Technische Hochschule Wildau
  • Wildau, Brandenburg, Germany
Recent publications
Developing quantum key distribution (QKD) has been recently directed toward distance extension and network expansion for real-world secure communications. Considering a recent report on a quantum communication network over 4,600 km, it seems that QKD networks using conventional protocols have been sufficiently studied. However, although the twin-field QKD (TF-QKD) proposed for long-distance QKD has been studied deeply enough to succeed the demonstrations over 428- and 511-km deployed fibers, TF-QKD networks have been verified only for a ring network. In this work, we propose a star topological 2 × N TF-QKD network scheme, where the coherence maintenance issue, being the primary obstacle to implementing TF-QKD, can be minimized by the automatic mode-matching feature of the Sagnac-based plug-and-play architecture. A lower number of active controllers is required for our scheme in comparison with one-way TF-QKD networks. Moreover, our scheme adopts a cost-effective configuration that requires only a single pair of single-photon detectors for the entire network system. We conducted a proof-of-concept experiment over a 50-km fiber successfully, achieving an average secret key rate of 1.31 × 10 −4 bit per pulse (1.52 bit per second) with the finite-size effect.
This study established a dynamic Z-scheme driven heterostructure of ZnO-ZnS (ZnOS) nanoparticles (NPs) by sulfidation of ZnO NPs. The ZnOS composites with different atomic ratios of S/O were analyzed with multiple characterization techniques. The composite materials with a S/O atomic ratio of 1:1 yielded the best photocatalytic results for toxic Cr(VI) removal from water and H2 production from water under UV light. This study examined a dynamic Z-scheme energy transfer behavior at the junction of ZnOS composites for the first time via atomic and electronic structure modeling using density functional theory (DFT) simulations. ZnOS NPs were further immobilized on polyvinylidene fluoride (PVDF) via a non-solvent-induced phase separation method for functional recovery after photocatalysis.
s A novel approach to Fast Pyrolysis Oil (FPO) upgrading with hydrogen from glycerol aqueous phase reforming (APR) was conducted in a biphasic solution. FPO contains both monomer and polymer compounds which rich in oxygen, giving high acidity and low stability. Hydrogen demanding reaction of depolymerization and hydrodeoxygenation (HDO), often called upgrading, is required to improve FPO properties by converting these compounds to hydrocarbon monomers. APR reaction of glycerol where glycerol is reacted with water to produce hydrogen is one of the renewable choices to obtain hydrogen. Prior to upgrading of FPO, catalyst screening and reaction optimization were studied using phenol as a model compound. Upgrading of FPO with in situ glycerol APR was conducted with Pt/C, facilitating hydrogen production (APR) and utilization (hydrogenation), and H-ZSM-5, facilitating dehydration reaction. n-Decane was added to the reaction as a co-solvent to prevent the condensation of the non-polar fragments of FPO which led to coke formation. Upon upgrading the weight average molecular weight (Mw), polydispersity index (PDI), and oxygen to carbon (O/C) ratio of FPO decreased. The highest hydrocarbon yield (7.7% FPO basis or 34.6% lignin basis) was obtained by combining Pt/C and H-ZSM-5 catalysts with n-decane as a co-solvent. Evidence of progressive depolymerization and sequential demethoxylation, hydrogenation, and deoxygenation during upgrading were observed in the products.
Regarding the disposition of metro lines in order to recover from delays, in the literature there can be found two branches of contributions: descriptions of response rules such as expressing (aka skip stop), holding and short-turning together with case studies of their application. And there are fully-automated optimization models that optimize some specified objective function, e.g. minimizing the total train delays. We are not aware of any study that puts its focus specifically on ring lines (aka circle or loop lines). In the absence in particular of essentially immediate time buffers in turnaround activities in the endpoints, the operation of a circle line is particularly challenging, when comparing it with the common bi-directional lines. In this spirit, we are collecting response rules that are applicable especially for circle lines. We sketch their impacts on the passengers’ travel experience and on the resource schedules for the rolling stock and staff, and we provide illustrative drawings. Moreover, we conducted interviews with experts of eleven metro networks that are operating circle lines. We report their answers, which response rules are applied most often. Despite the limited possibilities along circle lines there is a broad repertoire of response action that is taken regularly – somehow surprisingly, one standard general response rule that is often discussed in the literature and in principle applicable to circle lines, too (expressing), is almost never applied in practice.
