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Highlights • The pathogenesis of MRONJ is related to repression of osteoclast mediated bone remodeling. • rhBMP-2 can stimulate not only osteoblasts but also osteoclasts and induce new bone formation. • ACS has been proved to be a good carrier of rhBMP-2 with maximal efficacy. • Application of rhBMP-2/ACS can be a new approach to surgical treatment for MRONJ patients., Introduction The purpose of this study was to pursue, and to report the results of, mandibular reconstruction and rehabilitation of medication-related osteonecrosis of the jaw (MRONJ) patients having large critical-sized defects of the mandible using a combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) and absorbable collagen sponge (ACS) with surgical miniplate without any grafting materials. Case presentation Three (3) patients aged 67 and 86 (2 patients) presented due to discomfort on the mandible. They all had a medical history of bisphosphonate and steroids treatment orally or intravenously, and all had been diagnosed as MRONJ stage 3. Sequestrectomy and saucerization were performed, and then a surgical miniplate (Hansolmedical, Korea) was adapted and fixed on the sound portion of the mandible. rhBMP-2 was loaded onto an ACS at a dose of 1.5 mg/cc. Several rhBMP-2 (Cowellmedi, Korea)/ACS (Ateloplug, TRMkorea, Korea) were placed into the bony defect with a surgical miniplate. All 3 patients recovered without complications. They all exhibited radiographic evidence of bone formation by 3 months postoperatively in every case. Conclusions All 3 patients were treated successfully with rhBMP-2/ACS and miniplate without any complications. This protocol reported herein represents a new approach to the surgical treatment of maxillofacial bone defects and deficiencies, especially in MRONJ patients.

The high stability and strong coupling nature of gold nanoparticles (Au-NPs) than other metal counter parts have attracted the solar cell industry to pursue enhanced performances. Herein, we report on the improved performance of polymer bulk hetero-junction (BHJ) solar cells by the incorporation of large-size Au-NPs in the hole transport layer of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). To examine the reproducibility of the enhancement parameters, two different donor photoactive materials have been adapted and the role of larger-size (>70 nm, i.e. 71, 80, 87, 103 nm) Au-NPs in BHJ solar cells have been studied extensively. Significantly, when employing Au-NPs smaller than 80 nm, near-field coupling (localized surface plasmon resonance; LSPR) was prevalent, while the infusion of Au-NPs with sizes greater than 87 nm resulted in far-field scattering enhancement as the dominant effect, which was clearly determined using time resolved photo luminescence studies. The superior power conversion efficiency of 5.35% and 8.58% was achieved with PBDTTT-C: PC61BM and PTB7: PC71BM BHJs respectively, by employing 87 nm Au-NPs due to the balanced contribution of near- and far-field plasmonic effects, improved vertical coverage and better interfacial properties. This study illustrates that 87 nm Au-NPs is the maximum size to attain the improved efficiency, above which the rate of enhancement reduces dramatically.

Purpose: This study examined the incidence of oral mucosa pressure ulcers (PUs) in intensive care unit (ICU) patients and the relationship between biomechanical and physiological variables in onset of PUs. Methods: A prospective observational descriptive study design was used. We recruited patients over 18 years of age with endotracheal tube (ETT) insertion in three ICUs in a tertiary hospital in Korea. We analysed 113 patient-days of data. Patient assessments and medical record reviews were conducted to gather biomechanical and physiological data. Fisher's exact tests and χ2 test and Spearman's rank correlations were used to compare data. Results: The highest incidence of oral mucosa PUs occurred in lower oral mucosa (36.3%). There was a significant relationship between lower oral mucosa PU stage and bite-block or airway use (r = .20, p = .036), commercial ETT holder use (r = 0.19, p = .048), sedative use (r = −0.22, p = .022), and plasma protein (r = 0.20, p = .033). Upper oral mucosa PU stage was related to commercial ETT holder use (r = 0.19, p = .044), haemoglobin(r = 0.24, p = .011), haematocrit (r = 0.27, p = .004), and serum albumin (r = −0.24, p = .012). Stage was related to commercial ETT holder use in both sites (r = 0.28, p = .003), haematocrit (r = 0.19, p = .039), and serum albumin (r = −0.23, p = .015). Conclusion: Oral mucosa PUs developed more frequently and healed more quickly than general skin PUs. Taken together, these data indicate that biomechanical and haematological variables are risk factors associated with PU incidence should be considered in intensive care patients.

