Imaging Three-Dimensional Single Molecule Dynamics in its Cellular Context

Three-dimensional single molecule microscopy enables the study of dynamic processes in living cells at the level of individual molecules. Multifocal plane microscopy (MUM) is an example of such a modality and has been shown to be capable of capturing the rapid subcellular trafficking of single molecules in thick samples by simultaneously imaging distinct focal planes within the sample. Regardless of the specific modality, however, the obtained 3D trajectories of single molecules often do not fully reveal the biological significance of the observed dynamics. This is because the missing cellular context is often also needed in order to properly understand the events observed at the molecular level. We introduce the remote focusing-MUM (rMUM) modality, which enables 3D single molecule imaging with the simultaneous z-stack imaging of the surrounding cellular structures. Using rMUM, we demonstrate the 3D tracking of prostate-specific membrane antigen (PSMA) with a PSMA-specific antibody in a prostate cancer cell. PSMA is an important biomarker for prostate cancer cells. As such, it is a common target for antibody-based therapies. For example, of particular interest is the use of PSMA-specific antibodies that are conjugated with a toxin that kills prostate cancer cells. We analyze here the pathways of PSMA-specific antibodies, from prior to their first binding to PSMA at the plasma membrane to their arrival at, and continued movement in, sorting endosomes. By making possible the observation of single molecule dynamics within the relevant cellular context, rMUM allows, in our current application, the identification and analysis of different stages of the PSMA-specific antibody trafficking pathway

An Examination of the Relative Significance of Convergence & Divergence in Employment of FLA & SLA Concepts: A Critical Literature Review

This paper critically examines the major studies regarding both first (FLA) and second (SLA) language acquisition. In particular, the key similarities and differences between FLA and SLA are noted and described with regard to their relative significance. In doing so, the primary texts were analyzed in terms of psychological factors, cognitive processes, Critical Period Hypothesis, and Universal Grammar. Findings indicate that the processes of first and second language acquisition are sufficiently different from one another whilst also maintaining a distinct level of interconnectivity; notably with regards to the effect of the native language on the learning of the target language, which can be influenced by processes connected to Universal Grammar. (Abstract translated from Korean

On the Applications of Computer-Assisted Language Learning in a Military English Context

This paper critically reviews the pedagogical benefits and obstacles to applying CALL to military English learning in terms of the theories associated with CALL. The obstacles that hinder effective CALL practice in military settings can be attributable to a) a long-held behavioristic tradition for language learning such as rote memorization and repetitive drilling; b) the antithesis of traditional military sentiment against the shift of learning responsibility from the military to individuals; and c) military instructors who may be incapable of implementing effective CALL practice because of their own preconceptions, backgrounds and established skill sets. However, properly implemented CALL not only prepares learners linguistically and culturally for participating in multinational military operations, but also provides learners with peer support opportunities where they can cooperate with their peers to achieve more than what they are capable of and enhance their interpersonal communication required in the military. CALL also benefits learners by enabling them to monitor their progress and promoting critical thinking.<br/

III-V Nanostructures for Photovoltaics Applications

The concept of introducing an intermediate band to overcome the efficiency limit of single-bandgap solar cells was proposed by Luque and Martí in 1997. It is predicted that utilising the intermediate band for multi-photon absorption can significantly improve the photocurrent generation without accompanying output voltage loss. Amongst several approaches to develop an intermediate band solar cell, quantum dots have drawn much attention as intermediate band due to their three-dimensional quantum confinement and bandgap tunability. However, despite the effort expended so far, there still remains several major challenges that prevent the successful implementation of quantum dot intermediate band solar cells. The work reported in this thesis aims to provide solutions to the main challenges in implementing high-efficiency quantum dot solar cells. The work involves the design, epitaxial growth by molecular beam epitaxy, device processing, and characterisation of QDSCs. This thesis first investigates the influence of direct Si doping on InAs/GaAs quantum dot solar cells with AlAs cap layers. Si doping in QDs leads to state filling of the intermediate band, which is one of the key requirements for a high-efficiency intermediate band solar cell. Moreover, the introduction of moderate amount of Si dopants leads to passivation of defect states, and hence prolongs the carrier lifetime and increases the open-circuit voltage. Secondly, type-II InAs/GaAsSb quantum dot solar cells are studied. Increased photocurrent contribution from the quantum dot region is observed due to the prolonged carrier lifetime associated with the type-II band alignment. Lastly, different types and positions of quantum dot doping methods are investigated. The photoluminescence spectra indicate that using delta or modulation doping in quantum dots can reduce the degradation of crystal quality, and hence decrease the number of non-radiative recombination centres, when compared with using direct doping