Huntington's disease (HD) is a neurodegenerative disorder caused by a polyglutamine expansion in the protein huntingtin (HTT) [55]. While the final pathological consequence of HD is the neuronal cell death in the striatum region of the brain, it is still unclear how mutant HTT (mHTT) causes synaptic dysfunctions at the early stage and during the progression of HD. Here, we discovered that the basal activity of focal adhesion kinase (FAK) is severely reduced in a striatal HD cell line, a mouse model of HD, and the human post-mortem brains of HD patients. In addition, we observed with a FRET-based FAK biosensor [59] that neurotransmitter-induced FAK activation is decreased in HD striatal neurons. Total internal reflection fluorescence (TIRF) imaging revealed that the reduced FAK activity causes the impairment of focal adhesion (FA) dynamics, which further leads to the defect in filopodial dynamics causing the abnormally increased number of immature neurites in HD striatal neurons. Therefore, our results suggest that the decreased FAK and FA dynamics in HD impair the proper formation of neurites, which is crucial for normal synaptic functions [52]. We further investigated the molecular mechanism of FAK inhibition in HD and surprisingly discovered that mHTT strongly associates with phosphatidylinositol 4,5-biphosphate, altering its normal distribution at the plasma membrane, which is crucial for FAK activation [14, 60]. Therefore, our results provide a novel molecular mechanism of FAK inhibition in HD along with its pathological mechanism for synaptic dysfunctions during the progression of HD.
Nitrogen-vacancy (NV) centers in diamond have been developed into essential hardware units for a wide range of solid-state-based quantum technology applications. While such applications require the long spin lifetimes of the NV centers, they are often limited due to decoherence. In this study, we theoretically investigate the decoherence of NV-spin ensembles induced by nitrogen impurities (P1 centers), which are one of the most dominant and inevitable magnetic field noise sources in diamond. We combined cluster correlation expansion and density functional theory to compute the Hahn-echo spin-coherence time of the NV centers for a broad range of P1 concentrations. Results indicate a clear linear dependence of T 2 on P1 concentrations on a log scale with a slope of −1.06, which is in excellent agreement with previous experimental results. The interplay between the Jahn–Teller effect and the hyperfine interaction in the P1 center plays a critical role in determining the bath dynamics and the resulting NV decoherence. Our results provide a theoretical upper bound for the NV-spin T 2 over a wide range of P1 densities, serving as a key reference for materials optimization and spin bath characterization to develop highly coherent NV-based devices for quantum information technology.
Synthetic biomaterials are used to overcome the limited quantity of human-derived biomaterials and to impart additional biofunctionality. Although numerous synthetic processes have been developed using various phases and methods, currently commonly used processes have some issues, such as a long process time and difficulties with extensive size control and high-concentration metal ion substitution to achieve additional functionality. Herein, we introduce a rapid synthesis method using a laser-induced hydrothermal process. Based on the thermal interaction between the laser pulses and titanium, which was used as a thermal reservoir, hydroxyapatite particles ranging from nanometer to micrometer scale could be synthesized in seconds. Further, this method enabled selective metal ion substitution into the apatite matrix with a controllable concentration. We calculated the maximum temperature achieved by laser irradiation at the surface of the thermal reservoir based on the validation of three simplification assumptions. Subsequent linear regression analysis showed that laser-induced hydrothermal synthesis follows an Arrhenius chemical reaction. Hydroxyapatite and Mg2+-, Sr2+-, and Zn2+-substituted apatite powders promoted bone cell attachment and proliferation ability due to ion release from the hydroxyapatite and the selective ion-substituted apatite powders, which had a low crystallinity and relatively high solubility. Laser-induced hydrothermal synthesis is expected to become a powerful ceramic material synthesis technology.
