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1.
Nature ; 623(7985): 157-166, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37853118

RESUMO

Immunotherapy failures can result from the highly suppressive tumour microenvironment that characterizes aggressive forms of cancer such as recurrent glioblastoma (rGBM)1,2. Here we report the results of a first-in-human phase I trial in 41 patients with rGBM who were injected with CAN-3110-an oncolytic herpes virus (oHSV)3. In contrast to other clinical oHSVs, CAN-3110 retains the viral neurovirulence ICP34.5 gene transcribed by a nestin promoter; nestin is overexpressed in GBM and other invasive tumours, but not in the adult brain or healthy differentiated tissue4. These modifications confer CAN-3110 with preferential tumour replication. No dose-limiting toxicities were encountered. Positive HSV1 serology was significantly associated with both improved survival and clearance of CAN-3110 from injected tumours. Survival after treatment, particularly in individuals seropositive for HSV1, was significantly associated with (1) changes in tumour/PBMC T cell counts and clonal diversity, (2) peripheral expansion/contraction of specific T cell clonotypes; and (3) tumour transcriptomic signatures of immune activation. These results provide human validation that intralesional oHSV treatment enhances anticancer immune responses even in immunosuppressive tumour microenvironments, particularly in individuals with cognate serology to the injected virus. This provides a biological rationale for use of this oncolytic modality in cancers that are otherwise unresponsive to immunotherapy (ClinicalTrials.gov: NCT03152318 ).


Assuntos
Neoplasias Encefálicas , Glioblastoma , Herpesvirus Humano 1 , Terapia Viral Oncolítica , Vírus Oncolíticos , Humanos , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/patologia , Glioblastoma/imunologia , Glioblastoma/patologia , Nestina/genética , Terapia Viral Oncolítica/efeitos adversos , Vírus Oncolíticos/genética , Vírus Oncolíticos/imunologia , Vírus Oncolíticos/fisiologia , Reprodutibilidade dos Testes , Análise de Sobrevida , Linfócitos T/citologia , Linfócitos T/imunologia , Resultado do Tratamento , Microambiente Tumoral/imunologia , Herpesvirus Humano 1/genética , Herpesvirus Humano 1/imunologia , Herpesvirus Humano 1/fisiologia
2.
Microsc Microanal ; 30(1): 151-159, 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38302194

RESUMO

Analysis of bone marrow aspirates (BMAs) is an essential step in the diagnosis of hematological disorders. This analysis is usually performed based on a visual examination of samples under a conventional optical microscope, which involves a labor-intensive process, limited by clinical experience and subject to high observer variability. In this work, we present a comprehensive digital microscopy system that enables BMA analysis for cell type counting and differentiation in an efficient and objective manner. This system not only provides an accessible and simple method to digitize, store, and analyze BMA samples remotely but is also supported by an Artificial Intelligence (AI) pipeline that accelerates the differential cell counting process and reduces interobserver variability. It has been designed to integrate AI algorithms with the daily clinical routine and can be used in any regular hospital workflow.


Assuntos
Inteligência Artificial , Doenças Hematológicas , Humanos , Medula Óssea , Microscopia , Doenças Hematológicas/diagnóstico , Algoritmos
3.
Stem Cells ; 40(3): 273-289, 2022 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-35356986

