Studies of Lung Micromechanics via Hyperpolarized 3He Diffusion NMR

While high quality MR Images of lungs are difficult to obtain with conventional proton MRI due to the organ\u27s low tissue density, the advent of techniques in noble gas polarization have enabled MR investigations of the lung\u27s more abundant air space rather than its tissue. In addition to high-resolution images of lung ventilation, lung morphometry via gas diffusion NMR provides information about the size and shape of the microscopic airways that account for over 95% of the lung\u27s airspace. Consequently, gas diffusion NMR provides an important new tool for investigating changes in lung microstructure during macroscopic changes in lung volume. Despite decades of research into the mechanisms of lung inflation and deflation, there is little consensus about whether macroscopic changes in lung volume occur due to changes in the size and/or shape of alveoli and alveolar ducts or by alveolar recruitment and derecruitment. In this dissertation lung morphometry is performed via 3He diffusion MRI in order to measure the average alveolar depth and alveolar duct radius at multiple levels of both inspiration and expiration in in vivo human subjects and in explanted human and canine lungs. Average alveolar volume, surface area, and the total number of alveoli at each lung volume are calculated from the 3He morphometric parameters. The results suggest that human lungs inflate/deflate primarily by recruitment/derecruitment of alveoli, and that individual alveolar ducts in both human and canine lungs increase in volume non-isotropically by accordion-like extension. The results further suggest that this change in alveolar duct volume is the primary mechanism of lung volume change in canine lungs but is secondary to alveolar recruitment/derecruitment in humans

Development of lightweight fire retardant, low-smoke, high-strength, thermally stable aircraft floor paneling

Fire resistance mechanical property tests were conducted on sandwich configurations composed of resin-fiberglass laminates bonded with adhesives to Nomex honeycomb core. The test results were compared to proposed and current requirements for aircraft floor panel applications to demonstrate that the fire safety of the airplane could be improved without sacrificing mechanical performance of the aircraft floor panels

Combined flue gas cleanup process for simultaneous removal of SO\u3csub\u3ex\u3c/sub\u3e, NO\u3csub\u3ex\u3c/sub\u3e, and CO₂ -- A techno-economic analysis

Flue gas cleanup often requires the removal of SOx, NOx and CO2 in separate units before atmospheric emission. The step-wise treatment process currently in place incurs significant cost and energy penalty. A single-step adsorption process based on pressure swing adsorption (PSA) by which these impurities are removed is envisioned as an efficient means of flue gas cleanup that can be applied relatively easily. In this study, the technological and economic feasibility of a single-step separation process in which SOx, NOx and CO2 are simultaneously removed from flue gas streams are assessed. Capital and operating costs are estimated based on sizing the equipment items and utilities needed and the potentials for increased energy efficiency are determined in relation to the required PSA performance. The energy saving potential for the adoption of 2-bed and 4-bed PSA cycle is compared to conventional FGD, SCR and CO2 capture units needed to cleanup flue gas in a step-wise fashion. The results show that energy savings can be expected when the PSA removal efficiency is greater than 90%. In the case of a 550 MW coal-fired power plant, the energy savings can be as high as 30% depending on PSA removal efficiency and cycle time. This high value can be reached when the PSA cycle time is on the order of 2 min. Overall, the PSA process is expected to lower the cleanup costs for both retrofitted and new-build power plants. This techno-economic assessment shows that the integrated single-step system can be an attractive technology when compared to multi-step systems for the removal of flue gas impurities --Abstract, page iii

Job performance in the Malaysian Public Service: the roles of job demands-resources and subjective Wellbeing

