Biocompatible nano-micro-particles by solvent evaporation from multiple emulsions technique

In this study, a method based on a multiple emulsions system was developed for the production of polymeric nano and micro-vectors. The possibility to apply an unified preparation technique to different polymers, such as polyesters [polycaprolactone, poly-dl-lactide, poly(dl-lactide-co-caprolactone) = 70/30] and polyacrylates [poly(methylmethacrylate–acrylic acid) = 73/27], loaded with different model molecules (budesonide, tamoxifen, and α-tocopherol) was explored. After selecting the best operating conditions, especially for emulsification and separation, the technique proved to be readily adaptable for production of both nano and micro-particles with different morphologies, depending on type of polymer, and consequently on solvent used for solubilization: nano-particles, with a round shape and a smooth surface, for polyesters, otherwise micro-particles for the polyacrylate polymer, owing to the presence of hydrophilic co-solvents, that caused both an easy coalescence between the oil and water phases, thus enlarged particles size, and a high porosity. Even the yield of encapsulation was influenced by the presence of hydrophilic co-solvents, causing a higher yield for nano-vectors. Polyesters-based nano-vectors showed release times of molecules, linked to their degradation time, higher than 8 months that make them useful to formulate injectable or implantable drug delivery systems. Polyacrylate-based micro-vectors showed an enteric behavior, interesting for designing solid pharmaceutical formulations for oral delivery. Therefore, the technique demonstrated to assure a broad application in drug delivery research.     

Turning an organic semiconductor into a low-resistance material by ion implantation

We report on the effects of low energy ion implantation on thin films of pentacene, carried out to investigate the efficacy of this process in the fabrication of organic electronic devices. Two different ions, Ne and N, have been implanted and compared, to assess the effects of different reactivity within the hydrocarbon matrix. Strong modification of the electrical conductivity, stable in time, is observed following ion implantation. This effect is significantly larger for N implants (up to six orders of magnitude), which are shown to introduce stable charged species within the hydrocarbon matrix, not only damage as is the case for Ne implants. Fully operational pentacene thin film transistors have also been implanted and we show how a controlled N ion implantation process can induce stable modifications in the threshold voltage, without affecting the device performance.     

A Bayesian hierarchical model for maximizing the vascular adhesion of nanoparticles

The complex vascular dynamics and wall deposition of systemically injected nanoparticles is regulated by their geometrical properties (size, shape) and biophysical parameters (ligand–receptor bond type and surface density, local shear rates). Although sophisticated computational models have been developed to capture the vascular behavior of nanoparticles, it is increasingly recognized that purely deterministic approaches, where the governing parameters are known a priori and conclusively describe behaviors based on physical characteristics, may be too restrictive to accurately reflect natural processes. Here, a novel computational framework is proposed by coupling the physics dictating the vascular adhesion of nanoparticles with a stochastic model. In particular, two governing parameters (i.e. the ligand–receptor bond length and the ligand surface density on the nanoparticle) are treated as two stochastic quantities, whose values are not fixed a priori but would rather range in defined intervals with a certain probability. This approach is used to predict the deposition of spherical nanoparticles with different radii, ranging from 750 to 6,000 nm, in a parallel plate flow chamber under different flow conditions, with a shear rate ranging from 50 to 90  $\text {s}^{-1}$ . It is demonstrated that the resulting stochastic model can predict the experimental data more accurately than the original deterministic model. This approach allows one to increase the predictive power of mathematical models of any natural process by accounting for the experimental and intrinsic biological uncertainties.     

Antiproliferative Effects of the Aptamer d(GGGT)4 and Its Analogues with an Abasic-Site Mimic Loop on Different Cancer Cells

