Guest-Induced Reversible Single-Crystal-to-Single-Crystal Transformation Involving Displacement of 2D Layers and Spin Crossover Behavior Change in a Hofmann-Type Coordination Polymer.

A novel two-dimensional (2D) Hofmann-type coordination polymer, {FeII(PyHbim)2[Pd(CN)4]}·2CH3OH [1·2CH3OH, PyHbim = 2-(4-pyridyl)benzimidazole], has been synthesized, which can undergo a spontaneous guest exchange, transforming to 1·2H2O in a single-crystal-to-single-crystal (SCSC) manner, shifting from orthorhombic Cmmm to monoclinic C2/m involving the displacement of 2D layers. The solvent-induced SCSC transformation process was reversible and verified through powder X-ray diffraction (PXRD) and single-crystal X-ray crystallography analyses. Both 1·2CH3OH and 1·2H2O exhibit complete and abrupt spin crossover (SCO) behaviors in two steps, while their SCO temperature ranges drastically shift by ca.100 K, spanning room temperature, owing to different intermolecular interactions resulting from diverse interlayer packing manners and host-guest interactions. Besides, a structural phase transition is observed in 1·2CH3OH, contributing to the two-step spin transition.

Fabrication and Process Optimization of Chinese Fir-Derived SiC Ceramic with High-Performance Friction Properties.

In this study, a novel friction material with biomass-ceramic (SiC) dual matrixes was fabricated using Chinese fir pyrocarbon via the liquid-phase silicon infiltration and in situ growth method. SiC can be grown in situ on the surface of a carbonized wood cell wall by mixing and calcination of wood and Si powder. The samples were characterized using XRD, SEM, and SEM-EDS analysis. Meanwhile, their friction coefficients and wear rates were tested to study their frictional properties. To explore the influence of crucial factors on friction performance, response surface analysis was also conducted to optimize the preparation process. The results showed that longitudinally crossed and disordered SiC nanowhiskers were grown on the carbonized wood cell wall, which could enhance the strength of SiC. The designed biomass-ceramic material had satisfying friction coefficients and low wear rates. The response surface analysis results indicate that the optimal process could be determined (carbon to silicon ratio of 3:7, reaction temperature of 1600 °C, and 5% adhesive dosage). Biomass-ceramic materials utilizing Chinese fir pyrocarbon could display great promise to potentially replace the current iron-copper-based alloy materials used in brake systems.

A fluorescent probe derived from Berberrubine for detecting hydrogen polysulfide in food samples.

In this work, we chose the fluorophore Berberrubine to develop a selective probe for hydrogen polysulfide (H2Sn), and applied it into the detection in both food samples and living cells. The developed probe, HER9SS, suggested practical steadiness and serviceability, especially for multi-scene detection. The detecting system was stable in relatively wide pH (7.0-11.0) and temperature (25-45 °C) ranges. Both the storage of BER9SS in solid or in solution could maintain the steadiness over 7 d. BER9SS also indicated advantages including rapid response (within 15 min), high sensitivity (LOD = 0.02 µM; LOQ = 0.01 µM), long linear range (0-15.0 equivalent) and high selectivity among competing analytes. The recovery ranging in 95.23% - 104.8% in the applications in food sources samples (including water and plants) and food samples inferred the practical potential of BER9SS. In biological imaging, BER9SS could achieve both the dose-dependent monitoring and the ß-lapachone-induced generation of H2Sn. Therefore, the information in this work might be useful for the development of fluorescent probes from natural products for multi-scene applications in future, especially with the corresponding attentions on the practicability and serviceability.

Reversible three equal-step spin crossover in an iron(ii) Hofmann-type metal-organic framework.

A novel bent ligand-pillared three-dimensional Hofmann-type metal-organic framework, [FeII(Hbpt)Pt(CN)4]·1/2Hbpt·1/2CH3OH·5/2H2O [1, Hbpt = 4,4'-(1H-1,2,4-triazole-3,5-diyl) dipyridine], was synthesized and crystallographically and magnetically characterized, which showed incomplete three-step spin-crossover behavior with a reversible three equal-step sequence of HS1.00 ↔ HS0.75LS0.25 ↔ HS0.5LS0.5 ↔ HS0.25LS0.75.

