Antimicrobial peptides and pregnancy

Antimicrobial peptides (AMPs) are small proteins produced by epithelial surfaces and inflammatory cells, which have broad-spectrum antimicrobial and immunomodulatory activities. They are known to be important in a number of infectious and inflammatory conditions and have been shown to be present in a number of sites throughout the female reproductive tract. Inflammation and infection are associated with a number of complications of pregnancy including preterm labor, and AMPs may play a key role in maintaining and protecting pregnancy. The aim of this review is to describe the expression and function of AMPs in the pregnant female reproductive tract and their relation to preterm labor.     

Development and validation of a new LC–MS/MS method for the simultaneous determination of six major ergot alkaloids and their corresponding epimers. Application to some food and feed commodities

A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed and validated for the simultaneous determination of six major ergot alkaloids, ergometrine, ergosine, ergotamine, ergocornine, ergokryptine and ergocristine, as well as their corresponding epimers in food and feed samples. The method involves extraction under alkaline conditions and subsequent clean-up by applying a simple and rapid liquid–liquid partitioning procedure prior to LC–MS/MS analysis. Evaluation of the method revealed good linearity, accuracy and precision. The limits of quantification varied from 0.1 to 1 μg/kg depending on the analyte and matrix. The average extraction and clean-up recoveries in different matrices were between 45 (only for ergometrine in biscuit) and 90%. The uncertainty associated with the analytical method was not higher than 51% and 30%, at concentration levels of 2.5 and 150 μg/kg respectively. Analyte epimerization proved to be minimal during the analytical procedure. The method has been successfully applied to the determination of ergot alkaloids in some Belgian food and feed commodities. Ergot alkaloids were found in 104 out of 122 samples investigated. Ergosine was the most frequently occurring alkaloid, while the highest levels were observed for ergotamine, ergocristine or ergosine, depending on the product type. The total alkaloid content in positive samples varied from 1 to 1145 μg/kg.     

Succession of bacterial and fungal communities during natural coffee (Coffea arabica) fermentation

Bacteria, yeasts and filamentous fungi were isolated during natural coffee processing. Bacteria were isolated in greater numbers at the beginning of the fermentation, when the moisture of the coffee beans was around 68%. Gram-positive bacteria represented 85.5% of all bacteria isolated, and Bacillus was the predominant genus (51%). Gram-negative species of the genera Serratia, Enterobacter and Acinetobacter were also found. Approximately 22% of 940 randomly chosen isolates of microorganisms were yeasts. Debaryomyces (27%), Pichia (18.9%) and Candida (8.0%) were the most commonly found genera, and these three genera tended to appear more often as the fruit was fermented and dried. Aspergillus was the most abundant genus besides Penicillium, Fusarium and Cladosporium, with 42.6% of the total fungi isolates. The genera and species identified included members known to have pectinase and cellulase activities. Of the 10 organic acids analyzed and quantified in coffee beans, acetic and lactic acids may have been generated by microbial activity. Butyric acid was not detected in any sample.     

Advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness

ABSTRACT

Biofortification aims to improve the micronutrient concentration of staple food crops through the best practices of breeding and modern biotechnology. However, increased zinc and iron concentrations in food crops may not always translate into proportional increases in absorbed zinc (Zn) and iron (Fe). Therefore, assessing iron and zinc bioavailability in biofortified crops is imperative to evaluate the efficacy of breeding programs. This review aimed to investigate the advantages and limitations of in vitro and in vivo methods of iron and zinc bioavailability evaluation in the assessment of biofortification program effectiveness. In vitro, animal and isotopic human studies have shown high iron and zinc bioavailability in biofortified staple food crops. Human studies provide direct knowledge regarding the effectiveness of biofortification, however, human studies are time consuming and are more expensive than in vitro and animal studies. Moreover, in vitro studies may be a useful preliminary screening method to identify promising plant cultivars, however, these studies cannot provide data that are directly applicable to humans. None of these methods provides complete information regarding mineral bioavailability, thus, a combination of these methods should be the most appropriate strategy to investigate the effectiveness of zinc and iron biofortification programs.     

Interior-architectured ZnO nanostructure for enhanced electrical conductivity via stepwise fabrication process

Fabrication of ZnO nanostructure via direct patterning based on sol-gel process has advantages of low-cost, vacuum-free, and rapid process and producibility on flexible or non-uniform substrates. Recently, it has been applied in light-emitting devices and advanced nanopatterning. However, application as an electrically conducting layer processed at low temperature has been limited by its high resistivity due to interior structure. In this paper, we report interior-architecturing of sol-gel-based ZnO nanostructure for the enhanced electrical conductivity. Stepwise fabrication process combining the nanoimprint lithography (NIL) process with an additional growth process was newly applied. Changes in morphology, interior structure, and electrical characteristics of the fabricated ZnO nanolines were analyzed. It was shown that filling structural voids in ZnO nanolines with nanocrystalline ZnO contributed to reducing electrical resistivity. Both rigid and flexible substrates were adopted for the device implementation, and the robustness of ZnO nanostructure on flexible substrate was verified. Interior-architecturing of ZnO nanostructure lends itself well to the tunability of morphological, electrical, and optical characteristics of nanopatterned inorganic materials with the large-area, low-cost, and low-temperature producibility.     

Metrics and Criteria for Quality Assessment of Testable Hw/Sw Systems Architectures

The purpose of this paper is to present a novel methodology for assessing the quality of architecture solutions of hw/sw systems, with particular emphasis on testability. Criteria and metrics for quality assessment are proposed and used to assist the design team in selecting a best-fitted architecture that satisfies not only functional requirements, but also test requirements. The methodology makes use of object-oriented modeling techniques. Near-optimum clustering of methods and attributes into objects is carried out, in such a way that objects with moderate complexity, low coupling and high functional autonomy, result. The main features of the methodology are ascertained through a case study.     

