8,594 research outputs found
Novel insights on pink discoloration in cheese: The case of Pecorino Toscano
Pink discoloration in cheese has been the subject of wide research, but the basis for this phenomenon remains elusive. This defect impacts a wide range of ripened cheeses, resulting in the rejection of cheese and a consequent economic loss for dairy industries. As multiple causes for pink discoloration have been reported for different cheeses in the literature, the aim of this research was to investigate the cause of a pink discoloration found on Pecorino Toscano cheese rind. The results of microbiological analysis revealed the presence of high microbial counts associated to the rind and the nearest inner part. Strains isolated from the coloured part were mainly identified as Serratia liquefaciens, suggesting that an environmental contamination of the cheese rind by this species could be the cause of the observed defect and expanding the knowledge related to pink discoloration in cheeses
Direct Measurement of the Reduced Scattering Coefficient by a Calibrated Random Laser Sensor
The research in optical sensors has been largely encouraged by the demand for low-cost and less or non-invasive new detection strategies. The invention of the random laser has opened a new frontier in optics, providing also the opportunity to explore new possibilities in the field of sensing, besides several different and peculiar phenomena. The main advantage in exploiting the physical principle of the random laser in optical sensors is due to the presence of the stimulated emission mechanism, which allows amplification and spectral modification of the signal. Here, we present a step forward in the exploitation of this optical phenomenon by a revisitation of a previous experimental setup, as well as the measurement method, in particular to mitigate the instability of the results due to shot-to-shot pump energy fluctuations. In particular, the main novelties of the setup are the use of optical fibers, a reference sensor, and a peristaltic pump. These improvements are devoted to: eliminating optical beam alignment issues; improving portability; mitigating the variation in pump energy and gain medium performances over time; realizing an easy and rapid change of the sensed medium. The results showed that such a setup can be considered a prototype for a portable device for directly measuring the scattering of liquid samples, without resorting to complicated numerical or analytic inversion procedures of the measured data, once the suitable calibration of the system is performed
MicroRNA-222 regulates muscle alternative splicing through Rbm24 during differentiation of skeletal muscle cells
A number of microRNAs have been shown to regulate skeletal muscle development and differentiation. MicroRNA-222 is downregulated during myogenic differentiation and its overexpression leads to alteration of muscle differentiation process and specialized structures. By using RNA-induced silencing complex (RISC) pulldown followed by RNA sequencing, combined with in silico microRNA target prediction, we have identified two new targets of microRNA-222 involved in the regulation of myogenic differentiation, Ahnak and Rbm24. Specifically, the RNA-binding protein Rbm24 is a major regulator of muscle-specific alternative splicing and its downregulation by microRNA-222 results in defective exon inclusion impairing the production of muscle-specific isoforms of Coro6, Fxr1 and NACA transcripts. Reconstitution of normal levels of Rbm24 in cells overexpressing microRNA-222 rescues muscle-specific splicing. In conclusion, we have identified a new function of microRNA-222 leading to alteration of myogenic differentiation at the level of alternative splicing, and we provide evidence that this effect is mediated by Rbm24 protei
Holographic renormalization and supersymmetry
Holographic renormalization is a systematic procedure for regulating
divergences in observables in asymptotically locally AdS spacetimes. For dual
boundary field theories which are supersymmetric it is natural to ask whether
this defines a supersymmetric renormalization scheme. Recent results in
localization have brought this question into sharp focus: rigid supersymmetry
on a curved boundary requires specific geometric structures, and general
arguments imply that BPS observables, such as the partition function, are
invariant under certain deformations of these structures. One can then ask if
the dual holographic observables are similarly invariant. We study this
question in minimal N = 2 gauged supergravity in four and five dimensions. In
four dimensions we show that holographic renormalization precisely reproduces
the expected field theory results. In five dimensions we find that no choice of
standard holographic counterterms is compatible with supersymmetry, which leads
us to introduce novel finite boundary terms. For a class of solutions
satisfying certain topological assumptions we provide some independent tests of
these new boundary terms, in particular showing that they reproduce the
expected VEVs of conserved charges.Comment: 70 pages; corrected typo
A Note on Einstein Sasaki Metrics in D \ge 7
In this paper, we obtain new non-singular Einstein-Sasaki spaces in
dimensions D\ge 7. The local construction involves taking a circle bundle over
a (D-1)-dimensional Einstein-Kahler metric that is itself constructed as a
complex line bundle over a product of Einstein-Kahler spaces. In general the
resulting Einstein-Sasaki spaces are singular, but if parameters in the local
solutions satisfy appropriate rationality conditions, the metrics extend
smoothly onto complete and non-singular compact manifolds.Comment: Latex, 13 page
Multicomutation flow system for spectrophometric total amido acids determination in plant material.