RESUMO

Insulin-like growth factor I (IGF-1) has been implicated in breast cancer due to its mitogenic and anti-apoptotic effects. Despite substantial research on the role of IGF-1 in tumor progression, the relationship of IGF-1 to tissue stem cells, particularly in mammary tissue, and the resulting tumor susceptibility has not been elucidated. Previous studies with the BK5.IGF-1 transgenic (Tg) mouse model reveals that IGF-1 does not act as a classical, post-carcinogen tumor promoter in the mammary gland. Pre-pubertal Tg mammary glands display increased numbers and enlarged sizes of terminal end buds, a niche for mammary stem cells (MaSCs). Here we show that MaSCs from both wild-type (WT) and Tg mice expressed IGF-1R and that overexpression of Tg IGF-1 increased numbers of MaSCs by undergoing symmetric division, resulting in an expansion of the MaSC and luminal progenitor (LP) compartments in pre-pubertal female mice. This expansion was maintained post-pubertally and validated by mammosphere assays in vitro and transplantation assays in vivo. The addition of recombinant IGF-1 promoted, and IGF-1R downstream inhibitors decreased mammosphere formation. Single-cell transcriptomic profiles generated from 2 related platforms reveal that IGF-1 stimulated quiescent MaSCs to enter the cell cycle and increased their expression of genes involved in proliferation, plasticity, tumorigenesis, invasion, and metastasis. This study identifies a novel, pro-tumorigenic mechanism, where IGF-1 increases the number of transformation-susceptible carcinogen targets during the early stages of mammary tissue development, and "primes" their gene expression profiles for transformation.


Assuntos
Fator de Crescimento Insulin-Like I , Glândulas Mamárias Animais , Animais , Proliferação de Células , Feminino , Humanos , Fator de Crescimento Insulin-Like I/metabolismo , Camundongos , Camundongos Transgênicos , Células-Tronco/metabolismo
4.
J Chem Phys ; 159(3)2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37477217

RESUMO

The structural properties of confined single-file hard-disk fluids are studied analytically by means of a mapping of the original system onto a one-dimensional mixture of non-additive hard rods, the mapping being exact in the polydisperse limit. Standard statistical-mechanical results are used as a starting point to derive thermodynamic and structural properties of the one-dimensional mixture, where the condition that all particles have the same chemical potential must be taken into account. Analytical results are then provided for the nth neighbor probability distribution function, the radial distribution function, and the structure factor, a very good agreement being observed upon comparison with simulation data from the literature. Moreover, we have analyzed the scaling form for the disappearance of defects in the zigzag configuration for high pressure and have obtained the translational correlation length and the structural crossover in the oscillation frequency for asymptotically large distances.

5.
J Chem Phys ; 158(15)2023 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-37094005

RESUMO

The exact transfer-matrix solution for the longitudinal equilibrium properties of the single-file hard-disk fluid is used to study the limiting low- and high-pressure behaviors analytically as functions of the pore width. In the low-pressure regime, the exact third and fourth virial coefficients are obtained, which involve single and double integrals, respectively. Moreover, we show that the standard irreducible diagrams do not provide a complete account of the virial coefficients in confined geometries. The asymptotic equation of state in the high-pressure limit is seen to present a simple pole at the close-packing linear density, as in the hard-rod fluid, but, in contrast to the latter case, the residue is 2. Since, for an arbitrary pressure, the exact transfer-matrix treatment requires the numerical solution of an eigenvalue integral equation, we propose here two simple approximations to the equation of state, with different complexity levels, and carry out an extensive assessment of their validity and practical convenience vs the exact solution and available computer simulations.

6.
J Chem Phys ; 159(15)2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37861120

RESUMO

The phase behavior and structural properties of hard anisotropic particles (prisms and dumbbells) are examined in one-dimensional channels using the Parsons-Lee (PL) theory, and the transfer-matrix and neighbor-distribution methods. The particles are allowed to move freely along the channel, while their orientations are constrained such that one particle can occupy only two or three different lengths along the channel. In this confinement setting, hard prisms behave as an additive mixture, while hard dumbbells behave as a non-additive one. We prove that all methods provide exact results for the phase properties of hard prisms, while only the neighbor-distribution and transfer-matrix methods are exact for hard dumbbells. This shows that non-additive effects are incorrectly included into the PL theory, which is a successful theory of the isotropic-nematic phase transition of rod-like particles in higher dimensions. In the one-dimensional channel, the orientational ordering develops continuously with increasing density, i.e., the system is isotropic only at zero density, while it becomes perfectly ordered at the close-packing density. We show that there is no orientational correlation in the hard prism system, while the hard dumbbells are orientationally correlated with diverging correlation length at close packing. On the other hand, positional correlations are present for all the systems, the associated correlation length diverging at close packing.

