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Voltage detected single spin dynamics in diamond at ambient conditions
Full text linkDefect centres in crystals like diamond or silicon find a wide application in quantumtechnology, where the detection and control of their quantum states is crucial for theirimplementation as quantum sensors and qubits. The quantum informationis usuallyencoded in the spin state of these defect centres, but they also often possess a chargewhich is typically not utilized. We report here the detection of elementary chargesbound to single nitrogen vacancy NV centres several nanometres belowthe diamondsurface using Kelvin Probe Force Microscopy KPFM under laser illumination. More over, the measured voltage depends on the NV s electron spin state, thus allowing toperform a non optical single spin readout, a technique we refer to as Voltage DetectedMagnetic Resonance VDMR . Our method opens a novel way of coherent spin dy namics detection for quantum sensing applications and could be appliedto other solidstate systems. We believe that this voltage based readout would help to simplify thedesign of devices for quantum technolog
Making the negative positive fluorination of indole as an efficient strategy to improve guanidinium containing gene carriers
Full text linkThe balance between hydrophilic and hydrophobic components plays an important role in polymeric delivery of nucleic acids. Besides using hydrophobic moieties in the polymer design, fluorination is a promising method to increase the hydrophobicity of polymers. To systematically investigate this effect, N 2 1H indol 3 yl ethyl methacrylamide and three fluorinated analogues have been synthesized and copolymerized with 3 guanidinopropyl methacrylamide and 2 hydroxypropyl methacrylamide via an aqueous reversible addition fragmentation chain transfer aRAFT polymerization. A library of eight terpolymers with 5 to 23 mol of an indole analogue and molar mass about 20 kg mol 1 showed comparably strong DNA binding starting at N P 2 and formed polyplexes with hydrodynamic diameters around 100 nm. Additionally, no negative impact on biocompatibility was observed. Heparin release studies showed increased DNA binding strength with higher amounts of hydrophobic moieties, while fluorination exhibited similar effects as increasing the indole content. This was also important for pDNA transfection efficiency, where an optimum for DNA binding strength was unveiled. The rapid release and the excessive binding of DNA were identified as factors that negatively impacted transfection efficiency, both influenced by the amount of indole moieties and fluorination. On the other hand, the right degree of hydrophobicity was able to increase the transfection efficiency of the modified polymer by more than threefold. These findings highlight the role of hydrophobic moieties in nucleic acid delivery and provide valuable insights for future polymer design, suggesting that the strategic incorporation of fluorinated monomers can effectively fine tune DNA interaction
Tailoring cationic poly 2 oxazoline s Minimizing toxicity and immunogenic response for biological applications
No full textThe increasing importance and potential of nanomedicine are underscored by the successful use of mRNA vaccines. The safe transport of genetic material as an active ingredient represents a significant challenge, for which lipids have thus far been primarily used as a non viral alternative. Cationic polymers are capable of binding and transporting their nucleic acid cargo via electrostatic interactions. However, membrane toxicity, immune activation, and limited biocompatibility restrict the application of cationic polymers, particularly for diseases with critical immune statuses. In this study, degradable poly 2 oxazoline analogues dPOx were synthesized via a post polymerization synthesis route starting from the well known cationic poly ethylene imine PEI . The dPOx feature varying fractions of primary amino moieties in their side chains. The polymers were characterized in detail using 1H NMR spectroscopy, size exclusion chromatography, IR spectroscopy, titration of the amino moieties, and analytical ultracentrifugation. They exhibited reduced cytotoxicity towards human monocytes and exceptional hemocompatibility. Simultaneously, the polymers successfully delivered short synthetic single stranded DNA without inducing the release of pro inflammatory cytokines, a critical factor for the future application of polymers in the field of nanomedicin
Simultaneous Passivatio of Surface and Bulk Defects in All Perovskite Tandem Solar Cells Using Bifunctional Lithium Salts
