High resolution measurement of FGM thin films using picosecond ultrasonics

AbstractFunctionally Graded Materials (FGMs) are materials with elastic properties λ, μ and density ρ depending on spatial coordinates. When between two homogeneous materials the transition layer thickness is of the same order of magnitude as the mechanical wave length, the wave scattering behavior at the interface becomes frequency dependent. The effect is of growing importance for micro- and nanostructures since the relative size of the interface layers is generally larger than in macroscopic structures. In this work a linear material grading is achieved with physical vapor deposition by magnetron sputtering. The used materials are aluminum (Al) and tantalum (Ta) due to their strong variation in acoustic impedance (bulk force reflection coefficient 0.6) and their good intermixing properties. In the sample investigated here the material transition layer thickness amounts to 60nm. With Rutherford Backscattering Spectroscopy (RBS) measurements and electron microscopy (SEM/TEM) the material properties of the sample are characterized. Mechanical waves in the specimen are excited and detected using a pump probe laser acoustic setup. The frequency dependent wave propagation in FGM is demonstrated by investigating the spectral response in theory and experiments. The entire experimental setup is modeled using a finite difference algorithm for better interpretation of the measurements. The frequency dependent wave propagation in FGM is analyzed to characterize the interface and finds applications in high frequency filters, semiconductor manufacturing or thermal barrier layers

Successive ionic layer deposition: possibilities for gas sensor applications

In this paper we discuss results of research related to design of successive ionic layer deposition (SILD) technology for both preparing porous nano-structured SnO2 films, and surface modification of SnO2 films deposited by spray pyrolysis. This new method of metal oxide deposition has exited high interest, because of this method simplicity, cheapness, and ability to deposit thin nano-structured films on rough surfaces. Method of successive ionic layer deposition (SILD) consists essentially of repeated successive treatments of the conductive or dielectric substrates by solutions of various salts, which form on the substrate surface poorly soluble compounds. It was shown that SILD technology is effective method for above mentioned purposes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49002/2/jpconf5_15_008.pd

Mutant SF3B1 promotes malignancy in PDAC

The splicing factor SF3B1 is recurrently mutated in various tumors, including pancreatic ductal adenocarcinoma (PDAC). The impact of the hotspot mutation SF3B1$^{K700E}$ on the PDAC pathogenesis, however, remains elusive. Here, we demonstrate that Sf3b1$^{K700E}$ alone is insufficient to induce malignant transformation of the murine pancreas, but that it increases aggressiveness of PDAC if it co-occurs with mutated KRAS and p53. We further show that Sf3b1$^{K700E}$ already plays a role during early stages of pancreatic tumor progression and reduces the expression of TGF-β1-responsive epithelial-mesenchymal transition (EMT) genes. Moreover, we found that SF3B1$^{K700E}$ confers resistance to TGF-β1-induced cell death in pancreatic organoids and cell lines, partly mediated through aberrant splicing of Map3k7. Overall, our findings demonstrate that SF3B1$^{K700E}$ acts as an oncogenic driver in PDAC, and suggest that it promotes the progression of early stage tumors by impeding the cellular response to tumor suppressive effects of TGF-β

The Symbiotic Neutron Star Binary GX 1+4/V2116 Ophiuchi

We present multiwavelength observations of this S-type symbiotic LMXB which consists of a 2-min X-ray pulsar accreting from an M6 III giant. This is the only symbiotic system definitely known to contain a neutron star. The steady interstellar extinction toward the binary (Av=5) contrasts the variable N_H inferred from X-ray measurements, most likely evidence for a stellar wind. The mass donor is probably near the tip of the first-ascent red giant branch, in which case the system is 3-6 kpc distant and has an X-ray luminosity of 10^37 erg/s. It is also possible, though less likely, that the donor star is just beginning its ascent of the asymptotic giant branch, in which case the system is 12-15 kpc distant and has an X-ray luminosity of 10^38 erg/s. However, our measured Av argues against such a large distance. We show that the dense (10^9 cm^-3) emission-line nebula enshrouding the binary is powered by UV radiation from an accretion disk. The emission-line spectrum constrains the temperature and inner radius of the disk (and thus the pulsar's magnetic field strength), and we discuss this in the context of the accretion torque reversals observed in the pulsar. We also show that the binary period must be >100 d and is most likely >260 d, making GX 1+4 the only known LMXB with Porb>10 d. If the mass donor fills its Roche lobe, the mass transfer must be highly super-Eddington, requiring much mass loss from the binary. We discuss the alternative that the disk forms from the slow, dense stellar wind expected from the red giant.Comment: 46 pages including 7 PS figures. Accepted for publication in Ap

