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One type of age-related macular degeneration (AMD), neovascular (nAMD), characterized by choroidal neovascularization (CNV), accounts for the majority of the severe central vision impairment associated with AMD. Endothelial cells (ECs) in direct contact with retinal pigment epithelial (RPE) cells are more prone to the pathological angiogenesis involved in CNV. Herein, we investigated the effect of crosstalk between RPE cells and choroidal endothelial cells (CECs) via the ANXA1/FPR2/NLRP3 inflammasome/pyroptosis axis on the development of choroidal neovascularization (CNV) in vitro and in vivo. ANXA1 expression and secretion from ARPE-19 cells were upregulated by hypoxia. FPR2 expression, especially on the plasma membrane, in HCECs was upregulated under hypoxic conditions. ANXA1 secreted from ARPE-19 cells inhibited NLRP3 inflammasome activation and NLRP3 inflammasome-mediated pyroptosis in HCECs by activating the FPR2/SHP2 axis. Moreover, ANXA1 secreted by ARPE-19 cells promoted behaviors of HCECs, including proliferation, migration, and tube formation, by activating the FPR2/SHP2 axis and inhibiting NLRP3 inflammasome-mediated pyroptosis. Inhibiting the upregulated ANXA1/FPR2/SHP2/NLRP3 inflammasome/pyroptosis axis decreased the volume of CNV. Our data suggest that the crosstalk between RPE cells and CECs via the ANXA1/FPR2/NLRP3 inflammasome/pyroptosis axis promotes CNV. This finding could identify a potential target for the prevention and treatment of CNV.

Wet age‐related macular degeneration (wAMD), characterized by choroidal neovascularization (CNV), is a leading cause of irreversible vision loss among elderly people in developed nations. Subretinal fibrosis, mediated by epithelial‐mesenchymal transition (EMT) of retinal pigment epithelium (RPE) cells, leads to unsuccessful anti‐vascular endothelial growth factor (VEGF) agent treatments in CNV patients. Under hypoxic conditions, hypoxia‐inducible factor‐1α (HIF‐1α) increases the stability and activation of p53, which activates microRNA‐34a (miRNA‐34a) transcription to promote fibrosis. Additionally, Klotho is a target gene of miRNA‐34a that inhibits fibrosis. This study aimed to explore the role of the HIF‐1α/p53/miRNA‐34a/Klotho axis in subretinal fibrosis and CNV. Hypoxia‐induced HIF‐1α promoted p53 stability, phosphorylation and nuclear translocation in ARPE‐19 cells (a human RPE cell line). HIF‐1α‐dependent p53 activation up‐regulated miRNA‐34a expression in ARPE‐19 cells following hypoxia. Moreover, hypoxia‐induced p53‐dependent miRNA‐34a inhibited the expression of Klotho in ARPE‐19 cells. Additionally, the HIF‐1α/p53/miRNA‐34a/Klotho axis facilitated hypoxia‐induced EMT in ARPE‐19 cells. In vivo, blockade of the HIF‐1α/p53/miRNA‐34a/Klotho axis alleviated the formation of mouse laser‐induced CNV and subretinal fibrosis. In short, the HIF‐1α/p53/miRNA‐34a/Klotho axis in RPE cells promoted subretinal fibrosis, thus aggravating the formation of CNV.

Parkinson's disease (PD) is a progressive neurodegenerative disorder. A common and disabling disease of the elderly, the standard dopamine replacement therapies do not arrest the ongoing neurodegeneration, thus calling for new treatment strategies. The present study aimed to clarify the functional relevance of the hypoxia inducible factor-1α (HIF-1α)/microRNA-128-3p (miR-128-3p) axis in hippocampal neurodegeneration in a PD mouse model obtained by intraperitoneal injection of MPTP. Targeting relationship between miR-128-3p and Axin1 was verified, so we probed the roles of Hif1a, miR-128-3p, and Axin1 in apoptosis of hippocampal neurons with gain- and loss-of function experiments using flow cytometry and TUNEL staining. We found that Axin1 was upregulated in hippocampal tissues and cells of the MPTP-lesioned mouse model of PD, while Hif1a and miR-128-3p were downregulated. Elevation of HIF-1α/miR-128-3p inhibited apoptosis of hippocampal neurons via Wnt/β-catenin signaling pathway activation due to the suppression of Axin1 in PD. In addition, forced overexpression of Hif1a could ameliorate motor dysfunction and pathological changes in the model. Collectively, activation of the HIF-1α/miR-128-3p axis could repress hippocampal neurodegeneration in MPTP-lesioned mice through an activated Wnt/β-catenin pathway due to Axin1 downregulation.

Background Study shows that signal transducer and activator of transcription 3 (STAT3) can increase the Warburg effect by stimulating hexokinase 2 in breast cancer and upregulate lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 in myeloma. STAT3 and pyruvate kinase M2 (PKM2) can also be activated and enhance the Warburg effect in hepatocellular carcinoma. Precancerous lesions are critical to human and rodent hepatocarcinogenesis. However, the underlying molecular mechanism for the development of liver precancerous lesions remains unknown. We hypothesized that STAT3 promotes the Warburg effect possibly by upregulating p-PKM2 in liver precancerous lesions in rats. Aim To investigate the mechanism of the Warburg effect in liver precancerous lesions in rats. Methods A model of liver precancerous lesions was established by a modified Solt-Farber method. The liver pathological changes were observed by HE staining and immunohistochemistry. The transformation of WB-F344 cells induced with N-methyl-N'-nitro-N-nitrosoguanidine and hydrogen peroxide was evaluated by the soft agar assay and aneuploidy. The levels of glucose and lactate in the tissue and culture medium were detected with a spectrophotometer. The protein levels of glutathione S-transferase-π, proliferating cell nuclear antigen (PCNA), STAT3, and PKM2 were examined by Western blot and immunofluorescence. Results We found that the Warburg effect was increased in liver precancerous lesions in rats. PKM2 and p-STAT3 were upregulated in activated oval cells in liver precancerous lesions in rats. The Warburg effect, p-PKM2, and p-STAT3 expression were also increased in transformed WB-F344 cells. STAT3 activation promoted the clonal formation rate, aneuploidy, alpha-fetoprotein expression, PCNA expression, G1/S phase transition, the Warburg effect, PKM2 phosphorylation, and nuclear translocation in transformed WB-F344 cells. Moreover, the Warburg effect was inhibited by stattic, a specific inhibitor of STAT3, and further reduced in transformed WB-F344 cells after the intervention for PKM2. Conclusion The Warburg effect is initiated in liver precancerous lesions in rats. STAT3 activation promotes the Warburg effect by enhancing the phosphorylation of PKM2 in transformed WB-F344 cells.

