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1.
Science ; 371(6526): 296-300, 2021 01 15.
Article in English | MEDLINE | ID: mdl-33446558

ABSTRACT

Long-lived excited states of interacting quantum systems that retain quantum correlations and evade thermalization are of great fundamental interest. We create nonthermal states in a bosonic one-dimensional (1D) quantum gas of dysprosium by stabilizing a super-Tonks-Girardeau gas against collapse and thermalization with repulsive long-range dipolar interactions. Stiffness and energy-per-particle measurements show that the system is dynamically stable regardless of contact interaction strength. This enables us to cycle contact interactions from weakly to strongly repulsive, then strongly attractive, and finally weakly attractive. We show that this cycle is an energy-space topological pump (caused by a quantum holonomy). Iterating this cycle offers an unexplored topological pumping method to create a hierarchy of increasingly excited prethermal states.

2.
Phys Rev Lett ; 120(23): 230401, 2018 Jun 08.
Article in English | MEDLINE | ID: mdl-29932688

ABSTRACT

We demonstrate the tuning of the magnetic dipole-dipole interaction (DDI) within a dysprosium Bose-Einstein condensate by rapidly rotating the orientation of the atomic dipoles. The tunability of the dipolar mean-field energy manifests as a modified gas aspect ratio after time-of-flight expansion. We demonstrate that both the magnitude and the sign of the DDI can be tuned using this technique. In particular, we show that a magic rotation angle exists at which the mean-field DDI can be eliminated, and at this angle, we observe that the expansion dynamics of the condensate is close to that predicted for a nondipolar gas. The ability to tune the strength of the DDI opens new avenues toward the creation of exotic soliton and vortex states as well as unusual quantum lattice phases and Weyl superfluids.

3.
Neuroreport ; 29(10): 863-869, 2018 07 04.
Article in English | MEDLINE | ID: mdl-29742620

ABSTRACT

Depression is present in a large proportion of patients suffering from chronic pain, and yet the underlying mechanisms remain to be elucidated. Neuroligins (NLs), as a family of cell-adhesion proteins, are involved in synaptic formation and have been linked to various neuropsychiatric disorders. Here, we studied the alterations in NL1 and NL2 in the medial prefrontal cortex (mPFC), the anterior cingulate cortex (ACC), and the hippocampus in a rat model of neuropathic pain-induced depression, and whether ketamine, a rapid and robust antidepressant, could restore these abnormalities. In the present study, we found that spared nerve injury induced significant mechanical allodynia and subsequent depressive-like symptoms, along with decreased NL1 and increased NL2 in the mPFC, decreased NL1 in the ACC, and decreased NL2 in the hippocampus. In addition, brain-derived neurotrophic factor (BDNF) was reduced in these brain regions. It is noteworthy that ketamine (10 mg/kg) relieved neuropathic pain-induced depressive behaviors and restored alterations of BDNF and NLs in the mPFC and the hippocampus at 24 h and 72 h after the administration of ketamine, but only restored BDNF in the ACC. In conclusion, NLs showed diverse changes in different brain regions in the rat model of neuropathic pain-induced depression, which could be reversed differentially by the administration of ketamine.


Subject(s)
Antidepressive Agents/pharmacology , Behavior, Animal/drug effects , Depression/drug therapy , Ketamine/pharmacology , Neuralgia/drug therapy , Animals , Brain-Derived Neurotrophic Factor/metabolism , Depression/metabolism , Disease Models, Animal , Gyrus Cinguli/drug effects , Gyrus Cinguli/metabolism , Hippocampus/drug effects , Hippocampus/metabolism , Hyperalgesia/drug therapy , Hyperalgesia/metabolism , Male , Neuralgia/metabolism , Prefrontal Cortex/drug effects , Prefrontal Cortex/metabolism , Rats, Sprague-Dawley
4.
Opt Express ; 25(14): 16783-16794, 2017 Jul 10.
Article in English | MEDLINE | ID: mdl-28789179

ABSTRACT

Volume imaging based on a fast focus-tunable lens (FTL) allows three-dimensional (3D) observation within milliseconds by extending the depth-of-field (DOF) with sub-micrometer transverse resolution on optical sectioning microscopes. However, the previously published DOF extensions were neither axially uniform nor fit with theoretical prediction. In this work, complete theoretical treatments of focus extension with confocal and various multiphoton microscopes are established to correctly explain the previous results. Moreover, by correctly placing the FTL and properly adjusting incident beam diameter, a uniform DOF is achieved in which the actual extension nicely agrees with the theory. Our work not only provides a theoretical platform for volumetric imaging with FTL but also demonstrates the optimized imaging condition.

