Remote ischemic conditioning attenuates oxidative stress and inflammation via the Nrf2/HO-1 pathway in MCAO mice.

The protective effects of remote ischemic conditioning (RIC) on acute ischemic stroke have been reported. However, the protective mechanisms of RIC have not been fully elucidated. This study aimed to investigate whether RIC could reduce oxidative stress and inflammatory responses in middle cerebral artery occlusion (MCAO)-reperfusion mice via the nuclear factor-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. C57BL/6 mice were subjected to MCAO and underwent RIC twice daily at 1, 3, and 7 days after MCAO. ML385 was used to specifically inhibit Nrf2 in MCAO mice. Neurological deficit scores, infarct volume, and hematoxylin-eosin (HE) staining were assessed. Oxidative stress levels were assessed based on total antioxidant capacity (TAC), malonaldehyde (MDA), superoxide dismutase (SOD), and glutathione/glutathione disulfide (GSH/GSSG). mRNA levels were detected using real-time polymerase chain reaction (PCR), and protein levels were detected using western blotting and enzyme-linked immunosorbent assay (ELISA). Protein localization was investigated using immunofluorescence staining. RIC significantly reduced infarct volume and improved neurological function and histological changes after MCAO. RIC significantly increased TAC, SOD, and GSH/GSSG levels and decreased MDA levels. RIC significantly increased Nrf2 and HO-1 mRNA levels and decreased Keap1, NLRP3, and Cleaved Caspase-1 mRNA levels. RIC significantly increased Nrf2, HO-1, and NQO1 protein expression and decreased Keap1, NLRP3, Cleaved Caspase-1, Cleaved IL-1ß, IL-6, and TNF-α protein expression. RIC promoted the activation and translocation of Nrf2 into the nucleus. The protective effects of RIC were abolished by ML385 treatment. In conclusion, our findings suggest that RIC alleviates oxidative stress and inflammatory responses via the Nrf2/HO-1 pathway, which in turn improves neurobehavioral function. RIC may provide novel therapeutic options for acute ischemic stroke.

Role of lipocalin 2 in stroke.

Stroke is the second leading cause of death worldwide; however, the treatment choices available to neurologists are limited in clinical practice. Lipocalin 2 (LCN2) is a secreted protein, belonging to the lipocalin superfamily, with multiple biological functions in mediating innate immune response, inflammatory response, iron-homeostasis, cell migration and differentiation, energy metabolism, and other processes in the body. LCN2 is expressed at low levels in the brain under normal physiological conditions, but its expression is significantly up-regulated in multiple acute stimulations and chronic pathologies. An up-regulation of LCN2 has been found in the blood/cerebrospinal fluid of patients with ischemic/hemorrhagic stroke, and could serve as a potential biomarker for the prediction of the severity of acute stroke. LCN2 activates reactive astrocytes and microglia, promotes neutrophil infiltration, amplifies post-stroke inflammation, promotes blood-brain barrier disruption, white matter injury, and neuronal death. Moreover, LCN2 is involved in brain injury induced by thrombin and erythrocyte lysates, as well as microvascular thrombosis after hemorrhage. In this paper, we review the role of LCN2 in the pathological processes of ischemic stroke; intracerebral hemorrhage; subarachnoid hemorrhage; and stroke-related brain diseases, such as vascular dementia and post-stroke depression, and their underlying mechanisms. We hope that this review will help elucidate the value of LCN2 as a therapeutic target in stroke.

Design, Synthesis, and Photocatalytic Application of Moisture-Stable Hybrid Lead-Free Perovskite.