Neovascular age‐related macular degeneration (AMD), which is characterized by choroidal neovascularization (CNV), leads to vision loss. M2 macrophages produce vascular endothelial growth factor (VEGF), which aggravates CNV formation. The histone acetyltransferase p300 enhances the stability of spliced X‐box binding protein 1 (XBP1s) and promotes the transcriptional activity of the XBP1s target gene homocysteine inducible endoplasmic reticulum protein with ubiquitin‐like domain 1 (Herpud1). Herpud1 promotes the M2 polarization of macrophages. This study aimed to explore the roles of the p300/XBP1s/Herpud1 axis in the polarization of macrophages and the pathogenesis of CNV. Hypoxia‐induced p300 interacted with XBP1s to acetylate XBP1s in RAW264.7 cells. Additionally, hypoxia‐induced p300 enhanced the XBP‐1s‐mediated unfolded protein response (UPR), alleviated the proteasome‐dependent degradation of XBP1s and enhanced the transcriptional activity of XBP1s for Herpud1. The hypoxia‐induced p300/XBP1s/Herpud1 axis facilitated RAW264.7 cell M2 polarization. Knockdown of the p300/XBP1s/Herpud1 axis in RAW264.7 cells inhibited the proliferation, migration and tube formation of mouse choroidal endothelial cells (MCECs). The p300/XBP1s/Herpud1 axis increased in infiltrating M2‐type macrophages in mouse laser‐induced CNV lesions. Blockade of the p300/XBP1s/Herpud1 axis inhibited macrophage M2 polarization and alleviated CNV lesions. Our study demonstrated that the p300/XBP1s/Herpud1 axis in infiltrating macrophages increased the M2 polarization of macrophages and the development of CNV.

Purpose This study examined the role of the CSF1/CSF1Raxis in the crosstalk between choroidal vascular endothelial cells (CVECs) and macrophages during the formation of choroidal neovascularization (CNV). Methods Quantitative reverse transcriptase (QRT)-PCR, Western blot and ELISA measured the production and release of CSF1 from human choroidal vascular endothelial cells (HCVECs) under hypoxic conditions. Western blot detected CSF1 released from HCVECs under hypoxic conditions that activated the PI3K/AKT/FOXO1 axis in human macrophages via binding to CSF1R. Transwell migration assay, qRT-PCR, and Western blot detected the effect of CSF1 released from HCVECs on macrophage migration and M2 polarization via the CSF1R/PI3K/AKT/FOXO1 pathway. Incorporation of 5-ethynyl-20-deoxyuridine, transwell migration, and tube formation assays detected the effects of CSF1/CSF1R on the behaviors of HCVECs. Fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and immunofluorescence detected the effect of blockade of CSF1/CSF1R on mouse laser-induced CNV. Color fundus photograph, ICGA, and FFA detected CNV lesions in neovascular AMD (nAMD) patients. ELISA detected CSF1 and CSF1R in the aqueous humor of age-related cataract and nAMD patients. Results CSF1 released from HCVECs under hypoxic conditions activated the PI3K/AKT/FOXO1 axis in human macrophages via binding to CSF1R, promoting macrophage migration and M2 polarization via up-regulation of the CSF1R/PI3K/AKT/FOXO1 pathway. Human macrophages promoted the proliferation, migration, and tube formation of HCVECs in a CSF1/CSFR1-dependent manner under hypoxic conditions. CSF1/CSF1R blockade ameliorated the formation of mouse laser-induced CNV. CSF1 and CSF1R were increased in the aqueous humor of nAMD patients. Conclusions Our results affirmed the crucial role of CSF1/CSF1R in boosting the formation of CNV and offered potential molecular targets for the treatment of nAMD.

In this study, multi-walled carbon nanotubes (MWCNTs) with and without HNO3 pretreatment were employed as catalysts in catalytic ozonation for the removal of two pharmaceuticals and personal care products (PPCPs), ibuprofen and acetylsulfamethoxazole. The rate constants of MWCNTs in terms of direct ozone reaction (kD), initiation (kI), promotion (kP) and inhibition (kS) in the hydroxyl radical (OH˙) chain reactions were quantified. It was found that kD and kI increased with increasing solution pH and HNO3 concentration used in the pretreatment, while kP and kS showed the opposite trend. These trends could be attributed to the abundance of oxygen-containing functional groups including hydroxyl, carbonyl and carboxyl groups on the MWCNT surfaces resulting from HNO3 pretreatment. The removal of ibuprofen and acetylsulfamethoxazole was improved when MWCNTs were used as the catalyst due to enhanced OH˙ formation, which could be quantified using the determined rate constants. A kinetic model incorporating the rate constants of MWCNTs in the direct ozone reaction and OH˙ chain reactions can be used to predict the removal of contaminants in catalytic ozonation.

BACKGROUND This study aimed to investigate the effect of cobalt transporter II gene (rs1801198, rs2301957, rs9606756) polymorphism on serum homocysteine level and its correlation with young and middle recurrent cerebral infarction. METHODS A total of 348 young and middle-aged patients with cerebral infarction admitted to The Third Affiliated Hospital of Qiqihar Medical University from January 2017 to March 2018 were enrolled. The patients were divided into recurrent and non-recurrent groups according to follow-up. DNA was extracted from the peripheral blood of patients, and the DNA samples were genotyped by IlluminaBeadArray technology to detect the gene polymorphisms of cobalt transporter II (TCN2) sites (rs1801198, rs2301957, rs9606756), and the homocysteine (hcy) level was determined by cyclic enzymatic method. VitB12 and folate levels were measured by chemiluminescence immunoassay, and holo transcobalamin (holoTC) expression levels were detected by enzyme-linked immunosorbent assay. RESULTS The frequency of alleles of rs9606756 mutation in the recurrent group was higher than that in the non-recurrent group (P

Choroidal neovascularization (CNV), a feature of neovasular age-related macular degeneration (AMD), acts as a leading cause of vision loss in the elderly. Shikonin (SHI), a natural bioactive compound extracted from Chinese herb radix arnebiae, exerts anti-inflammatory and anti-angiogenic roles and also acts as a potential pyruvate kinase M2 (PKM2) inhibitor in macrophages. The major immune cells macrophages infiltrate the CNV lesions, where the production of pro-angiognic cytokines from macrophage facilitates the development of CNV. PKM2 contributes to the neovascular diseases. In this study, we found that SHI oral gavage alleviated the leakage, area and volume of mouse laser-induced CNV lesion and inhibited macrophage infiltration without ocular cytotoxicity. Moreover, SHI inhibited the secretion of pro-angiogenic cytokine, including basic fibroblast growth factor (FGF2), insulin-like growth factor-1 (IGF1), chemokine (C-C motif) ligand 2 (CCL2), placental growth factor and vascular endothelial growth factor (VEGF), from primary human macrophages by down-regulating PKM2/STAT3/CD163 pathway, indicating a novel potential therapy strategy for CNV.

Background: During vitrectomy, a relatively high level of accuracy is required when using retinal laser energy, which is difficult to control in the presence of subretinal fluid and other conditions. We explored the clinical effects of retinal pigment epithelium (RPE)photocoagulation in closing retinal breaks and preventing hypotony during vitrectomy. We describe the possible indications of RPE photocoagulation. Methods: This was a prospective, non-random, uncontrolled case series study. We recruited 20 patients, with retinal detachment in 20 eyes. In this study, RPE photocoagulation was performed under the detached retina and retinal holes. RPE laser photocoagulation was performed in 3-4 rows at the edge of the periphery around the hole and the tear, replacing the traditional retinal photocoagulation and closing part or all of the retinal break. The energy of RPE photocoagulation was 100-150mJ for 120-200ms to seal the breaks, and the same energy but little gaps for the RPE without covering of retina. Results: After vitrectomy, in 19 eyes, there was a visible pigmentation reaction around the hole and tear, except for 1 eye the retinal hole located in the myelinated nerve fibre area. The mean best-corrected visual acuity (BCVA) at 6 months after surgery was significantly higher than that before surgery (p=0.002). At the last follow-up, the mean BCVA remained significantly higher than that before surgery (p=0.001).There was no significant difference in BCVA between the 6th month and the last follow-up (p=0.806).The thickness of the neurosensory layer in RPE photocoagulation and retinal photocoagulation area at 1 month after surgery was 216.33±54.42μm and 87.67±34.65μm, respectively. By the end of the follow-up, there were no serious complications, and the retinas of all 20 eyes were reattached. No hypotony occurred after surgery. Conclusions: The effects of RPE photocoagulation and retinal photocoagulation are similar in closing retinal breaks. The RPE laser sealed the retinal breaks and did not damage the neurosensory layer, but still caused pigmentation formation on the RPE, resulting in adhesion between the neurosensory layer and the RPE layer. Laser photocoagulation could be considered as comparable to glue instead of welding when closing the retinal breaks. Trial registration ChiCTR1900021504,2019-02-24.

