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Reactive oxygen species (ROS) play very important roles in the photocatalytic reactions of semiconductors. Using a continuous flow chemiluminescence (CFCL) system, we developed three methods for the selective, sensitive, and online detection of O2(• -), •OH, and H2O2 generated during ultraviolet (UV) irradiation of nano-TiO2 suspensions. TiO2 nanoparticles were irradiated in a photoreactor and pumped continuously into a detection cell. To detect O2(• -), luminol was mixed with TiO2 before it entered the detection cell. For the detection of short-lived •OH, phthalhydrazide was added into the photoreactor to capture •OH, and then mixed with H2O2/K5Cu(HIO6)2 to produce chemiluminescence (CL). To detect H2O2, an irradiated TiO2 suspension was kept in darkness for 30 min, and then mixed with luminol/K3Fe(CN)6 to produce CL. The selectivity of each method for a particular ROS was verified by using specific ROS scavengers. For a given ROS, a comparison between CL and conventional method showed good agreement for a series of TiO2 concentrations. The sensitivity of CL method was approximately 3-, 1200-, and 5-fold higher than the conventional method for O2(• -), •OH, and H2O2, respectively. To demonstrate the utility of the methods, ROS in three different types of TiO2 suspensions was detected by CFCL. It was found that photodegradation efficiency of Rhodamine B correlated the best (R(2)0.95) with the amount of photogenerated •OH, implying that •OH was the major oxidant in Rhodamine B photodegradation reaction. CFCL may provide a convenient tool for the studies on the reaction kinetics of ROS-participated decomposition of environmental contaminants.

By using minimax methods in critical point theory, we obtain the existence of periodic solutions for second-order ordinary differential equations with linear nonlinearity.

G. Gratzer, H. Lakser, and E. T. Schmidt proved that every finite distributive lattice D with n join-irreducible elements can be represented as the congruence lattice of a lattice L with O(n2) elements. G. Gratzer, I. Rival, and N. Zaguia gave knα, α < 2, as a lower bound for the size of such a lattice L; a sharper form, 1/64(n/log2n)2, of this result was given by Y. Zhang. In this note, we apply a recent result of R. Freese, to obtain 1/16 n2/log2n as a lower bound. We also give a direct proof of Freese's result.

To investigate the influence of different transplantation times on the survival and immigration of the bone marrow mesenchymal stem cells (BMSCs) in injured spinal cord by subarachnoid administration, and to evaluate the most optimal subarachnoid administration times for BMSCs.Eight adult male rats (weighing 120 g) were used to isolate BMSCs that were cultured, purified and labeled with Hoechst 33342 in vitro. Another 75 adult Wistar rats (weighing 220 g) were made the spinal cord injury (SCI) models at T9,10 level according to the improved Allen's method and were randomly divided into 5 groups (groups A, B, C, D, and E, n=15). The labeled BMSCs at 1 x 10(7)/mL 0.1 mL were injected into subarachnoid space of the rats via a catheters under the subarachnoid space in groups A (one time at 1 week), B ( two times at 1 and 3 weeks), C (3 times at 1, 3, and 5 weeks) and D (5 times at 1, 3, 5, 7, and 9 weeks) and 0.2 mL phosphate-buffered saline (PBS) was injected in group E (5 times at 1, 3, 5, 7, and 9 weeks) as blank control. The neurological functions were evaluated using the Basso-Beattie-Bresnahan (BBB) scale 1, 3, 5, 7, 9, and 12 weeks after transplantation. The migration, survival, differentiation, and histomorphological changes of BMSCs were observed by HE, immunohistochemistry, and fluorescence microscopy.At 3 weeks after injury, there were significant differences in the BBB scores between group E and groups A, B, C, D (P0.01), and between groups A, B and groups C, D (P0.01). At 7, 9, and 12 weeks, the BBB scores were significantly higher in groups C and D than in groups A and B (P0.01), and in group B than in group A (P0.01). There were no significant differences in the BBB scores between groups C and D (P0.05). The fluorescence microscopy showed that the transplanted BMSCs survived and grew in the injured region at 3 weeks after injury and as time went on, the transplanted cells gradually decreased in group A; in groups B, C, and D, BMSCs count reached the peak values at 5 and 7 weeks and then gradually decreased. At 12 weeks, the survival BMSCs were significantly more in groups C and D than in groups A and B (P0.01). HE staining showed that the formation of cavity was observed in each group at 3 weeks after injury and the area of cavity gradually decreased in groups A, B, C, and D. At 12 weeks, the area of cavity was the maximal in groups C and D, moderate in groups A and B, and the maximal in group E. The immunohistochemistry staining indicated that the expression of NF-200 was more intense in groups C and D than in groups A and B. The expression of NF-200-positive fibers was more intense in group C.Multiple administration of BMSCs promotes the restoration of injured spinal cord and improves neurological functions, and three times for BMSCs transplantation is best.