Full text linkAll perovskite tandem solar cells have garnered considerable attention because of their potential to outperform single junction cells. However, charge recombination losses within narrow bandgap NBG perovskite subcells hamper the advancement of this technology. Herein, we introduce a lithium salt, lithium bis trifluoromethanesulfonyl imide LiTFSI , for modifying NBG perovskites. Interestingly, LiTFSI bifunctionally passivates the surface and bulk of NBG by dissociating into Li and TFSI amp; 8722; ions. We found that TFSI amp; 8722; passivates halide vacancies on the perovskite surface, reducing nonradiative recombination, while Li acts as an interstitial n type dopant, mitigating the defects of NBG perovskites and potentially suppressing halide migration. Furthermore, the underlying mechanism of LiTFSI passivation was investigated through the density functional theory calculations. Accordingly, LiTFSI facilitates charge extraction and extends the charge carrier lifetime, resulting in an NBG device with power conversion efficiency PCE of 22.04 certified PCE of 21.42 and an exceptional fill factor of 81.92 . This enables the fabrication of all perovskite tandem solar cells with PCEs of 27.47 and 26.27 for aperture areas of 0.0935 and 1.02 amp; 8201;cm2, respectivel
Imaging magnetic order in a two dimensional iron rich phyllosilicate
Full text linkMagnetic domain formation in two dimensional materials offers insight into the fundamentals of magnetism and serves as a catalyst for the advancement of spintronics. In order to propel these developments, it is crucial to acquire an understanding of the evolution of magnetic ordering at the nanometer scale. In particular, two dimensional magnetic insulators allow for the realization of atomically sharp magnetoresistive tunneling junctions with nonmagnetic electrodes, therefore lifting one of the major constraints for the realization of computing in memory based on magnetoresistive elements. In this study, we visualize magnetic ordering in monolayers of annite, a fully air stable layered magnetic mica. Using a nanometer scale scanning superconducting quantum interference device microscopy, we directly observe domain formation in this representative of two dimensional magnetic phyllosilicate
Homochiral Carboxylate Anchored Truxene Tripods Design, Synthesis, and Monolayer Formation on Ag 111
No full textCharge Extraction Multilayers Enable Positive Intrinsic Negative Perovskite Solar Cells with Carbon Electrodes
Full text linkPerovskite solar cells achieve high power conversion efficiencies but usually rely on vacuum deposited metallic contacts, leading to high material costs for noble metals and stability issues for more reactive metals. Carbon based materials offer a cost effective and potentially more stable alternative. The vast majority of carbon electrode PSCs use the negative intrinsic positive n i p or hole transport layer free architectures. Here, we present a systematic study to assess the compatibility of inverted , p i n configuration PSC contact layers with carbon top electrodes. We identify incompatibilities between common electron transport layers and the carbon electrode deposition process and previously unobserved semiconducting properties in carbon electrodes with unique implications for charge extraction and electronic behavior. To overcome these issues, we introduce a double layer atomic layer deposited tin oxide SnO2 and Poly 2,3 dihydrothieno 1,4 dioxin poly styrenesulfonate PEDOT PSS , yielding up to 16.1 PCE and a retained 94 performance after 500 h of outdoor aging. The study is a crucial step forward for printable, metal electrode free, and evaporation free perovskite PV technologie
Real time insights into microporous thiophene polymer for lithium sulfur batteries via operando X ray imaging
No full textThis study focuses on the Microporous Thiophene Polymer MTP 1 , a porous organic polymer POP synthesized through environmentally friendly methods. After MTP 1 synthesis, sulfur S8 and the resulting compound, MTP 1 S8, is thoroughly characterized. Electrochemical tests show that MTP 1 S8 acts as a robust positive electrode, retaining over 70 of its capacity after 100 cycles. UV vis spectroscopy confirms the compound s ability to absorb and trap lithium polysulfides LiPSs . Operando electrochemical impedance analysis reveals improved sulfur confinement in MTP 1 S8, evidenced by smaller variations in electrolyte resistance over cycling when compared to the Carbon Black Sulfur CB S8 control electrode used as reference throughout the study. In contrast, CB S8 exhibits significant resistance fluctuations, indicating greater polysulfide diffusion into the electrolyte and a stronger shuttle effect. Operando X ray radiography experiments provide insights into the processes of sulfur formation and dissolution, correlating with specific capacity values. A distinct difference is observed in the size and distribution of sulfur particles between the two systems. The CB S8 exhibits fewer but larger sulfur particles, suggesting lower polysulfide retention near the positive electrode. In contrast, MTP 1 S8 displays a higher number of smaller sulfur particles, indicating better polysulfide retention and enhanced nucleation kinetics. Overall, the green synthesis, advanced characterization, and use of in situ and operando techniques emphasize MTP 1 S8 potential as a high performance sulfur host. The findings contribute to lithium sulfur battery development and improve the understanding of degradation pathway
