A compact setup for behavioral studies measuring limb acceleration

Behavioral studies contribute largely to a broader understanding of human brain mechanisms and the process of learning and memory. An established method to quantify motor learning is the analysis of thumb activity. In combination with brain stimulation, the effect of various treatments on neural plasticity and motor learning can be assessed. So far, the setups for thumb abduction measurements employed consist of bulky amplifiers and digital-to-analog devices to record the data. We developed a compact hardware setup to measure acceleration data which can be integrated into a wearable, including a sensor board and a microcontroller board which can be connected to a PC via USB. Additionally, we provide two software packages including graphical user interfaces, one to communicate with the hardware and one to evaluate and process the data. This work demonstrates the construction and application of our setup at the example of thumb acceleration measurement with a custom made glove and its use for research. Using integrated circuits, the size of the measurement devices is reduced to this wearable. It is simple to construct and can be operated easily by non-technical staff.

Collinear Laser Spectroscopy of 2 ^{3}S_{1}→2 ^{3}P_{J} Transitions in Helium-like ^{12}C^{4+}

Transition frequencies and fine-structure splittings of the 2 ^{3}S_{1}→2 ^{3}P_{J} transitions in helium-like ^{12}C^{4+} were measured by collinear laser spectroscopy on a 1-ppb level. Accuracy is increased by more than 3 orders of magnitude with respect to previous measurements, enabling tests of recent nonrelativistic (NR) QED calculations including terms up to mα^{7}. Deviations between the theoretical and experimental values are within theoretical uncertainties and are ascribed to mα^{8} and higher-order contributions in the series expansion of the NR QED calculations. Finally, prospects for an all-optical charge radius determination of light isotopes are evaluated.

Nuclear Charge Radius of ^{26m}Al and Its Implication for V_{ud} in the Quark Mixing Matrix

Collinear laser spectroscopy was performed on the isomer of the aluminium isotope ^{26m}Al. The measured isotope shift to ^{27}Al in the 3s^{2}3p ^{2}P_{3/2}^{○}→3s^{2}4s ^{2}S_{1/2} atomic transition enabled the first experimental determination of the nuclear charge radius of ^{26m}Al, resulting in R_{c}=3.130(15)  fm. This differs by 4.5 standard deviations from the extrapolated value used to calculate the isospin-symmetry breaking corrections in the superallowed β decay of ^{26m}Al. Its corrected Ft value, important for the estimation of V_{ud} in the Cabibbo-Kobayashi-Maskawa matrix, is thus shifted by 1 standard deviation to 3071.4(1.0) s.

Determination of the Thermomigration Force on Adatoms

Thermal gradients in nanomaterials can cause surface mass transport phenomena. However, the atomic fluxes are challenging to quantify and the underlying atomic mechanisms are complex. Using low energy electron microscopy we have examined in operando, under a thermal gradient of 10^{4}  K/m, the thermomigration of supercooled Si(111)-1×1 advacancy islands. The islands move in the direction of the thermal gradient at 0.26±0.06  nm/s. This reveals that the adatoms move toward the cold region and the effective force exerted on Si adatoms is 1.4±0.4×10^{-8}  eV/nm. We quantify the heat of transport of Si atoms Q^{*}=1.2±0.4  eV and show that it corresponds to the combined effects of adatom creation at step edges and adatom diffusion on atomically flat terraces.

First Observation of Cyclotron Radiation from MeV-Scale e^{±} following Nuclear β Decay

We present an apparatus for detection of cyclotron radiation yielding a frequency-based β^{±} kinetic energy determination in the 5 keV to 2.1 MeV range, characteristic of nuclear β decays. The cyclotron frequency of the radiating β particles in a magnetic field is used to determine the β energy precisely. Our work establishes the foundation to apply the cyclotron radiation emission spectroscopy (CRES) technique, developed by the Project 8 Collaboration, far beyond the 18-keV tritium endpoint region. We report initial measurements of β^{-}'s from ^{6}He and β^{+}'s from ^{19}Ne decays to demonstrate the broadband response of our detection system and assess potential systematic uncertainties for β spectroscopy over the full (MeV) energy range. To our knowledge, this is the first direct observation of cyclotron radiation from individual highly relativistic β's in a waveguide. This work establishes the application of CRES to a variety of nuclei, opening its reach to searches for new physics beyond the TeV scale via precision β-decay measurements.

