Thrust chamber material technology program

This report covers work performed at Pratt & Whitney on development of copper-based materials for long-life, reusable, regeneratively cooled rocket engine thrust chambers. The program approached the goal of enhanced cyclic life through the application of rapid solidification to alloy development, to introduce fine dispersions to strengthen and stabilize the alloys at elevated temperatures. After screening of alloy systems, copper-based alloys containing Cr, Co, Hf, Ag, Ti, and Zr were processed by rapid-solidification atomization in bulk quantities. Those bulk alloys showing the most promise were characterized by tensile testing, thermal conductivity testing, and elevated-temperature, low-cycle fatigue (LFC) testing. Characterization indicated that Cu- 1.1 percent Hf exhibited the greatest potential as an improved-life thrust chamber material, exhibiting LCF life about four times that of NASA-Z. Other alloys (Cu- 0.6 percent Zr, and Cu- 0.6 percent Zr- 1.0 percent Cr) exhibited promise for use in this application, but needed more development work to balance properties

An exploration of gastropod-borne parasites with a focus on intestinal schistosomiasis in Biomphalaria snails inhabiting the Great African Lakes

Gastropod-borne parasitic diseases are a significant concern for public health all over the world, but particularly in developing countries. Many species of terrestrial and freshwater gastropods serve as the intermediate host for various parasites with medical and/or veterinary significance. One such example is the intravascular trematode species, Schistosoma mansoni (Digenea: Schistosomatidae), which is the leading cause of intestinal schistosomiasis globally. The obligatory intermediate host of S. mansoni is the freshwater snail genus, Biomphalaria (Gastropoda: Planorbidae). The vast majority of intestinal schistosomiasis cases occur in sub-Saharan regions of Africa, with countries in East Africa suffering from a high prevalence of S. mansoni in and around the Great African Lakes. The hyper-endemic nature of intestinal schistosomiasis at Lake Albert and Lake Victoria is a significant public health concern. In addition to trematodes, other gastropod-borne parasites such aslungworms (Strongylida) are common causes of disease in humans and companion animals. Unlike digenetic trematodes, lungworms do not specialise in their choice of obligatory intermediate host and can use numerous species of both terrestrial and freshwater gastropods to infect their definitive host, typically through consumption. The parasitic nematode genus, Angiostrongylus(Chromadorea: Angiostrongylidae) for example, contains species that cause angiostrongyliasis in humans (An. cantonensis) and dogs (An. vasorum). Despite being endemic to tropical regions, an An. cantonensis infection was recently reported in France as the first ever autochthonous human case of angiostrongyliasis in mainland Europe. Conversely, An. vasorum is found globally. In the UK, it is most prevalent in Southern England and Southern Wales, though there have been reports of the parasite as far north as Scotland. Chapter 3 “Comparing shell size and shape with canonical variate analysis of sympatric Biomphalaria species within Lake Albert and Lake Victoria” utilises landmark-based geometric morphometric techniques to differentiate the conchological characteristics of four Biomphalaria species inhabiting the Great African Lakes of Uganda. The study found that it was possible to accurately discriminate and identify all Biomphalaria species present at the Great African Lakes in Uganda (B. choanomphala, B. pfeifferi, B. stanleyi and B. sudanica) using a canonical variate analysis (CVA) of the apical and apertural angles of the shell. Chapter 4 “Schistosoma mansoni infection in Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria” uses PCR-based molecular infection detection methods to quantify the prevalence of S. mansoni infection among the Biomphalaria species present at the Ugandan shorelines of Lake Albert (B. pfeifferi, B. stanleyi and B. sudanica) and Lake Victoria (B. choanomphala). It also measures prevalence of infection for each of the wet and dry seasons over a two year period for both lakes. The study found that the mean prevalence of S. mansoni infection was higher at Lake Albert (12.5%) than Lake Victoria (5%), with B. stanleyi (15%) having the highest mean infection prevalence of the four species tested. In addition, the wet seasons at both lakes had a higher mean prevalence of infection than the dry seasons, though this difference was not statistically significant. Chapter 5 “Schistosoma mansoni infection and population genetic structure of Biomphalaria choanomphala snails in Lake Victoria” uses PCR-based molecular infection detection methods to quantify the prevalence of S. mansoni infection across the Kenyan, Tanzanian and Ugandan shorelines of Lake Victoria. Additionally, several abiotic (temperature, pH, physiochemical etc.) and biotic (snail genetic diversity) factors were measured to investigate which factors are involved in schistosomiasis transmission. The study found the mean prevalence of S. mansoni infection among B. choanomphala snails across Lake Victoria was 9.3%, with the Tanzanian shoreline having the highest prevalence, followed by the Ugandan and Kenyan shorelines. There was a significant positive relationship with infection prevalence and B. choanomphala abundance, calcium, and magnesium concentrations. Conversely, there was a significant negative correlation between infection prevalence and increasing water alkalinity. Lastly, populations of B. choanomphala where S. mansoni infection was present had a higher mean haplotype diversity score and less private haplotypes than populations without infection present. Chapter 6 “Nematodes and trematodes associated with terrestrial gastropods in Nottingham, England” implements traditional parasitological and molecular identification techniques to survey the terrestrial gastropod populations in and around the city of Nottingham, with the intention of finding medical (or veterinary) important parasites. The study found the mean infection prevalence of terrestrial gastropods was 28.3%, with slugs and snails having similar prevalence of infection. Of the gastropod-borne parasites extracted, seven nematode species and four trematode species were identified. No medical or veterinary important parasites were discovered in or around the city of Nottingham

