109 research outputs found
The Residue of Flight: Investigations Into the Life of Matter
This thesis is a journey that unfolds alongside the transformations of a river during springtime. Moods and movements captured by Ted Hughes in his poem Stump Pool in April inspire a series of explorations that set out to express the affective vectors of the riverâs becoming through sculpture and architecture. The thesis is a manifestation of this search.
Arranged as a narrative in five chapters, each offers an account of the emergence of the five works. The first three are a sculptural response to each stanza of the poem: Prometheus manifests the riverâs phase-shift from ice to water, Sky Burial from water to steam and Icarus the passage of steam rising towards the sun. Prometheusâ torment, the tearing dispersal of the body during a funerary ritual and the ecstatic flight of Icarus are caught through three material and fire based experiments. Chapter four reflects on these works while investigating the conception and construction of the Bruder Klaus Chapel by the renowned Swiss architect Peter Zumthor. The fifth chapter moves the exploration from sculpture to architectural design deploying the lessons learned from the previous works. Forces of descent rather than ascent now inform the creation of a torrential void, A Loverâs Enclosure.
The trajectory in each work and through the series is guided by what feels right, by the unpredictability of the material imagination, working by hand, and by forming and re-forming reoccurring themes as they reverberate and transform in a continuum of affective transformations
HIP to be Square: Simplifying Nitridophosphate Synthesis in a Hot Isostatic Press
(Oxo)Nitridophosphates have recently been identified as a promising compound class for application in the field of solidâstate lighting. Especially, the latest mediumâpressure syntheses under ammonothermal conditions draw attention of the semiconductor and lighting industry on nitridophosphates. In this contribution, we introduce hot isostatic presses as a new type of mediumâpressure synthetic tool, further simplifying nitridophosphate synthesis. In a second step, phosphorus nitride was replaced as starting material by red phosphorus, enabling the synthesis of Ca2PN3 as model compound, starting only from readily available compounds. Moreover, first luminescence investigations on Eu2+âdoped samples reveal Ca2PN3:Eu2+ as a promising broadâband redâemitter (λem=650â
nm; fwhm=1972â
cmâ1). Besides simple handling, the presented synthetic method offers access to large sample volumes, and the underlying reaction conditions facilitate singleâcrystal growth, required for excellent optical properties
Sr3P3N7: Complementary Approach by Ammonothermal and HighâPressure Syntheses
Nitridophosphates exhibit an intriguing structural diversity with different structural motifs, for example, chains, layers or frameworks. In this contribution the novel nitridophosphate Sr3P3N7 with unprecedented dreier double chains is presented. Crystalline powders were synthesized using the ammonothermal method, while single crystals were obtained by a highâpressure multianvil technique. The crystal structure of Sr3P3N7 was solved and refined from singleâcrystal Xâray diffraction and confirmed by powder Xâray methods. Sr3P3N7 crystallizes in monoclinic space group P 2/c . Energyâdispersive Xâray and Fourierâtransformed infrared spectroscopy were conducted to confirm the chemical composition, as well as the absence of NHx functionality. The optical band gap was estimated to be 4.4â
eV using diffuse reflectance UV/Vis spectroscopy. Upon doping with Eu2+, Sr3P3N7 shows a broad deepâred to infrared emission (λem=681â
nm, fwhmâ3402â
cmâ1) with an internal quantum efficiency of 42â%
Ammonothermal Synthesis of Ba2PO3N â An Oxonitridophosphate with NonâCondensed PO3N Tetrahedra
The orthoâoxonitridophosphate Ba2PO3N was synthesized under ammonobasic conditions (T = 1070 K, p = 120 MPa) in customâbuilt highâtemperature autoclaves, starting from red phosphorus, BaO, NaN3 and KOH. Thus, single crystals of up to several hundred ”m were obtained, which were used for singleâcrystal Xâray diffraction. Ba2PO3N [Pnma (no. 62), a = 7.596(2), b = 5.796(1), c = 10.212(3) Ă