Recently, it has been demonstrated that microRNA-137 (miR-137) plays a vital role in the induction of oxidative stress of neurons in Parkinson’s disease (PD). Herein, the study aimed to investigate the effects of serum exosomal miR-137 on oxidative stress injury of neurons in PD. Microarray analysis was adopted to screen the PD-related differential expressed genes and predict the interaction between OXR1 and miR-137 in PD. It was found that OXR1 was down-regulated while miR-137 was up-regulated in PD. Additionally, miR-137 targeted OXR1 and negatively regulated its expression. Mouse and neuron models of PD were established to mimic the pathological changes, especially oxidative stress injury induced by PD. The significance of miR-137 and OXR1 in oxidative stress injury was investigated in neuron model of PD using gain- and loss-of-function approaches. The obtained data exhibited that inhibition of miR-137 or up-regulation of OXR1 ameliorated PD-induced oxidative stress injury, reduced pole-climbing time, but increased score for traction test as well as promoted viability and decreased apoptosis of neurons in PD model, accompanied with decreased MDA content and ROS levels, and increased SOD levels. Furthermore, PD mice were injected with serum-derived exosomes or neurons in PD models were exposed to exosomes derived from serum of PD mice. Loss-of-function experiments using miR-137 antagomir exhibited that inhibition of exosomal miR-137 ameliorated PD-induced oxidative stress injury in vitro, reduced pole-climbing time but increased score for traction test in vivo. Collectively, down-regulation of exosomal miR-137 alleviates oxidative stress injury in PD by up-regulating OXR1.

Protective effect of edaravone on blood-brain barrier (BBB) in experimental cerebral infarction rats was investigated. SD rats were prepared as the permanent middle cerebral artery occlusion model and randomly divided into 4 groups: cerebral infarction model group, edaravone low, medium and high dose groups. Healthy rats only for operation and no filament were selected as the sham operation control group. Rats in the cerebral infarction model group and the control group were given normal saline, and those in the edaravone low, medium and high dose groups were given edaravone 10, 15 and 20 mg/kg, respectively. The survival status, the body weight and neurological function score before and after treatment, the brain water content and the permeability of the blood-brain barrier after treatment were measured. The expression levels of NFE2-related factor 2 (NRF2) and hemeoxygenase 1 (HO-1) in rat brain tissue were detected by western blotting. Levels of peripheral blood malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) were detected by ELISA. The state of the rats in three edaravone groups was improved compared with that of the cerebral infarction group. Compared with the cerebral infarction model group, the body weight was significantly increased after treatment and the neurological function score, brain tissue water content and BBB permeability were significantly decreased in three edaravone groups (P

Metallic germanium is a promising anode material in secondary lithium-ion batteries (LIBs) due to its high theoretical capacity (1623 mAh/g) and low operating voltage, coupled with the high lithium-ion diffusivity and electronic conductivity of lithiated Ge. Here, the lithiation mechanism of micron-sized Ge anodes has been investigated with X-ray diffraction (XRD), pair distribution function (PDF) analysis, and in-/ex-situ high-resolution 7Li solid-state nuclear magnetic resonance (NMR), utilizing the structural information and spectroscopic fingerprints obtained by characterizing a series of relevant LixGey model compounds. In contrast to previous work, which postulated the formation of Li9Ge4 upon initial lithiation, we show that crystalline Ge first reacts to form a mixture of amorphous and crystalline Li7Ge3 (space group P3212). Although Li7Ge3 was proposed to be stable in a recent theoretical study of the Li–Ge phase diagram (Morris, A. J.; Grey, C. P.; Pickard, C. J. Phys. Rev. B: Condens. Matter Ma...

Age-related macular degeneration (AMD) is a leading cause of vision loss in the elderly and is attributed to choroidal neovascularization (CNV), which is a feature of wet AMD. The hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF)/VEGF receptor 2 (VEGFR2) pathway contributes to the pathogenesis of CNV. M1-type macrophages/microglia secrete interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α), facilitating the development of CNV. Epigallocatechin-3-gallate (EGCG) is a kind of polyphenol in green tea that exerts anti-inflammatory and antiangiogenic effects. In this study, a prodrug of EGCG (pro-EGCG) alleviated mouse laser-induced CNV leakage and reduced CNV area by down-regulating HIF-1α/VEGF/VEGFR2 pathway; M1-type macrophage/microglia polarization; as well as endothelial cell viability, proliferation, migration and tube formation, indicating a novel potential therapy for AMD.

Conversion materials for lithium ion batteries have recently attracted considerable attention due to their exceptional specific capacities. Some metal fluorides, such as CuF2, are promising candidates for cathode materials owing to their high operating potential, which stems from the high electronegativity of fluorine. However, the high ionicity of the metal–fluorine bond leads to a large band gap that renders these materials poor electronic conductors. Nanosizing the active material and embedding it within a conductive matrix such as carbon can greatly improve its electrochemical performance. In contrast to other fluorides, such as FeF2 and NiF2, good capacity retention has not, however, been achieved for CuF2. The reaction mechanisms that occur in the first and subsequent cycles and the reasons for the poor charge performance of CuF2 are studied in this paper via a variety of characterization methods. In situ pair distribution function analysis clearly shows CuF2 conversion in the first discharge. Howev...

During the course of fermentation of Chinese sauerkraut, it would produce nitrite. However, the presence of nitrite made Chinese sauerkraut cause edible security problem. In this study, the change regularity of nitrite during natural fermentation was analysed, and the best edible time was determined. The results showed that content of nitrite was increased in the early stage of fermentation, after reaching to a peaking content, it reduced significantly to a low level, and then it changed little at the mature stage. That is to say, it could guarantee the edible security when Chinese sauerkraut matured.

Na-ion batteries represent an effective energy storage technology with slightly lower energy and power densities but potentially lower material costs than Li-ion batteries. Here, we report a new polyanionic intercalation cathode material of an unusual chemical class: sidorenkite (Na3MnPO4CO3). This carbonophosphate compound shows a high discharge capacity (∼125 mAh/g) and specific energy (374 Wh/kg). In situ X-ray diffraction measurement suggests that sidorenkite undergoes a solid solution type reversible topotactic structural evolution upon electrochemical cycling. Ex situ solid state NMR investigation reveals that more than one Na per formula unit can be deintercalated from the structure, indicating a rarely observed two-electron intercalation reaction in which both Mn2+/Mn3+ and Mn3+/Mn4+ redox couples are electrochemically active.

