67 research outputs found
Processes of intraseasonal snow cover variations over the eastern China during boreal winter
This study reveals that the dominant time scale of intraseasonal snow cover variation over the eastern China is within 30ādays by using the latest satellite snow cover data from the moderate resolution imaging spectroradiometer (MODIS)/Terra product. The leading empirical orthogonal function (EOF) mode of 10ā30āday snow cover variation during boreal winter from 2004 to 2018 over the eastern China has two centers: northwest part of the eastern China and north of the Yangtze River. Composite analysis based on 25 snow events identified from normalized leading principal time series (PC1) indicates that the southeastward intrusion of surface anticyclonic anomalies and accompanying low temperature anomalies provide the temperature condition for snow events. Negative Arctic Oscillation induces midālatitude wave train and leads to the development of surface anticyclonic anomalies and upperālevel cyclonic anomalies over East Asia. The cyclonic anomalies induce ascending motion and anomalous convergence of water vapor fluxes over the eastern China, which supplies moisture for snowfall.(a) Time evolution of composite NAO index (pink curve), AO index (blue curve), regional mean surface air temperature anomalies (Ā°C) (black curve) and snow cover anomalies (%) (red curve) in the region of 20ā40Ā°N, 105ā120Ā°E. (b) Time evolution of composite anomalies of regional mean snow cover tendency (%/day) (black curve), vertical velocity (Pa/s) (blue curve), and divergence of water vapor flux integral from 1,000 to 100āhPa (*10ā6 kg/(m2*s)) (pink curve) in the region of 20ā40Ā°N, 105ā120Ā°E. Dots on the curves indicate anomalies significant at the 95% confidence level.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149343/1/asl2901_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149343/2/asl2901.pd
Plant Phenotyping on Mobile Devices
Plants phenotyping is a fast and non-destructive method to obtain the physiological features of plants, compared with the expensive and time costing chemical analysis with plant sampling. Through plant phenotyping, scientists and farmers can tell plant health status more accurately compared to visual inspection, thus avoid the waste in time and resources and even to predict the productivity. However, the size and price of current plant phenotyping equipment restrict them from being widely applied at a farmerās household level. Everyday field operation is barely achieved because of the availability of easy-to-carry and cost-effective equipment such as hyper-spectrum cameras, infrared cameras and thermal cameras. A plant phenotyping tool on mobile devices will make plant phenotyping technology more accessible to ordinary farmers and researchers. This application incorporates the use of physical optics, plant science models, and image processing ability of smartphones. With our special optical design, multispectral instead of RGB (red, green and blue) images can be obtained from the smartphones with fairly low cost. Through quick image processing on the smartphones, the APP will provide accurate plant physiological features predictions such as water, chlorophyll, and nitrogen. The sophisticated prediction models are applied which are provided by the Purdueās plant phenotyping team. Once widely adopted, the information collected by the smartphones with the developed APP will be sent back to Purdueās plant health big-data database. The feedback will not only allow us to improve our models, but also provide farmers and agricultural researchers easy access to real-time crop plant health data
Fabrication of three-dimensional microdisk resonators in calcium fluoride by femtosecond laser micromachining
We report on fabrication of on-chip calcium fluoride (CaF2) microdisk
resonators using water-assisted femtosecond laser micromachining. Focused ion
beam (FIB) milling is used to create ultra-smooth sidewalls. The quality
(Q)-factors of the fabricated microresonators are measured to be 4.2x10^4 at
wavelengths near 1550 nm. The Q factor is mainly limited by the scattering from
the bottom surface of the disk whose roughness remains high due to the
femtosecond laser micromachining process. This technique facilitates formation
of on-chip microresonators on various kinds of bulk crystalline materials,
which can benefit a wide range of applications such as nonlinear optics,
quantum optics, and chip-level integration of photonic devices.Comment: 7 pages, 3 figure
On-chip tuning of the resonant wavelength in a high-Q microresonator integrated with a microheater
We report on fabrication of a microtoroid resonator of high-quality (high-Q)
factor integrated with an on-chip microheater. Both the microresonator and
microheater are fabricated using femtosecond laser three-dimensional (3D)
micromachining. The microheater, which is located about 200 micron away from
the microresonator, has a footprint size of 200 micron by 400 micron. Tuning of
the resonant wavelength in the microresonator has been achieved by varying the
voltage applied on the microheater. The drifting of the resonant wavelength
shows a linear dependence on the square of the voltage applied on the
microheater. We found that the response time of the microresonator is less than
10 secs which is significantly shorter than the time required for reaching a
thermal equilibrium on conventional heating instruments such as an external
electric heater
Fabrication of an integrated high-quality-factor (high-Q) optofluidic sensor by femtosecond laser micromachining
We report on fabrication of a microtoroid resonator of a high-quality factor
(i. e., Q-factor of ~3.24x10^6 measured under the critical coupling condition)
integrated in a microfluidic channel using femtosecond laser three-dimensional
