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The Formation of Calcified Nanospherites during Micropetrosis Represents a Unique Mineralization Mechanism in Aged Human Bone 下载免费PDF全文
Petar Milovanovic Elizabeth A. Zimmermann Annika vom Scheidt Björn Hoffmann George Sarau Timur Yorgan Michaela Schweizer Michael Amling Silke Christiansen Björn Busse 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(3)
Osteocytes—the central regulators of bone remodeling—are enclosed in a network of microcavities (lacunae) and nanocanals (canaliculi) pervading the mineralized bone. In a hitherto obscure process related to aging and disease, local plugs in the lacuno‐canalicular network disrupt cellular communication and impede bone homeostasis. By utilizing a suite of high‐resolution imaging and physics‐based techniques, it is shown here that the local plugs develop by accumulation and fusion of calcified nanospherites in lacunae and canaliculi (micropetrosis). Two distinctive nanospherites phenotypes are found to originate from different osteocytic elements. A substantial deviation in the spherites' composition in comparison to mineralized bone further suggests a mineralization process unlike regular bone mineralization. Clearly, mineralization of osteocyte lacunae qualifies as a strong marker for degrading bone material quality in skeletal aging. The understanding of micropetrosis may guide future therapeutics toward preserving osteocyte viability to maintain mechanical competence and fracture resistance of bone in elderly individuals. 相似文献
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Protecting and preserving clear barrier layers for flexible packaging materials In‐line thermal evaporation of organic topcoat layer 下载免费PDF全文
The end market for transparent flexible barrier films is larger than for metallized films. Presently, the market is still dominated by polymeric barrier layers but the used chemicals may be harmful for the environment. An alternative would be transparent thin layers deposited by vacuum deposition techniques using reactive processes. Ceramic materials like silicon oxide or aluminum oxide are used having a film thickness of just ~10 nm, a coating uniformity of +/?5% across and along the film at a barrier performance below 2.0 sccm/m2d for oxygen transmission rate (OTR) and below 1.0 g/m2d for water vapor transmission rate (WVTR) on PET substrates. In this paper, details will be provided about the deposition processes for these barrier layers using thermal evaporation, plasma‐assisted thermal evaporation as well as deposition by electron beam evaporation. An important factor for these high barrier transparent coatings is also to withstand the downstream processes in the whole packaging stream like slitting, lamination, printing etc. One solution is to protect the barrier layers by a Topcoat. For example, off‐line deposition of lacquers is used in field but the market penetration is low due to high process and material costs. An in‐situ Topcoat deposition is a smart solution to overcome this issue saving time and costs. Such an approach will be also described in the presentation and the impact on the performance of the final package will be discussed. 相似文献
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Graph constraints were introduced in the area of graph transformation, in connection with the notion of (negative) application conditions, as a form to limit the applicability of transformation rules. However, we believe that graph constraints may also play a significant role in the area of visual software modelling or in the specification and verification of semi-structured documents or websites (i.e. HTML or XML sets of documents). In this sense, after some discussion on these application areas, we concentrate on the problem of how to prove the consistency of specifications based on this kind of constraints. In particular, we present proof rules for two classes of graph constraints and show that our proof rules are sound and (refutationally) complete for each class. In addition, we study clause subsumption in this context as a form to speed up refutation. 相似文献
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Dehen CJ Everly RM Plocinik RM Hedderich HG Simpson GJ 《The Review of scientific instruments》2007,78(1):013106