To investigate tissue engineered spinal cord which was constructed of bone marrow mesenchymal stem cells (BMSCs) seeded on the chitosan-alginate scaffolds bridging the both stumps of hemi-transection spinal cord injury (SCI) in rats to repair the acute SCI.BMSCs were separated and cultured from adult male SD rat. Chitosan-alginate scaffold was produced via freeze drying, of which the structure was observed by scanning electron microscope (SEM) and the toxicity was determined through leaching liquor test. Tissue engineered spinal cord was constructed by seeding second passage BMSCs on the chitosan-alginate scaffolds (1 x 10(6)/mL) in vitro and its biocompatibility was observed under SEM at 1, 3, and 5 days. Moreover, 40 adult female SD rats were made SCI models by hemi-transecting at T9 level, and were randomly divided into 4 groups (each group, n=10). Tissue engineered spinal cord or chitosan-alginate scaffolds or BMSCs were implanted in groups A, B, and C, respectively. Group D was blank control whose spinal dura mater was sutured directly. After 1, 2, 4, and 6 weeks of surgery, the functional recovery of the hindlimbs was evaluated by the Basso-Beattie-Bresnahan (BBB) locomotor rating score. Other indexes were tested by wheat germ agglutinin-horseradish peroxidase (WGA-HRP) retrograde tracing, HE staining and immunofluorescence staining after 6 weeks of surgery.Chitosan-alginate scaffold showed three-dimensional porous sponge structure under SEM. The cells adhered to and grew on the surface of scaffold, arranging in a directional manner after 3 days of co-culture. The cytotoxicity of chitosan-alginate scaffold was in grade 0-1. At 2, 4, and 6 weeks after operation, the BBB score was higher in group A than in other groups and was lower in group D than in other groups; showing significant differences (P0.05). At 4 and 6 weeks, the BBB score was higher in group B than in group C (P0.05). After 6 weeks of operation, WGA-HRP retrograde tracing indicated that there was no regenerated nerve fiber through the both stumps of SCI in each group. HE and immunofluorescence staining revealed that host spinal cord and tissue engineering spinal cord linked much compactly, no scar tissue grew, and a large number of neurofilament 200 (NF-200) positive fibers and neuron specific enolase (NSE) positive cells were detected in the lesioned area in group A. In group B, a small quantity of scar tissue intruded into non-degradative chitosan-alginate scaffold at the lesion area edge, and a few of NSE fluorescence or NF-200 fluorescence was observed at the junctional zone. The both stumps of SCI in group C or group D were filled with a large number of scar tissue, and NSE positive cells or NF-200 positive cells were not detected. Otherwise, there were obviously porosis at the SCI of group D.The tissue engineered spinal cord constructed by multi-channel chitosan-alginate bioscaffolds and BMSCs would repair the acute SCI of rat. It would be widely applied as the matrix material in the future.

To study the immunophenotypic features of primary nasal non-Hodgkin's lymphoma (NHL) and its association with Epstin-Barr virus (EBV) infection.Twenty-nine cases of nasal non-Hodgkin's lymphoma were studied. CD45RO, CD3epsilon, CD56, CD20, TIA-1 and granzyme B were detected by immunohistochemistry staining for investigate immunophenotype. The expression of EBV-latent membrane protein (LMP-1) were detected by immunohistochemistry. EBV-encoded RNA (EBER1/2) were detected by in situ hybridization (ISH).Among the 29 cases, CD45RO was positive in all the 29 cases (100. 00%), CD3epsilon and TIA-1 and granzyme B were positive in 19 cases (65.52%), CD56 was positive in 17 cases (58.62%), while CD20 negative in all the 29 cases (100.00%). The positive expression rates of EBER1/2 and LMP-1 were 79.31% and 48.28%. The positive expression rates of EBER1/2 and LMP-1 were not significantly different between peripheral T cell lymphomas and NK/T cell lymphomas( P0.05).Most nasal NHL cases are NK/T cell lymphomas. Nasal NHL is strong associated with EBV infection, but EBV infection is not associated with immunophenotype. EBV infection may play a role in the pathogenesis of the nasal non-Hodgkin's lymphoma.

Endogenous variables in structural models of agricultural commodity markets are typically treated as stationary. Yet, tests for unit roots have rather frequently implied that commodity prices are not stationary. This seeming inconsistency is investigated by focusing on alternative specifications of unit root tests. We apply various specifications to Illinois farm prices of corn, soybeans, barrows and gilts, and milk for the 1960 through 2002 time span. The preponderance of the evidence suggests that nominal prices do not have unit roots, but under certain specifications, the null hypothesis of a unit root cannot be rejected, particularly when the logarithms of prices are used. If the test specification does not account for a structural change that shifts the mean of the variable, the results are biased toward concluding that a unit root exists. In general, the evidence does not favor the existence of unit roots.

We report the surprising chemiluminescence (CL) behavior of fluorescent carbon dots in the presence of a strong alkaline solution, such as NaOH or KOH. The CL intensity was dependent on the concentration of the base and carbon dots in a certain range. A possible CL mechanism was studied by UV-Vis, fluorescence, CL, FTIR, XPS and EPR spectroscopy. Radiative recombination of the injected electrons by "chemical reduction" of carbon dots with thermally excited generated holes was proposed, which sheds new light on the characteristics of carbon dots.

In the title compound, [Mn(C(10)H(7)N(2)O(2))(2)(H(2)O)(4)], the Mn(II) atom, lying on an inversion center, has an octa-hedral environment with four coordinated water mol-ecules in the equatorial plane and two N atoms from two 4-(imidazol-1-yl)benzoate ligands at the axial sites. The complex mol-ecules are connected into a three-dimensional network by extensive hydrogen bonds between the water mol-ecules and the carboxyl-ate O atoms.