The employment of hybrid perovskite MAPbX3 (MA = CH3NH3+, X = Br or I) as photocatalysts in a photocatalytic hydrogen evolution reaction represents a promising approach to store solar energy. However, the toxicity of Pb makes these materials difficult to pass environmental evaluation while the intrinsic moisture sensitivity puts forward high anhydrous requirements in photocatalysts synthesis, storage, and application, which further reduces their service life. Herein, we demonstrate a hydrogen-bond-free strategy to synthesize moisture-stable hypotoxic hybrid perovskite for photocatalytic application by replacing traditional protonated countercations with alkylated countercations in a Pb-free hybrid system, which prevents water eroding hybrid perovskites via strong hydrogen bonds. A zero-dimensional Bi-based perovskite (3-ethylbenzo[d]thiazol-3-ium)4Bi2I10 (EtbtBi2I10) was synthesized, which contains dimeric (Bi2I10)4- formed by edge-sharing (BiI6) octahedra being different from the binuclear cluster in widely studied MA3Bi2I9. Theoretical calculations indicate that the electron communication between inorganic and organic moieties is responsible for its broadband absorption with a narrow band gap of 2.04 eV. EtbtBi2I10 exhibits excellent stability in distilled water, moisture air, acid solution, and UV-light irradiation. It shows effective photocatalytic performance in HI splitting to generate hydrogen with the performance comparable with MAPbI3. Introducing electron and hole-transporting channels drastically enhances the photocatalytic reaction.

Prevalence and risk factors of axial neck pain in patients undergoing multilevel anterior cervical decompression with fusion surgery.

OBJECTIVES: The aim of this study was to explore the prevalence and risk factors for axial neck pain in patients undergoing multilevel anterior cervical decompression with fusion surgery. METHODS: In this study, 88 patients, who underwent multilevel anterior cervical decompression with fusion surgery from January 2012 to January 2017, were retrospectively reviewed. Based on the postoperative axial neck pain, the patients were classified into two groups: axial pain group and no axial pain group. The patients were followed up 3 weeks, 3 months, and 1 year after cervical anterior surgery for the early- and long-term clinical evaluation. The possible effect factors included demographic variables (age, sex, BMI, smoking, drinking, heart disease, hypertension, diabetes, preoperative kyphosis, preoperative axial neck pain, preoperative JOA scores, and ODI) and surgery-related variables (surgical option, vertebral lesions, spinal canal stenosis rate, superior fusion segment, presence of intramedullary high signal intensity). RESULTS: The prevalence of axial neck pain was 27.3% (24 cases of 88). Our results showed that preoperative axial neck pain (62% vs 23%, P < 0.001) and preoperative kyphosis (42% vs 21.9%, P < 0.001) were risk factors for axial pain after multilevel anterior cervical surgery. Additionally, for patients with preoperative cervical kyphosis, compared to no axial pain group, the axial neck group was significantly more likely to exist a higher preoperative angle of C2-7 (13.31 ± 2.33 vs 7.33 ± 2.56, P < 0.001) and a higher correction range for kyphosis (20.24 ± 4.12 vs 12.34 ± 3.12, P < 0.001). However, for all the patients with postoperative axial symptoms, the improvement rate of axial pain was significantly higher for patients without cervical kyphosis at the early-term follow-up (3 weeks) (P = 0.032), no significant differences were found at the medium-term (P = 0.554) and long-term follow-up (P = 0.902), and improvements of clinical symptom have no obvious difference at the last follow-up. CONCLUSIONS: Overall, preoperative axial neck pain and kyphosis could predict axial neck pain for patients undergoing multilevel anterior cervical decompression with fusion surgery, and recovery of cervical kyphosis may contribute to the long-term recovery of neural function, but may also suffer from risk of short-term axial pain, which could be reduced through moderate cervical curvature recovery.

The structures, water stabilities and photoluminescence properties of two types of iodocuprate(i)-based hybrids.

