Low cycle fatigue of MAR-M 200 single crystals at 760 and 870 deg C

Fully reversed low cycle fatigue tests were conducted on single crystals of the nickel-base superalloys Mar-M 200 at 760 C and 870 C. At 760 C, planar slip (octahedral) lead to orientation-dependent strain hardening and cyclic lives. Multiple slip crystals strain hardened the most, resulting in relatively high stress ranges and low lives. Single slip crystals strain hardened the least, resulting in relatively low stress ranges and higher lives. A preferential crack initiation site which was related to slip plane geometry was observed in single slip orientated crystals. At 870 C, the trends were quite different, and the slip character was much more homogeneous. As the tensile axis orientation deviated from 001 , the stress ranges increased and the cyclic lives decreased. Two possible mechanisms were proposed to explain the behavior: one is based on Takeuchi and Kuramoto's cube cross-slip model, and the other is based on orientation-dependent creep rates

Analysis of Herpes Simplex Virus-Specific T Cells in the Murine Female Genital Tract Following Genital Infection with Herpes Simplex Virus Type 2

AbstractA murine model of genital infection with a thymidine kinase-deficient (tk-) strain of herpes simplex virus type 2 (HSV-2) was utilized to examine the development of the local T cell response in the genital mucosa and draining genital lymph nodes (gLN). HSV-specific cytokine-secreting T cells were detected in the gLN 4 days postintravaginal inoculation but not in the urogenital tract or spleen until 5 days postinoculation, suggesting the cellular immune response originates in the gLN. More CD4+ than CD8+ gLN T cells were detected by flow cytometric analysis following primary vaginal inoculation and the majority of HSV-specific gLN T cells detected by ELISPOT were CD4+ and Th1-like based on secretion of IFNγ and not IL-4 or IL-5. A similar population of HSV-specific memory T cells persisted in the genital tract 2 months following HSV-2 tk- genital inoculation. These data suggest that the urogenital cellular immune response elicited in mice following genital inoculation with HSV-2 tk- is predominantly CD4+ and Th1-like, resembling that observed in humans. The results of this study are important for the rational design of vaccines capable of inducing protective immunity in the genital tract

High temperature low-cycle fatigue mechanisms in single crystals of nickel-based superalloy Mar-M 200

Twenty three high temperature low-cycle fatigue tests were conducted on single crystals of the nickel-based superalloy Mar-M 200. Tests were conducted at 760 and 870 C. SEM fractography and transmission electron microscopy were used to determine mechanisms responsible for the observed orientation dependent fatigue behavior. It has been concluded that the plastic characteristics of the alloy lead to orientation-dependent strain hardening and fatigue lives at 760 C. At 870 C, the elastic characteristics of the alloy dominated the behavior, even though the plastic strain ranges were about the same as they were at 760 C. This led to orientation-dependent fatigue lives, but the trends were not the same as they were at 760 C

Within-Litter Birth Weight Variation in the Domestic Pig and its Relation to Pre-Weaning Survival, Weight Gain, and Variation in Weaning Weights

To determine the relationship between within-litter birth weight variation and pre-weaning survival and weight gain, and to provide practical guidance on fostering low-birth-weight piglets, we analyzed piglet survival and weight gain in litters of piglets from 52 sows followed through eight consecutive parities. Litters with high variation in birth weight had more deaths, especially if the litter’s mean birth weight was low. High variation in birth weight was also associated with high variation in weaning weight, but was not significantly related to mean weaning weight. Piglets with birth weights well below the range of most of the litter (‘low-birth-weight piglets’) were more likely to die than their litter-mates, but their weight gains were normal for their birth weight if they survived. These piglets experienced particularly low survival in larger litters and litters from sows of sixth parity or older. Litters containing low-birth-weight piglets started, on average, with more piglets born alive and had a lower pre-weaning survival (with the majority of deaths being low-birth-weight piglets), but did not wean significantly more piglets than litters without low-birth-weight piglets. The majority of litters had a negatively skewed distribution of birth weights, with more piglets well below the mean than well above it. Our data are consistent with the hypothesis that high variation in birth weight contributes to reduced survival, at least for litters of low mean birth weight, and to variable weaning weights. Our data also support the hypothesis that in terms of survival, small piglets have a competitive disadvantage compared to their heavier litter-mates, a disadvantage that is exacerbated in large litters and litters from older sows. Our data suggest that selection for increased litter size that results in more low-birth-weight piglets per litter may not be beneficial unless measures are undertaken to improve the survival of low-birth-weight piglets

The promise and limits of private standards to reduce greenhouse gas emissions from shipping

This article examines private standards that aim to mitigate greenhouse gas (GHG) emissions in shipping. These have emerged against a backdrop of regulatory inertia and the exclusion of international shipping from the Paris Climate Change Agreement. They are a product of complex governance arrangements and they have addressed areas of market failure that have held back fuel efficiency advances that are made possible by technological innovations. These private standards hold considerable promise but suffer to different degrees from certain weaknesses, notably a lack of transparency, a low level of ambition and concerns about data reliability. This article examines these deficiencies together with the reasons for them, and assesses the role that law could play in addressing them. It argues that the conditions may be present for the mitigation of shipping’s GHG emissions to become a site of ‘hybrid’ governance, combining private standards and state/supra-state law in a productive way