For highly efficient and stable perovskite solar cells (PSCs), small molecular hole transporting materials (HTMs) with high glass transition temperature, hydrophobicity, excellent film-formation and excellent hole mobility is highly desireable. However, developing a single molecule, which could meet all the above mention properties, is challenging. Herein, novel small molecules were design and synthesized, which show a suitable HOMO energy level and fulfill the above metioned properties simultaneously. For this purpose, we incorporate a hydrophobic trifluoropropoxy-terminal group to diphenylamine in SGT-405(3,6), a carbazole-based promising non-spiro-type small molecular HTM with excellent performance and low-cost, leading to two new HTMs (SGT-405s(C2,CF3) and SGT-405d(C2,CF3)). Among them SGT-405s(C2,CF3) showed an excellent hole mobility of 3.32 × 10–4 cm2 V−1 s−1, a remarkable high Tg of 183 ℃ and increased water contact angle of 87° compared to that of spiro OMeTAD (77.7°). Due to these superior properties, compared to those of spiro-OMeTAD, PSCs based on SGT-405s(C2,CF3) showed a remarkable power conversion efficiency (PCE) of 20.14%, which is higher than that of spiro-OMeTAD (18.97%), together with enhanced long-term and thermal stability. Our work revealed for the first time that trifluoropropoxy is a potential terminal group and an effective strategy for the design of new HTMs possessing superior properties in terms of glass transition temperature, hydrophobicity and film formation, for realizing efficient PSCs with enhanced moisture and thermal stability, simultaneously.

o-Carborane was used to alter the electronic states of π-conjugated organic aryls, and demonstrated as an effective electron control unit, to tune HOMO and LUMO energies for the electron transfer. Two different types of bis-aryl compounds were selected: one with di-phenyls and its fused fluorenyl, and another with two isomers of naphthyls, α- and β-forms. Among the series of aryl compounds, the second type of naphthyls were more susceptible to electronic alteration and α-isomer of naphthyl showed the most perturbed electronic state. The ground state structures confirmed by crystallographic measurements provide a close correlation of structure and electronic property between photo-responsive aryl groups and o-carborane. In addition to the distance effect, within similar proximity of the aryl functional groups, namely naphthyl case, the steric factor controlled the altered electronic state. HOMO and LUMO energies were estimated and confirmed by cyclic voltammograms and DFT calculations, respectively, and established the authenticity of the electronic alteration. Excited states were calculated by the TD-DFT correlations with the corresponding absorption spectra to illustrate the electronic perturbation in a systematic fashion suggesting that excited states were lowered in regard to the electronic perturbation. Therefore, within bis-aryls-o-carborane series, the following decreasing energy order is observed; α-Np, β-Np, Flu, diPh, and Ph. The final verification of the lowered energy was made according to the electron transfer efficiency between the well-studied iridium based photosensitizer, Ir(ppy)3 and two typical bis-aryls-o-carboranes, α-Np and Ph. The electron transfer efficiency of α-Np is 10 times greater than that of Ph (1.231 × 107 M−1s−1 for α-Np and 9.275 × 105 M−1s−1 for Ph).

