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1.
Subcutaneous tissue fibroblast cytoskeletal remodeling induced by acupuncture: evidence for a mechanotransduction-based mechanism 总被引:5,自引:0,他引:5
Langevin HM Bouffard NA Badger GJ Churchill DL Howe AK 《Journal of cellular physiology》2006,207(3):767-774
Acupuncture needle rotation has been previously shown to cause specific mechanical stimulation of subcutaneous connective tissue. This study uses acupuncture to investigate the role of mechanotransduction-based mechanisms in mechanically-induced cytoskeletal remodeling. The effect of acupuncture needle rotation was quantified by morphometric analysis of mouse tissue explants imaged with confocal microscopy. Needle rotation induced extensive fibroblast spreading and lamellipodia formation within 30 min, measurable as an increased in cell body cross sectional area. The effect of rotation peaked with two needle revolutions and decreased with further increases in rotation. Significant effects of rotation were present throughout the tissue, indicating the presence of a response extending laterally over several centimeters. The effect of rotation with two needle revolutions was prevented by pharmacological inhibitors of actomyosin contractility (blebbistatin), Rho kinase (Y-27632 and H-1152), and Rac signaling. The active cytoskeletal response of fibroblasts demonstrated in this study constitutes an important step in understanding cellular mechanotransduction responses to externally applied mechanical stimuli in whole tissue, and supports a previously proposed model for the mechanism of acupuncture involving connective tissue mechanotransduction. 相似文献
2.
A computer simulation model of human airborne movement is described. The body is modelled as 11 rigid linked segments with 17 degrees of freedom which are chosen with a view to modelling twisting somersaults. The accuracy of the model is evaluated by comparing the simulation values of the angles describing somersault, tilt and twist with the corresponding values obtained from film data of nine twisting somersaults. The maximum deviations between simulation and film are found to be 0.04 revolutions for somersault, seven degrees for tilt and 0.12 revolutions for twist. It is shown that anthropometric measurement errors, from which segmental inertia parameters are calculated, have a small effect on a simulation, whereas film digitization errors can account for a substantial part of the deviation between simulation and film values. 相似文献
3.
C. Allègre 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》1999,354(1392):1915-1919
The 20th century has been a century of scientific revolutions for many disciplines: quantum mechanics in physics, the atomic approach in chemistry, the nonlinear revolution in mathematics, the introduction of statistical physics. The major breakthroughs in these disciplines had all occurred by about 1930. In contrast, the revolutions in the so-called natural sciences, that is in the earth sciences and in biology, waited until the last half of the century. These revolutions were indeed late, but they were no less deep and drastic, and they occurred quite suddenly. Actually, one can say that not one but three revolutions occurred in the earth sciences: in plate tectonics, planetology and the environment. They occurred essentially independently from each other, but as time passed, their effects developed, amplified and started interacting. These effects continue strongly to this day. 相似文献
4.
《Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences》2010,41(2):135-145
This paper examines the production and circulation of astrological prognostications regarding the illness and death of kings, princes, and popes in the Italian Renaissance (ca. 1470–1630). The distribution and consumption of this type of astrological information was often closely linked to the specific political situation in which they were produced. Depending on the astrological techniques used (prorogations, interrogations, or annual revolutions), and the media in which they appeared (private letters or printed prognostica) these prognostications fulfilled different functions in the information economy of Renaissance Italy. Some were used to legitimise the rule of a political leader, others to do just the opposite. Astrological prorogations and interrogations were often used to plan military and political strategies in case of the illness or death of a political leader, while astrological prognostications were generally written to promote certain political leaders while undermining others. While certainly often partisan to this game, astrologers, for their part, worked within a very well established tradition that gave authority to their forecasts. This paper argues that, as indicators of deeper political tensions otherwise not always explicitly manifest, these prognostications are privileged sources of information providing a better understanding of the political history of the period. 相似文献
5.
David Parker 《Biology & philosophy》2018,33(3-4):17
The terms “paradigm” and “paradigm shift” originated in “The Structure of Scientific Revolutions” by Thomas Kuhn. A paradigm can be defined as the generally accepted concepts and practices of a field, and a paradigm shift its replacement in a scientific revolution. A paradigm shift results from a crisis caused by anomalies in a paradigm that reduce its usefulness to a field. Claims of paradigm shifts and revolutions are made frequently in the neurosciences. In this article I will consider neuroscience paradigms, and the claim that new tools and techniques rather than crises have driven paradigm shifts. I will argue that tool development has played a minor role in neuroscience revolutions. 相似文献
6.
