Three-dimensional culture and clinical drug responses of a highly metastatic human ovarian cancer HO-8910PM cells in nanofibrous microenvironments of three hydrogel biomaterials.

BACKGROUND: Ovarian cancer is a highly aggressive malignant disease in gynecologic cancer. It is an urgent task to develop three-dimensional (3D) cell models in vitro and dissect the cell progression-related drug resistance mechanisms in vivo. In the present study, RADA16-I peptide has the reticulated nanofiber scaffold networks in hydrogel, which is utilized to develop robust 3D cell culture of a high metastatic human ovarian cancer HO-8910PM cell line accompanied with the counterparts of Matrigel and collagen I. RESULTS: Consequently, HO-8910PM cells were successfully cultivated in three types of hydrogel biomaterials, such as RADA16-I hydrogel, Matrigel, and collagen I, according to 3D cell culture protocols. Designer RADA16-I peptide had well-defined nanofiber networks architecture in hydrogel, which provided nanofiber cell microenvironments analogous to Matrigel and collagen I. 3D-cultured HO-8910PM cells in RADA16-I hydrogel, Matrigel, and collagen I showed viable cell proliferation, proper cell growth, and diverse cell shapes in morphology at the desired time points. For a long 3D cell culture period, HO-8910PM cells showed distinct cell aggregate growth patterns in RADA16-I hydrogel, Matrigel, and collagen I, such as cell aggregates, cell colonies, cell clusters, cell strips, and multicellular tumor spheroids (MCTS). The cell distribution and alignment were described vigorously. Moreover, the molecular expression of integrin ß1, E-cadherin and N-cadherin were quantitatively analyzed in 3D-cultured MCTS of HO-8910PM cells by immunohistochemistry and western blotting assays. The chemosensitivity assay for clinical drug responses in 3D context indicated that HO-8910PM cells in three types of hydrogels showed significantly higher chemoresistance to cisplatin and paclitaxel compared to 2D flat cell culture, including IC50 values and inhibition rates. CONCLUSION: Based on these results, RADA16-I hydrogel is a highly competent, high-profile, and proactive nanofiber scaffold to maintain viable cell proliferation and high cell vitality in 3D cell models, which may be particularly utilized to develop useful clinical drug screening platform in vitro.

Thin-layer chromatography combined with surface-enhanced Raman scattering for rapid detection of benzidine and 4-aminobiphenyl in migration from food contact materials based on gold nanoparticle doped metal-organic framework.

In this work, a rapid and sensitive thin-layer chromatography combined with surface-enhanced Raman spectroscopy method was established for rapid detection of benzidine and 4-aminobiphenyl in migration from food contact materials based on Au nanoparticle doped metal-organic framework. Benzidine and 4-aminobiphenyl were firstly separated by thin-layer chromatography to solve the limitation of their overlapping Raman peaks. Then the target molecules were monitored by adding AuNPs/MIL-101(Cr) on the sample spots. Under the optimum conditions, the concentration of benzidine and 4-aminobiphenyl can be quantitatively measured in the range of 2.0-20.0 and1.0-15.0 µg/L, respectively with good linear relationship, and the limits of detection were 0.21 and 0.23 µg/L, respectively. Furthermore, the developed method was applied to analyze benzidine and 4-aminobiphenyl in migration of different food contact materials. The recoveries of benzidine and 4-aminobiphenyl for migration of food contact materials, including paper cups, polypropylene food containers, and polyethylene glycol terephthalate bottles, were 80.6-116.0 and 80.7-118% with relative standard deviations of 1.1-9.1 and 3.1-9.9%, respectively. Surface-enhanced Raman scattering detection was performed conveniently in the on-plate mode without additional elution process. The method shows great potential in rapid monitoring of hazardous substances with overlapping characteristic Raman peaks in food contact materials.

Synthesis of a Highly Stable Pd@CeO2 Catalyst for Methane Combustion with the Synergistic Effect of Urea and Citric Acid.

