The Challenges of O2 Detection in Biological Fluids: Classical Methods and Translation to Clinical Applications

Dissolved oxygen (DO) is deeply involved in preserving the life of cellular tissues and human beings due to its key role in cellular metabolism: its alterations may reflect important pathophysiological conditions. DO levels are measured to identify pathological conditions, explain pathophysiological mechanisms, and monitor the efficacy of therapeutic approaches. This is particularly relevant when the measurements are performed in vivo but also in contexts where a variety of biological and synthetic media are used, such as ex vivo organ perfusion. A reliable measurement of medium oxygenation ensures a high-quality process. It is crucial to provide a high-accuracy, real-time method for DO quantification, which could be robust towards different medium compositions and temperatures. In fact, biological fluids and synthetic clinical fluids represent a challenging environment where DO interacts with various compounds and can change continuously and dynamically, and further precaution is needed to obtain reliable results. This study aims to present and discuss the main oxygen detection and quantification methods, focusing on the technical needs for their translation to clinical practice. Firstly, we resumed all the main methodologies and advancements concerning dissolved oxygen determination. After identifying the main groups of all the available techniques for DO sensing based on their mechanisms and applicability, we focused on transferring the most promising approaches to a clinical in vivo/ex vivo setting.     

Single-Tear Proteomics: A Feasible Approach to Precision Medicine

Lacrimal fluid is an attractive source of noninvasive biomarkers, the main limitation being the small sample amounts typically collected. Advanced analytical methods to allow for proteomics profiling from a few microliters are needed to develop innovative biomarkers, with attractive perspectives of applications to precision medicine. This work describes an effective, analytical pipeline for single-tear analysis by ultrahigh-resolution, shotgun proteomics from 23 healthy human volunteers, leading to high-confidence identification of a total of 890 proteins. Highly reproducible quantification was achieved by either peak intensity, peak area, or spectral counting. Hierarchical clustering revealed a stratification of females vs. males that did not emerge from previous studies on pooled samples. Two subjects were monitored weekly over 3 weeks. The samples clustered by withdrawal time of day (morning vs. afternoon) but not by follow-up week, with elevated levels of components of the immune system in the morning samples. This study demonstrates feasibility of single-tear quantitative proteomics, envisaging contributions of this unconventional body fluid to individualized approaches in biomedicine.     

Effect of polymerization conditions on the microstructure of a liquid crystalline copolyester

The melt polycondensation of mixtures of sebacic acid (S), 4,4′‐diacetoxybiphenyl (B), and 4‐acetoxybenzoic acid (H), carried out for the synthesis of semiflexible liquid–crystalline copolyesters referred to as SBH 1 : 1 : x, has been studied with the aim of clarifying the effect of the reaction conditions on the microstructure and the thermal properties of the products. It has been shown that the segregation of a liquid–crystalline phase within the polymerizing mixture, coupled with the thermodynamic tendency of the two phases to undergo compositional differentiation as polymerization proceeds, is responsible for the formation of blocky, rather than ideally random, copolyesters with poor processibility, when the mole ratio of H to the other two monomers is higher than x ≈ 1.90. The results of this study have shown that this unwanted effect can be considerably limited by carrying out the polycondensation at a relatively high temperature from the very beginning, rather than by the standard technique involving progressive heating of the reaction mixture, thus allowing the production of SBH copolyesters with a higher degree of aromaticity. The results are discussed in terms of the relative rates of the condensation reactions, which are responsible for chain growth, and of the concurrent acidolysis and esterolysis reactions leading to copolyester sequence reorganization. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 141–150, 2000     

Phenolic Chemistry of Coast Live Oak Response to <Emphasis Type="Italic">Phytophthora ramorum</Emphasis> Infection

Since the mid 1990s, Phytophthora ramorum has been responsible for the widespread mortality of tanoaks, as well as several oak species throughout California and Oregon forests. However, not all trees die, even in areas with high disease pressure, suggesting that some trees may be resistant to the pathogen. In this study, the chemical basis of host resistance was investigated. Three field experiments were carried out in California between December 2004 and September 2005. The levels of nine phenolic compounds (gallic acid, catechin, tyrosol, a tyrosol derivative, ellagic acid, and four ellagic acid derivatives) extracted from the phloem of trees that had been either artificially inoculated with P. ramorum or trees putatively infected with P. ramorum (based on canker symptoms) were quantified by high-performance liquid chromatography (HPLC). Significant differences in phenolic profiles were found between phloem sampled from the active margins of cankers, healthy phloem from asymptomatic trees, and phloem sampled 60 cm away from canker sites, although the magnitude and direction of the responses was not consistent across all experiments. Concentrations of gallic acid, tyrosol, and ellagic acid showed the greatest differences in these different tissues, but varied considerably across treatments. Gallic acid and tyrosol were tested in in vitro bioassays and showed strong dose-dependent inhibitory effects against P. ramorum, P. cinnamomi, P. citricola, and P. citrophthora. These results suggest that phloem chemistry varies in response to pathogen infection in California coast live oak populations and that changes in phloem chemistry may be related to apparently resistant phenotypes observed in the field. Frances S. Ockels and Alieta Eyles contributed equally to the paper     

Verification in loosely synchronous queue-connected discrete timed automata

We look at a model of a queue system that consists of the following components:

1. Two discrete timed automata W (the “writer”) and R (“the reader”).

2. One unrestricted queue that can be used to send messages from W to R. There is no bound on the length of the queue.

W and R do not share a global clock and operate in a loosely synchronous way. That is, the absolute value of the difference between the local time of W and the local time of R is always bounded by a positive constant. We show that the binary reachability for these systems is effectively computable, and this result is generalized to the case when there are two queues (one from W to R and the other from R to W) that operate in half-duplex. We then present some properties (e.g., safety, invariance, etc.) that can be verified for loosely synchronous queue-connected discrete timed automata and give an example of a system composed of a sensor and a controller that is verifiable using our results.     