Zoltan Barany 《Ethnic and racial studies》2013,36(3):515-531
Most of Eastern Europe's five‐to‐seven‐million Roma (Gypsies) welcomed the revolutions of 1989 only to realize that the post‐communist era brought mixed blessing to them. Although since then their political and cultural marginalization had diminished, their social and economic circumstances had clearly deteriorated in East Central Europe and the Balkans alike. The only exception to this rule appears to be the newly independent Republic of Macedonia, where the Roma's conditions in many respects are far superior to those of their counterparts elsewhere in the region. There are several reasons for this phenomenon. In the economic realm the Macedonian Roma's situation has also worsened (although still much better than that of the Roma in other Balkan states) but not as a result of ethnic discrimination but owing to the economic hardships accompanying the post‐communist transitions. In the political sphere, the Roma in Macedonia have benefited from a state whose representatives are willing to rise above sympathetic rhetoric and take concrete steps to alleviate their problems as well as from relatively well organized Romani political parties. Most important, however, are the differences between societal attitudes towards the Roma in Macedonia and elsewhere in Eastern Europe. In Macedonia the Roma's relations with the dominant ethnic group (Macedonians) are primarily characterized by ‘peaceful coexistence’ rather than tension and animosity. Moreover, Romani communities in Macedonia are less isolated from non‐Roma both culturally and socio‐economically. This state of affairs is the result of a number of related factors, most important of which are that the Romani community does not represent a threat to Macedonians given their numerical weakness and lack of political clout in contradistinction to the very real threat posed by the ethnic Albanian community in the country. In turn, the Roma's relations to ethnic Albanians and Turks remain relatively agreeable as well. 相似文献
7.
One of the central goals of ecology is to predict the distribution and abundance of organisms. Here, we show that, in ecosystems of high biodiversity, the outcome of multispecies competition can be fundamentally unpredictable. We consider a competition model widely applied in phytoplankton ecology and plant ecology in which multiple species compete for three resources. We show that this competition model may have several alternative outcomes, that the dynamics leading to these alternative outcomes may exhibit transient chaos, and that the basins of attraction of these alternative outcomes may have an intermingled fractal geometry. As a consequence of this fractal geometry, it is impossible to predict the winners of multispecies competition in advance. 相似文献
8.
Three groups of mice, normally fed, fasted and fed after a fasting period are injected intravenously with either 1- or 2-14C acetate. The respiratory 14CO2 as well as that of the liver, the adipose tissue and the carcass are collected after 3 min and the radioactivity measured. A determination is also made of the radioactivity of the tissue fatty acids and, for two groups of mice, of the circulating glucose. A calculation is suggested by which the number of revolutions performed by the acetate C in the Krebs cycle before it is transformed into CO2 can be deduced. The results suggest that the Krebs cycle is very open, that the acetate C found in the glucose has already broken away from the cycle after one revolution and that the C which appears in the form of CO2 has performed an average of only 2.8 to 3.6 revolutions. The results are evaluated as a function of the experimental conditions chosen. 相似文献
9.
When the body is infected, it mounts an acute inflammatory response to rid itself of the pathogens and restore health. Uncontrolled acute inflammation due to infection is defined clinically as sepsis and can culminate in organ failure and death. We consider a three-dimensional ordinary differential equation model of inflammation consisting of a pathogen, and two inflammatory mediators. The model reproduces the healthy outcome and diverse negative outcomes, depending on initial conditions and parameters. We analyze the various bifurcations between the different outcomes when key parameters are changed and suggest various therapeutic strategies. We suggest that the clinical condition of sepsis can arise from several distinct physiological states, each of which requires a different treatment approach. 相似文献
10.