Making use of synergy between urea and citric acid, a core-shell Pd@CeO2 catalyst with spherical morphology was facilely synthesized by a hydrothermal method. The formation mechanism of the core-shell structure in the presence of citric acid and hydrogen peroxide was studied. Results showed that the Pd@CeO2 catalyst exhibited high catalytic activity in methane oxidation. Pd nanoparticles were well stabilized by CeO2 shell encapsulation, resulting in high stability of the catalyst. A high CH4 conversion of 99% was retained after 50 h on-stream reaction at 500 °C. Additionally, many tiny pores on the CeO2 shell surface were beneficial for the full contact between reactants and active components. Pd nanoparticles were highly dispersed inside the shell, improving the utilization efficiency of active components. The results also demonstrated that the Pd species in the catalyst existed in the form of oxidation state, mainly in PdO (ca. 66.6%), which played an essential part in methane combustion.

Effects of A-site non-stoichiometry in YxInO3+δ on the catalytic performance during methane combustion.

A novel non-stoichiometric YxInO3+δ (YIO-x, 0.8 ≤ x ≤ 1.04) perovskite catalyst with a large number of oxygen vacancies and high specific surface area was synthesized using glycine self-propagating gel combustion. It was found that low levels of non-stoichiometry in the A site of YxInO3+δ effectively increased the amount of oxygen desorption by 39-42% when compared to the original (YIO-1) due to Y-deficiency and oxygen vacancies. Further investigations showed that the non-stoichiometry also brings a significant change to the Lewis acid sites on the surface of the sample, which confirmed to be a great promoter for the catalytic combustion of methane. In addition, the catalytic performance increased with the increasing intensity of acid sites. After 50 h of the stability test, the catalysts maintained high activity, indicating their good catalytic stability.

A Novel Highly Sensitive NO2 Sensor Based on Perovskite Na0.5+xBi0.5TiO3-δ Electrolyte.

NOx is one of dangerous air pollutants, and the demands for reliable sensors to detect NOx are extremely urgent recently. Conventional fluorite-phase YSZ used for NOx sensor requires higher operating temperature to obtain desirable oxygen ion conductivity. In this work, perovskite-phase Na0.5Bi0.5TiO3 (NBT) oxygen conductor was chosen as the solid electrolyte to fabricate a novel highly sensitive NO2 sensor with CuO as the sensing electrode and Pt as reference electrode. Na dopped Na0.5Bi0.5TiO3 greatly improved the sensing performance of this sensor. The optimal sensor based on Na0.51Bi0.50TiO3-δ exhibited good response-recovery characteristics to NO2 and the response current values were almost linear to NO2 concentrations in the range of 50-500 ppm at 400-600 °C. The response current value towards NO2 reached maximum 11.23 µA at 575 °C and the value on NO2 is much higher than other gases (CH4, C2H4, C3H6, C3H8, CO), indicating good selectivity for detecting NO2. The response signals of the sensor were slightly affected by coexistent O2 varying from 2 to 21 vol% at 575 °C. The response current value decreased only 4.9% over 2 months, exhibiting the potential application in motor vehicles.

Alkaline-Earth Metals-Doped Pyrochlore Gd2Zr2O7 as Oxygen Conductors for Improved NO2 Sensing Performance.

This work proposed a novel strategy to fabricate highly-stable NO2 sensor based on a pyrochlore-phase Gd2Zr2O7 oxygen conductor. The incorporation of alkaline-earth metals distinctly enhances the sensing performance of the Gd2Zr2O7 based sensors. The excellent sensor based on Gd1.95Ca0.05Zr2O7+δ exhibits rapid response-recovery characteristics with the maximum response current value (ΔI = 6.4 µA), extremely short 90% responce (3 s) and 90% recovery (35 s) time towards 500 ppm NO2 at 500 °C, which is better than that of commercial YSZ under the same condition. The ΔI value towards NO2 is much higher than those towards other gases (CH4, C3H6, C3H8, CO, NO, SO2, C2H4, CO2 and C2H6), exhibiting excellent selectivity for detecting NO2. The response signal basically maintains a stable value of 6.4 µA after the sensors was stored for half a month and a month. The outstanding selectivity and highly stability of the NO 2 sensors based on Gd2-xMxZr2O7+δ are expected to a promising application in automotive vehicles.

