Distribution of Camptotheca Decaisne: Endangered Status

Camptotheca Decaisne is endemic to southern China. Since 1934, C. acuminata has been widely introduced to many gardens and arboreta in North America, Asia, and Europe as living collections. Our national surveys in China between 1995 and 1998 indicated that the genus. Camptotheca spp. are severely endangered in native range. Our field surveys failed to locate any wild populations of C. acuminata although it is often cultivated as landscape trees in southern China. We could not identify any living trees of C. acuminata var. tenuifolia and var. rotundifolia. We estimated that there are approximately 500 mature trees of C. lowreyana in Guangdong and less than 50 wild mature trees of C. yunnanensis in Yunnan

Next Generation Graphene Photonics Enabled by Ultrafast Light-Matter Interactions and Machine Learning

Graphene was first experimentally studied in 2004, featuring an atomically-thin structure. Since then, many unique photonic and electrical properties of graphene and other 2D materials were reported. However, additional efforts are necessary to convert these findings in physics to successful industrial applications. This thesis presents works exploiting the picosecond-scale ultrafast light-matter interactions in graphene to meet the growing demands in IR sensing, 3D detection, and THz light source. We will start from graphene’s interactions with ultrafast lasers. The hot carrier generation, relaxation, and transport will be discussed in graphene and graphene heterostructures. We present a graphene phototransistor with decent near- and mid-infrared (IR) responsivity. Moreover, the detector’s responsivity is tunable with a gate voltage. The responsivity has different gate dependence under different illumination wavelengths. Based on the spectrally-resolved response, we adopt least square regression algorithms to extract the light source’s spectral information at near-infrared. We further perform first-principle photocurrent simulations and spectral reconstructions on defect-free ideal devices with optimized band structure. The results indicate the detector's potential as an ultra-compact on-chip spectrometer for multispectral imaging after further developments. Then we discuss how the graphene detector’s high transparency enables a novel 3D detection and imaging technology. Our graphene phototransistors absorb < 10% of light and give a 3 A/W photoresponse at 532 nm wavelength. The high transparency and sensitivity enable transparent photodetector arrays built on glass substrates, with over 85% of incident light power transmits through such an imager chip. We stack multiple transparent arrays at different focal depths in a camera system. The setup enables simultaneous light intensity (image) acquisition at different depths. We use artificial neural networks to process the image stack data into 3D position and configuration of the objects. For a proof-of-concept demonstration, we used the setup to achieve 3D ranging and tracking of a point source. The technical approach benefits from compactness, high speed, and decent power efficiency for real-time 3D tracking applications. Lastly, we explore the potential of graphene heterostructures as terahertz (THz) emitters and ultrafast photodetectors. The picosecond-scale light-matter interaction of graphene allows us to engineer its optical and electrical structures for THz field emission. We insert a graphene layer in the channel of a silicon photoconductive switch. The device works as a THz electromagnetic wave emitter under femtosecond laser pulse illumination. We use an on-chip pump-probe system to study the temporal and spatial behavior of the THz generation. Our device’s emission amplitude is 80 times larger than a graphene-free control group under identical device geometry and test conditions. Moreover, we also observe strong photocurrent generation below 0.5 ps verified by the photocurrent autocorrelation test. The responsivity is 800 times larger than that in the graphene-free control group. The substantial enhancements are attributed to the high mobility in graphene and the strong absorption in silicon. Gate dependence observations indicate vertical hot-carrier transfer from the silicon layer to the graphene layer, followed by efficient lateral charge separation inside graphene. The results open the gate for more research and development of graphene-based strong THz sources and sensitive ultrafast photodetectors. We conclude the works with strategies to convert graphene’s unique properties to practical and competitive applications. The strategies are extended to general nanodevice and nano-system development methodologies. Specifically, we propose the synergic design of nanodevices and machine learning algorithms as a feasible approach towards many new applications.PHDElectrical and Computer EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169683/1/dehui_1.pd

The Antitumor Effects of Plasma-Activated Saline on Muscle-Invasive Bladder Cancer Cells in Vitro and in Vivo Demonstrate Its Feasibility as a Potential Therapeutic Approach

