The transpeptidase sortase A of Staphylococcus aureus (Sa-SrtA) is a valuable tool in protein chemistry. The native enzyme anchors surface proteins containing a highly conserved LPxTG sorting motif to a terminal glycine residue of the peptidoglycan layer in Gram-positive bacteria. This reaction is exploited for sortase-mediated ligation (SML), allowing the site-specific linkage of synthetic peptides and recombinant proteins by a native peptide bond. However, the moderate catalytic efficiency and specificity of Sa-SrtA fueled the development of new biocatalysts for SML, including the screening of sortase A variants form microorganisms other than S. aureus and the directed protein evolution of the Sa-SrtA enzyme itself. Novel display platforms and screening formats were developed to isolate sortases with altered properties from mutant libraries. This yielded sortases with strongly enhanced catalytic activity and enzymes recognizing new sorting motifs as substrates. This minireview focuses on recent advances in the field of directed sortase evolution and applications of these tailor-made enzymes in biochemistry.Weniger anzeigen
The lower nocturnal boundary layer is governed by intermittent turbulence which is thought to be triggered by sporadic activity of so-called sub-mesoscale motions in a complex way. We analyze intermittent turbulence based on an assumed relation between the vertical gradients of the sub-mean scales and turbulence kinetic energy. We analyze high-resolution nocturnal eddy-correlation data from 30-m tower collected during the Fluxes over Snow Surfaces II field program. The non-turbulent velocity signal is decomposed using a discrete wavelet transform into three ranges of scales interpreted as the mean, jet and sub-mesoscales. The vertical gradients of the sub-mean scales are estimated using finite differences. The turbulence kinetic energy is modelled as a discrete-time autoregressive process with exogenous variables, where the latter ones are the vertical gradients of the sub-mean scales. The parameters of the discrete model evolve in time depending on the locally-dominant turbulence-production scales. The three regimes with averaged model parameters are estimated using a subspace-clustering algorithm which illustrates a weak bimodal distribution in the energy phase space of turbulence and sub-mesoscale motions for the very stable boundary layer. One mode indicates turbulence modulated by sub-mesoscale motions. Furthermore, intermittent turbulence appears if the sub-mesoscale intensity exceeds 10% of the mean kinetic energy in strong stratification.Weniger anzeigen
Systematic comparison of analysis methods of clinical microdialysis data for impact on target-site drug exposure and response. Methods
39 individuals received a 500 mg levofloxacin short-term infusion followed by 24-h dense sampling in plasma and microdialysate collection in interstitial space fluid (ISF). ISF concentrations were leveraged using non-compartmental (NCA) and compartmental analysis (CA) via (ii) relative recovery correction at midpoint of the collection interval (midpoint-NCA, midpoint-CA) and (ii) dialysate-based integrals of time (integral-CA). Exposure and adequacy of community-acquired pneumonia (CAP) therapy via pharmacokinetic/pharmacodynamic target-attainment (PTA) analysis were compared between approaches. Results
Individual AUCISF estimates strongly varied for midpoint-NCA and midpoint-CA (≥52.3%CV) versus integral-CA (≤32.9%CV) owing to separation of variability in PK parameters (midpoint-CA = 46.5%–143%CVPK, integral-CA = 26.4%–72.6%CVPK) from recovery-related variability only in integral-CA (41.0%–50.3%CVrecovery). This also led to increased variability of AUCplasma for midpoint-CA (56.0%CV) versus midpoint-NCA and integral-CA (≤33.0%CV), and inaccuracy of predictive model performance of midpoint-CA in plasma (visual predictive check). PTA analysis translated into 33% of evaluated patient cases being at risk of incorrectly rejecting recommended dosing regimens at CAP-related epidemiological cut-off values. Conclusions
Integral-CA proved most appropriate to characterise clinical pharmacokinetics- and microdialysis-related variability. Employing this knowledge will improve the understanding of drug target-site PK for therapeutic decision-making.Weniger anzeigen
