Locking water molecules via ternary O-H⋯O intramolecular hydrogen bonds in perhydroxylated closo-dodecaborate.

A multitude of applications related to perhydroxylated closo-dodecaborate B12(OH)122- in the condensed phase are inseparable from the fundamental mechanisms underlying the high water orientation selectivity based on the base B12(OH)122-. Herein, we directly compare the structural evolution of water clusters, ranging from monomer to hexamer, oriented by functional groups in the bases B12H122-, B12H11OH2- and B12(OH)122- using multiple theoretical methods. A significant revelation is made regarding B12(OH)122-: each additional water molecule is locked into the intramolecular hydrogen bond B-O-H ternary ring in an embedded form. This new pattern of water cluster growth suggests that B-(H-O)⋯H-O interactions prevail over the competition from water-hydrogen bonds (O⋯H-O), distinguishing it from the behavior observed in B12H122- and B12H11OH2- bases, in which competition arises from a mixed competing model involving dihydrogen bonds (B-H⋯H-O), conventional hydrogen bonds (B-(H-O)⋯H-O) and water hydrogen bonds (O⋯H-O). Through aqueous solvation and ab initio molecular dynamics analysis, we further demonstrate the largest water clusters in the first hydrated shell with exceptional thermodynamic stability around B12(OH)122-. These findings provide a solid scientific foundation for the design of boron cluster chemistry incorporating hydroxyl-group-modified borate salts with potential implications for various applications.

Near-Unity Triplet Generation Promoted via Spiro-Conjugation.

An intersystem crossing (ISC) rate constant of 1.0×1011  s-1 was previously registered with a spiro-bis-benzophenone scaffold. Triplet generation efficiency could be further enhanced by stabilizing the spiro-charge-transfer (CT) state and rationally designing spiro-compounds (SCTs) that consist of electron-rich diphenyl ether as the spiro-CT donor and electron-deficient dinaphthyl ketone as the spiro-CT acceptor. Through fine-tuning of the energy level between the CT and high energy triplet states, near-unity triplet generation quantum yield was achieved and the underlying ISC mechanism is revealed by using ultrafast spectroscopy and quantum chemical calculations. Potential triplet sensitizing application was demonstrated in SCTs. Our findings suggest that a spiro-bichromophoric molecular system with an enhanced spiro-charge transfer warrants efficient triplet generation and is a powerful strategy of heavy-atom-free triplet sensitizers with predictable ISC properties.

Orthogonal Self-Assembly of a Two-Step Fluorescence-Resonance Energy Transfer System with Improved Photosensitization Efficiency and Photooxidation Activity.

During the past few decades, fabrication of multistep fluorescence-resonance energy transfer (FRET) systems has become one of the most attractive topics within supramolecular chemistry, chemical biology, and materials science. However, it is challenging to efficiently prepare multistep FRET systems with precise control of the distances between locations and the numbers of fluorophores. Herein we present the successful fabrication of a two-step FRET system bearing specific numbers of anthracene, coumarin, and BODIPY moieties at precise distances and locations through an efficient and controllable orthogonal self-assembly approach based on metal-ligand coordination and host-guest interactions. Notably, the photosensitization efficiency and photooxidation activity of the two-step FRET system gradually increased with the number of energy transfer steps. For example, the two-step FRET system exhibited 1.5-fold higher 1O2 generation efficiency and 1.2-fold higher photooxidation activity than that of its corresponding one-step FRET system. This research not only provides the first successful example of the efficient preparation of multistep FRET systems through orthogonal self-assembly involving coordination and host-guest interactions but also pushes multistep FRET systems toward the application of photosensitized oxidation of a sulfur mustard simulant.

Gaseous cyclodextrin-closo-dodecaborate complexes χCD·B12X122- (χ = α, ß, and γ; X = F, Cl, Br, and I): electronic structures and intramolecular interactions.