The effect of conductive carbon type and loading was examined for the iron phthalocyanine (FePc) cathode in primary lithium (Li) batteries. The use of nano graphene platelets (NGPs) as a conductive carbon was shown to increase the discharge capacity by a factor of at least 2.5 compared to typical carbon blacks and vapor grown carbon fibers. Discharge capacities of up to 2050 mAh g −1 FePc, corresponding to the insertion of 43 Li + , were obtained for FePc based cathodes with 25% NGPs. This is the highest cathode capacity reported in literature to our knowledge. Cathodes with 10% NGP still demonstrated reasonable capacities. Electrolyte solutions based on propylene carbonate demonstrated higher discharge voltages than those with the 1.2 M lithium tetrafluoroborate in γ-butyrolactone and 1,2-dimethoxyethane (1:1 by volume).

Sour pickled cabbage is a traditional Chinese food, which was made with fresh vegetables such as cabbage. Because of its naturally fermentation, a lot of lactic acid bacteria are riched in it. However, the traditional naturally fermented sour pickled cabbage were home-made in China, because of the difference of raw material, processing, formula and other factors, the flavor, nutrition and safety of them varied significantly, in order to investigate the influencing factors affected the flavor, quality and security of the naturally fermented sour pickled cabbage, and discuss the relationship between chemical composition and the flavor, quality and security, the acidity, total sugar, nitrite, protein and sodium chloride levels of 5 naturally fermented sour pickled vegetables by means of acid-base titration method, the direct titration, the hydrochloric acid naphthalene ethylenediamine kieldahl method, the indirect precipitation titration method respectively. The results were showed as follow, the acidity were between 0.283% and 0.891%, the total sugar content were between 3.96% to 4.37%, the nitrate content were 0.167 g/kg to 0.267 g/kg, the protein content were between 0.0169% and 0.0218%, the sodium chloride content were between 0.412% and 0.447% respectively.

Aims To investigate the protective effects of 17β-estradiol postconditioning against ischemia/reperfusion (I–R)-induced gastric mucosal injury in rats. Main methods The animal model of gastric ischemia/reperfusion was established by clamping of the celiac artery for 30 min and reperfusion for 30 min, 1 h, 3 h, 6 h, 12 h or 24 h. 17β-estradiol at doses of 5, 50 or 100 μg/kg (rat) was administered via peripheral veins 2 min before reperfusion. In a subgroup of rats, the estrogen receptor antagonist fulvestrant (Ful, 2 mg/kg) was intravenously injected prior to 17β-estradiol administration. Histological and immunohistochemical methods were employed to assess the gastric mucosal injury index and gastric mucosal cell apoptosis and proliferation. The malondialdehyde (MDA) concentration, superoxide dismutase (SOD) activity, xanthine oxidase (XOD) activity and hydroxyl free radical (–OH) inhibitory ability were determined by colorimetric assays. Subsequently, the expression of Bcl-2 and Bax in rat gastric mucosa was examined by western blotting. Key findings 17β-estradiol dose-dependently inhibited gastric I–R (GI–R) injury, and 17β-estradiol (50 μg/kg) markedly attenuated GI–R injury 1 h after reperfusion. 17β-estradiol inhibited gastric mucosal cell apoptosis and promoted gastric mucosal cell proliferation in addition to increasing SOD activity and –OH inhibitory ability and decreasing the MDA content and XOD activity. The Bax protein level increased 1 h after GI–R and was markedly reduced by intravenous administration of 17β-estradiol. In contrast, the level of Bcl-2 protein decreased 1 h after GI–R and was restored to normal levels by intravenous administration of 17β-estradiol. These effects of 17β-estradiol were inhibited by pretreatment with fulvestrant. Significance 17β-estradiol postconditioning should be investigated further as a possible strategy against gastric mucosal injury.

The thermodynamic mixing properties of the pyrope-grossular solid solution show large deviations from ideality, which could be partly related to Ca-Mg order/disorder. In this study, synthetic pyrope-grossular garnets with X_(Mg) = 1.00, 0.91, 0.75, 0.50, 0.24, 0.10, and 0.00 are observed using ^(17)O 3QMAS, ^(27)Al MAS, and ^(29)Si MAS NMR to examine Ca-Mg order/disorder behavior and crystal chemical variations. The ^(17)O 3QMAS NMR spectra show four distinct resonances, assigned to four different local oxygen coordination environments; two resemble end-member garnets (oxygen bonded to two Mg or two Ca) and two are intermediate (oxygen bonded to one Ca and one Mg), indicating that there are two distinct bond distances for the Mg-O and/or Ca-O bonds through the entire solid solution. Noticeable changes in the NMR peak position for two of the oxygen sites suggest that as X_(Mg) increases, the longer Ca-O bond shortens. The relative areas for the different oxygen sites are close to those predicted using a model of random Ca/Mg mixing. The maximum allowed reduction in configurational entropy from first neighbor Ca-Mg ordering is insignificant relative to other configurational entropy reductions and excess vibrational entropy. These conclusions are not inconsistent with published theoretical calculations suggesting some Ca-Mg ordering that involves correlations beyond the first neighbor, as suggested by published theoretical calculations. Even at 18.8 Tesla, the ^(27)Al MAS NMR spectra do not resolve different local Al sites with varying combinations of X cation neighbors. The ^(29)Si MAS NMR spectra have resonance broadening, probably caused by the addition of 0.15 wt% Fe_2O_3 in the synthetic samples, and are consistent with published results suggesting a small degree of Ca-Mg ordering that is not reflected in the ^(17)O NMR spectra.

We present here triple-quantum, magic-angle spinning (3QMAS) NMR spectra for 17O in a SiO2–GeO2 binary glass, and for two sodium germanosilicate glasses, all with Si/Ge ratios of 1. In the binary germanosilicate, three NMR peaks are partially resolved, and correspond to the three types of bridging oxygens, Si–O–Si, Si–O–Ge, and Ge–O–Ge. Peak areas indicate that the relative abundances of these species are close to those expected for random mixing of the Si and Ge in the network. In a sodium germanosilicate glass with a relatively low Na content (Na2O ≈ 8 mol%), the spectra demonstrate the formation of significant fractions of both nonbridging oxygens bonded to Si, and of oxygens bonded to Ge in five- or six-coordination. At higher Na content (Na2O ≈ 31%), most or all Ge is four-coordinated and network modification is dominated by the formation of NBO on Si and on Ge. Models of physical properties of alkali germanosilicates, in which modifier oxides are distributed between the Si and Ge components of the network in proportion to the Si/Ge ratio, are thus supported, as is extensive mixing of Si and Ge.

The densities and viscosities of silicate melts depend strongly on pressure, in part because of potentially measurable structural rearrangements. In an attempt to further understand these changes and how they affect macroscopic properties, we have used 27Al MAS NMR to determine the coordination of the Al cations in a series of aluminosilicate glasses quenched from melts at pressures of 2 to 8 GPa, have measured the glass densities, and have applied an in-situ falling sphere method to measure melt viscosities at high pressure. Spectra from these four- and five-component glasses show increasing Al coordination with increasing pressure and with increasing average field strength of the modifier cation, as was previously reported for simpler compositions. These data also indicate that when multiple modifier cations are present (e.g., Ca and K), the Al coordination is lower than what would be expected from linear combinations of the appropriate aluminosilicate end-members. The viscosity of Ca3Al2Si6O18 melts, measured using a falling sphere method that combines multianvil techniques with synchrotron X-ray radiography, may reach a minimum at a pressure below 6 GPa. A quasi-thermodynamic approach using equilibrium constants for the reactions that generate high-coordinated Al suggests that this pressure may be related to a maximum in the concentration of five-coordinated Al. These results further support the concept that pressure-induced network structural transitions have direct implications for the macroscopic properties of high-pressure melts.