Autism spectrum disorder (ASD) is a neurodevelopmental disorder that exhibits neurobehavioral deficits characterized by abnormalities in social interactions, deficits in communication as well as restricted interests, and repetitive behaviors. The basal ganglia is one of the brain regions implicated as dysfunctional in ASD. In particular, the defects in corticostriatal function have been reported to be involved in the pathogenesis of ASD. Surface deformation of the striatum in the brains of patients with ASD and their correlation with behavioral symptoms was reported in magnetic resonance imaging (MRI) studies. We demonstrated that prenatal valproic acid (VPA) exposure induced synaptic and molecular changes and decreased neuronal activity in the striatum. Using RNA sequencing (RNA-Seq), we analyzed transcriptome alterations in striatal tissues from 10-week-old prenatally VPA-exposed BALB/c male mice. Among the upregulated genes, Nurr1 was significantly upregulated in striatal tissues from prenatally VPA-exposed mice. Viral knockdown of Nurr1 by shRNA significantly rescued the reduction in dendritic spine density and the number of mature dendritic spines in the striatum and markedly improved social deficits in prenatally VPA-exposed mice. In addition, treatment with amodiaquine, which is a known ligand for Nurr1, mimicked the social deficits and synaptic abnormalities in saline-exposed mice as observed in prenatally VPA-exposed mice. Furthermore, PatDp+/− mice, a commonly used ASD genetic mouse model, also showed increased levels of Nurr1 in the striatum. Taken together, these results suggest that the increase in Nurr1 expression in the striatum is a mechanism related to the changes in synaptic deficits and behavioral phenotypes of the VPA-induced ASD mouse model.
Biomass pyrolysis oil is a potentially essential renewable energy source that can serve as an alternative to petroleum-based fuels and chemicals. In this study, biomass pyrolysis oil was converted into petroleum-like deoxygenated hydrocarbons via catalytic hydrodeoxygenation using a titania-supported nickel phosphide catalyst. The phosphor precursor was added to several transition metals, including nickel, cobalt, copper, and iron, supported on titania. The formation of isolated nickel phosphide particles, which were active for complete hydrodeoxygenation, was confirmed by the characterization of prepared catalysts. As a model reactant of biomass pyrolysis oil, a mixture of alkyl-methoxyphenol compounds was hydrodeoxygenated to produce completely deoxygenated compounds, generating an 87% yield of cycloalkanes at 300 °C and 4 MPa H2 for a reaction time of 2 h. The hydrodeoxygenation of biomass pyrolysis oil also generated a 37.4% yield of hydrocarbon fuels. The high hydrodeoxygenation activity can be attributed to the synergy between the hydrogenating metals and the acid sites, which can be improved by electron transfer from a slightly cationic nickel to a slightly anionic phosphor. Furthermore, the addition of phosphor improved the formation of highly dispersed nickel particles, increasing the quantity of hydrogen-adsorbing surface metals. The observations in this study indicate that the efficient conversion of lignocellulose-derivatives into chemicals and fuels can be achieved using modified non-precious transition metal catalysts.
The search for new high-performance dielectric materials has attracted considerable research interest. Several mechanisms to achieve high permittivity have been proposed, such as BaTiO3-based perovskites or CaCu3Ti4O12. However, developing high-performance thin films remains a challenge. Here, we propose a new material design route to achieve high permittivity behavior in atomically thin films. We present a concrete example of Dion–Jacobson-type KSr2-xBixNb3O10 and its cation-exchanged form HSr2-xBixNb3O10, which exhibits a stable colossal permittivity and low dielectric loss. In addition, Sr2(1-x)Bi2xNb3O10-δ nanosheets were obtained by chemical exfoliation, with a high dielectric permittivity of over 500—the highest among all known dielectrics in ultrathin films (<20 nm). The Bi substitution of Sr2Nb3O10 led to a two-fold increase in the dielectric permittivity owing to the higher polarizability of Bi ions. Our proposed method provides a strategy for obtaining new high-k nanoscale dielectrics for use in nanoscaled electronics.
Three ruthenium-supported catalyst beads (Ru/Al2O3, Ru/La2O3-Al2O3 and Ru/La2O2CO3-Al2O3) were synthesized and tested for ammonia decomposition. The catalytic activity of the Ru/La2O2CO3-Al2O3 beads was significantly higher than that of the Ru/Al2O3 and Ru/La2O3-Al2O3 beads. This was primarily attributed to the addition of La, which encouraged electron donation from the bead surface to the Ru particles, increasing the rate of N2 desorption. In particular, a higher Ru surface concentration was achieved over the boundary layer of La2O2CO3 compared with La2O3. This is thought to be a result of steric hindrance, with the crystalline surface of La2O2CO3 acting as a structural stabilizer to significantly limit the penetration of Ru particles into the catalyst bead core. SEM-EDS line scanning of transverse sections of the catalyst beads confirmed a higher Ru concentration on the surface of the catalyst beads for Ru/La2O2CO3-Al2O3 compared with Ru/La2O3-Al2O3 and Ru/Al2O3. In fact, the ratio of surface/bulk Ru concentration in Ru/La2O2CO3-Al2O3 was more than twice that of Ru/Al2O3 at equal Ru loadings. The favorable properties of an La2O2CO3 surface-coating can benefit industrial catalyst synthesis, increasing the surface metal concentration compared with traditional La-based Al2O3 beads and pellets.