We have developed a novel model to study the correlated evolution of behavioural and morphophysiological traits in response to selection for increased locomotor activity. We used selective breeding to increase levels of voluntary wheel running in four replicate lines of laboratory house mice, Mus domesticus, with four random-bred lines maintained as controls. The experiment presented here tested for correlated behavioural responses in the wheel-cage complex, with wheels either free to rotate or locked (environmental factor). After 13 generations, mice from selected lines ran 2.2 times as many revolutions/day as controls on days 5 and 6 of initial exposure to wheels (10 826 versus 4890 revolutions/day, corresponding to 12.1 and 5.5 km/day, respectively). This increase was caused primarily by mice from selected lines running faster, not more minutes per day. Focal-animal observations confirmed that the increase in revolutions/day involved more actual running (or climbing in locked wheels), not an increase in coasting (or hanging). Not surprisingly, access to free versus locked wheels had several effects on behaviour, including total time spent in wheels, sniffing and biting. However, few behaviours showed statistically significant differences between the selected and control lines. Selection did not increase the total time spent in wheels (either free or locked), the frequency of nonlocomotor activities performed in the wheels, nor the amount of locomotor activity in cages attached to the wheels; as well, selection did not decrease the amount of time spent sleeping. Thus, wheel running is, at the genetic level, a largely independent axis of behaviour. Moreover, the genetic architecture of overall wheel running and its components seem conducive to increasing total distance moved without unduly increasing energy or time-related costs. The selection experiment also offers a new approach to study the proximate mechanisms of wheel-running behaviour itself. For example, frequencies of sniffing and wire biting were reduced in selected females but not males. This result suggests that motivation or function of wheel running may differ between the sexes. Copyright 1999 The Association for the Study of Animal Behaviour. 相似文献
11.
Andrea Macaluso Archie Young Katie S Gibb David A Rowe Giuseppe De Vito 《Journal of applied physiology》2003,95(6):2544-2553
Cycling on a mechanically braked cycle ergometer was used as a novel approach to compare the effects of three different 16-wk resistance-training programs on isometric force, power output, and selected functional abilities in 31 healthy 65- to 74-yr-old women. Training was conducted three times per week. During each session, individuals of the speed group performed 8 sets of 16 pedal revolutions at 40% of the maximal resistance to complete two revolutions (2 RM); strength group performed 8 sets of 8 revolutions at 80% of 2 RM; and combination group performed 4 sets of 16 revolutions at 40% and 4 sets of 8 revolutions at 80% of 2 RM. During each set, all participants were required to pedal as fast as possible with a 2-min interval between sets. All training groups significantly increased force, power, and functional abilities (maximal treadmill walking speed, vertical jumping, and box stepping) at week 8 (in the range from 6.5 to 20.8%) with no further improvement at week 16 (except maximal treadmill walking speed), but no significant differences were observed between the three groups. The novel approach to performing both low- and high-resistance training, based on the use of a cycle ergometer, has been shown to be effective in improving strength, power, and functional abilities in a group of healthy women. Even fit older women can still improve in functional abilities. Interestingly, the "high-speed" and "low-speed" programs induced an increase in both power and strength of similar magnitude. 相似文献
12.
The unicellular green alga Pleurenterium tumidum Bréb. performs a unique type of circular nuclear migration, wherein the nucleus leaves its central position and starts revolutions in the cortical isthmus area about 10 h after mitosis. This motion lasts for at least 12 h with an average velocity of about 1 h per revolution. Possible force generation modes during circular nuclear migration of Pleurenterium were investigated by application of inhibitors and the use of digital time‐lapse video microscopy. 5′‐Adenylylimidodiphosphate, a nonhydrolyzable nucleotide analogue, retarded or inhibited circular nuclear migration, suggesting that ATPase dependent motor proteins are involved. Ado‐ ciasulfate‐2, a kinesin specific inhibitor, caused displacement of the nucleus, suggesting that the linkage between the microtubule track and the nucleus is lost. The nucleus was still able to move for short distances, but no normal revolutions took place. Erythro‐9‐[3‐(2‐hydroxynonyl)] adenine, a dynein ATPase inhibitor, led to complete inhibition of nuclear revolutions, suggesting a function in force generation also for this molecular motor. In addition, kinesin‐ and dynein‐like proteins were detected in Pleurenterium extracts by Western blotting. The myosin specific inhibitor 2,3‐butanedione 2‐monoxime did not influence circular nuclear migration in Pleurenterium. This result and the absence of actin filaments around the migrating nucleus as depicted by means of microinjection of Alexa phalloidin in the present study indicate that the actin‐myosin system can be excluded from force generation. 相似文献
13.
Shankar Aswani 《Human ecology: an interdisciplinary journal》1999,27(3):417-453
In recent decades, Pacific Region indigenous sea tenure regimes have received considerable attention from social scientists who believe thatmarine-localized common entitlements and fishing practices can aid modern littoral fisheries management. The endorsement of sea tenure institutions as managerial tools, however, has proceeded without adequate consideration of their vulnerability to social and economic changes. The general view held by researchers is that Pacific Island sea tenure regimes are generally undermined by the influence of exogenous forces resulting in an open-access commons. In this article, it is argued that the contemporary transformation of sea tenure regimes emerges not only from exogenous agency, but from a complex set of autochthonous processes. A case study from New Georgia, Solomon Islands, is presented to show how sea tenure regimes can vary within an ethnically and culturally homogeneous region. Three tenure models are presented to show how different pre- and post-European contact regional settlement patterns, localized processes of political expansion and contraction, and dynamic indigenous sociocultural principles have resulted in institutional differences between each sea tenure model. The effect of the market economy on the organizational structure and managerial outcomes of each model also is discussed. 相似文献
14.
