Fermentation kinetics including product and substrate inhibitions plus biomass death: a mathematical analysis

Fermentation is generally modelled by kinetic equations giving the time evolutions for biomass, substrate, and product concentrations. Although these equations can be solved analytically in simple cases if substrate/product inhibition and biomass death are included, they are typically solved numerically. We propose an analytical treatment of the kinetic equations --including cell death and an arbitrary number of inhibitions-- in which constant yield needs not be assumed. Equations are solved in phase space, i.e. the biomass concentration is written explicitly as a function of the substrate concentration.Comment: 4 pages, 4 figure

Holographic Model at Finite Temperature with RR-chrage density

We consider a holographic model of QCD at finite temperature with nonzero chemical potentials conjugate to $R$-charge densities. A critical surface of the confinement-deconfinement phase transition is shown for five-dimensional charged black hole solution given by Behrnd, Cveti\v{c} and Sabra. On a special section of the parameter space, we find an critical curve being similar to the one expected in QCD. We calculate meson spectra and decay constants in the confinement phase of this section to see their temperature and chemical potential dependences. We could assure generalized GellMann-Oakes-Renner relation and the reduction of pion velocity near the critical point.Comment: 12 pages, 4 figures, Comments are adde

Reproducibility comparison among multiangle spectrophotometers

New color-measuring instruments known as multiangle spectrophotometers have been recently created to measure and characterize the goniochromism of special-effect pigments in many materials with a particular visual appearance (metallic, interference, pearlescent, sparkle, or glitter). These devices measure the gonioapparent color from the spectral relative reflectance factor and the L*a*b* values of the sample with different illumination and observation angles. These angles usually coincide with requirements marked in American Society for Testing and Materials (ASTM) and Deutsches Institut Für Normung standards relating to the gonioapparent color, but the results of comparisons between these instruments are still inconclusive. Therefore, the main purpose of this study is to compare several multiangle spectrophotometers at a reproducibility level according to ASTM E2214-08 guidelines. In particular, we compared two X-Rite multi-gonio spectrophotometers (MA98 and MA68II), a Datacolor multi-gonio spectrophotometer (FX10), and a BYK multi-gonio spectrophotometer (BYK-mac). These instruments share only five common measurement geometries: 45° × −30° (as 15°), 45° × −20° (as 25°), 45° × 0° (as 45°), 45° × 30° (as 75°), 45° × 65° (as 110°). Specific statistical studies were used for the reproducibility comparison, including a Hotelling test and a statistical intercomparison test to determine the confidence interval of the partial color differences ΔL*, Δa*, Δb*, and the total color difference ΔE*ab. This was conducted using a database collection of 88 metallic and pearlescent samples that were measured 20 times without the replacement of all the instruments. The final findings show that in most measurement geometries, the reproducibility differences between pairs of instruments are statistically significant, although in general, there is a better reproducibility level at certain common geometries for newer instruments (MA98 and BYK-mac). This means that these differences are due to systematic or bias errors (angle tolerances for each geometry, photometric scales, white standards, etc.), but not exclusively to random errors. However, neither of the statistical tests used is valid to discriminate and quantify the detected bias errors in this comparison between instruments.Spanish Ministry of Science and Innovation; contract grant number: DPI2008-06455-C02-02

ATIVIDADE ANTIFÚNGICA DE NANOCARREADORES CONTENDO ÓLEO DE MELALEUCA NO CRESCIMENTO DE C. ALBICANS: UM ESTUDO DO PERFIL DE INIBIÇÃO