Bayesian approaches to include real-world data in clinical studies

Randomized clinical trials have been the mainstay of clinical research, but are prohibitively expensive and subject to increasingly difficult patient recruitment. Recently, there is a movement to use real-world data (RWD) from electronic health records, patient registries, claims data and other sources in lieu of or supplementing controlled clinical trials. This process of combining information from diverse sources calls for inference under a Bayesian paradigm. We review some of the currently used methods and a novel non-parametric Bayesian (BNP) method. Carrying out the desired adjustment for differences in patient populations is naturally done with BNP priors that facilitate understanding of and adjustment for population heterogeneities across different data sources. We discuss the particular problem of using RWD to create a synthetic control arm to supplement single-arm treatment only studies. At the core of the proposed approach is the model-based adjustment to achieve equivalent patient populations in the current study and the (adjusted) RWD. This is implemented using common atoms mixture models. The structure of such models greatly simplifies inference. The adjustment for differences in the populations can be reduced to ratios of weights in such mixtures. This article is part of the theme issue 'Bayesian inference: challenges, perspectives, and prospects'.

Residence times of groundwater along a flow path in the Great Artesian Basin determined by 81Kr, 36Cl and 4He: Implications for palaeo hydrogeology

Understanding the age distribution of groundwater can provide information on both the recharge history as well as the geochemical evolution of groundwater flow systems. Of the few candidates available that can be used to date old groundwater, ⁸¹Kr shows the most promise because its input function is constant through time and there are less sources and sinks to complicate the dating procedure in comparison to traditional tracers such as ³⁶Cl and ⁴He. In this paper we use ⁸¹Kr in a large groundwater basin to obtain a better understanding of the residence time distribution of an unconfined-confined aquifer system. A suite of environmental tracers along a groundwater flow path in the south-west Great Artesian Basin of Australia have been sampled. All age tracers (⁸⁵Kr, ³⁹Ar ¹⁴C, ⁸¹Kr, ³⁶Cl and ⁴He) display a consistent increase in groundwater age with distance from the recharge area indicating the presence of a connected flow path. Assuming that ⁸¹Kr is the most accurate dating technique the ³⁶Cl/Cl systematics was unravelled to reveal information on recharge mechanism and chloride concentration at the time of recharge. Current-day recharge occurs via ephemeral river recharge beneath the Finke River, while diffuse recharge is minor in the young groundwaters. Towards the end of the transect the influence of ephemeral recharge is less while diffuse recharge and the initial chloride concentration at recharge were higher.

β-Nuclear-Recoil Correlation from ^{6}He Decay in a Laser Trap

We report the first precise measurement of a β-recoil correlation from a radioactive noble gas (^{6}He) confined via a magneto-optical trap. The measurement is motivated by the search for exotic tensor-type contributions to the charged weak current. Interpreted as tensor currents with right-handed neutrinos, the measurements yield |C_{T}/C_{A}|^{2}≤0.022 (90% confidence limit, C.L.). On the other hand, for left-handed neutrinos the limits are 0.007<C_{T}/C_{A}<0.111 (90% C.L.). The sensitivity of the present measurement is mainly limited by experimental uncertainties in determining the time response properties and the distance between the atom cloud and the microchannel plate used for recoil ion detection.

Green‐Light Activatable BODIPY and Coumarin 5’‐Caps for Oligonucleotide Photocaging

We synthesized two green‐light activatable 5’‐caps for oligonucleotides based on the BODIPY and coumarin scaffold. Both bear an alkyne functionality allowing their use in numerous biological applications. They were successfully incorporated in oligonucleotides via solid‐phase synthesis. Copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) using a bisazide photo‐tether gave cyclic oligonucleotides that could be relinearized by activation with green light and were shown to exhibit high stability against exonucleases. Chemical ligation as another example for bioconjugation yielded oligonucleotides with an internal strand break site. Irradiation at 530 nm or 565 nm resulted in complete photolysis of both caging groups.

Robotic distal pancreatectomy, a novel standard of care? First benchmark values for surgical outcomes from 14 international expert centers

Objective

Robotic distal pancreatectomy (DP) is emerging as the preferred treatment for body and tail tumors of the pancreas. To enable conclusive comparisons with the standard open or laparoscopic approaches and robotic surgery among centers, novel benchmark outcome values are urgently needed. Therefore, the aim of this study was to identify benchmark values from expert centers beyond the learning curve.