Rapid urbanization has exerted considerable pressure on groundwater resources in Jaipur, India. Peri-urban areas are particularly affected as the public supply infrastructure often does not reach this fast-growing fringe, which often lacks a planning strategy, leading to an informal water supply based on groundwater. At the same time, the hills and historic reservoirs located in these areas are important for groundwater recharge and, therefore, critical for sustainable groundwater-resource management. To understand the local hydrogeology and the role of anthropogenic influences, a 2-year field study was carried out in northeastern Jaipur. The aim was to develop a conceptual model on which a management concept can be built. The study comprised hydrochemical and stable isotope analyses of water samples, depth-to-water measurements, a leveling survey and geophysical investigations. The study revealed that the groundwater from both the Proterozoic hard rock and the overlying Quaternary alluvial aquifer generally does not meet the Indian drinking water thresholds for nitrate concentration and/or total dissolved solids (TDS). While anthropogenic activities are the main source of quantity problems (declining groundwater levels through overabstraction), the biggest quality problems (nitrate up to 550 mg/L and TDS >500 mg/L) are most likely of geogenic origin and only enhanced by anthropogenic impacts. Quantity and quality aspects improve significantly in areas influenced by recharge from the historic reservoirs, leading to the conclusion that artificial recharge structures may be the way forward to improving community water supply and that groundwater protection should be given priority in these areas.Weniger anzeigen
This work concerns the zero Mach number limit of the compressible primitive equations. The primitive equations with the incompressibility condition are identified as the limiting equations. The convergence with well-prepared initial data (i.e., initial data without acoustic oscillations) is rigorously justified, and the convergence rate is shown to be of order O(ε), as ε→0+, where ε represents the Mach number. As a byproduct, we construct a class of global solutions to the compressible primitive equations, which are close to the incompressible flows.Weniger anzeigen
Since the run-up to the great recession, there has been a significant degree of heterogeneity across euro area countries both in terms of interest rates and in the composition of monetary assets. In order to account for the heterogeneity of monetary assets within and across member countries, we propose a Divisia monetary aggregate for the euro area. In line with earlier evidence obtained for the United States, our results from a panel probit analysis show that the divergence between the Divisia and the simple sum aggregate has a significant predictive content for recessions in euro area countries.Weniger anzeigen
The development of new drugs for diseases is a time-consuming, costly and risky process. In recent years, many drugs could be approved for other indications. This repurposing process allows to effectively reduce development costs, time and, ultimately, save patients' lives. During the ongoing COVID-19 pandemic, drug repositioning has gained widespread attention as a fast opportunity to find potential treatments against the newly emerging disease. In order to expand this field to researchers with varying levels of experience, we made an effort to open it to all users (meaning novices as well as experts in cheminformatics) by significantly improving the entry-level user experience. The browsing functionality can be used as a global entry point to collect further information with regards to small molecules (∼1 million), side-effects ∼110 000) or drug-target interactions (∼3 million). The drug-repositioning tab for small molecules will also suggest possible drug-repositioning opportunities to the user by using structural similarity measurements for small molecules using two different approaches. Additionally, using information from the Promiscuous 2.0 Database, lists of candidate drugs for given indications were precomputed, including a section dedicated to potential treatments for COVID-19. All the information is interconnected by a dynamic network-based visualization to identify new indications for available compounds. Promiscuous 2.0 is unique in its functionality and is publicly available at http://bioinformatics.charite.de/promiscuous2.Weniger anzeigen