A fundamental understanding of cyclodextrin-closo-dodecaborate inclusion complexes is of great interest in supramolecular chemistry. Herein, we report a systematic investigation on the electronic structures and intramolecular interactions of perhalogenated closo-dodecaborate dianions B12X122- (X = F, Cl, Br and I) binding to α-, ß-, and γ-cyclodextrins (CDs) in the gas phase using combined negative ion photoelectron spectroscopy (NIPES) and density functional theory (DFT) calculations. The vertical detachment energy (VDE) of each complex and electronic stabilization of each dianion due to the CD binding (ΔVDE, relative to the corresponding isolated B12X122-) are determined from the experiments along α-, ß- and γ-CD in the form of VDE (ΔVDE): 4.00 (2.10), 4.33 (2.43), and 4.30 (2.40) eV in X = F; 4.09 (1.14), 4.64 (1.69), and 4.69 (1.74) eV in X = Cl; 4.11 (0.91), 4.58 (1.38), and 4.70 (1.50) eV in X = Br; and 3.54 (0.74), 3.88 (1.08), and 4.05 (1.25) eV in X = I, respectively. All complexes have significantly higher VDEs than the corresponding isolated dodecaborate dianions with ΔVDE spanning from 0.74 eV at (α, I) to 2.43 eV at (ß, F), sensitive to both host CD size and guest substituent X. DFT-optimized complex structures indicate that all B12X122- prefer binding to the wide openings of CDs with the insertion depth and binding motif strongly dependent on the CD size and halogen X. Dodecaborate anions with heavy halogens, i.e., X = Cl, Br, and I, are found outside of α-CD, while B12F122- is completely wrapped by γ-CD. Partial embedment of B12X122- into CDs is observed for the other complexes via multipronged B-XH-O/C interlocking patterns. The simulated spectra based on the density of states agree well with those of the experiments and the calculated VDEs well reproduce the experimental trends. Molecular orbital analyses suggest that the spectral features at low binding energies originated from electrons detached from the dodecaborate dianion, while those at higher binding energies are derived from electron detachment from CDs. Energy decomposition analyses reveal that the electrostatic interaction plays a dominating role in contributing to the host-guest interactions for the X = F series partially due to the formation of a O/C-HX-B hydrogen bonding network, and the dispersion forces gradually become important with the increase of halogen size.

Photoelectron spectroscopy and computational investigations of the electronic structures and noncovalent interactions of cyclodextrin-closo-dodecaborate anion complexes χ-CD·B12X122- (χ = α, ß, γ; X = H, F).

We report a joint negative ion photoelectron spectroscopy (NIPES) and computational study on the electronic structures and noncovalent interactions of a series of cyclodextrin-closo-dodecaborate dianion complexes, χ-CD·B12X122- (χ = α, ß, γ; X = H, F). The measured vertical/adiabatic detachment energies (VDEs/ADEs) are 1.15/0.93, 3.55/3.20, 3.90/3.60, and 3.85/3.60 eV for B12H122- and its α-, ß-, γ-CD complexes, respectively; while the corresponding values are 1.90/1.70, 4.00/3.60, 4.33/3.95, and 4.30/3.85 eV for the X = F case. These results show that the inclusion of B12X122- into the CD cavities greatly increases the electronic stability of the dianions. The effect of electronic stabilization for ß-CD is roughly the same as for γ-CD, both being considerably stronger than that for α-CD. Density functional theory (DFT) based geometry optimization reveals that B12X122- are inserted into CDs increasingly deeper from α-CD to γ-CD. The calculated VDEs and ADEs agree with the experiments well, particularly, reproducing the electron binding energy (EBE) trends. The molecular orbital analyses indicate that the most loosely bound photodetached electrons originate from the guest B12X122- moieties. In addition to a shift of all signals to a larger EBE, significant changes in the signal patterns are observed. At low EBE, this is due to the splitting of highly degenerate B12X122- orbitals, while at high EBE, photodetachment from CD oxygens contributes to the new bands. The guest B12X122- and host CD noncovalent, size-specific interaction based on the independent gradient model (IGM) and energy decomposition analysis (EDA) is dominated by electrostatic interactions. The analysis further unravels unambiguously the existence of dihydrogen bonding and how it affects the total energy that stabilizes the host-guest complexes of CDs·B12H122- compared to the general hydrogen bonding interaction in CDs·B12F122-. This work clearly exhibits strong influences on the electronic structures of dodecaborates upon clustering with CDs, with both size (α-, ß-, and γ-) and molecular (X = H or F) specificities, thus providing critical molecular-level information on the cyclodextrin-closo-dodecaborate interactions of interest to medical applications, e.g., boron neutron capture therapy.

