Design of optimal correlation filters for hybrid vision systems

Research is underway at the NASA Johnson Space Center on the development of vision systems that recognize objects and estimate their position by processing their images. This is a crucial task in many space applications such as autonomous landing on Mars sites, satellite inspection and repair, and docking of space shuttle and space station. Currently available algorithms and hardware are too slow to be suitable for these tasks. Electronic digital hardware exhibits superior performance in computing and control; however, they take too much time to carry out important signal processing operations such as Fourier transformation of image data and calculation of correlation between two images. Fortunately, because of the inherent parallelism, optical devices can carry out these operations very fast, although they are not quite suitable for computation and control type operations. Hence, investigations are currently being conducted on the development of hybrid vision systems that utilize both optical techniques and digital processing jointly to carry out the object recognition tasks in real time. Algorithms for the design of optimal filters for use in hybrid vision systems were developed. Specifically, an algorithm was developed for the design of real-valued frequency plane correlation filters. Furthermore, research was also conducted on designing correlation filters optimal in the sense of providing maximum signal-to-nose ratio when noise is present in the detectors in the correlation plane. Algorithms were developed for the design of different types of optimal filters: complex filters, real-value filters, phase-only filters, ternary-valued filters, coupled filters. This report presents some of these algorithms in detail along with their derivations

The Roles of Membrane Rafts in CD32A-Mediated Phagocytosis

Membrane rafts are highly dynamic heterogeneous sterol- and sphingolipid-rich micro-domains on cell surfaces. They are generally believed to provide residency for cell surface molecules (e.g., adhesion and signaling molecules) and scaffolding to facilitate the functions of these molecules such as membrane trafficking, receptor transport, cell signaling, and endocytosis.
The governing, or overall hypothesis, for this project is that membrane rafts provide residency for Fc[gamma]RIIA (CD32A) on K562 cells, and that by doing so they provide a platform from which Fc[gamma]RIIA initiate or carry out their functions, which include migration, signaling, phagocytic synapse formation, and internalization of IgG opsonized targets.
Using immuno-fluorescent laser scanning confocal microscopy and reflection interference microscopy (RIM), we studied the spatial and temporal distributions of membrane rafts and surface receptors, signaling molecules, and cell organelles during the formation of phagocytic contact areas. K562 cells, which naturally express CD32A, a cell surface receptor for the Fc portion of Immuno-globulin G(IgG), was chosen as a model for neutrophils. An opsonized target was modeled using a glass supported lipid bilayer reconstituted with IgG. CD32A was found to cluster and co-localize with membrane rafts. Placing the K562 cells on the lipid bilayer triggered a process of contact area formation that includes binding between receptors and ligands, their recruitment to the contact area, a concurrent membrane raft movement to and concentration in the contact area, and transport of CD32A, IgG, and membrane rafts to the Golgi complex. Characterization of these processes was performed using agents known to disrupt detergent resistant membranes (DRMs), dissolve actin microfilaments, and inhibit myosin motor activity, which abolished the CD32A clusters and prevented the contact area formation. 
The relevance to phagocytosis of contact area formation between K562 cells and lipid bilayers was demonstrated using micro-beads coated with a lipid bilayer reconstituted with IgG as the opsonized target instead of the glass supported planar lipid bilayer. Disruption of membrane rafts, salvation of the actin cytoskeleton, and inhibition of myosin II activity were found to inhibit phagocytosis.
These data suggest membrane rafts play several important roles in CD32A mediated phagocytosis including pre-clustering CD32A, transport of CD32A to the phagocytic cup, and transport of the opsonized target towards the Golgi complex. Here we have provided evidence that membrane rafts serve as platforms which are used to cluster CD32A and transport CD32A along the actin cytoskeleton to the site of phagocytic synapse formation thus allowing for the quick assembly of a phagocytic synapse.
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MCSF drives regulatory DC development in stromal co-cultures supporting hematopoiesis

