Novel preparation of stable and highly photocatalytic Z-scheme Cs3PW12O40/Ag3PO4 photocatalysts for the photocatalytic degradation of organic contaminants in water.

The Cs3PW12O40/Ag3PO4 (CsPW/Ag3PO4) heterojunction photocatalyst in this study was prepared using a simple chemical precipitation method. Spherical CsPW particles were successfully deposited on Ag3PO4 nanocrystals, all the as-prepared samples are characterized by X-ray diffraction pattern (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV visible spectroscopy (UV-Vis), and X-ray photoelectron spectroscopy (XPS). The catalyst activity in relation to rhodamine B (RhB) degradation was evaluated under visible light (λ > 420 nm). The CsPW/Ag3PO4 heterojunction photocatalyst can effectively degrade RhB. The Z-scheme 3% CsPW/Ag3PO4 heterojunction photocatalyst has a higher photocatalytic ability compared with the single-component photocatalyst CsPW or Ag3PO4. The comparatively high photocatalytic performance can be attributed to the high matching of the energy band position and close interface contact, suggesting an enhanced separation efficiency of the photoinduced carriers of the CsPW/Ag3PO4 heterojunction photocatalyst. The reactive species trapping experiments demonstrated photogenerated holes (h+) and superoxide radicals (•O2-) to be the main active components of photocatalytic degradation. A possible photocatalytic mechanism is subsequently proposed.

Preparation and photocatalytic performance of UIO-66/La-MOF composite.

To improve the photocatalytic degradation efficiency of photocatalytic materials UIO-66 and La-MOFs under visible-light irradiation, a series of photocatalytic materials with La and Zr as metal centers and terephthalic acid (H2BDC) and 2-amino terephthalic acid (H2ATA) as organic ligands were prepared by solvothermal method. The photocatalytic materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-visible (UV-vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and Mott-Schottky test. The photocatalytic degradation performance to Rhodamine B of the catalysts was fully investigated. Results show that the H2ATA series had stronger visible-light absorption capacity and better photocatalytic performance. The 0.35 La/Zr-H2ATA composite showed the best photocatalytic degradation. The quenching experiments confirmed that the active species in the photocatalytic degradation were the holes and superoxide radicals. The possible mechanisms of the carrier migration paths in the energy level matching for La/Zr-H2BDC and La/Zr-H2ATA were also discussed in detail.

Efficient Electrochemical Water Oxidation Mediated by Pyridylpyrrole-Carboxylate Ruthenium Complexes.

Spurred by the rapid growth of Ru-based complexes as molecular water oxidation catalysts (WOCs), we propose novel ruthenium(II) complexes bearing pyridylpyrrole-carboxylate (H2ppc) ligands as members of the WOC family. The structure of these complexes has 4-picoline (pic)/dimethyl sulfoxide (DMSO) in [Ru(ppc)(pic)2(dmso)] and pic/pic in [Ru(ppc)(pic)3] as axial ligands. Another ppc2- ligand and one pic ligand are located at the equatorial positions. [Ru(ppc)(pic)2(dmso)] behaves as a WOC as determined by electrochemical measurement and has an ultrahigh electrocatalytic current density of 8.17 mA cm-2 at 1.55 V (vs NHE) with a low onset potential of 0.352 V (vs NHE), a turnover number of 241, a turnover frequency of 203.39 s-1, and kcat of 16.34 s-1 under neutral conditions. The H2O/pic exchange of the complexes accompanied by oxidation of a ruthenium center is the initial step in the catalytic cycle. The cyclic voltametric measurements of [Ru(ppc)(pic)2(dmso)] at various scan rates, Pourbaix diagrams (plots of E vs pH), and kinetic studies suggested a water nucleophilic attack mechanism. HPO42- in a phosphate buffer solution is invoked in water oxidation as the proton acceptor.

Neutral Cyclometalated Ir(III) Complexes with Pyridylpyrrole Ligand for Photocatalytic Hydrogen Generation from Water.