Hysteretic Two-Step Spin-Crossover Behavior in Two Two-Dimensional Hofmann-Type Coordination Polymers.

The reaction of ferrous salts and square-planar tetracyanometallates [MII (CN)4 ]2- (M=Pd, Pt) with ligand 4-(1H-pyrazol-3-yl)pyridine (Hppy) resulted in the formation of two two-dimensional (2D) Hofmann-like coordination polymers (CPs) with the general formula of {FeII (Hppy)2 [MII (CN)4 ]}⋅H2 O (M=Pd for 1Pd , Pt for 1Pt ). The two CPs have been studied by variable-temperature single-crystal X-ray crystallography, differential scanning calorimetry, and magnetic measurements. Polymers 1Pd and 1Pt are isostructures, in which the FeII atoms are equatorially coordinated with [MII (CN)4 ]2- to form 2D undulating layers and axially coordinated with Hppy ligands. Both compounds undergo cooperative, complete spin crossover (SCO), with characteristic abrupt and remarkable two equal steps, featuring hysteresis widths of 14 K and 19 K (1Pd ) and 17 and 23 K (1Pt ) for the two steps. The SCO cooperativity may result from the hydrogen bonds and π⋅⋅⋅π interactions within and between such 2D layers, and the two-step SCO behavior is accompanied with phase transitions.

Pigment dispersion syndrome and pigmentary glaucoma after secondary sulcus transscleral fixation of single-piece foldable posterior chamber intraocular lenses in Chinese aphakic patients.

PURPOSE: To describe secondary pigment dispersion syndrome (PDS) and pigmentary glaucoma after secondary sulcus transscleral fixation of 1-piece hydrophobic acrylic foldable posterior chamber intraocular lenses (PC IOLs) in aphakic patients in a Chinese population. SETTING: Department of Ophthalmology, Qingdao Municipal Hospital, Qingdao, China. DESIGN: Retrospective case series. METHODS: This chart review included eyes that had secondary sulcus transscleral fixation of a 1-piece hydrophobic acrylic foldable PC IOL (Tecnis ZCB00) between March 2011 and March 2014. The patients' demographic data, clinical data, postoperative complications, intervals between initial surgery and the onset of PDS, pigmentary glaucoma occurrences, and findings on slitlamp biomicroscopy, gonioscopy, and ultrasound biomicroscopy (UBM) were recorded. RESULTS: The study comprised 23 consecutive eyes of 21 patients. Seventeen eyes of 16 patients were diagnosed with PDS, and 7 eyes of 6 patients were diagnosed with pigmentary glaucoma. The slitlamp examination and UBM showed that the location between the IOL optic and the posterior surface of the iris was very close. Slitlamp examination of the anterior chamber angle using a gonioscope showed dense pigment deposition on the IOL surfaces. A reverse pupillary block was found in 10 eyes of 9 patients. Other postoperative complications included intraocular hemorrhage, pupillary capture of the IOL optic, IOL tilt, IOL decentration, IOL dislocation, and suture erosion. CONCLUSION: The 1-piece hydrophobic acrylic foldable PC IOL was not suitable for sulcus transscleral fixation because of a high incidence of PDS and pigmentary glaucoma after surgery in a Chinese population.

Robust Cluster Building Unit: Icosanuclear Heteropolyoxocopperate Templated by Carbonate.

