Gravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) technologies. It operates at a low pressure by gravity, requiring a minimal energy. Thus, it exhibits a great potential for a decentralized system, conducting household in developing and transition countries. Biofouling is a universal problem in almost all membrane filtration applications, leading to the decrease in flux or the increase in transmembrane pressure depending on different operation mode. Air scoring or regular membrane cleaning has been utilized for fouling mitigation, which requires increased energy consumption as well as complicated operations. Besides, repeating cleaning will trigger the deterioration of membranes and shorten their lifetime, elevating cost expenditures accordingly. In this way, GDM filtration stands out from conventional MBR technologies in a long-term operation with relative stable flux, which has been observed in many studies. The objective of this study was to monitor the biofilm development on a flat sheet membrane submerged in a GDM reactor with constant gravitational pressure. Morphology of biofilm layer in a fixed position was acquired by an in-situ and on-line OCT (optical coherence tomography) scanning at regular intervals for both visual investigation and structure analysis. The calculated thickness and roughness were compared to the variation of flux, fouling resistance and permeate quality, showing expected consistency. At the end of experiment, the morphology of entire membrane surface was scanned and recorded by OCT. Membrane autopsy was carried out for biofilm composition analysis by total organic carbon (TOC) and liquid chromatography with organic carbon detection (LC-OCD). In addition, biomass concentration was obtained by flow cytometer and adenosine tri-phosphate (ATP) method. The data of biofilm components indicated a homogeneous biofilm structure formed after a long-term running of the GDM system, based on the morphology observation by OCT images. The superiority of GDM in both flux maintaining and long-term operation with production of high quality effluent was demonstrated, as well as the suitability of OCT for biofouling monitoring was emphasized.

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第13260号 / 論医博第2178号 / 新制||医||1037(附属図書館) / (主査)教授 溝脇 尚志, 教授 大森 孝一, 教授 富樫 かおり / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DFAM

Das Ziel der vorliegenden randomisierten, klinisch kontrollierten, prospektiven Studie war es, die Leistungsfähigkeit des Universaladhäsivs 3M™ Scotchbond™ Universal (SBU) bei dessen Anwendung an nicht kariösen Zahnhalsläsionen (NCCL) klinisch und mit optischer Kohärenztomografie (OCT) zu bewerten. An 55 Patienten wurde das Universaladhäsiv in den Konditionierungsmodi self-etch (SE, n = 55), selective-enamel-etch (SEE, n = 55) und etch-and-rinse (ER, n = 55) in Kombination mit dem Komposit Filtek™ Supreme XTE angewendet. Das etablierte Etch-and-rinse-Adhäsiv OptiBond™ FL (OFL) diente als Referenzsystem (n = 55). Die Restaurationen wurden nach 14 Tagen (Baseline), sechs und 12 Monaten klinisch untersucht (FDI-Kriterien). Parallel dazu erfolgte die quantitative Bewertung der interfazialen Spaltformationen am Schmelz und Dentin/Zement mit OCT, welche erstmals bereits direkt nach Füllungslegung vorgenommen wurde. Die kumulativen Fehlerraten (CFR), die klinischen Parameter Randverfärbung, Randadaptation und Frakturen/Retention, sowie die gemittelten adhäsiven Defekte pro Gruppe wurden statistisch ausgewertet. Nach 12 Monaten ergaben sich in allen Gruppen mit SBU signifikant geringere kumulative Fehlerraten als in der Kontrollgruppe OFL. Unmittelbar nach Füllungslegung sowie nach sechs und 12 Monaten konnten an der Schmelz-Komposit-Interface in der Gruppe SBU/SE mehr adhäsive Defekte als in den Gruppen SBU/SEE und OFL nachgewiesen werden. An der dominierenden Dentin/Zement-Komposit-Interface zeigte sich hingegen in der Gruppe OFL generell ein signifikant höheres Verbundversagen. Sowohl die klinische als auch die tomografische Bewertung ergaben ein geringeres Verbundversagen in den Gruppen mit SBU im Vergleich zu OFL. Dabei resultierte auch aus der unbeabsichtigten Phosphorsäureätzung am Dentin bei selektiver Schmelzätzung kein Nachteil. Mit OCT konnten signifikante Gruppenunterschiede früher als mit der klinischen Bewertung, nämlich bereits unmittelbar nach Füllungslegung, dargestellt und reproduziert werden. Das verdeutlicht die hohe Sensitivität und Reliabilität der Methode zur Bewertung des Zahn-Komposit-Verbundes und lässt sehr viel frühere Aussagen zur klinischen Bewährung von Systemen zur Restauration mit Kompositen zu.