Electronic structures and binding motifs of sodium polysulfide clusters NaSn - (n = 5-9): A joint negative ion photoelectron spectroscopy and computational investigation.

We report a joint experimental and computational study on the electronic and geometric structures of a series of NaSn - (n = 5-9) clusters. Cryogenic, size-selective, negative ion photoelectron spectroscopy was employed to obtain their photoelectron spectra, in which distinctive spectral features with electron binding energy (EBE) up to 6.4 eV are unraveled. The EBE of the first peak in each spectrum for NaSn - (n = 5-9), assigned to the transition from the ground state of the anion to the ground state of each neutral radical, was observed to increase with cluster size. The vertical detachment energies (VDEs), measured from the first peak maximum, are 3.43 ± 0.02, 3.57 ± 0.02, 3.82 ± 0.03, 3.86 ± 0.02, and 4.00 ± 0.02 eV, and the adiabatic detachment energies (ADEs), determined from the onset of the first peak, are 3.27 ± 0.05, 3.44 ± 0.05, 3.65 ± 0.05, 3.75 ± 0.05, and 3.93 ± 0.05 eV, for n = 5-9, respectively. A number of low-lying isomers of the anions were screened and identified with density functional theory calculations, showing a structural preference of a chainlike polysulfide moiety electrostatically interacting with a sodium cation for all of the clusters. The CCSD(T)/aug-cc-pVTZ calculated VDEs and ADEs are in excellent agreement with the experimental results, confirming the identified isomers. Further analyses based on excited-state transitions, molecular orbitals, and natural population charges were performed, to assign and reveal the nature of all observed spectral bands. These computational results suggest that the electron detachment process and observed excitations are mainly derived from the polysulfide chain within each NaSn - cluster. This work provides a fundamental understanding of the intrinsic molecular properties of sodium polysulfide systems, which widely exist in life science and sodium-sulfur cells.

Theoretical exploitation of acceptors based on benzobis(thiadiazole) and derivatives for organic NIR-II fluorophores.

Small-molecule dyes with fluorescence emission in the second near-infrared (NIR-II) region (1000-1700 nm) have attracted considerable attention in the biomedical and bioimaging fields due to their greater imaging depths, better spatial resolution, and higher signal-to-background ratios. However, currently reported organic NIR-II fluorophores are still limited and there is great demand to develop other novel NIR-II fluorophores besides benzobisthiadiazole (BBT)-based fluorophores. More importantly, there is a lack of an appropriate level of theory capable of providing both efficient and accurate predictions of the electronic structures of organic NIR-II fluorophores. In this work, successful application of time-dependent density functional theory (TDDFT) using optimally-tuned range-separated functionals for calculations of both absorption and fluorescence spectral properties has been demonstrated, compared with the available experimental data. A series of thiadiazole-based acceptors (A) and derivatives based on the D-A-D skeleton are designed coupled with the triphenylamine donor (D). The structure-property relationships for these fluorophores are thus revealed by analyzing their ground (S0) and excited (S1) state geometries, frontier molecular orbitals (HOMO and LUMO), HOMO-LUMO energy gaps, oscillator strengths, hole-electron distributions and fluorescence wavelengths. It is suggested that the existence of a hypervalent structure leading to a much lower LUMO level and accompanying significant hole-electron separation plays a key role in the red-shift of fluorescence emission in the NIR-II region. In addition, the substitution of BBT oligomers and analogues as acceptor cores is an efficient way to achieve both red-shifted fluorescence wavelengths and enhanced oscillator strengths. The present work provides a reliable and efficient theoretical tool for predicting the related electronic and spectral properties of organic fluorophores and future screening out of potential candidates for excellent NIR-II molecular fluorophores.

Preoperative Timing of Intravitreal Bevacizumab Injection for Proliferative Diabetic Retinopathy Patients.