An exploration of gastropod-borne parasites with a focus on intestinal schistosomiasis in Biomphalaria snails inhabiting the Great African Lakes

Gastropod-borne parasitic diseases are a significant concern for public health all over the world, but particularly in developing countries. Many species of terrestrial and freshwater gastropods serve as the intermediate host for various parasites with medical and/or veterinary significance. One such example is the intravascular trematode species, Schistosoma mansoni (Digenea: Schistosomatidae), which is the leading cause of intestinal schistosomiasis globally. The obligatory intermediate host of S. mansoni is the freshwater snail genus, Biomphalaria (Gastropoda: Planorbidae). The vast majority of intestinal schistosomiasis cases occur in sub-Saharan regions of Africa, with countries in East Africa suffering from a high prevalence of S. mansoni in and around the Great African Lakes. The hyper-endemic nature of intestinal schistosomiasis at Lake Albert and Lake Victoria is a significant public health concern. In addition to trematodes, other gastropod-borne parasites such aslungworms (Strongylida) are common causes of disease in humans and companion animals. Unlike digenetic trematodes, lungworms do not specialise in their choice of obligatory intermediate host and can use numerous species of both terrestrial and freshwater gastropods to infect their definitive host, typically through consumption. The parasitic nematode genus, Angiostrongylus(Chromadorea: Angiostrongylidae) for example, contains species that cause angiostrongyliasis in humans (An. cantonensis) and dogs (An. vasorum). Despite being endemic to tropical regions, an An. cantonensis infection was recently reported in France as the first ever autochthonous human case of angiostrongyliasis in mainland Europe. Conversely, An. vasorum is found globally. In the UK, it is most prevalent in Southern England and Southern Wales, though there have been reports of the parasite as far north as Scotland. Chapter 3 “Comparing shell size and shape with canonical variate analysis of sympatric Biomphalaria species within Lake Albert and Lake Victoria” utilises landmark-based geometric morphometric techniques to differentiate the conchological characteristics of four Biomphalaria species inhabiting the Great African Lakes of Uganda. The study found that it was possible to accurately discriminate and identify all Biomphalaria species present at the Great African Lakes in Uganda (B. choanomphala, B. pfeifferi, B. stanleyi and B. sudanica) using a canonical variate analysis (CVA) of the apical and apertural angles of the shell. Chapter 4 “Schistosoma mansoni infection in Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria” uses PCR-based molecular infection detection methods to quantify the prevalence of S. mansoni infection among the Biomphalaria species present at the Ugandan shorelines of Lake Albert (B. pfeifferi, B. stanleyi and B. sudanica) and Lake Victoria (B. choanomphala). It also measures prevalence of infection for each of the wet and dry seasons over a two year period for both lakes. The study found that the mean prevalence of S. mansoni infection was higher at Lake Albert (12.5%) than Lake Victoria (5%), with B. stanleyi (15%) having the highest mean infection prevalence of the four species tested. In addition, the wet seasons at both lakes had a higher mean prevalence of infection than the dry seasons, though this difference was not statistically significant. Chapter 5 “Schistosoma mansoni infection and population genetic structure of Biomphalaria choanomphala snails in Lake Victoria” uses PCR-based molecular infection detection methods to quantify the prevalence of S. mansoni infection across the Kenyan, Tanzanian and Ugandan shorelines of Lake Victoria. Additionally, several abiotic (temperature, pH, physiochemical etc.) and biotic (snail genetic diversity) factors were measured to investigate which factors are involved in schistosomiasis transmission. The study found the mean prevalence of S. mansoni infection among B. choanomphala snails across Lake Victoria was 9.3%, with the Tanzanian shoreline having the highest prevalence, followed by the Ugandan and Kenyan shorelines. There was a significant positive relationship with infection prevalence and B. choanomphala abundance, calcium, and magnesium concentrations. Conversely, there was a significant negative correlation between infection prevalence and increasing water alkalinity. Lastly, populations of B. choanomphala where S. mansoni infection was present had a higher mean haplotype diversity score and less private haplotypes than populations without infection present. Chapter 6 “Nematodes and trematodes associated with terrestrial gastropods in Nottingham, England” implements traditional parasitological and molecular identification techniques to survey the terrestrial gastropod populations in and around the city of Nottingham, with the intention of finding medical (or veterinary) important parasites. The study found the mean infection prevalence of terrestrial gastropods was 28.3%, with slugs and snails having similar prevalence of infection. Of the gastropod-borne parasites extracted, seven nematode species and four trematode species were identified. No medical or veterinary important parasites were discovered in or around the city of Nottingham