Methods

This multicenter study analyzed outcomes from consecutive patients undergoing robotic DP for resectable malignant or benign lesions from 14 international expert centers. After the learning curve, defined as the first 10 cases of robotic DP, all consecutive patients were included from the start of the program up to June 2020 with a minimum follow-up of 1 year. Benchmark patients were those without significant comorbidities including obesity (BMI &gt;35 kg/m2) cardiac disease, chronic pulmonary disease.

Benchmark cutoff values were derived from the 75th or the 25th percentile of the median values of all benchmark centers.

Results

After reaching the learning curve, 289 (47%) of a total of 614 consecutive patients qualified as benchmark cases. The proportion of benchmark patients varied between 24%-64% per center. Benchmark cut-offs showed a low 6 month- postoperative mortality (&lt;0.6%), but high overall morbidity (&lt;58.3%). Benchmark cutoffs for operative time (&lt;300 min), conversion rate (&lt;3%), clinically relevant pancreatic fistulas (&lt;26.9%), CCI at 90-days (&lt;14.8), hospital stay (&lt;7 days) and readmission rate (&lt;22.9%). Benchmark cut-offs for complications remained unchanged after 3 months follow-up. For ductal adenocarcinoma benchmark cutoffs for number of lymph nodes were &gt; 19 with an R0 resection rate of &gt; 85%, and an overall survival of &gt;86% and &gt;52% after 1- and 5-years, respectively. Centers with a low cohort of benchmark patients (more difficult cases) had less clinically relevant pancreatic fistula (9% vs. 23%) and less overall complications (32% vs. 48%).

Conclusion

This benchmark analysis sets novel reference values for robotic DP, indicating favorable outcomes as compared to laparoscopic and open DP. These references values may serve for quality control of surgery in centers embarking in robotic DP, and include the procedure in the standard of care.

Controlling Coagulation in Blood with Red Light

Precise control of blood clotting and rapid reversal of anticoagulation are essential in many clinical situations. We were successful in modifying a thrombin-binding aptamer with a red-light photocleavable linker derived from Cy7 by Cu-catalyzed Click chemistry. We were able to show that we can successfully deactivate the modified aptamer with red light (660 nm) even in human blood-restoring the blood's natural coagulation capability.

Prehabilitation in patients undergoing colorectal surgery fails to confer reduction in overall morbidity: Results of a single-center, single-blinded, randomized controlled trial

Objective

Patients undergoing major surgery are prone to a functional decline due to the impairment of muscle, cardiorespiratory and neurological function as a response to surgical stress. Currently, there are solely weak recommendations in the ERAS protocol regarding the role of preoperative physical activity and prehabilitation in patients undergoing colorectal surgery. Studies in heterogenous cohorts showed contradictory results regarding the impact of prehabilitation on the reduction of postoperative complications. This randomized controlled trial assesses the impact of prehabilitation on postoperative complications in patients undergoing colorectal surgery within an ERAS protocol.

Methods

Between July 2016 and June 2019, a single-center, single-blinded , randomized controlled trial designed to test whether physiotherapeutic prehabilitation vs. normal physical activities prior to colorectal surgery may decrease morbidity within a stringent ERAS protocol was carried out. The primary endpoint was postoperative complications assessed by Comprehensive Complications Index (CCI®). Primary and secondary endpoints for both groups were analyzed and compared.

Results

A total of 107 patients (54 in the pERACS and 53 in the control cohort) were included in the study and randomized. Dropout rate was 4.5% (n = 5). Mean age (SD) in the control cohort was 65 (29–86) and 66 (24–90) years in pERACS cohort. The pERACS cohort contained more female patients (40% vs. 55%, p = 0.123) and a higher percentage of colorectal adenocarcinoma (32% vs. 23%, p = 0.384) although not significant. Almost all patients underwent minimally invasive surgery in both cohorts (96% vs 98%, p = 1.000). There was no between-cohort difference in the primary outcome measure 30-day Comprehensive Complications Index (15 [0 – 49] vs. 18 [0 – 43], p = 0.059). Secondary outcome as complications assessed according to Clavien-Dindo, length of hospital stay, reoperation rate and mortality showed no difference between both cohorts.