Anecdotal,Historical and Critical Commentaries on Genetics: Darwin and Darwinism: The (Alleged) Social Implications of The Origin of Species
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H. Allen Orr 《Genetics》2009,183(3):767-772
Most scientific theories, even revolutionary ones, change the practice of a particular science but have few consequences for culture or society at large. But Darwinism, it has often been said, is different in this respect. Since the publication of The Origin of Species, many have claimed that Darwinism has a number of profound social implications. Here, I briefly consider three of these: the economic, the political, and the religious. I suggest that, for the most part, these supposed implications have been misconstrued or exaggerated. Indeed, it is reasonably clear that the chain of implication sometimes primarily ran in the opposite direction—from, for instance, economics and political theory to Darwinism.THE appearance of The Origin of Species launched one of the greatest, and most justly celebrated, revolutions in the history of science. But in the 150 years since the appearance of Darwin''s book, many scholars, scientists, and pundits have claimed that Darwinism did more than revolutionize biology. Darwinism, they claim, also had a number of social and cultural consequences: economic and political, medical, eugenic, educational, and religious. Some of these consequences are to be applauded and others regretted, but all, it is said, can be traced to important strands of thought in The Origin of Species. One of the ironies of modern history would thus seem to be that the close scientific study of pigeons, mockingbirds, and barnacles could have such consequences.But while the case for the scientific importance of Darwinism is incontestable, the case for its presumed social and cultural consequences is far more complex and, in places, dubious. Here I consider three of these supposed consequences: the economic, the political, and the religious. Because the economic and religious cases have been widely discussed, I focus on the political one. I should note that I am not an expert on economics, political theory, or religion, but a biologist. Perhaps fortunately, then, little that I have to say is new but reflects the efforts of many social scientists and historians. Because their ideas seem little known among biologists, they may be worth recounting here. 相似文献
15.
Manuel Garcia-Herranz Esteban Moro Manuel Cebrian Nicholas A. Christakis James H. Fowler 《PloS one》2014,9(4)
Recent research has focused on the monitoring of global–scale online data for improved detection of epidemics, mood patterns, movements in the stock market political revolutions, box-office revenues, consumer behaviour and many other important phenomena. However, privacy considerations and the sheer scale of data available online are quickly making global monitoring infeasible, and existing methods do not take full advantage of local network structure to identify key nodes for monitoring. Here, we develop a model of the contagious spread of information in a global-scale, publicly-articulated social network and show that a simple method can yield not just early detection, but advance warning of contagious outbreaks. In this method, we randomly choose a small fraction of nodes in the network and then we randomly choose a friend of each node to include in a group for local monitoring. Using six months of data from most of the full Twittersphere, we show that this friend group is more central in the network and it helps us to detect viral outbreaks of the use of novel hashtags about 7 days earlier than we could with an equal-sized randomly chosen group. Moreover, the method actually works better than expected due to network structure alone because highly central actors are both more active and exhibit increased diversity in the information they transmit to others. These results suggest that local monitoring is not just more efficient, but also more effective, and it may be applied to monitor contagious processes in global–scale networks. 相似文献
16.
Human beings are constantly surrounded by uncertainty and change. The question arises how people cope with such uncertainty. To date, most research has focused on the cognitive strategies people adopt to deal with uncertainty. However, especially when uncertainty is due to unpredictable societal events (e.g., economical crises, political revolutions, terrorism threats) of which one is unable to judge the impact on one’s future live, cognitive strategies (like seeking additional information) is likely to fail to combat uncertainty. Instead, the current paper discusses a method demonstrating that people might deal with uncertainty experientially through soft haptic sensations. More specifically, because touching something soft creates a feeling of comfort and security, people prefer objects with softer as compared to harder properties when feeling uncertain. Seeking for softness is a highly efficient and effective tool to deal with uncertainty as our hands are available at all times. This protocol describes a set of methods demonstrating 1) how environmental (un)certainty can be situationally activated with an experiential priming procedure, 2) that the quality of the softness experience (what type of softness and how it is experienced) matters and 3) how uncertainty can be reduced using different methods. 相似文献
17.