OBJECTIVE: To evaluate the changes in aqueous concentrations of inflammatory cytokines and fibrosis-related factors, and to detect the expression of vascular endothelial growth factor (VEGF) and proliferating cells in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy (PDR) after injection of intravitreal bevacizumab (IVB). METHODS: Forty-two eyes of 42 patients with PDR, including 28 eyes that received IVB (1.25 mg) 2, 5, and 14 days before pars plana vitrectomy (PPV), and 14 eyes without IVB, were enrolled, in addition to 10 eyes of 10 patients with nondiabetic ocular diseases. Aqueous concentrations of inflammatory cytokines and fibrosis-related factors were analyzed by a multiplex bead assay. Fluorescence immunostaining was performed to examine the expression of VEGF and proliferating cells in the excised epiretinal membranes. RESULTS: PDR eyes without IVB had the highest vitreous VEGF levels, and the level was statistically significant compared with that of PDR eyes that received IVB 2 days before surgery, PDR eyes that received IVB 5 days before surgery, and nondiabetic eyes (p = 0.011, p = 0.012, and p < 0.001, respectively). The expression of fibroblastic cells and connective tissue growth factor increased in epiretinal FVMs of the IVB group 21 days after treatment. CONCLUSIONS: IVB injection may lead to a decrease in the intraocular concentrations of VEGF after 2-5 days and induce the formation of proliferation after 21 days, which suggests that PPV in PDR patients should take place within 1 week of the administration of preoperative IVB.

Vascular endothelial growth factor plasma levels before and after treatment of retinopathy of prematurity with ranibizumab.

PURPOSE: To evaluate vascular endothelial growth factor (VEGF) plasma levels before and after intravitreal injection of ranibizumab in patients with retinopathy of prematurity (ROP). METHODS: Case series study. Eleven infants with type 1 pre-threshold ROP were treated with intravitreal ranibizumab 0.5 mg. Blood samples were collected before intravitreal injection of ranibizumab and 1 day, 1 week, 2 weeks, and 4 weeks after injection. Concentration of plasma VEGF was measured by enzyme-linked immunosorbent assays (ELISA). RESULTS: The mean ± standard deviation of plasma VEGF concentration of the available samples before and 1 day, 1 week, 2 weeks, and 4 weeks after a total of 0.5 mg ranibizumab injection were 46.07 ± 9.40 pg/ml (n = 11), 10.59 ± 7.32 pg/ml (n = 5), 45.76 ± 6.75 pg/ml (n = 5), 62.44 ± 15.51 pg/ml (n = 5), and 56.82 ± 12.78 pg/ml (n = 4) respectively. A significant reduction was found in the plasma VEGF levels 1 day after intravitreal injection of ranibizumab (P = 0.002). No significant differences were found between before and 1 week, 2 weeks, and 4 weeks after the injection. CONCLUSIONS: Intravitreal ranibizumab reduced plasma VEGF levels 1 day after injection in infants with ROP. This effect disappeared 1 week after the injection. Intravitreal ranibizumab did not induce prolonged systemic VEGF suppression.

A new method to predict anatomical outcome after idiopathic macular hole surgery.

PURPOSE: To investigate whether a new macular hole closure index (MHCI) could predict anatomic outcome of macular hole surgery. METHODS: A vitrectomy with internal limiting membrane peeling, air-fluid exchange, and gas tamponade were performed on all patients. The postoperative anatomic status of the macular hole was defined by spectral-domain OCT. MHCI was calculated as (M+N)/BASE based on the preoperative OCT status. M and N were the curve lengths of the detached photoreceptor arms, and BASE was the length of the retinal pigment epithelial layer (RPE layer) detaching from the photoreceptors. Postoperative anatomical outcomes were divided into three grades: A (bridge-like closure), B (good closure), and C (poor closure or no closure). Correlation analysis was performed between anatomical outcomes and MHCI. Receiver operating characteristic (ROC) curves were derived for MHCI, indicating good model discrimination. ROC curves were also assessed by the area under the curve, and cut-offs were calculated. Other predictive parameters reported previously, which included the MH minimum, the MH height, the macular hole index (MHI), the diameter hole index (DHI), and the tractional hole index (THI) had been compared as well. RESULTS: MHCI correlated significantly with postoperative anatomical outcomes (r = 0.543, p = 0.000), but other predictive parameters did not. The areas under the curves indicated that MHCI could be used as an effective predictor of anatomical outcome. Cut-off values of 0.7 and 1.0 were obtained for MHCI from ROC curve analysis. MHCI demonstrated a better predictive effect than other parameters, both in the correlation analysis and ROC analysis. CONCLUSIONS: MHCI could be an easily measured and accurate predictive index for postoperative anatomical outcomes.

