Boron -Uptake Mechanisms and Boron Nutrition of Rice.

There are very few studies on B deficiency in rice (Oryza sativa L.). Reported critical values of B deficiency in rice are contradictory and mechanisms of B uptake by plant are not understood. Objectives of this study were to determine B effects on rice grown in hydroponics and soil; to determine critical values of B deficiency in rice tissues, hydroponic solution and soil; and to explore B-uptake mechanisms in both monocots (rice) and dicots (soybean (Glycine max L.)). Rice was grown to maturity in an acid Caddo silt loam at 0 and 1 kg B ha--1 in a greenhouse study, which provided the first report of B deficiency in rice grown on a soil from the USA. Boron increased B concentrations in new leaves, pollen vitality, and grain yields by 11%. Critical value of B deficiency in new rice leaves at tillering or booting is likely 6.0 +/- 1.0 mg B kg--1. A Ca/B ratio above 550 in rice leaves at booting would also indicate B deficiency. Retarded panicle development and delayed heading were observed at tillering and booting. Hydroponic studies indicated that B deficiency occurred when there was \u3c7.3 mg B kg --1 in new leaves and \u3c0.2 muM in solutions. Whitish and twisted new leaf tips occurred at ≤0.05 muM B, and pale bands 2--3 mm wide exhibited on leaves of moderately B-deficient plants. The membrane permeability coefficient of H3BO3 was determined to be 0.488 x 10--6 cm s--1 for rice roots and 1.81 x 10--1 cm s--1 for soybean roots. Estimating boron diffusion during the six-hour assay is a novel and accurate technique for determining the importance of diffusion, transpirational flow, and active uptake mechanisms. It was estimated that 59% of total B uptake for rice and 39% for soybean were due to active uptake for B-deficient plants. Significant effects were found from respiration inhibitors (0.05 mM DNP) on B uptake by B-deficient rice grown in solutions at four levels of B (0.2, 0.5, 2.5 and 10 muM) during a six-hour assay

Screening Functionalised Polymersomes Targeting Transcytosis Across Blood-Brain Barrier

The aims of this research project were to manufacture and characterise PDPA-based pH-sensitive functionalised polymersomes using a medium-high content screening method, suitable for CNS drug delivery. Angiopep-2 functionalised polymersome formulations have been found that are able to penetrate the blood-brain barrier (BBB) effectively in both in vitro models and in vivo. Using Transmission Electron Microscopy, Dynamic Light Scattering, FACS analysis, and 2D in vitro screening gave information on the physical and biological features of polymersomes based on their different chemistries, including size distribution, architecture, topology, cellular localisation, cellular uptake kinetic and immune response. The studies showed the possibility of controlling cellular internalization and cargo destinations by manipulating polymersome surface chemistry and specific ligand(s). The subsequent in vitro and in vivo studies built on these screening results. Using extensive Confocal Laser Microscopy and image analysis, Ang-POEGMA-PDPA polymersomes showed effective receptor-mediated transcytosis (RMT) in the 3D in vitro BBB model established, while the RVG- functionalised formulation did not. Further in vivo studies showed that the Ang-functionalised polymersomes were able to penetrate the mouse BBB via effective RMT. Moreover, primary cargo delivery studies showed successful IgG transport into brain by Angiopep-2-functionalised POEGMA-PDPA polymersomes. The results in this thesis can provide a useful platform for further examination of CNS delivery of polymersomes and their cargos