7.
Mod Pathol ; 35(9): 1175-1180, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35361888

RESUMO

Current public health initiatives to contain the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) global pandemic focus on expanding vaccination efforts to include vulnerable populations such as pregnant people. Vaccines using messenger ribonucleic acid (mRNA) technology rely on translation by immune cells, primarily at the injection site. Hesitancy remains among the general population regarding the safety of mRNA vaccines during gestation, and it remains unknown whether the SARS-CoV-2 Spike protein (the product of mRNA vaccines available) accumulates in the placenta after vaccination. Objective: To determine whether Spike protein translation and accumulation occurs in placental tissue in the context of recent mRNA SARC-CoV-2 vaccination during pregnancy. We identified 48 patients receiving one or two doses of mRNA SARS-CoV-2 vaccine during gestation and used immunohistochemistry against SARS-CoV-2 Spike protein in formalin-fixed, paraffin-embedded placental tissue. One placenta, positive for SARS-CoV-2 RNA by in situ hybridization (ISH) was used as positive control. Seven term placentas collected prior to the emergence of SARS-CoV-2 served as negative controls. Eighty one percent of patients in the study group underwent third-trimester delivery; remaining had a first-trimester spontaneous abortion or elective second-trimester termination. Patients received two (52%) or one (48%) vaccine doses during pregnancy, with a median interval between latest dose and delivery of 13 days (range 2-79 days). Most (63%) cases had their latest dose within 15 days prior to delivery. All the placentas in the study and negative control groups were negative for SARS-CoV-2 immunohistochemistry. Six study cases with short vaccine-delivery intervals (2-7 days) were subjected to SARS-CoV-2 ISH and were negative. Our findings suggest that mRNA vaccines do not reach significant concentrations in the placenta given the absence of definitive SARS-CoV-2 Spike protein accumulation in placental tissue. This observation provides evidence supporting the safety of mRNA vaccines to the placental-fetal unit.


Assuntos
Vacinas contra COVID-19 , COVID-19 , Placenta , Complicações Infecciosas na Gravidez , Glicoproteína da Espícula de Coronavírus , COVID-19/prevenção & controle , Vacinas contra COVID-19/administração & dosagem , Feminino , Humanos , Placenta/virologia , Gravidez , Complicações Infecciosas na Gravidez/prevenção & controle , Complicações Infecciosas na Gravidez/virologia , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/análise , Vacinação
8.
Int J Mol Sci ; 23(22)2022 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-36430385

RESUMO

Extensive burns represent a significant challenge in biomedicine due to the multiple systemic and localized complications resulting from the major skin barrier loss. The functionalization of xenografts with nanostructured antibacterial agents proposes a fast and accessible application to restore barrier function and prevent localized bacterial contamination. Based on this, the objective of this work was to functionalize a xenograft by electrospray deposition with silver nanoparticles (AgNPs) and to evaluate its antibiofilm and cytotoxic effects on human fibroblasts. Initially, AgNPs were synthesized by a green microwave route with sizes of 2.1, 6.8, and 12.2 nm and concentrations of 0.055, 0.167, and 0.500 M, respectively. The AgNPs showed a size relationship directly proportional to the concentration of AgNO3, with a spherical and homogeneous distribution determined by high-resolution transmission electron microscopy. The surface functionalization of radiosterilized porcine skin (RPS) via electrospray deposition with the three AgNP concentrations (0.055, 0.167, and 0.500 M) in the epidermis and the dermis showed a uniform distribution on both surfaces by energy-dispersive X-ray spectroscopy. The antibiofilm assays of clinical multidrug-resistant Pseudomonas aeruginosa showed significant effects at the concentrations of 0.167 and 0.500 M, with a log reduction of 1.3 and 2.6, respectively. Additionally, viability experiments with human dermal fibroblasts (HDF) exposed to AgNPs released from functionalized porcine skin showed favorable tolerance, with retention of viability more significant than 90% for concentrations of 0.05 and 0.167 M after 24 h exposure. Antibacterial activity combined with excellent biocompatibility makes this biomaterial a candidate for antibacterial protection by inhibiting bacterial biofilms in deep burns during early stages of development.