Exploring Necessary Conditions for Generating Coherent Radiation from Microbunching at the Metrology Light Source
No full textSynchrotron radiation has been indispensable for science and industry over the last decades. Advantageous are the high flexibility and accurate calculability of radiation properties wavelength, power, polarization . Additionally, synchrotron light sources offer high brilliance and the ability to generate very short pulses. Short wavelengths, from extreme ultraviolet EUV to X rays, are especially of interest for measurement techniques requiring high spatial and temporal resolution. However, at these short wavelengths, it has been challenging to realize radiation sources of high average power, the demand for which has been rising in both science and industry. Different ideas have been proposed within the accelerator physics community to address this issue. One of them is steady state microbunching SSMB , a scheme to generate high average power coherent radiation from an electron storage ring. SSMB aims primarily at wavelengths in the EUV range, and promises to deliver unprecedented sustained radiation power of kilowatt level. To investigate if a realization of SSMB is feasible, a proof of principle PoP experiment is conducted at the Metrology Light Source electron storage ring in Berlin. The experiment tests the core aspect of SSMB, the modulation of an electron beam by an optical laser and the fine tuning of the storage ring settings so that microbunches can form, achieving its first goal to show that coherent radiation can be generated in this way in 2019. Following up on the initial success, this thesis focuses on systematic investigations of the necessary conditions to enable generation of microbunches in the SSMB PoP experiment, and maintaining them for several revolutions around the storage ring. It aims to verify the theoretical foundations of SSMB and probe areas of longitudinal electron beam dynamics that have not been visited so far. Multiple aspects are in focus, the investigation of each building on and refining the results of the previous one. These include studies on the requirements for the laser modulation creating the microbunch structures; investigations on the stability of the emitted coherent synchrotron radiation, identifying possible sources of the observed fluctuation; an examination of the impact of transverse beam dynamics on the longitudinal microstructures; and an exploration of the influence of non linearity in the phase slippage function that is governing the microbunching process. To enable the examination of the final aspect of nonlinear phase slippage, for the first time a fully rigorous framework of the necessary definitions and relations is introduced, dealing with how to properly employ the concept of phase slippage at variable beam momentum. Gaining full understanding and the ability to control each of these aspects is crucial for the continuing development effort for SSMB. The insights gained during the proof of principle campaign and presented in this work are important foundations for the future realization of SSMB light source
Selectivity and Safety Characterization of a Xanthine Imidazothiazole Lead Structure a Novel Tryptophan Hydroxylase Inhibitor of Peripheral Serotonin Synthesis
No full textSerotonin 5 HT , a crucial neurotransmitter and peripheral mediator, regulates various physiological processes and is synthesized by tryptophan hydroxylase 1 TPH1 , the rate limiting enzyme responsible for its production. 5 HT overproduction is implicated in multiple diseases, making TPH1 a promising therapeutic target. However, selectivity remains a challenge due to the structural similarity of TPH1 with other members of the aromatic amino acid hydroxylase AAAH family, including TPH2, phenylalanine hydroxylase PAH , and tyrosine hydroxylase TH . This study aimed to evaluate the selectivity and inhibitory potential of TPT 004, a novel TPH inhibitor, compared with Telotristat LP778902 and its prodrug LX1606 . We developed high throughput fluorescence assays to evaluate the inhibitory effects of the test compounds on TPH1, TPH2, PAH, and TH enzymes. TPT 004 demonstrated high selectivity for TPHs compared to LP778902 and LX1606. Structural analysis based on a detailed sequence alignment within the AAAH enzyme family, combined with cocrystal structures of TPH1 and TPH2 bound to different generations of inhibitors, enhances our understanding of the molecular basis of inhibitor binding and provides a framework for explaining TPT 004 s selectivity for TPHs. Selectivity profiling against 97 targets confirmed that TPT 004 showed minimal off target interactions, underscoring its specificity. A dose range finding DRF study in rats assessed the in vivo safety profile of TPT 004, showing no adverse effects on survival and body weight at doses up to 400 mg kg day. Hematology parameters remained normal, with only minor liver changes observed. These results highlight TPT 004 s potential as a selective and safe TPH inhibitor, offering a promising therapeutic option for serotonin related disorder