Two new D-π-A-structured dyes (SGT-160 and SGT-161) with the extension of π-conjugation in the acceptor unit have been designed and synthesized to modulate LUMO energy levels and to investigate the photophysical and electrochemical properties as well as cell performances. Based on a reference dye of SGT-130 as a platform of donor-π-bridge-BTD-phenyl-acceptor sensitizers, ethynylphenylene (T-Ph) and 2-ethynylthiophene (T-Th) moieties as an auxiliary π-spacer were introduced to replace the traditional phenylene (Ph) moiety for SGT-160 and SGT-161, respectively. It was found that the insertion of an additional ethynyl moiety into the BTD-Ph acceptor unit significantly enhanced the light-harvesting capability by extending the absorption bands and intensifying the molar absorptivity. Moreover, the π-extension in the acceptor part was beneficial for stabilizing the LUMO energy levels. The density functional theory (DFT) calculations and the partial density of states (PDOS) suggest that the variation of acceptor units affects the electronic transition between the major orbitals of the dyes. As a result, dye-sensitized solar cells (DSSCs) based on SGT-160 with a chenodeoxycholic acid (CDCA) co-adsorbent exhibited high power conversion efficiencies (PCEs) of 10.28%, while DSSCs based on SGT-161 and SGT-130 showed moderate PCEs of 8.05% and 10.06%, respectively.

The oxytocin receptor (OXTR) is a potential candidate in the pathophysiology of obsessive-compulsive disorder (OCD). The present study investigated the association between common single-nucleotide polymorphism (SNPs) of the OXTR gene and the affected status of OCD or distinct clinical subtypes of OCD including the age at onset and symptom dimensions. Ten SNPs of OXTR were examined in 615 patients with OCD and 581 healthy controls. Single-marker and haplotype-based association analyses were conducted. While OXTR variants were not associated with the affected status of OCD or its clinical symptom dimensions, rs2268493 (p=0.00185) and rs13316193 (p=0.00461) of the OXTR gene were associated with the age at onset in patients with OCD. In addition, in haplotype-based association analyses, there was a significant association between the OXTR gene and the onset age in patients with OCD. In particular, the G-C-G haplotype of rs2268493-rs2254298-rs11316193 and the T-G-A haplotype of rs237887-rs2268490-rs4686301 were positively associated with late-onset OCD. Our results suggest that common variants of OXTR may exert a modulating effect on the onset age in OCD pathophysiology. The potential involvement of the oxytocin system in the development and expression of OCD warrants further longitudinal research.

The hole transporting materials (HTMs) have been extensively studied since the HTMs play a critical role in promoting charge extraction/transport and reducing charge recombination between the perovskite layer and the top metal electrode, thus improving the device power conversion efficiency (PCE). In this study, novel polymeric HTMs with pentacyclic pyrroloindacenodithiophene (NIDT) as an electron-rich unit, and electron-deficient benzotriazole (BTA) as an acceptor, labelled as SGT-512 and SGT-513, were designed and synthesized. To regulate the electron withdrawing ability of the acceptor part, two thiophene units were introduced to the BTA moiety as an acceptor, yielding SGT-513 with a slightly raised HOMO energy level. The alkyl side-chain was introduced to the fused BTA unit to improve the solubility and regulate the morphology and stacking behavior of HTM. Meanwhile, for the donor part, the replacement of the bridging heteroatom in indacenodithiophene with the more electron donating nitrogen atom, helped to promote molecular orbital hybridization leading to a narrower bandgap polymer. The combination of the features of the NIDT donor and BTA acceptor enabled the production of the D-A type polymeric HTM SGT-512 with a high intrinsic hole mobility of 3.8 × 10−4 cm2V−1s−1, a suitable HOMO energy level (−5.25 eV) corresponding to the valence band of the perovskite layer, and excellent film-formation ability. Therefore, the PrSCs based on dopant-free SGT-512 showed a high PCE of 15.57%, which is much higher than that of the control device based on dopant free-P3HT, with a PCE of 13.52%.