To explore structure-activity relationships with respect to light-harvesting behavior, a family of neutral iridium complexes [Ir(ppy)2(LR)] 1-4 (where ppy = 2-phenylpyridine, and N̂N = 2-(1H-pyrrol-2-yl)pyridine and its functionalized derivatives) were designed and synthesized. The structural modifications in metal complexes are accomplished through the attributions of electron-donating CH3 in 2, OCH3 in 3, and electron-withdrawing CF3 in 4. The structural analysis displays that the pyridylpyrrole acts as one-negative charged bidentated ligand to chelate the iridium center. The electrochemical and photophysical properties of these complexes were systematically studied. The neutral 1-4 as well as the ionic structurally analogous [Ir(ppy)2(bpy)](PF6) (5) were utilized as PSs in photocatalytic hydrogen generation from water with [Co(bpy)3](PF6)2 as catalyst and triethanolamine (TEOA) as electron sacrificial agent in the presence of salt LiCl. Complex 1 maintains activity for more than 144 h under irradiation, and the total turnover number is up to 1768. The electrochemical properties and the quenching reaction indicate the H2 generation by neutral complexes 1-4 is involved exclusively in the oxidative quenching process.

Convenient synthesis of three-dimensional hierarchical CuS@Pd core-shell cauliflowers decorated on nitrogen-doped reduced graphene oxide for non-enzymatic electrochemical sensing of xanthine.

A novel hybrid with three-dimensional (3D) hierarchical CuS@Pd core-shell cauliflowers decorated on nitrogen-doped reduced graphene oxide (CuS@Pd/N-RGO) has been prepared by a facile wet-chemical route without utilizing any template molecules and surfactants. The characterization results reveal that the 3D flower-like structure of CuS "core" is composed of interconnecting nanoplates, which is conductive to the loading of Pd nanoparticles' "shell" and results in the robust interaction between the core and shell for the formation of CuS@Pd cauliflowers. Anchoring such appealing CuS@Pd cauliflowers on the two-dimensional N-RGO can efficaciously inhibit the aggregation of CuS@Pd cauliflowers and accelerate the kinetics of xanthine oxidation. Benefiting from the multi-functional properties and unique morphology, the sensor constructed by CuS@Pd/N-RGO exhibits excellent performance for non-enzymatic detection of xanthine including a wide detection range of 0.7-200.0 µM (0.94 V vs. SCE), a low detection limit of 28 nM (S/N = 3), high reproducibility (relative standard deviation (RSD) = 4.1%), and commendable stability (retained 90% of the initial electrochemical responses after storage for 30 days), which is amongst the best of various electrochemical sensors reported for xanthine assays till date. Reliable and satisfying recoveries (95-105%, RSD ≤ 4.1%) are achieved for xanthine detection in real samples. The inspiring results make the uniquely structural CuS@Pd/N-RGO greatly promising in non-enzymatic electrochemical sensing applications. Graphical abstract A high-performance non-enzymatic xanthine sensor has been constructed by the three-dimensional hierarchical CuS@Pd core-shell cauliflowers decorated on nitrogen-doped reduced graphene oxide.

Synthesis of a novel cost-effective double-ligand Zr-based MOF via an inverted modulator strategy towards enhanced adsorption and photodegradation of tetracycline.

Developing visible-light response photocatalysts with high activity and adsorption alongside sustainability is vitally important to environmental restoration. Here, we fabricated a novel metal organic framework (MOF) with cost-effective double-ligands (fumaric acid and 2-aminoterephthalic acid as ligand precursors, denoted as MA-MOF) via a facile solvothermal method. Specifically, crystalline [Zr6O4(OH)4(fumarate)6] (MOF-801) can be only formed with monocarboxylic acids as modulators. Therefore, in the construction of crystalline double-ligand MA-MOF, the absence of monocarboxylic acid modulators successfully prevents the formation of crystalline MOF-801. Instead, the crystalline double-ligand MA-MOF is formed. Properties of MA-MOFs including the surface area, porosity, charge transfer resistance, and energy level position can be adjusted via altering the ratio of ligands. The optimal sample, MA-MOF2 (prepared with a molar ratio of fumaric acid and 2-aminoterephthalic acid being 2:1), shows a total 94.6% removal of tetracycline via adsorption and photodegradation, far exceeding the corresponding single-ligand counterparts. This work proposes an innovative inverted modulator strategy for constructing double-ligand MOFs.