High Speed Optical Links Using CAP Modulation and Novel Equalisation Techniques

High speed optical links suffer from inter-symbol-interference (ISI) due to their limited bandwidth. Equalisation is typically used to mitigate ISI and therefore improve the link capacity. This dissertation explores novel equalisation techniques for carrierless amplitude and phase (CAP) modulation based optical communication systems including OM4 based and plastic optical fibre (POF) based links. An 850 nm VCSEL based OM4 link using CAP-16 scheme is studied. For the first time, the CAP equaliser, is proposed to mitigate both crosstalk channel interference (CCI) and ISI in the link at the receiver side. Performance comparisons are studied between the CAP-16 scheme using CAP equaliser and a conventional equaliser, pulse amplitude modulation (PAM-4) scheme, and discrete multitone (DMT) scheme. CAP based data transmission of 112 Gb/s is achieved over 150 m OM4 fibre with this novel equaliser, while the conventional equaliser can only support over 1 m OM4 fibre and fails to recover the signals at the same data rate. In addition, this novel equaliser provides a 1.2 dB and 1.7 dB improvement in receiver sensitivity over PAM-4 and DMT schemes, respectively, at 112 Gb/s over 100 m OM4 fibre. A novel pre-CAP-equaliser solving CCI at the transmitter side is also proposed. Data transmission of 56 Gb/s over 100 m OM4 fibre is reported experimentally with an improvement of 0.7 dB in receiver sensitivity compared to using the CAP equaliser at the receiver side. A simulation study shows a 2 dB improvement in receiver sensitivity at 112 Gb/s over 100 m OM4 fibre. Furthermore, an artificial neural network (ANN) equaliser in conjunction with the CAP equaliser structure is explored in a VCSEL based OM4 fibre link in order to further mitigate the nonlinear impairments. For 112 Gb/s data transmission over 100 m OM4 fibre, a 2.4 dB improvement of receiver sensitivity is achieved compared to the CAP equaliser. In addition to the electrical equalisers, a monolithically integrated silicon optical equaliser consisting of three taps is used for 50 Gb/s data transmission. After 10 km standard single mode fibre (SSMF), error free eye diagrams at the receiver are demonstrated. A μLED based POF link based on an APD receiver is also investigated with the CAP equaliser at the receiver side. Data transmission rates of 4 Gb/s over 25 m and 5 Gb/s over 10 m POF links are demonstrated with this equaliser while the conventional equaliser can only support 4 Gb/s over 10 m and fails to recover the signals for 5 Gb/s data transmission

Dreamland:

I was attracted by the interaction between dream and reality. Not long before I started my thesis, I read Freud’s book, The Interpretation of Dreams, and it quite interested me. In Freud’s theory, the complete personality is composed of id, ego and super-ego. The id is the set of coordinated instinctual trends; the super-ego plays the critical and moralizing role; and the ego is the organized, realistic part that mediates between the desires of the id and the super-ego. The super-ego can stop one from doing certain things that one’s id may want to do. These three parts dominate a human’s mental life, including dreaming. Dreams have the power of censorship, which occurs when the super-ego tries to suppress the id. Freud thought the essence of the dream is the fulfillment of wishes; wishes that come from people’s instinctive desires without disguise. However, not all wishes are reasonable and achievable. To pass the censor and fulfill unreasonable wishes in a dream, a human’s brain has to put on a disguise. This is why most dreamlands look absurd, but with deep exploration, one will find out the hint of those covered wishes. The relationship between dream and reality is similar to that of a mirror and reflection. In my work, I wanted to create an environment that would depict the interaction between dreams and reality. I wished to give viewers the experience of feeling the abstract definition of “dreamland,” instead of a specific view of a particular dreamland. I chose painting and installation work as the format to build the “Dreamland” environment because visual plays a big part in dreams and painting is the best and most straightforward way to access the visual sense. Installation work has rich expressive capacity and can be suitable for representing abstract ideas. I also saw installation work as one of the current most popular art forms, so I wanted to try it in my final school project

Remove Cosine Window from Correlation Filter-based Visual Trackers: When and How

Correlation filters (CFs) have been continuously advancing the state-of-the-art tracking performance and have been extensively studied in the recent few years. Most of the existing CF trackers adopt a cosine window to spatially reweight base image to alleviate boundary discontinuity. However, cosine window emphasizes more on the central region of base image and has the risk of contaminating negative training samples during model learning. On the other hand, spatial regularization deployed in many recent CF trackers plays a similar role as cosine window by enforcing spatial penalty on CF coefficients. Therefore, we in this paper investigate the feasibility to remove cosine window from CF trackers with spatial regularization. When simply removing cosine window, CF with spatial regularization still suffers from small degree of boundary discontinuity. To tackle this issue, binary and Gaussian shaped mask functions are further introduced for eliminating boundary discontinuity while reweighting the estimation error of each training sample, and can be incorporated with multiple CF trackers with spatial regularization. In comparison to the counterparts with cosine window, our methods are effective in handling boundary discontinuity and sample contamination, thereby benefiting tracking performance. Extensive experiments on three benchmarks show that our methods perform favorably against the state-of-the-art trackers using either handcrafted or deep CNN features. The code is publicly available at https://github.com/lifeng9472/Removing_cosine_window_from_CF_trackers.Comment: 13 pages, 7 figures, submitted to IEEE Transactions on Image Processin