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101.
Summary Microbiological leaching of complex sulfide ore material was evaluated in percolators at 4, 10, and 20°C. The onset of leaching was associated with an increase in redox potential and a decrease in pH. Copper from chalcopyrite was leached at a slow rate at each test temperature compared with the leaching of zinc from sphalerite and nickel from pentlandite. 相似文献
102.
John M. Ratcliffe Lasse Jakobsen Elisabeth K. V. Kalko Annemarie Surlykke 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(5):413-423
The greater sac-winged bat, Saccopteryx bilineata (Emballonuridae), uses two distinct echolocation call sequences: a ‘monotonous’ sequence, where bats emit ~48 kHz calls at
a relatively stable rate, and a frequency-alternating sequence, where bats emit calls at ~45 kHz (low-note call) and ~48 kHz
(high-note call). The frequencies of these low–high-note pairs remain stable within sequences. In Panama, we recorded echolocation
calls from S. bilineata with a multi-microphone array at two sites: one a known roosting site, the other a known foraging site. Our results indicate
that this species (1) only produces monotonous sequences in non-foraging contexts and, at times, directly after emitting a
feeding buzz and (2) produces frequency-alternating sequences when actively foraging. These latter sequences are also characterized
by an unusual, offbeat emission rhythm. We found significant positive relationships between (1) call intensity and call duration
and (2) call intensity and distance from clutter. However, these relationships were weaker than those reported for bats from
other families. We speculate on how call frequency alternation and an offbeat emission rhythm might reflect a novel strategy
for prey detection at the edge of complex habitat in this ancient family of bats. 相似文献
103.
Mikkel Winther Pedersen Bianca De Sanctis Nedda F. Saremi Martin Sikora Emily E. Puckett Zhenquan Gu Katherine L. Moon Joshua D. Kapp Lasse Vinner Zaruhi Vardanyan Ciprian F. Ardelean Joaquin Arroyo-Cabrales James A. Cahill Peter D. Heintzman Grant Zazula Ross D.E. MacPhee Beth Shapiro Richard Durbin Eske Willerslev 《Current biology : CB》2021,31(12):2728-2736.e8
104.
Anne van den Wittenboer Thomas Schmidt Pia Müller Marion B. Ansorge-Schumacher Lasse Greiner Dr. 《Biotechnology journal》2009,4(1):44-50
Biphasic reaction media are extending the scope of technical biocatalysis. Thorough investigation of the factors affecting catalyst performance under these conditions is of key importance for the successful implementation of catalytic processes. Here, we present a reactor setup suitable for comprehensive systematic characterization and optimization of biocatalyzed reactions in biphasic systems with distinct phases. It is distinguished by small volumes allowing reproducible experimentation with minimum amounts of solvent and catalyst. The interfacial area is kept constant and independent stirring of both phases is allowed in order to minimize superimposing effects. Evaporation of low-volatile organic solvents is prevented by use of airtight construction. The broad applicability of this mini-reactor is demonstrated with regard to determination of mass transfer, enzyme productivity, and enzyme stability in both batch and continuous mode. 相似文献
105.
106.
Jann Lasse Gr?nemeyer Claudia Sofía Burbano Thomas Hurek Barbara Reinhold-Hurek 《Plant and Soil》2012,356(1-2):67-82
Root-associated bacteria can have beneficial effects on their host plants. Microbial products can promote and stimulate plant growth or lead to bioprotection against pathogens. This study aimed to isolate putatively beneficial bacteria from traditional cereals grown by subsistence farmers in the Kavango of Namibia. Bacteria were isolated from surface-sterilized roots of Pennisetum glaucum, Sorghum bicolor, and Zea mays, and subjected to phenotypic and phylogenetic analyses. A total of 44 root-associated bacterial strains were isolated. From 33 distinct isolates, 22 belonged to Firmicutes and Actinobacteria, while 11 were Proteobacteria. Eleven novel phylotypes were among the isolates. Features known to contribute to plant growth-promotion and biocontrol were tested in vitro and revealed promising candidates with multiple beneficial characteristics. This is the first report on the characterization of native isolates associated with important agriculture crops in the Kavango region of Namibia. Such isolates have the potential for application as inoculants adapted to poor soils and local crops. Desiccation-tolerant or sporulating Gram-positive bacteria are of particular interest for this region, which is characterized by a long dry season. 相似文献
107.