Large scale fabrication of well-aligned CdS/p-Si shell/core nanowire arrays for photodetectors using solution methods.

We report a facile approach for the preparation of the vertically aligned, large scale CdS/p-Si shell/core nanowire heterojunction arrays based on successive ionic layer adsorption and reaction deposition. The results indicate that the rectifying characteristics of CdS/Si shell/core nanowire arrays can be tailored by changing the number of SILAR cycles, and the CdS/Si shell-core nanowire heterojunctions have good photo-sensitivity (the ratio of photocurrent to dark current could reach 14.96 at -1 V reverse bias) under AM 1.5 (1 Sun) illumination. Furthermore, the electron transport mechanism across the CdS/Si nano-heterojunctions is also discussed in detail. This reported CdS/p-Si shell/core nanowire structure offers a generic approach for the integration of new functional materials for photo-electronics applications.

Clinical features and prognosis of eyeball rupture: eye injury vitrectomy study.

BACKGROUND: The objective of the study was to delineate clinical characteristics, surgical interventions, anatomic and visual outcomes of ruptured eye balls after trauma, and establish the prognostic indicators, which can assist clinicians in making correct surgical decisions during globe exploration for ruptured eyes. DESIGN: The study design used was a multicentre prospective cohort study, including six university-affiliated tertiary hospitals. PARTICIPANTS: We selected 242 cases of ruptured globe from the Eye Injury Vitrectomy Study database, until 31 December 2012. METHODS: All selected cases underwent vitreoretinal surgery, enucleation or evisceration, and were followed up for at least 6 months. Age, visual acuity (VA) after injury, ocular trauma zone, time to surgery, corneal laceration, scleral wound, extrusion of iris or lens, ciliary body damage, intraocular haemorrhage, retinal detachment or defect, proliferative vitreoretinopathy (PVR) and choroidal damage were the predisposing factors evaluated by logistic regression models. MAIN OUTCOME MEASURES: We compared the pre-surgical indicators between cases of anatomically restored eyes with VA of 4/200 or better, or eyes with initial no light perception restored light perception or better, and cases of VA worse than 4/200, silicone oil-sustained eyes, phthisis or enucleation. RESULTS: Nearly 40% of cases with ruptured globe were anatomically restored through vitreoretinal surgery. The closed-funnel retinal detachment or extensive retinal loss (odds ratio [OR] = 3.38, P = 0.026), PVR-C (OR = 3.45, P = 0.008), and choroidal damage (OR = 4.20, P = 0.004) were correlated with poor outcomes. CONCLUSION: The closed-funnel retinal detachment or extensive retinal loss, PVR-C, and choroidal damage are the risk factors for unfavourable outcomes in globe ruptures.

[Study on solid dispersion of precipitated calcium carbonate-based oleanolic acid].

Oleanolic acid-precipitated calcium carbonate solid dispersion was prepared by using solvent evaporation method. The microscopic structure and physicochemical properties of solid dispersion were analyzed using differential scanning calorimetry and scanning electron microscopy (SEM). And its in vitro release also was investigated. The properties of the precipitated calcium carbonate was studied which was as a carrier of oleanolic acid solid dispersion. Differential scanning calorimetry analysis suggested that oleanolic acid may be present in solid dispersion as amorphous substance. The in vitro release determination results of oleanolic acid-precipitated calcium carbonate (1: 5) solid dispersion showed accumulated dissolution rate of.oleanolic acid was up to 90% at 45 min. Accelerating experiment showed that content and in vitro dissolution of oleanolic acid solid dispersion did not change after storing over 6 months. The results indicated that in vitro dissolution of oleanolic acid was improved greatly by the solid dispersion with precipitated calcium carbonate as a carrier. The solid dispersion is a stabilizing system which has actual applied value.

Apelin in epiretinal membranes of patients with proliferative diabetic retinopathy.