CRISPR/Cas9 DNA cleavage at SNP-derived PAM enables both in vitro and in vivo KRT12 mutation-specific targeting

CRISPR/Cas9-based therapeutics hold the possibility for permanent treatment of genetic disease. The potency and specificity of this system has been used to target dominantly inherited conditions caused by heterozygous missense mutations through inclusion of the mutated base in the short-guide RNA (sgRNA) sequence. This research evaluates a novel approach for targeting heterozygous single-nucleotide polymorphisms (SNPs) using CRISPR/Cas9. We determined that a mutation within KRT12, which causes Meesmann's epithelial corneal dystrophy (MECD), leads to the occurrence of a novel protospacer adjacent motif (PAM). We designed an sgRNA complementary to the sequence adjacent to this SNP-derived PAM and evaluated its potency and allele specificity both in vitro and in vivo. This sgRNA was found to be highly effective at reducing the expression of mutant KRT12 mRNA and protein in vitro. To assess its activity in vivo we injected a combined Cas9/sgRNA expression construct into the corneal stroma of a humanized MECD mouse model. Sequence analysis of corneal genomic DNA revealed non-homologous end-joining repair resulting in frame-shifting deletions within the mutant KRT12 allele. This study is the first to demonstrate in vivo gene editing of a heterozygous disease-causing SNP that results in a novel PAM, further highlighting the potential for CRISPR/Cas9-based therapeutics

Coordination of Cell Differentiation and Migration in Mathematical Models of Caudal Embryonic Axis Extension

Vertebrate embryos display a predominant head-to-tail body axis whose formation is associated with the progressive development of post-cranial structures from a pool of caudal undifferentiated cells. This involves the maintenance of active FGF signaling in this caudal region as a consequence of the restricted production of the secreted factor FGF8. FGF8 is transcribed specifically in the caudal precursor region and is down-regulated as cells differentiate and the embryo extends caudally. We are interested in understanding the progressive down-regulation of FGF8 and its coordination with the caudal movement of cells which is also known to be FGF-signaling dependent. Our study is performed using mathematical modeling and computer simulations. We use an individual-based hybrid model as well as a caricature continuous model for the simulation of experimental observations (ours and those known from the literature) in order to examine possible mechanisms that drive differentiation and cell movement during the axis elongation. Using these models we have identified a possible gene regulatory network involving self-repression of a caudal morphogen coupled to directional domain movement that may account for progressive down-regulation of FGF8 and conservation of the FGF8 domain of expression. Furthermore, we have shown that chemotaxis driven by molecules, such as FGF8 secreted in the stem zone, could underlie the migration of the caudal precursor zone and, therefore, embryonic axis extension. These mechanisms may also be at play in other developmental processes displaying a similar mode of axis extension coupled to cell differentiation

Allele specific repair of splicing mutations in cystic fibrosis through AsCas12a genome editing.

Funder: Fondazione Fibrosi Cistica - FFC#1/2017Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the CFTR gene. The 3272-26A>G and 3849+10kbC>T CFTR mutations alter the correct splicing of the CFTR gene, generating new acceptor and donor splice sites respectively. Here we develop a genome editing approach to permanently correct these genetic defects, using a single crRNA and the Acidaminococcus sp. BV3L6, AsCas12a. This genetic repair strategy is highly precise, showing very strong discrimination between the wild-type and mutant sequence and a complete absence of detectable off-targets. The efficacy of this gene correction strategy is verified in intestinal organoids and airway epithelial cells derived from CF patients carrying the 3272-26A>G or 3849+10kbC>T mutations, showing efficient repair and complete functional recovery of the CFTR channel. These results demonstrate that allele-specific genome editing with AsCas12a can correct aberrant CFTR splicing mutations, paving the way for a permanent splicing correction in genetic diseases

TPR Investigation of bimetallic Ru-Cu samples supported on SiO 2 , Al 2 O 3 and MgO