Conclusion

Routine physiotherapeutic prehabilitation cannot be recommended for patients undergoing colorectal surgery within an ERAS protocol (Grade A recommendation). To eliminate other confounders like geographical difference or difference in surgical technique, further multicenter RCTs are needed.

Mechanism and dynamics of fatty acid photodecarboxylase

Fatty acid photodecarboxylase (FAP) is a photoenzyme with potential green chemistry applications. By combining static, time-resolved, and cryotrapping spectroscopy and crystallography as well as computation, we characterized Chlorella variabilis FAP reaction intermediates on time scales from subpicoseconds to milliseconds. High-resolution crystal structures from synchrotron and free electron laser x-ray sources highlighted an unusual bent shape of the oxidized flavin chromophore. We demonstrate that decarboxylation occurs directly upon reduction of the excited flavin by the fatty acid substrate. Along with flavin reoxidation by the alkyl radical intermediate, a major fraction of the cleaved carbon dioxide unexpectedly transformed in 100 nanoseconds, most likely into bicarbonate. This reaction is orders of magnitude faster than in solution. Two strictly conserved residues, R451 and C432, are essential for substrate stabilization and functional charge transfer.

Ultrahigh vacuum packaging and surface cleaning for quantum devices

We describe design, implementation, and performance of an ultra-high vacuum (UHV) package for superconducting qubit chips or other surface sensitive quantum devices. The UHV loading procedure allows for annealing, ultra-violet light irradiation, ion milling, and surface passivation of quantum devices before sealing them into a measurement package. The package retains vacuum during the transfer to cryogenic temperatures by active pumping with a titanium getter layer. We characterize the treatment capabilities of the system and present measurements of flux tunable qubits with an average T₁ = 84 µs and T₂ ^echo=134μs after vacuum-loading these samples into a bottom loading dilution refrigerator in the UHV-package.

Urbanisation is a main driver for Aedes aegypti dynamics and arboviral risk in Côte d’Ivoire

Background

Aedes mosquito-borne arboviruses have (re-)emerged and caused considerable public health concerns in major sub-Saharan African cities subjected to rapid urbanisation. We assessed the effects of urbanisation on Aedes aegypti dynamics and biting pattern, and the risk of transmission of yellow fever (YF) and dengue (DEN) viruses along urban-rural gradient in Côte d'Ivoire.

Methods

We collected Aedes mosquitoes as eggs, larvae/pupae, and adults seasonally in urban, suburban and rural areas using ovitrap, larval survey and human-baited double net trap methods from January 2015 to December 2016. We sampled household data and characterised Aedes larval breeding sites. Ae. aegypti indices and biting rates were compared by area.

Results

Ae. aegypti was the most abundant species in all areas. It showed higher abundance in urban areas (n = 26,072; 99.4%). Larval indices were associated with human activities, including waste and water management. Tires and discarded containers were the most productive breeding sites in all areas. Household water receptacles displayed high Aedes-positive rate (23.6%) in urban areas. Positive ovitrap index was higher in urban (53.5%) compared to suburban (43.1%) and rural (29.7%). Stegomyia indices were highest in urban followed by suburban and rural areas, with respective house index of 67.2, 51.4 and 27.8, container index of 57.1, 43.5 and 19.7, and Breteau index of 95.2, 78.9 and 8.8. Biting rate was 4.3 and 2.7-fold higher in urban (83.5 bite/person/day) and suburban (52.1 bite/person/day) compared to rural (19.4 bite/person/day), respectively. Ae. aegypti indices were higher during rainy seasons.

Conclusions

In Côte d'Ivoire, urbanisation raised Ae. aegypti abundance and biting rate. As a result, YF and DEN risk indices were above WHO-established epidemic thresholds in urban area thus exposing local communities to high risk of getting diseases. Integrated community-based vector control programs should be applied to reduce arboviral risk.

Key messages

Urbanisation raises Aedes aegypti abundance and arboviral disease risk in Côte d’Ivoire. Integrated community clean-up actions are required to control Aedes vectors.

ABCG2 influence on the efficiency of photodynamic therapy in glioblastoma cells

BACKGROUND

Photodynamic therapy with 5-aminolevulinic acid (5-ALA PDT) is a promising novel therapeutic approach in the therapy of malignant brain tumors. 5-ALA occurs as a natural precursor of protoporphyrin IX (PpIX), a tumor-selective photosensitizer. The ATP-binding cassette transporter ABCG2 plays a physiologically significant role in porphyrin efflux from living cells. ABCG2 is also associated with stemness properties. Here we investigate the role of ABCG2 on the susceptibility of glioblastoma cells to 5-ALA PDT.