The 17 O NMR spectra of glasses quenched from melts at high pressure are often difficult to interpret due to overlapping peaks and lack of crystalline model compounds. High-pressure aluminosilicate glasses often contain significant amounts of [5] Al and [6] Al, thus these high-pressure glasses must contain oxygen bonded to high-coordinated aluminum. The 17 O NMR parameters for the minerals jadeite, pyrope, grossular, and mullite are presented to assist interpretation of glass spectra and to help test quantum chemical calculations. The 17 O NMR parameters for jadeite and grossular support previous peak assignments of oxygen bonded to Si and high-coordinated Al in high-pressure glasses as well as quantum chemical calculations. The oxygen tricluster in mullite is very similar to the previously observed tricluster in grossite (CaAl 4 O 7 ) and suspected triclusters in glasses. We also present 27 Al NMR spectra for pyrope, grossular, and mullite.

A systematic study on the structure and function of Glucose-6-phosphate dehydrogenase (G6PD) variations was carried out in China. A total of 155,879 participants were screened for G6PD deficiency by the G6PD/6PGD ratio method and 6,683 cases have been found. The prevalence of G6PD deficiency ranged from 0 to 17.4%. With informed consent, 1,004 cases from 11 ethnic-based groups were subjected to molecular analysis. Our results showed the followings: (1) The G6PD variants are consistent across traditional ethnic boundaries, but vary in frequencies across ethnic-based groups in Chinese population, (2) The G6PD variants in Chinese population are different from those in African, European, and Indian populations, (3) A novel G6PD-deficiency mutation, 274C--T, has been found, and (4) Denaturing high performance liquid chromatography is of great advantage to detecting G6PD-deficient mutations for diagnosis and genetic counseling. Moreover, functional analysis of the human G6PD variants showed the following: (1) The charge property, polarity, pK-radical and side-chain radical of the substituting amino acid have an effect on G6PD activity, (2) The G6PDArg459 and Arg463 play important roles in anchoring NADP+ to the catalytic domain to maintain the enzymatic activity, and (3) The sequence from codon 459 to the carboxyl terminal is essential for the enzymatic function.

Aluminum is an important minor constituent of a number of high-pressure mantle silicates in which it substitutes for octahedrally coordinated silicon. In several cases, its solid solution may be linked to the presence of oxygen vacancies; in others, to charge balance with H + . Here we present new data from high-resolution, high-field (18.8 Tesla) 27 Al NMR of aluminous stishovite and of a non-stoichiometric perovskite with nominal composition MgSi 0.95 Al 0.05 O 2.975 . For the stishovite, we characterize the local structure of the symmetrical, octahedral site for Al. These results, combined with 27 Al{ 1 H} REDOR NMR, are consistent with hypothesized H + charge balance, although the presence of a significant fraction of randomly distributed oxygen vacancies could remain undetected. As in a recent previous study of a related perovskite composition, the observed ratio of Al at symmetrical octahedral B sites to that of Al at large, central A sites is about 2:1, indicating the presence of oxygen vacancies to account for charge neutrality in this phase. Such vacancies are not preferentially associated with the Al octahedra, however, suggesting a random distribution in the structure.

The variation of the structure of E-glass with fictive temperature has been examined with high resolution, multinuclear (11B, 27Al, 29Si, 17O, and 19F) MAS NMR. The previously observed decrease in 4-coordinated boron with increasing fictive temperature is confirmed and, for the first time, is directly correlated with an increase in non-bridging oxygens. An increase in 5-coordinated Al is also observed, and is linked to an increase in association of F with Al at higher fictive temperature.

O-17 enriched calcium and potassium aluminoborosilicate glasses with compositions similar (or analogous) to commercial E-glass were made and studied by 11B, 27Al and 17O NMR in order to explore the network speciation and mixing. Fractions of non-bridging oxygens associated with silicon and boron can be obtained simply from 17O magic angle spinning (MAS) NMR, while bridging oxygen populations result from complete peak assignment of high-resolution 17O triple quantum magic angle spinning (3QMAS) NMR spectra. Dramatic differences between the two samples in boron and oxygen speciation demonstrate a large effect of the charge of the modifier cation on mixing behavior and on the stabilization of non-bridging oxygens. The observed oxygen speciation is compared with that calculated from two models: random mixing of Si, B, and Al, and mixing with avoidance of linkages between tetrahedral aluminum and tetrahedral boron groups. Mixing of B and Al in the K-containing glass tends to follow the latter, while the network speciation in the Ca-containing glass is closer to the random model. The effects of Al and Si on boron speciation are discussed, and indicate that the maximum fractions of four-coordinated boron observed in a wide range of glass compositions are closely related to tetrahedral B and Al ‘avoidance’. A modified ‘Dell and Bray’ model is proposed which seems to accurately approximate boron speciation in many alkali aluminoborosilicate glasses. The higher field strength modifier cation (Ca2+ vs. K+) promotes the formation of non-bridging oxygen, trigonal over tetrahedral boron, and at least minor amounts of five-coordinated aluminum.

In a series of sodium aluminoborate glasses, we have applied triple-quantum magic-angle spinning (3QMAS) 17O NMR to obtain high-resolution information about the connections among various network structural units, to explore the mixing of aluminum and boron species. Oxygen-17 3QMAS spectra reveal changes in connectivities between AlO4 ([4]Al), AlO5 and AlO6 ([5,6]Al), BO3 ([3]B) and BO4 ([4]B) units, by quantifying populations of bridging oxygens such as Al-O-Al, Al-O-B and B-O-B and of non-bridging oxygens. Several linkages such as [4]Al-O-[4]Al and three-coordinated oxygen associated with [5,6]Al in Al-O-Al, [4]Al-O-[4]B, [4]Al-O-[3]B and [5,6]Al-O-[3]B in Al-O-B as well as [4]B-O-[3]B and [3]B-O-[3]B in B-O-B can be distinguished for the first time. The fractions of these linkages were calculated from models of random mixing and of mixing with maximum avoidance of tetrahedral-tetrahedral linkages. The results suggest that the structure of all of glasses in this study is well approximated by the latter model. However, the energetic "penalty" for formation of [4]Al-O-[4]B may be somewhat less than for [4]Al-O-[4]Al and [4]B-O-[4]B. In general, the new results presented here are similar to those obtained on glasses in this system by 27Al{11B} REDOR NMR (J. Phys. Chem. B 104 (2000) 6541), but provide considerably more detail on network connectivity and ordering schemes.