In this paper, we study the {"type":"entrez-nucleotide","attrs":{"text":"T30923","term_id":"613021","term_text":"T30923"}}T30923 antiproliferative potential and the contribution of its loop residues in six different human cancer cell lines by preparing five {"type":"entrez-nucleotide","attrs":{"text":"T30923","term_id":"613021","term_text":"T30923"}}T30923 variants using the single residue replacement approach of loop thymidine with an abasic site mimic (S). G-rich oligonucleotides (GRO) show interesting anticancer properties because of their capability to adopt G-quadruplex structures (G4s), such as the G4 HIV-1 integrase inhibitor {"type":"entrez-nucleotide","attrs":{"text":"T30923","term_id":"613021","term_text":"T30923"}}T30923. Considering the multi-targeted effects of G4-aptamers and the limited number of cancer cell lines tested, particularly for {"type":"entrez-nucleotide","attrs":{"text":"T30923","term_id":"613021","term_text":"T30923"}}T30923, it should be important to find a suitable tumor line, in addition to considering that the effects also strictly depend on G4s. CD, NMR and non-denaturating polyacrylamide gel electrophoresis data clearly show that all modified ODNs closely resemble the dimeric structure of parallel G4s’ parent aptamer, keeping the resistance in biological environments substantially unchanged, as shown by nuclease stability assay. The antiproliferative effects of {"type":"entrez-nucleotide","attrs":{"text":"T30923","term_id":"613021","term_text":"T30923"}}T30923 and its variants are tried in vitro by MTT assays, showing interesting cytotoxic activity, depending on time and dose, for all G4s, especially in MDA-MB-231 cells with a reduction in cell viability approximately up to 30%. Among all derivatives, QS12 results are the most promising, showing more pronounced cytotoxic effects both in MDA-MB-231 and Hela cells, with a decrease in cell viability from 70% to 60%. In summary, the single loop residue S substitution approach may be useful for designing antiproliferative G4s, considering that most of them, characterized by single residue loops, may be able to bind different targets in several cancer cell pathways. Generally, this approach could be of benefit by revealing some minimal functional structures, stimulating further studies aimed at the development of novel anticancer drugs.     

A Smart Procedure for the Femtosecond Laser-Based Fabrication of a Polymeric Lab-on-a-Chip for Capturing Tumor Cell

Rapid prototyping methods for the design and fabrication of polymeric labs-on-a-chip are on the rise, as they allow high degrees of precision and flexibility. For example, a microfluidic platform may require an optimization phase in which it could be necessary to continuously modify the architecture and geometry; however, this is only possible if easy, controllable fabrication methods and low-cost materials are available. In this paper, we describe the realization process of a microfluidic tool, from the computer-aided design (CAD) to the proof-of-concept application as a capture device for circulating tumor cells (CTCs). The entire platform was realized in polymethyl methacrylate (PMMA), combining femtosecond (fs) laser and micromilling fabrication technologies. The multilayer device was assembled through a facile and low-cost solvent-assisted method. A serpentine microchannel was then directly biofunctionalized by immobilizing capture probes able to distinguish cancer from non-cancer cells without labeling. The low material costs, customizable methods, and biological application of the realized platform make it a suitable model for industrial exploitation and applications at the point of care.     

Process optimization by decoupled control of key microbial populations: distribution of activity and abundance of polyphosphate-accumulating organisms and nitrifying populations in a full-scale IFAS-EBPR plant

This study investigated the abundance and distribution of key functional microbial populations and their activities in a full-scale integrated fixed film activated sludge-enhanced biological phosphorus removal (IFAS-EBPR) process. Polyphosphate accumulating organisms (PAOs) including Accumulibacter and EBPR activities were predominately associated with the mixed liquor (>90%) whereas nitrifying populations and nitrification activity resided mostly (>70%) on the carrier media. Ammonia oxidizer bacteria (AOB) were members of the Nitrosomonas europaea/eutropha/halophila and the Nitrosomonas oligotropha lineages, while nitrite oxidizer bacteria (NOB) belonged to the Nitrospira genus. Addition of the carrier media in the hybrid activated sludge system increased the nitrification capacity and stability; this effect was much greater in the first IFAS stage than in the second one where the residual ammonia concentration becomes limiting. Our results show that IFAS-EBPR systems enable decoupling of solid residence time (SRT) control for nitrifiers and PAOs that require or prefer conflicting SRT values (e.g. >15 days required for nitrifiers and <5 days preferred for PAOs). Allowing the slow-growing nitrifiers to attach to the carrier media and the faster-growing phosphorus (P)-removing organisms (and other heterotrophs, e.g. denitrifiers) to be in the suspended mixed liquor (ML), the EBPR-IFAS system facilitates separate SRT controls and overall optimization for both N and P removal processes.     