5.
Neurotox Res ; 30(4): 593-605, 2016 11.
Article in English | MEDLINE | ID: mdl-27443555

ABSTRACT

Ketamine, a common anesthetic used for pediatric patients, has been shown to induce neurotoxicity and alter adolescent behaviors in rats when administered during neonatal period. However, the mechanisms underlying this kind of neurotoxicity remain largely to be determined. Herein, we studied whether the reactive oxygen species (ROS) due to the increased NOX2 mediates loss of phenotype of PV interneurons and thus contributes to long-term cognitive impairments after repeated ketamine exposures. Sprague-Dawley male rat pups received a daily administration of ketamine intraperitoneally (75 mg/kg) from postnatal day 6 (P6) to P8 for three consecutive days. For the interventional study, pups were treated with a NADPH oxidase inhibitor, apocynin (Apo). Learning and memory abilities were tested by the open field, fear conditioning, and Morris water maze on P40, P42-44, and P50-56, respectively. For histological and biochemical assays, a separate cohort of rats was killed on P9 or P60, and the brain tissues were harvested. Our results showed the upregulation of 8-OHdG and gp91/NOX2 and downregulation of PV and glutamic acid decarboxylase 67 (GAD67) after repeated ketamine exposures, which co-occurred with the long-term cognitive impairments as evidenced by the decreased freezing time to context. However, Apo treatment attenuated these abnormalities. Our results suggest that oxidative damage, probably due to the increased NOX2, mediates loss of phenotype of PV interneurons and thus contributes to long-term cognitive impairments after repeated ketamine exposures. Moreover, the inhibition of NADPH oxidase may protect against cognitive dysfunction.


Subject(s)
Brain/drug effects , Cognitive Dysfunction/chemically induced , Interneurons/drug effects , Ketamine/toxicity , Prenatal Exposure Delayed Effects , Reactive Oxygen Species/metabolism , Acetophenones/pharmacology , Animals , Anxiety , Brain/growth & development , Brain/metabolism , Brain/pathology , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Cohort Studies , Disease Models, Animal , Enzyme Inhibitors/pharmacology , Female , Interneurons/metabolism , Interneurons/pathology , Male , Maze Learning/physiology , Membrane Glycoproteins/metabolism , Mitochondria/drug effects , Mitochondria/metabolism , NADPH Oxidase 2 , NADPH Oxidases/metabolism , Parvalbumins/metabolism , Pregnancy , Random Allocation , Rats, Sprague-Dawley
6.
J Vis Exp ; (107)2016 Jan 03.
Article in English | MEDLINE | ID: mdl-26780248

ABSTRACT

Plasmonics, which are based on the collective oscillation of electrons due to light excitation, involve strongly enhanced local electric fields and thus have potential applications in nonlinear optics, which requires extraordinary optical intensity. One of the most studied nonlinearities in plasmonics is nonlinear absorption, including saturation and reverse saturation behaviors. Although scattering and absorption in nanoparticles are closely correlated by the Mie theory, there has been no report of nonlinearities in plasmonic scattering until very recently. Last year, not only saturation, but also reverse saturation of scattering in an isolated plasmonic particle was demonstrated for the first time. The results showed that saturable scattering exhibits clear wavelength dependence, which seems to be directly linked to the localized surface plasmon resonance (LSPR). Combined with the intensity-dependent measurements, the results suggest the possibility of a common mechanism underlying the nonlinear behaviors of scattering and absorption. These nonlinearities of scattering from a single gold nanosphere (GNS) are widely applicable, including in super-resolution microscopy and optical switches. In this paper, it is described in detail how to measure nonlinearity of scattering in a single GNP and how to employ the super-resolution technique to enhance the optical imaging resolution based on saturable scattering. This discovery features the first super-resolution microscopy based on nonlinear scattering, which is a novel non-bleaching contrast method that can achieve a resolution as low as l/8 and will potentially be useful in biomedicine and material studies.


