Observation of Buried Phosphorus Dopants near Clean Si(100)-(2x1) with Scanning Tunneling Microscopy

We have used scanning tunneling microscopy to identify individual phosphorus dopant atoms near the clean silicon (100)-(2x1) reconstructed surface. The charge-induced band bending signature associated with the dopants shows up as an enhancement in both filled and empty states and is consistent with the appearance of n-type dopants on compound semiconductor surfaces and passivated Si(100)-(2x1). We observe dopants at different depths and see a strong dependence of the signature on the magnitude of the sample voltage. Our results suggest that, on this clean surface, the antibonding surface state band acts as an extension of the bulk conduction band into the gap. The positively charged dimer vacancies that have been observed previously appear as depressions in the filled states, as opposed to enhancements, because they disrupt these surface bands.Comment: 4 pages, 3 figures. TeX for OSX from Wierde

Towards real-time cardiovascular magnetic resonance guided transarterial CoreValve implantation: in vivo evaluation in swine

<p>Abstract</p> <p>Background</p> <p>Real-time cardiovascular magnetic resonance (rtCMR) is considered attractive for guiding TAVI. Owing to an unlimited scan plane orientation and an unsurpassed soft-tissue contrast with simultaneous device visualization, rtCMR is presumed to allow safe device navigation and to offer optimal orientation for precise axial positioning. We sought to evaluate the preclinical feasibility of rtCMR-guided transarterial aortic valve implatation (TAVI) using the nitinol-based Medtronic CoreValve bioprosthesis.</p> <p>Methods</p> <p>rtCMR-guided transfemoral (n = 2) and transsubclavian (n = 6) TAVI was performed in 8 swine using the original CoreValve prosthesis and a modified, CMR-compatible delivery catheter without ferromagnetic components.</p> <p>Results</p> <p>rtCMR using TrueFISP sequences provided reliable imaging guidance during TAVI, which was successful in 6 swine. One transfemoral attempt failed due to unsuccessful aortic arch passage and one pericardial tamponade with subsequent death occurred as a result of ventricular perforation by the device tip due to an operating error, this complication being detected without delay by rtCMR. rtCMR allowed for a detailed, simultaneous visualization of the delivery system with the mounted stent-valve and the surrounding anatomy, resulting in improved visualization during navigation through the vasculature, passage of the aortic valve, and during placement and deployment of the stent-valve. Post-interventional success could be confirmed using ECG-triggered time-resolved cine-TrueFISP and flow-sensitive phase-contrast sequences. Intended valve position was confirmed by ex-vivo histology.</p> <p>Conclusions</p> <p>Our study shows that rtCMR-guided TAVI using the commercial CoreValve prosthesis in conjunction with a modified delivery system is feasible in swine, allowing improved procedural guidance including immediate detection of complications and direct functional assessment with reduction of radiation and omission of contrast media.</p

Characterization of Si(100) homoepitaxy grown in the STM at low temperatures

We explore the growth of low-temperature bulk-like Si(100) homoepitaxy with regard to microscopic surface roughness and defects We characterize films grown at different temperatures up to 500K in-situ by means of an effusion cell added to our UHVSTM. The development of novel architectures for future generation computers calls for high-quality homoepitaxial (WOO) grown at low temperature. Even though Si(100) can be grown crystalline up to a limited thickness: the microstructure reveals significant small-scale surface roughness and defects specific to low-temperature growth. Both can he detrimental to fabrication and operation of small-scale electronic devices

Mining the Secretome of C2C12 Muscle Cells: Data Dependent Experimental Approach To Analyze Protein Secretion Using Label-Free Quantification and Peptide Based Analysis

Secretome analysis faces several challenges including detection of low abundant proteins and the discrimination of bona fide secreted proteins from false-positive identifications stemming from cell leakage or serum. Here, we developed a two-step secretomics approach and applied it to the analysis of secreted proteins of C2C12 skeletal muscle cells since the skeletal muscle has been identified as an important endocrine organ secreting myokines as signaling molecules. First, we compared culture supernatants with corresponding cell lysates by mass spectrometry-based proteomics and label-free quantification. We identified 672 protein groups as candidate secreted proteins due to their higher abundance in the secretome. On the basis of Brefeldin A mediated blocking of classical secretory processes, we estimated a sensitivity of >80% for the detection of classical secreted proteins for our experimental approach. In the second step, the peptide level information was integrated with UniProt based protein information employing the newly developed bioinformatics tool “Lysate and Secretome Peptide Feature Plotter” (LSPFP) to detect proteolytic protein processing events that might occur during secretion. Concerning the proof of concept, we identified truncations of the cytoplasmic part of the protein Plexin-B2. Our workflow provides an efficient combination of experimental workflow and data analysis to identify putative secreted and proteolytic processed proteins

Thirty-day clinical outcomes of the Evolut PRO self-expanding transcatheter aortic valve: the international FORWARD PRO study.

