The Effect of Bumpy Structure on Optical Properties of Bimetallic Nanoshells

In this paper, a sensitive bumpy bimetallic nanoshell for detection of thyroid cancer market (Thyroglobulin, Tg) and bovine serum albumin (BSA) proteins is reported. The physical origin of plasmonic properties of bimetal nanoshells is described by plasmon hybridization theory which indicates three intense and clearly separated plasmon modes. The electric field intensity enhancement of the bumpy bimetal nanoshell increases by ~559 %, at the surface of the bump in comparison with a smooth shell. The presence of bumpy structure on the nanoshell surface provides a high enhancement of the resulting Raman signal through an electromagnetic field of the order of 10⁷ which leads to an increase in sensitivity detection of Tg and BSA proteins. In addition, a refractive index (RI) sensitivity of 332.54 nm/RIU is achieved for this bumpy bimetallic nanoshell.     

AKT/FOXO signaling enforces reversible differentiation blockade in myeloid leukemias

AKT activation is associated with many malignancies, where AKT acts, in part, by inhibiting FOXO tumor suppressors. We show a converse role for AKT/FOXOs in acute myeloid leukemia (AML). Rather than decreased FOXO activity, we observed that FOXOs are active in ～40% of AML patient samples regardless of genetic subtype. We also observe this activity in human MLL-AF9 leukemia allele-induced AML in mice, where either activation of Akt or compound deletion of FoxO1/3/4 reduced leukemic cell growth, with the latter markedly diminishing leukemia-initiating cell (LIC) function in vivo and improving animal survival. FOXO inhibition resulted in myeloid maturation and subsequent AML cell death. FOXO activation inversely correlated with JNK/c-JUN signaling, and leukemic cells resistant to FOXO inhibition responded to JNK inhibition. These data reveal a molecular role for AKT/FOXO and JNK/c-JUN in maintaining a differentiation blockade that can be targeted to inhibit leukemias with a range of genetic lesions.     

Salicylic acid affects growth,essential oil and chemical compositions of thyme (Thymus daenensis Celak.) under reduced irrigation

Salicylic acid (SA) may reduce the negative impact of water deficit on growth and metabolite yield of Thymus daenensis Celak subsp. daenensis Celak. The effect of foliar application of SA and reduced irrigation on growth, oil yield, chemical components, and antibacterial and antioxidant activities of T. daenensis in field condition were investigated. Treatments comprised 0.0, 1.5 and 3.0 M SA applied to plants under normal irrigation and stressed conditions. Results indicated that irrigation regime had a significant effect on growing degree days (GDD) required to reach early and full flowering. Foliar application of SA influenced GDD from early growing stage to 50 % and full flowering, minimum radius and canopy diameter. The highest values of oil content (3.2 % v/w) and yield (14.9 g m^?2) were obtained from application of 3.0 M SA. Percentage of some chemical constituents in the essential oil extracted from the plants under stress was higher than non-stressed plants. Thymol content was significantly reduced under stressed conditions. Foliar application of SA significantly improved carvacrol, α-thujene, α-pinene and p-cymene contents in the oils, but reduced thymol and, β-caryophyllene amounts. Our results showed that foliar application of SA reduced the negative effect of water deficit on thymol content in the essential oil of T. daenensis. The essential oils of T. daenensis exhibited antioxidant and antibacterial activities when plants were sprayed with 1.5 and 3.0 M SA, respectively.     

Molecular Basis for Preventing α-Synuclein Aggregation by a Molecular Tweezer

Recent work on α-synuclein has shown that aggregation is controlled kinetically by the rate of reconfiguration of the unstructured chain, such that the faster the reconfiguration, the slower the aggregation. In this work we investigate this relationship by examining α-synuclein in the presence of a small molecular tweezer, CLR01, which binds selectively to Lys side chains. We find strong binding to multiple Lys within the chain as measured by fluorescence and mass-spectrometry and a linear increase in the reconfiguration rate with concentration of the inhibitor. Top-down mass-spectrometric analysis shows that the main binding of CLR01 to α-synuclein occurs at the N-terminal Lys-10/Lys-12. Photo-induced cross-linking of unmodified proteins (PICUP) analysis shows that under the conditions used for the fluorescence analysis, α-synuclein is predominantly monomeric. The results can be successfully modeled using a kinetic scheme in which two aggregation-prone monomers can form an encounter complex that leads to further oligomerization but can also dissociate back to monomers if the reconfiguration rate is sufficiently high. Taken together, the data provide important insights into the preferred binding site of CLR01 on α-synuclein and the mechanism by which the molecular tweezer prevents self-assembly into neurotoxic aggregates by α-synuclein and presumably other amyloidogenic proteins.     

Removal of heavy metals from industrial wastewater using microbial fuel cell

Removal efficiency of gold from a solution of pure tetrachloroaurate ions was investigated using microbial fuel cell (MFC) technology. The effects of type of catholyte solution and initial gold concentration on the removal efficiency were considered. Due to its presence at high levels in the gold wastewater, the effect of copper ions on the removal efficiency of the gold ions was also studied. The effects of pH and initial biomass concentration on the gold removal efficiency was also determined. The results showed that after 5 h contact time, 95% of gold removal efficiency from a wastewater containing 250 ppm of initial gold ions at ambient temperature using 80 g/L yeast concentration was achieved. After 48 h of the cell''s operation under the same condition, 98.86% of AuCl₄ ^– ions were successfully removed from the solution. At initial gold concentration in the waste solution of 250 ppm, pH 2, and initial yeast concentration of 80 g/L, 100% removal efficiency of the gold was achieved. On the other hand, the most suitable condition for copper removal was found at a pH of 5.2, where 53% removal efficiency from the waste solution was accomplished.     