To identify lhe nitrogen transportation forms and attain the control mechanism, the amount of free amino acids in different parts of lhe plant has to be determined. An automatic, fast and reliable procedure multicomutated flow system {1] has been developed for spectrophotometric analysis of totalamino acids in plant material. The method is suitable for routine analysis for a large number of samples of plant material. The flow manifold was designed with computer-controlled three-way solenoid valves for independent handling of sample and reagent solutions and a data acquisition system from a spectrophotometer, employed for signal measurements. The software for system control was performed bya program with use of a LabView platform INationallntruments) [2]. The detection reaction was based on the complexation of amino functional groups of amino acids by ninhydrin. It reacts with free a-amino groups, producing lhe colored ninhydrin chromophore called Ruhemann's purple IRP) IAm". = 570 nm; E = 22 000) [3]. The proposed detection system shows a linear range concentration up to 2.0 X 10-3 mal L-I with coefficient of variation of 1.1% (n = 101. Detection limits were estimated as 2.8 x 10-3 mal L-I at 99.7% confidence level for total amino acids. and a mean sampling rale of 30 determinations per hour was achieved
Multicommuted flow system for the determination of glucose in animal blood serum exploiting enzymatic reaction and chemiluminescence detection
An automatic flow procedure based on multicommutation dedicated for the determination of glucose in animal blood serum using glucose oxidase with chemiluminescence detection is described. The flow manifold consisted of a set of three-way solenoid valves assembled to implement multicommutation. A microcomputer furnished with an electronic interface and software written in Quick BASIC 4.5 controlled the manifold and performed data acquisition. Glucose oxidase was immobilized on porous silica beads (glass aminopropyl) and packed in a minicolumn (15 Ă 5 mm). The procedure was based on the enzymatic degradation of glucose, producing hydrogen peroxide, which oxidized luminol in the presence of hexacyanoferrate(III), causing the chemiluminescence. The system was tested by analysing a set of serum animal samples without previous treatment. Results were in agreement with those obtained with the conventional method (LABTEST Kit) at the 95% confidence level. The detection limit and variation coefficient were estimated as 12.0 mg l(â1) (99.7% confidence level) and 3.5% (n = 20), respectively. The sampling rate was about 60 determinations h(â1) with sample concentrations ranging from 50 to 600 mg l(â1) glucose. The consumptions of serum sample, hexacyanoferrate(III) and luminol were 46 ÎŒl, 10.0 mg and 0.2 mg/determination, respectively
Occurrence of grapevine virus A (GVA) and other closteroviruses in Tunisian grapevines affected by leafroll disease
Vorkommen von Grapevine-Virus A (GVA) und anderen Closteroviren in blattrollkranken tunesischen RebenReben, die aus den Hauptweinbaugebieten Tunesiens stammten, wurden auf die Anwesenheit von Closteroviren hin ĂŒberprĂŒft. WĂ€hrend in keiner der symptomfreien Reben Viruspartikel entdeckt wurden, enthielten alle Reben mit Blattrollsymptomen - auĂer zweien - Closteroviruspartikel, die durch IEM (immune electron microscopy) in konzentrierten Blattextrakten oder unmittelbar in Rohsaft durch ISEM (immunosorbent electron microscopy) identifiziert wurden. Alle vier derzeit bekannten Closteroviren (GClV-1, GClV-2, GClV-3 und GVA) waren, meistens im Gemisch, in Reben mit Blattrollsymptomen vorhanden. GClV-3 und GVA wurden in 77 bzw. 50 % der geprĂŒften Reben entdeckt. Ein tunesisches Isolat von GVA, das durch Planococcus citri auf krautige Testpflanzen ĂŒbertragen wurde, unterschied sich in biologischer Hinsicht, aber nicht in den charakteristischen physikalisch-chemischen und serologischen Eigenschaften von zwei italienischen Isolaten desselben Virus
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