Assuntos
Queimaduras , Nanopartículas Metálicas , Humanos , Suínos , Prata/química , Nanopartículas Metálicas/uso terapêutico , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Antibacterianos/química , Biofilmes , Bactérias , Queimaduras/tratamento farmacológico
9.
Entropy (Basel) ; 24(10)2022 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-37420455

RESUMO

We study a dilute granular gas immersed in a thermal bath made of smaller particles with masses not much smaller than the granular ones in this work. Granular particles are assumed to have inelastic and hard interactions, losing energy in collisions as accounted by a constant coefficient of normal restitution. The interaction with the thermal bath is modeled by a nonlinear drag force plus a white-noise stochastic force. The kinetic theory for this system is described by an Enskog-Fokker-Planck equation for the one-particle velocity distribution function. To get explicit results of the temperature aging and steady states, Maxwellian and first Sonine approximations are developed. The latter takes into account the coupling of the excess kurtosis with the temperature. Theoretical predictions are compared with direct simulation Monte Carlo and event-driven molecular dynamics simulations. While good results for the granular temperature are obtained from the Maxwellian approximation, a much better agreement, especially as inelasticity and drag nonlinearity increase, is found when using the first Sonine approximation. The latter approximation is, additionally, crucial to account for memory effects such as Mpemba and Kovacs-like ones.

10.
Int J Mol Sci ; 22(8)2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33923711

RESUMO

There has been a recent increase in the exploration of cold-active ß-galactosidases, as it offers new alternatives for the dairy industry, mainly in response to the current needs of lactose-intolerant consumers. Since extremophilic microbial compounds might have unique physical and chemical properties, this research aimed to study the capacity of Antarctic bacterial strains to produce cold-active ß-galactosidases. A screening revealed 81 out of 304 strains with ß-galactosidase activity. The strain Se8.10.12 showed the highest enzymatic activity. Morphological, biochemical, and molecular characterization based on whole-genome sequencing confirmed it as the first Rahnella inusitata isolate from the Antarctic, which retained 41-62% of its ß-galactosidase activity in the cold (4 °C-15 °C). Three ß-galactosidases genes were found in the R. inusitata genome, which belong to the glycoside hydrolase families GH2 (LacZ and EbgA) and GH42 (BglY). Based on molecular docking, some of these enzymes exhibited higher lactose predicted affinity than the commercial control enzyme from Aspergillus oryzae. Hence, this work reports a new Rahnella inusitata strain from the Antarctic continent as a prominent cold-active ß-galactosidase producer.


Assuntos
Temperatura Baixa , Rahnella/enzimologia , beta-Galactosidase/metabolismo , Aclimatação , Estabilidade Enzimática , Rahnella/genética , beta-Galactosidase/química , beta-Galactosidase/genética
11.
J Chem Phys ; 153(12): 120901, 2020 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-33003724

RESUMO

This Perspective article provides an overview of some of our analytical approaches to the computation of the structural and thermodynamic properties of single-component and multicomponent hard-sphere fluids. For the structural properties, they yield a thermodynamically consistent formulation, thus improving and extending the known analytical results of the Percus-Yevick theory. Approximate expressions linking the equation of state of the single-component fluid to the one of the multicomponent mixtures are also discussed.