For many years the Malaysian Public Service (MPS) has placed a huge emphasis on the job performance of its civil servants. Various initiatives and programs such as the Excellent Work Culture, National Integrity Plan and Clean, Efficient and Trustworthy Campaign have been put in place by the government to improve the performance of its civil servants and public image of its healthcare provision. Nevertheless, poor job performance manifested in delays in receiving treatment, negligence during treatment, poor diagnosis and errors in the delivery of medication remain widespread and as such, the MPS has been subject to much public criticism in recent times. Because the severity of the problem has not been systematically investigated, the current situation warrants a more detailed and evidence-based investigation into job performance in the MPS and the factors related to it. The present research was conducted in order to investigate the issue of poor job performance in Malaysian public hospitals by identifying the factors that enhance or hinder job performance and testing these inter-relationships using an evidenced-based framework of job demands, job/personal resources, subjective well-being and performance. A mixed methods approach with a sequential exploratory design was employed. In Study 1, interview sessions were carried out with participants at selected hospitals. The data collected from the interviews were used to create additional items for a larger-scale survey used in the Study 2. Study 1 found that job performance in the MPS was at a ‘moderate and acceptable level’ according to participants of the study. Majority participants were very enthusiastic about their work and workplace and believed that the reporting of incidents of poor job performance by the Malaysian Public Complaints Bureau and newspapers were grossly exaggerated largely based on isolated incidents. Nevertheless, participants did acknowledge that some employees did not perform as well as they could because of problems such as work overload and negative attitudes. Study 1 revealed that six factors affected job performance in the MPS: 1) work overload, 2) civil servants’ attitudes, 3) leadership and monitoring, 4) religious and spiritual beliefs, 5) training, knowledge and experience and 6) personal issues. Based on the moderated mediation analyses conducted in Study 2, it was found that job resources predicted work engagement and a particularly positively impacted when job demands were at moderate and high levels. Work engagement in turn, positively impacted job performance. The analyses also revealed a significant relationship between personal resources and job performance through job demands and organisational commitment. The moderated mediation between personal resources, organisational commitment and job performance can be seen at all level of job demands. The findings largely appear to be consistent throughout the study in that job resources are significantly related to work engagement and personal resources with organisational commitment, which in turn affects job performance. The implications of these findings are discussed in terms of existing literature and suggestions for further research are also included

Deep Learning Approach to Key Frame Detection in Human Action Videos

A key frame is a representative frame which includes the whole facts of the video collection. It is used for indexing, classification, evaluation, and retrieval of video. The existing algorithms generate relevant key frames, but additionally, they generate a few redundant key frames. A number of them are not capable of constituting the entire shot. In this chapter, an effective algorithm primarily based on the fusion of deep features and histogram has been proposed to overcome these issues. It extracts the maximum relevant key frames by way of eliminating the vagueness of the choice of key frames. It can be applied parallel and concurrently to the video sequence, which results in the reduction of computational and time complexity. The performance of this algorithm indicates its effectiveness in terms of relevant key frame extraction from videos

Robust pedestrian detection and path prediction using mmproved YOLOv5

In vision-based surveillance systems, pedestrian recognition and path prediction are critical concerns. Advanced computer vision applications, on the other hand, confront numerous challenges due to differences in pedestrian postures and scales, backdrops, and occlusion. To tackle these challenges, we present a YOLOv5-based deep learning-based pedestrian recognition and path prediction method. The updated YOLOv5 model was first used to detect pedestrians of various sizes and proportions. The proposed path prediction method is then used to estimate the pedestrian's path based on motion data. The suggested method deals with partial occlusion circumstances to reduce object occlusion-induced progression and loss, and links recognition results with motion attributes. After then, the path prediction algorithm uses motion and directional data to estimate the pedestrian movement's direction. The proposed method outperforms the existing methods, according to the results of the experiments. Finally, we come to a conclusion and look into future study

Molecular simulations of Hofmeister ion pairing and solvation of protein building blocks in aqueous interfacial environments