The encapsulation of carbonate derived from atmospheric CO2 has resulted in an icosanuclear heteropolyoxocopperate, isolated as a metal-organic 1D chain, 2D sheet, or 3D framework, in which the Cu20 nanocluster represents the first eight-capped α-Keggin polyoxometalate with the late-transition-metal Cu(II) as the polyatom, CO3(2-) as the heteroanion, and OH(-) and suc(2-) or glu(2-) (H2suc=succinic acid; H2glu=glutaric acid) as the terminal ligands, which suggests a conceptual similarity to classical polyoxometalates. Even in the presence of competitive SO4(2-) in the assembly system, the CO3(2-) anion is still captured as a template to direct the formation of the Cu20 nanocluster, which indicates the stronger templation ability of CO3(2-) compared with SO4(2-). When other aliphatic dicarboxylates, such as glutaric acid, were used as ligands, the CO3(2-)-templated Cu20 nanocluster was maintained and acted as a cluster building unit (CBU) to be linked by two glutarate bridges to generate a distinct 1D metal-organic chain. This report presents not only a rare example of a huge anion-templated transition-metal cluster, but also its use as a robust CBU to construct novel coordination architectures. Variable-temperature magnetic susceptibility studies revealed that an antiferromagnetic interaction exists within the Cu20 nanocluster. The correlation between the coordination structure and the electron paramagnetic resonance spectra recorded of both powder and single-crystal samples are discussed in detail.

Subretinal heterotopic respiratory epithelium: a case report and literature review.

A 51-year-old female underwent vitrectomy surgery to remove a group of spherical subretinal tumors beneath the detached retina. Hematoxylin and eosin staining and immunohistochemical findings showed that the characteristics of the tumor were consistent with a subretinal heterotopic respiratory epithelium. This is the first report of a respiratory epithelial heterotopia located in the subretinal space.

Synthesis of two triarylboron-functionalized metal-organic frameworks: in situ decarboxylic reaction, structure, photoluminescence, and gas adsorption properties.

Two 3D noninterpenetrating porous metal-organic frameworks (PMOFs) [Cd3(L(1))2(DMA)2]·DMA [1, H3L(1) = tris(p-carboxylic acid)tridurylborane] and [Zn3(L(2))3(H2O)2]·5H2O·2EtOH [2, H2L(2) = 4,4'-((2,3,5,6-tetramethylphenyl)boranediyl)bis(2,3,5,6-tetramethylbenzoic acid)] were synthesized by employment of a C3-symmetric ligand (H3L(1)) to assembly with Cd(NO3)2 or Zn(NO3)2. Complex 1 exhibits a (3, 6)-connected topological network based on a Cd3 cluster and Y-shaped trinodal organic linker. Complex 2 shows a 6-connected topology, since in situ decarboxylic reaction of the initial H3L(1) occurred to generate a new ligand, H2L(2), which can be considered as a linear linker. Both 1 and 2 exhibit blue fluorescence. Significantly, complex 1 with larger channels is unstable upon the removal of guest molecules. In contrast, activated 2 exhibits higher stability and permanent porosity.

Achieving a rare breathing behavior in a polycatenated 2D to 3D net through a pillar-ligand extension strategy.

Through a pillar-ligand extension strategy, a rare breathing behavior in polycatenated 2D→3D nets has been achieved. Three variants exhibit interesting sorption properties that range from non-breathing to breathing behaviors, which is influenced by the angles between the pillars and the single honeycomb layers. The increase in pillar length does not lead to an increase in polycatenation multiplicity, which is controlled by the length of intralayer tripodal carboxylate. It also does not induce obviously expanded interlayer separations but occupies much more the free voids, and as a consequence, a smaller pore volume is obtained. This suggests that in 2D→3D polycatenated bilayer metal-organic frameworks, the porosity is not always enhanced by increasing the length of the interlayer pillars with the intralayer linker remaining unchanged.

Unusual N-H activation of 2-aminopyrimidine: supramolecular assembly into an Ag(I) metal-organic framework.

A rare example of coordination at the amino group of NH2 pym (2-aminopyrimidine) relevant to N-H activation is described that leads to a novel Ag(I) -imide 3D metal-organic framework (MOF). The coordination of Ag(I) to NH2 pym produced an electron-withdrawing effect and thus increased its acidity, which facilitated the N-H activation and the subsequent formation of the Ag-imide bond. A cooperative metalation/deprotonation process for the N-H activation of NH2 pym is suggested. Interestingly, photoluminescence of 1 is switched on at the low temperature of 77 K.