12.
Entropy (Basel) ; 22(11)2020 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-33287073

RESUMO

Finding the proper entropy-like Lyapunov functional associated with the inelastic Boltzmann equation for an isolated freely cooling granular gas is a still unsolved challenge. The original H-theorem hypotheses do not fit here and the H-functional presents some additional measure problems that are solved by the Kullback-Leibler divergence (KLD) of a reference velocity distribution function from the actual distribution. The right choice of the reference distribution in the KLD is crucial for the latter to qualify or not as a Lyapunov functional, the asymptotic "homogeneous cooling state" (HCS) distribution being a potential candidate. Due to the lack of a formal proof far from the quasielastic limit, the aim of this work is to support this conjecture aided by molecular dynamics simulations of inelastic hard disks and spheres in a wide range of values for the coefficient of restitution (α) and for different initial conditions. Our results reject the Maxwellian distribution as a possible reference, whereas they reinforce the HCS one. Moreover, the KLD is used to measure the amount of information lost on using the former rather than the latter, revealing a non-monotonic dependence with α.

13.
Entropy (Basel) ; 22(4)2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-33286243

RESUMO

New proposals for the equation of state of four- and five-dimensional hard-hypersphere mixtures in terms of the equation of state of the corresponding monocomponent hard-hypersphere fluid are introduced. Such proposals (which are constructed in such a way so as to yield the exact third virial coefficient) extend, on the one hand, recent similar formulations for hard-disk and (three-dimensional) hard-sphere mixtures and, on the other hand, two of our previous proposals also linking the mixture equation of state and the one of the monocomponent fluid but unable to reproduce the exact third virial coefficient. The old and new proposals are tested by comparison with published molecular dynamics and Monte Carlo simulation results and their relative merit is evaluated.

14.
Malar J ; 18(1): 21, 2019 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-30678733

RESUMO

BACKGROUND: Current World Health Organization recommendations for the management of malaria include the need for a parasitological confirmation prior to triggering appropriate treatment. The use of rapid diagnostic tests (RDTs) for malaria has contributed to a better infection recognition and a more targeted treatment. Nevertheless, low-density infections and parasites that fail to produce HRP2 can cause false-negative RDT results. Microscopy has traditionally been the methodology most commonly used to quantify malaria and characterize the infecting species, but the wider use of this technique remains challenging, as it requires trained personnel and processing capacity. OBJECTIVE: In this study, the feasibility of an on-line system for remote malaria species identification and differentiation has been investigated by crowdsourcing the analysis of digitalized infected thin blood smears by non-expert observers using a mobile app. METHODS: An on-line videogame in which players learned how to differentiate the young trophozoite stage of the five Plasmodium species has been designed. Images were digitalized with a smartphone camera adapted to the ocular of a conventional light microscope. Images from infected red blood cells were cropped and puzzled into an on-line game. During the game, players had to decide the malaria species (Plasmodium falciparum, Plasmodium malariae, Plasmodium vivax, Plasmodium ovale, Plasmodium knowlesi) of the infected cells that were shown in the screen. After 2 months, each player's decisions were analysed individually and collectively. RESULTS: On-line volunteers playing the game made more than 500,000 assessments for species differentiation. Statistically, when the choice of several players was combined (n > 25), they were able to significantly discriminate Plasmodium species, reaching a level of accuracy of 99% for all species combinations, except for P. knowlesi (80%). Non-expert decisions on which Plasmodium species was shown in the screen were made in less than 3 s. CONCLUSION: These findings show that it is possible to train malaria-naïve non-experts to identify and differentiate malaria species in digitalized thin blood samples. Although the accuracy of a single player is not perfect, the combination of the responses of multiple casual gamers can achieve an accuracy that is within the range of the diagnostic accuracy made by a trained microscopist.