METHODS

Accumulation of PpIX in doxycycline-inducible U251MG glioblastoma cells with or without induction of ABCG2 expression or ABCG2 inhibition by KO143 was analyzed using flow cytometry. In U251MG cells, ABCG2 was inducible by doxycycline after stable transfection with a tet-on expression plasmid. U251MG cells with high expression of ABCG2 were enriched and used for further experiments (sU251MG-V). PDT was performed on monolayer cell cultures by irradiation with laser light at 635 nm.

RESULTS

Elevated levels of ABCG2 in doxycycline induced sU251MG-V cells led to a diminished accumulation of PpIX and higher light doses were needed to reduce cell viability. By inhibiting the ABCG2 transporter with the efficient and non-toxic ABCG2 inhibitor KO143, PpIX accumulation and PDT efficiency could be strongly enhanced.

CONCLUSION

Glioblastoma cells with high ABCG2 expression accumulate less photosensitizer and require higher light doses to be eliminated. Inhibition of ABCG2 during photosensitizer accumulation and irradiation promises to restore full susceptibility of this crucial tumor cell population to photodynamic treatment.

Investigation of the susceptibility of Candida auris and Candida albicans to chemical disinfectants using European Standards EN 13624 and EN 16615

BACKGROUND

Since the first appearance of Candida auris in 2009, this yeast has become a relevant pathogen in the clinical field. C. auris has been detected on various surfaces in health facilities, and is therefore a target for appropriate disinfection procedures. Preventive measures have to be implemented based on disinfectants with proven efficacy against C. auris.

AIM

The chemical tolerance of C. auris was compared with the surrogate test organism Candida albicans as established in the European standards (EN). In this way, conclusions will be drawn as to whether the disinfectants tested according to EN 13624 and EN 16615 are at least equally effective against C. auris.

METHODS

The chemical susceptibility of C. auris and C. albicans was investigated using standardized EN test protocols. EN 13624 and EN 16615 were used in this study to examine two commercially available surface disinfectants based on alcohol and quaternary ammonium compounds (QACs), respectively. In addition, the survival rates of the two yeast species were studied on a defined test surface simulating practical conditions.

FINDINGS

In comparison with C. albicans, C. auris was found to be significantly more susceptible to the alcohol- and QAC-based disinfectants used in this study. C. albicans was found to be more tolerant to drying on the test surface in EN 16615, yielding higher recovery rates.

CONCLUSION

C. albicans is a suitable surrogate test organism when targeting yeasticidal efficacy, which, based on EN 13624 and EN 16615, includes efficacy against the human pathogen C. auris.

Atomic Transport in Au-Ge Droplets: Brownian and Electromigration Dynamics

The deposition of Au on Ge(111)-sqrt[3]×sqrt[3]-Au above the eutectic temperature results in the formation of AuGe liquid droplets that reach the liquidus composition by digging a hole in the Ge substrate. The combination of low-energy electron microscopy and atomic force microscopy measurements shows that AuGe droplets randomly migrate or electromigrate under an applied electric current dragging their underneath hole. The droplet motion is due to a mass transport phenomenon based on Ge dissolution at the droplet front and Ge crystallization at its rear. At high temperature the mass transport is limited by attachment or detachment at the solid-liquid interface and the activation energy is 1.05±0.3  eV. At low temperature the effective activation energy increases as a function of the droplet radius. This behavior is attributed to the nucleation of 2D layers at the faceted liquid-solid interface.

Introducing LNAzo: More Rigidity for Improved Photocontrol of Oligonucleotide Hybridization

Oligonucleotide-based therapeutics have made rapid progress in clinical treatment of a variety of disease indications. Since most therapeutic oligonucleotides serve more than just one function and tend to have a prolonged lifetime, spatio-temporal control of these functions would be desirable. Photoswitches like azobenzene have proven themselves as useful tools in this matter. Upon irradiation, the photoisomerization of the azobenzene moiety causes destabilization in adjacent base pairs, leading to a decreased hybridization affinity. Since the way the azobenzene is incorporated in the oligonucleotide is of utmost importance, we synthesized locked azobenzene C-nucleosides and compared their photocontrol capabilities to established azobenzene C-nucleosides in oligonucleotide test-sequences by means of fluorescence-, UV/Vis-, and CD-spectroscopy.