A tubular europium-organic framework exhibiting selective sensing of Fe3+ and Al3+ over mixed metal ions.

A luminescent europium-organic framework with tubular channels based on the H4BTMIPA ligand (H4BTMIPA = 5,5'-methylenebis(2,4,6-trimethylisophthalic acid)) was assembled and characterized. The [H2N(CH3)2](+) ions as counterions are located in the channels. The cation exchange between [H2N(CH3)2](+) and metal ions resulted in complex that can selectively sense Fe(3+) and Al(3+) ions through fluorescence quenching and enhancement, respectively.

A one-dimensional coordination polymer based on a di-Schiff base supported trinuclear CuII subunit.

A novel one-dimensional Cu(II) coordination polymer, catena-poly[bis(µ(4)-3-{[2-(3-hydroxy-2-oxidobenzylidene)hydrazinylidene]methyl}benzene-1,2-diolato)dimethanoltricopper(II)], [Cu(3)(C(14)H(10)N(2)O(4))(2)(CH(3)OH)(2)](n), (I), was constructed with a di-Schiff base supported centrosymmetric trinuclear Cu(II) subunit. In the subunit, two peripheral symmetry-related Cu(II) cations have square-pyramidal CuNO(4) geometry and the central third Cu(II) cation lies on an inversion centre with octahedral CuN(2)O(4) geometry. In (I), each partially deprotonated di-Schiff base 3-{[2-(3-hydroxy-2-oxidobenzylidene)hydrazinylidene]methyl}benzene-1,2-diolate ligand (Hbcaz(3-)) acts as a heptadentate ligand to bind the Cu(II) centres into chains along the a axis. A centrosymmetric Cu(2)O(2) unit containing an asymmetrically bridging O atom, being axial at one Cu atom and equatorial at the other Cu atom, links the trinuclear Cu(II) subunit into a one-dimensional chain, which is reinforced by intramolecular phenol-methanol O-H...O and methanol-phenolate O-H...O hydrogen bonds. Interchain π-π stacking interactions between pyrocatechol units, with a distance of 3.5251 (18) Å, contribute to the stability of the crystal packing.

Simotang enhances gastrointestinal motility, motilin and cholecystokinin expression in chronically stressed mice.

AIM: To investigate the effect of Simotang (Decoction of Four Powered Drugs) on gastrointestinal motility, motilin and cholecystokinin expression in chronically stressed mice. METHODS: Forty mice were randomly divided into control group, stress group (model group), mosapride group and Simotang group, 10 in each group. A variety of unpredictable stimulations were used to induce chronic stress in mice. Then, the mice were treated with distilled water, mosapride or Simotang for 7 d. Gastric emptying and intestinal propulsion function were detected. Serum level of motilin was measured by enzyme-linked immunosorbent assay. Expression of cholecystokinin (CCK) in intestine, spinal cord and brain of mice was detected by immunohistochemistry and semi-quantitative reverse transcription polymerase chain reaction, respectively. RESULTS: Simotang improved the gastric emptying and intestinal propulsion in chronically stressed mice. Furthermore, the serum motilin level was significantly higher and the expression levels of CCK-positive cells and genes were significantly lower in intestine, spinal cord and brain of Simotang group than in those of model group (P < 0.05). No significant difference was found in serum motilin level and expression levels of CCK-positive cells and genes between the mosapride and Simotang groups. CONCLUSION: Simotang enhances the gastrointestinal motility in chronically stressed mice by regulating the serum motilin level and the expression of cholecystokinin.

[Paying attention to the research of apoptosis of retinal photoreceptor cells in retinal photochemical damage].

Many retinal degeneration diseases, such as retinitis pigmentosa and age-related macular degeneration, the main pathologic character of such retinal degeneration diseases is apoptosis of retinal photoreceptor cells. Recently, It is still short of effective treatment. Evidence from epidemiological studies and from experiments indicates that excessive light exposure may promote retinal degeneration, in which photoreceptor death by apoptosis leads to loss of vision. It is, therefore, of critical importance to pay more attention to further understanding of retinal photochemical damage and the apoptosis of retinal photoreceptor cells.

