New Hybrid Nanomaterial Based on Self-Assembly of Cyclodextrins and Cobalt Prussian Blue Analogue Nanocubes

Supramolecular self-assembly has been demonstrated to be a useful approach to developing new functional nanomaterials. In this work, we used a cobalt Prussian blue analogue (PBA, Co₃[Co(CN)₆]₂) compound and a β-cyclodextrin (CD) macrocycle to develop a novel host-guest PBA-CD nanomaterial. The preparation of the functional magnetic material involved the self-assembly of CD molecules onto a PBA surface by a co-precipitation method. According to transmission electronic microscopy results, PBA-CD exhibited a polydisperse structure composed of 3D nanocubes with a mean edge length of 85 nm, which became shorter after CD incorporation. The supramolecular arrangement and structural, crystalline and thermal properties of the hybrid material were studied in detail by vibrational and electronic spectroscopies and X-ray diffraction. The cyclic voltammogram of the hybrid material in a 0.1 mol·L⁻¹ NaCl supporting electrolyte exhibited a quasi-reversible redox process, attributed to Co²⁺/Co³⁺ conversion, with an E_1/2 value of 0.46 V (vs. SCE), with higher reversibility observed for the system in the presence of CD. The standard rate constants for PBA and PBA-CD were determined to be 0.07 and 0.13 s⁻¹, respectively, which suggests that the interaction between the nanocubes and CD at the supramolecular level improves electron transfer. We expect that the properties observed for the hybrid material make it a potential candidate for (bio)sensing designs with a desirable capability for drug delivery.     

A New HPLC-MS Method for Measuring Maslinic Acid and Oleanolic Acid in HT29 and HepG2 Human Cancer Cells

Maslinic acid (MA) and oleanolic acid (OA), the main triterpenic acids present in olive, have important properties for health and disease prevention. MA selectively inhibits cell proliferation of the HT29 human colon-cancer cell line by inducing selective apoptosis. For measuring the MA and OA concentration inside the cell and in the culture medium, a new HPLC-MS procedure has been developed. With this method, a determination of the amount of MA and OA incorporated into HT29 and HepG2 human cancer-cell lines incubated with different concentrations of MA corresponding to 50% growth inhibitory concentration (IC₅₀), IC_50/2, IC_50/4, and IC_50/8 has been made. The results demonstrate that this method is appropriate for determining the MA and OA concentration in different types of cultured cells and reveals the specific dynamics of entry of MA into HT29 and HepG2 cells.     

Base Modification Strategies to Modulate Immune Stimulation by an siRNA

Immune stimulation triggered by siRNAs is one of the major challenges in the development of safe RNAi‐based therapeutics. Within an immunostimulatory siRNA sequence, this hurdle is commonly addressed by using ribose modifications (e.g., 2′‐OMe or 2′‐F), which results in decreased cytokine production. However, as immune stimulation by siRNAs is a sequence‐dependent phenomenon, recognition of the nucleobases by the trigger receptor(s) is also likely. Here, we use the recently published crystal structures of Toll‐like receptor 8 (TLR8) bound to small‐molecule agonists to generate computational models for ribonucleotide binding by this immune receptor. Our modeling suggested that modification of either the Watson–Crick or Hoogsteen face of adenosine would disrupt nucleotide/TLR8 interactions. We employed chemical synthesis to alter either the Watson–Crick or Hoogsteen face of adenosine and evaluated the effect of these modifications in an siRNA guide strand by measuring the immunostimulatory and RNA interference properties. For the siRNA guide strand tested, we found that modifying the Watson–Crick face is generally more effective at blocking TNFα production in human peripheral blood mononuclear cells (PBMCs) than modification at the Hoogsteen edge. We also observed that modifications near the 5′‐end were more effective at blocking cytokine production than those placed at the 3′‐end. This work advances our understanding of how chemical modifications can be used to optimize siRNA performance.     

The Fuzzy Project Scheduling Problem with Minimal Generalized Precedence Relations

In scheduling, estimations are affected by the imprecision of limited information on future events, and the reduction in the number and level of detail of activities. Overlapping of processes and activities requires the study of their continuity, along with analysis of the risks associated with imprecision. In this line, this article proposes a fuzzy heuristic model for the Project Scheduling Problem with flows and minimal feeding, time and work Generalized Precedence Relations with a realistic approach to overlapping, in which the continuity of processes and activities is allowed in a discretionary way. This fuzzy algorithm handles the balance of process flows, and computes the optimal fragmentation of tasks, avoiding the interruption of the critical path and reverse criticality. The goodness of this approach is tested on several problems found in the literature; furthermore, an example of a 15‐story building was used to compare the better performance of the algorithm implemented in Visual Basic for Applications (Excel) over that same example input in Primavera© P6 Professional V8.2.0, using five different scenarios.     

Temporal variability of nitrate transport through hydrological response during flood events within a large agricultural catchment in south-west France

The temporal variability of nitrate transport was monitored continuously in a large agricultural catchment, the 1110 km² Save catchment in south-west France, from January 2007 to June 2009. The overall aim was to analyse the temporal transport of nitrate through hydrological response during flood events in the catchment. Nitrate loads and hysteresis were also analysed and the relationships between nitrate and hydro-climatological variables within flood events were determined. During the study period, 19 flood events were analysed using extensive datasets obtained by manual and automatic sampling. The maximum NO₃⁻ concentration during flood varied from 8.2 mg l⁻¹ to 41.1 mg l⁻¹ with flood discharge from 6.75 m³ s⁻¹ to 112.60 m³ s⁻¹. The annual NO₃⁻ loads in 2007 and 2008 amounted to 2514 t and 3047 t, respectively, with average specific yield of 2.5 t km⁻¹² yr⁻¹. The temporal transport of nitrate loads during different seasonal flood events varied from 12 t to 909 t. Nitrate transport during flood events amounted to 1600 t (64% of annual load; 16% of annual duration) in 2007 and 1872 t (62% of annual load; 20% of annual duration) in 2008. The level of peak discharge during flood events did not control peak nitrate concentrations, since similar nitrate peaks were produced by different peak discharges. Statistically strong correlations were found between nitrate transport and total precipitation, flood duration, peak discharge and total water yield. These four variables may be the main factors controlling nitrate export from the Save catchment. The relationship between nitrate and discharge (hysteresis patterns) investigated through flood events in this study was mainly dominated by anticlockwise behaviour.     

The future of security in Wireless Multimedia Sensor Networks

This is a position paper on our views on security aspects of Wireless Multimedia Sensor Networks (Secure WMSNs). It is meant to serve as a brief survey. But, more importantly, it gives a perspective on how we foresee the future of this research area, its main challenges, and its future trends. We believe that this paper will spur new discussions and research ideas among the researchers from both the industry and the academic world.