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result(s) for
"Liu, J H"
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Blood-derived amyloid-β protein induces Alzheimer’s disease pathologies
The amyloid-β protein (Aβ) protein plays a pivotal role in the pathogenesis of Alzheimer’s disease (AD). It is believed that Aβ deposited in the brain originates from the brain tissue itself. However, Aβ is generated in both brain and peripheral tissues. Whether circulating Aβ contributes to brain AD-type pathologies remains largely unknown. In this study, using a model of parabiosis between APPswe/PS1dE9 transgenic AD mice and their wild-type littermates, we observed that the human Aβ originated from transgenic AD model mice entered the circulation and accumulated in the brains of wild-type mice, and formed cerebral amyloid angiopathy and Aβ plaques after a 12-month period of parabiosis. AD-type pathologies related to the Aβ accumulation including tau hyperphosphorylation, neurodegeneration, neuroinflammation and microhemorrhage were found in the brains of the parabiotic wild-type mice. More importantly, hippocampal CA1 long-term potentiation was markedly impaired in parabiotic wild-type mice. To the best of our knowledge, our study is the first to reveal that blood-derived Aβ can enter the brain, form the Aβ-related pathologies and induce functional deficits of neurons. Our study provides novel insight into AD pathogenesis and provides evidence that supports the development of therapies for AD by targeting Aβ metabolism in both the brain and the periphery.
Journal Article
Hidden lattice instabilities as origin of the conductive interface between insulating LaAlO3 and SrTiO3
2016
The metallic interface between insulating LaAlO
3
and SrTiO
3
opens up the field of oxide electronics. With more than a decade of researches on this heterostructure, the origin of the interfacial conductivity, however, remains unsettled. Here we resolve this long-standing puzzle by atomic-scale observation of electron-gas formation for screening hidden lattice instabilities, rejuvenated near the interface by epitaxial strain. Using atomic-resolution imaging and electron spectroscopy, the generally accepted notions of polar catastrophe and cation intermixing for the metallic interface are discounted. Instead, the conductivity onset at the critical thickness of 4-unit cell LaAlO
3
on SrTiO
3
substrate is accompanied with head-to-head ferroelectric-like polarizations across the interface due to strain-rejuvenated ferroelectric-like instabilities in the materials. The divergent depolarization fields of the head-to-head polarizations cast the interface into an electron reservoir, forming screening electron gas in SrTiO
3
with LaAlO
3
hosting complementary localized holes. The ferroelectric-like polarizations and electron–hole juxtaposition reveal the cooperative nature of metallic LaAlO
3
/SrTiO
3
.
The origin of interfacial conductivity between two insulating oxides, LaAlO
3
and SrTiO
3
, remains elusive despite a long time research. Here, Lee
et al
. report atomic-scale observation of electron-gas formation for screening hidden ferroelectric-like lattice instabilities, discounting the role of polar catastrophe and cation intermixing.
Journal Article
Enhanced energy coupling for indirect-drive fast-ignition fusion targets
2020
One of the most promising approaches to reach a high gain in inertial confinement fusion is the fast ignition scheme. In this scheme, a relativistic electron beam is generated; this passes through the imploded plasma and deposits parts of its energy in the core. However, the large angular spread of the relativistic electron beam and the poorly controlled compression of the target affect realization of the fast ignition technique. Here, we demonstrate that indirectly driven (that is, driven by X-rays generated inside a gold hohlraum) implosions with a ‘high-foot’ and a short-coast time of less than 200 ps allow us to tightly compress the shell. Furthermore, we show the ability to optimize the symmetry of the imploding shell by changing the hohlraum length, successfully tuning a suitable tube-shaped shell to compensate for the large angular spread of the relativistic electron beam and to enhance the electron-to-core coupling efficiency via resistive magnetic fields. Benefiting from those experimental techniques, a significant enhancement in neutron yield was achieved in our indirectly driven fast ignition experiments. These results pave the way towards high-coupling fast ignition experiments with indirectly driven targets similar to those at the National Ignition Facility.
Experiments realizing the indirect-drive fast ignition scheme for inertial confinement fusion are reported. Enabled by a tightly compressed target, an increase of neutron yield is observed.
