Abstract:
:The determination of molecular masses from barometric sedimentation profiles, a main topic in ultracentrifugal analysis, is thought to be quantitatively correct for non-interacting particles. Whereas this expectation is justified for uncharged colloids or macromolecules at low volume fractions, early ultracentrifugation studies on charged particles had already indicated that the obtained masses might be much too low. More recently, expanded sedimentation profiles have been observed for charged particles, sometimes inflated by orders of magnitude relative to the barometric prediction, which highlights a shortcoming in our understanding of centrifugation of even very dilute charged species. Theory and simulations, anticipated by various authors, now propose that strongly non-barometric sedimentation profiles might be caused by an internal macroscopic electric field that, even for non-interacting particles, significantly decreases the buoyant particle mass. The existence of this field and its intriguing consequences still lack experimental verification. Here we report ultracentrifugation experiments on charged colloidal silica spheres, showing both the existence of such a macroscopic electric field and its drastic effects on the sedimentation profiles of very dilute dispersions at low ionic strength.
journal_name
Naturejournal_title
Natureauthors
Raşa M,Philipse APdoi
10.1038/nature02672keywords:
subject
Has Abstractpub_date
2004-06-24 00:00:00pages
857-60issue
6994eissn
0028-0836issn
1476-4687pii
nature02672journal_volume
429pub_type
杂志文章相关文献
NATURE文献大全abstract::The 2.2 A crystal structure of activated rod transducin, Gt alpha.GTP gamma S, shows the bound GTP gamma S molecule occluded deep in a cleft between a domain structurally homologous to small GTPases and a helical domain unique to heterotrimeric G proteins. The structure, when combined with biochemical and genetic stud...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/366654a0
更新日期:1993-12-16 00:00:00
abstract::The satellites Rhea and Dione orbit within the magnetosphere of Saturn, where they are exposed to particle irradiation from trapped ions. A similar situation applies to the galilean moons Europa, Ganymede and Callisto, which reside within Jupiter's radiation belts. All of these satellites have surfaces rich in water i...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/40348
更新日期:1997-07-03 00:00:00
abstract::Anti-inflammatory glucocorticoids inhibit prostaglandin (PG) biosynthesis by preventing arachidonic acid release from phospholipids rather than inhibiting the cyclooxygenase. As in other cells, this steroid action depends on receptor occupation and de novo protein/RNA biosynthesis. We have previously shown in guinea p...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/287147a0
更新日期:1980-09-11 00:00:00
abstract::Juxtaposition between endoplasmic reticulum (ER) and mitochondria is a common structural feature, providing the physical basis for intercommunication during Ca(2+) signalling; yet, the molecular mechanisms controlling this interaction are unknown. Here we show that mitofusin 2, a mitochondrial dynamin-related protein ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature07534
更新日期:2008-12-04 00:00:00
abstract::The neural crest, a source of many different cell types in vertebrate embryos, has not been identified in other chordates. Current opinion therefore holds that neural crest cells were a vertebrate innovation. Here we describe a migratory cell population resembling neural crest cells in the ascidian urochordate Ecteina...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature02975
更新日期:2004-10-07 00:00:00
abstract::A novel, structurally distinct POU-domain protein has been identified that inhibits activation by another positive POU-domain regulator of neuron-specific transcription units. Two Drosophila POU-domain proteins, I-POU and Cf1-a, are coexpressed in overlapping subsets of neurons during development. Because I-POU lacks ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/350577a0
更新日期:1991-04-18 00:00:00
abstract::Plant respiration results in an annual flux of carbon dioxide (CO2) to the atmosphere that is six times as large as that due to the emissions from fossil fuel burning, so changes in either will impact future climate. As plant respiration responds positively to temperature, a warming world may result in additional resp...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature17142
更新日期:2016-03-31 00:00:00
abstract::The biogenic amine transporters (BATs) regulate endogenous neurotransmitter concentrations and are targets for a broad range of therapeutic agents including selective serotonin reuptake inhibitors (SSRIs), serotonin-noradrenaline reuptake inhibitors (SNRIs) and tricyclic antidepressants (TCAs). Because eukaryotic BATs...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature12648
更新日期:2013-11-07 00:00:00
abstract::Long-term reconstitution of the lymphohaematopoietic cells of a mouse after lethal irradiation requires the transplantation of at least (5-10) x 10(3) bone marrow cells. Several cell-separation techniques based on cell-surface characteristics have been used in attempts to identify the pluripotent haematopoietic stem c...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/347188a0
更新日期:1990-09-13 00:00:00
abstract::Bioluminescent symbioses range from facultative associations to highly adapted, apparently obligate ones. The family Anomalopidae (flashlight fishes) encompasses five genera of tropical reef fishes that have large suborbital light organs. The suborder Ceratioidei (deep-sea anglerfishes) contains 11 families. In nine o...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/363154a0
更新日期:1993-05-13 00:00:00
abstract::RNA ligases have essential roles in many cellular processes in eukaryotes, archaea and bacteria, including in RNA repair and stress-induced splicing of messenger RNA. In archaea and eukaryotes, RNA ligases also have a role in transfer RNA splicing to generate functional tRNAs required for protein synthesis. We recentl...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature13284
更新日期:2014-07-03 00:00:00
abstract::Plant growth and development is regulated by a structurally unrelated collection of small molecules called plant hormones. During the last 15 years the number of known plant hormones has grown from five to at least ten. Furthermore, many of the proteins involved in plant hormone signalling pathways have been identifie...
