Thawed matrix method for computing local mechanical properties of amorphous solids.

We present a method for computing locally varying nonlinear mechanical properties in particle simulations of amorphous solids. Plastic rearrangements outside a probed region are suppressed by introducing an external field that directly penalizes large nonaffine displacements. With increasing strength of the field, plastic deformation can be localized.

Ecological and clinical evidence of the establishment of West Nile virus in a large urban area in Europe, Berlin, Germany, 2021 to 2022.

BackgroundWest Nile virus (WNV), found in Berlin in birds since 2018 and humans since 2019, is a mosquito-borne virus that can manifest in humans as West Nile fever (WNF) or neuroinvasive disease (WNND). However, human WNV infections and associated disease are likely underdiagnosed.AimWe aimed to identify and genetically characterise WNV infections in humans and mosquitoes in Berlin.

Efficient sequestration of malachite green in aqueous solution by laterite-rice husk ash-based alkali-activated materials: parameters and mechanism.

In this work, laterite (LA) and rice husk ash (RHA)-based alkali-activated materials (AAMs) with varying %RHA contents (0, 5, 10, 15, and 20%) were prepared for the removal of malachite green (MG) dye from water. The precursors and AAMs were characterized by standard methods (XRF, XRD, TG/DTA SEM, and FTIR). The SEM micrographs and iodine index values showed that the incorporation of RHA improves the microporosity of laterite-based geopolymers.

Analysis of two choir outbreaks acting in concert to characterize long- range transmission risks through SARS-CoV-2, Berlin, Germany, 2020.

Background: Superspreading events are important drivers of the SARS-CoV-2 pandemic and long-range (LR) transmission is believed to play a major role. We investigated two choir outbreaks with different attack rates (AR) to analyze the contribution of LR transmission and highlight important measures for prevention.

Methods: We conducted two retrospective cohort studies and obtained demographic, clinical, laboratory and contact data, performed SARS-CoV-2 serology, whole genome sequencing (WGS), calculated LR transmission probabilities, measured particle emissions of selected choir members, and calculated particle air concentrations and inhalation doses.

Stress overshoot, hysteresis, and the Bauschinger effect in sheared dense colloidal suspensions.

The mechanical nonlinear response of dense Brownian suspensions of polymer gel particles is studied experimentally and by means of numerical simulations. It is shown that the response to the application of a constant shear rate depends on the previous history of the suspension. When the flow starts from a suspension at rest, it exhibits an elastic response followed by a stress overshoot and then a plastic flow regime.

Effects of Iron Minerals on the Compressive Strengths and Microstructural Properties of Metakaolin-Based Geopolymer Materials.

The current study aims to investigate the influence of iron minerals on the amorphous phase content, compressive strengths and the microstructural properties of the geopolymer materials. Geopolymer materials were prepared by the substitution of metakaolin by 10 and 20 wt.% of each iron mineral sample.

Computational indentation in highly cross-linked polymer networks.

Indentation is a common experimental technique to study the mechanics of polymeric materials. The main advantage of using indentation is this provides a direct correlation between the microstructure and the small-scale mechanical response, which is otherwise difficult within the standard tensile testing. The majority of studies have investigated hydrogels, microgels, elastomers, and even soft biomaterials.

[Healthcare-associated infections and antimicrobial use in long-term care facilities. German results of the third European point prevalence survey HALT-3].

Background And Objective: The essential role of infection prevention in long-term care facilities has become evident during the current SARS-CoV‑2 pandemic. In order to obtain a reliable database on nosocomial infections and antibiotic use, the European Centre for Disease Prevention and Control (ECDC) initiated the third point prevalence survey in European long-term care facilities from 2016 to 2017 (HALT-3).

Material And Methods: In Germany, 131 facilities with 10,565 residents participated voluntarily.

A shift from travel-associated cases to autochthonous transmission with Berlin as epicentre of the monkeypox outbreak in Germany, May to June 2022.