Journal Article
Phosphorene nanoribbon as a promising candidate for thermoelectric applications
2014
In this work, the electronic properties of phosphorene nanoribbons with different width and edge configurations are studied by using density functional theory. It is found that the armchair phosphorene nanoribbons are semiconducting while the zigzag nanoribbons are metallic. The band gaps of armchair nanoribbons decrease monotonically with increasing ribbon width. By passivating the edge phosphorus atoms with hydrogen, the zigzag series also become semiconducting, while the armchair series exhibit a larger band gap than their pristine counterpart. The electronic transport properties of these phosphorene nanoribbons are then investigated using Boltzmann theory and relaxation time approximation. We find that all the semiconducting nanoribbons exhibit very large values of Seebeck coefficient and can be further enhanced by hydrogen passivation at the edge. Taking pristine armchair nanoribbons and hydrogen-passivated zigzag naoribbons with width
N
= 7, 8, 9 as examples, we calculate the lattice thermal conductivity with the help of phonon Boltzmann transport equation and evaluate the width-dependent thermoelectric performance. Due to significantly enhanced Seebeck coefficient and decreased thermal conductivity, we find that at least one type of phosphorene nanoribbons can be optimized to exhibit very high figure of merit (
ZT
values) at room temperature, which suggests their appealing thermoelectric applications.
Journal Article
Electrical switching of the topological anomalous Hall effect in a non-collinear antiferromagnet above room temperature
by
MacDonald, A. H.
,
Liu, Z. Q.
,
Yan, H.
in
639/301/1005/1007
,
639/301/119/1001
,
639/301/119/997
2018
The anomalous Hall effect is allowed by symmetry in some non-collinear antiferromagnets and is associated with Bloch-band topological features. This topological anomalous Hall effect is of interest in the development of low-power electronic devices, but such devices are likely to demand electrical control over the effect. Here we report the observation of the anomalous Hall effect in high-quality thin films of the cubic non-collinear antiferromagnet Mn
3
Pt epitaxially grown on ferroelectric BaTiO
3
substrates. We demonstrate that epitaxial strain can alter the anomalous Hall conductivity of the Mn
3
Pt films by more than an order of magnitude. Furthermore, we show that the anomalous Hall effect can be turned on and off by applying a small electric field to the BaTiO
3
substrate when the heterostructure is at a temperature of around 360 K and the Mn
3
Pt is close to the phase transition between a low-temperature non-collinear antiferromagnetic state and a high-temperature collinear antiferromagnetic state. The switching effect is due to piezoelectric strain transferred from the BaTiO
3
substrate to the Mn
3
Pt film by interfacial strain mediation.
The anomalous Hall effect has been observed in high-quality epitaxial thin films of non-collinear antiferromagnet Mn
3
Pt, and can be switched on and off using an electric field.
Journal Article
Electrically reversible cracks in an intermetallic film controlled by an electric field
by
Wong, A. T.
,
Liu, Z. Q.
,
Gludovatz, B.
in
639/301/1005/1007
,
639/301/1005/1008
,
Catastrophic events
2018
Cracks in solid-state materials are typically irreversible. Here we report electrically reversible opening and closing of nanoscale cracks in an intermetallic thin film grown on a ferroelectric substrate driven by a small electric field (~0.83 kV/cm). Accordingly, a nonvolatile colossal electroresistance on–off ratio of more than 10
8
is measured across the cracks in the intermetallic film at room temperature. Cracks are easily formed with low-frequency voltage cycling and remain stable when the device is operated at high frequency, which offers intriguing potential for next-generation high-frequency memory applications. Moreover, endurance testing demonstrates that the opening and closing of such cracks can reach over 10
7
cycles under 10-μs pulses, without catastrophic failure of the film.
Electric-field-induced cracks are generally detrimental to functionality of ferroelectric ceramics. Liu et al. use an intermetallic alloy and ferroelectric oxide junction to mediate the reversible formation of cracks at nanoscales, resulting in colossal electroresistance modulation for memory applications.
Journal Article
Nuclear loss of protein arginine N-methyltransferase 2 in breast carcinoma is associated with tumor grade and overexpression of cyclin D1 protein
2014
Human protein arginine
N
-methyltransferase 2 (PRMT2, HRMT1L1) is a protein that belongs to the arginine methyltransferase family, and it has diverse roles in transcriptional regulation through different mechanisms depending on its binding partners. In this study, we provide evidences for the negative effect of PRMT2 on breast cancer cell proliferation
in vitro
and
in vivo
. Morever, cyclin D1, one of the key modulators of cell cycle, was found to be downregulated by PRMT2, and PRMT2 was further shown to suppress the estrogen receptor α-binding affinity to the activator protein-1 (AP-1) site in
cyclin D1
promoter through indirect binding with AP-1 site, resulting in the inhibition of
cyclin D1
promoter activity in MCF-7 cells. Furthermore, a positive correlation between the expression of PRMT2 and cyclin D1 was confirmed in the breast cancer tissues by using tissue microarray assay. In addition, PRMT2 was found to show a high absent percentage in breast caner cell nuclei and the nuclear loss ratio of PRMT2 was demonstrated to positively correlate with cyclin D1 expression and the increasing tumor grade of invasive ductal carcinoma. Those results offer an essential insight into the effect of PRMT2 on breast carcinogenesis, and PRMT2 nuclear loss might be an important biological marker for the diagnosis of breast cancer.
