15 research outputs found
Expansion dynamics of a spherical Bose-Einstein condensate
We experimentally and theoretically observe the expansion behaviors of a
spherical Bose-Einstein condensate. A rubidium condensate is produced in an
isotropic optical dipole trap with an asphericity of 0.037. We measure the
variation of the condensate size during the expansion process. The free
expansion of the condensate is isotropic, which is different from that of the
condensate usually produced in the anisotropic trap. The expansion in the short
time is speeding and then after a long time the expansion velocity
asymptotically approaches a constant value. We derive an analytic solution of
the expansion behavior based on the spherical symmetry, allowing a quantitative
comparison with the experimental measurement. The interaction energy of the
condensate is gradually converted into the kinetic energy at the beginning of
the expansion and the kinetic energy dominates after a long-time expansion. We
obtain the interaction energy of the condensate in the trap by probing the
expansion velocity, which is consistent with the theoretical prediction.Comment: 6 pages, 5 figure
Phase-locking matter-wave interferometer of vortex states
Matter-wave interferometer of ultracold atoms with different linear momenta
has been extensively studied in theory and experiment. The vortex matter-wave
interferometer with different angular momenta is applicable as a quantum sensor
for measuring the rotation, interatomic interaction, geometric phase, etc. Here
we report the first experimental realization of a vortex matter-wave
interferometer by coherently transferring the optical angular momentum to an
ultracold Bose condensate. After producing a lossless interferometer with atoms
only populating the two spin states, we demonstrate that the phase difference
between the interferences in the two spin states is locked on . We also
demonstrate the robustness of this out-of-phase relation, which is independent
of the angular-momentum difference between the two interfering vortex states,
constituent of Raman optical fields and expansion of the condensate. The
experimental results agree well with the calculation from the unitary evolution
of wave packet in quantum mechanics. This work opens a new way to build a
quantum sensor and measure the atomic correlation in quantum gases.Comment: 5 figure
Comparison of Three Mechanical Thrombus Removal Devices in Thrombosed Canine Iliac Arteries
Fitness changes in wild soybean caused by gene flow from genetically modified soybean
Abstract Background Crop-wild hybridization has generated great concerns since gene flow can be an avenue for transgene escape. However, a rather limited number of studies on risk assessment regarding the dispersion of transgenes from GM soybean to populations of its wild relatives have been previously conducted. Results The results of the 3-year experiment demonstrated that hybrids between GM soybeans and wild soybean had lower seed germination and higher seed productivity than GM soybean. Both of these features of hybrid (especially F2 and F3) were similar to those of wild soybean. Furthermore, the foreign protein was stably expressed in hybrid EPSPS positive plants; however, no difference was observed in agronomic measurements between hybrids that are glyphosate sensitive or resistant, homozygous or heterozygous for the transgene, indicating that the presence of the EPSPS transgene does not affect the vigor of hybrid. In contrast, hybridization between GM soybean and wild soybean may have more impact on hybrid growth and fecundity, this increase in biomass and yield confers a potential competition benefit to hybrids. Conclusions Gene flow from GM soybean to wild soybean has the potential to promote the adaptability of hybrids and may increase the possibility of dispersal of transgenes in wild soybean relatives
Phylogenetic Analyses and Transcriptional Survey Reveal the Characteristics, Evolution, and Expression Profile of NBS-Type Resistance Genes in Papaya
Carica papaya maintains an abnormally small but complete NLR family while showing weak disease resistance. To better understand their origin, evolution, and biological function, we identified 59 NLR genes via a customized RGAugury and investigated their characteristics, evolutionary history, and expression profiles based on the improved papaya genome and large-scale RNA-seq data. The results indicated that duplication is a major evolutionary force driving the formation of the papaya NLR family. Synteny analyses of papaya and other angiosperms showed that both insertion and inheritance-derived NLRs are present in papaya. Transcriptome-based expression and network analyses revealed that NLRs are actively involved in biotic stress responses. For example, a papaya-specific inserted TNL was up-regulated strongly by the fungal infection. Both transcriptome and qRT-PCR analyses confirmed the expression divergence of an RNL and an RCNL, a pair of tandem duplication genes involved in different co-expression modules. Furthermore, we observed an inserted gene cluster composed of five duplicated CNLs, showing dosage effects and functional differentiation of disease-resistance genes during evolution. This research will enhance our knowledge of the special NLR family in papaya, which may serve as a model plant for disease-resistance genetic studies
In Situ Proteomic Analysis of Herbicide-Resistant Soybean and Hybrid Seeds via Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry Imaging
Transgenic soybean is the commercial crop with the largest
cultivation
area worldwide. During transgenic soybean cultivation, exogenous genes
may be transferred to wild relatives through gene flow, posing unpredictable
ecological risks. Accordingly, an environmental risk assessment should
focus on fitness changes and underlying mechanisms in hybrids between
transgenic and wild soybeans (Glycine soja). Matrix-assisted laser desorption/ionization-mass spectrometry
imaging (MALDI-MSI) was used for in situ detection and imaging of
protein changes in the seeds of transgenic herbicide-resistant soybean
harboring epsps and pat genes, non-transgenic
soybean, wild soybean, and their F2 hybrid. Protein data
clearly distinguished wild soybeans, while the F2 seeds
had protein characteristics of both parents and were distinguished
from wild soybean seeds. Using UPLC-Q-TOF-MS, 22 differentially expressed
proteins (DEPs) were identified, including 13 specific to wild soybean.
Sucrose synthase and stress response-related DEPs were differentially
expressed in parental and offspring. Differences in these may underpin
the greater adaptability of the latter. MSI revealed DEP distribution
in transgenic, wild, and F2 seeds. Identifying DEPs related
to fitness may elucidate mechanisms underlying fitness differences
among the studied varieties. Our study shows that MALDI-MSI has the
potential to become a visual method for transgenic soybean analysis