By 22 June 2022, 521 cases of monkeypox were notified in Germany. The median age was 38 years (IQR: 32-44); all cases were men. In Berlin, where 69% of all cases occurred, almost all were men who have sex with men.

The Effect of Gel-Type Contributions in Lime-Sand Bricks, Alkali-Activated Slags and CEMI/CEMIII Pastes: Implications for Next Generation Concretes.

Lime-sand bricks of different ages were investigated using IR-spectroscopy, thermogravimetry, and X-ray diffraction/scattering. After subtraction of the dominant quartz contribution (80%), the IR spectra show the absorption peaks of the hydrothermally formed binder phases. The spectra also show the alteration of the binder during ageing under atmospheric conditions by the influence of CO forming carbonate and a condensed SiO-gel (secondary gel).

Signatures of the spatial extent of plastic events in the yielding transition in amorphous solids.

Amorphous solids are yield stress materials that flow when a sufficient load is applied. Their flow consists of periods of elastic loading interrupted by rapid stress drops, or avalanches, coming from microscopic rearrangements known as shear transformations (STs). Here we show that the spatial extent of avalanches in a steadily sheared amorphous solid has a profound effect on the distribution of local residual stresses that in turn determines the stress drop statistics.

Ripple-like instability in the simulated gel phase of finite size phosphocholine bilayers.

Atomistic molecular dynamics simulations have reached a degree of maturity that makes it possible to investigate the lipid polymorphism of model bilayers over a wide range of temperatures. However if both the fluid L and tilted gel [Formula: see text] states are routinely obtained, the [Formula: see text] ripple phase of phosphatidylcholine lipid bilayers is still unsatifactorily described. Performing simulations of lipid bilayers made of different numbers of DPPC (1,2-dipalmitoylphosphatidylcholine) molecules ranging from 32 to 512, we demonstrate that the tilted gel phase [Formula: see text] expected below the pretransition cannot be obtained for large systems (equal or larger than 94 DPPC molecules) through common simulations settings or temperature treatments.

MLLPA: A Machine Learning-assisted Python module to study phase-specific events in lipid membranes.

Machine Learning-assisted Lipid Phase Analysis (MLLPA) is a new Python 3 module developed to analyze phase domains in a lipid membrane based on lipid molecular states. Reading standard simulation coordinate and trajectory files, the software first analyze the phase composition of the lipid membrane by using machine learning tools to label each individual molecules with respect to their state, and then decompose the simulation box using Voronoi tessellations to analyze the local environment of all the molecules of interest. MLLPA is versatile as it can read from multiple format (e.

Composition fluctuations in polydisperse liquids: Glasslike effects well above the glass transition.

We study a two-dimensional glass-forming system of slightly polydisperse (LJ) particles using molecular dynamics simulations and demonstrate that in the liquid regime (well above the vitrification temperature) this model shows a number of features typical of the glass transition: (i) the relation between compressibility and structure factor S(q) is strongly violated; (ii) the dynamical structure factor S(q,t) at low q shows a two-step relaxation; (iii) the time-dependent heat capacity c_{v}(t) shows a long-time power-law tail. We show that these phenomena can be rationalized with the idea of composition fluctuations and provide a quantitative theory for the effects (i) and (ii). It implies that such effects must be inherent in all polydisperse colloidal models, including binary LJ mixtures.

Hepatitis A outbreak among MSM in Berlin due to low vaccination coverage: Epidemiology, management, and successful interventions.

Objectives: To describe the characteristics of a large hepatitis A virus (HAV) outbreak among men who have sex with men (MSM) in Berlin and to assess the impact of measures implemented.

Methods: Cases of laboratory-confirmed, symptomatic HAV infection notified in Berlin, Germany between August 2016 and February 2018 were analysed using routine and enhanced surveillance data including genotyping results. Several studies involving different groups of participants were conducted to further investigate the outbreak, including surveys on knowledge and practices of HAV vaccination among physicians and vaccination coverage and determinants of vaccination status among MSM.