Phosphodiester photo-tethers for the (multi-)cyclic conformational caging of oligonucleotides

The ability to address the function of oligonucleotides with light is highly desirable since they are often used experimentally in the regulation of biological processes that need to be controlled in time, space and activation level. Here we present an extension of our initial approach of using photo-tethers that force single strands of nucleic acids into a circle, thus making them unable to form a duplex with a complementary DNA- or RNA-strand. Due to the persistence length a single strand can form a circle of, for example, 30 nucleotides, but a duplex cannot. We show that these new photo-tethers can also be easily installed on the phosphodiester backbone. This simplifies the approach considerably and leads to temporarily inhibited oligonucleotides that can only form a duplex after linearization by photoactivation.

Intelligent Packaging in the Food Sector: A Brief Overview

The trend towards sustainability, improved product safety, and high-quality standards are important in all areas of life sciences. In order to satisfy these requirements, intelligent packaging is used in the food sector. These systems can monitor permanently the quality status of a product and share the information with the customer. In this way, food waste can be reduced and customer satisfaction can be optimized. Depending on the product, different types of intelligent packaging technologies are used and discussed in this review. The three main groups are: data carriers, indicators, and sensors. At this time, they are not that widespread, but their potential is already known. In which areas intelligent packaging should be implemented, how the systems work, and which values they offer are dealt in this review.

Do bednets including piperonyl butoxide offer additional protection against populations of Anopheles gambiae s.l. that are highly resistant to pyrethroids? An experimental hut evaluation in Burkina Fasov

Malaria control is dependent on the use of longlasting insecticidal nets (LLINs) containing pyrethroids. A new generation of LLINs containing both pyrethroids and the synergist piperonyl butoxide (PBO) has been developed in response to increasing pyrethroid resistance in African malaria vectors, but questions remain about the performance of these nets in areas where levels of pyrethroid resistance are very high. This study was conducted in two settings in southwest Burkina Faso, Vallée du Kou 5 and Tengrela, where Anopheles gambiae s.l. (Diptera: Culicidae) mortality rates in World Health Organization (WHO) discriminating dose assays were < 14% for permethrin and < 33% for deltamethrin. When mosquitoes were pre-exposed to PBO in WHO tube assays, mortality rates increased substantially but full susceptibility was not restored. Molecular characterization revealed high levels of kdr alleles and elevated levels of P450s previously implicated in pyrethroid resistance. In cone bioassays and experimental huts, PBO LLINs outperformed the pyrethroid-only equivalents from the same manufacturers. Blood feeding rates were 1.6-2.2-fold lower and mortality rates were 1.69-1.78-fold greater in huts with PBO LLINs vs. non-PBO LLINs. This study indicates that PBO LLINs provide greater personal and community-level protection than standard LLINs against highly pyrethroid-resistant mosquito populations.

Standardized microgel beads as elastic cell mechanical probes

Cell mechanical measurements are gaining increasing interest in biological and biomedical studies. However, there are no standardized calibration particles available that permit the cross-comparison of different measurement techniques operating at different stresses and time-scales. Here we present the rational design, production, and comprehensive characterization of poly-acrylamide (PAAm) microgel beads mimicking size and overall mechanics of biological cells. We produced mono-disperse beads at rates of 20-60 kHz by means of a microfluidic droplet generator, where the pre-gel composition was adjusted to tune the beads' elasticity in the range of cell and tissue relevant mechanical properties. We verified bead homogeneity by optical diffraction tomography and Brillouin microscopy. Consistent elastic behavior of microgel beads at different shear rates was confirmed by AFM-enabled nanoindentation and real-time deformability cytometry (RT-DC). The remaining inherent variability in elastic modulus was rationalized using polymer theory and effectively reduced by sorting based on forward-scattering using conventional flow cytometry. Our results show that PAAm microgel beads can be standardized as mechanical probes, to serve not only for validation and calibration of cell mechanical measurements, but also as cell-scale stress sensors.