journal_title:Nature
pub_type: 杂志文章,评审
doi:10.1038/nature08122
更新日期:2009-06-25 00:00:00
abstract::Phytoplankton size structure is acknowledged as a fundamental property determining energy flow through 'microbial' or 'herbivore' pathways. The balance between these two pathways determines the ability of the ecosystem to recycle carbon within the upper layer or to export it to the ocean interior. Small cells are usua...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35066560
更新日期:2001-03-15 00:00:00
abstract::Transcriptional activator proteins (activators) function, at least in part, by increasing preinitiation complex assembly (for reviews see refs 1-4). Previous studies have shown that an acidic activator forms a contact with the general transcription factor TFIIB (refs 5-7) and recruits it into the preinitiation complex...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/371717a0
更新日期:1994-10-20 00:00:00
abstract::Perfusion chromatography is a technique based on fluid dynamics for reducing stagnant mobile phase mass transfer in liquid chromatography. This is achieved by using supports with large pores that allow mobile phase to flow through particles. ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/350634a0
更新日期:1991-04-18 00:00:00
abstract::The idea that natural selection on genes might be detected using only a single genome has been put forward by Plotkin and colleagues, who present a method that they claim can detect selection without the need for comparative data and which, if correct, would confer greater power of analysis with less information. Here...
journal_title:Nature
pub_type: 评论,杂志文章
doi:10.1038/nature03221
更新日期:2005-01-20 00:00:00
abstract::The spectral purity of an oscillator is central to many applications, such as detecting gravity waves, defining the second, ground-state cooling and quantum manipulation of nanomechanical objects, and quantum computation. Recent proposals suggest that laser oscillators which use very narrow optical transitions in atom...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature10920
更新日期:2012-04-04 00:00:00
abstract::Sex is expensive. A population of females that reproduce asexually should prima facie have twice the growth rate of an otherwise equivalent anisogamous sexual population lacking paternal care, or a population with modes of paternal care that can be co-opted by parthenogenetic females. The two leading theories for the ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35079578
更新日期:2001-06-07 00:00:00
abstract::Bone has recently emerged as a pleiotropic endocrine organ that secretes at least two hormones, FGF23 and osteocalcin, which regulate kidney function and glucose homeostasis, respectively. These findings have raised the question of whether other bone-derived hormones exist and what their potential functions are. Here ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature21697
更新日期:2017-03-16 00:00:00
abstract::Sex roles are typically thought of as being fixed for a given species. In most animals males compete for females, whereas the females are more reluctant to mate. Therefore sexual selection usually acts most strongly on males. This is explained by males having a higher potential reproductive rate than females, leading ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature02562
更新日期:2004-06-03 00:00:00
abstract::The genetic relationships of human populations have been studied by comparing gene frequency data for protein and blood-group loci of different populations. DNA analysis now promises to be more informative since not only do the DNA coding sequences have more variation than their corresponding proteins but, in addition...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/319491a0
更新日期:1986-02-06 00:00:00
abstract::Globular star clusters are compact and massive stellar systems old enough to have witnessed the entire history of our Galaxy, the Milky Way. Although recent results suggest that their formation may have been more complex than previously thought, they still are the best approximation to a stellar population formed over...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature08581
更新日期:2009-11-26 00:00:00
abstract::The Gulf Stream transports large amounts of heat from the tropics to middle and high latitudes, and thereby affects weather phenomena such as cyclogenesis and low cloud formation. But its climatic influence, on monthly and longer timescales, remains poorly understood. In particular, it is unclear how the warm current ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature06690
更新日期:2008-03-13 00:00:00
abstract::Phosphorylation of membrane components is thought to be an important process in membrane function. Phosphorylated proteins and a special class of phospholipids, the (poly)phosphoinositides (poly PI), are implicated in the regulation of membrane permeability and synaptic transmission in neurones. For many years, protei...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/286623a0
更新日期:1980-08-07 00:00:00
abstract::MANY ferromanganese minerals have been found in marine manganese deposits. There have been terminological and intrinsic problems in accurately defining the constituents of manganese nodules(1), but 10-A manganite and delta-MnO(2) which are often compared with todorokite and birnessite seem to be the only major constit...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/279411a0
更新日期:1979-05-31 00:00:00
abstract::Psoriasis is a chronic inflammatory skin disorder that affects approximately 2-3% of the population worldwide and has severe effects on patients' physical and psychological well-being. The discovery that psoriasis is an immune-mediated disease has led to more targeted, effective therapies; recent advances have focused...
journal_title:Nature
pub_type: 杂志文章,多中心研究,随机对照试验
doi:10.1038/nature14175
更新日期:2015-05-14 00:00:00
abstract::The planet in the system HD209458 is the first one for which repeated transits across the stellar disk have been observed. Together with radial velocity measurements, this has led to a determination of the planet's radius and mass, confirming it to be a gas giant. But despite numerous searches for an atmospheric signa...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature01448
更新日期:2003-03-13 00:00:00
abstract::Understanding ice sheet behaviour in the geological past is essential for evaluating the role of the cryosphere in the climate system and for projecting rates and magnitudes of sea level rise in future warming scenarios1-4. Although both geological data5-7 and ice sheet models3,8 indicate that marine-based sectors of ...
journal_title:Nature
pub_type: 历史文章,杂志文章
doi:10.1038/s41586-018-0501-8
更新日期:2018-09-01 00:00:00
abstract:: ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/d41586-018-07692-4
更新日期:2018-12-01 00:00:00
abstract::The four-chambered mammalian heart develops from two fields of cardiac progenitor cells distinguished by their spatiotemporal patterns of differentiation and contributions to the definitive heart. The first heart field differentiates earlier in lateral plate mesoderm, generates the linear heart tube and ultimately giv...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature10094
更新日期:2011-05-29 00:00:00