A GdAlO3 Perovskite Oxide Electrolyte-Based NOx Solid-State Sensor.

NOx is a notorious emission from motor vehicles and chemical factories as the precursor of acid rain and photochemical smog. Although zirconia-based NOx sensors have been developed and showed high sensitivity and selectivity at a high temperature of above 800 °C, they fail to show good performance, and even don't work at the typical work temperature window of the automotive engine (<500 °C). It still is a formidable challenge for development of mild-temperature NOx detector or sensor. Herein, a novel amperometric solid-state NOx sensor was developed using perovskite-type oxide Gd1-xCaxAlO3-δ(GCA) as the electrolyte and NiO as the sensing electrode. NOx sensing properties of the device were investigated at the temperature region of 400-500 °C. The response current value at -300 mV was almost linearly proportional to the NOx concentration between 300 and 500 ppm at 500 °C. At such a temperature, the optimal sensor gave the highest NO2 sensitivity of 20.15 nA/ppm, and the maximum response current value reached 5.57 µA. Furthermore, a 90% response and 90% recover time to 500 ppm NO2 were about 119 and 92 s, respectively. The excellent selectivity and stability towards NOx sensing showed the potential application of the sensor in motor vehicles.

Overfeeding during a critical postnatal period exacerbates hypothalamic-pituitary-adrenal axis responses to immune challenge: a role for adrenal melanocortin 2 receptors.

Early life diet can critically program hypothalamic-pituitary-adrenal (HPA) axis function. We have previously shown rats that are overfed as neonates have exacerbated pro-inflammatory responses to immune challenge with lipopolysaccharide (LPS), in part by altering HPA axis responses, but how this occurs is unknown. Here we examined neonatal overfeeding-induced changes in gene expression in each step of the HPA axis. We saw no differences in glucocorticoid or mineralocorticoid receptor expression in key regions responsible for glucocorticoid negative feedback to the brain and no differences in expression of key HPA axis regulatory genes in the paraventricular nucleus of the hypothalamus or pituitary. On the other hand, expression of the adrenal melanocortin 2 receptor (MC2R) is elevated after LPS in control rats, but significantly less so in the neonatally overfed. The in vitro adrenal response to ACTH is also dampened in these rats, while the in vivo response to ACTH does not resolve as efficiently as it does in controls. These data suggest neonatal diet affects the efficiency of the adrenally-mediated response to LPS, potentially influencing how neonatally overfed rats combat bacterial infection.

Synthesis of La-Co-O Mixed Oxides via Polyethylene Glycol-Assisted Co-Precipitation Method for Total Oxidation of Benzene.

La-Co-O mixed oxides (LCO) were prepared by co-precipitation method with the presence of polyethylene glycol (PEG) as dispersant. The influence of adding different molecular weight of PEG (0, 2 000, 6 000, 20 000 g·mol-1) on the physicochemical and catalytic properties of La-Co-O mixed oxides for total oxidation of benzene was investigated. The samples were characterized by means of N2 physical adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed reduction by H2 (H2-TPR), temperature-programmed desorption of O2 (O2-TPD), and X-ray photoelectron spectroscopy (XPS). The order of catalytic activity was found to be LCO-PEG6000>LCO>LCO-PG20000>LCO-PG2000. Particularly, LCO-PEG6000 exhibited benzene conversion of 99% at temperature as low as 383 ℃, which was 126 ℃ lower than that of LCO. The characterization result reveals that all samples had a BET surface area of about 9～10 m2·g-1. The XRD result shows that on all samples LaCoO3 perovskite was mainly formed together with a small amount of La2O3 and Co3O4. The addition of PEG was favorable for the formation of LaCoO3 perovskite. Particularly, the addition of PEG-6000 effectively suppressed the agglomeration of LaCoO3 perovskite, giving rise to small and uniform particles as observed by SEM. Moreover, the results of H2-TPR and O2-TPD indicate that the obtained La-Co-O mixed oxides showed higher reducibility and lattice oxygen mobility, and the Co 2p XPS analysis suggests that more surface Co3+ active species were presented by the addition of PEG-6000. These properties are thought to contribute to the high activity in benzene total oxidation.

