Synthesis and Characterization of Single Crystal Zircon-Hafnon Zr(1-x)Hf(x)SiO4 Solid Solutions and the Comparison with the Reaction Products of a TEOS-Based Hydrothermal Route.

Two synthesis routes of the zircon-hafnon solid solution series were carried out. The high-temperature route uses the growth of single crystals via a flux mixture that has been cooled down slowly from 1400 °C over 4 weeks. The reaction products were colorless and idiomorphic without byproducts. The hydrothermal tetraethoxysilane (TEOS)-based route represents the low-temperature method at 200 °C for approximately 7 days. The hydrothermal route yielded a white powder and scanning electron microscopy analysis thereof did not reveal any specific idiomorphic properties. However, the synthesis also featured some byproducts besides the zircon-hafnon solid solutions. Thermogravimetric analysis coupled with differential scanning calorimetry, and mass spectroscopy indicated, that hydrothermal reaction products feature the presence of organic residues originating from the starting materials. However, a specific dependency on the hafnium content could not be observed due to the data scatter. Infrared (IR) analysis revealed the presence of Zr/Hf-oxides. The structural characterization demonstrated that properties change constantly with the hafnium amount, however, gradual variations of some properties related to the composition of the solid solution series depend in part on the synthesis route, considering the c/a ratio and IR modes. Furthermore, analyses of the single crystals by Raman spectroscopy and µXRF suggested a nonequilibrated crystal growth based on the starting composition.

Benthic microbial biogeographic trends in the North Sea are shaped by an interplay of environmental drivers and bottom trawling effort.

Microbial composition and diversity in marine sediments are shaped by environmental, biological, and anthropogenic processes operating at different scales. However, our understanding of benthic microbial biogeography remains limited. Here, we used 16S rDNA amplicon sequencing to characterize benthic microbiota in the North Sea from the top centimeter of 339 sediment samples. We utilized spatially explicit statistical models, to disentangle the effects of the different predictors, including bottom trawling intensity, a prevalent industrial fishing practice which heavily impacts benthic ecosystems. Fitted models demonstrate how the geographic interplay of different environmental and anthropogenic drivers shapes the diversity, structure and potential metabolism of benthic microbial communities. Sediment properties were the primary determinants, with diversity increasing with sediment permeability but also with mud content, highlighting different underlying processes. Additionally, diversity and structure varied with total organic matter content, temperature, bottom shear stress and bottom trawling. Changes in diversity associated with bottom trawling intensity were accompanied by shifts in predicted energy metabolism. Specifically, with increasing trawling intensity, we observed a transition toward more aerobic heterotrophic and less denitrifying predicted metabolism. Our findings provide first insights into benthic microbial biogeographic patterns on a large spatial scale and illustrate how anthropogenic activity such as bottom trawling may influence the distribution and abundances of microbes and potential metabolism at macroecological scales.

Predicting the effects of COVID-19 related interventions in urban settings by combining activity-based modelling, agent-based simulation, and mobile phone data.

Epidemiological simulations as a method are used to better understand and predict the spreading of infectious diseases, for example of COVID-19. This paper presents an approach that combines a well-established approach from transportation modelling that uses person-centric data-driven human mobility modelling with a mechanistic infection model and a person-centric disease progression model. The model includes the consequences of different room sizes, air exchange rates, disease import, changed activity participation rates over time (coming from mobility data), masks, indoors vs. outdoors leisure activities, and of contact tracing. It is validated against the infection dynamics in Berlin (Germany). The model can be used to understand the contributions of different activity types to the infection dynamics over time. It predicts the effects of contact reductions, school closures/vacations, masks, or the effect of moving leisure activities from outdoors to indoors in fall, and is thus able to quantitatively predict the consequences of interventions. It is shown that these effects are best given as additive changes of the reproduction number R. The model also explains why contact reductions have decreasing marginal returns, i.e. the first 50% of contact reductions have considerably more effect than the second 50%. Our work shows that is is possible to build detailed epidemiological simulations from microscopic mobility models relatively quickly. They can be used to investigate mechanical aspects of the dynamics, such as the transmission from political decisions via human behavior to infections, consequences of different lockdown measures, or consequences of wearing masks in certain situations. The results can be used to inform political decisions.

Prevalence of visceral artery involvement in patients with peripheral artery disease found on run-off MRA.