The risk of Alzheimer's disease (AD) is higher in patients with type 2 diabetes mellitus (T2DM). Previous studies in high-fat diet-induced AD animal models have shown that brain insulin resistance in these animals leads to the accumulation of amyloid beta (Aβ) and the reduction in GSK-3β phosphorylation, which promotes tau phosphorylation to cause AD. No therapeutic treatments that target AD in T2DM patients have yet been discovered. Agmatine, a primary amine derived from l-arginine, has exhibited anti-diabetic effects in diabetic animals. The aim of this study was to investigate the ability of agmatine to treat AD induced by brain insulin resistance. ICR mice were fed a 60% high-fat diet for 12 weeks and received one injection of streptozotocin (100 mg/kg/ip) 4 weeks into the diet. After the 12-week diet, the mice were treated with agmatine (100 mg/kg/ip) for 2 weeks. Behaviour tests were conducted prior to sacrifice. Brain expression levels of the insulin signal molecules p-IRS-1, p-Akt, and p-GSK-3β and the accumulation of Aβ and p-tau were evaluated. Agmatine administration rescued the reduction in insulin signalling, which in turn reduced the accumulation of Aβ and p-tau in the brain. Furthermore, agmatine treatment also reduced cognitive decline. Agmatine attenuated the occurrence of AD in T2DM mice via the activation of the blunted insulin signal.

X-ray free electron lasers (XFELs) require electron beams with a peak current of several kA and a transverse emittance below 1 mm mrad. The uncorrelated energy spread of the beam should be as small as 0.01% of the beam energy. A photoinjector generates an electron beam satisfying the requirements, however the uncorrelated energy spread of the beam is too small, about one keV. A beam with such a low uncorrelated energy spread may suffer from the longitudinal microbunching instability when the beam is accelerated and compressed through a linear accelerator. A laser heater system in the injector minimizes the microbunching instability growth by controlling the uncorrelated energy spread of the beam. In this paper, we introduce the PAL-XFEL laser heater system and the commissioning result. The laser heating effects depending on the undulator gap, infrared laser pulse energy and laser beam size are studied. Experimental studies on the laser heating depending on the relative spatial position between the infrared laser and electron beam are discussed in detail.

The rate of hippocampal neurogenesis declines with aging. This is partly explained by decreased neural responsiveness to various cues stimulating metabolism. AMP-activated protein kinase (AMPK), a pivotal enzyme regulating energy homeostasis in response to metabolic demands, showed the diminished sensitivity in peripheral tissues during aging. AMPK is also known to be involved in neurogenesis. We aimed to see whether AMPK reactivity is also blunted in the aged hippocampus, and thus is associated with aging-related change in neurogenesis. Following subchronic (7days) intraperitoneal and acute intracerebroventricular (i.c.v.) administration of either 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR; AMPK activator) or saline (sham) to young (16-week-old) and old (72-week-old) mice, we measured changes in AMPK activity, brain-derived neurotrophic factor (BDNF) expression or neurogenesis in the hippocampus. AICAR-induced changes in AMPK activity were observed in the hippocampus of young mice after acute i.c.v. injection. However, neither subchronic nor acute treatment induced significant changes in AMPK activity in old mice. Intriguingly, directions of AICAR-induced changes in AMPK activity were opposite between the hippocampus (decrease) and skeletal muscle (increase). ATP levels were inversely correlated with hippocampal AMPK activity, suggesting that the higher energy levels achieved by AICAR treatment might deactivate neuronal AMPK in young mice. The blunted response of AMPK to AICAR in old age was also indicated by the observations that the levels of neurogenesis and BDNF expression were significantly changed only in young mice upon AICAR treatment. Our findings suggest that the blunted response of neuronal AMPK in old age might be responsible for aging-associated decline in neurogenesis. Therefore, in addition to activation of AMPK, recovering its sensitivity may be necessary to enhance hippocampal neurogenesis in old age.