Aliha is a maize-based traditional fermented beverage prepared and consumed in Ghana, predominantly in the Volta Region and other parts of Ghana. The study sought to characterize the production processes, the nutritional values, and microbial composition of aliha. A total of 126 aliha producers in the Volta, Greater Accra, and Ashanti Regions were sampled using snowballing to identify and to recruit the producers for the study, using a pretested self-administered questionnaire. The physicochemical and microbial composition were carried out using standard methods. Four different production techniques were identified across the production sites. The variations identified during the production existed across the production chain. The main ingredients used for aliha production are corn, caramel, sugar, and water. However, aliha produced by the ‘original’ method (DN2) presented the best nutritional values (proteins, energy, and calcium), followed by backslopping techniques, AG1 (total carbohydrates and ash), and AG2 (fats and oils and phosphorus). Fungi and Enterobacteriaceae dominated the initial fermentation stages (24 h) with low acid values. However, as the fermentation time increased from 24 h to 72 h, the acid contents of the fermenting beverage increased sharply leading to a drastic reduction of fungi and Enterobacteriaceae contents with increasing records of lactic acid bacterial counts. Even though DN2 presented the best nutritional values, it was highly contaminated. Hence, the producers must be encouraged to use backslopping techniques for safety and to shorten the duration of production.
There is a compelling need to develop disease-modifying therapies for Alzheimer’s disease (AD), the most common neuro-degenerative disorder. Together with recent progress in vector development for efficiently targeting the central nervous system, gene therapy has been suggested as a potential therapeutic modality to overcome the limited delivery of conventional types of drugs to and within the damaged brain. In addition, given increasing evidence of the strong link between glia and AD pathophysiology, therapeutic targets have been moving toward those addressing glial cell pathology. Nurr1 and Foxa2 are transcription/epigenetic regulators that have been reported to cooperatively regulate inflammatory and neurotrophic response in glial cells. In this study, we tested the therapeutic potential of Nurr1 and Foxa2 gene delivery to treat AD symptoms and pathologies. A series of functional, histologic, and transcriptome analyses revealed that the combined expression of Nurr1 and Foxa2 substantially ameliorated AD-associated amyloid β and Tau proteinopathy, cell senescence, synaptic loss, and neuro-inflammation in multiple in vitro and in vivo AD models. Intra-cranial delivery of Nurr1 and Foxa2 genes using adeno-associated virus (AAV) serotype 9 improved the memory and cognitive function of AD model mice. The therapeutic benefits of gene delivery were attained mainly by correcting pathologic glial function. These findings collectively indicate that AAV9-mediated Nurr1 and Foxa2 gene transfer could be an effective disease-modifying therapy for AD.
Rheumatologists in Europe and the USA increasingly rely on fluorescence optical imaging (FOI, Xiralite) for the diagnosis of inflammatory diseases. Those include rheumatoid arthritis, psoriatic arthritis, and osteoarthritis, among others. Indocyanine green (ICG)-based FOI allows visualization of impaired microcirculation caused by inflammation in both hands in one examination. Thousands of patients are now documented and most literature focuses on inflammatory arthritides, which affect synovial joints and their related structures, making it a powerful tool in the diagnostic process of early undifferentiated arthritis and rheumatoid arthritis. However, it has become gradually clear that this technique has the potential to go even further than that. FOI allows visualization of other types of tissues. This means that FOI can also support the diagnostic process of vasculopathies, myositis, collagenoses, and other connective tissue diseases. This work summarizes the most prominent imaging features found in FOI examinations of inflammatory diseases, outlines the underlying anatomical structures, and introduces a nomenclature for the features and, thus, supports the idea that this tool is a useful part of the imaging repertoire in rheumatology clinical practice, particularly where other imaging methods are not easily available.