BACKGROUND: In patients with peripheral artery disease (PAD), run-off MR-angiography (MRA) is a commonly performed diagnostic test to obtain high-resolution images for evaluation of the arterial system from the aorta through the distal run-off vessels. The aim of this study was to investigate the prevalence of visceral artery involvement (VAI) in patients with PAD and leg symptoms examined with run-off MRA. METHODS: We retrospectively analyzed 145 patients (median age 68 years, range 27-91) who underwent MRA due to known or suspected PAD at our institution between 2012 and 2018. MRA examinations were re-evaluated for visceral artery stenosis. Patient dossiers were reviewed to determine cardiovascular risk factors, kidney function and Fontaine stage of PAD. RESULTS: Involvement of at least one visceral artery with ≥ 50% diameter stenosis was found in 72 (50%) patients. There were no differences in age, gender, MRA indication, Fontaine stage, levels of C-reactive protein (CRP), cardiovascular risk factors or vascular comorbidities between patients with and without VAI. Renal artery (RA) involvement with ≥ 50% diameter stenosis was observed in 28 (20%) of patients. Patients with involvement of the RA were more likely to suffer from hypertension (79 vs. 54%, p = 0.019) and reduced renal function (glomerular filtration rate 70 vs. 88 mL/min/1.73m2, p = 0.014). CONCLUSION: Visceral artery stenosis can be seen in half of patients with known or suspected PAD and leg symptoms on run-off MRA. Investigating for RA stenosis in patients with PAD and hypertension and/or impaired renal function may have high diagnostic yield.

Extravascular findings on run-off MR angiography: frequency, location and clinical significance.

OBJECTIVES: The aim of this study was to analyze the prevalence, location and clinical relevance of extravascular findings (EVFs) on magnetic resonance angiography (MRA) of the run-off vasculature. METHODS: In this retrospective study, we analyzed run-off MRAs of 194 consecutive patients (45 women and 149 men, median age 68 years, IQR 58-74 years). Our patient cohort consisted predominantly of individuals with known (n = 165, 85%) or suspected (n = 15, 8%) peripheral artery disease (PAD). All MRA examinations were performed between 2012 and 2018 on a 3 Tesla MRI scanner using a standardized protocol. Two radiologists re-evaluated the MRA images to identify EVFs, which were classified into findings with major (category I), moderate (category II) and minor (category III) clinical significance. RESULTS: A total of 501 EVFs were found in 172 of the 194 patients (89%). Twenty-seven findings (5%) were assigned to category I, 189 (38%) to category II and 285 (57%) to category III. 23 of 194 patients (12%) had at least one EVF with major clinical relevance (category I). Most of the 27 category I EVFs were observed in the soft tissues (n = 13, 48%). The remaining category I EVFs were found in the musculoskeletal (n = 7, 26%), urogenital (n = 4, 15%), lymphatic (n = 2, 7%) and gastrointestinal (n = 1, 4%) system. The majority of the category I EVFs were infectious (n = 14, 52%) or neoplastic (n = 10, 37%) pathologies. CONCLUSIONS: Clinically relevant EVF can be encountered frequently on run-off MRA examinations. These results illustrate the importance of evaluating all organ systems when reporting MRA examinations, despite the clinical focus being the patients' vascular status.

Concomitant chronic venous insufficiency in patients with peripheral artery disease: insights from MR angiography.

OBJECTIVES: The clinical presentation of peripheral artery disease (PAD) and chronic venous insufficiency (CVI) can overlap and the conditions may co-exist. The purpose of our study was to investigate the prevalence and clinical significance of concomitant CVI in patients with PAD examined with run-off MR angiography (MRA). METHODS: We analysed 180 patients (median age 69 years, range 27 to 91) with known or suspected PAD who underwent MRA at our institution between 2012 and 2018. MRA datasets were re-evaluated for manifestations of CVI. Electronic charts were reviewed to analyse whether diagnosis of CVI was documented and to determine Fontaine stage of PAD. RESULTS: Evidence of possible CVI on MRA was found in 38 (21%) patients. Only seven (18%) of these patients had a documented diagnosis of CVI. Patients with co-existing PAD and CVI were more likely obese (median BMI 29.7 vs. 26.3 kg/m2, p = 0.001) and diabetic (55 vs. 35%, p = 0.039) than patients without CVI. The frequency of concomitant CVI manifestations decreased from distal to proximal with the lower leg affected in all 38 patients and the thigh in 17 patients (45%). Patients with co-existing PAD and CVI were more likely to have a clinical diagnosis of stage IV PAD than patients without co-existing CVI (57% vs. 34%, relative risk 1.68, p = 0.018). CONCLUSIONS: Signs of possible concomitant CVI can be seen in approximately one-fifth of patients with known or suspected PAD examined with run-off MRA. If present, these findings should be reported since CVI may mimic or contribute to symptoms attributed to PAD. KEY POINTS: • In total, 21% of patients with PAD patients examined with MR angiography show signs of possible co-existing CVI. • Patients with co-existing CVI were 1.7-fold more likely to have a clinical diagnosis of stage IV PAD. • Our data also showed that co-existing chronic venous insufficiency is under-diagnosed in patients with PAD.

