Metal oxide nanomaterials in seawater: linking physicochemical characteristics with biological response in sea urchin development

The fate and behavior of nanomaterials (NMs) in environmental media has important consequences for toxicity. The majority of aquatic research to date has focused on NM behavior in freshwater systems. However, pH and salinity differences of seawater affect dissolution and aggregation of NMs. In this study, physical characteristics of metal oxide NMs in seawater were linked with their toxicity to developing sea urchins. The metal oxide NMs TiO₂ and CeO₂ up to 10 mg/L were not toxic to the embryos of the white sea urchin (Lytechinus pictus). In contrast, ZnO NM was highly toxic to these embryos (EC₅₀ = 99.5 μg/L). The toxicity of ZnO NM was not significantly different from bulk ZnO or soluble Zn²⁺ (from ZnSO₄·7H₂O), suggesting that the toxicity of ZnO NM can be attributed to soluble Zn²⁺. Furthermore, solubility data indicate that at the concentrations used in our sea urchin embryo experiments, ZnO NM was rapidly and completely solubilized in seawater. The present study also demonstrated that Fe-doped NMs were less soluble in seawater compared to pure ZnO NMs, but there was no concomitant reduction in toxicity.     

A circularity measurement toolkit for manufacturing SMEs

The development and adoption of the concept of circular economy in the last two decades have been remarkable. However, despite its widespread adoption, little progress has been made regarding its measurement, especially in manufacturing SMEs. This paper, therefore, proposes a Circularity Measurement Toolkit (CMT) which enables the assessment of the degree of circularity in manufacturing SMEs. A conceptual CMT framework, which provided the basis for the proposed tool and that defined the different types of circular practices and a classification or levels of circularity was developed from an extensive literature reviewed. To ensure the structure's accuracy of the proposed CMT in terms of requirements to be measured, the monitoring process and actions involved, the tool was verified through a Delphi-study. Furthermore, its practicality was validated through a case study approach in a manufacturing SME. This paper contributes by filling a gap in the CE measurement field through the proposal of the CMT. Besides providing an evaluation of the degree of circularity in the practices of manufacturing SMEs, companies can also employ the proposed CMT to identify corrective actions or future efforts for the adoption of CE practices.     

Electronic Transport Properties in GaAs/AlGaAs and InSe/InP Finite Superlattices under the Effect of a Non-Resonant Intense Laser Field and Considering Geometric Modifications

In this work, a finite periodic superlattice is studied, analyzing the probability of electronic transmission for two types of semiconductor heterostructures, GaAs/AlGaAs and InSe/InP. The changes in the maxima of the quasistationary states for both materials are discussed, making variations in the number of periods of the superlattice and its shape by means of geometric parameters. The effect of a non-resonant intense laser field has been included in the system to analyze the changes in the electronic transport properties by means of the Landauer formalism. It is found that the highest tunneling current is given for the GaAs-based compared to the InSe-based system and that the intense laser field improves the current–voltage characteristics generating higher current peaks, maintaining a negative differential resistance (NDR) effect, both with and without laser field for both materials and this fact allows to tune the magnitude of the current peak with the external field and therefore extend the range of operation for multiple applications. Finally, the power of the system is discussed for different bias voltages as a function of the chemical potential.     

Reversible Thermal Tuning of All‐Dielectric Metasurfaces

All‐dielectric metasurfaces provide a powerful platform for a new generation of flat optical devices, in particular, for applications in telecommunication systems, due to their low losses and high transparency in the infrared. However, active and reversible tuning of such metasurfaces remains a challenge. This study experimentally demonstrates and theoretically justifies a novel scenario of the dynamical reversible tuning of all‐dielectric metasurfaces based on the temperature‐dependent change of the refractive index of silicon. How to design an all‐dielectric metasurface with sharp resonances by achieving interference between magnetic dipole and electric quadrupole modes of constituted nanoparticles arranged in a 2D lattice is shown. Thermal tuning of these resonances can cause drastic but reciprocal changes in the directional scattering of the metasurface in a spectral window of 75 nm. This change can result in a 50‐fold enhancement of the radiation directionality. This type of reversible tuning can play a significant role in novel flat optical devices including the metalenses and metaholograms.     

