Phase-Retrieved Tomography enables imaging of a Tumor Spheroid in Mesoscopy Regime

Optical tomographic imaging of biological specimen bases its reliability on the combination of both accurate experimental measures and advanced computational techniques. In general, due to high scattering and absorption in most of the tissues, multi view geometries are required to reduce diffuse halo and blurring in the reconstructions. Scanning processes are used to acquire the data but they inevitably introduces perturbation, negating the assumption of aligned measures. Here we propose an innovative, registration free, imaging protocol implemented to image a human tumor spheroid at mesoscopic regime. The technique relies on the calculation of autocorrelation sinogram and object autocorrelation, finalizing the tomographic reconstruction via a three dimensional Gerchberg Saxton algorithm that retrieves the missing phase information. Our method is conceptually simple and focuses on single image acquisition, regardless of the specimen position in the camera plane. We demonstrate increased deep resolution abilities, not achievable with the current approaches, rendering the data alignment process obsolete.Comment: 21 pages, 5 figure

Characterisation of Microparticle Waste from Dental Resin-Based Composites

Clinical applications of resin-based composite (RBC) generate environmental pollution in the form of microparticulate waste. Methods: SEM, particle size and specific surface area analysis, FT-IR and potentiometric titrations were used to characterise microparticles arising from grinding commercial and control RBCs as a function of time, at time of generation and after 12 months ageing in water. The RBCs were tested in two states: (i) direct-placement materials polymerised to simulate routine clinical use and (ii) pre-polymerised CAD/CAM ingots milled using CAD/CAM technology. Results: The maximum specific surface area of the direct-placement commercial RBC was seen after 360 s of agitation and was 1290 m2/kg compared with 1017 m2/kg for the control material. The median diameter of the direct-placement commercial RBC was 6.39 μm at 360 s ag-itation and 9.55 μm for the control material. FTIR analysis confirmed that microparticles were sufficiently unique to be identified after 12 months ageing and consistent alteration of the outermost surfaces of particles was observed. Protonation-deprotonation behaviour and the pH of zero proton charge (pHzpc) ≈ 5–6 indicated that the particles are negatively charged at neutral pH7. Conclusion: The large surface area of RBC microparticles allows elution of constituent monomers with potential environmental impacts. Characterisation of this waste is key to understanding potential mitigation strategies

Preserving Venetian Bell Towers Through Virtual Experiences

This project aimed to aid in the preservation of Venetian bell towers by updating the VPC bell tower database through documenting their state and creating virtual experiences. It was achieved by collecting extensive written, visual, and audio data of the towers and bells. Then the Matterport 3D Pro Camera was used to create virtual tours of the 17 bell towers and 71 bells documented in the sestieri of Dorsoduro, San Polo, and Santa Croce. Most towers and bells were in fair and average condition, respectively, with three towers needing major repairs and two cracked bells. The resulting data was added to bells.veniceprojectcenter.org. A mobile data collection application was created to assist future groups and campanologists in recording consistent and comprehensive data