Although great progress has been made in hybrid iodocuprates(i) as lighting phosphors, the effects of aromatic and aliphatic structure directing agents (SDAs) on their water stability, structure and photoluminescence (PL) properties are still not clear. Herein, aromatic N-heterocyclic 1,2-di(4-pyridyl)ethylene (dpe), aliphatic N-heterocyclic 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu) and N-aminoethylpiperazine (app) were selected to be SDAs to construct two types of hybrid iodocuprates(i) via a facile in situ approach. Aromatic dpe-derived cations are successfully directed to form (Me2dpe)(CuI3) (1), (Me2dpe)n(Cu4I6)n (2), (Et2dpe)2(Cu6I10) (3), and (H2dpe)n(Cu2I4)n (4). Three of them contain unprecedented inorganic iodocuprate clusters or chains. The aliphatic N-heterocyclic dbu- and app-derivative cations are responsible for the formation of (Hdbu)n(Cu2I3)n (5) and (H3app)2(Cu2I6)·2I·2H2O (6), which contain a (Cu2I3)- chain and a (Cu2I6)4- binuclear cluster, respectively. For the first time, the influence mechanisms of the water stabilities of iodocuprate-based PL materials were disclosed, by analyzing the possible interactions between SDAs and water molecules. 1-2 are PL silent due to their "self-quenching effect". 3, 4 and5 exhibit bright red, orange and yellow solid-state PL emissions at room temperature respectively, originating from the charge transfer between inorganic iodocuprate species and organic N-heterocycles. The co-template approach leads to multiple charge transfers in 6, which features a tunable PL behavior from bluish green to white by varying the excitation light, and has a quantum yield up to 43% (the highest value among hybrid iodocuprates containing (Cu2I6)4- clusters). The comparative study not only helps us to rationally synthesize iodocuprate-based PL materials with enhanced performance, but also provides a new method to obtain wavelength-dependent PL materials.

Do alkyl groups on aromatic or aliphatic structure directing agents affect water stabilities and properties of hybrid iodoargentates?

Two types of in situ formed structure directing agents (SDAs) including aromatic triphenylphosphine (PPh3)- and aliphatic piperazine (H2pp)-derivative cations were used to synthesize five new hybrid iodoargentates, namely (EtPPh3)Ag3I4 (1, Et = ethyl), (n-PrPPh3)Ag3I4 (2, n-Pr = n-propyl), (i-PrPPh3)Ag5I6 (3, i-Pr = isopropyl), (Me4pp)0.5AgI2 (4, Me = methyl), and (H3app)2(Ag2I6)·2I·2H2O (5, app = N-aminoethylpiperazine). A comparative study of the two types of SDAs on the structures, stabilities and properties of hybrid iodoargentates was performed in detail. Structurally, except for (EtPPh3)+ and (n-PrPPh3)+, which both directly form (Ag3I4)- anionic chains in 1 and 2, three SDAs generate hybrid iodoargentates different from each other with inorganic anions ranging from a 0-D (Ag2I6)4- dimer to 1-D α-type (AgI2)- and (Ag5I6)- chains. With regard to the electronic structures, aromatic PPh3-derivative cations make noticeable contributions to the bottom of the conduction bands, while aliphatic pp-derivative cations make nearly no contribution to the frontier orbitals, clearly indicating their different ways to adjust the band gaps. With regard to stability, the decomposition temperatures of 1-3 in the range of 324-349 °C are noticeably higher than the values of 217 and 225 °C for 4 and 5. Furthermore, 1-4 exhibit good water stabilities, which is ascribed to the alkylation reactions precluding the formation of strong hydrogen bonds between alkylated SDAs and extraneous H2O molecules. Contrarily, the presence of typical hydrophilic [double bond, length as m-dash]NH2+, [triple bond, length as m-dash]NH+ and -NH3+ groups on the protonated (H3app)3+ cation makes 5 sensitive to water and a hydrolysis reaction occurs to generate a cubic AgI phase. Finally, 1-3 exhibit high photocatalytic efficiencies for the degradation of rhodamine B (RhB) dye in wastewater under visible light. All conclusions obtained here will help a lot in the synthesis of stable functional metal halide-based hybrids.