Soft probes for bio-electrochemical imaging

The aim of bioimaging is to visualize properties and processes of living objects or biological samples and extracts image-related information for revealing important physical structures or map the distribution of specific biomolecules in tissues for clinical purposes. However, current bioimaging methods which mainly rely on the optical detection methods can suffer from optical interferences and thus bias the imaging results. Bio-electrochemical imaging with micrometer resolution represents a promising alternative tool since electrochemical signals, e.g. faradaic currents, depend exclusively on the redox reactions occurring at the sample surface and a sensing probe. Scanning electrochemical microscopy (SECM) is a scanning probe technique that is composed of a micro- or nanoelectrode that can be positioned or scanned in close proximity to an interface. Faradaic current signals can be recorded due to the flux of redox active species between the sample and an amperometric SECM probe. SECM can be used to image the topography and reactivity of biological specimens for mapping localized biochemical activity. Although SECM has been applied to different biological systems, SECM studies of tissues are still under exploration. The reason is due to the shape and high roughness of such real samples and requires overcoming major drawbacks in conventional SECM instrumentation when scanning large, i.e. square centimeter sized areas with irregular surface keeping a constant working distance. This thesis aims to develop various reliable SECM bioimaging techniques for the study of the antioxidant defense system of fruit peels, distribution of biomarkers and nanomaterials in thin and thick animal samples, as well as human melanoma. Particularly the last is of major importance, because melanoma is the most lethal form of skin cancer striking thousands of people around the world. The survival rate depends on the stage of the cancer when it is diagnosed. Therefore, reliable methodologies for early diagnosis and unequivocal identification of cancer stages are of high relevance. One of the well-known melanoma biomarkers is « tyrosinase » which is the key enzyme involved in the biosynthesis of melanin and fruit maturation. Different tyrosinase SECM detection strategies were developed for the analysis of the spatial distribution of tyrosinase in melanoma as well as in banana samples. It demonstrated in this thesis that that SECM could improve the diagnosis and understanding of different melanoma stages based on highly resolved maps of the tyrosinase distribution while being immune against optical interferences, e.g. from the presence of melanin in the skin samples. Spider probe composed of eight independent microelectrodes developed in this thesis allowed the large area scanning over thin and thick animal tissues in contact mode. The redox active proteins inside the entire mouse heart was imaged for the first time by spider probe. In addition, the distributions of injected conductive graphene nanoribbons (GONRs) for drug delivery were studied by Soft-Probe-SECM. Through the mapping of feedback mode currents over conductive GONRs, the GONRs were found concentrated inside lobules, which are hexagonal microstructures in the liver. Finally, this thesis describes a non-invasive electrochemical strategy for mapping the antioxidant (AO) activity of apple peels using Soft-Probe-SECM. The global AO activity in the apple peel including lenticels and regions with artifi

EFFECT OF DIFFERENT RUNNING SPEED ON VERTICAL OSCILLATION AND STRIDE

The main purpose of this study was to investigate the effect of different running speed (3.5±O.3 and 4.9±O.2 m/si on vertical oscillation of the center of gravity and stride. Ten male elite running players served as subjects. A camera (60Hz) was to collect the parameters during running. From this research, the t-Test is used to analyze the parameters of the kinematics in different running speed. Results indicated that different running speed would not affect the vertical oscillation of human body center of gravity. In addition, a significant difference (p< .05) was found in the same speed of different step, but no significance was found in different running speed of the same step. The duration of the stance phase in lower speed for about 38.34% of the stride and the swing phase for 61.66%, in higher speed for about 32.11 % and 67.89%

Mapping the antioxidant activity of apple peels with soft probe scanning electrochemical microscopy

We present a non-invasive electrochemical strategy for mapping the antioxidant (AO) activity of apple peels, which counterbalances oxidative stress caused by various external effectors. Soft carbon microelectrodes were used for soft probe scanning electrochemical microscopy (SECM) enabling the gentle and scratch-free in contact mode scanning of the rough and delicate apple peels in an electrolyte solution. The SECM feedback mode was applied using ferrocene methanol (FcMeOH) as redox mediator that gets electrochemically oxidized at the soft probe and diffuses towards the apple peel where it gets regenerated by certain AOs leading to a redox mediator recycling and increased current signal. The global AO activity in the apple peel including lenticels and regions with artificially degraded AOs were mapped using the soft microelectrodes. Finally, in an apple cross-section the higher and homogeneous AO concentration in the peel with a heterogeneously decaying AO gradient towards the apple inward was visualized, demonstrating the adequate micrometer resolution of the SECM probe and the possibility to get information of the interior AO activity of the apple