Giant brachial artery aneurysm as a rare complication of a dialysis shunt.

Our patient exhibited a large tumor on his right upper arm where his former dialysis access site had been. X-ray, Doppler ultrasound, and magnetic resonance imaging scan could not fully reveal the nature of that tumor. Eventually, a surgical approach showed a giant aneurysm of the inflowing brachial artery to a partially obliterated arteriovenous fistula. This case highlights the importance of ongoing care for patients with arteriovenous shunts. Even arteriovenous fistulas, that are obliterated or no longer in use, can, especially when immunosuppressant therapy and other vascular risk factors are added to the overall cardiovascular risk, transform and endanger the health of our patients.

Analysis of the Secondary Phases Formed by Corrosion of U3Si2-Al Research Reactor Fuel Elements in the Presence of Chloride Rich Brines.

Corrosion experiments with non-irradiated U3Si2-Al research reactor fuel samples were carried out in synthetic MgCl2-rich brine to identify and quantify the secondary phases because depending on their composition and on their amount, such compounds can act as a sink for the radionuclide release in final repositories. Within the experimental period of 100 days at 90 °C and anoxic conditions the U3Si2-Al fuel sample was completely disintegrated. The obtained solids were subdivided into different grain size fractions and non-ambient X-ray diffraction (XRD) was applied for their qualitative and quantitative phase analysis. The secondary phases consist of lesukite (aluminum chloro hydrate) and layered double hydroxides (LDH) with varying chemical compositions. Furthermore, iron, residues of non-corroded nuclear fuel (U3Si2), iron oxy hydroxides and chlorides were also observed. In addition to high amorphous contents (>45 wt %) hosting the uranium, the quantitative phase analysis showed, that LDH compounds and lesukite were the major crystalline phases. Scanning electron microscopy (SEM) and energy dispersive -Xray spectroscopy (EDS) confirmed the results of the XRD analysis. Elemental analysis revealed that U and Al were concentrated in the solids. However, most of the iron, added as Fe(II) aqueous species, remained in solution.

An Immune-CNS Axis Activates Remote Hippocampal Stem Cells Following Spinal Transection Injury.

External stimuli such as injury, learning, or stress influence the production of neurons by neural stem cells (NSCs) in the adult mammalian brain. These external stimuli directly impact stem cell activity by influencing areas directly connected or in close proximity to the neurogenic niches of the adult brain. However, very little is known on how distant injuries affect NSC activation state. In this study, we demonstrate that a thoracic spinal transection injury activates the distally located hippocampal-NSCs. This activation leads to a transient increase production of neurons that functionally integrate to improve animal's performance in hippocampal-related memory tasks. We further show that interferon-CD95 signaling is required to promote injury-mediated activation of remote NSCs. Thus, we identify an immune-CNS axis responsible for injury-mediated activation of remotely located NSCs.

Abrupt emergence of a large pockmark field in the German Bight, southeastern North Sea.