A new instrument was constructed to perform discrete retardance nonlinear optical ellipsometry (DR-NOE). The focus of the design was to perform second harmonic generation NOE while maximizing sample and application flexibility and minimizing data acquisition time. The discrete retardance configuration results in relatively simple computational algorithms for performing nonlinear optical ellipsometric analysis. NOE analysis of a disperse red 19 monolayer yielded results that were consistent with previously reported values for the same surface system, but with significantly reduced acquisition times. 相似文献
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P Kahane L Tassi S Francione D Hoffmann G Lo Russo C Munari 《Canadian Metallurgical Quarterly》1993,23(4):305-326
In patients with severe drug-resistant partial epilepsy, undergoing Stereo-EEG investigations, spatial definition of the "epileptogenic area" is mainly based on spontaneous seizures recordings, but also on seizures induced by intracerebral electrical stimulation (ES). Only "trains" ES (TES, 50 pps) are currently used with this aim; "shocks" ES (SES, 1 pps) are principally applied to localize motor pathways. We have shown, during a prospective study concerning 10 temporal lobe epileptic patients, that SES could frequently induce seizures, especially when stimulation is applied in the anterior part of the Ammon's horn. Even if its efficacy seems lower than by TES, this kind of stimulation, in the majority of the cases, does reproduce isolated ictal subjective symptomatology, allowing the visualization of the progressive organisation of ictal electrical discharges, and avoids "unexpected" ("false positive"?) clinical responses. 相似文献
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Walter Feldheim Ernst Hartmut Reimerdes und Gernot-Rainer Storm 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1977,165(4):204-206
Zusammenfassung Zur quantitativen Bestimmung von Coffein in biologischem Material wird ein kombiniertes Verfahren aus Dünnschichtchromatographie und Densitometrie beschrieben. Das Verfahren läßt Bestimmungen im Nanogramm-Bereich zu. Das Probenvolumen liegt unter 100 l.Die Proben — Capillarblut — werden zunächst mit dem gleichen Volumen Chloroform extrahiert. Anschließend wird das Coffein mittels Dünnschichtchromatographie von Begleitstoffen und störenden Substanzen abgetrennt. Es werden Kieselgel-60-Fertigplatten und Chlorofom/Aceton (9 + 1; v/v) als Fließmittel verwendet, dabei beträgt die Laufzeit 30 min.Die quantitative densitometrische Auswertung erfolgt durch Remissionsmessung bei 273 nm. Im Bereich von 10–60 ng Coffein/Fleck verläuft die Eichkurve linear. 1 mg/I Coffein kann noch sicher quantitativ erfaßt werden. Die Nachweisgrenze liegt bei 0,1 mg/1.
A quantitative micromethod for the caffeine determination
Summary A combined procedure with thin-layer-chromatography and densitometry is described for the quantitative estimation of caffeine in biological material. This method ist applicable in the nanogram range. Test samples of less than 100 l may be used. The samples (capillary-blood) are extracted with the same volume of chloroform. Caffeine is separated from interfering compounds by thin-layer-chromatography. Commercial silica-60-plates with chloroform/acetone (9 + 1; v/v) as solvent are used. The running time is about 30 min. The quantitative densitometric determinations are performed in the remission mode at 273 nm. In the range from 10 to 60 ng/spot the calibration curve is linear. Accurate quantitative data will be obtained even at concentrations of 1 mg/1 caffeine. The detection limit is at about 0.1 mg/1.相似文献
40.
F Markwardt HP Kl?cking K Sedlarik J Perlewitz J Drawert J Hoffmann 《Canadian Metallurgical Quarterly》1976,35(2):193-203
The purpose of this investigation was to explore the feasibility of enhancing the electrochemical stability of dental amalgam restorations by a process of "selective interfacial amalgamation." If dental amalgam restorations can be selectively alloyed at the tooth-amalgam interface, to a minor thickness as compared with the dimensions of the bulk amalgam, so as to present a more electrochemically stable phase than psi2 to the oral environment, corrosion will be reduced and desirable qualities of existing amalgams can be utilized. It was found that selective interfacial amalgamation was indeed possible and that it could be readily accomplished using a silver suspension as a cavity liner. By then placing a conventional silver-tin amalgam according to ordinary dental techniques, mercury expressed during hand condensing reacted with the silver in the liner resulting in the formation of an integral amalgam restoration with the more noble psi1 phase adjacent to tooth structure. In vitro corrosion tests of samples so prepared exhibited corrosion resistance far superior to unlined control samples. 相似文献