Glassy dynamics of a binary Voronoi fluid: a mode-coupling analysis.

The binary Voronoi mixture is a fluid model whose interactions are derived from the Voronoi-Laguerre tessellation of the configurations of the system. The resulting interactions are local and many-body. Here we perform molecular-dynamics (MD) simulations of an equimolar mixture that is weakly polydisperse and additive.

Resurgence of an international hepatitis A outbreak linked to imported frozen strawberries, Germany, 2018 to 2020.

Following outbreaks linked to frozen strawberries in Sweden and Austria in 2018, 65 cases linked to the same hepatitis A virus strain were detected in Germany between October 2018 and January 2020, presenting in two waves. Two case-control studies and a comparison of cases' consumption frequencies with purchase data from a large consumer panel provided strong evidence for frozen strawberry cake as the main vehicle of transmission. Of 46 cases interviewed, 27 reported consuming frozen strawberry cake and 25 of these identified cake(s) from brand A spontaneously or in product picture-assisted recall.

Residual stress distributions in amorphous solids from atomistic simulations.

The distribution of local residual stresses (threshold to instability) that controls the statistical properties of plastic flow in athermal amorphous solids is examined with an atomistic simulation technique. For quiescent configurations, the distribution has a pseudogap (power-law) form with an exponent that agrees well with global yielding statistics. As soon as deformation sets in, the pseudogap region gives way to a system size dependent plateau at small residual stresses that can be understood from the statistics of local residual stress differences between plastic events.

A machine learning study of the two states model for lipid bilayer phase transitions.

We have adapted a set of classification algorithms, also known as machine learning, to the identification of fluid and gel domains close to the main transition of dipalmitoyl-phosphatidylcholine (DPPC) bilayers. Using atomistic molecular dynamics conformations in the low and high temperature phases as learning sets, the algorithm was trained to categorise individual lipid configurations as fluid or gel, in relation with the usual two-states phenomenological description of the lipid melting transition. We demonstrate that our machine can learn and sort lipids according to their most likely state without prior assumption regarding the nature of the order parameter of the transition.

Dating apps and websites as tools to reach anonymous sexual contacts during an outbreak of hepatitis A among men who have sex with men, Berlin, 2017.

BackgroundIn an outbreak of hepatitis A among men who have sex with men (MSM) in Berlin (2016 and 2017), patients frequently reported anonymous sex and use of dating applications to meet sexual contacts, hampering tracing and vaccination of contacts.AimOur objective was to evaluate dating apps and websites as a means of spreading prevention messages among MSM during the ongoing outbreak.MethodsAdvertisements in different formats were placed on three MSM dating apps and eight websites for anonymous dating during three weeks in March and April 2017.

Voronoi glass-forming liquids: A structural study.

We introduce a theoretical model of simple fluid, whose interactions, defined in terms of the Voronoi cells of the configurations, are local and many-body. The resulting system is studied both theoretically and numerically. We show that the fluid, though sharing the global features of other models of fluids with soft interactions, has several unusual characteristics, which are investigated and discussed.

Identification of Intermediates during the Hydration of Na[AlSiO](BH): A Combined Theoretical and Experimental Approach.

Tetrahydroborate sodalites have been discussed as possible materials for reversible hydrogen storage. In order to access the suitability of Na[AlSiO](BH), its reaction with water was investigated theoretically and experimentally. Density functional theory (DFT) calculations at the generalized gradient approximation (GGA) level were performed to identify the reaction intermediates.

Prevalence and risk factors for colonization by Clostridium difficile and extended-spectrum β-lactamase-producing Enterobacteriaceae in rehabilitation clinics in Germany.

Background: Rehabilitation clinics may vary widely in terms of type of care provided, duration of hospital stay, and case severity. Few data are available on prevalence of Clostridium difficile or extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) colonization in rehabilitation clinics in Germany.

Aim: This study investigated the frequency of intestinal colonization by these pathogens among patients in rehabilitation clinics of different specialization.