470 research outputs found
Equation of State of Wet Granular Matter
A theory is derived for the nonequilibrium probability currents of the
capillary interaction which determines the pair correlation function near
contact. This yields an analytic expression for the equation of state, P =
P(N/V,T), of wet granular matter for D=2 dimensions, valid in the complete
density range from gas to jamming. Driven wet granular matter exhibits a
van-der-Waals-like unstable branch at granular temperatures T<T_c corresponding
to a first order segregation transition of clusters. For the realistic rupture
length of the liquid bridge, s_crit=0.07 d, the critical point is located at
T_c = 0.274 E_cb. While the critical temperature weakly depends on the rupture
length, the critical density phi_c is shown to scale with s_crit according to
s_crit = 4d (sqrt(phi_J / phi_c) -1). The segregation transition is closely
related to the precipitation of granular droplets reported for the free cooling
of one-dimensional wet granular matter [Phys. Rev. Lett. 97, 078001 (2006)],
and extends the effect to higher dimensional systems. Since the limiting case
of sticky bonds, E_cb >> T, is of relevance for aggregation in general,
simulations have been performed which show very good agreement with the
theoretically predicted coordination K of capillary bonds as a function of the
bond length s_crit. This result implies that particles that stick at the
surface, s_crit=0, form isostatic clusters.Comment: 29 pages, 20 figure
Chaoticity of the Wet Granular Gas
In this work we derive an analytic expression for the Kolmogorov-Sinai
entropy of dilute wet granular matter, valid for any spatial dimension. The
grains are modelled as hard spheres and the influence of the wetting liquid is
described according to the Capillary Model, in which dissipation is due to the
hysteretic cohesion force of capillary bridges. The Kolmogorov-Sinai entropy is
expanded in a series with respect to density. We find a rapid increase of the
leading term when liquid is added. This demonstrates the sensitivity of the
granular dynamics to humidity, and shows that the liquid significantly
increases the chaoticity of the granular gas.Comment: 13 pages, 10 figures, Physical Review
Rejection of the name Borreliella gen. nov. and all proposed species comb. nov. placed therein. Request for an opinion
Rejection (nomen rejiciendum) of the name Borreliella gen. nov. and all new combinations therein is being requested on grounds of risk to human health and patient safety (Principle 1, subprinciple 2 and Rule 56a) and violation to aim for stability of names, avoid useless creation of names (Principle 1, subprinciple 1 and 3) and that names should not be changed without sufficient reason (Principle 9 of the Code)
The genus Borrelia reloaded
The genus Borrelia, originally described by Swellengrebel in 1907, contains tick- or louse-transmitted spirochetes belonging to the relapsing fever (RF) group of spirochetes, the Lyme borreliosis (LB) group of spirochetes and spirochetes that form intermittent clades. In 2014 it was proposed that the genus Borrelia should be separated into two genera; Borrelia Swellengrebel 1907 emend. Adeolu and Gupta 2014 containing RF spirochetes and Borreliella Adeolu and Gupta 2014 containing LB group of spirochetes. In this study we conducted an analysis based on a method that is suitable for bacterial genus demarcation, the percentage of conserved proteins (POCP). We included RF group species, LB group species and two species belonging to intermittent clades, Borrelia turcica GĂĽner et al. 2004 and Candidatus Borrelia tachyglossi Loh et al. 2017. These analyses convincingly showed that all groups of spirochetes belong into one genus and we propose to emend, and re-unite all groups in, the genus Borrelia
Novel approaches for the serodiagnosis of louse-borne relapsing fever