Metronidazole-Induced Irreversible Optic Neuropathy

Metronidazole-induced optic neuropathy is a rare complication. Most patients have excellent visual recovery. In this study, we report a patient who presented with a sudden onset of severe visual loss after a 1-week course of metronidazole. Myelitis developed simultaneously. The vision and the accompanying neurological deficiency of the patient did not improve even after metronidazole was discontinued immediately and various treatments were given

Deterioration Estimation of Reinforced Concrete Building Structures Using Material Testing Data Base

This study aims to investigate the material factors that affect the degree of deterioration of reinforced concrete structures and develop an integrating evaluation model. Also, the durability indices were generated using the analytic hierarchy process for the overall durability assessment of structures, which corresponded to the durability grades referred as the maintenance, reinforcement, or demolishment. The status of concrete includes compressive strength, resistance coefficient, concrete cracks, honeycomb and spalling. And the reinforcement status includes corrosion potential, corrosion current, chloride ion content, neutralization depth and protective layer thickness. Durability indicators were determined through the findings on the structural inspection process of reinforced concrete structures and the evaluation methods related to materials testing and industry standards. Case studies were also presented to illustrate the methodology of the assessment system. The durability methodology can be summarized as the comprehensive evaluation methods considering the earthquake potential factors, structural factors, environmental factors, and material deterioration factors

3-D neurohistology of transparent tongue in health and injury with optical clearing

Tongue receives extensive innervation to perform taste, sensory, and motor functions. Details of the tongue neuroanatomy and its plasticity in response to injury offer insights to investigate tongue neurophysiology and pathophysiology. However, due to the dispersed nature of the neural network, standard histology cannot provide a global view of the innervation. We prepared transparent mouse tongue by optical clearing to reveal the spatial features of the tongue innervation and its remodeling in injury. Immunostaining of neuronal markers, including PGP9.5 (pan-neuronal marker), calcitonin gene-related peptide (sensory nerves), tyrosine hydroxylase (sympathetic nerves), and vesicular acetylcholine transporter (cholinergic parasympathetic nerves and neuromuscular junctions), was combined with vessel painting and nuclear staining to label the tissue network and architecture. The tongue specimens were immersed in the optical-clearing solution to facilitate photon penetration for 3-dimensiontal (3-D) confocal microscopy. Taking advantage of the transparent tissue, we simultaneously revealed the tongue microstructure and innervation with subcellular-level resolution. 3-D projection of the papillary neurovascular complex and taste bud innervation was used to demonstrate the spatial features of tongue mucosa and the panoramic imaging approach. In the tongue injury induced by 4-nitroquinoline 1-oxide administration in the drinking water, we observed neural tissue remodeling in response to the changes of mucosal and muscular structures. Neural networks and the neuromuscular junctions were both found rearranged at the peri-lesional region, suggesting the nerve-lesion interactions in response to injury. Overall, this new tongue histological approach provides a useful tool for 3-D imaging of neural tissues to better characterize their roles with the mucosal and muscular components in health and disease

Neural Free-Viewpoint Relighting for Glossy Indirect Illumination

Precomputed Radiance Transfer (PRT) remains an attractive solution for real-time rendering of complex light transport effects such as glossy global illumination. After precomputation, we can relight the scene with new environment maps while changing viewpoint in real-time. However, practical PRT methods are usually limited to low-frequency spherical harmonic lighting. All-frequency techniques using wavelets are promising but have so far had little practical impact. The curse of dimensionality and much higher data requirements have typically limited them to relighting with fixed view or only direct lighting with triple product integrals. In this paper, we demonstrate a hybrid neural-wavelet PRT solution to high-frequency indirect illumination, including glossy reflection, for relighting with changing view. Specifically, we seek to represent the light transport function in the Haar wavelet basis. For global illumination, we learn the wavelet transport using a small multi-layer perceptron (MLP) applied to a feature field as a function of spatial location and wavelet index, with reflected direction and material parameters being other MLP inputs. We optimize/learn the feature field (compactly represented by a tensor decomposition) and MLP parameters from multiple images of the scene under different lighting and viewing conditions. We demonstrate real-time (512 x 512 at 24 FPS, 800 x 600 at 13 FPS) precomputed rendering of challenging scenes involving view-dependent reflections and even caustics.Comment: 13 pages, 9 figures, to appear in cgf proceedings of egsr 202