Assuntos
Crowdsourcing/estatística & dados numéricos , Malária/classificação , Sistemas On-Line/estatística & dados numéricos , Plasmodium/classificação , Jogos de Vídeo/estatística & dados numéricos , Especificidade da Espécie , Trofozoítos/classificação
15.
Lung ; 197(1): 89-94, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30474709

RESUMO

PURPOSE: Diabetes mellitus (DBM) reduces immunological activity and increases susceptibility to various infections, including tuberculosis (TB). Human alveolar macrophage (hAM) functions are altered in DBM. METHODS: To mimic hyperglycemic conditions in the lung alveolus, we co-cultured a hAM cell line (Daisy cell line) with human umbilical vein endothelial cells for 48 h in the presence of culture media alone, normal glucose (5 mM), and high glucose (22 mM). Using flow cytometry, immunophenotype characterization included cell surface markers CD 11c, CD14, CD16, CD86, CD163, CD169, CD206, CX3CR-1, CSF-1R, and matrix metalloproteinase-9 (MMP9). Phagocytic function was measured by immunofluorescence microscopy at 24 h after inoculation of cells with GFP-expressing Mycobacterium smegmatis. RESULTS: Direct exposure of AMs to high glucose and exposure in the co-culture system yield different results for the same phenotypic markers. MMP9 expression was increased under both conditions. CD169 and CX3CR1 expressions were decreased when AMs were exposed directly to high glucose but increased under co-culture. Immunofluorescence assay revealed that phagocytosis decreased in AMs when directly exposed to increased glucose levels from 2.5 mM to normal glucose (5 mM), yet AMs under co-culture did not show decreased phagocytosis until concentrations were raised to 25 mM. CONCLUSION: Alteration in the expression of certain receptors may contribute to defective sentinel function of AMs, promoting susceptibility to TB in a diabetic host. Variability in cell surface marker expression under direct glucose exposure compared to exposure via co-culture reveals that cell signaling between endothelial cells and AMs may play a crucial role in the phenotypic expression of AMs.


Assuntos
Glucose/farmacologia , Macrófagos Alveolares/efeitos dos fármacos , Mycobacterium smegmatis/fisiologia , Fagocitose/efeitos dos fármacos , Antígenos CD/metabolismo , Receptor 1 de Quimiocina CX3C/metabolismo , Comunicação Celular , Linhagem Celular , Técnicas de Cocultura , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/microbiologia , Metaloproteinase 9 da Matriz/metabolismo , Fenótipo , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo
16.
J Chem Phys ; 148(21): 214503, 2018 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-29884046

RESUMO

A detailed comparison between the Boublík-Mansoori-Carnahan-Starling-Leland (BMCSL) equation of state of hard-sphere mixtures is made with Molecular Dynamics (MD) simulations of the same compositions. The Labík and Smith simulation technique [S. Labík and W. R. Smith, Mol. Simul. 12, 23-31 (1994)] was used to implement the Widom particle insertion method to calculate the excess chemical potential, ßµ0ex, of a test particle of variable diameter, σ0, immersed in a hard-sphere fluid mixture with different compositions and values of the packing fraction, η. Use is made of the fact that the only polynomial representation of ßµ0ex which is consistent with the limits σ0 → 0 and σ0 → ∞ has to be of the cubic form, i.e., c0(η)+c¯1(η)σ0/M1+c¯2(η)(σ0/M1)2+c¯3(η)(σ0/M1)3, where M1 is the first moment of the distribution. The first two coefficients, c0(η) and c¯1(η), are known analytically, while c¯2(η) and c¯3(η) were obtained by fitting the MD data to this expression. This in turn provides a method to determine the excess free energy per particle, ßaex, in terms of c¯2, c¯3, and the compressibility factor, Z. Very good agreement between the BMCSL formulas and the MD data is found for ßµ0ex, Z, and ßaex for binary mixtures and continuous particle size distributions with the top-hat analytic form. However, the BMCSL theory typically slightly underestimates the simulation values, especially for Z, differences which the Boublík-Carnahan-Starling-Kolafa formulas and an interpolation between two Percus-Yevick routes capture well in different ranges of the system parameter space.