INTRODUCTION: Schizophrenia (SZ) and bipolar disorder (BD) are neurodegenerative psychotic disorders hallmarked by reductions in gray and white matter volume. Limitations in neuroimaging have led to the use of OCT to study retinal layer biomarkers and their relation to brain pathology. This thesis includes a meta-analysis of current literature and an exploratory analysis of retinal layer thickness in relation to SZ and BD. METHODS: For the meta-analysis, twelve articles were identified using PubMed, Web of Science, and Cochrane database. Diagnostic groups were proband (SZ and BD combined), SZ only, BD only, and healthy control (HC) eyes. Analyses utilized fixed and random effects models, in addition to assuring that bias was adjusted for and that results were cross-validated. Statistical analyses were performed using the “meta” package in R, with results reported as standard mean differences (SMD). The exploratory analysis included a total of 38 subjects (24 probands and 14 HC). Retinal measures were co-varied for age, sex, race, body mass index (BMI), and best-corrected visual acuity (BCVA). Correlations between retinal and clinical and cortical measures were also performed. Clinical data included illness duration, symptom severity, antipsychotic dosage, and smoking status. Neuroimaging data included gray matter (GM) thickness, gray matter volume, and intracranial volume (ICV). Linear effects and mixed effects models were used to study mean eye and right/left eye measures, respectively. Statistical analysis was done in R. RESULTS: A total of 820 patient eyes (541 SZ and 279 BD) and 904 HC eyes were used for the meta-analysis. Compared to HC eyes, probands, SZ, and BD eyes showed significant thinning the peripapillary retinal nerve fiber layer (RNFL), with atrophy greatest in the nasal, temporal, and superior regions. In addition, all diagnostic groups demonstrated significant reductions in the combined ganglion cell layer and inner plexiform layer (GCL-IPL) compared to HC. No significant differences were found for choroidal and macular measures. No significant relationships were seen from meta-regression analysis for clinical measures. For the exploratory analysis, retinal measures from a total of 24 probands (18 SZ and 6 BD) and 14 HC was studied. Compared to HC, probands showed reductions in overall RNFL in mean eye measures, while increases in the inner and outer RNFL were seen in left eye measures. No significant group differences were seen in the GCL, IPL, and inner nuclear layer (INL). The outer plexiform layer (OPL) showed significant thickening in probands and SZ compared to HC for all eye measures. Probands showed trending reductions in the outer nuclear layer (ONL) in the left eye compared to HC. No significant correlations were found between retinal layers and illness duration, overall PANSS (Positive and Negative Syndrome Scale) score, PANSS negative symptom subscore, and smoking status. PANSS positive symptom subscore showed significant and trending negative correlations to the RNFL and GCL, respectively. Antipsychotic medication dosage displayed a trending negative relationship with the IPL. GM thickness showed a significant and trending negative correlation to the RNFL and ONL, respectively. Furthermore, a trending inverse relationship was observed between GM volume and the OPL. Finally, ICV demonstrated a trending and significant negative relationship with GCL and OPL thickness, respectively. CONCLUSION: The meta-analysis showed that atrophy in RNFL and GCL-IPL measures are widely associated with psychosis. Furthermore, it supports previous findings of gray and white matter reductions in SZ and BD. The exploratory analysis showed psychosis-associated reductions in the RNFL and ONL layers, consistent with previous literature. Contradictory findings, the thickening of the ONL, can be attributed to the conflicting findings, but might also be explained by neuro-inflammatory pathways related to psychotic disorders.

Photobiomodulation (PBM) therapy involves the irradiation of tissues with red to near- infrared (NIR) light at low power densities to stimulate healing, reduce inflammation, and promote optimal cellular functioning. These beneficial effects are thought to occur due to the absorption of NIR light by the chromophore, and terminal enzyme in the mitochondrial electron transport chain, cytochrome c oxidase (CCO). It is hypothesized that increased oxygen consumption due to the photostimulation of CCO, as well as photodissociation of the vasodilator nitric oxide from its binding site in the binuclear center of CCO, contribute to improved tissue healing by increasing blood flow to the irradiated region. Applied to the brain, PBM therapy has the potential to improve many neurological injuries and diseases for which reduced cerebral blood flow (CBF) is a common finding. This study examines whether cortical irradiation with NIR light has an impact on CBF in mice. Mice were administered brain PBM via 810nm, 190mW LED for 18 minutes. CBF was measured before, during, and after treatment using Doppler Optical Coherence Tomography. Results from 16 trials demonstrated a significant, 40% increase in CBF during NIR treatment. This CBF increase was not observed during control trials. Additionally, irradiation with a 730nm LED did not increase CBF, indicating that the blood flow increase observed with 810nm irradiation was not simply due to tissue heating. These findings provide support for the value of PBM therapy for the treatment of neurological conditions. / 2023-05-14T00:00:00Z

In dentistry optical coherence tomography (OCT) technology has shown some promise as a method to distinguish between enamel, dentin, and restorative materials of tooth specimens. Ultrasound (US) technology has been reported with applications in dentistry to image deep tissues which offers a means to further characterize various soft tissue anomalies. While it is believed that both US and OCT technologies have real-time imaging potential for dentistry, their ability to visualize multiple types of simulated defects within root canal systems has yet to be tested. This study was setup to help determine the efficacy of two catheter-based imaging probes in prepared root canals containing areas of interest. Areas of interest herein are cited as vertical fracture lines, simulated perforations, resorptive-like defects, sites of intact dentin, and void space variance of the lumen. 33 human teeth were selected and underwent root canal analysis using 2 commercially available intravascular catheter-based imaging probes integrated with either OCT or US technology. This study proved that intravascular OCT is a very powerful imaging modality capable of (1) detecting various areas of endodontic interest, (2) yielding superficial imaging data of root canal architecture, and (3) trans-imaging tooth specimens from the canal lumen to the external surface of intact teeth at various cross-sections. Intravascular US probe was not capable of producing useful imaging data per the methodology herein. To date there are no FDA approved OCT probes commercially available for use in endodontics. Hopefully this study furthers our understanding of how useful and multimodal OCT technology truly is.