Background: Splenic stroma overlaid with hematopoietic progenitors supports in vitro hematopoiesis with production of dendritic-like cells. Co-cultures of murine lineage-depleted bone marrow over the 5G3 stromal line produce two populations of cells, characterised as CD11b+CD11c+MHC-II− dendritic-like ‘L-DC’, and CD11b+CD11c+ MHC-II+ cells, resembling conventional dendritic cells (cDC). To date, the functional capacity of these two subsets has not been clearly distinguished. Results: Here we show both the L-DC and cDC-like subsets can be activated and induce proliferation of OT-I CD8+ T cells, being strong inducers of IL-2 and IFN-γ production. Both subsets lack ability to induce proliferation of OT-II CD4+ T cells. The cDC-like population is shown here to resemble regulatory DC in that they induce FoxP3 expression and IL10 production in OT-II CD4+ T cells, in line with their function as regulatory DC. L-DC did not activate or induce the proliferation of CD4+ T cells and did not induce FoxP3 expression in CD4+ T cells. L-DC can be distinguished from cDClike cells through their superior endocytic capacity and expression of 4-1BBL, F4/80 and Sirp-α. A comparison of gene expression by the two subsets was consistent with L-DC having an activated or immunostimulatory DC phenotype, while cDC-like cells reflect myeloid dendritic cells with inflammatory and suppressive properties, also consistent with functional characteristics as regulatory DC. When a Transwell membrane was used to prevent hematopoietic cell contact with stroma, only cDC-like cells and not L-DC were produced, and cell production was dependent on M-CSF production by stroma. Conclusion: Co-cultures of hematopoietic progenitors over splenic stroma produce two distinct subsets of dendritic-like cells. These are here distinguished phenotypically and through gene expression differences. While both resemble DC, there are functionally distinct. L-DC activate CD8+ but not CD4+ T cells, while the cDC-like population induce regulatory T cells, so reflecting regulatory DC. The latter can be enriched through Transwell co-cultures with cell production dependent on M-CSF. Keywords: Hematopoiesis, Dendritic cell, Regulatory dendritic cells, Regulatory T cellsThis work was supported by project grant #585443 to HO from the National Health and Medical Research Council of Australia. SP was supported by a graduate scholarship from the Royal Thai Government. PP was supported by an Australian National University Graduate Scholarship

Bisphosphonate-induced periprosthetic fracture: a cause of painful total hip arthroplasty

Background. Cases have been reported in the literature of periprosthetic fractures associated with the use of bisphosphonates occurring in the long term following a Total Hip Replacement (THR). We report an interesting case of periprosthetic fracture secondary to bisphosphonate use only a few months after a THR. Case Report. A 72-year-old lady (on bisphosphonates for 10 years) underwent a THR for osteoarthritis. She was pain-free in the first four months postoperatively. Thereafter, she developed spontaneous onset of pain in the lateral aspect of her thigh and groin and found it difficult to weight-bear. X-rays and blood tests were unremarkable. An ultrasound and MRI scan showed no evidence of effusion/collection or periprosthetic fracture. A radionuclide bone scan showed an abnormal appearance of the right femoral shaft. A subsequent CT scan showed an oblique vertical split on the anterior surface of the upper right femoral shaft. This stress fracture was managed nonoperatively with protected weight bearing. She has progressed well with good clinical and radiological signs of fracture healing. Conclusion. This case is an important addition to our knowledge that bisphosphonate-induced periprosthetic stress fractures can be a cause of hip pain only a few months following a THR.</p

Port security in a developing country – pre and post 9/11 terrorist attacks: a case study on Port Klang in Malaysia

