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101.
Goodwin TE Eggert MS House SJ Weddell ME Schulte BA Rasmussen LE 《Journal of chemical ecology》2006,32(8):1849-1853
Using automated solid-phase dynamic extraction and gas chromatography-mass spectrometry, our search for urinary chemical signals from ovulatory female African elephants (Loxodonta africana) has revealed the bark beetle aggregation pheromones frontalin, exo-brevicomin, and endo-brevicomin, as well as their precursors and the aphid alarm pheromones (E,E)-alpha-farnesene and (E)-beta-farnesene. Enantiomeric ratios for brevicomins have been determined. Prior discovery of common insect/elephant pheromones in Asian elephants, namely, (Z)-7-dodecenyl acetate and frontalin, suggests that the present findings may yield valuable insights into chemical communication among African elephants. 相似文献
102.
Bashkirov V Schulte R Breskin A Chechik R Schemelinin S Garty G Wroe A Sadrozinski H Grosswendt B 《Radiation protection dosimetry》2006,122(1-4):415-419
An ion-counting nanodosemeter (ND) yielding the distribution of radiation-induced ions in a low-pressure gas within a millimetric, wall-less sensitive volume (SV) was equipped with a silicon microstrip telescope that tracks the primary particles, allowing correlation of nanodosimetric data with particle position relative to the SV. The performance of this tracking ND was tested with a broad 250 MeV proton beam at Loma Linda University Medical Center. The high-resolution tracking capability made it possible to map the ion registration efficiency distribution within the SV, for which only calculated data were available before. It was shown that tracking information combined with nanodosimetric data can map the ionisation pattern of track segments within 150 nm-equivalent long SVs with a longitudinal resolution of approximately 5 tissue-equivalent nanometers. Data acquired in this work were compared with results of Monte Carlo track structure simulations. The good agreement between 'tracking nanodosimetry' data acquired with the new system and simulated data supports the application of ion-counting nanodosimetry in experimental track-structure studies. 相似文献
103.
Evaluation of VOC recovery strategies 总被引:1,自引:0,他引:1
Many manufactured items receive surface coatings for decoration and/or protection against damage. In a number of places along
the production line emissions of (VOC) Volatile Organic Compounds can occur. Because VOC are a major contributor to photochemical
smog, control of VOC emissions is a major concern for the industries' commitment to the environment. Approaches for process
optimisation have a long tradition within chemical and process engineering for the systematic identification of cost- and
resource-efficient production options. The challenge in the context of supply chain management is the optimal recovery and
reuse of materials not only for single substances or energy flows in large chemical installations, but also for smaller production
processes and various mass and energy flows within and between enterprises. Based on a case study from the industrial coating
of bicycle frames, an approach for Multi Objective Pinch Analysis (MOPA) for the evaluation of overall recovery potentials
for energy, water and VOC is presented. Moreover, a metric for resource efficiency is introduced as a measure for the possible
savings potential and for the savings ultimately realised. This integrated approach requires a tight coupling of mass, energy,
economic and environmental assessment methods and demands a highly interdisciplinary approach.
相似文献
O. RentzEmail: |
104.
Christoph Koepple Zizi Zhou Lena Huber Matthias Schulte Kjestine Schmidt Torsten Gloe Ulrich Kneser Volker Jürgen Schmidt Cor de Wit 《International journal of molecular sciences》2021,22(14)
Connexins (Cx) form gap junctions (GJ) and allow for intercellular communication. However, these proteins also modulate gene expression, growth, and cell migration. The downregulation of Cx43 impairs endothelial cell migration and angiogenetic potential. Conversely, endothelial Cx43 expression is upregulated in an in vivo angiogenesis model relying on hemodynamic forces. We studied the effects of Cx43 expression on tube formation and proliferation in HUVECs and examined its dependency on GJ communication. Expectedly, intercellular communication assessed by dye transfer was linked to Cx43 expression levels in HUVECs and was sensitive to a GJ blockade by the Cx43 mimetic peptide Gap27. The proliferation of HUVECs was not affected by Cx43 overexpression using Cx43 cDNA transfection, siRNA-mediated knockdown of Cx43, or the inhibition of GJ compared to the controls (transfection of an empty vector, scrambled siRNA, and the solvent). In contrast, endothelial tube and sprout formation in HUVECs was minimized after Cx43 knockdown and significantly enhanced after Cx43 overexpression. This was not affected by a GJ blockade (Gap27). We conclude that Cx43 expression positively modulates the angiogenic potential of endothelial cells independent of GJ communication. Since proliferation remained unaffected, we suggest that Cx43 protein may modulate endothelial cell migration, thereby supporting angiogenesis. The modulation of Cx43 expression may represent an exploitable principle for angiogenesis induction in clinical therapy. 相似文献
105.