Subject(s)
Gold/chemistry , Metal Nanoparticles/chemistry , Surface Plasmon Resonance/methods , Electrons , Light , Nonlinear Dynamics , Optical Imaging/methods , Optics and Photonics , Scattering, Radiation
7.
Opt Express ; 22(21): 26016-22, 2014 Oct 20.
Article in English | MEDLINE | ID: mdl-25401635

ABSTRACT

Nonlinear plasmonics has attracted a lot of interests due to its wide applications. Recently, we demonstrated saturation and reverse saturation of scattering from a single plasmonic nanoparticle, which exhibits extremely narrow side lobes and central peaks in scattering images [ACS Photonics 1(1), 32 (2014)]. It is desirable to extract the reversed saturated part to further enhance optical resolution. However, such separation is not possible with conventional confocal microscope. Here we combine reverse saturable scattering and saturated excitation (SAX) microscopy. With quantitative analyses of amplitude and phase of SAX signals, unexpectedly high-order nonlinearities are revealed. Our result provides greatly reduced width in point spread function of scattering-based optical microscopy. It will find applications in not only nonlinear material analysis, but also high-resolution biomedical microscopy.


Subject(s)
Light , Materials Testing/methods , Microscopy, Fluorescence/methods , Scattering, Radiation , Fluorescence
8.
Shanghai Kou Qiang Yi Xue ; 22(6): 623-7, 2013 Dec.
Article in Chinese | MEDLINE | ID: mdl-24469122

ABSTRACT

PURPOSE: To construct a recombinant plasmid containing the upstream of fimC and downstream of fimE of Porphyromonas gingivalis, designated as pPHU281-C-Spec-E, which may be further used to knock out fimCDE gene to determine the role of FimCDE in the infection by P. gingivalis. METHODS: DNA fragments were generated by PCR with the genomic DNA of P. gingivalis strain ATCC 33277 as the template. The upstream fragment of fimC (fragment C) and downstream fragment of fimE (fragment E) were cloned into the suicide plasmid pPHU281 to generate plasmid pPHU281-C-E. The spectinomycin resistance gene was inserted between fragment C and E to construct plasmid Pphu281-C-Spec-E. The recombinant plasmid was verified by restriction enzyme digestion and DNA sequencing. RESULTS: The recombinant plasmid pPHU281-C-Spec-E was successfully constructed, which was ready for generation of FimCDE-knockout mutant of P. gingivalis. CONCLUSIONS: The recombinant plasmid pPHU281-C-Spec-E is a tool for construction of FimCDE deficient mutant of P. gingivalis. Supported by National Natural Science Foundation of China (81070839). Team Project of Medical Leaders in Talent and Innovation of Jiangsu Province (LJ201110), Science and Technology Development Plan of Nanjing City(YKK06115) and Medical Science and Technology Development Project of Nanjing City(ZKX1030).


Subject(s)
Fimbriae Proteins , Plasmids , Porphyromonas gingivalis , China , Humans
9.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 47(11): 671-4, 2012 Nov.
Article in Chinese | MEDLINE | ID: mdl-23302429

ABSTRACT

OBJECTIVE: To construct the recombinant plasmid pPHU281_A_Spec_B, which knock out Porphyrmonas gingivalis (Pg) FimA gene. METHODS: Genomic DNA was extracted from PgATCC33277 which was cultured in anaerobic condition. The upstream and downstream gene of FimA was cloned from Pg genenomic DNA with specific restriction sites by polymerase chain reaction. Suicide vector pPHU281 was inserted by three fragments: upstream, downstream of FimA gene and spectinomycin resistance gene. The recombinant plasmid was confirmed by electrophoresis and sequenced after amplification in compentent cells DH-5α. RESULTS: The gene sequence was identified by DNA sequencing analysis. The recombinant plasmid pPHU281_A_Spec_B was successfully constructed. CONCLUSIONS: The recombinant plasmid pPHU281_A_Spec_B was constructed, which may be used for the constructon of FimA deficient Pg.


Subject(s)
Fimbriae Proteins/genetics , Genes, Bacterial , Plasmids/genetics , Porphyromonas gingivalis/genetics , Base Sequence , DNA, Bacterial/genetics , Gene Knockout Techniques , Genetic Vectors , Recombinant Proteins/genetics , Sequence Analysis, DNA
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