The effects of self-assembling peptide RADA16 hydrogel on malignant phenotype of human hepatocellular carcinoma cell.

The aim of this study will provide a self-assembling peptide (RADA16-I) -derived hydrogel as a tool for investigation the malignant phenotype of human hepatocellular carcinoma cell. Characteristic analysis indicated that the peptide consists of a well-defined secondary structure and self-assembly property. Our results showed that these cells cultured in RADA16-I hydrogels showed a spindle-shaped phenotype with irregular and radial nuclei. Immunohistochemical results showed that the expression of fibronectin in hepatocellular carcinoma cells is positive cultured in RADA16-I hydrogels, and the expression levels of laminin are weakly positive. DNA contents cultured in RADA16-I hydrogel gradually increased up to Day 9. The expression levels of VEGFA, EGF and FGF2 in three hydrogels showed no statistically significant differences (P > 0.05), and the expression levels of IGF-1 in RADA16-I and collagen-I were significantly lower than those of in the Matrigel hydrogel (P ≤ 0.05). These findings suggested that the RADA16-I will help to provide a better physiological substrate for hepatocellular carcinoma cell culture, may serve as an ideal model for cancer biology research of tumorigenesis, growth, local invasion, and metastasis.

Neonatal overfeeding alters hypothalamic microglial profiles and central responses to immune challenge long-term.

The early life period is one of significant vulnerability to programming effects from the environment. Given the sensitivity of microglial cells to early life programming and to adult diet, we hypothesized overfeeding during the neonatal period would acutely alter microglial profiles within the developing brain, predisposing the individual to a lasting central pro-inflammatory profile that contributes to overactive immune responses long-term. We tested this idea by manipulating litter sizes in which Wistar rat pups were raised, so the pups were suckled in litters of 4 (neonatally overfed) or 12 (control). This manipulation induces obesity and susceptibility to lipopolysaccharide (LPS) long-term. We then examined microglial and central pro-inflammatory profiles during development and in adulthood as well as susceptibility to neuroimmune challenge with LPS. Neonatally overfed rats have evidence of microgliosis in the paraventricular nucleus of the hypothalamus (PVN) as early as postnatal day 14. They also show changes in hypothalamic gene expression at this time, with suppressed hypothalamic interleukin 1ß mRNA. These effects persist into adulthood, with basal PVN microgliosis and increased hypothalamic toll-like receptor 4, nuclear factor κB, and interleukin 6 gene expression. These neonatally overfed rats also have dramatically exacerbated microglial activation in the PVN 24h after an adult LPS challenge, coupled with changes in inflammatory gene expression. Thus, it appears neonatal overfeeding sensitizes PVN microglia, contributing to a basal pro-inflammatory profile and an altered response to a neuroimmune challenge throughout life. It remains to be seen if these effects can be reversed with early interventions.

Effects of mild calorie restriction on anxiety and hypothalamic-pituitary-adrenal axis responses to stress in the male rat.

Abstract Chronic calorie restriction (CR) is one of the few interventions to improve longevity and quality of life in a variety of species. It also reduces behavioral indices of anxiety and influences some stress hormones under basal conditions. However, it is not known how CR influences hypothalamic-pituitary-adrenal (HPA) axis function or if those on a CR diet have heightened HPA axis responses to stress. We hypothesized elevated basal glucocorticoid levels induced by CR would lead to exacerbated HPA axis responses to the psychological stress, restraint, in the male rat. We first confirmed rats fed 75% of their normal calorie intake for 3 weeks were less anxious than ad libitum-fed (AD) rats in the elevated plus maze test for anxiety. The anxiolytic effect was mild, with only grooming significantly attenuated in the open field and no measured behavior affected in the light/dark box. Despite elevated basal glucocorticoids, CR rats had very similar hormonal and central responses to 15-min restraint to the AD rats. Both CR and AD rats responded to restraint stress with a robust increase in glucocorticoids that was resolved by 60 min. Both groups also showed robust neuronal activation in the paraventricular nucleus of the hypothalamus and in other stress- and feeding-sensitive brain regions that was not substantially affected by calorie intake. Our findings thus demonstrate chronic mild CR is subtly anxiolytic and is not likely to affect HPA axis responses to psychological stress. These findings support research suggesting a beneficial effect of mild CR.