17.
J Chem Phys ; 148(19): 194505, 2018 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-30307191

RESUMO

The interest in the description of the properties of fluids of restricted dimensionality is growing for theoretical and practical reasons. In this work, we have firstly developed an analytical expression for the Helmholtz free energy of the two-dimensional square-well fluid in the Barker-Henderson framework. This equation of state is based on an approximate analytical radial distribution function for d-dimensional hard-sphere fluids (1 ≤ d ≤ 3) and is validated against existing and new simulation results. The so-obtained equation of state is implemented in a discrete perturbation theory able to account for general potential shapes. The prototypical Lennard-Jones and Yukawa fluids are tested in its two-dimensional version against available and new simulation data with semiquantitative agreement.

18.
Mar Drugs ; 16(11)2018 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-30453540

RESUMO

The marine nemertean Cephalothrix simula originates from the Pacific Ocean but in recent years has been discovered in northern Europe. The species has been associated with high levels of the marine neurotoxin Tetrodotoxin, traditionally associated with Pufferfish Poisoning. This study reports the first discovery of two organisms of C. simula in the UK, showing the geographical extent of this species is wider than originally described. Species identification was initially conducted morphologically, with confirmation by Cox 1 DNA sequencing. 16S gene sequencing enabled the taxonomic assignment of the microbiome, showing the prevalence of a large number of bacterial genera previously associated with TTX production including Alteromonas, Vibrio and Pseudomonas. LC-MS/MS analysis of the nemertean tissue revealed the presence of multiple analogues of TTX, dominated by the parent TTX, with a total toxin concentration quantified at 54 µg TTX per g of tissue. Pseudomonas luteola isolated from C. simula, together with Vibrio alginolyticus from the native nemertean Tubulanus annulatus, were cultured at low temperature and both found to contain TTX. Overall, this paper confirms the high toxicity of a newly discovered invasive nemertean species with links to toxin-producing marine bacteria and the potential risk to human safety. Further work is required to assess the geographical extent and toxicity range of C. simula along the UK coast in order to properly gauge the potential impacts on the environment and human safety.


Assuntos
Organismos Aquáticos/microbiologia , Espécies Introduzidas , Invertebrados/microbiologia , Pseudomonas/metabolismo , Tetrodotoxina/metabolismo , Vibrio alginolyticus/metabolismo , Animais , Organismos Aquáticos/metabolismo , Cromatografia Líquida de Alta Pressão , DNA Bacteriano/isolamento & purificação , Inglaterra , Invertebrados/metabolismo , Microbiota , Pseudomonas/genética , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Espectrometria de Massas em Tandem , Tetrodotoxina/isolamento & purificação , Vibrio alginolyticus/genética , Vibrio alginolyticus/isolamento & purificação
19.
Entropy (Basel) ; 20(7)2018 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-33265633

RESUMO

The residual multiparticle entropy (RMPE) of a fluid is defined as the difference, Δs, between the excess entropy per particle (relative to an ideal gas with the same temperature and density), sex, and the pair-correlation contribution, s2. Thus, the RMPE represents the net contribution to sex due to spatial correlations involving three, four, or more particles. A heuristic "ordering" criterion identifies the vanishing of the RMPE as an underlying signature of an impending structural or thermodynamic transition of the system from a less ordered to a more spatially organized condition (freezing is a typical example). Regardless of this, the knowledge of the RMPE is important to assess the impact of non-pair multiparticle correlations on the entropy of the fluid. Recently, an accurate and simple proposal for the thermodynamic and structural properties of a hard-sphere fluid in fractional dimension 1

20.
Phys Rev Lett ; 119(14): 148001, 2017 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-29053323

RESUMO

Under certain conditions, two samples of fluid at different initial temperatures present a counterintuitive behavior known as the Mpemba effect: it is the hotter system that cools sooner. Here, we show that the Mpemba effect is present in granular fluids, both in uniformly heated and in freely cooling systems. In both cases, the system remains homogeneous, and no phase transition is present. Analytical quantitative predictions are given for how differently the system must be initially prepared to observe the Mpemba effect, the theoretical predictions being confirmed by both molecular dynamics and Monte Carlo simulations. Possible implications of our analysis for other systems are also discussed.

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