(3D) micromachining. Coupling of light into and out of the microresonator has
been realized with a fiber taper that is reliably assembled with the
microtoroid. The assembly of the fiber to the microtoroid is achieved by
welding the fiber taper onto the sidewall of the microtoroid using CO_2 laser
irradiation. The integrated microresonator maintains a high Q-factor of
3.21x10^5 as measured in air, which should still be sufficient for many sensing
applications. We test the functionality of the integrated optofluidic sensor by
performing bulk refractive index sensing of purified water doped with tiny
amount of salt. It is shown that a detection limit of ~1.2x10^-4 refractive
index unit can be achieved. Our result showcases the capability of integration
of high-Q microresonators with complex microfluidic systems using femtosecond
laser 3D micromachining.Comment: 6 pages, 5 figures. arXiv admin note: text overlap with
arXiv:1402.135
Raptor wing morphing with flight speed
In gliding flight, birds morph their wings and tails to control their flight trajectory and speed. Using high-resolution videogrammetry, we reconstructed accurate and detailed three-dimensional geometries of gliding flights for three raptors (barn owl, Tyto alba; tawny owl, Strix aluco, and goshawk, Accipiter gentilis). Wing shapes were highly repeatable and shoulder actuation was a key component of reconfiguring the overall planform and controlling angle of attack. The three birds shared common spanwise patterns of wing twist, an inverse relationship between twist and peak camber, and held their wings depressed below their shoulder in an anhedral configuration. With increased speed, all three birds tended to reduce camber throughout the wing, and their wings bent in a saddle-shape pattern. A number of morphing features suggest that the coordinated movements of the wing and tail support efficient flight, and that the tail may act to modulate wing camber through indirect aeroelastic control
The host transcriptome change involved in the inhibitory effect of exogenous interferon-Ī³ on Getah virus replication
IntroductionGetah virus (GETV) has become a growing potential threat to the global livestock industry and public health. However, little is known about the viral pathogenesis and immune escape mechanisms, leading to ineffective control measures.MethodsIn this study, the antiviral activity of exogenous interferons (IFNs) was assessed by using western blotting (WB), real-time quantitative PCR (RT-qPCR) and indirect immunofluorescence assay (IFA). The comparative transcriptomics among mock- and GETV-infected (MOI = 0.1) ST cells with or without IFN-Ī³ was performed by RNA-seq, and then the transcriptome profiling of GETV-infected ST cells and key pathways and putative factors involved in inhibitory effect of IFN-Ī³ on GETV replication were analyzed by bioinformatics methods and RT-qPCR.ResultsThe results showed that treatment with IFN-Ī³ could suppress GETV replication, and the inhibitory effect lasted for at least 48 h, while the exogenous IFN-Ī±/Ļ and IFN-Ī»3 treatments failed to inhibit the viral infection and early replication in vitro. Furthermore, the blueprint of virus-host interaction was plotted by RNA-seq and RT-qPCR, showing systemic activation of inflammatory, apoptotic, and antiviral pathways in response to GETV infection, indicating viral hijacking and inhibition of innate host immunity such as IFN-I/III responses. Last and most importantly, activation of the JAK-STAT signaling pathway and complement and coagulation cascades may be a primary driver for IFN-Ī³-mediated inhibition of GETV replication.DiscussionThese findings revealed that GETV possessed the capability of viral immune escape and indicated that IFN-Ī³ aided in the prevention and control of GETV, implying the potential molecular mechanism of suppression of GETV by IFN-Ī³, all of which warrant emphasis or further clarification
Plin4-Dependent Lipid Droplets Hamper Neuronal Mitophagy in the MPTP/p-Induced Mouse Model of Parkinsonās Disease
Epidemiological studies have shown that both lipid metabolism disorder and mitochondrial dysfunction are correlated with the pathogenesis of neurodegenerative diseases (NDDs), including Parkinsonās disease (PD). Emerging evidence suggests that deposition of intracellular lipid droplets (LDs) participates in lipotoxicity and precedes neurodegeneration. Perilipin family members were recognized to facilitate LD movement and cellular signaling interactions. However, the direct interaction between Perilipin-regulated LD deposition and mitochondrial dysfunction in dopaminergic (DA) neurons remains obscure. Here, we demonstrate a novel type of lipid dysregulation involved in PD progression as evidenced by upregulated expression of Plin4 (a coating protein and regulator of LDs), and increased intracellular LD deposition that correlated with the loss of TH-ir (Tyrosine hydroxylase-immunoreactive) neurons in the MPTP/p-induced PD model mouse mesencephalon. Further, in vitro experiments showed that inhibition of LD storage by downregulating Plin4 promoted survival of SH-SY5Y cells. Mechanistically, reduced LD storage restored autophagy, leading to alleviation of mitochondrial damage, which in turn promoted cell survival. Moreover, the parkin-poly-Ub-p62 pathway was involved in this Plin4/LD-induced inhibition of mitophagy. These findings were further confirmed in primary cultures of DA-nergic neurons, in which autophagy inhibitor treatment significantly countermanded the ameliorations conferred by Plin4 silencing. Collectively, these experiments demonstrate that a dysfunctional Plin4/LD/mitophagy axis is involved in PD pathology and suggest Plin4-LDs as a potential biomarker as well as therapeutic strategy for PD
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