Die vorliegende Studie untersucht die Überzeugungen und die Selbstwirksamkeitserwartungen in Bezug auf kulturelle Diversität von frühpädagogischen Fachkräften. Es wurde (1) untersucht, inwieweit multikulturelle Überzeugungen und diversitätsspezifische Selbstwirksamkeitserwartungen miteinander in Beziehung stehen und sich im zeitlichen Verlauf verändern, und (2) in welchem Zusammenhang die beiden Konstrukte mit der wahrgenommenen Wichtigkeit verschiedener sprachpädagogischer Förderstrategien in Kindertageseinrichtungen stehen. Dazu wurden in einer Längsschnittstudie 251 frühpädagogische Fachkräfte mit spezieller sprachpädagogischer Qualifikation zu zwei Messzeitpunkten befragt. Die Ergebnisse des Strukturgleichungsmodells zeigten, dass multikulturelle Überzeugungen und diversitätsspezifische Selbstwirksamkeitserwartungen in Zusammenhang stehende, aber eigenständige Konstrukte sind, die auf unterschiedliche Weise mit der eingeschätzten Wichtigkeit alltagsintegrierter und additiver Sprachförderansätze in kulturell diversen Gruppen assoziiert sind. So konnte für die multikulturellen Überzeugungen – im Vergleich zu den diversitätsspezifischen Selbstwirksamkeitserwartungen – ein signifikanter Zusammenhang zu der intendierten alltagsintegrierten sprachlichen Förderung festgestellt werden. Die Ergebnisse werden abschließend vor dem Hintergrund ihrer Relevanz für zukünftige Forschung und die Ausbildung frühpädagogischer Fachkräfte diskutiert.Weniger anzeigen
We analyze gender differences in immigrants’ ethnic boundary making using the example of name giving. We draw on the well-established finding that immigrants are more likely to choose a name that is common in the host country (strategy of boundary crossing) for female than for male descendants. We distinguish between two dimensions that help us to understand the gender gap in naming: the impact of origin-specific factors (institutionalization of gender equality in the country of origin and religious affiliation) and immigrants’ level of integration into the host country. Using data from the German Socio-Economic Panel Study on immigrants from 49 countries, we show that both sets of factors have a strong impact on immigrants’ boundary making in naming, as well as on the extent of the difference between daughters and sons: traditional gender role attitudes foster the gender gap in naming, whereas integration into the host country reduces it.Weniger anzeigen
The following article is based on the observation that digitalisation in the world of work does on the one hand trigger processes of change, leading to shifts and new constellations in the required qualifications. On the other hand, the effects of digitalisation on qualification requirements are moderated by work organisation. Against the background of a generalist understanding of academic and vocational qualifications, the article deals with the question what curricula correspond to the changing requirements of digitalisation under the new organizational circumstances of Industry 4.0. Turning to the discussion of preparatory qualifications for occupations in Industry 4.0, it follows the hypothesis that the technological developments that lead to a change in qualification needs also increase the potential to meet those needs. This leads to the idea of a digital signature pedagogy.Weniger anzeigen
We study Boolean networks which are simple spatial models of the highly conserved Delta–Notch system. The models assume the inhibition of Delta in each cell by Notch in the same cell, and the activation of Notch in presence of Delta in surrounding cells. We consider fully asynchronous dynamics over undirected graphs representing the neighbour relation between cells. In this framework, one can show that all attractors are fixed points for the system, independently of the neighbour relation, for instance by using known properties of simplified versions of the models, where only one species per cell is defined. The fixed points correspond to the so-called fine-grained “patterns” that emerge in discrete and continuous modelling of lateral inhibition. We study the reachability of fixed points, giving a characterisation of the trap spaces and the basins of attraction for both the full and the simplified models. In addition, we use a characterisation of the trap spaces to investigate the robustness of patterns to perturbations. The results of this qualitative analysis can complement and guide simulation-based approaches, and serve as a basis for the investigation of more complex mechanisms.Weniger anzeigen
Die Relevanz von Begegnungen in öffentlichen Räumen für das gesellschaftliche Zusammenleben in urbanen Quartieren und die Bedeutung der Gestaltung des Stadtraums sind viel diskutierte Themen in Stadtforschung und -planung. Meist werden die damit verbundenen Chancen, über solche Begegnungen die Akzeptanz gesellschaftlicher Vielfalt zu steigern, und die damit verbundenen Herausforderungen, die öffentliche Räume als Orte gesellschaftlicher Konflikte mit sich bringen können, kritisch gegenübergestellt und gegeneinander abgewogen. Obwohl also ein breites Wissen über öffentliche Räume als Orte der Begegnung besteht, ist es dennoch notwendig, seine Gültigkeit immer wieder in Bezug auf bestimmte lokale Kontexte zu überprüfen. Am Beispiel des superdiversen hannoverschen Quartiers Sahlkamp-Mitte kontrastiert der Artikel die der Freiraumgestaltung zugrunde liegenden planerischen Ideen mit alltäglichen Erfahrungen vom Zusammenleben der Bewohnerinnen und Bewohner. Es zeigt sich, dass hier Diskrepanzen bestehen und auch „organisierte Begegnungen“ im Freiraum einen produktiven Beitrag zum „guten Zusammenleben“ im Quartier leisten können.Weniger anzeigen
