Modelling the effect of combined antimicrobials: A base model for multiple-hurdles

Combining antimicrobials to reduce microbial growth and to combat the potential impact of antimicrobial resistance is an important subject both in foods and in pharmaceutics. Modelling of combined treatments designed to reduce or eliminate microbial contamination in foods (microbiological predictive modelling) has become commonplace. Two main reference models are used to analyse mixtures: the Bliss Independence and the Loewe reference models (LRM). By using optical density to analyse the growth of Aeromonas hydrophila, Cronobacter sakazakii and Escherichia coli in combined NaCl/NaCl (a mock combination experiment) and combined NaCl/KCl experiments, previous models for combined antimicrobials in foods, based on the Bliss approach, were shown to be inconsistent and that models based on the LRM more applicable. The LRM was shown, however, to be valid only in the specific cases where the concentration exponents of all components in a mixture were identical. This is assured for a mock combination experiment but not for a true mixture. This, essentially, invalidates the LRM as a general reference model. A new model, based on the LRM but allowing for mixed exponents, was used to analyse the combined inhibition data, and concluded that the NaCl/KCl system gave the additive effect expected from literature studies. This study suggests the need to revise current models used to analyse combined effects

Temperature Effects on Global DNA Methylation and Gene Expression During Larval development in the European Sea Bass

1 page• Fish represent good animal models for the purposes of identifying persistent epigenetic marks which arise from different early developmental environments and which correlate with relevant biological processes later in life. • In sexually differentiated one-year-old European sea bass (Dicentrarchus labrax), the methylation levels of the promoter of gonadal aromatase (cyp19a), which converts androgens into estrogens, have been shown to increase in females after exposure of larvae to high temperature during the thermosensitive period (TSP) [1]. • The goal of this study was to determine whether temperature treatments during different time intervals within the TSP are able to alter the genome-wide patterns of DNA methylation and the expression of specific genes.Supported by grant AGL2010-15939 (“Epigen-Aqua”) to FPPeer Reviewe

Acupuncture Reduces Pain in Patients with Temporomandibular Joint Disorders. A Systematic Review

Aims: Acupuncture is an alternative method used to treat patients with Temporomandibular joint disorders (TMD). However, it still has not been well established, as an effective and safe option, in literature. This systematic review aims to investigate: (a) the quality of the methodology used in previous Randomized Controlled and Clinical Trials, concerning the effectiveness of acupuncture, in reducing pain, in patients with TMD, (b) the effectiveness of acupuncture, in reducing pain, in patients with TMD. Method: Electronic databases were investigated to identify available Randomized Controlled and Clinical Trials concerning the effectiveness of acupuncture in reducing pain in patients with TMD; Specific criteria were used to select eligible studies; the quality of studies was assessed using the PEDro scale; an evaluation of differences was performed between the qualified studies. Results: A total of ten Randomized Controlled and Clinical trials were included in this systematic review. The methodology used in most studies was determined to be low to moderate. Nine out of ten studies showed statistically significant results in reducing pain. However, acupuncture was not more effective than other therapeutic methods used in most of the studies. Only 2/10 studies revealed that acupuncture was more effective, when compared to other methods. Acupuncture reduced pain faster and the results lasted up to one month, when compared to other methods. Conclusion: Acupuncture is an effective method, in relieving pain, in patients with TMD. There is, however, need for more, qualitatively improved studies in order to verify acupunctures effects in patients with TMD

Novel optical fibres for on-chip optical tweezing and bio-applications

Optical trapping of a single cell is a technique widely used in many scientific sectors due to the benefits of isolating and examining a single cell in isolation. Studies that use a conventional microscope-based tweezing system demonstrate optical trapping based on strongly focused laser light delivered through a high Numerical Aperture objective. However, this approach poses restrictions to the range of the applications of the tweezing system due to the use of the imaging optics for tweezing beam delivery. To overcome these restrictions, optical fibre-based systems to optically trap a single cell have been studied. In this thesis, an optical tweezing system based on machined four core optical fibres has been developed and applied to a variety of cells. Mirrors, with an angle slightly higher than the critical angle for the fibre to medium interface, have been fabricated on the end of a four-core fibre, to alter the propagation of the laser beam exiting the four cores. The four beams are directed to overlap, and the optical fibre trap acts in a manner similar to a conventional optical tweezer. The multicore fibre (MCF) trap is composed of four diverging beams which overlap to form a trapping volume, as opposed to the trapping volume of an optical tweezer which is formed by tightly focusing a single beam via a high numerical aperture objective lens. It is shown that micron-scale particles can be optically trapped in this overlap region of the MCF trap. Optical trapping of yeast cells, and also a wider range of cells such as red blood cells, U87 cells and mouse embryonic stem cells is reported in this thesis. The optical trapping system has been used also below a Raman microscope. This demonstrates the ability to trap cells under an analytical microscope without modifying the microscope optics, and to capture the Raman spectra from single trapped cells. The work presented in the thesis demonstrates a flexible system of small dimension, to trap cells for use under a wide range of microscopes, circumventing the need to focus a trapping beam through a high numerical aperture objective lens. The trap has been characterised by measuring the maximum trapping velocities and trap strengths, which are comparable to conventional optical tweezers. The trapping system has also been used to investigate alternative optical manipulation of 'special' particles, such as hollow glass spheres, that cannot be optically trapped with a conventional optical tweezers system due to their low refractive index. The machined multicore fibre uses the region between the beam overlap area and the fibre end face, to hold these low refractive index particles in place. The primary objectives of the work described in this thesis were to optimise the FIB fabrication of the mirrors on the MCF trap, build a robust, portable system capable of cell trapping and manipulation under different analytical microscopes, characterise the beam propagation characteristics, demonstrate stable trapping of some exemplar cell types, and compare the trap strength with conventional optical tweezers

