Effect of robbing intensity on reproductive success of Symphytum officinale (Boraginaceae).

The intervention of nectar robbers in plant pollination systems will cause some pollinators to modify their foraging behavior to act as secondary robbers, consequently adopting a mixed foraging strategy. The influence of nectar robbing on pollinator behavior may be affected by spatio-temporal difference of robbing intensity, and consequently, may have different effects on the pollination of host plants. However, whether and how the nectar robbing might influence pollinators under different robbing intensity still needs further investigation. In this study, Symphytum officinale was used to detect the effect of nectar robbers on pollinators under different robbing intensity as well as their effects on plant reproductive success. Six robbing levels and three bumblebees with mixed foraging behaviors were used to evaluate the effect of different robbing intensity on pollinator behavior, visitation rate, flower longevity and pollen deposition. Our results indicated that the robbing rate increased gradually with the proportion of robbed flowers, but which did not affect the frequency of legitimate visits. The increase of robbing rate promoted the corolla abscission, and then enhanced the self-pollen deposition, but which had no significant effect on cross-pollen deposition. These results indicate that the overall fitness of S. officinale was improved by combined self and cross-pollination modes when visited by both pollinators and nectar robbers simultaneously. Although nectar robbing is not uncommon, its consequences for pollination in the interaction web have not been well studied. Our results emphasize the significance of indirect impacts in mediating the adaptive outcomes of species interactions.

Corolla Abscission Triggered by Nectar Robbers Positively Affects Reproduction by Enhancing Self-Pollination in Symphytum officinale (Boraginaceae).

Nectar robbers, which affect plant fitness (directly or indirectly) in different degrees and in different ways, potentially constitute a significant part of mutualistic relationships. While the negative effects of nectar robbing on plant reproductive success have been widely reported, the positive effects remain unknown. The target of our study was to evaluate the effects of nectar robbers on the reproductive success of Symphytum officinale (Boraginaceae). We observed the behavior, species and times of visitors in the field, and we assessed the effect of nectar robbers on corolla abscission rate and time. To test the fitness of corolla abscission, we detected the changes in stigma receptivity, pollen viability, pollen amount and appendage opening size along with the time of flower blossom. The flowering dynamics and floral structure were observed to reveal the mechanism of self-pollination. Finally, pollen deposition seed set rate and fruit set rate were determined to estimate the effect of nectar robbers on reproduction success. We observed 14 species of visitors and 2539 visits in 50 h of observation; 91.7% of them were nectar robbers. The pressure and nectar removal of nectar robbers significantly promoted corolla abscission during a period when pollen grains are viable and the stigma is receptive. In addition, corolla abscission significantly increased the pollen deposition and seed setting rate. Our results demonstrate that nectar robbing contributes to enhancing seed production and positively and indirectly impacts the reproductive success of S. officinale. This mechanism involved the movement of anthers and indirect participation by nectar robbers, which was rarely investigated. Considering the multiple consequences of nectar robbing, understanding the impact of nectar robbers on plant reproduction is essential to comprehend the evolutionary importance of relationships between plants and their visitors.

CXCL12-CXCR4 promotes proliferation and invasion of pancreatic cancer cells.

OBJECTIVE: CXCL12 exerts a wide variety of chemotactic effects on cells. Evidence indicates that CXCL12, in conjunction with its receptor, CXCR4, promotes invasion and metastasis of tumor cells. Our objective was to explore whether the CXCL12-CXCR4 biological axis might influence biological behavior of pancreatic cancer cells. METHODS: Miapaca-2 human pancreatic cancer cells were cultured under three different conditions: normal medium (control), medium + recombinant CXCL12 (CXCL12 group), or medium + CXCR4-inhibitor AMD3100 (AMD3100 group). RT-PCR was applied to detect mRNA expression levels of CXCL12, CXCR4, matrix metalloproteinase 2 (MMP-2), MMP-9, and human urokinase plasminogen activator (uPA). Additionally, cell proliferation and invasion were performed using CCK-8 colorimetry and transwell invasion assays, respectively. RESULTS: CXCL12 was not expressed in Miapaca-2 cells, but CXCR4 was detected, indicating that these cells are capable of receiving signals from CXCL12. Expression of extracellular matrix-degrading enzymes MMP-2, MMP- 9, and uPA was upregulated in cells exposed to exogenous CXCL12 (P<0.05). Additionally, both proliferation and invasion of pancreatic cancer cells were enhanced in the presence of exogenous CXCL12, but AMD3100 intervention effectively inhibited these processes (P<0.05). CONCLUSIONS: The CXCL12-CXCR4 biological axis plays an important role in promoting proliferation and invasion of pancreatic cancer cells.