The terrorist attacks on 11 September 2001 on the World Trade Centre and Pentagon in the United States widely known as 9/11 undeniably produced a profound impact on a multitude sectors across the globe. The events became a turning point in the treatment of maritime security establishing a “before” and after” dividing line. One element that emerged in response to that attack was the change of attitude to security. This change, led to changes in behaviour and practices since it prompted a raft of measures, rules, and regulations to prevent such occurrences in the future. This thesis examines how security in the maritime sphere in respect of ports was given a new impetus by virtue of their inherent weaknesses as a potential target. In the past, port security was primarily focused on cargo theft and pilferage as well as denying access to those seeking to enter the country to improve their political or economic condition or to engage in smuggling activities. While the international regulation of shipping had increased substantially through the efforts of the International Maritime Organisation (IMO) in the second half of the 20th century, ports had remained largely unaffected by this regulation. However, the 9/11 changed this situation. As the main focus turned towards dual objectives: to secure ports from any kinds of unlawful acts and concurrently fulfil the international security requirements, implementing and complying with a host of security regimes imposed by a range of parties was seen by some commentators as a particular challenge for the developing nations, due to higher costs and the implications for port policy and administration. This study examines this generalisation using the Port Klang and Malaysian port system as a case study. It analyses security measures and management before and after 9/11, considering the impact not only of international regulations, especially the International Ship and Port Facility Security (ISPS) Code, but also of bi-lateral security measures required by the United States as a trading partner and regional organisations. Its findings are based on in-depth interviews conducted with the key Malaysian governmental and private stakeholders, supplemented by other primary and secondary sources. The study concludes that, partly as a result of previous colonial and post-colonial anti-terrorist measures, Malaysia generally had a well managed port security system prior to 9/11. This meant that though some minor internal and external problems were identified, Malaysia managed to handle effectively the post 9/11 port security regimes with minimal cost implications. Any presumption that, as a developing country, it would have problems with implementation proved to be unfounded

An experimental and numerical study of evaporation enhancement and combustion in porous media.

The results showed that the pressure drop across the porous media increased as the coflow air velocity, temperature, and linear pore density of the medium were increased. The measured and predicted surface temperatures of evaporation and combustion porous media showed that the temperature distribution was uniform within +/- 25 K and 50 K, respectively. The droplet Sauter mean diameter data revealed that the spray core region contained droplets with lower diameter, and the droplet diameter increased radially outward. A heat feedback rate to the evaporation porous medium section of about 1% of the average heat release in the combustion section was needed to completely vaporize the kerosene fuel. The vapor concentration level downstream of evaporation porous medium with 1% combustion heat release feedback was 63% higher than that with no heat feedback.Our results also suggest that the use of porous media in combustors allows operation at a lower coflow air temperature or with a shorter evaporation section. The porous-medium-burner concepts developed in this dissertation can be employed in many practical liquid combustion systems such as gas turbine combustors, air-heating systems, industrial burners, porous chemical reactors, heat recovery systems, and hybrid burners for bio-fuels.Stable spray flames were established both inside (referred to as interior flames) and on the downstream exit surface (surface flames) of the combustion porous medium. The equivalence ratio at flame extinction in each mode was determined. The extinction equivalence ratio decreased with a decrease in coflow air velocity. A nominal value of Damkohler number of 5.0 was required to initiate the interior combustion mode. As Damkohler number was increased, the extinction equivalence ratio decreased (i.e., extending the fuel lean operation). The axial temperature profiles in evaporation and combustion porous media were measured. Also measured were the radiative heat release from porous medium downstream exit surface, and pollutant emissions of carbon monoxide and nitric oxide. The results demonstrate the benefits of porous medium in making NO emission somewhat insensitive to operating parameters such as equivalence ratio and location of injector.Blocks of open-cell, silicon carbide coated, carbon-carbon ceramic foam of bulk cross section 4 x 4 cm and thickness of 2.5 cm were used as porous medium sections for liquid evaporation and subsequent combustion. Liquid fuel (kerosene, n-heptane, and methanol) was sprayed into a co-flowing, preheated (350--490 K) air environment using an air-blast atomizer, and the spray subsequently entered the porous medium. In controlled evaporation studies, combustion heat feedback to evaporation porous medium was simulated with a resistive heating mechanism. The minimum heat feedback rate required for complete vaporization of liquid and the vapor concentration profiles downstream of evaporation porous medium were measured. The stable operating regimes of spray flames in the combustion porous medium were determined and a general understanding of flame extinction in porous media was developed using a Damkohler number analysis.A two-energy equation model was developed to study the evaporation enhancement of liquid spray in the porous media. Combustion in the porous media was simulated by using a uniform volumetric heat source in the porous region. The solid and gas phase equations were coupled using a volumetric heat transfer coefficient. The computer simulations were performed with a commercial code, Fluent(TM) 6.0.Combustion of gaseous fuels in porous media improves combustion performance and reduces pollutant emissions by transferring combustion heat upstream via conduction and radiation to preheat reactants. Such heat feedback may be beneficially exploited to enhance vaporization of a liquid sprayed upstream of the porous medium, in addition to improving combustion performance. This dissertation presents an experimental and computational study of evaporation enhancement and combustion of liquid spray aided by porous media

