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171.
The early Pleistocene deciduous hominid molar FS‐72 from the Sangiran dome of java,Indonesia: A taxonomic reappraisal based on its comparative endostructural characterization 下载免费PDF全文
172.
Karl Kreij Carl-Fredrik Mandenius João J. Clemente António Eduardo Cunha Sandra M. S. Monteiro Manuel J. T. Carrondo Friedemann Hesse Maria Milagros Bassani de los Molinas Roland Wagner Otto-Wilhelm Merten Cécile Gény- Fiamma Wolfgang Leger Herbert Wiesinger-Mayr Dethard Müller Hermann Katinger Per Mårtensson Thomas Bachinger Jan Mitrovics 《Cytotechnology》2005,48(1-3):41-58
An electronic nose (EN) device was used to detect microbial and viral contaminations in a variety of animal cell culture systems.
The emission of volatile components from the cultures accumulated in the bioreactor headspace, was sampled and subsequently
analysed by the EN device. The EN, which was equipped with an array of 17 chemical gas sensors of varying selectivity towards
the sampled volatile molecules, generated response patterns of up to 85 computed signals. Each 15 or 20 min a new gas sample
was taken generating a new response pattern. A software evaluation tool visualised the data mainly by using principal component
analysis. The EN was first used to detect microbial contaminations in a Chinese hamster ovary (CHO) cell line producing a
recombinant human macrophage colony stimulating factor (rhM-CSF). The CHO cell culture was contaminated by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida utilis which all were detected. The response patterns from the CHO cell culture were compared with monoculture references of the
microorganisms. Second, contaminations were studied in an Sf-9 insect cell culture producing another recombinant protein (VP2
protein). Contaminants were detected from E. coli, a filamentous fungus and a baculovirus. Third, contamination of a human cell line, HEK-293, infected with E. coli exhibited comparable results. Fourth, bacterial contaminations could also be detected in cultures of a MLV vector producer
cell line. Based on the overall experiences in this study it is concluded that the EN method has in a number of cases the
potential to be developed into a useful on-line contamination alarm in order to support safety and economical operation for
industrial cultivation. 相似文献
173.
174.
Cannibalism in cephalopods 总被引:1,自引:0,他引:1
Cannibalism refers to the action of consuming a member of the same species and is common in many taxa. This paper reviews
the available literature on cannibalism in cephalopods. All species of the class Cephalopoda are predators and cannibalism
is common in most species whose diet has been studied. Cannibalism in cephalopods is density-dependent due to their aggressive
predatory and in case of the octopuses territorial nature. It also depends upon local and temporal food availability and of
the reproductive season. Cannibalistic behaviour is positively related to the size of both cannibal and victim. It can affect
population dynamics of cephalopods in periods of low food availability and/or high population abundance. Cephalopods are generally
restricted in their ability to store energy. It is thus assumed that cannibalism is part of a population energy storage strategy
enabling cephalopod populations to react to favourable and adverse environmental conditions by increasing and reducing their
number. Finally, we propose five orientation points for future research on cannibalism in cephalopods. 相似文献
175.
Memory traces for words are frequently conceptualized neurobiologically as networks of neurons interconnected via reciprocal links developed through associative learning in the process of language acquisition. Neurophysiological reflection of activation of such memory traces has been reported using the mismatch negativity brain potential (MMN), which demonstrates an enhanced response to meaningful words over meaningless items. This enhancement is believed to be generated by the activation of strongly intraconnected long-term memory circuits for words that can be automatically triggered by spoken linguistic input and that are absent for unfamiliar phonological stimuli. This conceptual framework critically predicts different amounts of activation depending on the strength of the word's lexical representation in the brain. The frequent use of words should lead to more strongly connected representations, whereas less frequent items would be associated with more weakly linked circuits. A word with higher frequency of occurrence in the subject's language should therefore lead to a more pronounced lexical MMN response than its low-frequency counterpart. We tested this prediction by comparing the event-related potentials elicited by low- and high-frequency words in a passive oddball paradigm; physical stimulus contrasts were kept identical. We found that, consistent with our prediction, presenting the high-frequency stimulus led to a significantly more pronounced MMN response relative to the low-frequency one, a finding that is highly similar to previously reported MMN enhancement to words over meaningless pseudowords. Furthermore, activation elicited by the higher-frequency word peaked earlier relative to low-frequency one, suggesting more rapid access to frequently used lexical entries. These results lend further support to the above view on word memory traces as strongly connected assemblies of neurons. The speed and magnitude of their activation appears to be linked to the strength of internal connections in a memory circuit, which is in turn determined by the everyday use of language elements. 相似文献
176.
177.
Claudia Schiffczyk Christina Jonas Constanze Lahmeyer Friedemann Müller Matthias W Riepe 《BMC neurology》2011,11(1):118
Background
Substituted judgment asks the proxy to decide what the patient would have decided, had he or she been competent. It is unclear whether substituted judgment of the patient's quality of life can serve as a surrogate measure in patients with dementia. 相似文献178.
Elke Jeschke Thomas Ostermann Horst C Vollmar Manuela Tabali Friedemann Schad Harald Matthes 《BMC neurology》2011,11(1):99
Background
Dementia is a major and increasing health problem worldwide. This study aims to investigate dementia treatment strategies among physicians specialised in complementary and alternative medicine (CAM) by analysing prescribing patterns and comparing them to current treatment guidelines in Germany. 相似文献179.