Live Migration Downtime Analysis of a VNF Guest for a Proposed Optical FMC Network Architecture

Fixed Mobile Convergence (FMC) implies use of a shared optical fronthaul network infrastructure able to carry transparently both fixed and mobile traffic including Wi-Fi, Mobile and fixed Ethernet. Network Function Virtualization (NFV) is a main enabler for FMC using a shared infrastructure for fixed and mobile gateways. Live migration, a virtualization key-feature, offers load-balancing, increased energy efficiency, application elasticity and other worthy advantages. This paper presents the evaluation of migrating a VNF over an FMC infrastructure. Our results show that, performing a livemigration over a dedicated connection yielded zero downtime and met a benchmark delay. The following scenario, where the ongoing connection is re-routed on a different optical path, shows the successful completion of the migration with an increase in delay of 2.4 seconds (22% higher than the benchmark) and only 2.1 seconds downtime Fixed Mobile Convergence (FMC) implies use of a shared optical fronthaul network infrastructure able to carry transparently both fixed and mobile traffic including Wi-Fi, Mobile and fixed Ethernet. Network Function Virtualization (NFV) is a main enabler for FMC using a shared infrastructure for fixed and mobile gateways. Live migration, a virtualization key-feature, offers load-balancing, increased energy efficiency, application elasticity and other worthy advantages. This paper presents the evaluation of migrating a VNF over an FMC infrastructure. Our results show that, performing a live migration over a dedicated connection yielded zero downtime and met a benchmark delay. The following scenario, where the ongoing connection is re-routed on a different optical path, shows the successful completion of the migration with an increase in delay of 2.4 seconds (22% higher than the benchmark) and only 2.1 seconds downtime

Short‐term effects of smoking marijuana on balance in patients with multiple sclerosis and normal volunteers

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110106/1/cptclpt199433.pd

UVB radiation induced effects on cells studied by FTIR spectroscopy

We have made a preliminary analysis of the results about the eVects on tumoral cell line (lymphoid T cell line Jurkat) induced by UVB radiation (dose of 310 mJ/cm^2) with and without a vegetable mixture. In the present study, we have used two techniques: Fourier transform infrared spectroscopy (FTIR) and flow cytometry. FTIR spectroscopy has the potential to provide the identiWcation of the vibrational modes of some of the major compounds (lipid, proteins and nucleic acids) without being invasive in the biomaterials. The second technique has allowed us to perform measurements of cytotoxicity and to assess the percentage of apoptosis. We already studied the induction of apoptotic process in the same cell line by UVB radiation; in particular, we looked for correspondences and correlations between FTIR spetroscopy and flow cytometry data finding three highly probable spectroscopic markers of apoptosis (Pozzi et al. in Radiat Res 168:698-705, 2007). In the present work, the results have shown significant changes in the absorbance and spectral pattern in the wavenumber protein and nucleic acids regions after the treatments