Indiana University-Purdue University Indianapolis (IUPUI) / Erosive tooth wear (ETW) is an emerging dental condition manifested clinically as tooth surface loss, eventually impairing the teeth’s structural integrity, function, and esthetics. Both research and practice are in need of a quantitative, non-destructive method to monitor ETW. Cross-polarization optical coherence tomography (CP-OCT), an advanced imaging tool, shows great potential to fulfill this need, but its feasibility and shortcomings remain unclear. In this dissertation, I explored the capability of CP-OCT to monitor ETW in three in vitro studies, one per chapter. Chapter 2 investigated the effects of enamel surface roughness and dental erosion severity on CP-OCT dental surface loss measurements. Chapter 3 tested the effects of enamel surface roughness and dental erosion on CP-OCT enamel thickness measurements at different simulated wear levels. Chapter 4 explored the ability of CP-OCT to quantify the thickness of natural and wornout enamel surfaces and to estimate longitudinally the wear depths resulting from simulated wear. I concluded: (1) enamel surface roughness did not affect CP-OCT measurements of enamel surface loss, however, the estimated error limited the appropriate assessment of the initial stages of dental erosion surface loss using CP-OCT; (2) enamel surface roughness and dental erosion did not affect CP-OCT enamel thickness measurements, and the CP-OCT differentiated the simulated enamel wear levels; and (3) CP-OCT quantified thickness of natural enamel before, during, and after the tooth wear simulation and allowed wear depth estimation following the simulated wear. / 2021-07-03

The purpose of this work was to develop novel optical imaging technology and algorithms as a nondestructive method for detection and diagnosis of cancer in breast specimens. There are many ways in which the diagnosis of disease can benefit from fast and intelligent optical imaging technology. Our existing ability to provide this diagnosis depends on time-consuming pathology analysis. Optical coherence tomography (OCT) is a non-invasive optical imaging modality that provides depth-resolved, high-resolution images of tissue microstructure in real-time. OCT could provide a rapid evaluation of specimens while patients are still in the office, and has strong potential to improve the efficiency in evaluation of breast pathology specimens (biopsy or surgical). In this work, we demonstrate an imaging system to address this unmet clinical need, artificial intelligence algorithms to interpret the images, and early work towards miniaturizing the technology. We present an OCT system that achieves a line scan rate of 250kHz, meaning we can image a pathology cassette in 41 seconds, which is more than double the fastest scan rate in the field. By utilizing a multiplexed superluminescent diode (SLD) light source, which has strong noise performance over imaging speed, we achieve high resolution imaging under 5 um in tissue (axially and laterally). The system features a 1.1 mm 6-dB sensitivity fall-off range when imaging at 250 kHz. The scanner features large-area scanning with the implementation of a 2-axis motorized stage, enabling visualization of areas up to 10 cm x 10 cm (prior work visualizes 3 mm x 3mm). We showcase the results of demonstrating the performance of this system on a 100-patient clinical imaging study of breast biopsies, as well as imaging of clinical pathology specimens from the breast, prostate, lung, and pancreas in an IRB-approved study. Further, we show our work towards developing artificial intelligence (AI) for cancer detection within OCT images. Using retrospective data, we developed a type of AI algorithm known as a convolutional neural network (CNN) to classify OCT images of breast tissue from 49 patients. The binary cancer classification achieved 94% accuracy, 96% sensitivity, and 92% specificity. This framework had higher accuracy than the 88% accuracy of 7 clinician readers combined in our lab’s earlier multi-reader study. Lastly, we demonstrate a supercontinuum light source based on a 1 mm2 Si3N4 photonic chip for OCT imaging that has better performance than the state-of-the-art laser. Existing broadband laser sources for OCT are large, bulky, and have high excess noise. Our Si3N4 chip fundamentally eliminates the excess noise common to lasers and achieves 105 dB sensitivity and 1.81 mm 6-dB sensitivity roll-off with only 300 µW power on the sample.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18875号 / 医博第3986号 / 新制||医||1008(附属図書館) / 31826 / 京都大学大学院医学研究科医学専攻 / (主査)教授 森田 智視, 教授 福山 秀直, 教授 大森 治紀 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

Final publication is available at http://www.sciencedirect.com/science/article/pii/S0002939414000488 / 京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19586号 / 医博第4093号 / 新制||医||1014(附属図書館) / 32622 / 京都大学大学院医学研究科医学専攻 / (主査)教授 大森 孝一, 教授 宮本 享, 教授 横出 正之 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM