Saharan dust and ice nuclei over Central Europe

Surface measurements of aerosol and ice nuclei (IN) at a Central European mountain site during an episode of dust transport from the Sahara are presented. Ice nuclei were sampled by electrostatic precipitation on silicon wafers and were analyzed in an isothermal static vapor diffusion chamber. The transport of mineral dust is simulated by the Eulerian regional dust model DREAM. Ice nuclei and mineral dust are significantly correlated, in particular IN number concentration and aerosol surface area. The ice nucleating characteristics of the aerosol as analyzed with respect to temperature and supersaturation are similar during the dust episode than during the course of the year. This suggests that dust may be a main constituent of ice nucleating aerosols in Central Europe

The Significance of Vascular Alterations in Acute and Chronic Rejection for Vascularized Composite Allotransplantation.

Vascularized composite allotransplantation (VCA) has emerged as a useful reconstructive option for patients suffering from major tissue defects and functional deficits. While the technical feasibility has been optimized and more than 130 VCAs have been performed during the last two decades, hurdles such as acute and chronic allograft rejection, graft deterioration, and eventual functional impairment need to be addressed. Recently, chronic graft rejection and progressive failure have been linked to vascular alterations observed in the allografts. Graft vasculopathy (GV) may play a pivotal role in long-term graft deterioration. The understanding of the underlying pathophysiological processes and their initial triggers is of utmost importance in the prevention, attenuation, and therapy of GV. While there are reports on the etiology and development of GV in solid organ transplantation, there are limited data with respect to chronic rejection and GV in the realm of VCA. Nevertheless, recent reports from long-term VCA recipients suggest that GV could truly jeopardize allografts in the follow-up evaluation. Chronic rejection and GV include different entities and might have different pathways in distinct organs. Herein, we reviewed the current literature on vascular changes during both acute and chronic allograft rejection, with a focus on their clinical and translational significance for VCA

Abdominal, perineal, and genital soft tissue reconstruction with pedicled anterolateral thigh perforator flaps

Background Pedicled perforator flaps have become a contemporary alternative to muscle flaps for soft tissue reconstruction as they have reduced donor site morbidity, avoid the need for microsurgical transfer, and are versatile and reliable. The anterolateral thigh (ALT) flap was first introduced as a free flap and has since gained popularity as a pedicled flap. Here we review our experience using pedicled ALT flaps for regional soft tissue reconstruction. Methods We retrospectively reviewed all patients who underwent loco-regional soft tissue reconstruction using pedicled ALT flaps between March 2014 and October 2018, with the goal of identifying potential applications of pedicled ALT flaps. The following aspects of each case were reviewed: patient demographics, defect location and size, comorbidities such as previous radiotherapy, flap details, clinical follow-up, and postoperative complications. Results Our analysis demonstrates the versatility of pedicled ALT flaps in a variety of indications to successfully cover large abdominal, perineal, and genital soft tissue defects. Depending on the patient’s needs to achieve more bulk or stability in the reconstruction, the ALT flap was individually tailored with underlying muscle or fascia. The average follow-up was 7 months (range: 3–13 months). Conclusions Pedicled ALT flaps are a valuable reconstructive option for soft tissue defects located within the pedicle’s range, from the lower abdomen to the perianal region. These flaps are usually raised from a non-irradiated donor site and are sufficient for covering extensive soft tissue defects. Three-dimensional reconstruction of the defect using pedicled ALT flaps allows for anatomical function and minor donor sites

Atmospheric ice nuclei in the Eyjafjallajökull volcanic ash plume

We have sampled atmospheric ice nuclei (IN) and aerosol in Germany and in Israel during spring 2010. IN were analyzed by the static vapor diffusion chamber FRIDGE, as well as by electron microscopy. During the Eyjafjallajökull volcanic eruption of April 2010 we have measured the highest ice nucleus number concentrations (>600 l−1) in our record of 2 yr of daily IN measurements in central Germany. Even in Israel, located about 5000 km away from Iceland, IN were as high as otherwise only during desert dust storms. The fraction of aerosol activated as ice nuclei at −18 °C and 119% rhice and the corresponding area density of ice-active sites per aerosol surface were considerably higher than what we observed during an intense outbreak of Saharan dust over Europe in May 2008. Pure volcanic ash accounts for at least 53–68% of the 239 individual ice nucleating particles that we collected in aerosol samples from the event and analyzed by electron microscopy. Volcanic ash samples that had been collected close to the eruption site were aerosolized in the laboratory and measured by FRIDGE. Our analysis confirms the relatively poor ice nucleating efficiency (at −18 °C and 119% ice-saturation) of such "fresh" volcanic ash, as it had recently been found by other workers. We find that both the fraction of the aerosol that is active as ice nuclei as well as the density of ice-active sites on the aerosol surface are three orders of magnitude larger in the samples collected from ambient air during the volcanic peaks than in the aerosolized samples from the ash collected close to the eruption site. From this we conclude that the ice-nucleating properties of volcanic ash may be altered substantially by aging and processing during long-range transport in the atmosphere, and that global volcanism deserves further attention as a potential source of atmospheric ice nuclei

Predictors for limb amputation and reconstructive management in electrical injuries

BACKGROUND Electrical injuries follow a specific pathophysiology and may progressively damage both skin and deeper tissues, frequently ending in amputations. Type and timing of soft tissue reconstruction after electrical burns is crucial for proper outcome. The aim of this study was to assess surgical management and outcome of patients with electrical injuries treated at the Zurich Burn Center over the last 15 years, with emphasis on risk factors for amputation and reconstructive strategy. METHODS Patient charts were reviewed retrospectively to identify cases admitted at the Zurich Burns Center (2005-2019). Patient characteristics and surgical management, with a special focus on amputations, reconstruction and outcome were analyzed and risk factors for amputation were assessed. RESULTS Eighty-nine patients were identified and a total of 522 operations were performed. Escharotomy and fasciotomies were performed in 40.5% and 24.7% of cases, respectively, mainly at admission. The total amputation rate was 13.5% (23 amputations, 12 patients). Development of compartment syndrome, rhabdomyolysis, high myoglobin and CK blood levels, kidney failure, sepsis and respiratory complications during the course were related to higher risk of amputation (p < 0.001). Sixty-six flap-based reconstructions were performed (25% cases): 49 loco-regional flaps, 3 distant pedicled flaps, 14 free flaps. Two flaps were lost (flap failure rate 14%). Both flap losses occurred in cases of early reconstruction (within 5-21 days). CONCLUSIONS Electrical injuries are still cause of elevated morbidity and mortality, with high amputation rate. Predictors for amputation can support physicians in the surgical care and decision-making. Reconstruction remains challenging in this type of injury: the surgical management with early decompression, serial necrectomies and delayed early reconstruction remains the procedure of choice at our unit

Serum Selenium-Binding Protein 1 (SELENBP1) in Burn Injury: A Potential Biomarker of Disease Severity and Clinical Course

Oxidative stress, systemic inflammation, and metabolic derangements are hallmarks of burn pathophysiology. Severely burned patients are highly susceptible to infectious complications. Selenium-binding protein 1 (SELENBP1) modulates intracellular redox homeostasis, and elevated serum concentrations have been associated with adverse clinical outcomes in trauma patients. We hypothesized that serum SELENBP1 at hospital admission and during hospitalization may constitute a meaningful biomarker of disease severity and the clinical course in burn injury, with pulmonary infection as primary endpoint. To this end, we conducted a prospective cohort study that included 90 adult patients admitted to the Burn Center of the University Hospital Zurich, Switzerland. Patients were treated according to the local standard of care, with high-dose selenium supplementation during the first week. Serum SELENBP1 was determined at nine time-points up to six months postburn and the data were correlated to clinical parameters. SELENBP1 was initially elevated and rapidly declined within the first day. Baseline SELENBP1 levels correlated positively with the Abbreviated Burn Severity Index (ABSI) (R = 0.408; p < 0.0001). In multiple logistic regression, a higher ABSI was significantly associated with increased pulmonary infection risk (OR, 14.4; 95% CI, 3.2-88.8; p = 0.001). Similarly, baseline SELENBP1 levels constituted a novel but less accurate predictor of pulmonary infection risk (OR, 2.5; 95% CI, 0.7-8.9; p = 0.164). Further studies are needed to explore the additional value of serum SELENBP1 when stratifying patients with respect to the clinical course following major burns and, potentially, for monitoring therapeutic measures aimed at reducing tissue damage and oxidative stress

