Abstract The luminescent spectra of the RE 2 O 3 -doped P 2 O 5 –CdO–ZnO glasses (RE = Er, and Tb) were investigated to separate the effects of two studied rare-earth elements and the annealing ...regime on the emission performance of the prepared glasses. The glasses undergo a series of collective measurements including UV–visible absorption, luminescence, thermal expansion, XRD, TEM, and FTIR. The optical UV–visible spectra of the two doped glasses reveal a UV band due to undoped glass beside and extra extended 11 peaks with the Er 3+ ions with high distinct features while the Tb 3+ ions samples exhibit peaks within the visible region. These peaks are correlated with transitions from the ground state in each case to specific energy transitions. The overall optical data indicate that the two rare earth ions are present in a stable trivalent state. Under UV excitation, both Er 3+ and Tb 3+ emit a characteristic green light corresponding to 4 S 3/2 → 4 I 15/2 and 5 D 4 → 7 F 5 transitions, respectively. The performance of the green light was identified to be enhanced by increasing the concentration of rare earth and the effect of annealing temperature. Moreover, the intensity of the infrared emission of Er 3+ at 1532 nm corresponds to the ( 4 I 13/2 → 4 I 15/2 ) transition which is assumed to be developed with the effect of heating. The resultant IR spectra show distinct vibrational peaks due to phosphate groups that undergo only minor modifications when doped with rare earth elements or over-annealed.
Polysialic acid (polySia) is a unique carbohydrate polymer expressed on the surface of NCAM (neuronal cell adhesion molecule) in a number of cancers where it modulates cell-cell and cell-matrix ...adhesion, migration, invasion and metastasis and is strongly associated with poor clinical prognosis. We have carried out the first investigation into the effect of polySia expression on the behaviour of cancer cells in hypoxia, a key source of chemoresistance in tumours. The role of polysialylation and associated tumour cell migration and cell adhesion were studied in hypoxia, along with effects on cell survival and the potential role of HIF-1. Our findings provide the first evidence that polySia expression sustains migratory capacity and is associated with tumour cell survival in hypoxia. Initial mechanistic studies indicate a potential role for HIF-1 in sustaining polySia-mediated migratory capacity, but not cell survival. These data add to the growing body of evidence pointing to a crucial role for the polysialyltransferases (polySTs) in neuroendocrine tumour progression and provide the first evidence to suggest that polySia is associated with an aggressive phenotype in tumour hypoxia. These results have significant potential implications for polyST inhibition as an anti-metastatic therapeutic strategy and for targeting hypoxic cancer cells.
Abstract Aim Modafinil was tested for efficacy in decreasing use in methamphetamine-dependent participants, compared to placebo. Methods This was a randomized, double-blind, placebo-controlled study, ...with 12 weeks of treatment and a 4-week follow-up. Eight outpatient substance abuse treatment clinics participated in the study. There were 210 treatment-seekers randomized, who all had a DSM-IV diagnosis of methamphetamine dependence; 68 participants to placebo, 72 to modafinil 200 mg, and 70 to modafinil 400 mg, taken once daily on awakening. Participants came to the clinic three times per week for assessments, urine drug screens, and group psychotherapy. The primary outcome measure was a methamphetamine non-use week, which required all the week's qualitative urine drug screens to be negative for methamphetamine. Results Regression analysis showed no significant difference between either modafinil group (200 or 400 mg) or placebo in change in weekly percentage having a methamphetamine non-use week over the 12-week treatment period ( p = 0.53). Similarly, a number of secondary outcomes did not show significant effects of modafinil. However, an ad-hoc analysis of medication compliance, by urinalysis for modafinil and its metabolite, did find a significant difference in maximum duration of abstinence (23 days vs. 10 days, p = 0.003), between those having the top quartile of compliance (>85% of urines were positive for modafinil, N = 36), and the lower three quartiles of modafinil 200 and 400 mg groups ( N = 106). Conclusions Although these data suggest that modafinil, plus group behavioral therapy, was not effective for decreasing methamphetamine use, the study is probably inconclusive because of inadequate compliance with taking medication.
Highlights • Bupropion SR 150 mg BID, vs. matched placebo, for 12 weeks to 204 treatment-seekers. • 3× per week urines for meth and bupropion levels. No biomarker for placebo. • No significant ...difference between treatment groups in % abstinent in Weeks 11–12. • Bupropion adherence per protocol was achieved by just 47%. • Additional data show wide range of adherence patterns, max levels, and clearance rates.