Tuning the Fe/Co ratio towards a bimetallic Prussian blue analogue for the ultrasensitive electrochemical sensing of 5-hydroxytryptamine.

Lack of highly efficient, inexpensive, and easily available catalysts severely limits the practical applicability of electrochemically sensing assay towards 5-hydroxytryptamine (5-HT). Herein, four kinds of Fe-Co bimetallic Prussian blue analogues (FeCo-PBAs) with different molar ratios of Fe to Co were prepared using a simple coprecipitation method. Interestingly, Fe(III) in K3 [Fe(CN)6] can be reduced to Fe(II) by adding trisodium citrate dehydrate, which could offer a new clue to synthesize PBAs with Fe(II) core ions. With the optimizational FeCo-PBA synthesized at a 0.5/1 M ratio of Fe to Co as an electrocatalyst, the constructed sensor shows excellent comprehensive performance for the 5-HT assay with a high sensitivity of 0.856 µA µM-1 and an ultralow detection limit of 8.4 nM. Under the optimum conditions, linearity was obtained in the ranges of 0.1-10.0 µM and 10.0-200.0 µM and preferable recoveries ranged from 97.8% to 103.0% with relative standard deviation (RSD) < 4.0%. The integrated properties of FeCo-PBA can be comparable to previously reported electrocatalysts for the 5-HT assay including noble metal-based and expensive carbon (graphene and carbon nanotubes)-based electrocatalysts. The proposed sensor also exhibits outstanding selectivity, reproducibility, and practicality for real sample analyses. This work is the first report on the PBA-based sensor for the 5-HT assay, verifying the practicability of this high-performance sensor for the 5-HT assay.

Long-term culture and cryopreservation of interstitial cells of Cajal.

OBJECTIVE: Interstitial cells of Cajal (ICCs) in the gastrointestinal tract generate and propagate slow waves and mediate neuromuscular neurotransmission. Damage to ICCs has been described in several gastrointestinal motor disorders, and although many studies have examined ICCs in culture, they have been largely limited to freshly dissociated cells or short-term cultures. An efficient and reliable method to establish a source of ICCs is much needed. The aim of this study was to investigate methods for culturing, subculturing, cryopreservation, and recovery of ICCs. METHODS: ICCs were derived from intestinal segments of domestic rabbits, and immunohistochemistry for c-Kit was used to identify ICCs in culture and after recovery. Recovered ICCs were also examined for motilin receptor expression. RESULTS: Optimal conditions for ICC culture and cryopreservation were based on cell growth curves and MTT assay. On the basis of these findings, recovered cells were cultured for 7 days and then sorted via flow cytometry based on c-Kit immunoreactivity. The percent of c-Kit positive cells was 64.3%, and the number of ICCs sorted was 6.7 × 10(5). Reverse-transcription polymerase chain reaction and western blotting verified motilin receptor expression in c-Kit-positive ICCs. CONCLUSIONS: This is the first study to describe the culture, passage, and recovery of ICCs and to show motilin receptor expression. Our results suggest that ICCs play an important role, at least in some species, in initiating the migrating myoelectric complex induced by motilin.

Immunophenotype of Chinese patients with T-lineage acute lymphoblastic leukemia and its association to biological and clinical features.