In-depth transcriptomic analysis of human retina reveals molecular mechanisms underlying diabetic retinopathy

Diabetic Retinopathy (DR) is among the major global causes for vision loss. With the rise in diabetes prevalence, an increase in DR incidence is expected. Current understanding of both the molecular etiology and pathways involved in the initiation and progression of DR is limited. Via RNA-Sequencing, we analyzed mRNA and miRNA expression profiles of 80 human post-mortem retinal samples from 43 patients diagnosed with various stages of DR. We found differentially expressed transcripts to be predominantly associated with late stage DR and pathways such as hippo and gap junction signaling. A multivariate regression model identified transcripts with progressive changes throughout disease stages, which in turn displayed significant overlap with sphingolipid and cGMP-PKG signaling. Combined analysis of miRNA and mRNA expression further uncovered disease-relevant miRNA/mRNA associations as potential mechanisms of post-transcriptional regulation. Finally, integrating human retinal single cell RNA-Sequencing data revealed a continuous loss of retinal ganglion cells, and Müller cell mediated changes in histidine and β-alanine signaling. While previously considered primarily a vascular disease, attention in DR has shifted to additional mechanisms and cell-types. Our findings offer an unprecedented and unbiased insight into molecular pathways and cell-specific changes in the development of DR, and provide potential avenues for future therapeutic intervention

Travelling on Graphs with Small Highway Dimension

We study the Travelling Salesperson (TSP) and the Steiner Tree problem (STP) in graphs of low highway dimension. This graph parameter was introduced by Abraham et al. [SODA 2010] as a model for transportation networks, on which TSP and STP naturally occur for various applications in logistics. It was previously shown [Feldmann et al. ICALP 2015] that these problems admit a quasi-polynomial time approximation scheme (QPTAS) on graphs of constant highway dimension. We demonstrate that a significant improvement is possible in the special case when the highway dimension is 1, for which we present a fully-polynomial time approximation scheme (FPTAS). We also prove that STP is weakly NP-hard for these restricted graphs. For TSP we show NP-hardness for graphs of highway dimension 6, which answers an open problem posed in [Feldmann et al. ICALP 2015]

Fast Ionic Conductivity in the Most Lithium-Rich Phosphidosilicate Li14SiP6.

Solid electrolytes with superionic conductivity are required as a main component for all-solid-state batteries. Here we present a novel solid electrolyte with three-dimensional conducting pathways based on "lithium-rich" phosphidosilicates with ionic conductivity of σ > 10-3 S cm-1 at room temperature and activation energy of 30-32 kJ mol-1 expanding the recently introduced family of lithium phosphidotetrelates. Aiming toward higher lithium ion conductivities, systematic investigations of lithium phosphidosilicates gave access to the so far lithium-richest compound within this class of materials. The crystalline material (space group Fm3m), which shows reversible thermal phase transitions, can be readily obtained by ball mill synthesis from the elements followed by moderate thermal treatment of the mixture. Lithium diffusion pathways via both tetrahedral and octahedral voids are analyzed by temperature-dependent powder neutron diffraction measurements in combination with maximum entropy method and DFT calculations. Moreover, the lithium ion mobility structurally indicated by a disordered Li/Si occupancy in the tetrahedral voids plus partially filled octahedral voids is studied by temperature-dependent impedance and 7Li NMR spectroscopy