Attentive Illumination Decomposition Model for Multi-Illuminant White Balancing

White balance (WB) algorithms in many commercial cameras assume single and uniform illumination, leading to undesirable results when multiple lighting sources with different chromaticities exist in the scene. Prior research on multi-illuminant WB typically predicts illumination at the pixel level without fully grasping the scene's actual lighting conditions, including the number and color of light sources. This often results in unnatural outcomes lacking in overall consistency. To handle this problem, we present a deep white balancing model that leverages the slot attention, where each slot is in charge of representing individual illuminants. This design enables the model to generate chromaticities and weight maps for individual illuminants, which are then fused to compose the final illumination map. Furthermore, we propose the centroid-matching loss, which regulates the activation of each slot based on the color range, thereby enhancing the model to separate illumination more effectively. Our method achieves the state-of-the-art performance on both single- and multi-illuminant WB benchmarks, and also offers additional information such as the number of illuminants in the scene and their chromaticity. This capability allows for illumination editing, an application not feasible with prior methods.Comment: CVPR 202

MarioNETte: Few-shot Face Reenactment Preserving Identity of Unseen Targets

When there is a mismatch between the target identity and the driver identity, face reenactment suffers severe degradation in the quality of the result, especially in a few-shot setting. The identity preservation problem, where the model loses the detailed information of the target leading to a defective output, is the most common failure mode. The problem has several potential sources such as the identity of the driver leaking due to the identity mismatch, or dealing with unseen large poses. To overcome such problems, we introduce components that address the mentioned problem: image attention block, target feature alignment, and landmark transformer. Through attending and warping the relevant features, the proposed architecture, called MarioNETte, produces high-quality reenactments of unseen identities in a few-shot setting. In addition, the landmark transformer dramatically alleviates the identity preservation problem by isolating the expression geometry through landmark disentanglement. Comprehensive experiments are performed to verify that the proposed framework can generate highly realistic faces, outperforming all other baselines, even under a significant mismatch of facial characteristics between the target and the driver.Comment: In AAAI 202

Self-Calibrating, Fully Differentiable NLOS Inverse Rendering

Existing time-resolved non-line-of-sight (NLOS) imaging methods reconstruct hidden scenes by inverting the optical paths of indirect illumination measured at visible relay surfaces. These methods are prone to reconstruction artifacts due to inversion ambiguities and capture noise, which are typically mitigated through the manual selection of filtering functions and parameters. We introduce a fully-differentiable end-to-end NLOS inverse rendering pipeline that self-calibrates the imaging parameters during the reconstruction of hidden scenes, using as input only the measured illumination while working both in the time and frequency domains. Our pipeline extracts a geometric representation of the hidden scene from NLOS volumetric intensities and estimates the time-resolved illumination at the relay wall produced by such geometric information using differentiable transient rendering. We then use gradient descent to optimize imaging parameters by minimizing the error between our simulated time-resolved illumination and the measured illumination. Our end-to-end differentiable pipeline couples diffraction-based volumetric NLOS reconstruction with path-space light transport and a simple ray marching technique to extract detailed, dense sets of surface points and normals of hidden scenes. We demonstrate the robustness of our method to consistently reconstruct geometry and albedo, even under significant noise levels