In current days, computer simulation is a scientific tool to study material properties. Using computer simulation, equilibrium and nonequilibrium properties of materials can be estimated with a detailed atomistic picture which is not easily accessible with exper- imental techniques. It is widely used to get the atomistic resolution of various chemical and biophysical processes for better understanding of these processes. Molecular level understanding of stability, conformational changes and solvation properties of proteins or peptides in water or in ionic solution or in water-cosolvent (osmolytes) mixtures are research areas where lots of simulations and experimental works are ongoing. To understand these problems, we mainly focus in this thesis on two types of thermodynamic processes, solvation of different amino acid side-chains and ion pairing/ion-ion interaction in bulk water and near hydrophobic surfaces using molecular dynamics simulations. A detailed understanding of aqueous solvation of protein building blocks, namely amino acids, is very useful to understand the structural stability of proteins or peptides. The free energy estimation using molecular simulations is a useful tool to rationalize protein thermodynamics. In chapter 2, a short description of different methods to estimate free energies is presented. Most of the studies to understand thermodynamics of protein have used solvation data of small molecules or analogs as a representative of amino acid side-chains in protein or peptide. In reality, these side-chains are not free but rather attached to a peptide backbone. In chapter 3, we estimate the solvation free energy of different polar and nonpolar amino acid side-chains when they are attached to a peptide backbone to assess the reliability of such small molecules solvation data in explaining phenomena like protein folding and protein-protein association. We find all the nonpolar side-chains become remarkable less hydrophobic than what is expected from the solvation free energy data of the side-chain analogs. This finding challenges many hydrophobicity scales based on the solvation free energy data of small molecules. To analyze the origin of such reductions in hydrophobicity, solvation entropies and enthalpies of nonpolar and polar side chains in peptide backbone are also estimated in chapter 4. Solvation entropies of nonpolar side-chains in peptide backbone are found to be less unfavorable than solvation entropies of free side-chains which causes an overall hydrophobicity reduction. Cavity and dispersion contributions in the solvation free energies of nonpolar side-chains are also estimated. We find that a nonpolar side-chain sized cavity formation next to a tripeptide backbone is entropically favored over formation of similar sized cavities in bulk water, which effectively makes nonpolar side-chains less hydrophobic. The solvation enthalpies and entropies of the polar side chains are negative, but in absolute magnitude smaller compared with the corresponding analogue data. These effects almost perfectly cancel out in the solvation free energies and because of that the solvation free energies of polar side chains remain largely unaffected by the peptide backbone. Aqueous ionic solutions have vast applications from protein folding to colloidal stability, water surface tension, osmotic property. Ion specificity in protein precipitation and ion specific propensity toward air-water and hydrophobic interfaces are well known. Most of the studies focus on the single ion behavior. The nature of ion-ion interaction near those mentioned water interfaces has not been well investigated. In chapter 5, ion pairing of halide anions with K+ , Na+ and Cs+ is studied in bulk water and near to a model hydrophobic surface (graphite) to shed some more knowledge on ion specific phenomena. Small sized cations tend to pair strongly with small sized anions near hydrophobic interfaces compared with that in bulk water, whereas ion-pairing for salts with small(cation)-large(anion) combinations and large-large ion combinations is affected in a lesser extend. The solvent shared ion pair state is the ion-pairing mode that becomes more favorable owing to the higher ion-ion association near hydrophobic interfaces. Ion- ion association free energy profile is further decomposed into entropic and enthalpic components for better molecular level understanding. A positive entropic component in the free energy of the solvent shared and contact ion pair states near graphite surface is found alike in bulk solution. Hydrophobic association near graphite interface is also analyzed. The contact pair state becomes more favorable because of that the overall association is more feasible near hydrophobic interfaces. The electrostatic interaction between the surface charge from protein and the ion from ionic solution is another important aspect that also contributes significantly in peptide or protein stability. Negatively charged acetate group from glutamate and aspartate side-chains can bind specifically with different cations that contributes to ion specific protein-cation interaction. In chapter 6, the structural details and the free-energy, entropy and enthalpy of ion-pairing between acetate ion, a model charge group present in protein or peptide and cations, K+ , Na+ , Li+ are discussed. The different affinities of Na+ and K+ toward acetate anion is explained using an enthalpy-entropy reinforcement mechanism at solvent shared ion-pair (SIP) state which involves a water-mediated hydrogen bonding interaction between the oppositely charged ions. Finally in chapter 7, we conclude the thesis and provide some future outlook