An axiomatization of verdict equivalence over regular monitors

Monitors are a key tool in the field of runtime verification, where they are used to check for system properties by analysing execution traces generated by processes. Work on runtime monitoring carried out in a series of papers by Aceto et al. has specified monitors using a variation on the regular fragment of Milner's CCS and studied two trace-based notions of equivalence over monitors, namely verdict and $\omega$-verdict equivalence. This article is devoted to the study of the equational logic of monitors modulo those two notions of equivalence. It presents complete equational axiomatizations of verdict and $\omega$-verdict equivalence for closed and open terms over recursion-free monitors.Comment: Preprint submitted to Journal of logical and algebraic methods in programing 202

Syntactic approaches to negative results in process algebras and modal logics

Concurrency as a phenomenon is observed in most of the current computer science trends. However the inherent complexity of analyzing the behavior of such a system is incremented due to the many different models of concurrency, the variety of applications and architectures, as well as the wide spectrum of specification languages and demanded correctness criteria. For the scope of this thesis we focus on state based models of concurrent computation, and on modal logics as specification languages. First we study syntactically the process algebras that describe several different concurrent behaviors, by analyzing their equational theories. Here, we use well-established techniques from the equational logic of processes to older and newer setups, and then transition to the use of more general and novel methods for the syntactical analysis of models of concurrent programs and specification languages. Our main contributions are several positive and negative axiomatizability results over various process algebraic languages and equivalences, along with some complexity results over the satisfiability of multi-agent modal logic with recursion, as a specification language.Samhliða sem fyrirbæri sést í flestum núverandi tölvunarfræði stefnur. Hins vegar er eðlislægt flókið að greina hegðun slíks kerfis- tem er aukið vegna margra mismunandi gerða samhliða, fjölbreytileikans af forritum og arkitektúr, svo og breitt svið forskrifta mælikvarða og kröfðust réttmætisviðmiða. Fyrir umfang þessarar ritgerðar leggjum við áherslu á ástandsbundin líkön af samhliða útreikningum og á formlegum rökfræði sem forskrift tungumálum. Fyrst skoðum við setningafræðilega ferlialgebrurnar sem lýsa nokkrum mismunandi samhliða hegðun, með því að greina jöfnukenningar þeirra. Hér notum við rótgróin tækni mynda jöfnunarrökfræði ferla til eldri og nýrri uppsetningar, og síðan umskipti yfir í notkun almennari og nýrra aðferða fyrir setningafræðileg greining á líkönum samhliða forrita og forskriftartungumála. Helstu framlög okkar eru nokkrar jákvæðar og neikvæðar niðurstöður um axiomatizability yfir ýmis ferli algebrumál og jafngildi, ásamt nokkrum samSveigjanleiki leiðir af því að fullnægjanleiki fjölþátta formrökfræði með endurkomu, sem a forskrift tungumál.RANNIS: `Open Problems in the Equational Logic of Processes’ (OPEL) (grant No 196050-051) Reykjavik University research fund: `Runtime and Equational Verification of Concurrent Programs' (ReVoCoP) (grant No 222021

Tissue biochemical diversity of 20 gooseberry cultivars and the effect of ethylene supplementation on postharvest life

The European gooseberry (Ribes uva-crispa) is still an understudied crop with limited data available on its biochemical profile and postharvest life. A variety of polyphenols were detected in the skin and flesh of 20 gooseberry cvs, representing mainly flavonol glycosides, anthocyanins and flavan-3-ols. In contrast, gooseberry seeds were for the first time characterised by the presence of considerable amounts of hydroxycinnamic acid glycosides tentatively identified by UPLC-QToF/MS. All cvs examined represented a good source of vitamin C while being low in sugar. Furthermore, the postharvest stability of bioactives was explored by supplementation of exogenous ethylene in air at 5 °C. Results suggest a low sensitivity of gooseberries to ethylene. The overall quality of gooseberries remained stable over two weeks, showing potential for extended bioactive life