Where classical epidemiology has proven to be inadequate for surveillance and control of foodborne pathogens, molecular epidemiology, using genomic typing methods, can add value. However, the analysis of whole genome sequencing (WGS) data varies widely and is not yet fully harmonised. We used genomic data on 494 Listeria monocytogenes isolates from readyto- eat food products and food processing environments deposited in the strain collection of the German National Reference Laboratory to compare various procedures for WGS data analysis and to evaluate compatibility of results. Two different core genome multilocus sequence typing (cgMLST) schemes, different reference genomes in single nucleotide polymorphism (SNP) analysis and commercial as well as opensource software were compared. Correlation of allele distances from the different cgMLST approaches was high, ranging from 0.97 to 1, and unified thresholds yielded higher clustering concordance than schemespecific thresholds. The number of detected SNP differences could be increased up to a factor of 3.9 using a specific reference genome compared with a general one. Additionally, specific reference genomes improved comparability of SNP analysis results obtained using different software tools. The use of a closed or a draft specific reference genome did not make a difference. The harmonisation of WGS data analysis will finally guarantee seamless data exchange, but, in the meantime, knowledge on threshold values that lead to comparable clustering of isolates by different methods may improve communication between laboratories. We therefore established a translation code between commonly applied cgMLST and SNP methods based on optimised clustering concordances. This code can work as a first filter to identify WGS- based typing matches resulting from different methods, which opens up a new perspective for data exchange and thereby accelerates timecritical analyses, such as in outbreak investigations.Weniger anzeigen
Deutsche Bahn (DB) operates a large fleet of rolling stock (locomotives, wagons, and train sets) that must be combined into trains to perform rolling stock rotations. This train composition is a special characteristic of railway operations that distinguishes rolling stock rotation planning from the vehicle scheduling problems prevalent in other industries. DB models train compositions using hyperarcs. The resulting hypergraph models are addressed using a novel coarse-to-fine method that implements a hierarchical column generation over three levels of detail. This algorithm is the mathematical core of DB's fleet employment optimization (FEO) system for rolling stock rotation planning. FEO's impact within DB's planning departments has been revolutionary. DB has used it to support the company's procurements of its newest high-speed passenger train fleet and its intermodal cargo locomotive fleet for crossborder operations. FEO is the key to successful tendering in regional transport and to construction site management in daily operations. DB's planning departments appreciate FEO's high-quality results, ability to reoptimize (quickly), and ease of use. Both employees and customers benefit from the increased regularity of operations. DB attributes annual savings of 74 million euro, an annual reduction of 34,000 tons of CO2 emissions, and the elimination of 600 coupling operations in crossborder operations to the implementation of FEO.Weniger anzeigen
Background: Expensive optoelectronic systems, considered the gold standard, require a laboratory environment and the attachment of markers, and they are therefore rarely used in everyday clinical practice. Two-dimensional (2D) human pose estimations for clinical purposes allow kinematic analyses to be carried out via a camera-based smartphone app. Since clinical specialists highly depend on the validity of information, there is a need to evaluate the accuracy of 2D pose estimation apps.
Objective: The aim of the study was to investigate the accuracy of the 2D pose estimation of a mobility analysis app (Lindera-v2), using the PanopticStudio Toolbox data set as a reference standard. The study aimed to assess the differences in joint angles obtained by 2D video information generated with the Lindera-v2 algorithm and the reference standard. The results can provide an important assessment of the adequacy of the app for clinical use.