Bimetallic Ru-Cu samples supported on SiO 2 , Al 2 O 3 and MgO were studied by the temperature-programmed reduction (TPR) technique. Experiments were carried out both on unreduced impregnated salts and after oxidation of already reduced samples. The TPR profiles reveal a simultaneous reduction of ruthenium and copper precursors, even though the Ru and Cu in the monometallic catalysts exhibit reduction peaks which differ by up to 150 °C. It is suggested that the two metal salts interact during the stages of preparation and drying, and after reduction form bimetallic aggregates which are not stable and tend to separate. The stability of the bimetallic particles was found to be strongly dependent on the support used, being higher on SiO 2 than on Al 2 O 3 and MgO. It is suggested that the chemical nature of the support determines the different degree of interaction and/or agglomeration of the bimetallic particles. Auf SiO 2 , Al 2 O 3 und MgO aufgebrachte bimetallische Ru-Cu-Proben wurden mittels temperaturprogrammierter Reduktion (TPR) untersucht. Experimente wurden sowohl mit unreduzierten, durch Impregnation aufgebrachten Salzen als auch mit nach vorangegangener Reduktion reoxydierten Proben ausgeführt. Die TPR-Profile lassen eine gleichzeitige Reduktion der Ruthenium- und Kupfervorstufen erkennen, obwohl Ru und Cu in monometallischen Katalysatoren Reduktionspeaks zeigen, die um bis zu 150 °C voneinander entfernt liegen. Es wird angenommen, daß die zwei Metallsalze während des Darstellungs- und Trocknungsstadiums miteinander in Wechselwirkung treten und nach der Reduktion nicht stabile, zum Zerfall tendierende bimetallische Aggregate bilden. Die Stabilität der bimetallischen Partikel ist stark vom Träger abhängig, sie ist an SiO 2 höher als an Al 2 O 3 und MgO. Es wird angenommen, daß die chemische Natur des Trägers den Grad der Wechselwirkung und/oder Agglomeration der bimetallischen Partikel bestimmt. Методом температурн о-программного восстановления (ТПВ) и зучены биметаллические обр азцы рутений — медь на подложках из двуокиси кремния, о киси алюминия и окиси магния. Экспер именты были проведен ы как с невосстановленными пропитанными солями, так и с вновь ок исленными ранее восстановленными об разцами. Профили крив ых показывают одноврем енное восстановлени е рутения и меди, тогда как в случа е монометаллов пики восстановления рутения и меди отлича ются на 150 °C, Это свидетельствует о том, что соли обоих металлов взаим одействуют между соб ой на стадии получения и высушива ния, а после восстановления обра зуют биметаллически е агрегаты, которые неустойчивы и имеют тенденцию к разделению. Установ лено, что стабильност ь биметаллических час тиц сильно зависит от характера подложки, я вляясь более высокой на двуокиси кремния по сравнению с тем, что на окиси алюминия и окис и магния. Предположен о, что химическая природа п одложки определяет различную степень вз аимодействия или агл омерации биметаллических час тиц.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43142/1/10973_2005_Article_BF01912699.pd

Loss of the BMP Antagonist, SMOC-1, Causes Ophthalmo-Acromelic (Waardenburg Anophthalmia) Syndrome in Humans and Mice

Ophthalmo-acromelic syndrome (OAS), also known as Waardenburg Anophthalmia syndrome, is defined by the combination of eye malformations, most commonly bilateral anophthalmia, with post-axial oligosyndactyly. Homozygosity mapping and subsequent targeted mutation analysis of a locus on 14q24.2 identified homozygous mutations in SMOC1 (SPARC-related modular calcium binding 1) in eight unrelated families. Four of these mutations are nonsense, two frame-shift, and two missense. The missense mutations are both in the second Thyroglobulin Type-1 (Tg1) domain of the protein. The orthologous gene in the mouse, Smoc1, shows site- and stage-specific expression during eye, limb, craniofacial, and somite development. We also report a targeted pre-conditional gene-trap mutation of Smoc1 (Smoc1tm1a) that reduces mRNA to ∼10% of wild-type levels. This gene-trap results in highly penetrant hindlimb post-axial oligosyndactyly in homozygous mutant animals (Smoc1tm1a/tm1a). Eye malformations, most commonly coloboma, and cleft palate occur in a significant proportion of Smoc1tm1a/tm1a embryos and pups. Thus partial loss of Smoc-1 results in a convincing phenocopy of the human disease. SMOC-1 is one of the two mammalian paralogs of Drosophila Pentagone, an inhibitor of decapentaplegic. The orthologous gene in Xenopus laevis, Smoc-1, also functions as a Bone Morphogenic Protein (BMP) antagonist in early embryogenesis. Loss of BMP antagonism during mammalian development provides a plausible explanation for both the limb and eye phenotype in humans and mice