진동기구가 Bulk-Fill 복합 레진의 내부 적합도와 기포 생성에 미치는 영향

학위논문(박사) -- 서울대학교대학원 : 치과대학 치의과학과, 2022. 8. 백승호.Objectives. The aim of this study was to investigate the effects of vibration on internal adaptation and void formation of bulk-fill composite resin, according to different frequencies of vibration devices and layering thickness of composite resin. Methods. The change of complex viscosity when oscillating shear was applied to the Filtek Bulk Fill (FB) composite resin was measured using a rotational rheometer. The frequency and amplitude of two vibration devices (COMO and SONICflex) were measured using a scanning laser doppler vibrometer (SLDV). After preparing cylindrical class I cavities on CAD/CAM hybrid composite blocks, FB was filled using different layering thicknesses (2 mm, 4 mm) and vibration methods (No vibration, COMO, SONICflex) (n = 10). The internal adaptation (2D void area % at the bottom surface) and void formation (3D void volume %) were measured using micro-computed tomography. The median values of the 2D void area (%) and 3D void volume (%) were analyzed using the Kruskal-Wallis test, followed by post-hoc Mann-Whitney U test. Results. Complex viscosity of FB decreased with increasing frequency of applied oscillation. The frequency and amplitudes of COMO were 149.1 Hz and, 50.5 µm (vertical), 26.4 µm (horizontal) while those of SONICflex were 4,818.9 Hz and 52.1 µm (vertical), 23.3 µm (horizontal). With 2 mm incremental layering, vibration methods demonstrated significantly lower bottom surface void area and lower total void volume than no vibration methods (p 0.05). Both vibration devices with different frequencies showed no significant difference in internal adaptation and void volume. Conclusion. Using vibration devices with 2 mm incremental layering can enhance the internal adaptation and reduce the void volume of bulk-fill composite resin.1. 연구 목적 본 연구의 목적은 Bulk-Fill 복합 레진 수복 시 진동기구의 사용과 적층 두께가 복합 레진의 내부 적합도와 기포 생성에 미치는 영향을 알아보고자 하는 것이다. 2. 재료 및 방법 회전형 점성계를 이용하여 Filtek Bulk Fill (FB) 복합 레진에 진동 전단을 가했을 때의 복소 점도 변화를 측정하였다. 두 가지 진동기구(COMO, SONICflex)의 진동수와 진폭을 스캐닝 레이져 도플러 진동계(SLDV)를 이용하여 측정하였다. CAD/CAM 용 하이브리드 컴포짓 블록에 실린더 형태의 1급 와동을 형성한 후 적층 두께 (2 mm, 4 mm) 및 진동 방법 (No vibration, COMO, SONICflex)을 달리하여 복합 레진을 수복하였다 (n=10). 수복된 복합 레진의 내부 적합도 (2D 바닥면의 기포 면적 %) 및 기포 생성 (3D 기포 부피 %)을 마이크로 CT를 이용하여 측정하였다. Kruskal-Wallis 와 Mann-Whitney U test 로 진동 기구 및 적층 방법이 복합레진의 적합도 및 기포 생성에 미치는 영향을 분석하였다. 3. 결과 FB 복합 레진의 복소 점도는 가해지는 진동의 진동수가 커짐에 따라 감소하였다. 측정된 COMO의 진동수 및 진폭은 149.1 Hz, 50.5 µm (수직), 26.4 µm (수평), SONICflex의 진동수 및 진폭은 4818.9 Hz, 52.1 µm (수직), 23.3 µm (수평)이었다. 2 mm 적층 수복 시, 복합 레진에 진동을 가하였을 때 통계적으로 유의하게 바닥면의 기포 면적 감소 및 전체 기포 부피가 감소하였다 (p 0.05). 서로 다른 진동수의 두 진동 기구 사이에는 적합도와 기포 생성에 통계적으로 유의한 차이를 보이지 않았다. 4. 결론 진동기구를 사용하여 2 mm 적층 수복을 하였을 때 bulk-fill 복합 레진의 내부 적합도 증가하였고 기포가 감소하였다.1. Introduction 1 2. Materials and Methods 5 3. Results 12 4. Discussion 17 5. Conclusion 23 6. References 24 Tables and Figures 30 Abstract in Korean 41박

Terrestrial laser scanner for monitoring the deformations and the damages of buildings

The paper presents the use of the terrestrial laser scanner for the study and the assessment of damaged buildings. The terrestrial laser scanner provides the ability to detect the geometric 3D model of a building without any physical contact with the structure. Knowledge of the 3D model will give the opportunity to study the deformation and quantify the damages. Three case studies are presented relating to damaged and/or unsafe buildings: Sivillier Castle (Villasor - Sardinia- Italy), the Bell Tower of Mores (Sardinia-Italy) and industrial building (Cagliari - Italy). The first two cases concern buildings of historical and architectural importance that present a state of compromised conservation; the last, an industrial building compromised by fire. In all cases, a laser scanner survey was carried out that not only provided valuable information but also highlighted structural metric deformation and degradation