Methods: To evaluate the accuracy of the Lindera-v2 algorithm, 10 video sequences were analyzed. Accuracy was evaluated by assessing a total of 30,000 data pairs for each joint (10 joints in total), comparing the angle data obtained from the Lindera-v2 algorithm with those of the reference standard. The mean differences of the angles were calculated for each joint, and a comparison was made between the estimated values and the reference standard values. Furthermore, the mean absolute error (MAE), root mean square error, and symmetric mean absolute percentage error of the 2D angles were calculated. Agreement between the 2 measurement methods was calculated using the intraclass correlation coefficient (ICC[A,2]). A cross-correlation was calculated for the time series to verify whether there was a temporal shift in the data.
Results: The mean difference of the Lindera-v2 data in the right hip was the closest to the reference standard, with a mean value difference of –0.05° (SD 6.06°). The greatest difference in comparison with the baseline was found in the neck, with a measurement of –3.07° (SD 6.43°). The MAE of the angle measurement closest to the baseline was observed in the pelvis (1.40°, SD 1.48°). In contrast, the largest MAE was observed in the right shoulder (6.48°, SD 8.43°). The medians of all acquired joints ranged in difference from 0.19° to 3.17° compared with the reference standard. The ICC values ranged from 0.951 (95% CI 0.914-0.969) in the neck to 0.997 (95% CI 0.997-0.997) in the left elbow joint. The cross-correlation showed that the Lindera-v2 algorithm had no temporal lag.
Conclusions: The results of the study indicate that a 2D pose estimation by means of a smartphone app can have excellent agreement compared with a validated reference standard. An assessment of kinematic variables can be performed with the analyzed algorithm, showing only minimal deviations compared with data from a massive multiview system.Weniger anzeigen
Tectonic tremor has been observed at the roots of many fault systems around the Pacific rim, including convergent and transform plate boundaries. The extent to which deep tremor signals are prevalent along fault systems elsewhere, including the Mediterranean basin, has not yet been documented in detail. A body of evidence suggests that tremor triggered during the surface waves of teleseismic events may commonly occur where ambient tremor during episodic tremor and slip episodes occur, suggesting triggered tremor provides a useful tool to identify regions with ambient tremor. We perform a systematic search of triggered tremor associated with large teleseismic events between 2010 and 2020 at four major fault systems within the central-eastern Mediterranean basin, namely the Hellenic and Calabrian subduction zones, and the North Anatolian and Kefalonia transform faults. In addition, we search for ambient tremor during a slow slip event in the eastern Sea of Marmara along a secondary branch of the North Anatolian Fault, and two slow slip events beneath western Peloponnese (Hellenic Subduction Zone). We find no unambiguous evidence for deep triggered tremor, nor ambient tremor. The absence of triggered tremor at the Hellenic and Calabrian subduction zones supports an interpretation of less favorable conditions for tremorgenesis in the presence of old and cold slabs. The absence of tremor along the transform faults may be due to an absence of the conditions commonly promoting tremorgenesis in such settings, including high-fluid pressures and low-differential stresses between the down-dip limit of the seismogenic layer and the continental Moho.Weniger anzeigen
The realization of integrated quantum circuits requires precise on-chip control of charge carriers. Aiming at the coherent coupling of distant nanostructures at zero magnetic field, here we study the ballistic electron transport through two quantum point contacts (QPCs) in series in a three terminal configuration. We enhance the coupling between the QPCs by electrostatic focusing using a field effect lens. To study the emission and collection properties of QPCs in detail we combine the electrostatic focusing with magnetic deflection. Comparing our measurements with quantum mechanical and classical calculations we discuss generic features of the quantum circuit and demonstrate how the cohereWeniger anzeigen
Objectives: The aim of this article is to add a decisive new element to our current knowledge on how teaching sessions in have been conducted and recorded throughout Islamic history. This is done by editing a rare document containing the 'preliminary sama's' concerning readings of the Sunan by al-Daraqutni (d. 385 AH/995 AD), the preliminary sama's for the first part of al-Nasab by Zubayr b. Bakkar (d. 256 AH/870 AD), and a list of those attending a reading of a booklet containing hadiths by Dawud b. Rashid (d. 239 AH/853 AD). The secondary aim is to reflect on the identity of the writer of these preliminary lists and on the differences between these preliminary sama's (which we call 'awraq al-sama'') and the final sama' (the 'tibaq al-sama'').