Enhanced Thermal Stability and Biocompatibility of Gold Nanorods by Graphene Oxide

In the present study, the effect of nanosized graphene oxide layer on thermal stability and biocompatibility of gold nanorods has been examined. The graphene oxide-wrapped gold nanorods were prepared by electrostatic interaction between negatively charged graphene oxide and positively charged nanorods. The resulting nanohybrids were then heated at different time intervals to 95 °C in a water bath to assess the effect of heat on the rods morphology. The structural changes in gold nanorods were monitored via UV-Vis spectroscopy measurements and transmission electron microscopy images. In similar experiments, the graphene oxide used to wrap gold nanorods was reduced by ascorbic acid in a 95 °C water bath. Our results indicate that while bare gold nanorods are highly vulnerable to elevated temperatures, graphene oxide and reduced graphene oxide-coated gold nanorods remain thermally stable with no structural changes. We also confirmed that the enhanced thermal stability is highly dependent on the concentration of deposited graphene oxide available on the surface of the gold nanorods. In addition, we performed an MTT (3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazoliumbromide) assay to make a comparison between the cytotoxicity of the nanohybrids and their primary building blocks on human dermal fibroblast cells as a normal cell line. We found evidence that graphene oxide can enhance the biocompatibility of the rods through covering toxic chemicals on the surface of them.

Open image in new window

Graphical Abstract ?

     

Assessment of genetic markers and glioblastoma stem-like cells in activation of dendritic cells

Glioblastoma (GBM) is the most common and aggressive intraparenchymal primary brain tumor in adults. The principal reasons for the poor outcomes of GBM are the high rates of recurrence and resistance to chemotherapy. The aim of this study was to determine the role of tailored cellular therapy for GBM with a poor prognosis and compare the activity of dendritic cells (DCs) that have encountered GBM cells. Detecting the correlations between methylation and expression of MGMT and PTEN genes and GBM cancer stem cells (CSCs) markers after co-cultures with a mononuclear cell cocktail are also aims for this study. Allogenic umbilical cord blood (UCB)-derived DCs were labeled with the CD11a and CD123 for immature DCs, and CD80 and CD11c for mature DCs. CD34, CD45, and CD56 cells were isolated from allogenic UCB for using in DCs maturation. GBM CSCs were detected with CD133/1 and CD111 antibodies after co-culture studies. DC activation was carried out via GBM cells including CD133 and CD111 cells and a mononuclear cells cocktail including CD34, CD45, and CD56 natural killer cells. Real-time PCR was performed to detect the expression and promoter methylation status of PTEN and MGMT genes. The expression of CSCs markers was found in all GBM cases, and a statistically significant correlation was found among them after co-culture studies. The most pronounced affinity of DCs to GBM cells was observed at dilutions between 1/4 and 1/256 in co-cultures. There was a statistically significant correlation between cellularity and granularity ratios for CD123 and CD11c. PTEN and MGMT gene expression and methylation values were evaluated with respect to CSCs expression and no statistical significance was found. Activation of DCs might associate with CSCs and the mononuclear cells cocktail including CD34, CD45, and CD56 cells which were obtained from allogenic UCB.     

Whole Blood Selenium Levels in Healthy Adults from the West of Algeria

The purpose of this study was to assess whole blood selenium levels of 300 healthy adults living in four selected areas of the west of Algeria. Selenium was measured using differential pulse cathodic stripping voltammetry with a detection limit of 29.20 μg/L. The mean of whole blood selenium concentrations was 85.65 ± 21.60 μg/L ranging between 30.90 and 144.04 μg/L. This concentration did not vary significantly (P > 0.05) in relation to the gender of the subject, with concentrations of 87.75 ± 21.30 μg/L in men and 83.95 ± 21.60 μg/L in women group. Individuals older than 60 years had a whole blood selenium concentration significantly lower than the rest of the population. However, the measured selenium concentrations in the residential areas were not statistically different (P > 0.05). A total of 32 (10.70%) individuals exhibited whole blood selenium level below 60 μg/L. These results are similar to those of some European countries but are much lower than data observed in USA or seleniferous regions.     

A nonlinear homogenized finite element analysis of the primary stability of the bone–implant interface

Stability of an implant is defined by its ability to undergo physiological loading–unloading cycles without showing excessive tissue damage and micromotions at the interface. Distinction is usually made between the immediate primary stability and the long-term, secondary stability resulting from the biological healing process. The aim of this research is to numerically investigate the effect of initial implantation press-fit, bone yielding, densification and friction at the interface on the primary stability of a simple bone–implant system subjected to loading–unloading cycles. In order to achieve this goal, human trabecular bone was modeled as a continuous, elasto-plastic tissue with damage and densification, which material constants depend on bone volume fraction and fabric. Implantation press-fit related damage in the bone was simulated by expanding the drilled hole to the outer contour of the implant. The bone–implant interface was then modeled with unilateral contact with friction. The implant was modeled as a rigid body and was subjected to increasing off-axis loading cycles. This modeling approach is able to capture the experimentally observed primary stability in terms of initial stiffness, ultimate force and progression of damage. In addition, it is able to quantify the micromotions around the implant relevant for bone healing and osseointegration. In conclusion, the computationally efficient modeling approach used in this study provides a realistic structural response of the bone–implant interface and represents a powerful tool to explore implant design, implantation press-fit and the resulting risk of implant failure under physiological loading.