Characterization of Phages YuuY,KaiHaiDragon, and OneinaGillian Isolated from Microbacterium foliorum

Microbacterium foliorum is a Gram-positive bacteria found in organic matter. Three lytic bacteriophages, KaiHaiDragon, OneinaGillian, and YuuY, were isolated from M. foliorum strain NRRL B-24224. Phage YuuY in particular expresses a broad host range as it possesses the ability to infect closely related bacterial species Microbacterium aerolatum at a high plating efficiency. Characterization tests were performed on all three Microbacterium phage to assess morphology, genomic characteristics, pH and thermal stabilities, life cycle, and the type of receptor used for infection. All three phages showed similar pH stability, ranging from pH 5–11, except for KaiHaiDragon, which had a reduced infection effectiveness at a pH of 11. YuuY possessed a significantly higher temperature tolerance compared to the other Microbacterium phages as some phage particles remained viable after incubation temperatures of up to 80 °C. Based on the one-step growth curve assay, all three Microbacterium phages possessed a relatively short latent period of 90 min and an approximately two-fold burst size factor. Moreover, all three phages utilize a carbohydrate receptor to initiate infection. Based on bioinformatics analysis, YuuY, KaiHaiDragon and OneinaGillian were assigned to clusters EA10, EC, and EG, respectively.     

Evaluation of Phage Display Biopanning Strategies for the Selection of Anti-Cell Surface Receptor Antibodies

Monoclonal antibodies (mAbs) are one of the most successful and versatile protein-based pharmaceutical products used to treat multiple pathological conditions. The remarkable specificity of mAbs and their affinity for biological targets has led to the implementation of mAbs in the therapeutic regime of oncogenic, chronic inflammatory, cardiovascular, and infectious diseases. Thus, the discovery of novel mAbs with defined functional activities is of crucial importance to expand our ability to address current and future clinical challenges. In vitro, antigen-driven affinity selection employing phage display biopanning is a commonly used technique to isolate mAbs. The success of biopanning is dependent on the quality and the presentation format of the antigen, which is critical when isolating mAbs against membrane protein targets. Here, we provide a comprehensive investigation of two established panning strategies, surface-tethering of a recombinant extracellular domain and cell-based biopanning, to examine the impact of antigen presentation on selection outcomes with regards to the isolation of positive mAbs with functional potential against a proof-of-concept type I cell surface receptor. Based on the higher sequence diversity of the resulting antibody repertoire, presentation of a type I membrane protein in soluble form was more advantageous over presentation in cell-based format. Our results will contribute to inform and guide future antibody discovery campaigns against cell surface proteins.     

EXACT: an extensible approach to active object-oriented databases

Active database management systems (DBMSs) are a fast-growing area of research, mainly due to the large number of applications which can benefit from this active dimension. These applications are far from being homogeneous, requiring different kinds of functionalities. However, most of the active DBMSs described in the literature only provide a fixed, hard-wired execution model to support the active dimension. In object-oriented DBMSs, event-condition-action rules have been propo sed for providing active behaviour. This paper presents EXACT, a rule manager for object-oriented DBMSs which provides a variety of options from which the designer can choose the one that best fits the semantics of the concept to be supported by rules. Due to the difficulty of foreseeing future requirements, special attention has been paid to making rule management easily extensible, so that the user can tailor it to suit specific applications. This has been borne out by an implementation in ADAM, an object -oriented DBMS. An example is shown of how the default mechanism can be easily extended to support new requirements. Edited by Y. Vassiliou. Received May 26, 1994 / Revised January 26, 1995, June 22, 1996 / Accepted November 4, 1996     

Vitamin D-Related Single Nucleotide Polymorphisms as Risk Biomarker of Cardiovascular Disease

Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels. In addition to environmental risk factors, genetic predisposition increases the risk; this includes alterations in the vitamin D receptor gene (VDR). These alterations play a key role in modifying vitamin D uptake, being able to modify its function and increasing susceptibility to cardiovascular disorders. The aim of this study was to evaluate the association of polymorphisms in the VDR gene and risk of CVD in a Caucasian population. A retrospective case-control study was conducted comprising 246 CVD patients and 246 controls of Caucasian origin from Southern Spain. The genetic polymorphisms BsmI (rs1544410), TaqI (rs731236), ApaI (rs7975232), FokI (rs2228570) and Cdx2 (rs11568820) were determined by means of real-time polymerase chain reaction (PCR) for allelic discrimination using TaqMan^® probes. The logistic regression analysis adjusted for body mass index and diabetes revealed that the TT genotype was associated with a higher risk of CVD in both the genotypic model (p = 0.0430; OR = 2.30; 95% CI = 1.06–5.37; TT vs. CC) and the recessive model (p = 0.0099; OR = 2.71; 95% CI = 1.31–6.07; TT vs. C). Haplotype analysis revealed that the haplotype GAC (p = 0.047; OR = 0.34; 95% CI = 0.12–0.98) was associated with increased risk of CVD. The VDR polymorphisms FokI (rs2228570) was significantly associated with the development of CVD. No influence was observed of the VDR polymorphisms BsmI (rs1544410), TaqI (rs731236), ApaI (rs7975232) and Cdx2 (rs11568820) on the risk of developing CVD in the patients studied.