Muscle-invasive bladder cancer (MIBC) is a fast-growing and aggressive malignant tumor in urinary system. Since chemotherapy and immunotherapy are only useable with a few MIBC patients, the clinical treatment of MIBC still faces challenges. Here, we examined the feasibility of plasma-activated saline (PAS) as a fledgling therapeutic strategy for MIBC treatment. Our data showed that plasma irradiation could generate a variety of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in saline. In vivo tests revealed that pericarcinomatous tissue injection with PAS was effective at preventing subcutaneous bladder tumor growth, with no side effects to the visceral organs after long-term administration, as well as having no obvious influence on the various biochemistry indices of the blood in mice. The in vitro studies indicated that adding 30% PAS in cell culture media causes oxidative damage to the bladder transitional cells T24 and J82 through enhancing the intracellular ROS level, and eventually induces cancer cells\u27 apoptosis by activating the ROS-mediated Fas/CD95 pathway. Therefore, for an intracavity tumor, these initial observations suggest that the soaking of the tumor tissue with PAS by intravesical perfusion may be a novel treatment option for bladder cancer

Printing surface charge as a new paradigm to program droplet transport

Directed, long-range and self-propelled transport of droplets on solid surfaces, especially on water repellent surfaces, is crucial for many applications from water harvesting to bio-analytical devices. One appealing strategy to achieve the preferential transport is to passively control the surface wetting gradients, topological or chemical, to break the asymmetric contact line and overcome the resistance force. Despite extensive progress, the directional droplet transport is limited to small transport velocity and short transport distance due to the fundamental trade-off: rapid transport of droplet demands a large wetting gradient, whereas long-range transport necessitates a relatively small wetting gradient. Here, we report a radically new strategy that resolves the bottleneck through the creation of an unexplored gradient in surface charge density (SCD). By leveraging on a facile droplet printing on superamphiphobic surfaces as well as the fundamental understanding of the mechanisms underpinning the creation of the preferential SCD, we demonstrate the self-propulsion of droplets with a record-high velocity over an ultra-long distance without the need for additional energy input. Such a Leidenfrost-like droplet transport, manifested at ambient condition, is also genetic, which can occur on a variety of substrates such as flexible and vertically placed surfaces. Moreover, distinct from conventional physical and chemical gradients, the new dimension of gradient in SCD can be programmed in a rewritable fashion. We envision that our work enriches and extends our capability in the manipulation of droplet transport and would find numerous potential applications otherwise impossible.Comment: 11 pages, 4 figure

Contribution of Gray and White Matter Abnormalities to Cognitive Impairment in Multiple Sclerosis

Patients with multiple sclerosis (MS) commonly exhibit cognitive impairments (CI). However, the neural mechanisms underlying CI remain unclear. The current study applied diffusion tensor imaging (DTI) and voxel-based morphometric (VBM) magnetic resonance imaging (MRI) techniques to evaluate differences in white matter (WM) integrity and gray matter (GM) volume between MS patients with CI and MS patients with cognitive preservation (CP). Neuropsychological assessment and MRI were obtained from 39 relapsing-remitting MS (RRMS) patients and 29 healthy controls (HCs). Patients were classified as CI or CP according to cognitive ability, and demographic characteristics and MRI images were compared. Compared with HCs, MS patients exhibited widespread damage in WM integrity, and GM loss in several regions. Compared with CP patients, CI patients exhibited more extensive WM impairments, particularly in the corpus callosum, cerebellar peduncle, corona radiata, optic radiation, superior longitudinal fasciculus, anterior limb of the internal capsule, and cingulate, as well as decreased GM volume in the bilateral caudate, left insula and right temporal lobe. MS patients with CI exhibited more significant structural abnormalities than those with CP. Widespread impairments of WM integrity and selective GM atrophy both appear to be associated with impaired cognition in RRMS

Suppressing miRNA-15a/-16 expression by interleukin-6 enhances drug-resistance in myeloma cells

The bone marrow microenvironment facilitates the survival, differentiation, and proliferation of myeloma (MM) cells. This study identified that microRNA-15a and -16 expressions tightly correlated with proliferation and drug sensitivity of MM cells. miRNA-15a/-16 expression in MM cells was significantly increased after treatment with cytotoxic agents. The interaction of bone marrow stromal cells (BMSC) with MM cells resulted in decreased miRNA-15a/-16 expression and promoted the survival of the MM cells. Interleukin-6 (IL-6) produced by BMSCs suppressed the expression of miRNA-15a and 16 in a time- and dose- dependent pattern, with the suppression on miRNA-15a being more significant than on miRNA-16. miRNA-15a-transfected MM cells were found to be arrested in G1/S checkpoint, and the transfected MM cells had decreased growth and survival. In conclusion, our data suggest that via suppressing miRNA-15a and -16 expressions, IL-6 secreted by BMSCs promotes drug-resistance in myeloma cells