Differentiation of Bulinus senegalensis and Bulinus forskalii Snails in West Africa Using Morphometric Analysis

Purpose: Accurate identification of medically important intermediate host and vector species is crucial for understanding disease transmission and control. Identifying Bulinus snails which act as intermediate host species for the transmission of schistosomiasis is typically undertaken using conchological and genital morphology as well as molecular methods. Methods: Here, a landmark-based morphometric analysis of shell morphology was undertaken to determine its utility to distinguish the closely related and morphologically similar sister species Bulinus senegalensis and Bulinus forskalii. The method was developed to increase the accuracy of conchological morphology methods to identify Bulinus species in the field. Both species are found in West Africa, but only B. senegalensis is implicated in the transmission of urogenital schistosomiasis. Results: We found when scaled down to the same length, 3-whorl and 4-whorl (juvenile) B. senegalensis shells had a longer spire, narrower body whorl and shorter aperture than B. forskalii. In contrast, 5-whorl (adult) B. senegalensis had a shorter spire, but still had a shorter aperture and narrower body whorl than B. forskalii. Canonical Variate Analysis (CVA) showed minimal overlap between B. senegalensis and B. forskalii for 3-whorl and 4-whorl shells, with a clear separation for 5-whorl shells. Overall, B. senegalensis had a consistently shorter aperture size and narrower body whorl than B. forskalii for all development stages. Spire length was variable depending on the stage of development, with 3-whorl and 4-whorl shells having the opposite trends of adult shells. Conclusions: Our study demonstrates the applicability of landmark-based morphometrics in distinguishing the medically important, Bulinus senegalensis from its morphologically similar sister species, Bulinus forskalii. We recommend using measurements based on spire length, penultimate whorl length, body whorl width and aperture size to differentiate B. senegalensis and B. forskalii, when used with the appropriate information for each shell’s development stage

Seasonal patterns of Schistosoma mansoni infection within Biomphalaria snails at the Ugandan shorelines of Lake Albert and Lake Victoria

Intestinal schistosomiasis is hyperendemic in many sub-Saharan African countries. In Uganda, it is endemic at both Lake Albert (LA) and Lake Victoria (LV) and caused by S. mansoni that uses Biomphalaria snails as obligatory intermediate snail hosts. To shed light on local patterns of infection, we utilised two PCR-based methods to detect S. mansoni within Biomphalaria spp. as collected at the Ugandan shorelines of Lake Albert and Lake Victoria from 2009–2010. Overall, at our Lake Albert sites, the mean infection prevalence was 12.5% (15 of 120 snails), while at our Lake Victoria sites the prevalence was 5% (3 of 60 snails). At our Lake Albert sites, the highest infection prevalence of 13.3% (8 of 60 snails) was at Walukuba, while at our Lake Victoria sites, the highest infection prevalence of 10% (2 of 20 snails) was at Lwanika. Three species of Biomphalaria, B. pfeifferi, B. stanleyi and B. sudanica, were identified at our Lake Albert collection sites, while only a single species, B. choanomphala, was identified at our Lake Victoria collection sites. Biomphalaria stanleyi (2 of 20 snails; 15%) had the highest infection prevalence, followed by B. sudanica (5 of 60 snails; 13.3%), B. pfeifferi (4 of 40 snails; 10%) and B. choanomphala (3 of 60 snails; 5%). Of the Biomphalaria species identified, B. choanomphala had the highest haplotype (gene) diversity score, followed by B. stanleyi, B. sudanica and B. pfeifferi. Sites with a higher mean prevalence of S. mansoni infection had higher intra-species haplotype diversity scores than sites with a lower mean prevalence. The wet seasons (LA: 13.3%; LV: 8.7%) had a consistently higher mean infection prevalence of S. mansoni than the dry seasons (LA: 9.5%; LV: 5%) for all species and all sites tested at both Lake Albert (n = 480) and Lake Victoria (n = 320), though the difference was not statistically significant