[Relationship between vasculogenic mimicry and clinical pathological characters in retinoblastoma].

OBJECTIVE: To explore if vasculogenic mimicry (VM) exists in retinoblastoma (Rb) and to explore the clinical significance of VM. METHODS: It was an experimental study. Sixty Rb specimens with complete clinical and prognostic data were collected. Periodic acid-Schif staining and immunohistochemical staining of CD34 were conducted to explore if VM exists in those Rb specimens. The expression of HIF-1alpha and VEGF were examined by immunohistochemical staining. The expression of CD34 endothelial antigen was used to label the neo-microvessels. Microvessel density (MVD) in retinoblastoma tissues was calculated. RESULTS: In HE staining slides, VM was present in Rb specimens and was formed by tumor cells but not endothelial cells. Red blood cells were present in the VM. VM existed in 18.33% (11/60) of the Rb specimens. Low R-E graded Rb specimens exhibited a higher VM positive rate than that in the high R-E graded Rb (chi(2) = 8.861, P < 0.05). The positive rate of VM was 4.34% in differentiated type of Rb and was 22.02% in undifferentiated type of Rb (chi(2) = 4.872, P < 0.05). HIF-1alpha and VEGF expressions in Rb with VM were significantly greater than those in Rb without VM (P = 0.001). The density of endothelial vessels correlated with VM. The mean MVD was 49.77 +/- 2.05 in Rb without VM and 36.53 +/- 1.15 in Rb with VM (P < 0.05). CONCLUSIONS: VM exists in Rb. Highly differentiated Rb exhibits more VM than that in less differentiated Rb. Expression of HIF-1alpha and VEGF is greater in Rb with VM, indicating that these factors may stimulate the occurrence of VM.

[Hydrogen peroxide induces expression and transcription of erythropoietin in the human retinal pigment epithelium cells].

OBJECTIVE: To investigate the expression of erythropoietin (EPO) in human fetal retinal pigment epithelium (hfRPE) cells exposed to oxidative stress induced by hydrogen peroxide (H(2)O(2)) and to study the mechanisms. METHODS: The hfRPE cells were isolated, cultured and identified. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) of the hfRPE cells were examined. The changes of level of mRNA and protein of EPO in hfRPE cells exposed to oxidative stress were measured by semi-quantitative RT-PCR and immunocytochemical staining techniques. RESULTS: H(2)O(2) could increase the content of MDA and inhibit the activity of SOD in hfRPE cells. RT-PCR detected a significant increase of EPO mRNA level in cultured hfRPE cells exposed to oxidative stress. The level of EPO mRNA in the hfRPE cells reached a peak when exposed to 600 micromol/L H(2)O(2), then decreased after exposing to 800 micromol/L H(2)O(2). The immunocytochemical study detected that the changes of the level of EPO protein were similar to that of EPO mRNA. CONCLUSION: Oxidation stress by exposed to H(2)O(2) induces significant increase of EPO expression of hfRPE cells. Expression of EPO may be related to the survival and tolerance of hfRPE cells.

[Clinical and pathological analysis of choroidal metastatic carcinoma].

OBJECTIVE: To study the clinical and pathological characteristics of choroidal metastatic carcinoma. METHODS: The clinical data, pathological character, primary tumor origin and histological classification of 18 patients with choroidal metastatic carcinoma were analyzed retrospectively. RESULTS: Most patients had severe visual impairment. Solid mass was seen in the posterior pole of the eyes in all 18 patients through ocular fundus examination, 8 cases had retinal detachment. B scan and CT examination found flat or irregular masses. MRI examination had been performed on 5 patients, high signal intensities on T1W and low signal intensities on T2W were found. Five patients were adenocarcinoma, 4 were squamous carcinoma and 3 were undifferentiated carcinoma through pathological examination. Primary tumor was lung carcinoma in 10 cases (55%) and breast carcinoma in 4 cases (22%). CONCLUSIONS: Rapid decrease of visual acuity, flat neoplasm in ocular fundus and secondary retinal detachment are the main clinical characteristics of choroidal metastatic carcinoma. The most common primary tumor is lung carcinoma and the most common histopathological classification is adenocarcinoma. Imaging examination is helpful for the diagnosis of choroidal metastatic carcinoma.