Chlorine-35 magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra were collected at 14.1 and 18.8 Tesla fields to determine the atomic scale structural environments of the chloride ions in anhydrous and hydrous silicate and aluminosilicate glasses containing 0.2 to 0.7 wt% Cl. NMR peaks are broad and featureless, but are much narrower than the total chemical shift range for the nuclide in inorganic chlorides. Peak widths are primarily due to quadrupole interactions and to a lesser extent to chemical shift distributions. Peak positions are quite different for the Na- and Ca-containing glasses, suggesting that most Cl − coordination environments contain network modifier cations. Comparison of peak positions and shapes for silicate and aluminosilicate glasses containing either Na or Ca suggests that there is no obvious contribution from Cl − bonded to Al, and relative quantitation of peak areas indicates that there is no systematic undercounting of 35 Cl spins in the aluminous vs. the Al-free samples. In Ca-Na silicate glasses with varying Ca/(Ca + Na), the mixed-cation glasses have intermediate chemical shifts between those of the end members, implying that there is not a strong preference of either Ca 2+ or of Na + around Cl − . Hydrous Na-aluminosilicate glasses with H 2 O contents up to 5.9 wt% show a shift to higher frequency NMR signal with increasing H 2 O content, while the quadrupole coupling constant ( C Q ) remains constant at ∼3.3 MHz. However, the change in frequency is much smaller than that expected if H 2 O systematically replaced Na + in the first-neighbor coordination shell around Cl − . A series of hydrous Ca-aluminosilicate glasses with H 2 O contents up to 5.5 wt% show no shift in NMR signal with increasing H 2 O content. The C Q remains constant at ∼4.4 MHz, again suggesting no direct interaction between Cl − and H 2 O in these samples.

Two of the most important structural controls on the properties of borosilicate glasses and glass melts are the variation between three- and four-coordination of network-forming boron cations, and the extent of mixing of Si and B. The effects of composition on these key parameters are relatively well studied. However, proposed mechanisms could be better constrained by testing with another, independent parameter that can also strongly affect the network. Here we present some of the first quantitative structural data on the effects of high pressure on the network structure of a sodium borosilicate glass. Using high-resolution 11 B and 17 O NMR on a sample melted at 5 GPa, we demonstrate that the formation of tetrahedral boron from trigonal boron is indeed closely coupled to the conversion of non-bridging to bridging oxygens. The increased fraction of tetrahedral boron at high pressure also causes increased mixing of boron and silicate structural units, as oxygens bridging between two BO 4 groups are energetically relatively unfavorable.

Several glasses were synthesized to explore cation ordering at fluorine sites in silicate and aluminosilicate glasses. Utilizing 19F NMR, we found a significant (at least ∼30% of the total intensity) amount of the fluorine signal to be due to F–Mg(n) (fluorine with an unknown number of exclusively Mg2+ nearest neighbors) bonding in the Mg-aluminosilicates. By combining this with previous data on Ca- and Ba-aluminosilicate glasses, we demonstrated a clear trend of an increasing amount of F–M(n) type bonding with increasing field strength of the network modifying cation. This indicates that the higher field strength cations can more effectively compete with Al3+ for fluorine bonds. The mixed-modifier (Na,La)-silicate glasses have primarily F–M(n) type bonding, with a pronounced preference for bonding to the higher field strength La3+ over Na+. In addition, Si–F bonding was found in the (Na,La)-silicate glasses at a level (∼2% of the total intensity) comparable to that found in other silicate glasses, suggesting that Si–F bonding is consistently present in silicate glasses. The (Na,La)-silicate glasses also had unusually short spin–spin relaxation times, suggesting short (similar to crystalline fluorides) fluorine–fluorine distances in environments associated with La3+.

We report new, high-resolution solid state 27Al NMR data for two members of the magnetoplumbite group of structures, strontium hexaluminate (SrAl12O19, “SA6”) and calcium hexaluminate (CaAl12O19, “CA6,” synthetic hibonite), acquired at 14.1 and 18.8 T fields. The high-field data allow, for the first time, the accurate observation of the NMR signal from the Al(2) sites, which have been previously described as “pentacoordinate” but which appear instead to be very distorted tetrahedra, which give rise to 27Al isotropic chemical shifts of about 57 ppm and nuclear quadrupolar coupling constants of about 21 MHz. This finding is fully consistent with “split-atom” refinements of these crystal structures, in which the most probable position of the Al atom is displaced away from the average trigonal pyramidal site center, along the crystallographic 3-fold axis. The NMR data also demonstrate, however, that the “splitting” is the result of static, not dynamical, disorder among these sites.

In several series of sodium borosilicate glasses, we have applied triple-quantum magic-angle spinning (3QMAS) 11B and 17O NMR to obtain high-resolution information about short-range structure and the connections among various network structural units and their variations with composition. Oxygen-17 3QMAS spectra reveal changes in connectivities between silicate and BO3 ([3]B) and BO4 ([4]B) units, by quantifying populations of bridging oxygens such as Si−O−Si, Si−O−[3]B, Si−O−[4]B, [3]B−O−[3]B, and [4]B−O−[3]B and of nonbridging oxygens. Boron-11 MAS and 3QMAS at a magnetic field of 14.1 T allow proportions of several borate units to be determined, including [3]B in boroxol ring and nonring sites and [4]B with two, three, and four Si neighbors. By combining the 11B and 17O NMR results, detailed information on Si/B mixing in sodium borosilicates can be derived. Our results shows that [4]B is strongly associated with silicate units, nonring [3]B undergoes random mixing and ring [3]B tends to connect to bora...

In several series of lithium, sodium, and potassium borosilicate glasses whose compositions traverse known regions of liquid–liquid phase separation, we have applied triple-quantum magic-angle spinning (3QMAS) 11B and 17O NMR to obtain high-resolution information about short-range structure and connections among various network structural units, and their variation with composition and thermal history. Oxygen-17 3QMAS spectra reveal changes in connectivities between silicate and BO3 ([3]B) and BO4 ([4]B) units, by quantifying populations of bridging oxygens such as B–O–B, Si–O–B and Si–O–Si, and of non-bridging oxygens. [3]B–O–Si and [4]B–O–Si as well as [3]B–O–[3]B and [4]B–O–[3]B linkages can be distinguished. 11B MAS and 3QMAS at a magnetic field of 14.1 T allow proportions of several borate units to be determined, including [3]B in boroxol ring and non-ring sites and [4]B with 3 versus 4 Si neighbors. By combining the 11B and 17O NMR results, detailed information on Si/B mixing in sodium borosilicates can be derived, showing, for example, that [4]B and non-ring [3]B tend to mix with silicate units, while ring [3]B is mainly connected to borate groups. In a preliminary study of the effects of varying alkali cation, potassium-containing glasses are similar to those in the sodium borosilicate system, but a lithium borosilicate seems to exhibit considerably greater chemical heterogeneity. In annealing experiments that converted an optically clear to obviously phase-separated glasses, the ratio of [3]B to [4]B does not change significantly, but part of the non-ring [3]B converts to ring [3]B as the degree of unmixing increases.

Disordering of Si and Al in natrolite, scolecite, mesolite, and gonnardite was investigated with 29 Si and 27 Al magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The results indicate that with the exception of one sample of natrolite (from San Benito County, California), the natrolite, mesolite, and scolecite samples studied all exhibit small degrees ( 29 Si MAS NMR spectra and mathematical relations based on Al avoidance were used to calculate Si and Al occupancies across the tetrahedral sites in these minerals. Configurational entropies arising from Si-Al disorder in natrolite, mesolite, and scolecite can add an addition 1–2% [up to 11 J/(mol·K)] to the total entropies of these phases at 298.15 K, whereas it may add as much as 7% to that of gonnardite [up to 27.7 J/(mol·K)]. These results also concur with previous observations of a gap in Si-Al disordering between orthorhombic and tetragonal natrolite samples and suggest that the state of disorder in natrolite is a function of temperature. The 29 Si MAS NMR spectrum of gonnardite is consistent with a disordered natrolite framework structure, and not an intergrowth of thomsonite and natrolite structural domains.

