Assessing seismic collapse of structures using digital cloning techniques.

Rapid, reliable information on earthquake-affected structures' current damage/health conditions and predicting what would happen to these structures under future seismic events play a vital role in accelerating post-event evaluations, leading to optimized on-time decisions. Such rapid and informative post-event evaluations are crucial for earthquake-prone areas, where each earthquake can potentially trigger a series of significant aftershocks, endangering the community's health and wealth by further damaging the already-affected structures. Such reliable post-earthquake evaluations can provide information to decide whether an affected structure is safe to stay in operation, thus saving many lives. Furthermore, they can lead to more optimal recovery plans, thus saving costs and time. The inherent deficiency of visual-based post-earthquake evaluations and the importance of structural health monitoring (SHM) methods and SHM instrumentation have been highlighted within this thesis, using two earthquake-affected structures in New Zealand: 1) the Canterbury Television (CTV) building, Christchurch; 2) the Bank of New Zealand (BNZ) building, Wellington. For the first time, this thesis verifies the theoretically- and experimentally validated hysteresis loop analysis (HLA) SHM method for the real-world instrumented structure of the BNZ building, which was damaged severely due to three earthquakes. Results indicate the HLA-SHM method can accurately estimate elastic stiffness degradation for this reinforced concrete (RC) pinched structure across the three earthquakes, which remained unseen until after the third seismic event. Furthermore, the HLA results help investigate the pinching effects on the BNZ building's seismic response. This thesis introduces a novel digital clone modelling method based on the robust and accurate SHM results delivered by the HLA method for physical parameters of the monitored structure and basis functions predicting the changes of these physical parameters due to future earthquake excitations. Contrary to artificial intelligence (AI) based predictive methods with black-box designs, the proposed predictive method is entirely mechanics-based with an explicitly-understandable design, making them more trusted and explicable to stakeholders engaging in post-earthquake evaluations, such as building owners and insurance firms. The proposed digital clone modelling framework is validated using the BNZ building and an experimental RC test structure damaged severely due to three successive shake-table excitations. In both structures, structural damage intensifies the pinching effects in hysteresis responses. Results show the basis functions identified from the HLA-SHM results for both structures under Event 1 can online estimate structural damage due to subsequent Events 2-3 from the measured structural responses, making them valuable tool for rapid warning systems. Moreover, the digital twins derived for these two structures under Event 1 can successfully predict structural responses and damage under Events 2-3, which can be integrated with the incremental dynamic analysis (IDA) method to assess structural collapse and its financial risks. Furthermore, it enables multi-step IDA to evaluate earthquake series' impacts on structures. Overall, this thesis develops an efficient method for providing reliable information on earthquake-affected structures' current and future status during or immediately after an earthquake, considerably guaranteeing safety. Significant validation is implemented against both experimental and real data of RC structures, which thus clearly indicate the accurate predictive performance of this HLA-based method