Journal Article
A parameterization of low visibilities for hazy days in the North China Plain
2012
Visibility degradation is a pervasive and urgent environmental problem in China. The occurrence of low visibility events is frequent in the North China Plain, where the aerosol loading is quite high and aerosols are strongly hygroscopic. A parameterization of light extinction (Kex) for low visibilities on hazy days is proposed in this paper, based on visibility, relative humidity (RH), aerosol hygroscopic growth factors and particle number size distributions measured during the Haze in China (HaChi) Project. Observational results show that a high aerosol volume concentration is responsible for low visibility at RH <90%; while for RH >90%, decrease of visibility is mainly influenced by the increase of RH. The parameterization of Kex is developed on the basis of aerosol volume concentrations and RH, taking into accounts the sensitivity of visibility to the two factors and the availability of corresponding data. The extinction coefficients calculated with the parameterization schemes agree well with the directly measured values.
Journal Article
Worldwide Status of CCUS Technologies and Their Development and Challenges in China
by
Hou, Z.
,
Liu, H. J.
,
Were, P.
in
Air quality management
,
Carbon capture and storage
,
Carbon dioxide
2017
Carbon capture, utilization, and storage (CCUS) is a gas injection technology that enables the storage of CO2 underground. The aims are twofold, on one hand to reduce the emissions of CO2 into the atmosphere and on the other hand to increase oil/gas/heat recovery. Different types of CCUS technologies and related engineering projects have a long history of research and operation in the USA. However, in China they have a short development period ca. 10 years. Unlike CO2 capture and CO2-EOR technologies that are already operating on a commercial scale in China, research into other CCUS technologies is still in its infancy or at the pilot-scale. This paper first reviews the status and development of the different types of CCUS technologies and related engineering projects worldwide. Then it focuses on their developments in China in the last decade. The main research projects, international cooperation, and pilot-scale engineering projects in China are summarized and compared. Finally, the paper examines the challenges and prospects to be experienced through the industrialization of CCUS engineering projects in China. It can be concluded that the CCUS technologies have still large potential in China. It can only be unlocked by overcoming the technical and social challenges.
Journal Article
Response of rumen microbiota, and metabolic profiles of rumen fluid, liver and serum of goats to high-grain diets
by
Mao, S. Y.
,
Liu, J. H.
,
Liu, Y. J.
in
amino acid metabolism
,
amino acids
,
aminoacyl transfer RNA
2019
Feeding ruminants a high-grain (HG) diet is a widely used strategy to improve milk yield and cost efficiency. However, it may cause certain metabolic disorders. At present, information about the effects of HG diets on the systemic metabolic profile of goats and the correlation of such diets with rumen bacteria is limited. In the present study, goats were randomly divided into two groups: one was fed the hay diet (hay; n = 5), while the other was fed HG diets (HG; n = 5). On day 50, samples of rumen contents, peripheral blood serum and liver tissues were collected to determine the metabolic profiles in the rumen fluid, liver and serum and the microbial composition in rumen. The results revealed that HG diets reduced (P < 0.05) the community richness and diversity of rumen microbiota, with an increase in the Chao 1 and Shannon index and a decrease in the Simpson index. HG diets also altered the composition of rumen microbiota, with 30 genera affected (P < 0.05). Data on the metabolome showed that the metabolites in the rumen fluid, liver and serum were affected (variable importance projection > 1, P <0.05) by dietary treatment, with 47, 10 and 27 metabolites identified as differentially metabolites. Pathway analysis showed that the common metabolites in the shared key pathway (aminoacyl-transfer RNA biosynthesis) in the rumen fluid, liver and serum were glycine, lysine and valine. These findings suggested that HG diets changed the composition of the rumen microbiota and metabolites in the rumen fluid, liver and serum, mainly involved in amino acid metabolism. Our findings provide new insights into the understanding of diet-related systemic metabolism and the effects of HG diets on the overall health of goats.
Journal Article