A series of multibeam bathymetry surveys revealed the emergence of a large pockmark field in the southeastern North Sea. Covering an area of around 915 km2, up to 1,200 pockmarks per square kilometer have been identified. The time of emergence can be confined to 3 months in autumn 2015, suggesting a very dynamic genesis. The gas source and the trigger for the simultaneous outbreak remain speculative. Subseafloor structures and high methane concentrations of up to 30 µmol/l in sediment pore water samples suggest a source of shallow biogenic methane from the decomposition of postglacial deposits in a paleo river valley. Storm waves are suggested as the final trigger for the eruption of the gas. Due to the shallow water depths and energetic conditions at the presumed time of eruption, a large fraction of the released gas must have been emitted to the atmosphere. Conservative estimates amount to 5 kt of methane, equivalent to 67% of the annual release from the entire North Sea. These observations most probably describe a reoccurring phenomenon in shallow shelf seas, which may have been overlooked before because of the transient nature of shallow water bedforms and technology limitations of high resolution bathymetric mapping.

[Closure of nasal septum perforations by bridge flaps]. / Cierre de las perforaciones del tabique nasal mediante colgajos «en puente¼

INTRODUCTION: Treating nasal septum perforation is challenging from every point of view for patients who suffer from this condition. This article presents a general overview of this topic and describes an operative technique that very often enables closure of the perforation. MATERIALS AND METHODS: A retrospective and descriptive study was performed on 92 patients who were surgically treated for nasal septum perforation. All patients were treated with the three-layer bridge flap technique for closure of the defect. RESULTS: In 98% of the patients, primary closure of the septum perforation was achieved immediately after removing the silicone sheets. The closure rate 18 months postoperatively was 93.8% (60 of the 64 patients who were examined postoperatively). CONCLUSIONS: Success in closure of the septum perforation was greater than 90% with the 3-layer bridge flap technique. This technique can be performed using an endonasal approach and offers fewer complications in experienced hands. The limitation of this procedure is the height of the perforation.

Long-term results of palisade cartilage tympanoplasty.

OBJECTIVE: Evaluation of morphologic and functional long-term results of palisade cartilage tympanoplasty (PCT) combined with titanium ossicular replacement prostheses. STUDY DESIGN: Retrospective review of tympanoplasties. SETTING: Tertiary referral center. PATIENTS: Twenty-nine patients (12 women and 17 men; mean age, 39 yr; range, 17-72 yr) operated on more than 9 years ago (mean follow up, 9.1 yr) because of cholesteatoma, adhesive otitis, chronic otitis media, subtotal tympanic membrane defects, and tympanic fibrosis requiring tympanoplasty. INTERVENTIONS: Tympanoplasty, applying the PCT. For ossiculoplasty, total or partial titanium ossicular replacement prostheses were used. MAIN OUTCOME MEASURES: Questionnaire on postoperative course, otoscopic findings, and hearing results using a 4-frequency pure-tone average air-bone gap. RESULTS: A recurrent defect was not observed. The graft take rate was 100%. There was one case of prosthesis protrusion which required revision surgery and insertion of a shorter prosthesis. A pure-tone average air-bone gap of 0 to 10 dB was seen preoperatively in 1 ear, 11 to 30 dB in 16 ears, and 31 to 59 dB in 12 ears. Postoperatively, the corresponding numbers were 10, 15, and 4 ears. CONCLUSION: The PCT is a reliable surgical method to manage difficult middle ear pathology on a long-term (>9 yr) basis. It offers satisfactory morphologic and functional results in combination with titanium prosthesis ossiculoplasty.

CD95-ligand on peripheral myeloid cells activates Syk kinase to trigger their recruitment to the inflammatory site.

Injury to the central nervous system initiates an uncontrolled inflammatory response that results in both tissue repair and destruction. Here, we showed that, in rodents and humans, injury to the spinal cord triggered surface expression of CD95 ligand (CD95L, FasL) on peripheral blood myeloid cells. CD95L stimulation of CD95 on these cells activated phosphoinositide 3-kinase (PI3K) and metalloproteinase-9 (MMP-9) via recruitment and activation of Syk kinase, ultimately leading to increased migration. Exclusive CD95L deletion in myeloid cells greatly decreased the number of neutrophils and macrophages infiltrating the injured spinal cord or the inflamed peritoneum after thioglycollate injection. Importantly, deletion of myeloid CD95L, but not of CD95 on neural cells, led to functional recovery of spinal injured animals. Our results indicate that CD95L acts on peripheral myeloid cells to induce tissue damage. Thus, neutralization of CD95L should be considered as a means to create a controlled beneficial inflammatory response.

Biomaterials for craniofacial reconstruction.