Statistics for real-time deformability cytometry: Clustering, dimensionality reduction, and significance testing

Real-time deformability (RT-DC) is a method for high-throughput mechanical and morphological phenotyping of cells in suspension. While analysis rates exceeding 1000 cells per second allow for a label-free characterization of complex biological samples, e.g., whole blood, data evaluation has so far been limited to a few geometrical and material parameters such as cell size, deformation, and elastic Young's modulus. But as a microscopy-based technology, RT-DC actually generates and yields multidimensional datasets that require automated and unbiased tools to obtain morphological and rheological cell information. Here, we present a statistical framework to shed light on this complex parameter space and to extract quantitative results under various experimental conditions. As model systems, we apply cell lines as well as primary cells and highlight more than 11 parameters that can be obtained from RT-DC data. These parameters are used to identify sub-populations in heterogeneous samples using Gaussian mixture models, to perform a dimensionality reduction using principal component analysis, and to quantify the statistical significance applying linear mixed models to datasets of multiple replicates.

Design of nanostructured hybrid materials: twin polymerization of urethane-based twin prepolymers

Organic–inorganic hybrid materials with urethane functionalities were obtained by simultaneous twin polymerization of twin prepolymers in combination with the ideal twin monomer 2,2′-spirobi[4H-1,3,2-benzodioxasiline]. The twin prepolymers consist of a urethane-based prepolymer with reactive terminal groups which can react during the twin polymerization process. Nanostructured hybrid materials with integrated dialkylsiloxane crosslinked urethane structures, phenolic resin and SiO₂ are obtained in a one pot process. The effects of the polymerization temperature as well as those of various catalysts and reagent ratios on the polymerization behavior were investigated. The molecular structures of the obtained materials were determined by ¹³C- and ²⁹Si-{¹H}-CP-MAS NMR spectroscopies. HAADF-STEM-measurements were performed to prove the distribution of silicon in the hybrid material.

Organic–inorganic hybrid materials with urethane functionalities were obtained by simultaneous twin polymerization of twin prepolymers in combination with the twin monomer 2,2′-spirobi[4H-1,3,2-benzodioxasiline].

Whole genome microarray expression analysis in blood identifies pathways linked to signs and symptoms of a patient with hypercalprotectinaemia and hyperzincaemia

A child, 2 years with the 'hypercalprotectinaemia with hyperzincaemia' clinical syndrome, presented with atypical symptoms and signs, notably persistent fever of approximately 38°C, thrombocythaemia of > 700 × 10⁹ /l and a predominance of persistent intestinal symptoms. In an effort to find a cure by identifying the dysregulated pathways we analysed whole-genome mRNA expression by the Affymetrix HG U133 Plus 2·0 array in blood on three occasions 3-5 months apart. Major up-regulation was demonstrated for the Janus kinase/signal transducer and activators of transcription (JAK/STAT) pathway including, in particular, CD177, S100A8, S100A9 and S100A12, accounting for the thrombocytosis; a large number of interleukins, their receptors and activators, accounting for the febrile apathic state; and the high mobility group box 1 (HMBG1) gene, possibly accounting for part of the intestinal symptoms. These results show that gene expression array technology may assist the clinician in the diagnostic work-up of individual patients with suspected syndromal states of unknown origin, and the expression data can guide the selection of optimal treatment directed at the identified target pathways.

Spatial inhomogeneity and temporal dynamics of a 2D electron gas in interaction with a 2D adatom gas

Fundamental interest for 2D electron gas (2DEG) systems has been recently renewed with the advent of 2D materials and their potential high-impact applications in optoelectronics. Here, we investigate a 2DEG created by the electron transfer from a Ag adatom gas deposited on a Si(111) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{{\bf{3}}}{\boldsymbol{\times }}\sqrt{{\bf{3}}}$$\end{document}3×3-Ag surface to an electronic surface state. Using low-energy electron microscopy (LEEM), we measure the Ag adatom gas concentration and the 2DEG-induced charge transfer. We demonstrate a linear dependence of the surface work function change on the Ag adatom gas concentration. A breakdown of the linear relationship is induced by the occurrence of the Ag adatom gas superstructure identified as Si(111) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sqrt{{\bf{21}}}{\boldsymbol{\times }}\sqrt{{\bf{21}}}$$\end{document}21×21-Ag only observed below room temperature. We evidence below room temperature a confinement of the 2DEG on atomic terraces characterised by spatial inhomogeneities of the 2DEG-induced charge transfer along with temporal fluctuations. These variations mirror the Ag adatom gas concentration changes induced by the growth of 3D Ag islands and the occurrence of an Ehrlich-Schwoebel diffusion barrier of 155 ± 10 meV.