, Z = 4] crystallizes in the ÎČâK2SO4 structure type with nonâcondensed [PO3N]4â ions and is isotypic to its lighter homologues EA2PO3N (EA = Ca, Sr). Powder Xâray diffraction, energy dispersive Xâray and Fourier Transformed Infrared spectroscopy corroborate the crystal structure. The optical band gap was determined by means of diffuse reflectance UV/Vis spectroscopy to be 4.3 eV. Eu2+ doped samples show green luminescence (λem = 534 nm, fwhm = 85 nm/2961 cmâ1) when irradiated with UV light (λexc = 420 nm). However, Ba2PO3N:Eu2+ shows strong thermal quenching, even at room temperature
Time and phenotype-dependent transcriptome analysis in AAV-TGFÎČ1 and Bleomycin-induced lung fibrosis models
We have previously established a novel mouse model of lung fibrosis based on Adeno-associated virus (AAV)-mediated pulmonary overexpression of TGFÎČ1. Here, we provide an in-depth characterization of phenotypic and transcriptomic changes (mRNA and miRNA) in a head-to-head comparison with Bleomycin-induced lung injury over a 4-week disease course. The analyses delineate the temporal state of model-specific and commonly altered pathways, thereby providing detailed insights into the processes underlying disease development. They further guide appropriate model selection as well as interventional study design. Overall, Bleomycin-induced fibrosis resembles a biphasic process of acute inflammation and subsequent transition into fibrosis (with partial resolution), whereas the TGFÎČ1-driven model is characterized by pronounced and persistent fibrosis with concomitant inflammation and an equally complex disease phenotype as observed upon Bleomycin instillation. Finally, based on an integrative approach combining lung function data, mRNA/miRNA profiles, their correlation and miRNA target predictions, we identify putative drug targets and miRNAs to be explored as therapeutic candidates for fibrotic diseases. Taken together, we provide a comprehensive analysis and rich data resource based on RNA-sequencing, along with a strategy for transcriptome-phenotype coupling. The results will be of value for TGFÎČ research, drug discovery and biomarker identification in progressive fibrosing interstitial lung diseases
2-Hydrazonyl-Propandihydrazide - A Versatile Precursor for High-Energy Materials
In this work, 2-hydrazonyl-propandihydrazide (2), a new precursor for energetic materials based on diethyl 2,2-diazidomalonate (1) was investigated. Therefore, its versatility was shown by various secondary reactions, including formation of energetic salts (3-5), the synthesis of a nitrogen-rich bistriazole (10) and a highly instable diazido derivative (6). In addition, a Curtius degradation could be observed in detail. When possible, the compounds were analyzed by low temperature X-ray diffraction. All measurable compounds were analyzed by H-1 and C-13 NMR spectroscopy, elemental analysis, differential thermal analysis (DTA) and regarding their sensitivity towards impact and friction according to BAM standard techniques. All promising compounds were evaluated regarding their energetic behavior using the EXPLO5 code (V6.05) and compared to RDX and CL-20. In addition, compound 2 was investigated towards its aquatic toxicity, using the bioluminescent bacteria vibrio fischeri
Electrochemical development of hydrogen silsesquioxane by applying an electrical potential
We present a new method for developing hydrogen silsesquioxane (HSQ) by using electrical potentials and deionized water. Nested-L test structures with a pitch as small as 9 nm were developed using this electrochemical technique in saline solution without adding hydroxyl ions. Furthermore, we showed that high-resolution structures can be electrochemically developed in deionized water alone. Electrochemical development is controlled by the applied voltage and may overcome several of the limitations discussed for alkaline developers, such as poor hydroxyl anion diffusion and charge repulsion effects in small trenches.National Science Foundation (U.S.)Massachusetts Institute of Technology. Materials Processing CenterMassachusetts Institute of Technology. Center for Materials Science and Engineerin
NitridophosphateâBased UltraâNarrowâBand BlueâEmitters: Luminescence Properties of AEP8N14:Eu2+ (AE=Ca, Sr, Ba)
The nitridophosphates AEP8N14 (AE=Ca, Sr, Ba) were synthesized at 4â5â
GPa and 1050â1150â°C applying a 1000â