PURPOSE: Formation of epiretinal membranes (ERMs) in the posterior fundus results in visual impairment. ERMs have been associated with numerous clinical conditions, including proliferative diabetic retinopathy (PDR), a neovascular disease. Apelin has been identified as a novel angiogenesis contributor. The aim of this study was to investigate the correlation between apelin and ERMs after PDR. METHODS: ERM samples were obtained by vitrectomy from 12 subjects with PDR (aged 57±6 years; duration of diabetes 16±7 years), and 12 subjects with idiopathic ERM (aged 68±5 years). The samples were processed for immunohistochemistry and reverse transcription-PCR (RT-PCR). We also analyzed samples from patients with PDR who received an intravitreal injection of bevacizumab (IVB) before vitrectomy. RESULTS: The mRNA expression of apelin was significantly higher in the PDR ERMs than in the idiopathic ERMs. Accordingly, immunohistochemical analysis revealed strong expression of apelin in all eight PDR ERMs without IVB, and was double-labeled with glial fibrillary acidic protein antibody (GFAP), platelet endothelial cell adhesion molecule-1 (CD31), cytokeratin (CK) and vascular endothelial growth factor (VEGF) but not with fibronectin. They were mainly located in the adventitia. In contrast, the expression of apelin was lower in the PDR ERMs after IVB and the idiopathic ERMs. CONCLUSIONS: The results showed that apelin was involved in the formation of ERMs and promoted the formation of adventitia, including glial, endothelial, and RPE cells. Bevacizumab blocked the expression of apelin and regressed gliosis and angiogenesis.

The effect of intravitreal bevacizumab injection as the initial treatment for Coats' disease.

BACKGROUND: In Coats' disease, the most recent development in the treatment has been the intravitreal injection of anti-VEGF agents. The purpose of this article was to evaluate the effect of intravitreal bevacizumab as the initial treatment for Coats' disease in children and adults. METHODS: The study included 14 pediatric patients and five adult patients with Coats' disease. They were treated with intravitreal bevacizumab (1.25 mg/0.05 ml) as the initial treatment, combined with or without other treatments. The analyses included the evaluation of basic clinical conditions. RESULTS: In the pediatric group, after a mean of 9.1 months of follow-up, the differences in visual acuity were significant for the comparisons between the baseline examination and the follow-up examinations carried out at weeks 6, 12, and 24 after the baseline (P = 0.006, P = 0.004, P = 0.005 respectively). Vitreoretinal fibrosis was observed in three patients (n = 3, 21.4 %), among whom two showed fibrosis before treatment. All of the pediatric patients showed a resolution of fluid and exudation, and regression of the telangiectasia. In the adult group, after a mean of 10.6 months of follow-up, the differences in visual acuity were not statistically significant (P > 0.05) between the baseline and follow-up examinations. Vitreoretinal fibrosis (n = 2, 40 %) was observed in two patients who both showed fibrosis before treatment. All of the adult patients showed a resolution of fluid and exudation, and regression of the telangiectasia. The differences in the change of BCVA between children and adults were not significant (P > 0.05) during the follow-up examinations. CONCLUSION: The intravitreal injection of bevacizumab as the initial treatment is associated with a measurable gain in visual acuity in patients with Coats' disease. Resolution of the subretinal fluid and exudation, and regression of the telangiectasia were observed in both pediatric and adult patients. Vitreoretinal fibrosis may be one of the natural courses of Coats' disease, and it remains uncertain whether bevacizumab accelerates the fibrosis phenomenon.

[Effect of spray drying process on physical properties and dissolution of tanshinone].

In order to improve the dissolution in vitro of components by processing tanshinone with the pray drying method, the physical properties of tanshinone power was analyzed by BET, differential scanning calorimetry, scanning electron microscopy and X-ray powder diffraction, and its dissolution in vitro was also investigated. The results of characterization showed decreased power size and increased specific surface area of tanshinone powder, and its existence in an amorphous state. Within 4 h, the accumulated dissolutions of tanshinone I and tanshinone II(A) in components of tanshinone reached 78.3%, 81.9%, respectively. Therefore, the spray-drying method was conducive to enhance the dissolution of components of tanshinone.

[Preparation of baicalin colon-specific solid dispersion and evaluation on its in vitro release].