[The mechanism of accumulative oxidative injury by hydrogen peroxide on human retinal pigment epithelial cells].

OBJECTIVE: To explore the effects of oxidative injury induced by hydrogen peroxide on human retinal pigment epithelial (RPE) cells. METHODS: Cultured human RPE cells were treated by 600 micromol/L hydrogen peroxide (H2O2) for 1, 6, 12, 24 and 72 hours. Cell viability was assessed by the MTT assay. Apoptosis was assessed by Annexin V-fluorescein isothiocyanate/Propidium iodium (Annexin V-FITC/PI) staining. The expression of clusterin was assessed by Western blot. RESULTS: (1) The treatment of RPE cells with 600 micromol/L H2O2 caused a time-dependent decrease of cellular viability. (2) Apoptosis was detected in cultured human RPE cells treated with 600 micromol/L H2O2 for 6 hours. The number of apoptotic cells reached a maximum at 24th hour after being exposed to 600 micromol/L H2O2 (P < 0.05). (3) Western blot showed the expression of clusterin protein was demonstrated in 6 hours exposure to 600 micromol/L H2O2, a significantly increasing of clusterin expression was observed overtime (P < 0.01). Thereafter the expression of clusterin protein decreased at 24th hour after being exposed to 600 micromol/L H2O2. At 72nd hour, the expression of clusterin protein was quite weak. CONCLUSION: Hydrogen peroxide can inhibits RPE proliferation and induces apoptosis and aging gene expression;the result suggest that accumulative oxidative injury induced by hydrogen peroxide in RPE in vitro may be similar to the aging changes in vivo.

[Erythropoietin administration protects retina against light-induced retinal degeneration].

OBJECTIVE: To study whether recombinant human erythropoietin can pass through mice blood-retina barrier and the protective role in light-induced damage in retina. METHODS: After the injection of rHEPO, the content of rHEPO in 24 BALB/c mice retina was examined by enzyme linked immunosorbent assay (ELISA). 24 BALB/c mice were used to establish a light-induced damaged model, the difference of retina in rHEPO group and control group was compared using light microscope and TdT-mediated dUTP nick end labeling (TUNEL). RESULTS: The amount of retinal rHEPO in four deferent time points was (0.68 +/- 0.24) mU, (1.87 +/- 0.37) mU, (0.96 +/- 0.24) mU, (0.47 +/- 0.13) mU in 100 microg retinal total protein respectively by ELISA assay, there were statistical significances among groups. The density of rHEPO in the retina reached its peak at 4th hour after injection. Histology analysis: rHEPO group, at the 12th hour after light exposure the inner segment became condensed and disorganized. At the 36th hour the retina disorganized and vesiculated were seen in outer segments. At the 72nd hour the inner and outer segments were damaged more seriously and the outer nuclear layer became thinner and denser. On the 7th day, the retinal outer nuclear layer became thinner and condenses. rHEPO group showed a minimal damage in every time points but outer nuclear layer disorganized and vesiculated in inner and outer segments. No obvious changes in retinal thickness. The apoptotic cells were detected by TUNEL. At the 12th hour after light exposure, there were the apoptotic cells in outer nuclear layer near outer plexiform layer. At 36th hour the numbers of apoptotic cells were increased, however at the 72nd it was decreased obviously, only a few scattering apoptotic cells were revealed in the outer nuclear layer. Numbers of apoptotic cells between the rHEPO group and control group in outer nuclear layer were statistical significance (P < 0.01). CONCLUSIONS: rHEPO can pass through the mice blood-retina barrier and rHEPO has neuroprotective effect on mice retina. rHEPO may be used to treat degenerative retinal diseases.