Self-Assembling Peptides for Cartilage Regeneration

Loss of glycosaminoglycans (GAGs) in osteoarthritic (OA) cartilage contributes to a decrease in mechanical properties and function in vitro, and is considered to be a major contributor to disease progression. The aims of this investigation were to test the hypothesis that a combination of self-assembling peptides (SAPs) and chondroitin sulfate (glycosaminoglycan; GAG) would restore the biomechanical properties of GAG depleted porcine condylar cartilage, ideally to a level intrinsic to native porcine condylar cartilage. The SAPs investigated were members of the P11 series which have been designed to spontaneously self-assemble into three-dimensional fibrilar hydrogels, in response to physiological conditions. Initial studies were carried out to determine which of three peptides (P11-4, P11-8 and P11-12) demonstrated high β-sheet percentage, long-woven fibrilar networks and high stiffness; when mixed with chondroitin sulfate at two different GAG molar ratios (1:16 and 1:64) in physiological conditions, using FTIR analysis, transmission electron microscopy and rheology. The β-sheet percentage, dimensions of fibrils and stiffness were dependent upon the peptide, GAG molar ratio and Na2+ salt concentration. P11-4 and P11-8: GAG mixtures had high β-sheet percentage ranging from 50.6-91 % and 81.7-92 %, respectively. Fibril lengths of the P11-4 and P11-8: GAG mixtures were in the range 498- 3518 nm and the elastic shear modulus (G’) ranged from 4,479-10,720 Pa and 7,722-26,854 Pa, respectively. P11-4 and P11-8: GAG mixtures were selected for further investigation. In order to produce a GAG depleted cartilage model, porcine femoral condylar cartilage was subjected to three different methods of GAG depletion (1) coating the surface with chondroitinase ABC (2) injecting chondroitinase ABC into the cartilage (3) washing the condyles in sodium dodecyl sulfate (SDS). GAG depletion was successfully achieved following two 24 hour washes in 0.1 % (w/v) SDS and buffer washes. Histological analysis of safranin O stained sections revealed an absence of GAGs. Quantification of GAGs using the dimethylemethylene blue assay revealed that 75 % of GAGs had been removed. In order to assess the effects of peptide: GAG mixtures on the biomechanical properties of the GAG depleted porcine condylar cartilage a biomechanical test method was developed. A series of indentation tests using different loads, followed by finite element analysis of the data were performed on native and GAG depleted porcine condylar cartilage; to identify a suitable load for detection of a significant difference in the deformation, equilibrium elastic modulus and permeability between the native and GAG depleted porcine condylar cartilages. A load of 0.31 N was identified as the most appropriate. GAG depleted porcine condylar cartilage was injected with P11-4 and P11-8 alone, P11-4 and P11-8 : GAG mixtures at a molar ratio of 1:64 and chondroitin sulfate alone. The average percentage deformation of the medial condylar cartilage samples injected with P11-4 alone and P11-4: GAG mixture was 15.5 % and 8.7 % and for P11-8 alone and P11-8: GAG mixture was 11.4 % and 9.1 % respectively; compared to 6.3 % for the native cartilage and 12.6 % for the GAG depleted cartilage. The average equilibrium elastic modulus of the medial cartilage samples injected with P11-4 alone and P11-4: GAG mixture was 0.16 MPa and 0.43 MPa and for P11-8 alone and P11-8: GAG, 0.23 MPa and 0.35 MPa, respectively; compared to 0.49 MPa for the native cartilage and 0.21 MPa for the GAG depleted cartilage. Statistical analysis (ANOVA) showed that a mixture of P11-4: GAG, but not P11-8: GAG restored both the percentage deformation and equilibrium elastic modulus of the GAG depleted cartilage to levels that were not significantly different to the native cartilage. This study has shown that the use of P11-4 in combination with chondroitin sulfate has future potential for development as a minimally invasive treatment for early stage osteoarthritis

Cartilage Tissue Engineering For Rhinoplasty

Nasal surgery (rhinoplasty) has evolved considerably since its origins in Egypt around 1600BCE, yet modern reconstruction still relies on grafts harvested from autologous rib cartilage. Rib cartilage is an excellent graft material, but chest donor site morbidity can be a significant problem. The aim of this thesis was to create a patient specific cartilage surgical product using autologous stem cells that would provide surgeons with an effective alternative to rib cartilage. Adipose-derived stem cells (ADSCs) and cartilage-derived stem/precursor cells (CSPCs) were used in this thesis as they can be harvested through minimally invasive procedures and their chondrogenic potential already widely established. Using a novel tissue clearing protocol for whole mount imaging, primary experiments confirmed the ability of both cell types to self-organize and generate cartilage-like extracellular matrix (ECM) in 3D spheroids. Three different methods of engineering cartilage in 3D were investigated. Firstly, a clinically approved collagen matrix was used as a scaffold and seeded with cells. Immunocytochemistry and histological staining demonstrated cartilage like ECM on the scaffold surface in preference to deeper regions. The collagen matrix proved too be tight and constrictive on cell expansion. Secondly, a 3D bioprinter was used to print cells mixed with cellulose/alginate “bioink” hydrogels. This bioink failed to demonstrate cartilage like ECM in static culture and in a chick embryo chorioallantoic membrane (CAM) model. Lastly, a cell laden fibrin hydrogel was “sandwiched” between 2 layers of polycaprolactone (PCL) sheets to provide mechanical support and grafted onto CAM. Histological analysis of cell laden fibrin confirmed regions of chondrogenesis by positive staining of collagen and glycosaminoglycans. In conclusion, the results provide further understanding of how these cells respond to different 3D environments and the effect on chondrogenesis. Combining 3D bioprinting with a sandwich design may be an effective future approach to product development