Rasmussen LE Vanhoutte PM Jensen BL Skøtt O 《American journal of physiology. Heart and circulatory physiology》2006,291(4):H1521-H1528
Experiments were designed to investigate the influence of steady flow and pressure on endothelial function in the rabbit carotid artery. Increases and decreases in isometric force were compared in static rings and perfused (5 or 50 ml/min) segments of the same arteries in the presence and absence of endothelium. The alpha(1)-adrenoceptor agonist phenylephrine and the muscarinic agonist acetylcholine were applied as vasoconstrictor and vasodilator stimuli, respectively. Continuous flow (5 and 50 ml/min) reduced the cGMP content and shifted the concentration-response curve to phenylephrine to the left compared with nonperfused static rings. Removal of the endothelium abolished the differences in cGMP content and the sensitivity to phenylephrine between static rings and perfused segments. No difference in sensitivity to phenylephrine was observed in tissues treated with N(omega)-nitro-l-arginine methyl ester (l-NAME). Acetylcholine-evoked relaxations were increased in perfused segments. l-NAME nearly abolished the acetylcholine-evoked relaxation in static rings, whereas about one-half of the relaxation remained in segments exposed to flow. This remnant relaxation was blocked by inhibition of endothelial small- and intermediate-conductance calcium-activated potassium channels by apamin plus 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34). These experiments demonstrate that continuous flow increases the constriction evoked by alpha(1)-adrenergic activation in the rabbit carotid artery through a reduced influence of basally released endothelial NO and, furthermore, that luminal flow unmasks an ability of the endothelium to release a non-NO, noncyclooxygenase vasodilator, presumably endothelium-derived hyperpolarizing factor. 相似文献
108.
Dodds MG Frederiksen KS Skak K Hansen LT Lundsgaard D Thompson JA Hughes SD 《Cancer immunology, immunotherapy : CII》2009,58(6):843-854
Purpose Recombinant interleukin-21 (rIL-21) is an immune stimulating cytokine recently tested in two Phase 1 trials for immune responsive
cancers. A secondary objective of these trials was to characterize pharmacodynamic responses to rIL-21 in patients. Here,
we report the effects of systemic rIL-21 on serum markers of immune stimulation.
Experimental design Recombinant IL-21 was administered by intravenous bolus injection at dose levels from 1 to 100 μg/kg using two distinct treatment
regimens: thrice weekly (‘3/w’) for 6 weeks; or once daily for five consecutive days followed by nine dose-free days (‘5 + 9’).
In the absence of dose limiting toxicity, additional cycles of dosing were initiated immediately following the nine dose-free
days. An array of 70 different proteins was profiled in subject serum samples from several time points during the course of
the study. Hierarchical clustering analysis was performed on a normalized subset of these data.
Results Systemic administration of rIL-21 affected the serum levels of several cytokines, chemokines, acute-phase proteins and cell
adhesion proteins. The magnitude and duration of response were dose dependent for a subset of these biomarkers. The 5 + 9
dosing regimen generally produced cyclic changes that were of greater magnitude, as compared to a more chronic stimulation
with the 3/w dosing regimen. Despite these differences, rIL-21 effects on many analytes were similar between regimens when
averaged over the time of treatment. Based on similar temporal, between-subject and dose response changes, groups of analytes
were identified that exhibited distinct components of the rIL-21-mediated immune activation. Biomarkers indicative of lymphocyte
activation (increased IL-16, decreased RANTES), acute phase response (increased CRP, ferritin), myeloid activation (increased
MDC, MIP-1 alpha), and leukocyte chemotaxis/trafficking (increased sCAMs, MCP-1) were strongly modulated in subjects treated
with rIL-21.
Conclusions Administration of rIL-21 resulted in activation of multiple cell types and immune response pathways. The changes observed
in serum proteins were consistent with coincident processes of lymphoid and myeloid cell activation and trafficking, and acute
phase response.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
109.
Petter D. Jenssen Tore Krogstad Adam M. Paruch Trond Mæhlum Kinga Adam Carlos A. Arias Arve Heistad Lena Jonsson Daniel Hellström Hans Brix Markku Yli-Halla Lasse Vråle Matti Valve 《Ecological Engineering》2010,36(12):1651-1659
Nine filter beds have been constructed in the Nordic countries, Denmark, Finland, Norway and Sweden. Filter beds consist of a septic tank followed by an aerobic pre-treatment biofilter and a subsequent saturated flow grass-covered filter. Thus, filter beds are similar to subsurface flow constructed wetlands with pre-treatment biofilters, but do not have wetland plants with roots submerged into the saturated filter. All saturated filters contain Filtralite®P, a light-weight expanded clay aggregate possessing high phosphorus sorption capacity. The filter bed systems showed stable and consistent performance during the testing period of 3 years. Removal of organic matter measured as biochemical oxygen demand (BOD) was >80%, total phosphorus (TP) >94% and total nitrogen (TN) ranged from 32 to 66%. Effluent concentrations of fecal indicator bacteria met the European bathing water quality criteria in all systems. One system was investigated for virus removal and somatic viruses were not detected in the effluent. The investigations revealed that the majority of the BOD and nitrogen removal occurred in the pre-treatment filters and the phosphorus and bacteria removal was more prominent in the saturated filters. The saturated filters could be built substantially smaller than the current design guidelines without sacrificing treatment performance. The used filter material met the Norwegian regulations for reuse in agriculture with respect to heavy metals, bacteria and parasites. When saturated with phosphorus, the light-weight aggregate, Filtralite®P used in the saturated bed is a suitable phosphorus fertilizer and additionally has a liming effect. 相似文献
110.