OBJECTIVE: To prepare pH-dependent baicalin colon-specific solid dispersion, with the aim of colon-specific delivery and rapid drug release. METHOD: Baicalin-eudragit S100 solid dispersion was prepared by using the solvent method. The microscopic structure and physicochemical properties were analyzed by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and infrared spectroscopy (IR). And its in vitro release was also investigated. RESULT: The results of DSC and XRD analysis suggested that baicalin may be dispersed in solid dispersion in the amorphous state. IR results indicated a non-covalent bond effect may exist between baicalin and eudragit S100. The results of in vitro release determination showed that very few baicalins in pH 1.2 diluted hydrochloric acid solution for 2 h at the baicalin-eudragit S100 ratio of 1 : 6. The accumulated dissolution rate was less than 15% in pH 6.8 phosphate buffer solution for 4 h, but exceeding 90% in pH 7.6 phosphate buffer solution for 1 h. CONCLUSION: The prepared baicalin-eudragit S100 solid dispersion could achieve the objective of colon-specific delivery and rapid drug release, and helps increase the concentration of baicalin in colons.

[Preparation of baicalin-chitooligosaccharide compound and its characterization].

To apply chitooligosaccharide in the preparation of baicalin compound, in order to increase the drug dissolution in vitro, and investigate the basic property of the compound. Baicalin-chitooligosaccharide compound was prepared by using the solvent method. The structure and physicochemical properties of compound were analyzed by using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and infrared vibrational spectrum (IR), and its dissolution behavior was also investigated. The results showed that the compound prepared at baicalin-chitooligosaccharide molar ratio of 1 : 1 could significantly improve the dissolution of baicalin. The results of DSC and XRD analysis suggested that baicalin may exist in an amorphous state. IR results indicated the interaction between baicalin and chitooligosaccharide. The baicalin-chitooligosaccharide compound could significantly improve dissolution in vitro of drug.

Transcriptional regulation of the Japanese flounder Cu,Zn-SOD (Jfsod1) gene in RAW264.7 cells during oxidative stress caused by causative bacteria of edwardsiellosis.

Edwardsiellosis is one of the most important bacterial diseases in fish, sometimes causing extensive economic losses in the aquaculture industry. Our previous studies demonstrated that the Cu,Zn-SOD (sod1) activity has significantly increased in Japanese flounder, Paralichthys olivaceus, hepatopancreas infected by causative bacteria of edwardsiellosis Edwardsiella tarda NUF251. In this study, NUF251 stimulated intracellular superoxide radical production in mouse macrophage RAW264.7 cells, which was reduced by N-acetylcysteine. This result suggests that NUF251 infection causes oxidative stress. To evaluate the regulatory mechanism of Jfsod1 at transcriptional levels under oxidative stress induced by NUF251 infection, we cloned and determined the nucleotide sequence (1124 bp) of the 5'-flanking region of the Jfsod1 gene. The sequence analysis demonstrated that the binding sites for the transcription factors C/EBPα and NF-IL6 involved in the transcriptional regulation of the mammalian sod1 gene existed. We constructed a luciferase reporter system with the 5'-flanking region (-1124/-1) of the Jfsod1 gene, and a highly increased transcriptional activity of the region was observed in NUF251-infected RAW264.7 cells. Further studies using several mutants indicated that deletion of the recognition region of NF-IL6 (-272/-132) resulted in a significant decrease in the transcriptional activity of the Jfsod1 gene in NUF251-infected RAW264.7 cells. In particular, the binding site (-202/-194) for NF-IL6 might play a major role in upregulating the transcriptional activity of the 5'-flanking region of the Jfsod1 gene in response to oxidative stress induced by NUF251 infection. These results could be provided a new insight to understand the pathogenic mechanism of causative bacteria of edwardsiellosis.

Quality improvement of threadfin bream (Nemipterus virgatus) surimi-gel using soy protein as a natural food additive.

Previously, we identified sarcoplasmic serine proteinase (SSP) as a modori-inducing proteinase from threadfin bream belly muscle. In this study, we investigated the autolytic activity of commercial threadfin bream surimi under modori-inducing conditions. High autolytic activity was detected in commercial surimi and was inhibited by a soybean trypsin inhibitor, indicating that SSP still remained in the commercial surimi. The effects of soy protein, defatted soy protein (DSP) and isolated soy protein (ISP), on SSP activity and surimi-gel properties were evaluated. The results showed that the modori phenomenon was induced at 70 °C, and that both DSP and ISP suppressed SSP activity and strengthened the breaking strength and breaking distance of the modori-induced gel. Surimi-gel with DSP performed better on gel whiteness than that of ISP, and 1 g/kg DSP had optimal gel properties. In conclusion, soy protein proved to be a good natural food additive for surimi-gel production of threadfin bream.