BACKGROUND/AIMS: To investigate the immunophenotype of 46 Chinese patients with T-lineage acute lymphoblastic leukemia (T-ALL) and its association with biological and clinical features. METHODS: 46 patients with T-ALL were immunophenotyped by flow cytometry, and 30 cases were also subjected to karyotype analysis by R-banding technology. The clinical and biological characteristics of T-ALL patients between MyAg+ and MyAg- groups were analyzed. RESULTS: Myeloid antigen (MyAg) expression was documented in 41.3% of the 46 T-ALL cases. Abnormal karyotypes were detected in 17 out of 30 (56.7%) cases. Our data showed that the median lowest white blood cell (WBC) count and lowest hemoglobin level, higher CD34 positivity, and a lower proportion of patients with splenomegaly were found to be correlated with MyAg+ T-ALL. No statistical difference was noted in the complete remission (CR) rate, relapse rate, induction death rate or total death rate among MyAg+ and MyAg- patients. In our cohort, none of the antigens tested affected the CR rate after the first induction. CONCLUSION: Our results indicate that MyAg expression in patients with T-ALL was not associated with adverse presenting clinical and biological features as well as response to induction treatment. The expression of surface antigens had no impact on initial chemotherapy CR achievement.

Immunophenotypic, cytogenetic, and clinical features of 207 cases of childhood acute lymphoblastic leukemia in china.

OBJECTIVE: In this study, we investigated the immunophenotypic subtype profiles of 207 Chinese children with acute lymphoblastic leukemia (ALL) and its association with cytogenetics and clinical features. METHODS: A total of 207 children with ALL were immunophenotyped by 4-color flow cytometry using a panel of monoclonal antibodies. Among the 207 patients enrolled in this study, 146 cases were also subjected to karyotype analysis by R-banding technology. RESULTS: Of the 207 children with ALL, 11.6% were identified as T-ALL and 88.4% as B-ALL. Among B-ALL, 6.6% were identified as Pro-B ALL, 67.2% as Com-B ALL, 24.0% as Pre-B ALL, and 2.2% as mature-B ALL. Myeloid antigen (MyAg) expression was documented in 42.5% of the 207 cases analyzed and CD13 was the most commonly expressed MyAg (31.4%). No difference was observed in the expression of MyAg between the groups of patients with T-ALL (41.7%) and B-ALL (42.6%). Abnormal karyotypes were detected in 84 of 146 (57.5%) children. The clinical and biological characteristics of ALL patients between the MyAg⁺ and MyAg⁻ groups showed that a higher percentage of patients with high WBC count (>50×109/L) and higher CD34 positivity were found to be correlated with MyAg⁺ ALL. CONCLUSIONS: Our results indicate that the distribution of ALL in Chinese children was similar to the general distribution pattern in other countries. Unlike previous studies, we found that the expression of MyAg in children with T-ALL and B-ALL was comparable, and the percentage of patients with a high WBC count (>50×109/L) and CD34 positivity in MyAg⁺ was higher than that in MyAg⁻ ALL types, but no differences were found with regard to other clinical features.

A Ru diphosphonato complex with a metal-metal bond for water oxidation.

Unlike [Ru2(µ-O2CCH3)4], the structurally analogous water-soluble RuII,III2 diphosphonato complex K3[Ru2(hedp)2(H2O)2] (K3·1) is only involved in stoichiometric water oxidation with a maximum 67% O2 yield under CAN/HNO3 solution (pH 1.0) for 2.5 h. The water oxidation mechanism and intermediate products were ascertained by UV-vis, ESI-MS and DFT calculation.

The studies on the correlation for gene expression of tyrosine-kinase receptors and vascular endothelial growth factor in human neuroblastomas.