peer reviewedAIMS: The Evolut PRO is a new transcatheter heart valve with an outer pericardial wrap intended to reduce paravalvular leak and facilitate tissue ingrowth. We aimed to evaluate the clinical performance and safety of the Evolut PRO valve in standard practice. METHODS AND RESULTS: FORWARD PRO is a prospective, multinational, multicentre observational study. Transcatheter aortic valve implantation with the Evolut PRO valve (23, 26, or 29 mm) was attempted in 629 non-consecutive patients from 39 centres from February 2018 to January 2019. The primary endpoint was the rate of all-cause mortality at 30 days compared to a pre-specified performance goal. An independent clinical events committee adjudicated safety endpoints based on VARC-2 definitions. All echocardiograms were centrally assessed by an independent core laboratory (Mayo Clinic, Rochester, MN, USA). Baseline characteristics included mean age 81.7±6.1 years, 61.8% female, STS score 4.7±3.3%, and 33.6% were frail. All-cause mortality at 30 days was 3.2%, which was lower than the pre-specified performance goal of 5.5% (p=0.004). Greater than mild AR was present in 1.8% of patients at discharge. CONCLUSIONS: The FORWARD PRO study confirmed the safety and efficacy of the Evolut PRO transcatheter aortic valve system with an external pericardial wrap. ClinicalTrials.gov Identifier: NCT0341701

High Area Capacity Lithium-Sulfur Full-cell Battery with Prelitiathed Silicon Nanowire-Carbon Anodes for Long Cycling Stability

We show full Li/S cells with the use of balanced and high capacity electrodes to address high powerelectro-mobile applications. The anode is made of an assembly comprising of silicon nanowires asactive material densely and conformally grown on a 3D carbon mesh as a light-weight current collector,offering extremely high areal capacity for reversible Li storage of up to 9 mAh/cm2. The dense growthis guaranteed by a versatile Au precursor developed for homogenous Au layer deposition on 3Dsubstrates. In contrast to metallic Li, the presented system exhibits superior characteristics as an anodein Li/S batteries such as safe operation, long cycle life and easy handling. These anodes are combinedwith high area density S/C composite cathodes into a Li/S full-cell with an ether- and lithium triflatebasedelectrolyte for high ionic conductivity. The result is a highly cyclable full-cell with an areal capacityof 2.3 mAh/cm2, a cyclability surpassing 450 cycles and capacity retention of 80% after 150 cycles(capacity loss <0.4% per cycle). A detailed physical and electrochemical investigation of the SiNWLi/S full-cell including in-operando synchrotron X-ray diffraction measurements reveals that the lowerdegradation is due to a lower self-reduction of polysulfides after continuous charging/discharging

High Area Capacity Lithium-Sulfur Full-cell Battery with Prelitiathed Silicon Nanowire-Carbon Anodes for Long Cycling Stability

We show full Li/S cells with the use of balanced and high capacity electrodes to address high power electro-mobile applications. The anode is made of an assembly comprising of silicon nanowires as active material densely and conformally grown on a 3D carbon mesh as a light-weight current collector, offering extremely high areal capacity for reversible Li storage of up to 9 mAh/cm(2). The dense growth is guaranteed by a versatile Au precursor developed for homogenous Au layer deposition on 3D substrates. In contrast to metallic Li, the presented system exhibits superior characteristics as an anode in Li/S batteries such as safe operation, long cycle life and easy handling. These anodes are combined with high area density S/C composite cathodes into a Li/S full-cell with an ether- and lithium triflate-based electrolyte for high ionic conductivity. The result is a highly cyclable full-cell with an areal capacity of 2.3 mAh/cm(2), a cyclability surpassing 450 cycles and capacity retention of 80% after 150 cycles (capacity loss <0.4% per cycle). A detailed physical and electrochemical investigation of the SiNW Li/S full-cell including in-operando synchrotron X-ray diffraction measurements reveals that the lower degradation is due to a lower self-reduction of polysulfides after continuous charging/discharging

High Area Capacity Lithium-Sulfur Full-cell Battery with Prelitiathed Silicon Nanowire-Carbon Anodes for Long Cycling Stability

We show full Li/S cells with the use of balanced and high capacity electrodes to address high power electro-mobile applications. The anode is made of an assembly comprising of silicon nanowires as active material densely and conformally grown on a 3D carbon mesh as a light-weight current collector, offering extremely high areal capacity for reversible Li storage of up to 9 mAh/cm(2). The dense growth is guaranteed by a versatile Au precursor developed for homogenous Au layer deposition on 3D substrates. In contrast to metallic Li, the presented system exhibits superior characteristics as an anode in Li/S batteries such as safe operation, long cycle life and easy handling. These anodes are combined with high area density S/C composite cathodes into a Li/S full-cell with an ether- and lithium triflate-based electrolyte for high ionic conductivity. The result is a highly cyclable full-cell with an areal capacity of 2.3 mAh/cm(2), a cyclability surpassing 450 cycles and capacity retention of 80% after 150 cycles (capacity loss <0.4% per cycle). A detailed physical and electrochemical investigation of the SiNW Li/S full-cell including in-operando synchrotron X-ray diffraction measurements reveals that the lower degradation is due to a lower self-reduction of polysulfides after continuous charging/discharging