Methodology: This study is based on the identification of a new 'genre' of documents ('preliminary sama's') produced in the course of teaching sessions. These documents are, in turn, philologically edited and then historically compared with other known documents produced in such sessions. A careful examination of these documentary practices allows us to understand the cultural logic of these documents.
Findings: Editing and studying these new documents adds to our understanding of such teaching sessions. The article thus argues the existence of a hitherto unknown documentary genre that is clearly distinct from the final sama' and constituted an earlier stage in the documentary practices of those involved in recording the attendance in teaching sessions.
Originality: The documents studied in this research have not previously been studied. Their publication thus adds entirely new primary sources to our field. More importantly, this study conceptualizes this type of document and thus significantly adds to our knowledge of teaching and learning practices throughout Islamic history.Weniger anzeigen
Background: Stereotactic radiosurgery (SRS) is an effective treatment for trigeminal neuralgia (TN). Nevertheless, a proportion of patients will experience recurrence and treatment-related sensory disturbances. In order to evaluate the predictors of efficacy and safety of image-guided non-isocentric radiosurgery, we analyzed the impact of trigeminal nerve volume and the nerve dose/volume relationship, together with relevant clinical characteristics.
Methods: Two-hundred and ninety-six procedures were performed on 262 patients at three centers. In 17 patients the TN was secondary to multiple sclerosis (MS). Trigeminal pain and sensory disturbances were classified according to the Barrow Neurological Institute (BNI) scale. Pain-free-intervals were investigated using Kaplan Meier analyses. Univariate and multivariate Cox regression analyses were performed to identify predictors.
Results: The median follow-up period was 38 months, median maximal dose 72.4 Gy, median target nerve volume 25 mm(3), and median prescription dose 60 Gy. Pain control rate (BNI I-III) at 6, 12, 24, 36, 48, and 60 months were 96.8, 90.9, 84.2, 81.4, 74.2, and 71.2%, respectively. Overall, 18% of patients developed sensory disturbances. Patients with volume ≥ 30 mm(3) were more likely to maintain pain relief (p = 0.031), and low integral dose (< 1.4 mJ) tended to be associated with more pain recurrence than intermediate (1.4-2.7 mJ) or high integral dose (> 2.7 mJ; low vs. intermediate: log-rank test, χ(2) = 5.02, p = 0.019; low vs. high: log-rank test, χ(2) = 6.026, p = 0.014). MS, integral dose, and mean dose were the factors associated with pain recurrence, while re-irradiation and MS were predictors for sensory disturbance in the multivariate analysis.
Conclusions: The dose to nerve volume ratio is predictive of pain recurrence in TN, and re-irradiation has a major impact on the development of sensory disturbances after non-isocentric SRS. Interestingly, the integral dose may differ significantly in treatments using apparently similar dose and volume constraints.Weniger anzeigen
Upconversion nanoparticles (UCNPs), consisting of NaYF4 doped with 18% Yb and 2% Er, were coated with microporous silica shells with thickness values of 7 +/- 2 and 21 +/- 3 nm. Subsequently, the negatively charged particles were functionalized with N-(6-aminohexyl)-3-aminopropyltrimethoxysilane (AHAPS), which provide a positive charge to the nanoparticle surface. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements revealed that, over the course of 24h, particles with thicker shells release fewer lanthanide ions than particles with thinner shells. However, even a 21 +/- 3 nm thick silica layer does not entirely block the disintegration process of the UCNPs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and cell cytometry measurements performed on macrophages (RAW 264.7 cells) indicate that cells treated with amino-functionalized particles with a thicker silica shell have a higher viability than those incubated with UCNPs with a thinner silica shell, even if more particles with a thicker shell are taken up. This effect is less significant for negatively charged particles. Cell cycle analyses with amino-functionalized particles also confirm that thicker silica shells reduce cytotoxicity. Thus, growing silica shells to a sufficient thickness is a simple approach to minimize the cytotoxicity of UCNPs.Weniger anzeigen