OBJECTIVE: To study the correlation and clinical significance of expression of tyrosine-kinase receptors (TrkA and TrkB) and vascular endothelial growth factor (VEGF) in human neuroblastomas. METHODS: Expression of TrkA, TrkB, and VEGF mRNA was semi-quantitatively detected by reverse transcription-polymerase chain reaction (RT-PCR) in 51 cases of neuroblastomas. RESULTS: The expression of TrkA was significantly higher in lower-stage group compared with higher-stage group (P<0.05), whereas the expression of VEGF was significantly higher in the higher-stage group compared with the lower-stage group (P<0.05). The expression of TrkA was correlated negatively with the expression of VEGF (P<0.01), and has remarkable dependability with 2-year cumulative survival rate (P<0.01). The expression of TrkA in the lower age group was significantly higher than in the higher age group of NB cases (P<0.01). TrkA has a good prognostic impact on neuroblastoma patients (P<0.01). The expression of TrkB was significantly higher in the higher-stage group compared with the lower-stage group (P<0.05) and was positively correlated with VEGF expression (r=0.342, P<0.05); their expression also has remarkable dependability with the 2-year cumulative survival rate (P<0.01). The expression of TrkB was significantly lower in the higher age group compared with the lower age group (P<0.05). The 2-year cumulative-survival rate in the lower age group had a great significance compared with the higher age group (P<0.001). TrkB has a bad prognostic impact on neuroblastoma patients (P<0.01). CONCLUSIONS: TrkA was highly expressed in good prognostic neuroblastomas; however, TrkB and VEGF were highly expressed in poor prognostic neuroblastomas. The expression of TrkA was negatively correlated with the expression of VEGF, whereas the expression of TrkB was positively correlated with the expression of VEGF. These 3 genes have an important clinical significance relating to the tumor stage and the outcome for patients with neuroblastomas.

[Role of caspase-8 in TRAIL-induced apoptosis of neuroblastoma cell lines].

OBJECTIVE: The aim of this study was to investigate whether the induction of caspase-8 by γ-interferon (IFNγ) renders neuroblastoma (NB) cells sensitive to tumor necrosis factor related apoptosis inducing ligand(TRAIL). METHODS: Caspase-8 mRNA expression was determined by RT-PCR. The effects of IFNγ, TRAIL, IFNγ +TRAIL and caspase-8 inhibitor+ TRAIL on the growth and apoptosis of NB cells were detected with the methods of reduction rate of Alamar Blue assay and flow cytometry. The relative caspase-8 activity was measured with colorimetric assay. RESULTS: Caspase-8 expression was detectable in CHP212 cells which were sensitive to TRAIL, with an increased expression after treatment with IFNγ. Caspase-8 was undetectable in SH-SY5Y(SY5Y) cells which were resistant to TRAIL, but an increased expression of caspase-8 mRNA was found after treatment with IFNγ. Moreover, TRAIL combined with IFNγ induced apoptosis in SY5Y cells. The relative caspase-8 activity of CHP212 cells increased with the prolonged TRAIL action time. The relative caspase-8 activity of SY5Y cells in the IFNγ+TRAIL group was significantly higher than those of the control, IFNγ, TRAIL and inhibitor groups. CONCLUSIONS: NB cells expressing caspase-8 are sensitive to TRAIL. TRAIL induces apoptosis in NB cells with an increase of relative caspase-8 activity.

Zinc complexes supported by pyridine-N-oxide ligands: synthesis, structures and catalytic Michael addition reactions.

New dipyridylpyrrole N-oxide ligands HL1 and HL2 are designed and synthesized via oxidation of 2-(5-(pyridin-2-yl)-1H-pyrrol-2-yl)pyridine (Hdpp) by using 3-chloroperbenzoic acid (m-CPBA) in CH2Cl2. The treatment of ZnEt2 with two equiv. of HL1 and HL2 affords [Zn(L1)2] and [Zn(L2)2] in medium yield, respectively. These ligands and zinc complexes are fully characterized by NMR, IR, UV-vis and ESI-MS spectroscopy and X-ray diffraction analysis. The structure of HL1 and HL2 shows a planar geometry. The intramolecular hydrogen-bond interactions between the imino hydrogen and N-oxide oxygen atom are observed. In [Zn(L1)2] and [Zn(L2)2], two ligands chelate to the zinc metal with a cross perpendicular geometry. The zinc complexes were employed as a highly efficient catalyst for the thiol-Michael addition of thiols to α,ß-unsaturated ketones in EtOH at room temperature. The loading of the catalyst is lowered to 0.01 mol%. The catalytic mechanism was proposed based on NMR and ESI-MS experiments.

Immunophenotypic, cytogenetic and clinical features of 192 AML patients in China.