The aim of this study was to evaluate, for the first time, the antifungal efficacy of nanocapsules suspension and nanoemulsions containing Melaleuca alternifolia essential oil (tea tree oil). Methods and results: An in vitro assay measuring antimicrobial activity against Candida albicans was performed in order to obtain an inhibition profile after 0, 5, 8, 12, 24, 48 and 72 h growth, using two different yeast concentration. The activity of oil-loaded nanostructures on C. albicans growth curve showed differences between formulations. For small concentrations of microorganism, the formulations significantly decreased yeast charge for 48 h. Moreover, the control of growth provided by the nanocapsules remained similar at all analysis times. Conclusions: The inclusion of the oil in nanocapsules proved to be more efficient in reducing and controlling C. albicans growth.O objetivo deste trabalho foi avaliar, pela primeira vez, a eficácia antifúngica de suspensões de nanocápsulas e nanoemulsões contendo óleo essencial de Melaleuca alternifolia (TTO) segundo avaliação do perfil de inibição de crescimento in vitro de Candida albicans. Métodos e resultados: A atividade antimicrobiana das formulações foi verificada frente a C. albicans a fim de se obter um perfil de inibição do crescimento após 0, 5, 8, 12, 24, 48 e 72 horas, utilizando duas concentrações da levedura. A atividade do óleo associado às nanoestruturas na curva de crescimento da levedura demonstrou diferenças entre as formulações. Para menores concentrações do microrganismo, as formulações diminuíram significantemente a carga microbiana por 48 horas. Além disso, o controle do crescimento exercido pelas nanocápsulas permaneceu similar durante todos os períodos de análise. Conclusões: A associação do óleo de melaleuca em nanocápsulas poliméricas demonstrou ser mais eficiente em reduzir e controlar o crescimento de C. albicans por até 72 horas

The Implication of Early Chromatin Changes in X Chromosome Inactivation.

During development, the precise relationships between transcription and chromatin modifications often remain unclear. We use the X chromosome inactivation (XCI) paradigm to explore the implication of chromatin changes in gene silencing. Using female mouse embryonic stem cells, we initiate XCI by inducing Xist and then monitor the temporal changes in transcription and chromatin by allele-specific profiling. This reveals histone deacetylation and H2AK119 ubiquitination as the earliest chromatin alterations during XCI. We show that HDAC3 is pre-bound on the X chromosome and that, upon Xist coating, its activity is required for efficient gene silencing. We also reveal that first PRC1-associated H2AK119Ub and then PRC2-associated H3K27me3 accumulate initially at large intergenic domains that can then spread into genes only in the context of histone deacetylation and gene silencing. Our results reveal the hierarchy of chromatin events during the initiation of XCI and identify key roles for chromatin in the early steps of transcriptional silencing

An observational study of patient characteristics associated with the mode of admission to acute stroke services in North East, England

Objective Effective provision of urgent stroke care relies upon admission to hospital by emergency ambulance and may involve pre-hospital redirection. The proportion and characteristics of patients who do not arrive by emergency ambulance and their impact on service efficiency is unclear. To assist in the planning of regional stroke services we examined the volume, characteristics and prognosis of patients according to the mode of presentation to local services. Study design and setting A prospective regional database of consecutive acute stroke admissions was conducted in North East, England between 01/09/10-30/09/11. Case ascertainment and transport mode were checked against hospital coding and ambulance dispatch databases. Results Twelve acute stroke units contributed data for a mean of 10.7 months. 2792/3131 (89%) patients received a diagnosis of stroke within 24 hours of admission: 2002 arrivals by emergency ambulance; 538 by private transport or non-emergency ambulance; 252 unknown mode. Emergency ambulance patients were older (76 vs 69 years), more likely to be from institutional care (10% vs 1%) and experiencing total anterior circulation symptoms (27% vs 6%). Thrombolysis treatment was commoner following emergency admission (11% vs 4%). However patients attending without emergency ambulance had lower inpatient mortality (2% vs 18%), a lower rate of institutionalisation (1% vs 6%) and less need for daily carers (7% vs 16%). 149/155 (96%) of highly dependent patients were admitted by emergency ambulance, but none received thrombolysis. Conclusion Presentations of new stroke without emergency ambulance involvement were not unusual but were associated with a better outcome due to younger age, milder neurological impairment and lower levels of pre-stroke dependency. Most patients with a high level of pre-stroke dependency arrived by emergency ambulance but did not receive thrombolysis. It is important to be aware of easily identifiable demographic groups that differ in their potential to gain from different service configurations

Nanostructured systems containing an essential oil: protection against volatilization

The goal of this study was to evaluate the feasibility of preparing nanocapsules and nanoemulsions using tea tree oil as oily phase aiming to protect its volatilization. The nanostructures presented nanometric mean size (160-220 nm) with a polydispersity index below 0.25 and negative zeta potential. The pH values were 6.43 ± 0.37 and 5.98 ± 0.00 for nanoemulsions and nanocapsules, respectively. The oil content after preparation was 96%. The inclusion of tea tree oil in nanocapsules showed higher protection against volatilization. The analysis of mean size and polydispersity index of formulations presented no significant alteration during the storage time