The conventional [(CH3NH3I (MAI)):PbI2:PbCl2 = 3 : 0: 1 [abbreviated as (3:0:1)]] precursor solution is known to result in CH3NH3PbI3–xClx films with large grain sizes when processed in an inert atmosphere, but it gives non-uniform perovskite films containing lots of voids and cracks when processed in ambient air. Furthermore, a dramatically longer annealing time (usually 100 min) is required for these films (3:0:1) due to the slow formation of the MAPbI3 phase via MACl loss, which is not conducive to perovskite film formation under ambient conditions due to perovskite degradation upon long exposure to moisture. Pure MAPbI3 films can be formed very rapidly from (1:1:0) (MAI:PbI2:PbCl2 = 1 : 1: 0) solution within a short annealing time, but they show small grain sizes and poor film quality. This work demonstrated that a fractional substitution of PbI2 with PbCl2 in the ([MAI]:[PbI2] = 1 : 1) precursor solution has a significant influence on film morphology and quality in terms of crystallization rate, grain size, crystallinity, and trap density of the formed perovskite film. Perovskite films can be formed with 5-min annealing at 100 °C from the precursor (MAI: PbI2:PbCl2 = 1: 0.8 : 0.2) processed in ambient air (humidity, 20% RH), exhibiting more uniform, increased grain size and higher film quality with reduced trap densities compared to film (1:1:0), thus leading to significantly improved power conversion efficiency (PCE), from 16.7% for perovskite solar cells (PrSCs) based on film (1:1:0) to 20.04% for the cell based on film (1:0.8:0.2). Further, the effects of R (R = [MAI]/[PbI2+PbCl2]) on morphology, hole mobility, carrier lifetime and efficiency of PrSCs were systematically and thoroughly investigated. This study found that MAPbI3–xClx at R = 1 can enable the highest hole mobility and longest carrier lifetime, thus giving the best performance at R = 1.

The purpose of the present study is to investigate the relationship between dopaminergic neuron destruction and 5-HT system changes in a hemiparkinsonian rat model. We performed PET imaging studies with trans -[ 18 F]Mefway in a hemiparkinsonian model of unilateral 6-hydroxydopamine (6-OHDA) rats. Region-of-interests (ROIs) were drawn in the hippocampus (HP) and cerebellum (CB). HP uptake, the ratios of specific binding to non-specific binding in the HP, and non-displaceable binding potential (BP ND ) in the HP were compared between 6-OHDA and control rats. As a result, unilateral 6-OHDA-lesioned rats exhibited significant bilateral reduction of HP uptake and trans -[ 18 F]Mefway BP ND compared to the intact control group. Therefore, the results demonstrate that destruction of the dopaminergic system causes the reduction of the serotonergic system.

An individual's behavior is generally based on genetic blueprint and previous experiences. A coping strategy, affected by personal interpretation of past events, can be determined by behavioral controllability of stress. In this study, we examined the relationship between the hippocampal mGluR5 expression and coping strategies to stress. Rats were exposed to stress via inescapable and unpredictable footshocks on PNDs 14 and 90. Coping strategies to stress were also measured. Hippocampal mGluR5 was found to be linked to the behavioral coping strategy, as it increased in rats that showed helplessness behavior (HL (+) group) and decreased in those that did not (HL (-) group). Also, the HL (+) group showed a lack of adaptation in a novel environment but the HL (-) group did not. The results suggest that mGluR5 has a pivotal role in the controllability-based coping strategy. Hippocampal mGluR5 could be a target molecule in the manipulation of neuropsychiatric conditions for which maladaptation is a part of behavioral consequences.

Astrocytic gap junctions have been implicated in the regulation of cell viability. High amounts of extracellular zinc, which is released during ischemia, seizure, and brain trauma, can be cytotoxic to astrocytes. We tested whether gap junction coupling between astrocytes plays an important role in modulating zinc toxicity in hippocampal astrocytes. Zinc induces cell death in a dose-dependent manner in primary cultured hippocampal astrocytes. Two gap junction inhibitors, 18β-glycyrrhetinic acid and arachidonic acid, had no effect on zinc-induced cell death in low-confluence culture, where physical separation prevents gap junctions from forming. However, these inhibitors can potentiate zinc toxicity in high-confluence astrocyte cultures. Zinc toxicity was substantially suppressed upon connexin 43 overexpression, whereas knockdown caused a significant enhancement of the toxicity in high-confluence cultures. These data suggest that gap junctions in hippocampal astrocytes provide a protective role against zinc toxicity.