TERRESTRIAL LASER SCANNER FOR MONITORING THE DEFORMATIONS AND THE DAMAGES OF BUILDINGS

scanner provides the ability to detect the geometric 3D model of a building without any physical contact with the structure. Knowledge of the 3D model will give the opportunity to study the deformation and quantify the damages. Three case studies are presented relating to damaged and/or unsafe buildings: Sivillier Castle (Villasor - Sardinia- Italy), the Bell Tower of Mores (Sardinia-Italy) and industrial building (Cagliari - Italy). The first two cases concern buildings of historical and architectural importance that present a state of compromised conservation; the last, an industrial building compromised by fire. In all cases, a laser scanner survey was carried out that not only provided valuable information but also highlighted structural metric deformation and degradation

A scanning device for wide band infrared reflectography

Diagnostics in the cultural heritage field is an important resource to investigate art history, issues, execution techniques, materials and state of conservation of an artwork. In this field the main concern is preservation and, for this reason, new non-invasive and non-destructive technologies have been developed. At the Department of Physics in Ferrara, imaging for cultural heritage, using electromagnetic radiation, from visible light to X-rays is applied and studied. A diagnostics protocol has been defined to standardize the study approach on paintings considering that each painting is a particular case, and the protocol must be adapted to the needs that the artwork itself requires. This work consists in the development of a scanning devices for wide band infrared Reflectography, to extend the applications of the reflectographic technique, and how it is inserted in the diagnostic protocol. Infrared reflectography use the electromagnetic radiation of Near-IR to investigate the underdrawing in paintings. The success of IR Reflectography to reveal the underdrawing in paintings since XIV up to XVI century depends on the peculiar technique of painters in that period. Thin and uniform pictorial layers, covering high contrast drawings on white priming allow a good detection of underdrawing details. Paintings of late sixteenth century have dark preparations and thick paint layers, so Reflectography doesn’t get the same good results. Extension of the spectral band to longer wavelengths, up to 2,5 μm, is a tool to improve reflectographic capability

Comparison of osseointegration in piezoimplants versus cylindrical implants

BACKGROUND: Dental implants have been successful for the restoration of edentulous areas, but current techniques are inadequate in areas lacking sufficient bone volume. Piezoelectric surgery has shown encouraging effects on both osseous healing. A new wedge-shaped titanium PiezoImplant requires piezoelectric osteotomy. This study compares PiezoImplants to conventional threaded cylindrical shaped implants by microcomputed tomography and histology to assess osseointegration, tissue response, and alveolar ridge changes. METHODS: After 3 months post-extraction, 18 conventional cylindrical implants and 18 wedge-shaped PiezoImplants were placed using a split-mouth design in 3 adult mini pigs. The cylindrical implant sites were prepared for osteotomy with rotary instrumentation while the PiezoImplant sites were prepared with piezoelectric surgical inserts. One animal was sacrificed at 4, 8, and 12 weeks post operation. Quantitative µCT and histological analysis evaluated bone volume, osseointegration, and post-operative cellular events. RESULTS: The results of a multivariable linear regression model demonstrated that the PiezoImplants, arch location, and time were significant factors on higher BV/TV percentage. Bone to implant contact (BIC) analysis by high resolution microscopy and histomorphometry indicated osseointegration though intimate contact between implants and adjacent alveolar bone in both groups. The tissue response displayed no evidence of abnormal healing and the PiezoImplant was classified as a non-irritant. CONCLUSION: The combination of piezoelectric osteotomy and newly designed PiezoImplants had favorable effects on wound healing and osseointegration compared to conventional cylindrical implants. These novel wedge-shaped implants may be beneficial for narrow ridge spaces without additional ridge augmentation. Further research is needed to establish clinical validity