Immunophenotypic characterization of the leukemic cells has been widely used as a tool for diagnosis, classification and prognosis of leukaemia. A total of 192 Chinese patients with acute myeloid leukemia (AML) were immunophenotyped by flow cytometry using a panel of monoclonal antibodies. Among the 192 patients enrolled in this study, 125 cases were also subjected to karyotype analysis by G-banding technology. We found that CD33, CD13, MPO and CD117 were the most commonly expressed antigens in AML. A combination of intensive autofluorescence, both CD34(-) and HLA-DR(-), and high expression of CD13, CD33 and MPO had significant value for M3 diagnosis. CD14 was expressed only in M4 and M5, and both intensive positivity of CD64 and CD15 with high expression of HLA-DR may suggest great possibility for diagnosis of M5. Lymphoid markers expression was documented in 47.9% of the 192 AML cases analyzed. CD56 (26.0%) and CD7 (20.8%) were the most commonly expressed lymphoid markers in AML patients. Abnormal karyotypes were detected in 76 out of 125 (60.8%). Higher CD34 positivity was found in LymAg(+) group (77.2%) than in LymAg(-) group (48.0%). Our results indicate that immunophenotype analysis was useful for AML diagnosis and classification and the immunophenotype did have relevance to the abnormal cytogenetic changes and clinical features in AML.

Role of caspase 8 as a determinant in trail sensitivity of neuroblastoma cell lines.

OBJECTIVE: Resistance of neuroblastoma (NB) cells to tumor necrosis factor-related apoptosis inducing ligand (TRAIL)-mediated apoptosis is thought to be caused by loss of caspase 8 expression. The aim of this study is to investigate if induction of caspase 8 by gamma-interferon (IFN gamma) renders NB cells sensitive to TRAIL. METHODS: Caspase 8 expression was monitored by RT-PCR and Western blot analysis. The effects of IFN gamma, TRAIL, IFN gamma + TRAIL, and caspase 8 inhibitor + TRAIL on the growth and apoptosis of NB cells were detected with the methods of reduction rate of Alamar blue assay and flow cytometry. The relative caspase 8 activity was measured with colorimetric assay. RESULTS: An increased expression of caspase 8 mRNA and protein was found after treatment with IFN gamma. IFN gamma in combination with TRAIL decreased proliferation of NB cell line SH-SY5Y cells. The killing effect of TRAIL on NB cells expressing caspase 8 was depressed by caspase 8 inhibitor. The relative caspase 8 activity of NB cells expressing caspase 8 increased with the prolongation of TRAIL action time. CONCLUSIONS: TRAIL induced apoptosis in NB cells expressing caspase 8.

Self-Supported Hierarchical IrO2@NiO Nanoflake Arrays as an Efficient and Durable Catalyst for Electrochemical Oxygen Evolution.

Although traditional IrO2 nanoparticles loaded on a carbon support (IrO2@C) have been taken as a benchmark catalyst for the oxygen evolution reaction (OER), their catalytic efficiency, operation stability, and IrO2 utilization are far from satisfactory due to the inferior powdery structure and inevitable corrosion of both IrO2 and C under the oxidizing potentials. Here, a rational design of a self-supported hierarchical nanocomposite, composed of IrO2@NiO nanoparticle-built porous nanoflake arrays vertically growing on nickel foam, is proposed, which is demonstrated as a versatile strategy to achieve improved OER activity, remarkable long-term stability, and significantly reduced loading of IrO2 (0.62 atom %). Impressively, the resultant catalyst drives a steady OER current density of 10 mA cm-2, requiring 278 mV overpotential in 1.0 M KOH electrolyte for 25 h and outmaneuvring commercial IrO2@C with much higher mass loading. Further electrochemical investigation and mechanism analysis disclose that the greatly improved electrocatalytic activity stems from the advantageous hierarchical structure and the synergistic effect between IrO2 and underlying potential-induced NiOOH, whereas the outstanding durability is attributed to the unique role of NiO in preventing IrO2 dissolution.

