. The present work provides a new direction for the design of highly active and stable catalysts for fuel cells and beyond.
Despite the fact that many strategies have been developed to improve the efficiency of the oxygen evolution reaction (OER), the precise modulation of the surface electronic properties of catalysts to improve their catalytic activity is still challenging. Herein, we demonstrate that the surface active electron density of Co3O4 can be effectively regulated by an argon‐ion irradiation method. X‐ray photoelectron and synchrotron x‐ray absorption spectroscopy, UV photoelectron spectrometry, and DFT calculations show that the surface active electron density band center of Co3O4 has been upshifted, leading to a significantly enhanced absorption capability of the oxo group. The optimized Co3O4‐based catalysts exhibit an excellent overpotential of 260 mV at 10 mA cm−2 and Tafel slope of 54 mV dec−1, superior to the capability of the benchmark RuO2, representing one of the best Co‐based OER catalysts. This approach could guide the future rational design and discovery of ideal electrocatalysts.
Background and aims: Diabetic kidney is more sensitive to ischemia/reperfusion (I/R) injury, which is associated with increased oxidative stress and impaired nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling. Melatonin, a hormone that is secreted with the rhythm of the light/dark cycle, has antioxidative effects in reducing acute kidney injury (AKI). However, the molecular mechanism of melatonin protection against kidney I/R injury in the state of diabetes is still unknown. In the present study, we hypothesized that melatonin attenuates renal I/R injury in diabetes by activating silent information regulator 2 associated protein 1 (SIRT1) expression and Nrf2/HO-1 signaling. Methods: Control or streptozotocin (STZ)-induced Type 1 diabetic rats were treated with or without melatonin for 4 weeks. Renal I/R injury was achieved by clamping both left and right renal pedicles for 30 min followed by reperfusion for 48 h. Results: Diabetic rats that were treated with melatonin undergoing I/R injury prevented renal injury from I/R, in aspects of the histopathological score, cell apoptosis, and oxidative stress in kidney, accompanied with decreased expressions of SIRT1, Nrf2, and HO-1 as compared with those in control rats. All these alterations were attenuated or prevented by melatonin treatment; but these beneficial effects of melatonin were abolished by selective inhibition of SIRT1 with EX527. Conclusion: These findings suggest melatonin could attenuate renal I/R injury in diabetes, possibly through improving SIRT1/Nrf2/HO-1 signaling.
Even though extensive efforts have been devoted to pursue promising electrocatalysts, the design of high-efficiency and low-cost electrocatalysts continues to be a formidable challenge for commercializing electrochemical energy technologies. Herein, we report the successful creation of a class of three-dimensional ordered Pd3Pb nanosheet assemblies (NSAs) via a wet-chemical approach. Such controlled nanostructures with ordered phase and highly open structure exhibit enhanced electrochemical activity and durability for both the anodic methanol oxidation reaction (MOR) and cathodic oxygen reduction reaction (ORR). In particular, the ordered Pd3Pb NSAs show ORR mass and specific activities of 0.697 A mgPd –1 and 0.989 mA cm–2 at 0.90 V versusthe reversible hydrogen electrode (RHE), which are 8.3 (10.9) and 7.5 (6.4) times higher than those of the commercial Pt/C (Pd/C), respectively, making them among the most efficient catalysts ever achieved for Pd-based ORR catalysts to date. In addition, the ordered Pd3Pb NSAs can even sustain at least 20000 potential cycles with limited activity decay and structure change.
Enhanced levels of expression of urokinase receptor (uPAR) and certain integrins have been linked to cancer cell progression. This has classically been attributed to matrix degradation via the activation of the urokinase (uPA)/plasmin system and modulation of cell motility and survival through integrin engagement. More recently, uPAR has been shown to play multiple roles independent of protease activity. Specifically, uPAR has been shown to be intimately involved in the regulation of cell adhesion, migration and proliferation in part through interactions with other membrane partners, including integrins. The goal of this review is to summarize recent insights in the function of uPAR/integrin interactions, to provide a framework for understanding the importance of these interactions in the context of cancer, and to highlight its potential as a target for therapeutic intervention.
Many nociceptive, inflammatory, and neuropathic pathways contribute to perioperative pain. Although opioids have long been a mainstay for perioperative analgesia, other non-opioid therapies, and dexmedetomidine, in particular, have been increasingly used as part of a multimodal analgesic regimen to provide improved pain control while minimizing opioid-related side effects. This article reviews the evidence supporting the preoperative, intraoperative, and postoperative efficacy of dexmedetomidine as an adjuvant, and the efficacy of intravenous, spinal canal, and nerve block analgesia with dexmedetomidine for perioperative acute pain treatment. While there have not been any large-scale clinical trials conducted, the current body of evidence suggests that dexmedetomidine is suitable for use as an adjuvant analgesic at all perioperative stages. However, there are potential adverse effects, such as hypotension and bradycardia, which must be taken into consideration by clinicians.
Background. A strong ongoing intraoperative stress response can cause serious adverse reactions and affect the postoperative outcome. This study evaluated the effect of intranasally administered dexmedetomidine (DEX) in combination with local anesthesia (LA) on the relief of stress and the inflammatory response during functional endoscopic sinus surgery (FESS). Methods. Sixty patients undergoing FESS were randomly allocated to receive either intranasal DEX (DEX group) or intranasal saline (Placebo group) 1 h before surgery. Stress hormones, inflammatory markers, postoperative pain relief, hemodynamic variables, blood loss, surgical field quality, body movements, and satisfaction were assessed. Results. Plasma epinephrine, norepinephrine, and blood glucose levels were significantly lower in DEX group as were the plasma IL-6 and TNF-α levels (P < 0.05). The weighted areas under the curve (AUCw) of the VAS scores were also significantly lower in DEX group at 2–12 h after surgery (P < 0.001). Furthermore, hemodynamic variables, blood loss, body movements, discomfort with hemostatic stuffing, surgical field quality, and satisfaction scores of patients and surgeons were significantly better (P < 0.05) in DEX group. Conclusions. Patients receiving intranasal DEX with LA for FESS exhibited less perioperative stress and inflammatory response as well as better postoperative comfort with hemostatic stuffing and analgesia.
Unraveling the essence of hydrogen adsorption and desorption behaviors can fundamentally guide catalyst design and promote catalytic performance. Herein, the regulation of hydrogen adsorption is systematically investigated by d–d orbital interaction of metallic tungsten dioxide (WO2). Theoretical simulations show that the incorporation of post‐transition metal atoms including Fe, Co, Ni, and Cu can gradually reduce the bond order of W—M sites, consequently weakening the hydrogen adsorption and accelerating the hydrogen evolution reaction (HER) process. Under that theoretical guidance, various 3d metal doped WO2 electrocatalysts are systematically screened for HER catalysis. Among them, the Ni‐WO2/nickel foam exhibits an overpotential of 41 mV (−10 mA cm−2) and Tafel slope down to 47 mV dec−1 representing the best tungsten‐based HER catalysts so far. This work demonstrates that optimizing hydrogen adsorption via d–d orbital modulation is an effective approach to developing efficient and robust catalysts.
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