Food hoard size varies inversely with body fat levels in Siberian hamsters. If food hoarding only increases when body fat decreases, then hamsters foraging for their food should only increase food hoarding when foraging efforts decrease body fat ("lipostatic hypothesis"); however, if food hoarding increases whenever there is an energy flux away from fat storage, then it should increase regardless of significant body fat decreases ("metabolic hypothesis"). Female Siberian hamsters (Phodopus sungorus) earned food pellets after completion of a programmed number of wheel revolutions (Immobilized Wheel [free access to food], Free Wheel [wheel active, free food], and 10, 50, 100, and 200 revolutions/pellet). Hamsters were killed after 19 days and inguinal, retroperitoneal, and parametrial white adipose tissue (WAT) pads (IWAT, RWAT, and PWAT, respectively) were harvested and carcass composition determined. Food hoard size increased fourfold with the availability of running wheels alone (Free Wheel), increased threefold with low foraging levels (10 and 50 revolutions/pellet), but was nearly abolished at the highest foraging level (200 revolutions/pellet). Surplus food (earned, not eaten or hoarded) was significantly greatest at the lowest level of foraging. As foraging effort increased, PWAT mass decreased the most (<10 revolutions/pellet), while RWAT and IWAT mass only were decreased at the highest foraging effort. Carcass lipid content only was significantly decreased at the highest foraging effort, yet food hoarding was nearly abolished at that level. Collectively, these results demonstrate that body fat levels and food hoarding can be uncoupled with increases in foraging effort. J. Exp. Zool. 289:162-171, 2001. 相似文献
18.
《Ethology : formerly Zeitschrift fur Tierpsychologie》2017,123(1):1-29
Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of ‘model’ species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory – the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life‐history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency. 相似文献
19.
For several decades, conservation landscapes in Sub-Saharan Africa (SSA) have witnessed the intervention of diverse international conservation and development agencies in a bid to promote the conservation agenda. These interventions have seen the application of several models; while the outcomes of some have been sufficiently documented, the intricacies linked to conservation sub-contracting and the outcomes they produce, account for a very negligible fraction of the literature. This knowledge gap represents a constantly ignored but very important contributing factor toward conservation outcomes. To close the gap, this paper takes the case of the Dja Landscape of Cameroon to explore the political ecology of conservation sub-contracting. Specifically, it; (a) explores power manifestations in the conservation sub-contracting process between an international and a local NGO, (b) evaluates their outcomes in the frame of the sustainability of conservation interventions, and (c) examines the twists and turns of the conservation sub-contracting process between an international and a local NGO using a power lens. Qualitative data was generated using key informant interviews (n = 36), expert interviews (n = 7), and focus group discussions (n = 5) in four communities around the North and Western clusters of the Dja Landscape. Using directed content analysis and narratives, the analysis leads us to the following conclusions: Firstly, as a model, conservation sub-contracting holds promise to deliver efficient and relevant interventions, provided the terms of the contract are clear to the parties involved. The flip side is that it renders local NGOs significantly dependent on the former – creating a power dynamic of dominance by funding agencies. Secondly, in sub-contracting, unexpected shifts in the exercise of power occur; therefore, power acquisition and exercise in conservation sub-contracting is not static. Thirdly, conservation sub-contracting is flawed with the observed obscurity of the sub-contractor vis-à-vis the target communities. While the results provide new insights on the switching roles of the potentate and the subordinate in conservation sub-contracting, they call for further studies across SSA to explore the twists and turns linked to sub-contracting. 相似文献
20.
Rebecca McLain Lee Cerveny Kelly Biedenweg David Banis 《Human ecology: an interdisciplinary journal》2017,45(5):585-600
Indigenous peoples, local communities, and other groups can use counter-mapping to make land claims, identify areas of desired access, or convey cultural values that diverge from the dominant paradigm. While sometimes created independently, counter-maps also can be formulated during public participation mapping events sponsored by natural resource planning agencies. Public participation mapping elicits values, uses, and meanings of landscapes from diverse stakeholders, yet individuals and advocacy groups can use the mapping process as an opportunity to make visible strongly held values and viewpoints. We present three cases from the Olympic Peninsula in Washington State to illustrate how stakeholders intentionally used landscape-values mapping workshops to amplify their perspectives in attempts to further political outcomes. We combine geospatial analysis with qualitative data to explore ways that landscape-values mapping were used as a political tool and how social scientists engaged in similar efforts can defend the scientific integrity of results. 相似文献