Development of kisspeptin-GnRH neural circuit in utero and mapping of GnRH receptor neurons in mice brain

'Gonadotropin releasing hormone (GnRH)'-Neurone repräsentieren die gemeinsame ZNS-Endstrecke zur hormonalen Kontrolle der Keimdrüsen. Dabei unterliegt die GnRH-Freisetzung einer Feedback-Regulation durch das gonadale Steroidhormon Östrogen. GnRH-Neurone exprimieren selbst allerdings nicht Östrogen-Rezeptor-alpha (ER), was nahelegt, dass das Feedback-Signal über einen vorgeschalteten Steroid-sensitiven Signalweg auf GnRH-Neurone übertragen wird. Tatsächlich fungieren 'Kisspeptin'-Neurone als Upstream-Regulator der GnRH-Freisetzung und dienen als Angriffspunkt für Steroidhormone in der Regulation der GnRH-Sekretion. GnRH-Neurone exprimieren den Kisspeptin-Rezeptor GPR54. Kisspeptin-Neurone sind im Gehirn vor allem im Nucleus arcuatus (ARC) und im anterolateralen Nucleus paraventricularis (AVPV) lokalisiert. Kisspeptin-Neurone projizieren in die mediane Eminenz und auf GnRH-Neurone der prä-optischen Region. Kisspeptin bindet an GPR54 und stimuliert GnRH-Neurone der prä-optischen Region zur GnRH-Freisetzung in die Zirkulation. In der vorliegenden Arbeit wurde das genaue raumzeitliche Expressionsmuster der dem GnRH-Neuron vor- und nachgeschaltetem Neuronensysteme, des 'Kisspeptin'-Systems und des GnRH-exprimierenden Systems, bestimmt. Dazu wurde zunächst das Einsetzen der Expression von Kisspeptin und seinem Rezeptor GPR54 in männlichen KissIC/eR26-GFP-Embryonen sowie in männlichen GPIC/eR26-GFP-Embryonen untersucht. Kisspeptin und GPR54 erschienen gleichzeitig am Embryonaltag E13.5. Während der ganzen embryonalen Hirnentwicklung wurde Kisspeptin nur im ARC des Hypothalamus gefunden. Hingegen blieb die Expression von GPR54 auf GnRH-Neurone beschränkt. Die detailierte Analyse zeigt jedoch, dass das GPR54-Expressionsmuster unabhängig von der Lage der GnRH-Neuronen war. Zur Bestimmung des Zeitpunkts, an dem Kisspeptin-Neurone sensitiv gegenüber Sexualsteroiden werden, wurde die Expression von Östrogen-Rezeptor ER und von Androgen-Rezeptor (AR) in ARC Kisspeptin-Neuronen untersucht. Es stellte sich heraus, dass ER und AR-positive Neurone die embryonale Hirnregion markieren, in der sich Kisspeptin-Neurone entwickeln. Trans-synaptisches Tracing zeigte schließlich, dass im männlichen embryonalen Mäusegehirn Kisspeptin-Neurone des ARC mit dem GnRH-Neuronensystem kommunizieren. Die Verbindung zwischen ARC-Kisspeptin-Neuronen und GnRH-Neuronen ist unabhängig von der Lage der Neurone im männlichen embryonalen Mäusegehirn. Diese Beobachtung legt den Schluß nahe, dass im Gegensatz zum adulten Gehirn, in dem Kisspeptin-Neurone eine geschlechtsspezifische Verteilung aufweisen, Beginn und Entwicklung des Kisspeptin-GPR54-Systems im männlichen embryonalen Mäusegehirn eher dem weiblichen Mäusegehirn ähneln und dass der Sexualdimorphismus erst später in der Entwicklung entsteht. Es folgte die Untersuchung des Downstream-Targets, dem Gonadotropin releasing hormone receptor (GnRHR)-Neurons. In der Hypophyse triggert GnRH-Rezeptorbindung die Synthese und Freisetzung von Luteinisierungshormon (LH) und von follikelstimulierendem Hormon (FSH). Die Rolle von GnRHR in den gonadotropen Zellen der Hypophyse ist bekannt, aber die Funktion der GnRHR-Neurone im Gehirn ist noch nicht vollständig geklärt. Zur Bearbeitung dieser Frage wurde die Verteilung der GnRHR-Neurone im embryonalen Gehirn von weiblichen GnRHR/eR26-GFP-Mäuseembryonen kartiert. Es stellte sich heraus, dass ihre Anzahl signifikant im Lauf der Entwicklung ansteigt. Die GnRHR-Neuronen reicherten sich in der olfaktorischen Hirnregion und in Sexualzentren wie der medialen Amygdala (MeA), der medialen prä-optischen Region (MPA), dem ventromedialen Hypothalamus (VMH) und der peri-aquaeduktalen grauen Substanz (PAG) an. Die GnRHR-Neuronen der olfaktorischen Regionen und Sexualzentren erwiesen sich als sensitiv gegenüber Sexualsteroiden. Erstmalig konnte die olfaktorische Stimulation von GnRHR-exprierenden Neuronen gezeigt werden. Die Ergebnisse der vorliegende Untersuchung liefern Einblicke in die Entwicklung des Kisspeptin-GPR54-Systems und können zum besseren Verständnis von Störungen