Mass spectrometry-based tear proteomics for noninvasive biomarker discovery

The lacrimal film has attracted increasing interest in the last decades as a potential source of biomarkers of physiopathological states, due to its accessibility, moderate complexity, and responsiveness to ocular and systemic diseases. High-performance liquid chromatography-mass spectrometry (LC-MS) has led to effective approaches to tear proteomics, despite the intrinsic limitations in sample amounts. This review focuses on the recent progress in strategy and technology, with an emphasis on the potential for personalized medicine. After an introduction on lacrimal-film composition, examples of applications to biomarker discovery are discussed, comparing approaches based on pooled-sample and single-tear analysis. Then, the most critical steps of the experimental pipeline, that is, tear collection, sample fractionation, and LC-MS implementation, are discussed with reference to proteome-coverage optimization. Advantages and challenges of the alternative procedures are highlighted. Despite the still limited number of studies, tear quantitative proteomics, including single-tear investigation, could offer unique contributions to the identification of low-invasiveness, sustained-accessibility biomarkers, and to the development of personalized approaches to therapy and diagnosis.     

Nanogap structures for molecular nanoelectronics

This study is focused on the realization of nanodevices for nano and molecular electronics, based on molecular interactions in a metal-molecule-metal (M-M-M) structure. In an M-M-M system, the electronic function is a property of the structure and can be characterized through I/V measurements. The contact between the metals and the molecule was obtained by gold nanogaps (with a dimension of less than 10 nm), produced with the electromigration technique. The nanogap fabrication was controlled by a custom hardware and the related software system. The studies were carried out through experiments and simulations of organic molecules, in particular oligothiophenes.     

Manufacture of ITER feeder sample conductors

The ITER feeders are the components that connect the ITER magnet systems located inside the main cryostat to the cryogenics, power-supply and control system interfaces outside the cryostat. The feeder busbars rely on the Cable-In-Conduit Conductor (CICC) design concept as all the conductors for the ITER magnet systems. There are two types of busbars for the feeder systems. One is the Main Busbar (MB) for the TF, CS and PF feeders, and the other is the Corrector Busbar (CB) for the CC feeders. The busbar cable is wound from multiple stage sub-cables made with Cu and superconducting strands. The superconducting material is NbTi for the busbar strands of all feeder systems. All Feeder conductors are provided by China. The R&D programs are needed to acquire knowledge on the behavior of such conductors.Since the conductors are new, some full size copper dummy conductors have been produced for the testing of the cabling parameters, definition of automatic TIG welding of seamless jacket section, elaboration of cable insertion and compaction. Then, two short qualification conductor samples (MB and CB) are prepared in ASIPP, and NbTi advanced strands are produced by Western Superconductor Technology (WST).The details of manufacturing procedures for Feeder conductor samples will be described in this paper.     

Structure–activity relationships of resveratrol and derivatives in breast cancer cells

Resveratrol (RSV) is classified as a phytoestrogen due to its ability to interact with estrogen receptors (ERs). We assessed structure–activity relationships of RSV and the analogs 4,4′‐dihydroxystilbene (4,4′‐DHS), 3,5‐dihydroxystilbene (3,5‐DHS), 3,4′‐dihydroxystilbene (3,4′‐DHS), 4‐hydroxystilbene (4‐HS) using as model systems the ERα‐positive and negative MCF7 and SkBr3 breast cancer cells, respectively. In binding assays and transfection experiments RSV and the analogs showed the following order of agonism for ERα: 3,4′‐DHS > 4,4′‐DHS > 4‐HS > RSV, while 3,5‐DHS did not elicit any ligand properties. Computational docking analysis and real‐time PCR revealed for each analog a distinct ERα binding orientation and estrogen target gene expression profile. Interestingly, the aforementioned order of ligand activity was confirmed in proliferation assays which also showed the lack of growth stimulation by 3,5‐DHS. Our data suggest that subtle changes in the structure of the RSV derivatives examined may be responsible for the different ERα‐mediated biological responses observed in estrogen‐sensitive cancer cells.     

Experimental investigation of direct internal reforming of biogas in solid oxide fuel cells

This work investigates the behaviour of planar solid oxide fuel cells (SOFCs) fed by two different fuel mixtures that simulate biogases coming from anaerobic digestion. The fuel mixtures are namely bio-methane and bio-hydrogen. The first composition is the conventional one, where a biological process of fermentation is carried out to produce a gas that contains a mixture of methane and carbon dioxide with traces of H₂S and other organic sulphur compounds. The second mixture is representative of a biogas produced through a novel routine: a particular pre-treatment of the bacteria inoculum (generally clostridia bacteria) is performed in order to inhibit the methanogenic step in the fermentation process, such that bio-hydrogen is produced as the only effluent of the digester (a mixture of H₂/CO₂, with no traces of methane).