Aluminum alloys are currently used in a wide variety of industries, and strong aluminum alloys are required for the creation of new components. As a result, multiple scientists are experimenting with various compositions of hybrid aluminum metal matrix composites. The purpose of this experiment was to generate hybridization on aluminum alloy 7076 using stir-casting and nano zirconium dioxide and BN reinforcements. Taguchi’s approach was used to optimize the stir-casting process criteria in this investigation. The parameters employed in this investigation were agitation speed, agitation time, and temperature. The chosen constraints are the percentage of reinforcement (0–12%), the agitation speed, the agitation time, and the molten state temperature. We used a wear tester and a Vickers hardness tester to determine the wear and microhardness of the produced stir casting materials. By optimizing wear parameters, the least wear rate is determined.
NRF2 is considered as a master regulator of cellular defense system under stressed conditions such as oxidative stress. In physiological conditions, NRF2 forms a complex with Keap1‐Cul3 in the cytoplasm and undergoes ubiquitination and subsequent degradation. Under stressed conditions, the interaction between NRF2 and Keap1 is perturbed leading to NRF2 stabilization and migration to the nucleus where NRF2 activates genes accounting for antioxidative activities. Thus, small molecules that can disturb the interaction between NRF2 and Keap1 has been considered as promising for a variety of diseases. Herein, we report development of new, potent inhibitors of the interaction between NRF2 and Keap1 by deconvoluting previous inhibitors followed by structural hybridization. The most potent inhibitor identified by our FP assay showed IC50 of 0.6 μM. We believe that our compounds will help to expand structural diversity of NRF2–Keap1 interaction inhibitors contributing to further development of promising candidates for various diseases. New, potent inhibitors of the interaction between NRF2 and Keap1 was designed and synthesized. Structural hybridization of fragments used in previous NRF2 and Keap1 interaction inhibitors was exploited and the most potent compound 17b inhibited the interaction between NRF2 and Keap1 with an IC50 value of 0.6 μM.
It is challenging to develop alloying anodes with ultrafast charging and large energy storage using bulk anode materials, because of the difficulty of carrier‐ion diffusion and fragmentation of the active electrode material. Herein, we report a rational strategy to design bulk Bi anodes for Na‐ion batteries that feature ultrafast charging, long cyclability, and large energy storage without using expensive nanomaterials and surface modifications. We found that bulk Bi particles gradually transform into a porous nanostructure during cycling in a glyme‐based electrolyte, whereas the resultant structure stores Na ions by forming phases with high Na diffusivity. These features allowed the anodes to exhibit unprecedented electrochemical properties; the developed Na–Bi half‐cell 379 mAhg−1 (97% of that measured at 1C) at 7.7 Ag−1 (20C) during 3500 cycles. It also retained 94% and 93% of the capacity measured at 1C even at extremely fast‐charging rates of 80C and 100C, respectively. The structural origins of the measured properties were verified by experiments and first‐principles calculations. The findings of this study not only broaden our understanding of the underlying mechanisms of fast‐charging anodes, but also provide basic guidelines for searching battery anodes that simultaneously exhibit high capacities, fast kinetics, and long cycling stabilities. This article is protected by copyright. All rights reserved
The self-standing nanorod Co2.4Sn0.6O4 is synthesized as a high-performance anode material in search of high capacity and stable anode materials for sodium-ion batteries. The Co2.4Sn0.6O4 nanorod exhibits a high reversible capacity of 576 mAh g⁻¹ at a current density of 80 mA g⁻¹ and shows excellent high-rate capability. The X-ray absorption spectroscopy study reveals the mechanisms of charge storage reaction and improved cycling performance of Co2.4Sn0.6O4. A partially limited conversion reaction of Co– and Sn-oxide during the cycling effectively regulate the irreversible capacity loss over the cycling that is commonly observed from the conversion and alloying reaction-based anode materials. Furthermore, Co2.4Sn0.6O4 also exhibits superior sodium-ion full cell performance when coupled with a NaNi2/3Bi1/3O2 cathode, demonstrating an energy density of 262 Wh kg⁻¹.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
974 members
Jörn Glökler
  • Fachbereich Ingenieur und Naturwissenschaften
Marcus Frohme
  • Molecular Biotechnology
Fred Lisdat
  • Institute of Applied Life Sciences
Information
Address
Hochschulring 1, 15745, Wildau, Brandenburg, Germany
Website
www.th-wildau.de