Louse-borne relapsing fever (LBRF) caused by B. recurrentis is a poverty-related and neglected infectious disease with an endemic focus in the Horn of Africa. Re-emergence of the disease occurred in Europe during the refugee crisis in 2015 and sporadic outbreaks were frequently reported in Eastern Africa where poor settings lack affordable diagnostics. Currently, there are no validated in vitro assays available for the serodiagnosis of LBRF. The aim of this study was to develop novel and reliable immunoassays by investigating clinically suspected and culture-confirmed serum samples from LBRF patients and a broad panel of serum samples from patients with other spirochetal, bacterial, and parasitic diseases. We identified two immunoreactive antigens (complement-inhibiting protein CihC and the glycerophosphodiester phosphodiesterase GlpQ of B. recurrentis) as the most promising target candidates leading to the evaluation of two immunoassays (line immunoblot and ELISA) for IgM and IgG. To optimize the IgM immunoassay, we conducted a bioinformatic approach to localize the relevant immunogenic regions within CihC. By utilizing a N-terminal CihC fragment, the sensitivity and specificity of both immunoassays (CihC and GlpQ) were high (IgM: sensitivity 100%, specificity of 89.9%, IgG: sensitivity 100%, specificity 99.2%). In conclusion, our findings indicate the diagnostic potential of CihC and GlpQ as valuable markers for the serodiagnosis of LBRF even at early time points of infection. Here, we provide strong evidence for the utilization of these immunoassays as reliable tools in clinical practice
Path-integral analysis of fluctuation theorems for general Langevin processes
We examine classical, transient fluctuation theorems within the unifying
framework of Langevin dynamics. We explicitly distinguish between the effects
of non-conservative forces that violate detailed balance, and non-autonomous
dynamics arising from the variation of an external parameter. When both these
sources of nonequilibrium behavior are present, there naturally arise two
distinct fluctuation theorems.Comment: 24 pages, one figur
A Case of Relapsing-Remitting Neuroborreliosis? Challenges in the Differential Diagnosis of Recurrent Myelitis
We report the case of a 31-year-old woman with 4 episodes of myelitis with pleocytosis, a positive Borrelia burgdorferi serology with positive antibody indices, and full recovery each time after antibiotic and steroid treatment, suggesting neuroborreliosis. We nevertheless believe that recurrent neuroborreliosis is improbable based on the levels of the chemokine CXCL13 in cerebrospinal fluid and favor the diagnosis of post-infectious autoimmune-mediated transverse myelitis possibly triggered by an initial neuroborreliosis as the cause of the relapses observed in our patient. We demonstrate the diagnostic steps and procedures which were important in the differential diagnosis of this unusual and challenging case
Trans-Atlantic exchanges have shaped the population structure of the Lyme disease agent Borrelia burgdorferi sensu stricto
The origin and population structure of Borrelia burgdorferi sensu stricto (s.s.), the agent of Lyme disease, remain obscure. This tick-transmitted bacterial species occurs in both North America and Europe. We sequenced 17 European isolates (representing the most frequently found sequence types in Europe) and compared these with 17 North American strains. We show that trans-Atlantic exchanges have occurred in the evolutionary history of this species and that a European origin of B. burgdorferi s. s. is marginally more likely than a USA origin. The data further suggest that some European human patients may have acquired their infection in North America. We found three distinct genetically differentiated groups: i) the outgroup species Borrelia bissettii, ii) two divergent strains from Europe, and iii) a group composed of strains from both the USA and Europe. Phylogenetic analysis indicated that different genotypes were likely to have been introduced several times into the same area. Our results demonstrate that irrespective of whether B. burgdorferi s. s. originated in Europe or the USA, later trans-Atlantic exchange(s) have occurred and have shaped the population structure of this genospecies. This study clearly shows the utility of next generation sequencing to obtain a better understanding of the phylogeography of this bacterial species
Louse-borne relapsing fever (Borrelia recurrentis) diagnosed in 15 refugees from northeast Africa: epidemiology and preventive control measures, Bavaria, Germany, July to October 2015
We report 15 imported louse-borne relapsing fever (LBRF) cases in refugees in Bavaria, Germany. One patient died. Epidemiological findings confirmed that all were young males from the Horn of Africa (12 from Somalia), who had similar migration routes converging in Sudan continuing through Libya and Italy. The majority likely acquired their infection during migration. Healthcare workers should be aware of LBRF in refugees passing through north Africa to ensure correct treatment and preventive measures.</jats:p
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