Mechanical properties of non-centrosymmetric CePt3Si and CePt3B

Elastic moduli, hardness (both at room temperature) and thermal expansion (4.2-670 K) have been experimentally determined for polycrystalline CePt₃Si and its prototype compound CePt₃B as well as for single-crystalline CePt₃Si. Resonant ultrasound spectroscopy was used to determine elastic properties (Young's modulus E and Poisson's ratio ν) via the eigenfrequencies of the sample and the knowledge of sample mass and dimensions. Bulk and shear moduli were calculated from E and ν, and the respective Debye temperatures were derived. In addition, ab initio DFT calculations were carried out for both compounds. A comparison of parameters evaluated from DFT with those of experiments revealed, in general, satisfactory agreement. Positive and negative thermal expansion values obtained from CePt₃Si single crystal data are fairly well explained in terms of the crystalline electric field model, using CEF parameters derived recently from inelastic neutron scattering. DFT calculations, in addition, demonstrate that the atomic vibrations keep almost unaffected by the antisymmetric spin-orbit coupling present in systems with crystal structures having no inversion symmetry. This is opposite to electronic properties, where the antisymmetric spin-orbit interaction has shown to distinctly influence features like the superconducting condensate of CePt₃Si.

Light-inducible antimiR-92a as a therapeutic strategy to promote skin repair in healing-impaired diabetic mice

MicroRNAs (miRs) are small non-coding RNAs that post-transcriptionally control gene expression. Inhibition of miRs by antisense RNAs (antimiRs) might be a therapeutic option for many diseases, but systemic inhibition can have adverse effects. Here we show that light-activatable antimiRs efficiently and locally restricted target miR activity in vivo. We use an antimiR-92a and establish a therapeutic benefit in diabetic wound healing. AntimiR-92a is modified with photolabile protecting groups, so called ‘cages'. Irradiation activates intradermally injected caged antimiR-92a without substantially affecting miR-92a expression in other organs. Light activation of caged antimiR-92a improves healing in diabetic mice to a similar extent as conventional antimiRs and derepresses the miR-92a targets Itga5 and Sirt1, thereby regulating wound cell proliferation and angiogenesis. These data show that light can be used to locally activate therapeutically active antimiRs in vivo.

Inhibition of microRNAs using antimiRs is a potential therapeutic option for a number of diseases, but systemic inhibition may cause adverse effects. Here the authors develop light-activated antimiRs directed against miR-92a, and show localized inhibition in the skin and improved wound healing in diabetic mice.

Adaptive Optiken – Möglichkeiten für die Diagnostik hereditärer Netzhauterkrankungen

Adaptive Optiken (AO) stellen eine technologische Schlüsselinnovation für die Bildgebung in der Ophthalmologie dar. Mit AO ausgestattete Ophthalmoskope erlauben es, die mikroskopische Netzhautstruktur nicht invasiv und auf zellulärer Ebene darzustellen. So kann die strukturelle Integrität der retinalen Nervenfaserschicht, des perifovealen Kapillarnetzwerks, einzelner Stäbchen- und Zapfenphotorezeptoren und des zellulären Mosaiks des retinalen Pigmentepithels in vivo beobachtet werden. Für die Beurteilung des Verlaufs von Netzhauterkrankungen, einer möglichen pharmakologischen Intervention und die Entschlüsselung der zugrunde liegenden physiologischen Mechanismen bedeutet dies eine völlig neue Untersuchungsebene. Insbesondere monogenetische Erkrankungen liegen im Fokus der aktuellen Forschung. Zum einen können Rückschlüsse auf einzelne Pathologien anderer multifaktorieller Netzhauterkrankungen gezogen und so die zugrundeliegenden physiologischen Mechanismen bzw. Verläufe genauer untersucht werden (Modellerkrankung). Zum anderen werden auch im Hinblick auf aktuelle und kommende Interventionen (u. a. Gentherapie) neuartige und zuverlässige Endpunkte zur Interpretation des Therapieerfolgs notwendig. Erste kommerzielle AO-Ophthalmoskope sind für den klinischen Einsatz erhältlich, und die Zahl mit AO untersuchter Netzhautpathologien wächst zunehmend. Für eine zellgenaue Struktur-Funktions-Korrelation kann jüngstens eine AO-basierte Mikrostimulationstechnologie eingesetzt werden.