Experimental Quantum Hamiltonian Learning

Efficiently characterising quantum systems, verifying operations of quantum devices and validating underpinning physical models, are central challenges for the development of quantum technologies and for our continued understanding of foundational physics. Machine-learning enhanced by quantum simulators has been proposed as a route to improve the computational cost of performing these studies. Here we interface two different quantum systems through a classical channel - a silicon-photonics quantum simulator and an electron spin in a diamond nitrogen-vacancy centre - and use the former to learn the latter's Hamiltonian via Bayesian inference. We learn the salient Hamiltonian parameter with an uncertainty of approximately $10^{-5}$. Furthermore, an observed saturation in the learning algorithm suggests deficiencies in the underlying Hamiltonian model, which we exploit to further improve the model itself. We go on to implement an interactive version of the protocol and experimentally show its ability to characterise the operation of the quantum photonic device. This work demonstrates powerful new quantum-enhanced techniques for investigating foundational physical models and characterising quantum technologies

Desenvolvimento tecnológico de hidrogéis a partir de nanoemulsão contendo clotrimazol em associação com o óleo de melaleuca

O clotrimazol é um antifúngico imidazólico de uso tópico indicado para o tratamento de micoses superficiais, principalmente aquelas causadas por leveduras do gênero Candida. O óleo essencial de Melaleuca alternifolia (óleo de melaleuca) apresenta conhecidas propriedades anti-inflamatória, antiviral, antibacteriana e antifúngica. No presente trabalho, nanoemulsões contendo clotrimazol e o óleo de melaleuca foram preparadas, a fim de obter uma forma farmacêutica semissólida de base aquosa contendo o nanocarreador proposto. As nanoemulsões foram preparadas pelo método de emulsificação espontânea e apresentaram tamanho manométrico (150 a 380 nm), baixo índice de polidispersão (<0,13), potencial zeta negativo e teor de fármaco próximo ao teórico (1,02 ± 0,92 mg/mL), as quais se mantiveram estáveis após 30 dias de armazenamento a temperatura ambiente. Na avaliação da atividade antifúngica frente à leveduras de C. albicans, o fármaco manteve sua atividade. Posteriormente, as nanoemulsões foram incorporadas em géis de Carbopol® Ultrez e estes foram avaliados, os quais apresentaram características adequadas para aplicação tópica: pH levemente ácido (6,2 a 6,5), comportamento de fluxo não-newtoniano e plástico e teor de fármaco próximo a 100%, demonstrando a viabilidade tecnológica de sua preparação. Além disso, o hidrogel contendo o fármaco nanoestruturado apresentou um controle maior de liberação do clotrimazol quando comparado ao hidrogel contendo o fármaco não associado

Binary AMD Circuits from Secure Multiparty Computation

An AMD circuit over a finite field $\mathbb F$ is a randomized arithmetic circuit that offers the ``best possible protection\u27\u27 against additive attacks. That is, the effect of every additive attack that may blindly add a (possibly different) element of $\mathbb F$ to every internal wire of the circuit can be simulated by an ideal attack that applies only to the inputs and outputs. Genkin et al. (STOC 2014, Crypto 2015) introduced AMD circuits as a means for protecting MPC protocols against active attacks, and showed that every arithmetic circuit C over F can be transformed into an equivalent AMD circuit of size $O(|C|)$ with $O(1/|\mathbb F|)$ simulation error. However, for the case of the binary field $\mathbb F=\mathbb F_2$, their constructions relied on a tamper-proof output decoder and could only realize a weaker notion of security. We obtain the first constructions of fully secure binary AMD circuits. Given a boolean circuit $C$ and a statistical security parameter $s$, we construct an equivalent binary AMD circuit $C\u27$ of size $|C|*polylog(|C|,s)$ (ignoring lower order additive terms) with $2^{-s}$ simulation error. That is, the effect of toggling an arbitrary subset of wires can be simulated by toggling only input and output wires. Our construction combines in a general way two types of ``simple\u27\u27 honest-majority MPC protocols: protocols that only offer security against passive adversaries, and protocols that only offer correctness against active adversaries. As a corollary, we get a conceptually new technique for constructing active-secure two-party protocols in the OT-hybrid model, and reduce the open question of obtaining such protocols with constant computational overhead to a similar question in these simpler MPC models