Dysregulation of Wnt signaling has been implicated in tumorigenesis. The role of Transducin β-like proteins TBL1-TBLR1 in the promotion of Wnt/β-catenin-mediated oncogenesis has recently been emphasized; however, the molecular basis of activation of Wnt signaling by the corepressor TBL1-TBLR1 is incompletely understood. Here, we show that both TBL1 and TBLR1 are SUMOylated in a Wnt signaling-dependent manner, and that this modification is selectively reversed by SUMO-specific protease I (SENP1). SUMOylation dismissed TBL1-TBLR1 from the nuclear hormone receptor corepressor (NCoR) complex, increased recruitment of the TBL1-TBLR1-β-catenin complex to the promoter of Wnt target genes, and consequently led to activation of Wnt signaling. Conversely, SENP1 decreased formation of the TBL1-TBLR1-β-catenin complex, leading to inhibition of β-catenin-mediated transcription. Importantly, inhibition of SUMOylation significantly decreased the tumorigenicity of SW480 colon cancer cells. Thus, our data reveal a mechanism for activation of Wnt signaling via the SUMOylation-dependent disassembly of the corepressor complex.

This study investigated the effects of dietary supplementation with the prebiotics fructo-oligosaccharide (FOS) and mannan-oligosaccharide (MOS) on the performance, small intestinal microflora, and immune response of broilers. Two hundred forty 1-d-old Ross broiler chickens were randomly assigned to 6 dietary treatment groups: control, avilamycin (6 mg/kg), 0.25% FOS, 0.5% FOS, 0.025% MOS, and 0.05% MOS. Each treatment was fed to 4 replicates of 10 birds per diet for 4 wk. Except for the 0.5% FOS group, the overall BW gains of birds treated with avilamycin and prebiotics were significantly(P < 0.05) higher than those of the control group. No significant differences were found between the control and supplemented groups in overall feed intake, feed conversion, and mortality. The 0.05% MOS group was significantly (P < 0.05) lower than the control and 0.5% FOS groups in heterophil:lymphocyte ratio and basophil level. Concentrations of plasma IgA and IgG were not significantly different among the treatment groups. Quantitative real-time PCR indicated that supplementation of the diet with avilamycin or prebiotics caused significant (P < 0.05) changes in the small intestinal microbial community, as determined in samples obtained at the ileocecal junction. The populations of Clostridium perfringens and Escherichia coli decreased with 0.25% FOS, 0.05% MOS, or avilamycin, and lactobacilli increased in the 0.25% FOS and 0.25% MOS treatment groups. Total bacteria increased in the 0.25% FOS and 0.05% MOS treatments and decreased in the avilamycin treatment. Feeding 0.25% FOS and 0.05% MOS resulted in an increase in lactobacillus community diversity in the ileum. Our results showed that 0.25% FOS and 0.05% MOS were comparable with avilamycin in improving productivity in broilers raised in wire floor cages up to 28 d of age. Plasma immunoglobulins were not affected by prebiotics, but the heterophil:lymphocyte ratio, basophil level, and microbial population in the ileum were significantly affected.