Despite the importance of the chloride ion in magmas and the fluids that separate from them, very little is known about atomic-scale structural environments for Cl− in silicate glasses. We present here the first solid-state 35Cl NMR data for Cl in silicate and aluminosilicate glasses, made possible by the availability of very high (14.1 to 18.8 Tesla) magnetic fields. We find that 35Cl has a wide range in chemical shifts that correlate well with cation-Cl distance and thus contain considerable structural information. In general, Cl is coordinated primarily by network-modifying alkali or alkaline earth cations, and we see no evidence for Al-Cl bonding.

A variety of NMR interactions have been characterized by solid-state NMR spectroscopy in potassium heptafluoroniobate, K2NbF7, which contains fluorine atoms arranged about a central niobium atom in a heptacoordinate, capped trigonal prism arrangement. Simulations of 93Nb MAS NMR spectra acquired at 11.7 T and at high spinning speeds (35 kHz) yielded the nuclear quadrupole coupling constant, CQ(93Nb), the asymmetry parameter, η, and the isotropic chemical shift, δiso. From the analysis of 93Nb NMR spectra of stationary samples of K2NbF7, the niobium chemical shielding anisotropy (span, Ω = 200 ppm) and the relative orientation of the electric field gradient (EFG) and chemical shielding (CS) tensors were determined. The 93Nb MAS NMR spectra acquired at lower spinning speeds, where the spinning sidebands are not separated from the centerband, were also simulated by using an efficient time propagation algorithm based on Floquet theory. The CQ(93Nb) is seen to increase with decreasing temperature, varying from...

Three resonances corresponding to the three crystallographically distinct fluorine sites were resolved in the high-resolution 19 F MAS spectrum of chiolite (Na 5 Al 3 F 14 ) collected at a field strength of 19.6 T and at a spinning speed of 40 kHz. In contrast, only one broad resonance is observed in the 19 F MAS NMR spectrum of the isostructural compound Na 5 W 3 O 9 F 5 . Thus, a combination of 19 F MAS, 19 F → 23 Na CP, and 23 Na → 19 F HETCOR NMR experiments was required to resolve the resonances from the different local environments in this compound. Fluorine was shown to preferentially occupy two of the three anion sites.

Five new compounds in the AxMTeO6 family were prepared and structurally characterized: Li2GeTeO6, Na2TiTeO6, Na2SnTeO6, and two forms of Na2GeTeO6. All compounds are layered structures based on various stacking arrangements of MTeO2−6 layers. The structures of BaGeTeO6 and SrGeTeO6 were also determined. The former compound was found to contain Ba2+ in trigonal prismatic coordination, in agreement with previous literature reports, while SrGeTeO6 contains Sr2+ in octahedral coordination and is not isostructural with BaGeTeO6 as was previously reported. Structural characterizations were carried out using a variety of tools, including Rietveld refinements of X-ray and neutron powder diffraction data, solid-state MAS–NMR, and Raman and infrared spectroscopy. With the exception of M=Ti4+, the MTeO2−6 layers show a high degree of order between M4+ and Te6+ cations within the layers, but the stacking faults are generally present, which results in a significant decrease in the long-range ordering of the M4+ and Te6+ cations in the third dimension. The compound K2−xNaxTiTeO6 was prepared by reacting Na2TiTeO6 and KNO3 under hydrothermal conditions at 200°C in a Teflon-lined Parr bomb. This compound adopts a pyrochlore structure with cell edge 10.18 A. NMR measurements indicate a disordered Ti/Te distribution.

Negative cross-peaks have been observed in the 19 F 2-D magnetization-exchange MAS NMR spectra of Ba 2 MoO 3 F 4 under fast-spinning conditions. The polarization transfer dynamics are studied as a function of the spinning frequency and the frequency separation of the resonances. The results are consistent with a novel mechanism, in which four spins simultaneously exchange Zeeman magnetization with each other, in an energy-conserving process.

The ordering of fluoride ions on the anion sites in the oxyfluorides Ba 2 WO 3 F 4 , Ba 2 MoO 3 F 4 , CdWO 3 F 2 , NaMoO 3 F, and K 2 NbO 3 F has been studied with very fast magic angle spinning 19 F NMR. 19 F MAS NMR of Ba 2 WO 3 F 4 shows that the fluoride ions are disordered within the four equatorial anion positions on the W–O/F chains, but that the anion positions between the chains are fully occupied by fluorine. No difference in fluoride-ion ordering is observed between samples synthesized under a wide variety of conditions (e.g., hydrothermally at 3 kbar at 800°C, and at 227°C at 2 MoO 3 F 4 are almost completely ordered both between and on the W–O/F chains. Two-dimensional NMR is, however, used to demonstrate that a weak 19 F resonance corresponding to ≈0.35% of the total fluoride-ion content is not due to a BaF 2 impurity but that it results from a small amount of disorder in the tungsten chains. The fluoride ions order on one site in NaMoO 3 F and K 2 NbO 3 F, consistent with earlier studies. The 19 F and 19 F– 113 Cd REDOR NMR of CdWO 3 F 2 show that the fluoride ions are ordered on two anion sites, each equidistant from a cadmium ion, in contrast to the isostructural compound CuWO 3 F 2 where ordering on only one anion site has been proposed. A new model for the structure of CdWO 3 F 2 is proposed.

Aging results in progressive glomerular sclerosis and reductions in glomerular filtration rate (GFR). Oxidative stress may be an important mechanism for the aging process, but to date the role of oxidative stress on renal aging has not been determined. The present study was performed to determine whether age-related alterations in renal hemodynamics and morphology were associated with oxidative stress and whether this could be attenuated by chronic administration of vitamin E. Rats, aged 13 mo, were given either control diet containing vitamin E 50 IU/kg ( n = 6) or a high-vitamin E diet (5,000 IU/kg; n = 6) for 9 mo. Another group of rats (3–4 mo old; n = 7) served as young controls. Aging was accompanied by a 60% reduction in GFR, a threefold increase in renal F2isoprostanes, newly discovered vasoconstrictive F2-like prostaglandins generated by free radical-mediated lipid peroxidation. Renal aging was also associated with an increase in oxidant-sensitive heme oxygenase, advanced glycosylation end products (AGEs), and the AGE receptor, RAGE. AGE-RAGE interaction has been shown to induce oxidative stress. With high-vitamin E diet, GFR was increased by 50%, F2isoprostanes were suppressed, and expression of heme oxygenase and RAGE was attenuated. There was also a tendency for glomerular sclerosis to be attenuated. These data demonstrate that age-related decline in renal function is accompanied by oxidative stress and that administration of antioxidants, such as vitamin E, could attenuate the decline in renal function.

Metal fluorides/oxides (MF(x)/M(x)O(y)) are promising electrodes for lithium-ion batteries that operate through conversion reactions. These reactions are associated with much higher energy densities than intercalation reactions. The fluorides/oxides also exhibit additional reversible capacity beyond their theoretical capacity through mechanisms that are still poorly understood, in part owing to the difficulty in characterizing structure at the nanoscale, particularly at buried interfaces. This study employs high-resolution multinuclear/multidimensional solid-state NMR techniques, with in situ synchrotron-based techniques, to study the prototype conversion material RuO2. The experiments, together with theoretical calculations, show that a major contribution to the extra capacity in this system is due to the generation of LiOH and its subsequent reversible reaction with Li to form Li2O and LiH. The research demonstrates a protocol for studying the structure and spatial proximities of nanostructures formed in this system, including the amorphous solid electrolyte interphase that grows on battery electrodes.