A systematic study of various processes and their impact on intrinsic reliability has been performed on Cu dual damascene interconnects. The most significant improvement for intrinsic reliability is the ‘break-through’ liner. A strong impact on stressmigration (SM) was revealed using a HDP based SiN deposition on top of Cu lines. Early failures in electromigration (EM) studies are present with insufficient cleaning processes. No reliability impact was detected with different plating and slurry chemistries and liner thickness increase. Extrinsic via reliability is assessed with a special test chip comprising 3E9 via/wafer. High ohmic vias are identified before and after thermal stress. As an example, the failure rates in Cu dual damascene levels with relaxed pitch before and after cleaning optimization are discussed. 相似文献
106.
Although it seems that gecko adhesion research is a relatively young branch of science, this recently rediscovered work presents some very old studies with quite remarkable findings. The publication of Dr. F. Weitlaner from 1902 is very impressive, as it covers many recently published topics and – even more impressively – often comes to the same conclusions and provides similar results compared with current publications. Weitlaner published his paper in German which was – at that time – very common in science. This makes it almost impossible for today's international community of bioinspired adhesion researchers to enjoy and appreciate this early gem of scientific work. Thus, we have decided to translate his paper in the hope that it finds the attention it deserves and that it inspires us to stay curious and pursue answers to the questions which have been asked for over a century. 相似文献
107.
Strain steps are applied to elastomers in a pneumatic relaxometer and monitored by small‐angle X‐ray scattering (SAXS). The relaxometer provides a rise time of 13 ms for strain pulses of step height Δε = ±1 in strain. The basic character of the 2D SAXS frames is examined and corresponding invariants Q(t) are analyzed. Three thermoplastic polyurethanes (TPU) of hardness 85 Shore A with different soft segments are studied both unannealed and annealed. The first response of all materials is a fast morphology conversion which finishes within tmc =250 ms. Because it has been untraceable, it is characterized by a settling stroke Q(tmc) ? Q(0). The second response is a slow morphology adjustment process which complies with logarithmic relaxation. It is characterized by a relaxation rate DQ = Q(10 t)/Q(t) ? 1. Comparison indicates that the nanoscopic morphology relaxation processes appear to have little direct relation to the macroscopic stress relaxation curves. The materials differ with respect to hard‐domain morphology stability and morphology recovery. Most unstable is the morphology of the annealed polyether‐based material. It forms nanofibrillary entities when strained. 相似文献
108.
Graham Thiele Dominique Dufour Philippe Vernier Robert O. M. Mwanga Monica L. Parker Elmar Schulte Geldermann Béla Teeken Tesfamicheal Wossen Elisabetta Gotor Enoch Kikulwe Hale Tufan Sophie Sinelle Amani Michel Kouakou Michael Friedmann Vivian Polar Clair Hershey 《International Journal of Food Science & Technology》2021,56(3):1076-1092
This review of the literature on varietal change in sub-Saharan Africa looks in detail at adoption of new varieties of bananas in Uganda, cassava in Nigeria, potato in Kenya, sweetpotato in Uganda and yams in Côte d’Ivoire. The review explored three hypotheses about drivers of varietal change. There was a strong confirmation for the hypothesis that insufficient priority given to consumer-preferred traits by breeding programmes contributes to the limited uptake of modern varieties (MVs) and low varietal turnover. Lack of evidence meant the second hypothesis of insufficient attention to understanding and responding to gender differences in consumer preferences for quality and post-harvest traits was unresolved. The evidence on the third hypothesis about the informal seed system contributing to slow uptake of MVs was mixed. In some cases, the informal system has contributed to rapid uptake of MVs, but often it appears to be a barrier with inconsistent varietal naming a major challenge. 相似文献
109.
We present a scalable solution to render complex scenes from a large amount of viewpoints. While previous approaches rely either on a scene or a view hierarchy to process multiple elements together, we make full use of both, enabling sublinear performance in terms of views and scene complexity. By concurrently traversing the hierarchies, we efficiently find shared information among views to amortize rendering costs. One example application is many‐light global illumination. Our solution accelerates shadow map generation for virtual point lights, whose number can now be raised to over a million while maintaining interactive rates. 相似文献
110.