A facile titanium glycolate precursor route to mesoporous Au/Li4Ti5O12 spheres for high-rate lithium-ion batteries.

A facile, green strategy is explored to synthesize mesoporous Au/Li(4)Ti(5)O(12) spheres based on in situ conversion of titanium glycolate in LiOH aqueous solution. Compared with TiO(2) precursors, titanium glycolate possesses some strengths: (i) fast and easy preparation; (ii) direct reaction with LiOH without introduce of TiO(2) impurity. In the synthesis, the produced chemical waste is only the mixed solvent of acetone and ethylene glycol (EG). Furthermore, acetone and EG in chemical waste can be easily separated by distillation and reused in the next synthesis process due to the great difference between their boiling points. In particular, the as-prepared mesoporous Au/Li(4)Ti(5)O(12) spheres combines the advantages of large specific surface area (166 m(2)/g) and good electronic conduction enhanced by Au nanoparticles when used as an anode electrode material. The electrochemical tests show that the mesoporous Au/Li(4)Ti(5)O(12) spheres display excellent high rate capability and cycling performance.

Topochemical synthesis of cobalt oxide-based porous nanostructures for high-performance lithium-ion batteries.

Two kinds of topochemical conversion routes from cobalt hydroxide precursors to cobalt oxide-based porous nanostructures are presented: pyrolysis in air and hydrothermal treatment by the Kirkendall diffusion effect. These cobalt hydroxide precursors were synthesized by a simple hydrothermal approach with sodium acetate as mineralizer at 200 °C. Detailed proof indicates that the process of cobalt hydroxide precursor growth is dominated by a nucleation, dissolution, renucleation, growth, and exfoliation mechanism. By the topochemical conversion processes several Co(3)O(4) nanostructures, such as cobalt oxide-coated cobalt hydroxide carbonate nanowires, cobalt oxide nanotubes, hollow cobalt oxide spheres, and porous cobalt oxide nanowires, have been synthesized. The obtained Co(3)O(4) nanostructures have also been evaluated as the anode materials in lithium-ion batteries. It was found that the as-prepared Co(3)O(4) nanostructures exhibited high reversible capacity and good cycle performance due to their porous structure and small size.

[Clinical features and prognosis of solid-pseudopapillary tumor of the pancreas].

OBJECTIVE: To study the clinicopathological and immunohistochemical features, histogenesis and biological behavior, clinical treatment and prognosis of solid pseudopapillary tumor of the pancreas (SPT). METHODS: Routine HE and immunohistochemical (SP) stainings were used in the pathological examination of 18 cases of SPT. Their clinical data were retrospectively analyzed. All the 18 postoperative patients were followed-up for 3 months to 10 years with an average of 29.2 months. RESULTS: There were 16 females and 2 males, age ranging from 9 to 65 years with mean age of 25.3 years. Abdominal pain and palpable mass were among the major complains. Tumors were encapsulated and mixed with solid and cystic tissues. Histological features were pseudopapillary structure with a fibrovascular core. Immunhistologically, most tumors were positive for alpha-AT, alpha-ACT and Vim, with a high percentage of 94.4%. The eighteen cases were followed-up from 3 to 120 months. Five cases received reoperation after recurrence, and 14 cases were alive. Maximum survival time was 121 months and the minimum survival time was 3 months, with a median survival time of 23.0 months. The 5-year survival rate was 72.2%. A Kaplan-Meier analysis revealed that patient's age, tumor size, pathologic features, metastasis were major prognostic factors for SPT. CONCLUSION: SPT is a tumor of low-grade malignancy and may be derived from multipotent stem cells. SPT most frequently affects young female, and has distinct clinicopathologic manifestation with excellent prognosis after surgical treatment.

Synthesis, self-assembly, disassembly, and reassembly of two types of Cu2O nanocrystals unifaceted with {001} or {110} planes.