der Geschlechtsentwicklung wie dem hypogonadotrophen Hypogonadismus oder der Pubertas praecox beitragen. Die anatomische Kartierung der GnRHR-Neurone im Gehirn beleuchtet die Rolle von GnRH-Signalwegs in der Säugetier-Hypothalamus/Hypophysen/Gonaden-Achse.Gonadotropin releasing hormone (GnRH) neurons are the final common output pathway by which brain controls reproduction. Gonadal steroid hormone, estrogen regulates GnRH release by feedback signaling. Interestingly, GnRH neurons do not express estrogen receptors (ER suggesting that a steroid sensitive pathway might mediate these effects on GnRH neuron. Kisspeptin, a key upstream regulator of GnRH secretion serves as a target for steroid hormone in the control of GnRH secretion. GnRH neurons express kisspeptin receptor, GPR54. Kisspeptin neurons are primarily located in two major locations of the hypothalamus, the arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV). Kisspeptin neurons project to GnRH neurons located in the preoptic area (and to the median eminence). Kisspeptin binds to GPR54 to stimulate GnRH neuron in the preoptic area to release GnRH into the circulation. The goal of this study is to determine the precise spatio-temporal expression pattern of the upstream and the downstream target of GnRH neuron, Kisspeptin system and GnRHR expressing neurons respectively. I examined the onset of kisspeptin and its receptor, GPR54 in the KissIC/eR26-GFP and GPIC/eR26-GFP male mouse embryo respectively. Interestingly expression of Kisspeptin and its receptor GPR54 initiates at the same time (E13.5). Throughout the embryonic brain development kisspeptin neurons remain restricted to the ARC of the hypothalamus whereas GPR54 expression is restricted to the GnRH neuron. Detailed analysis revealed that the GPR54 expression is independent of the location of the GnRH neuron. Next I analyzed when kisspeptin neurons becomes sensitive to gonadal steroid hormones. I investigated the expression of estrogen receptor alpha (ER) and androgen receptor (AR) in the ARC kisspeptin neuron. I observed that ERand AR positive neurons marks the birthplace of kisspeptin neuron in the embryonic brain. Transsynaptic tracing in the embryonic mouse brain revealed that ARC kisspeptin neurons communicate with GnRH neurons in utero. The connectivity between ARC kisspeptin neurons and GnRH neurons is independent of the location of the GnRH neurons in the embryonic male mouse brain. These observations suggests that in contrast to the adult brain where kisspeptin neurons are present in sexually dimorphic manner, onset and the development of Kisspeptin-GPR54 system in embryonic male brain is highly similar to female brain and sexual dimorphism arises later in development. Next, I investigated the downstream target of GnRH neuron, gonadotropin releasing hormone receptor (GnRHR) expressing neurons. GnRH binds to its receptor in pituitary to trigger the synthesis and release of luteinizing hormone (LH) and follicle stimulating hormone (FSH). The role of GnRHR in pituitary gonadotropes is well understood but the function of GnRHR neurons in the brain is not well established. Using GnRHR/eR26-GFP mouse I mapped the distribution of GnRHR neurons in the female brain. I observed that the GnRHR neurons are concentrated in olfactory processing areas and reproductive centers in the brain such as medial amygdala (MeA), medial preoptic area (MPA), ventromedial hypothalamus (VMH) and periaqueductal grey (PAG). I found that the number of GnRHR neurons significantly increases across developmental stage I also observed that GnRHR neurons in olfactory and reproductive centers are sensitive to steroid hormones. For the first time I also identified that GnRHR expressing neurons are activated upon olfactory stimulation. Taken together, the present study provides insight into the (I) development of kisspeptin-GPR54 system which will help to better understand reproductive disorders such as hypogonadotropic hypogonadism and precocious puberty (II) detailed anatomical mapping of GnRHR neurons in the brain will help in understanding the role of GnRH signaling in the mammalian brain and its effect on reproductive axi