Thiol–Ene Clickable Gelatin: A Platform Bioink for Multiple 3D Biofabrication Technologies

Bioprinting can be defined as the art of combining materials and cells to fabricate designed, hierarchical 3D hybrid constructs. Suitable materials, so called bioinks, have to comply with challenging rheological processing demands and rapidly form a stable hydrogel postprinting in a cytocompatible manner. Gelatin is often adopted for this purpose, usually modified with (meth‐)acryloyl functionalities for postfabrication curing by free radical photopolymerization, resulting in a hydrogel that is cross‐linked via nondegradable polymer chains of uncontrolled length. The application of allylated gelatin (GelAGE) as a thiol–ene clickable bioink for distinct biofabrication applications is reported. Curing of this system occurs via dimerization and yields a network with flexible properties that offer a wider biofabrication window than (meth‐)acryloyl chemistry, and without additional nondegradable components. An in‐depth analysis of GelAGE synthesis is conducted, and standard UV‐initiation is further compared with a recently described visible‐light‐initiator system for GelAGE hydrogel formation. It is demonstrated that GelAGE may serve as a platform bioink for several biofabrication technologies by fabricating constructs with high shape fidelity via lithography‐based (digital light processing) 3D printing and extrusion‐based 3D bioprinting, the latter supporting long‐term viability postprinting of encapsulated chondrocytes.     

Understanding Local and Macroscopic Electron Mobilities in the Fullerene Network of Conjugated Polymer‐based Solar Cells: Time‐Resolved Microwave Conductivity and Theory

The efficiency of bulk heterojunction (BHJ) organic photovoltaics is sensitive to the morphology of the fullerene network that transports electrons through the device. This sensitivity makes it difficult to distinguish the contrasting roles of local electron mobility (how easily electrons can transfer between neighboring fullerene molecules) and macroscopic electron mobility (how well‐connected is the fullerene network on device length scales) in solar cell performance. In this work, a combination of density functional theory (DFT) calculations, flash‐photolysis time‐resolved microwave conductivity (TRMC) experiments, and space‐charge‐limit current (SCLC) mobility estimates are used to examine the roles of local and macroscopic electron mobility in conjugated polymer/fullerene BHJ photovoltaics. The local mobility of different pentaaryl fullerene derivatives (so‐called ‘shuttlecock’ molecules) is similar, so that differences in solar cell efficiency and SCLC mobilities result directly from the different propensities of these molecules to self‐assemble on macroscopic length scales. These experiments and calculations also demonstrate that the local mobility of phenyl‐C₆₀ butyl methyl ester (PCBM) is an order of magnitude higher than that of other fullerene derivatives, explaining why PCBM has been the acceptor of choice for conjugated polymer BHJ devices even though it does not form an optimal macroscopic network. The DFT calculations indicate that PCBM's superior local mobility comes from the near‐spherical nature of its molecular orbitals, which allow strong electronic coupling between adjacent molecules. In combination, DFT and TRMC techniques provide a tool for screening new fullerene derivatives for good local mobility when designing new molecules that can improve on the macroscopic electron mobility offered by PCBM.     

Multi‐Site Functionalization of Protein Scaffolds for Bimetallic Nanoparticle Templating

The use of biological scaffolds to template inorganic material offers a strategy to synthesize precise composite nanostructures of different sizes and shapes. Proteins are unique biological scaffolds that consist of multiple binding regions or epitope sites that site‐specifically associate with conserved amino acid sequences within protein‐binding partners. These binding regions can be exploited as synthesis sites for multiple inorganic species within the same protein scaffold, resulting in bimetallic inorganic nanostructures. This strategy is demonstrated with the scaffold protein clathrin, which self‐assembles into spherical cages. Specifically, tether peptides that noncovalently associate with distinct clathrin epitope sites, while initiating simultaneous synthesis of two inorganic species within the assembled clathrin protein cage, are designed. The flexibility and diversity of this unique biotemplating strategy is demonstrated by synthesizing two types of composite structures (silver–gold mixed bimetallic and silver–gold core–shell nanostructures) from a single clathrin template. This noncovalent, Template Engineering Through Epitope Recognition, or TEThER, strategy can be readily applied to any protein system with known epitope sites to template a variety of bimetallic structures without the need for chemical or genetic mutations.     

In situ observation of synthesized nanoparticles in ultra-dilute aerosols via X-ray scattering

In-air epitaxy of nanostructures (Aerotaxy) has recently emerged as a viable route for fast, large-scale production. In this study, we use small-angle X-ray scattering to perform direct in-flight characterizations of the first step of this process, i.e., the engineered formation of Au and Pt aerosol nanoparticles by spark generation in a flow of N₂ gas. This represents a particular challenge for characterization because the particle density can be extremely low in controlled production. The particles produced are examined during production at operational pressures close to atmospheric conditions and exhibit a lognormal size distribution ranging from 5–100 nm. The Au and Pt particle production and detection are compared. We observe and characterize the nanoparticles at different stages of synthesis and extract the corresponding dominant physical properties, including the average particle diameter and sphericity, as influenced by particle sintering and the presence of aggregates. We observe highly sorted and sintered spherical Au nanoparticles at ultra-dilute concentrations (< 5 × 10⁵ particles/cm³) corresponding to a volume fraction below 3 × 10^–10, which is orders of magnitude below that of previously measured aerosols. We independently confirm an average particle radius of 25 nm via Guinier and Kratky plot analysis. Our study indicates that with high-intensity synchrotron beams and careful consideration of background removal, size and shape information can be obtained for extremely low particle concentrations with industrially relevant narrow size distributions.