Neonatal overfeeding attenuates acute central pro-inflammatory effects of short-term high fat diet.

Neonatal obesity predisposes individuals to obesity throughout life. In rats, neonatal overfeeding also leads to early accelerated weight gain that persists into adulthood. The phenotype is associated with dysfunction in a number of systems including paraventricular nucleus of the hypothalamus (PVN) responses to psychological and immune stressors. However, in many cases weight gain in neonatally overfed rats stabilizes in early adulthood so the animal does not become more obese as it ages. Here we examined if neonatal overfeeding by suckling rats in small litters predisposes them to exacerbated metabolic and central inflammatory disturbances if they are also given a high fat diet in later life. In adulthood we gave the rats normal chow, 3 days, or 3 weeks high fat diet (45% kcal from fat) and measured peripheral indices of metabolic disturbance. We also investigated hypothalamic microglial changes, as an index of central inflammation, as well as PVN responses to lipopolysaccharide (LPS). Surprisingly, neonatal overfeeding did not predispose rats to the metabolic effects of a high fat diet. Weight changes and glucose metabolism were unaffected by the early life experience. However, short term (3 day) high fat diet was associated with more microglia in the hypothalamus and a markedly exacerbated PVN response to LPS in control rats; effects not seen in the neonatally overfed. Our findings indicate neonatally overfed animals are not more susceptible to the adverse metabolic effects of a short-term high fat diet but may be less able to respond to the central effects.

Endogenous ghrelin's role in hippocampal neuroprotection after global cerebral ischemia: does endogenous ghrelin protect against global stroke?

Ghrelin is a gastrointestinal hormone with a well-characterized role in feeding and metabolism. Recent evidence suggests that ghrelin may also be neuroprotective after injury in animal models of cerebral ischemia. Thus exogenous ghrelin treatment can improve cell survival, reduce infarct size, and rescue memory deficits in focal ischemia models, doing so by suppressing inflammation and apoptosis. Endogenous ghrelin plays a key a role in a number of physiological processes, including feeding, metabolism, stress, and anxiety. However, no study has examined whether endogenous ghrelin also contributes to neuroprotection after cerebral ischemia. Here, we aimed to determine whether endogenous ghrelin normally protects against neuronal cell death and cognitive impairments after global cerebral ischemia and whether such changes are linked with inflammation or apoptosis. We used a two-vessel occlusion (2VO) model of global cerebral ischemia in wild-type (wt) and ghrelin knockout (ghr-/-) C57/Bl6J mice. ghr-/- mice had improved cell survival in the Cornu Ammonis(CA)-2/3 region of the hippocampus-a region of significant growth hormone secretagogue receptor expression. They also displayed less cellular degeneration than wt mice after the 2VO (Fluoro-Jade) and had less cognitive impairment in the novel object-recognition test. These outcomes were despite evidence of more neuroinflammation and apoptosis in the ghr-/- and less of a postsurgery hypothermia. Finally, we found that mortality in the week following the 2VO was reduced more in ghr-/- mice than in wt. Overall, these experiments point to a neurodegenerative but antiapoptotic effect of endogenous ghrelin in this model of global ischemia, highlighting that further research is essential before we can apply ghrelin treatments to neurodegenerative insults in the clinic.

Studies on the improved thermal stability for doped ordered mesoporous γ-alumina.