Development of a picking and dropping mechanism for protray grown vegetable seedlings

In India, manual transplanting of vegetable seedlings was the commonly adopted method for raising vegetable crops, but it is laborious, time-consuming and costly. Therefore, mechanical transplanters are developed to overcome the problems in manual transplanting. The present work was to develop multiple seedlings picking and transferring mechanism for protray grown vegetable seedlings. Tomato (Solanum lycopersicum), chilli (Capsicum annuum) and brinjal (Solanum melongena) seedlings were raised in portrays with coir pith as a growth media and used for transplanting operation. The mechanism was to pick seven numbers of seedlings in one row at a time and transfer them into lateral conveying system, which could deliver the seedlings one by one on to the ground at regular interval. Programmable Logic Controller was used to controlling entire operations of seedlings picking and dropping. At the time of evaluation, a totally 196 number of seedlings were used with 98 cell protray. From the test results, the success rate of 89.28 per cent, missing seedling of 3.57 per cent, damaged seedling of 4.08 per cent, seedling delivering failure of 3.06 per cent were recorded for tomato seedlings. Similarly, in chilli and brinjal the success rate of 95.40 and 91.83 per cent, the missing seedling of 2.04 and 2.55 per cent, damaged seedling of 1.53 and 3.06 per cent and seedling delivering failure of 1.02 and 2.55 per cent respectively were observed. Transplanting frequency of developed mechanism was 2520 seedlings h-1.   As a whole, this work was able to develop a working model of vegetable seedling transplanting mechanism, which can eject seven seedlings at a time from portray cell and transfer them into the slotted conveyor.