Biomaterials for reconstruction of bony defects of the skull comprise of osteosynthetic materials applied after osteotomies or traumatic fractures and materials to fill bony defects which result from malformation, trauma or tumor resections. Other applications concern functional augmentations for dental implants or aesthetic augmentations in the facial region. For ostheosynthesis, mini- and microplates made from titanium alloys provide major advantages concerning biocompatibility, stability and individual fitting to the implant bed. The necessity of removing asymptomatic plates and screws after fracture healing is still a controversial issue. Risks and costs of secondary surgery for removal face a low rate of complications (due to corrosion products) when the material remains in situ. Resorbable osteosynthesis systems have similar mechanical stability and are especially useful in the growing skull. The huge variety of biomaterials for the reconstruction of bony defects makes it difficult to decide which material is adequate for which indication and for which site. The optimal biomaterial that meets every requirement (e.g. biocompatibility, stability, intraoperative fitting, product safety, low costs etc.) does not exist. The different material types are (autogenic) bone and many alloplastics such as metals (mainly titanium), ceramics, plastics and composites. Future developments aim to improve physical and biological properties, especially regarding surface interactions. To date, tissue engineered bone is far from routine clinical application.

Immunohistochemical evidence of BMP-2, -4 and -7 activity in otospongiosis.

CONCLUSION: This study is the first to show that bone morphogenetic proteins (BMP)-2, -4 and -7 play a role in active phase otosclerotic bone remodelling (otospongiosis). OBJECTIVES: The role of BMPs in various tissue growth and repair mechanisms is an ongoing topic in the literature. BMP-2, -4 and -7 are known to be of major importance in bone formation and repair. Their role in otosclerotic bone transformation has not been analysed previously. The main goal of this study was to perform an immunohistological analysis of BMP-2, -4 and -7 in otoclerosis. MATERIALS AND METHODS: Parts of the stapedial footplates, collected during partial stapedectomies in 30 patients with clinical otosclerosis, were analysed for histological otosclerotic lesions after staining haematoxylin and eosin. Immunohistochemical analysis was performed using polyclonal IgG antibodies for BMP-2, -4 and -7, as well as biotinylated secondary antibodies, avidin-biotin-peroxidase complex reaction and alkaline phosphatase staining. RESULTS: In all, 14 specimens contained otosclerosis; 3 of these were otospongiotic, 8 fibrotic, 2 sclerotic and 1 had both sclerotic and fibrotic lesions. Thus in total 14/30 specimens (47%) showed histological otosclerosis. Only the multiple osteoblasts and osteoclasts in those specimens exhibiting an otospongiotic phase showed distinct immunochemical staining for BMP-2, -4 and -7.

Signaling by way of type IB and II bone morphogenetic protein receptors regulates bone formation in otospongiosis.

HYPOTHESIS: The main goal of this study was to perform an immunohistologic analysis of bone morphogenetic protein receptors (BMPR) in otospongiosis. BACKGROUND: BMP-2, -4, and -7 play an essential role in bone formation and repair. They do so as well in otosclerosis. It has been shown that these BMPs are traceable in osteocytes and osteoclasts in the active phase of otosclerosis (otospongiosis). The role of the different BMP receptors in otosclerotic bone transformation has not been previously analyzed. METHODS: The posterior parts of the stapes footplates, collected during partial stapedectomies in 35 patients with clinical otosclerosis, were analyzed for histologic otosclerotic lesions after hematoxylin staining. Immunohistochemical analysis was performed using polyclonal immunoglobulin G antibodies for BMPR-IA, -IB, and -II, as well as biotinylated secondary antibodies, avidin-biotin-peroxidase complex reaction, and alkaline phosphatase staining with nitroblue-tetrazolium-chloride. RESULTS: Seventeen of 35 (49%) specimens contained otosclerosis, but only 5 of these exhibited an otospongiotic phase. The abundant osteoblasts and osteoclasts in these cases showed distinct immunochemical staining for BMP-2, -4, and -7. In two cases, there could also be found an immense positive staining for BMPR-IB and modest staining for BMPR-II, whereas BMPR-1A always remained negative. CONCLUSION: It was demonstrated for the first time that in otospongiosis, the actions of the BMPs are mediated through BMPR-IB and BMPR-II. To determine this role in detail, further investigations, especially for the phosphorylated Smad proteins within the BMP dependent mediator cascade, will be necessary.