Enhanced effect of IFNgamma on the induced apoptosis of neuroblastoma cells by cytotoxic drugs.

The objective of this study was to explore the antitumor effects of cytotoxic drugs combined with IFNgamma on neuroblastoma cell line SH-SY5Y cells. The expression of caspase 8 mRNA and protein was detected with RT-PCR and Western blot analysis. The effects of cytotoxic drugs and IFNgamma combined with cytotoxic drugs on the growth and apoptosis of SH-SY5Y cells were detected with the methods of MTT and flow cytometry. Caspase 8 activity was measured by colorimetric assay. Caspase 8 was undetectable in SH-SY5Y cells with an increased expression of caspase 8 after the treatment of IFNgamma. SH-SY5Y cells were sensitive to Adriamycin relatively but resistant to TNFalpha and TRAIL, while IFNgamma-pretreated SH-SY5Y cells were more sensitive to the cytotoxic drugs with an increase of caspase 8 activity. The authors conclude that IFNgamma can sensitize SH-SY5Y cells to Adriamycin-, TNFalpha-, and TRAIL-induced apoptosis and this may be realized by the upregulation of caspase 8.

[Blocking TrkB-BDNF signal pathway decreases the livability of neuroblastoma cells].

OBJECTIVE: Brain-derived neurotrophic factor (BDNF) and its specific tryrosin kinase receptor-B (TrkB) are highly correlated to the chemoresistance of neuroblastoma (NB) cells and poor prognosis. This study observed the changes of the sensibility of NB cells to chemotherapy drug cisplatin (CDDP) before and after blockage of TrkB-BDNF signal pathway by specific tyrosin kinase inhibitor K252a. METHODS: Human NB cell line SH-SY5Y (SY5Y) was routinely cultured. Expression of TrkB was induced with nM all trans-retinoid acid (ATRA). Then BDNF, CDDP or K252a were added to the cultured SY5Y cells. Cell livability was assessed by methyl thiazolyl tetrazolium (MTT) assay. TrkB autophosphorylation was determined by Western blot analysis. Cell apoptosis rate was detected by flow cytometry (FCM). The conformation of apoptosis cells was observed by transmission electron microscopy (TEM). RESULTS: The livability and apoptosis rate in SY5Y cells treated with ATRA, BDNF and CDDP were not different from the blank control group. However, after K252a together with ATRA, BDNF and CDDP treatment, the sensibility of SY5Y cells to chemotherapy drug CDDP increased, the livability decreased and the apoptosis rate increased in SY5Y cells when compared with the blank control group (P <0.01). K252a treatment resulted in blockage of TrkB autophosphorylation. CONCLUSIONS: The blockage of TrkB-BDNF signal pathway by K252a use can increase sensibility of NB cells to chemotherapy and thus decrease the livability of NB cells.

Understanding the energy level matching relationships between semiconductor photocatalysts and organic pollutants for effective photocatalytic degradations.

In this work, representative semiconductors CdS, V2O5, WO3 and P25 (Degussa TiO2 consisting of 80 wt% anatase and 20 wt% rutile) were chosen as the photocatalysts, and the common phenol along with its derivatives (p-nitrophenol, p-chlorophenol and hydroquinone) were designated as the probe pollutants. The energy levels of the frontier molecular orbitals (EHOMO and ELUMO) of organics, and the valence band (VB) and conduction band (CB) energy levels (EVB and ECB) of photocatalysts were obtained through experiments and calculations. By correlating the photocatalytic activities of photocatalysts for the degradations of the organic pollutants under the irradiation of a 300 W xenon lamp with their above-mentioned energy levels, some new findings can be acquired. To be specific, the more positive EHOMO of an organic pollutant leads to its easier photodegradation by photocatalysts. Meanwhile, the more negative VB position for a photocatalyst results in the higher photocatalytic activities for the degradations of organic pollutants. Therefore, the matching correlation between the EHOMO of an organic pollutant and the EVB of a photocatalyst is of great importance to the efficiency of photocatalytic degradation.