Neutrophil biomechanical properties and immune function in health and inflammatory disease

Low density granulocytes (LDGs) are a poorly understood class of immune cells found in patients with chronic inflammatory diseases including psoriasis and systemic lupus erythematosus (SLE). Research completed at the National Institutes of Health (NIH) revealed that in the context of SLE, LDGs release higher levels of type 1 interferons, undergo increased NETosis, and accordingly drive inflammation. Meanwhile, advances in mechanical phenotyping at the University of Cambridge have driven hypotheses of neutrophil trafficking and immune function being intimately linked to cellular biomechanical properties (e.g. density, stiffness, morphology). This thesis analyses the intersection of immune cellular biomechanical phenotypes and their function. Specifically, it focuses on the role of neutrophils and LDGs in inflammatory diseases. In this thesis, real-time deformability cytometry (RT-DC) was optimised as a high-throughput mechanical phenotyping technique for the analysis of neutrophils. This enabled development of a protocol to recover purified neutrophils to their whole blood mechanical phenotype. Neutrophil biomechanical properties were analysed by RT-DC, lattice light-sheet microscopy, confocal microscopy and scanning electron microscopy. Neutrophil immunologic functions (e.g. NETosis, macropinocytosis) were imaged using florescence microscopy. To analyse the contribution of biomechanical properties to neutrophil trafficking, a novel microfluidic microvasculature mimetic was developed. An endothelial flow assay was used to image neutrophils interacting with endothelial cells. Finally, the complete proteomes and phosphoproteomes of LDGs and normal dense neutrophils (NDNs) were obtained from five healthy donors and five SLE patients. Several key insights were gained. Firstly, hypotonic lysis and magnetic column-based isolation techniques are damaging to neutrophil biomechanical properties, but purification of neutrophils retaining their biomechanical properties can be achieved by using gradients and column-free magnetic systems followed by recovery at 37 degrees Celsius. Secondly, the biphasic biomechanical kinetics of neutrophil priming were described; cells contract briefly before immediately expanding. The expansion phase was determined to be macropinocytosis dependent. Thirdly, SLE LDGs are phenotypically rougher than autologous SLE NDNs or healthy LDGs. This appears to impact their microvasculature trafficking abilities, as SLE LDGs were increasingly trapped in the narrow channels of a three- dimensional microvasculature mimetic. These results suggest a role for biomechanical properties in modulation of neutrophil trafficking, indicating that SLE LDGs may be increasingly retained in microvasculature networks, similar to what has been described for primed neutrophils. Finally, unbiased proteomics quantified 4109 proteins and 875 phosphoproteins in four neutrophil subsets (healthy unstimulated NDNs, healthy primed NDNs, SLE NDNs, and SLE LDG). This shed new light into neutrophil heterogeneity at the protein level and to my knowledge, is the first proteomic profile of the SLE LDG. In addition to findings pertaining to SLE LDG biology and function, differential phosphorylation of proteins associated with cytoskeletal organisation were identified in SLE LDGs relative to SLE NDNs, suggesting a phosphoproteomic explanation for the SLE LDGs’ distinct biomechanical phenotype. When taken together, this work could have important pathogenic implications in the context of SLE manifestations in various organs and the development of small vessel vasculopathy.Kathleen Bashant was funded by the NIH-Cambridge Scholars Program This research was supported by the NIHR Cambridge Biomedical Research Centre (BRC-1215-20014*). The views expressed are those of the author and not necessarily those of the NIHR or the Department of Health and Social Care