In this work, we describe a solution-based synthesis of monodisperse Cu(2)O nanocrystals with controllable sizes in the nanoscale regime. Two types of nanocrystals, cubes and rhombic dodecahedra unifaceted with either {001} or {110} crystal planes, have been prepared at a 100% morphological yield. In particular, synthetic parameters and formation processes of the Cu(2)O nanocrystals have been investigated in detail, and a range of well-oriented supercrystals/superlattices built from the two types of nanobuilding blocks have been attained for the first time. It has been revealed that n-hexadecylamine used in the present work plays multiple roles: it serves as a chelating ligand to form [Cu(NH(2)C(16)H(33))(4)](2+) complex precursor, as a phase-transferring agent to transfer divalent Cu(2+) ions into the organic phase, as a reducing agent to generate monovalent Cu(+) (i.e., Cu(2)O), as a passivating adsorbate to control crystal morphology, and as a surface capping agent to generate self-assemblies of nanocrystals via van der Waals interaction. Apart from synthesis and self-assembly, disassembly and reassembly of Cu(2)O nanocrystals have also been investigated. The disassembly processes are accompanied with aggregative growths of nanocrystals, which can be attributed to a combined process of "oriented attachment" and Ostwald ripening, leading to permanent engagement and enlargement of nanocrystals. Finally, our self-assembled nanocrystals of Cu(2)O show a lower detection limit, lower operating temperature, and higher sensitivity in ethanol vapor detection, compared with other Cu(2)O-based alcohol sensors reported in the recent literature. A greater depletion layer of carrier and a relatively small contact potential may account for the observed sensing enhancement in the sensors made from the organized Cu(2)O nanocrystals.

Abnormal gas sensing characteristics arising from catalyzed morphological changes of ionsorbed oxygen.

Abnormal gas sensing characteristics are observed at low temperature in uniformly loaded Pt@SnO(2) nanorod gas sensors. The sensors operated at 200 degrees C exhibit opposite variations of resistances, and the change of resistance decreases with increasing ethanol concentration. In contrast, the sensors operated at 300 degrees C show regular behavior and the sensitivity is extremely high. Such behaviors are ascribed to Pt-catalyzed morphological changes of ionsorbed oxygen at low temperature. The present results are the bases for further investigating the effect of ionsorbed oxygen morphologies on gas sensing.

SnO2 monolayer porous hollow spheres as a gas sensor.

The authors report on gas sensing properties of SnO2 hollow spheres with diverse microstructures, which are synthesized through controlled precipitation of Sn(OH)4 layers on carbon sphere templates, followed by heat treatment at different temperatures. Hollow spheres derived at 973 K consist of monolayer SnO2 grains, which lead to a huge activated surface area. The sensitivity of sensors based on SnO2 monolayer hollow spheres is up to 51 at 100 ppm ethanol, which is much higher than that of two other samples. We attribute this enhancement mostly to the enhanced depletion effect arising from the increased exposed surface. Our results suggest a direction for improving the performance of gas sensors by using monolayer porous hollow spheres.

Prostate specific antigen detection using microgapped electrode array immunosensor with enzymatic silver deposition.

BACKGROUND: Analysis of trace proteins plays an essential role in the fields of biomedical research and clinical diagnosis. Development of methods for the detection of proteins at very low concentrations has historically been a challenge in immunochemistry. We have developed an electrical immunosensor for the detection of prostate specific antigen (PSA). METHODS: The electrical immunosensor uses a microgapped interdigitated electrode array (MGIDEA) based on enzymatic silver deposition reaction. The deposition of silver was dispersed over the microgaps and allows the microgapped interdigitated electrodes to be electrically connected, resulting in an increase in electrical conductance of MGIDEA that is used to quantify the analyte concentration. We used this electrical immunosensor to measure PSA in human serum samples from patients with prostate diseases. RESULTS: This electrical immunosensor exhibited a linear response with PSA concentrations over a 6-decade range from 1.0 pg/L to 1.0 microg/L, with detection limit of 0.9 pg/L. PSA concentrations using this immunosensor agreed within 10% of those obtained using a commercial chemiluminescent immunoassay. CONCLUSIONS: The MGIDEA method has characteristics (analyte specific, low background, low limit of detection) that provide potential for molecular detection in various biomedical areas.

[Differentiated thyroid carcinoma in children and adolescents: clinical characteristics and treatment].

OBJECTIVE: To explore the clinicopathologic characteristics, treatment and prognosis of differentiated thyroid carcinoma (DTC) in adolescents. METHODS: The data of 46 patients with DTC under the age of 18 years were retrospectively reviewed. RESULTS: Twenty patients were misdiagnosed in this group (43.5%). All patients received operation, including 39 unilateral neck dissection and 6 bilateral neck dissection, followed by postoperative thyrotropin suppressive therapy. There were 42 cases of papillary carcinoma (91.3%) and 4 cases of follicular carcinoma (8.7%). Cervical lymph node metastasis was found in 39 cases (84.8%). In the follow-up period of 1 to 25 years (mean 10 years), no death of thyroid carcinoma occurred. CONCLUSIONS: The most common DTC in adolescents is papillary carcinoma with better prognosis regardless of the higher incidence of cervical lymph node metastasis. The optimal extent of primary thyroidectomy and neck dissection followed by postoperative thyrotropin suppressive therapy in adolescents with DTC may improve the quality of life and decrease the incidence of complications.