Ordered mesoporous γ-alumina (OMA), Ce-doped, Zr-doped and Ce-Zr-codoped OMA samples were synthesized in a sol-gel system with P123 as the soft template, both salicylic acid and citric acid as the assistant templates. The results show that the incorporations of either cerium or zirconium or both are able to improve the thermal stability of OMA. The capability to preserve the structural ordering and suppress the phase transition from γ-Al2O3 to α-Al2O3 at high temperature observed on the doped OMA is due to the formation of CeO2, ZrO2 or Ce(x)Zr(1-x)O2 phase, which is capable of protecting OMA from the structural collapse by sintering and phase transition.

Synthesis of highly dispersed ceria-zirconia supported on ordered mesoporous alumina.

Highly dispersed ceria-zirconia supported on ordered mesoporous alumina, showing higher thermal stability up to 900 °C, has been successfully synthesized via a sol-gel process associated with P123 as the template in ethanol solvent.

[Determination of palladium in automobile exhaust catalysts by FAAS method].

Palladium in automotive exhaust catalyst was determined by flame atomic absorption spectrometry (FAAS). The analytical conditions and the coexisting elements interference were studied. The catalyst was dissolved by the mixture of H2O2 and HCl. Pd in the solution was directly determined by FAAS method. The linearity of working curve ranges from 0.1 to 15 microg x mL(-1); the detection limit is 0.029 microg x mL(-1); the relative standard deviation (RSD) range is from 0.8% to 2.5%; and the recovery rate range is from 99.6% to 101.2%. It is a simple and convenient method for accurate analysis of Pd in the exhaust catalysts.

[Effects of pH value during synthesis on the structure and performance of ceria zirconia mixed oxides].

Heating reflux aging technology was first applied to obtain a series of ceria zirconia mixed oxides composed of 0.6CeO2-0.4ZrO2. N2 physical adsorption, FT-Raman, and UV-Vis diffuse spectroscopy techniques were preformed to investigate the relationships between the structure and oxygen storage capacity of ceria zirconia mixed oxides prepared at different pH value of precipitation. The composition of ceria zirconia mixed oxides fluctuated with the pH value of precipitation, leading to the variation in phase ingredients, defects, crystallization and texture. Controlling the pH value of precipitation at 10.5-11.0 can avoid the introduction of Si, improve the texture, phase homogeneity and defects concentration, decrease the degree of crystallization, and increase the oxygen storage capacity.

[The relationship between structure and oxygen storage capacity of Ce(x)Zr(1-x)O2 solid solution].

Heating reflux aging technology was applied to prepare a series of Ce(x)Zr(1-x)O2 (0.25 < or = x < or = 1) solid solution. The effects of the Ce(x)Zr(1-X)O2 composition on the structure and oxygen storage capacity were characterized using N2 physical adsorp tion, X-ray diffraction (XRD), FT-Raman, UV-Vis diffuse spectroscopy techniques. The texture, structure and thermal stability of ceria-zirconia mixed oxides are closely related to the ratio of cerium to zirconium in the solid solution, with increasing the zirconium content, the specific area increases, and the structure undergoes a change of order --> disorder --> order. Among them, Ce(0.4Zr(0.6)O2 sample possesses the maximum OSC and Ce(0.25)Zr(0.75)O2 sample possesses the best thermal stability.

[Study on the ultraviolet-visible spectra of Au/Al2O3 catalysts].

A variety of synthesis parameters for the preparation of gold nanoparticles by NaBH4 solution reduction in the W/O microemulsion media consisting of Cetyl Trimethyl Ammonium Bromide (CTAB)/n-hexanol/water system was investigated. The results showed that the molar ratio of water to surfactant (rw) had nothing to do with the gold particle size, but the concentration of the aqueous gold salt solution had a significant effect on the size of gold particle. Through optimizing the preparation parameters, Au/Al2O3 catalysts were prepared with two different methods, then the catalysts were characterized by ultraviolet-visible spectra, XRD and TEM, and the effect of two different preparation methods on active component gold particle size in the catalysts was studied.