Effects of Plasma-Activated Water on Skin Wound Healing in Mice

Cold atmospheric plasma (CAP) has been widely used in biomedicine during the last two decades. While direct plasma treatment has been reported to promote wound healing, its application can be uneven and inconvenient. In this study, we first activated water with a portable dielectric barrier discharge plasma device and evaluated the inactivation effect of plasma-activated water (PAW) on several kinds of bacteria that commonly infect wounds. The results show that PAW can effectively inactivate these bacteria. Then, we activated tap water and examined the efficacy of PAW on wound healing in a mouse model of full-thickness skin wounds. We found that wound healing in mice treated with PAW was significantly faster compared with the control group. Histological analysis of the skin tissue of mice wounds showed a significant reduction in the number of inflammatory cells in the PAW treatment group. To identify the possible mechanism by which PAW promotes wound healing, we analyzed changes in the profiles of wound bacteria after PAW treatment. The results show that PAW can significantly reduce the abundance of wound bacteria in the treatment group. The results of biochemical blood tests and histological analysis of major internal organs in the mice show that PAW had no obvious side effects. Taken together, these results indicate that PAW may be a new and effective method for promoting wound healing without side effects

QTL mapping and genomic prediction of resistance to wheat head blight caused by Fusarium verticillioides

Fusarium head blight (FHB), is one of the destructive fugue diseases of wheat worldwide caused by the Fusarium verticillioides (F.v). In this study, a population consisting of 262 recombinant inbred lines (RILs) derived from Zhongmai 578 and Jimai 22 was used to map Quantitative Trait Locus (QTL) for FHB resistance, with the genotype data using the wheat 50 K single nucleotide polymorphism (SNP) array. The percentage of symptomatic spikelet (PSS) and the weighted average of PSS (PSSW) were collected for each RIL to represent their resistance to wheat head blight caused by F.v. In total, 22 QTL associated with FHB resistance were identified on chromosomes 1D, 2B, 3B, 4A, 5D, 7A, 7B, and 7D, respectively, from which 10 and 12 QTL were detected from PSS and PSSW respectively, explaining 3.82%–10.57% of the phenotypic variances using the inclusive composite interval mapping method. One novel QTL, Qfhb. haust-4A.1, was identified, explaining 10.56% of the phenotypic variation. One stable QTL, Qfhb. haust-1D.1 was detected on chromosome 1D across multiple environments explaining 4.39%–5.70% of the phenotypic variation. Forty-seven candidate genes related to disease resistance were found in the interval of Qfhb. haust-1D.1 and Qfhb. haust-4A.1. Genomic prediction accuracies were estimated from the five-fold cross-validation scheme ranging from 0.34 to 0.40 for PSS, and from 0.34 to 0.39 for PSSW in in-vivo inoculation treatment. This study provided new insight into the genetic analysis of resistance to wheat head blight caused by F.v, and genomic selection (GS) as a potential approach for improving the resistance of wheat head blight

NO2- and NO3- Enhance Cold Atmospheric Plasma Induced Cancer Cell Death by Generation of ONOO-

Cold atmospheric plasma (CAP) is a rapidly developed technology that has been widely applied in biomedicine especially in cancer treatment. Due to the generation of various active species in plasma, CAP could induce various tumor cells death and showed a promising potential in cancer therapy. To enhance the biological effects of gas plasma, changing the discharging parameters is the most commonly used method, yet increasing discharging power will lead to a higher possibility of simultaneously damage surrounding tissues. In this study, by adding nontoxic concentration of additional nitrite and nitrate in the medium, we found that anti-tumor effect of CAP treatment was enhanced in the same discharging parameters. By microplate reader and cell flow cytometer we measured several extracellular and intracellular RONS and found that ONOO- was mostly correlated with the enhanced cancer cell killing effect. We proposed that more nitrogen supplies such as nitrite and nitrate could increase the production of RNS especially ONOO- and resulted in a better killing effect to cancer cells. Our results provided a new strategy to enhance the antitumor effect by plasma jet treatment without changing the discharging parameters. © 2018 Author(s)