Cercarial Transformation and in vitro Cultivation of Schistosoma mansoni Schistosomules

Schistosome parasites are the causative agents of schistosomiasis, a chronically debilitating disease that affects over 200 million people globally and ranks second to malaria among parasitic diseases in terms of public health and socio-economic impact (1-4). Schistosome parasites are trematode worms with a complex life cycle interchanging between a parasitic life in molluscan and mammalian hosts with intervening free-swimming stages. Briefly, free-swimming cercariae infect a mammalian host by penetrating the skin with the aid of secreted proteases, during which time the cercariae lose their tails, transforming into schistosomules. The schistosomules must now evade the host immune system, develop a gut for digestion of red blood cells, and migrate though the lungs and portal circulation en route to their final destination in the hepatic portal system and eventually the mesenteric veins (for S. mansoni) where male and female worms pair and mate, producing hundreds of eggs daily. Some of the eggs are excreted from the body into fresh water, where the eggs hatch into free-swimming miracidia (5-10). The miracidia infect specific snail species and transform into mother and daughter sporocysts, which in turn, produce infective cercariae, completing the life cycle. Unfortunately, the entire schistosome life cycle cannot be cultured in vitro, but infective cercariae can be transformed into schistosomules, and the schistosomules can be cultured for weeks for the analysis of schistosome development in vitro or microarray analysis. In this protocol, we provide a visual description of cercarial transformation and in vitro culturing of schistosomules. We shed infectious cercariae from the snail host Biomphalaria glabrata and manually transform them into schistosomules by detaching their tails using an emulsifying double-ended needle. The in vitro cercarial transformation and schistosomules culture techniques described avoid the use of a mammalian host, which simplifies visualization of schistosomes and facilitates the collection of the parasite for experimental analysis. in vitro transformation and culturing techniques of schistosomes have been done for years (11, 12), but no visual protocols have been developed that are available to the entire community

The Effect of Littermate Weight on Survival, Weight Gain, and Suckling Behavior of Low-Birth-Weight Piglets in Cross-Fostered Litters

Objective: To determine whether low-birth-weight piglets show better survival, weight gain, and suckling behavior when grouped with other small piglets by cross-fostering. Methods: We manipulated the number and size of foster littermates for low-birth-weight piglets in 31 small (eight or nine piglets) and 22 large (11 or 12 piglets) litters. Experimental litters were composed of four to six piglets of lowest birth weight and either four to six slightly heavier or four to six much heavier piglets from two combined litters. Results: Low-birth-weight piglets raised with much heavier littermates had somewhat lower survival rates, but showed no tendency towards lower weight gains or less successful suckling behavior than low-birth-weight piglets raised with slightly heavier littermates. The somewhat higher survival rate of low-birth-weight piglets raised with slightly heavier littermates was largely offset by more deaths in the foster littermates, so there was no overall reduction in total losses. Low-birth-weight piglets fought more when raised with slightly heavier piglets than with much heavier piglets, and they missed more nursing episodes and had smaller weight gains than littermates, regardless of littermate weight. Implications: Cross-fostering low-birth-weight pigs into litters with other small pigs, compared to fostering into litters with high-birth-weight pigs, slightly improved their survival, but did not affect their weight gain or ability to suckle successfully, nor overall litter survival, even in litters as large as 11 or 12 piglets. Cross-fostering low-birth-weight pigs to litters of similar birth weight increased the level of fighting

Within-Litter Birth Weight Variation in the Domestic Pig and its Relation to Pre-Weaning Survival, Weight Gain, and Variation in Weaning Weights

To determine the relationship between within-litter birth weight variation and pre-weaning survival and weight gain, and to provide practical guidance on fostering low-birth-weight piglets, we analyzed piglet survival and weight gain in litters of piglets from 52 sows followed through eight consecutive parities. Litters with high variation in birth weight had more deaths, especially if the litter’s mean birth weight was low. High variation in birth weight was also associated with high variation in weaning weight, but was not significantly related to mean weaning weight. Piglets with birth weights well below the range of most of the litter (‘low-birth-weight piglets’) were more likely to die than their litter-mates, but their weight gains were normal for their birth weight if they survived. These piglets experienced particularly low survival in larger litters and litters from sows of sixth parity or older. Litters containing low-birth-weight piglets started, on average, with more piglets born alive and had a lower pre-weaning survival (with the majority of deaths being low-birth-weight piglets), but did not wean significantly more piglets than litters without low-birth-weight piglets. The majority of litters had a negatively skewed distribution of birth weights, with more piglets well below the mean than well above it. Our data are consistent with the hypothesis that high variation in birth weight contributes to reduced survival, at least for litters of low mean birth weight, and to variable weaning weights. Our data also support the hypothesis that in terms of survival, small piglets have a competitive disadvantage compared to their heavier litter-mates, a disadvantage that is exacerbated in large litters and litters from older sows. Our data suggest that selection for increased litter size that results in more low-birth-weight piglets per litter may not be beneficial unless measures are undertaken to improve the survival of low-birth-weight piglets