Pedestrian Detection and Tracking in Video Surveillance System: Issues, Comprehensive Review, and Challenges

Pedestrian detection and monitoring in a surveillance system are critical for numerous utility areas which encompass unusual event detection, human gait, congestion or crowded vicinity evaluation, gender classification, fall detection in elderly humans, etc. Researchers’ primary focus is to develop surveillance system that can work in a dynamic environment, but there are major issues and challenges involved in designing such systems. These challenges occur at three different levels of pedestrian detection, viz. video acquisition, human detection, and its tracking. The challenges in acquiring video are, viz. illumination variation, abrupt motion, complex background, shadows, object deformation, etc. Human detection and tracking challenges are varied poses, occlusion, crowd density area tracking, etc. These results in lower recognition rate. A brief summary of surveillance system along with comparisons of pedestrian detection and tracking technique in video surveillance is presented in this chapter. The publicly available pedestrian benchmark databases as well as the future research directions on pedestrian detection have also been discussed

Establishment of an indirect organogenesis protocol for Eucalyptus grandis species and hybrids.

Thesis (M.Sc.)-University of KwaZulu-Natal, 2004.The prospect of integrating transgenic eucalypts with conventional breeding programmes is of value to the Plantation Forestry and Forest Products Industries. However, significant progress in this regard has still to be reported, one constraint is the lack of appropriate high yielding regeneration culture methods for clonal material. Such was the main aim of the present study. The strategy was to develop a suitable protocol using in vitro shoots of an E. grandis x E. urophy/la clone (GU185) and thereafter to test its applicability to other clones. Explants from greenhouseestablished cuttings provided the in vitro shoots, which were multiplied via axillary bud proliferation either on semi-solid medium or using a RIT A system. To determine the best conditions for callus and shoot regeneration, parameters such as vessels (petri dishes and tubes) and types and levels of plant growth regulators were tested. The best callus production (100%) and shoot regeneration (78.9 - 100% callus with shoots) for GU185 occurred on MS, 30 g rl sucrose, 4 g rl Gelrite, 5 mg rl IAA and 0.25 mg rl BAP. Parameters tested to identify the most suitable explants for indirect organogenesis were the age of parent plants, different systems to generate in vitro shoots, elongation status of explants, 1 sI and 2nd generation in vitro shoots and the use of hyperhydric shoots. Of these, the most suitable explants for indirect organogenesis were shoots from axillary bud multiplication of 3-month-old parent plants using the semi-solid system (33 shoots/dish). Up to 90% rooting was achieved on 1f4 MS (Murashige and Skoog, 1962), 15 g rl sucrose, 0.1 mg rl biotin, 0.1 mg rl calcium pantothenate, 4 g rl Gelrite and mA. The highest rooting was obtained when regenerated shoots were first multiplied and then placed on medium without plant growth regulators for one week, before transfer to root induction medium containing 0.1 - 0.5 mg rl mA. Acclimatization success was 95% when rooted shoots were placed in pots with a rooting mix (2 perlite: 1 coir) enclosed in plastic bags and the humidity was gradually reduced over four weeks. The developed indirect organogenesis protocol appeared to have a broad general application, although the tested clones exhibited a genotype-dependent response, with GU180, GUI77 and TAG31 producing fewer shoots (9, 6 and 7 shoots/dish) than ZG14 and GU185 (24 and 18 shoots/dish). Similarly high levels of rooting were obtained for TAG3l (93.8%) and ZG14 (90%) and for hardening-off (90.7% for TAG31 and 91.4% for ZG14)