Nowadays, attempts to use nanoparticles for medical applications are on the rise. However, the effect of nanoparticles in the body has not been clarified. In this study, we aimed to examine the pharmacokinetics of magnetized nanoparticles. FITC conjugated SA-MnMEIO nanoparticles were prepared for the purpose of tracing. Nanoparticles (15 nm diameter) were injected into the tail vein of BALB/c mice at a dose of 20 mg (Mn+Fe)/kg. A mouse was housed in a metabolic cage and sacrificed serially up to 14 days for the sampling of blood and tissues from various organs (i.e., heart, kidney, liver, and spleen). The concentration of nanoparticles was measured by detecting FITC using spectrofluorophotometer. Nanoparticles showed a half-life of 8.20 h. The fluorescence intensities of nanoparticles in tissues showed different time-dependent patterns among different organs. In the heart and the liver, the fluorescence intensities increased up to 2 weeks of observation, while those in the kidney and the spleen decreased. The results indicate that nanoparticles have unique pharmacokinetic characteristics and suggest that pharmacokinetic study is essential for the development of new nanoparticles for medical use.

Lithospermic acid B (LAB), an active component isolated from Salvia miltiorrhizae, has been reported to have renoprotective effects in type 1 diabetic animal models. In the present study we investigated the effects of LAB on the prevention of diabetic nephropathy in type 2 diabetic Otsuka Long-Evans-Tokushima Fatty (OLETF) rats. LAB (20 mg/kg) was given orally once daily to 10-week-old male OLETF rats for 28 weeks. Treatment of OLETF rats with LAB had little effects on body weight and blood glucose levels. Treatment with LAB resulted in significant reduction in blood pressure. LAB markedly attenuated albuminuria and significantly lowered levels of lipid peroxidation, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-β (TGF-β1) expression in renal tissues of OLETF rats. In addition, LAB inhibited the progression of glomerular hypertrophy, mesangial expansion, and expansion of the extracellular matrix in the renal cortex. Collectively, these results suggest that LAB has beneficial effects on the diabetic nephropathy in OLETF rats by decreasing blood pressure, oxidative stress, and MCP-1 expression. Our results suggest that LAB might be a new therapeutic agent for the prevention of nephropathy in type 2 diabetes.

Dynamics of the excited state intramolecular proton transfer of a polyquinoline in solution and polymer film has been studied by time-resolved fluorescence. The proton transfer occurs rapidly in both solution and polymer film at 130 and 55 fs, respectively. In solution, however, the dynamics is quite dispersive, as the 130 fs component comprises ∼30% of the fluorescence decay and the remainder at slower rates. The dynamics is homogeneous in the polymer film. The dynamics are consistent with the stationary fluorescence spectra reported previously. Conformational heterogeneity in the dihedral angle is invoked to account for the dispersive dynamics.

A critical role of oxidative stress has been implicated in ischemic brain damage. Mild ischemic pretreatment and/or synthesis of heat shock proteins (HSPs) has been suggested to protect against oxidative brain damage. However, experimental support of this suggestion have proven to be difficult partly because sensitive indices to assess oxidative consequences of ischemic brain damage were few. In this study, we have attempted to establish biochemical assay systems to quantitate oxidative brain damage following ischemia. We produced experimental brain ischemia in the Mongolian gerbil (Meriones unguiculatus) and examined the hippocampus for ischemic brain damage. The results obtained from ischemic gerbil hippocampus demonstrated that oxidative brain damage can be quantitated by determining glutathione oxidation ratio together with the accumulation of the oxidative DNA damage product, 8-hydroxy-2'-deoxyguanosine (8 ohdG). Our results also demonstrated a role for mild ischemic pretreatment and synthesis of HSPs against oxidative brain damage. We showed that mild 2-min ischemic pretreatment reduced the degree of both glutathione oxidation ratio and 8 ohdG accumulation in gerbil hippocampus subsequent to 10 min ischemic challenge. We also showed that the accumulation of HSP70 was closely associated with the reduction of oxidative brain damage. To our knowledge, this is the first report to investigate glutathione redox states and oxidative DNA damage levels to evaluate a protective role of mild ischemic pretreatment and HSP synthesis following brain ischemia. Our data validate the previous suggestions and provide new additional data that argue for the protective role of mild ischemic pretreatment and HSP70 synthesis against oxidative brain damage.