A major IgE epitope-containing grass pollen allergen domain from Phl p 5 folds as a four-helix bundle

Phl p 5, a 29 kDa major allergen from timothy grass pollen,is one of the most reactive members of group 5 allergens. Itssequence comprises two repeats of a novel alanine-rich motif(AR) whose structure and allergenic response are still mostlyunkown. We report here a structural characterization of an immunodominantfragment of Phl p 5, Phl p 5(56–165) which comprises thefirst AR repeat. Recombinant (r)Phl p 5(56–165) was expressedin Escherichia coli, purified to homogeneity and shown to besufficient to react with serum IgE from 90% of grass pollenallergic patients. Using NMR spectroscopy, we show conclusivelythat the fragment forms a compact globular domain which is,however, prone to degradation with time. The rPhl p 5(56–165)fold consists of a four-helix bundle held together by hydrophobicinteractions between the aromatic rings and aliphatic side chains.This evidence gives clear indications about the structure ofthe full-length Phl p 5 and provides a rational basis for findingways to stabilize the fold and designing therapeutic vaccinesagainst grass pollen allergy.     

Within-plot and within-plant variation for seed content of soya bean protease inhibitors

Experiments were designed to determine the seed content of protease inhibitors in different plants of a plot or at different nodes along the main stem. The inhibitory activity of the samples was measured in vitro using sodium benzoyl-DL-arginine-p-nitroanilide as chromogenic substrate and bovine trypsin as target enzyme. Six soya bean (Glycine max Merr) strains were used, three capable of synthesizing the Kunitz trypsin inhibitor (L62-364, Williams 82, and 594-1) and three lacking this particular function (L81-4590, L81-4871, and L83-4387). In all genotypes on trial, remarkable plant-to-plant variation was found, so that most strains had at least one part of the data distribution in common. Significant differences were also noted for antitryptic activities of seed samples collected at different positions on the main stem. Gradients interior to the plant varied according to the tested strain but those of Williams 82 and of its near isogenic line L81-4590 were very similar, indicating that the amount and type of variation depended on genotype and that changes in the inhibitory activity were attributable to variation in the synthesis of inhibitors other than Kunitz.     

The role of interface DoFs in decoupling of substructures based on the dual domain decomposition

The paper considers the decoupling problem, i.e. the identification of the dynamic behaviour of a structural subsystem, starting from the known dynamic behaviour of the coupled system, and from information about the remaining part of the structural system (residual subsystem). Typically, the FRF matrix of the coupled system is assumed to be known at the coupling DoFs (standard interface). To circumvent ill-conditioning around particular frequencies, some authors suggest the use of FRFs at some internal DoFs of the residual subsystem. In this paper, the decoupling problem is revisited in the general framework of frequency based substructuring. Specifically, the dual domain decomposition is used by adding a fictitious subsystem, which is the negative of the residual subsystem, to the coupled system. In this framework, the use of internal DoFs of the residual subsystem, in addition to coupling DoFs, appears quite natural (extended interface). The effects of using an extended interface are widely discussed: the main drawback is that the problem becomes singular at any frequency. However, this singularity is easily removed by using standard smart inversion techniques. The approach is tested on a discrete system describing a two-speed transmission, using simulated data polluted by noise. Results are compared with those obtained from existing approaches.     

The Scaffold Protein IscU Retains a Structured Conformation in the FeS Cluster Assembly Complex

IscU and IscS are two essential proteins in the machine responsible for the biogenesis of iron–sulfur clusters, prosthetic groups that are involved in several essential functions. The scaffold protein IscU is the temporary acceptor of the cluster that results when the protein forms a 110 kDa complex with the desulfurase IscS. In the absence of zinc, which stabilises the folded state, IscU is present in solution in equilibrium between a structured and an unstructured form. It has been suggested that IscS preferentially binds unstructured IscU, although crystal structures indicate otherwise. To learn more about the IscS–IscU complex, we have used advanced solution NMR techniques to observe directly the state of fold of IscS‐bound IscU. We present unambiguous evidence that IscU is folded in the complex and that the unstructured form does not bind to IscS. Our data correlate with several observations and explain an IscU‐related pathology.