In the present study, multi-walled carbon nanotubes (MWCNTs) were treated in an acidic mixture solution, made with nitric and sulfuric acids in a ratio of 3:1 by volume. The durations of the ...treatment were 100 and 180 min. The defects of these treated MWCNTs were examined using Raman spectroscopy. The attachment of hydroxyl functional groups to the walls of the MWCNTs were verified using FTIR spectroscopy. The dispersion of CNTs with acid treatment is assessed using UV-Vis spectroscopy and Scanning Electron Microscopy (SEM). The results indicate that the duration of the acid treatment has significant effect on both the degree of defects and functionality of the MWCNT. The compressive strength of mortar increased with the addition of the acid-treated MWCNTs; however, no appreciable difference was noted for the two treatment durations under this study.
Reinforced concrete composite sandwich panels are typically made of two concrete wythes separated by an insulating core of rigid polystyrene foam. The strength of the panels relies mostly on the ...efficiency of the shear connectors between the two concrete wythes. The rigid foam is too weak in shear and provides no contribution to the shear resistance of the connectors. In this paper, autoclaved aerated concrete (AAC) is used as an insulating core in place of foam and its efficiency to transfer shear between the sandwich panel layers is investigated. A total of nine full scale specimens made of rigid foam and AAC are tested under flexural load with varying types of shear connectors. Their ultimate load capacities are compared and their respective modes of failure are discussed. A detailed analysis of the stiffness of the shear connectors is done and used to predict the deflection of the panels under the applied load.
The performance of carbon nanotubes (CNTs) in cement-based composites relies to a great extent on its degree of dispersion. In this work, the performance of two commonly used surfactants; sodium ...dodecyl sulfate (SDS) and Triton X-100, is being compared. The effect of surfactant-to-CNT ratio on dispersion efficiency is studied using ultraviolet-visible (UV-Vis) spectrometry, to determine the optimum surfactant dosage. For the optimum ultrasonication energy, Raman spectroscopy is used to assess the degree of imperfections on CNTs. CNTs-reinforced mortar specimens prepared using Triton X-100 and SDS are tested for compressive and flexural strength. Triton X-100 is shown to exhibit better dispersion efficiency than SDS, leading to greater improvement in flexural and compressive strength. An ultrasonication time of 60 min (19.4 kJ/mL) is shown to be sufficient to achieve proper dispersion, however notable degradation of CNTs was noted beyond 30 min (9.7 kJ/mL) of dispersion leading to a strength reduction.
The position and speed of the piston of pneumatic cylinder are very important parameters in evaluating the pneumatic system performance. Utilization of Pulse Width Modulation (PWM) technique to ...control the Fast Switching Valve (FSV) usually causes fluctuation in the piston motion and accordingly, the system performance deteriorates. The objective of this work is to introduce a novel PWM control technique considering the suitable duty cycles according to the switching frequency in order to improve the FSV characteristics and reduce piston speed fluctuation. A test rig for a simple pneumatic circuit with an FSV as a control element has been designed and realized. The displacement of the piston is measured using a Linear Wire Potentiometer Transducer (LWPT), while its derivative is used to estimate the speed considering a low pass filter to reduce the effect of piston position signal noise. A nonlinear mathematical model is introduced and experimentally validated. The results of both computer simulation and experimental measurements show that the integration between fast switching valve and PWM control signal leads to a quasi-linear relationship between duty cycle and piston speed. Moreover; results proved the successful control of piston speed based on the correct duty cycle and valve switching frequency.
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•Polysialic acid is of significant interest due its roles in biology and disease.•First systematic review of approaches for extraction and characterisation of polysialic acids from ...biological matrices.•Approaches to analysis of the degree of polymerisation of polysialic acid evaluated.•Quantitation considered, including accuracy and limit of detection.
Polysialic acid (polySia) is a unique, well-characterised carbohydrate polymer highly-expressed on the cell surface of neurons in the early stages of mammalian brain development. Post-embryogenesis, it is also re-expressed in a number of tumours of neuroendocrine origin. It plays important roles in modulating cell-cell, and cell-matrix adhesion and migration, tumour invasion and metastasis. Techniques for structural and quantitative characterisation of polySia from tumours and cancer cells are thus essential in exploring the relationship between polySia expression levels and structural and functional changes associated with cancer progression and metastasis. A variety of techniques have been developed to structurally and quantitatively analyse polySia in clinical tissues and other biological samples. In this review, analytical approaches used for the determination of polySia in biological matrices in the past 20 years are discussed, with a particular focus on chemical approaches, and quantitative analysis.
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