Earthquake Engineering

The book Earthquake Engineering - From Engineering Seismology to Optimal Seismic Design of Engineering Structures contains fifteen chapters written by researchers and experts in the fields of earthquake and structural engineering. This book provides the state-of-the-art on recent progress in the field of seimology, earthquake engineering and structural engineering. The book should be useful to graduate students, researchers and practicing structural engineers. It deals with seismicity, seismic hazard assessment and system oriented emergency response for abrupt earthquake disaster, the nature and the components of strong ground motions and several other interesting topics, such as dam-induced earthquakes, seismic stability of slopes and landslides. The book also tackles the dynamic response of underground pipes to blast loads, the optimal seismic design of RC multi-storey buildings, the finite-element analysis of cable-stayed bridges under strong ground motions and the acute psychiatric trauma intervention due to earthquakes

Advances in Mechanical Systems Dynamics 2020

The fundamentals of mechanical system dynamics were established before the beginning of the industrial era. The 18th century was a very important time for science and was characterized by the development of classical mechanics. This development progressed in the 19th century, and new, important applications related to industrialization were found and studied. The development of computers in the 20th century revolutionized mechanical system dynamics owing to the development of numerical simulation. We are now in the presence of the fourth industrial revolution. Mechanical systems are increasingly integrated with electrical, fluidic, and electronic systems, and the industrial environment has become characterized by the cyber-physical systems of industry 4.0. Within this framework, the status-of-the-art has become represented by integrated mechanical systems and supported by accurate dynamic models able to predict their dynamic behavior. Therefore, mechanical systems dynamics will play a central role in forthcoming years. This Special Issue aims to disseminate the latest research findings and ideas in the field of mechanical systems dynamics, with particular emphasis on novel trends and applications

Vocal fold vibratory and acoustic features in fatigued Karaoke singers

Session 3aMU - Musical Acoustics and Speech Communication: Singing Voice in Asian CulturesKaraoke is a popular singing entertainment particularly in Asia and is gaining more popularity in the rest of world. In Karaoke, an amateur singer sings with the background music and video (usually guided by the lyric captions on the video screen) played by Karaoke machine, using a microphone and an amplification system. As the Karaoke singers usually have no formal training, they may be more vulnerable to vocal fatigue as they may overuse and/or misuse their voices in the intensive and extensive singing activities. It is unclear whether vocal fatigue is accompanied by any vibration pattern or physiological changes of vocal folds. In this study, 20 participants aged from 18 to 23 years with normal voice were recruited to participate in an prolonged singing task, which induced vocal fatigue. High speed laryngscopic imaging and acoustic signals were recorded before and after the singing task. Images of /i/ phonation were quantitatively analyzed using the High Speed Video Processing (HSVP) program (Yiu, et al. 2010). It was found that the glottis became relatively narrower following fatigue, while the acoustic signals were not sensitive to measure change following fatigue. © 2012 Acoustical Society of Americapublished_or_final_versio

Psr1p interacts with SUN/sad1p and EB1/mal3p to establish the bipolar spindle

Regular Abstracts - Sunday Poster Presentations: no. 382During mitosis, interpolar microtubules from two spindle pole bodies (SPBs) interdigitate to create an antiparallel microtubule array for accommodating numerous regulatory proteins. Among these proteins, the kinesin-5 cut7p/Eg5 is the key player responsible for sliding apart antiparallel microtubules and thus helps in establishing the bipolar spindle. At the onset of mitosis, two SPBs are adjacent to one another with most microtubules running nearly parallel toward the nuclear envelope, creating an unfavorable microtubule configuration for the kinesin-5 kinesins. Therefore, how the cell organizes the antiparallel microtubule array in the first place at mitotic onset remains enigmatic. Here, we show that a novel protein psrp1p localizes to the SPB and plays a key role in organizing the antiparallel microtubule array. The absence of psr1+ leads to a transient monopolar spindle and massive chromosome loss. Further functional characterization demonstrates that psr1p is recruited to the SPB through interaction with the conserved SUN protein sad1p and that psr1p physically interacts with the conserved microtubule plus tip protein mal3p/EB1. These results suggest a model that psr1p serves as a linking protein between sad1p/SUN and mal3p/EB1 to allow microtubule plus ends to be coupled to the SPBs for organization of an antiparallel microtubule array. Thus, we conclude that psr1p is involved in organizing the antiparallel microtubule array in the first place at mitosis onset by interaction with SUN/sad1p and EB1/mal3p, thereby establishing the bipolar spindle.postprin