A change in the electronic spin state of the surfaces relevant to Li (de)intercalation of nanosized stoichiometric lithium cobalt oxide LiCo(III)O(2) from low-spin to intermediate and high spin is observed for the first time. These surfaces are the ones that are relevant for Li (de)intercalation. From density functional theory calculations with a Hubbard U correction, the surface energies of the layered lithium cobalt oxide can be significantly lowered as a consequence of the spin change. The crystal field splitting of Co d orbitals is modified at the surface due to missing Co-O bonds. The electronic spin transition also has a significant impact on Co(III)-Co(IV) redox potential, as revealed by the change in the lithium (de)intercalation voltage profile in a lithium half cell.

Pillaring layered titanates with robust polyoxometallic oligomers is a route to prepare microporous titanium oxide. In addition to using the organic intercalated compounds as precursors, the pillaring reaction on this layered metal oxide with a high charge density was facilitated by using layered titanate of low crystallinity and small particle size, which was achieved by hydrolyzing TiCl 4 in strong alkaline solution. The resultant compound had a formula close to that of layered trititanate, NaHTi 3 O 7 ·2H 2 O. Both aluminium Keggin ions, formulated as [Al 13 O 4 (OH) 24 (H 2 O) 12 ] 7+ , and hydroxyzirconium tetramer cations, formulated as [Zr 4 (OH) 8 (H 2 O) 16 ] 8+ , were introduced into the interlayers of this layered titanate. The layered structure was retained up to 600°C for the alumina-pillared derivative, but only to 500°C for the zirconia-pillared derivative. The pillared samples had BET surface areas ⩾ 150 m 2 /g and contained both micro- and mesopores. Many of the physicochemical properties of the compounds before and after pillaring were compared. Most of the characteristic properties of TiO 2 were retained on the pillared derivatives.

There is an ever-increasing need for advanced batteries for portable electronics, to power electric vehicles and to facilitate the distribution and storage of energy derived from renewable energy sources. The increasing demands on batteries and other electrochemical devices have spurred research into the development of new electrode materials that could lead to better performance and lower cost (increased capacity, stability and cycle life, and safety). These developments have, in turn, given rise to a vigorous search for the development of robust and reliable diagnostic tools to monitor and analyse battery performance, where possible, in situ. Yet, a proven, convenient and non-invasive technology, with an ability to image in three dimensions the chemical changes that occur inside a full battery as it cycles, has yet to emerge. Here we demonstrate techniques based on magnetic resonance imaging, which enable a completely non-invasive visualization and characterization of the changes that occur on battery electrodes and in the electrolyte. The current application focuses on lithium-metal batteries and the observation of electrode microstructure build-up as a result of charging. The methods developed here will be highly valuable in the quest for enhanced battery performance and in the evaluation of other electrochemical devices.

The purpose of this study was to investigate the effects and mechanisms of 17beta-estradiol pharmacological postconditioning on gastric epithelial cells hypoxia/reoxygenation injury by using an in vitro model of human gastric epithelial cells. The model of hypoxia/reoxygenation was established with human gastric epithelial cell line. The gastric epithelial cell viability was detected by 3-(4, 5-dimethylthazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assays. Gastric epithelial cellular apoptosis was determined by Hoechst 33258 fluorochrome staining and flow cytometric analysis. Contents of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were measured by Colorimetry analysis. The protein expression of Bcl-2 and Bax in different groups was determined by Western blot analyses and immunocytochemistry assay. 17beta-estradiol (10(-8), 10(-7) and 10(-6)mol/l) inhibited hypoxia/reoxygenation injury and 17beta-estradiol (10(-6)mol/l) obviously attenuated hypoxia/reoxygenation injury 3h hypoxia followed by 4h reoxygenation. 17beta-estradiol promoted gastric epithelial cell viability and inhibited the gastric epithelial cell apoptosis, and meanwhile, decreased the MDA content and increased SOD activity. The level of Bcl-2 protein was restored to the normal level by 17beta-estradiol pharmacological postconditioning. In contrast, the Bax protein level was markedly reduced by 17beta-estradiol pharmacological postconditioning. These effects of 17beta-estradiol were inhibited by pretreatment with fulvestrant. These data suggested that 17beta-estradiol seems involved in regulation of gastric hypoxia/reoxygenation injury and gastroprotection, and its protective effects were strongly related to estrogen receptor.

Background No published study has addressed the effect of genistein postconditioning on gastric ischemia–reperfusion (GI–R) injury in rats. Aim To examine whether capsaicin receptor-mediated genistein postconditioning protects against gastric ischemia–reperfusion injury via the PI3K/Akt signal pathway. Methods and Results Chloraldurat-anesthetized rats underwent occlusion of the celiac artery for 30 min, followed by 60 min of reperfusion. Based on this animal model of gastric ischemia–reperfusion injury, genistein at doses of 100, 500 or 1,000 lg/kg was administered via peripheral vein 5 min before reperfusion. The dose of 500 lg/kg was optimal for postconditioning, at which the severity of I–R-induced gastric injury significantly decreased. Immunohistochemistry also showed that gastric mucosal cell apoptosis decreased. Capsazepine (CPZ), a specific antagonist for the capsaicin receptor, was administered (1,000 lg/kg, i.v.) just before ischemia. Capsaicin (50 mg/kg, s.c.) once a day for 4 days reversed the protective effects of genistein. Reverse transcriptionpolymerase chain reaction (RT-PCR) and Western blotting showed increased calcitonin gene-related peptide (CGRP) expression in genistein group but not in capsazepine or capsaicin group. CGRP inhibitor CGRP8-37 also prevented the effects of genistein in decreasing gastric mucosal injury index. In addition, PI3K inhibitor LY294002 (1.5 mg/kg) reversed the protective effect of genistein. Compared with genistein group, Western blots also demonstrated decreased Akt phosphorylation in LY294002 group. Conclusion Our data suggest that capsaicin receptors mediated the protective effects of genistein postconditioning. CGRP secreted by activated capsaicin-sensitive neurons played an important role in the protective effects of genistein. PI3K/Akt pathway was also involved in the protective effects of genistein.

The discovery of the physical phenomenon of Nuclear Magnetic Resonance (NMR) in 1946 gave rise to the spectroscopic technique that has become a remarkably versatile research tool. One could oversimplify NMR spectros-copy by categorizing it into the two broad applications of structure eluci-dation of molecules (associated with chemistry and biology) and imaging (associated with medicine). But, this certainly does not do NMR spectros-copy justice in demonstrating its general acceptance and utilization across the sciences. This manuscript is not an effort to present an exhaustive, or even partial review of NMR spectroscopy applications, but rather to pro-vide a glimpse at the wide-ranging uses of NMR spectroscopy found within the confines of a single magnetic resonance research facility, the Stanford Magnetic Resonance Laboratory. Included here are summaries of projects involving protein structure determination, mapping of intermolecular inter-actions, exploring fundamental biological mechanisms, following compound cycling in the environmental, analysis of synthetic solid compounds, and microimaging of a model organism.