t press with multianvil apparatus, following the azide route. The crystal structures of CaP8N14 and SrP8N14 are isotypic. The space group Cmcm was confirmed by powder Xâray diffraction. The structure of BaP8N14 (space group Amm2) was elucidated by a combination of transmission electron microscopy and diffraction of microfocused synchrotron radiation. Phase purity was confirmed by Rietveld refinement. IR spectra are consistent with the structure models and the chemical compositions were confirmed by Xâray spectroscopy. Luminescence properties of Eu2+âdoped samples were investigated upon excitation with UV to blue light. CaP8N14 (λem=470â
nm; fwhm=1380â
cmâ1) and SrP8N14 (λem=440â
nm; fwhm=1350â
cmâ1) can be classified as the first ultraânarrowâband blueâemitting Eu2+âdoped nitridophosphates. BaP8N14 shows a notably broader blue emission (λem=417/457â
nm; fwhm=2075/3550â
cmâ1)
Comparison between phosphine and NHC-modified Pd catalysts in the telomerization of butadiene with methanol â a kinetic study combined with model-based experimental analysis
The authors thank the European Community within its project SYNFLOW (FP7; grant agreement n8 NMP2-LA-2010-246461) for financial support.The telomerization of butadiene with methanol was investigated in the presence of different palladium catalysts modified either with triphenylphosphine (TPP) or 1,3-dimesityl-imidazol-2-ylidene (IMes) ligand. When pure butadiene was used as substrate, a moderate selectivity for the Pd-TPP catalyst toward the desired product 1-methoxy-2,7-octadiene (1-Mode) of around 87 % was obtained, while the IMes carbene ligand almost exclusively formed 1-Mode with 97.5 % selectivity. The selectivity remained unchanged when the pure butadiene feed was replaced by synthetic crack-C4 (sCC4), a technical feed of 45 mol% butadiene and 55 mol% inerts (butenes and butanes). The TPP-modified catalyst showed a lower reaction rate, which was attributed to the expected dilution effect caused by the inerts. Surprisingly, the IMes-modified catalyst showed a higher rate with sCC4 compared to the pure feed. By means of a model-based experimental analysis, kinetic rate equations could be derived. The kinetic modeling supports the assumption that the two catalyst systems follow different kinetic rate equations. For the Pd-TPP catalyst, the reaction kinetics were related to the Jolly mechanism. In contrast, the Jolly mechanism had to be adapted for the Pd-IMes catalyst as the impact of the base seems to differ strongly from that for the Pd-TPP catalyst. The Pd-IMes system was found to be zero order in butadiene at moderate to high butadiene concentrations and first order in base while the nucleophilicity of the base is influenced by the methanol amount resulting in a negative reaction order for methanol.PostprintPeer reviewe
CcpA- and Shm2-pulsed myeloid dendritic cells induce T-cell activation and enhance the neutrophilic oxidative burst response to aspergillus fumigatus
Aspergillus fumigatus causes life-threatening opportunistic infections in immunocompromised patients. As therapeutic outcomes of invasive aspergillosis (IA) are often unsatisfactory, the development of targeted immunotherapy remains an important goal. Linking the innate and adaptive immune system, dendritic cells are pivotal in anti-Aspergillus defense and have generated interest as a potential immunotherapeutic approach in IA. While monocyte-derived dendritic cells (moDCs) require ex vivo differentiation, antigen-pulsed primary myeloid dendritic cells (mDCs) may present a more immediate platform for immunotherapy. To that end, we compared the response patterns and cellular interactions of human primary mDCs and moDCs pulsed with an A. fumigatus lysate and two A. fumigatus proteins (CcpA and Shm2) in a serum-free, GMP-compliant medium. CcpA and Shm2 triggered significant upregulation of maturation markers in mDCs and, to a lesser extent, moDCs. Furthermore, both A. fumigatus proteins elicited the release of an array of key pro-inflammatory cytokines including TNF-α, IL-1ÎČ, IL-6, IL-8, and CCL3 from both DC populations. Compared to moDCs, CcpA- and Shm2-pulsed mDCs exhibited greater expression of MHC class II antigens and stimulated stronger proliferation and IFN-Îł secretion from autologous CD4+ and CD8+ T-cells. Moreover, supernatants of CcpA- and Shm2-pulsed mDCs significantly enhanced the oxidative burst in allogeneic neutrophils co-cultured with A. fumigatus germ tubes. Taken together, our in vitro data suggest that ex vivo CcpA- and Shm2-pulsed primary mDCs have the potential to be developed into an immunotherapeutic approach to tackle IA
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