Foreign object damage (FOD), e.g. a bird strike, is seriously damaging event during flight operations of aviation. For simulating bird strike, soft-body impact test is investigated and gelatin is used as the projectile material traditionally. However, the effect of projectile shape on the soft-body impact test results has not been sufficiently established. In this study, a cantilever target made from aluminum alloy and carbon fiber/epoxy composite were used, and experiments and FEM simulations were conducted to investigate the effect of the projectile shape. The projectile shape should affect impulse and/or work immediately after impact, and it affects the plastic deformation around the impact point of aluminum alloy specimen. And the projectile shape should affect the interlaminar shear stress around the impact point and edge of specimen, and affects the delamination of carbon/epoxy composites specimen.

In this article, we report the complete coding sequence and to our knowledge, the first functional analysis of two homologous nonclassical MHC class II genes: RT1-Db2 of rat and H2-Eb2 of mouse. They differ in important aspects compared with the classical class II β1 molecules: their mRNA expression by APCs is much lower, they show minimal polymorphism in the Ag-binding domain, and they lack N-glycosylation and the highly conserved histidine 81. Also, their cytoplasmic region is completely different and longer. To study and compare them with their classical counterparts, we transduced them in different cell lines. These studies show that they can pair with the classical α-chains (RT1-Da and H2-Ea) and are expressed at the cell surface where they can present superantigens. Interestingly, compared with the classical molecules, they have an extraordinary capacity to present the superantigen Yersinia pseudotuberculosis mitogen. Taken together, our findings suggest that the b2 genes, together with the respective α-chain genes, encode for H2-E2 or RT1-D2 molecules, which could function as Ag-presenting molecules for a particular class of Ags, as modulators of Ag presentation like nonclassical nonpolymorphic class II molecules DM and DO do, or even as players outside the immune system.

An aircraft may suffer from foreign object damage (FOD) during flight operations, and a bird strike is a potentially serious and damaging FOD event. For simulated bird strike experiments, gelatin has been traditionally used as the projectile material. However it has not been determined how the projectile's shape affects the soft body impact. In this study, three types of projectile's shapes are used to investigate and two types of impact tests are conducted. One uses a solid target with a flat face and the pressure change is investigated. The other uses a cantilever target made from aluminum alloy to investigate the deformation after impact. From these experiments and numerical analysis of the impact test for cantilever specimen, the effects of the projectile's shape are evaluated.

ABSTRACT Staphylococcal enterotoxins (SEs) are a common causative agent of food poisoning. Recently, many new SE-like (SEl) toxins have been reported, although the role of SEls in food poisoning remains unclear. In this study, the emetic potentials of SElK, SElL, SElM, SElN, SElO, SElP, and SElQ were assessed using a monkey-feeding assay. All the SEls that were tested induced emetic reactions in monkeys at a dose of 100 μg/kg, although the numbers of affected monkeys were significantly smaller than the numbers that were affected after consuming SEA or SEB. This result suggests that these new SEs may play some role in staphylococcal food poisoning.

Since 1992, many neonates in neonatal intensive care units in Japan have been developing fever and systemic exanthema. Immunological analyses of neonates with these symptoms has revealed that the bacterial superantigen, toxic shock syndrome toxin-1 (TSST-1) is the cause. The name neonatal TSS-like exanthematous disease (NTED) has been applied to this condition. The most striking clinical finding has been that none of the term neonates have developed shock or died of NTED. The timing of NTED epidemics has coincided with the spread of emerging TSST-1-producing methicillin-resistant Staphylococcus aureus clones in Japan. The low frequency of pregnant women with positive anti-TSST-1 antibody titers could be one reason for the spread of NTED in Japan. Neonates have immune tolerance against TSST-1 and may actively suppress the immune response to NTED with interleukin-10. According to the T cell responses in infants or young children with diseases induced by TSST-1, the pathophysiology of TSST-1-related diseases may be age-dependent. The precise mechanism of anergy and deletion of specific T cells stimulated with TSST-1 should be investigated in neonates infected with NTED. Both NTED and TSS might provide good models for analyzing the mechanism(s) of neonatal immune tolerance and the age-dependence of human immunity. This disease has not only become representative of diseases caused by superantigens, but has also yielded a considerable amount of evidence about human immune reactions against superantigens.

Micro Spark Coating (MSC) has been developed as a new functional coating process for Ni-based superalloys used in advanced gas turbines. In this study, some metallurgical and mechanical properties of a MSC layer made of a Co-based wear resisting alloy (X40), and its influence on the high temperature fatigue properties of Ni-based superalloy, Alloy718, were investigated. Prior evaluation of the metallurgical and mechanical properties of the MSC layer that the cavity fraction of MSC layer significantly decreased during the thermal exposure period at 650°C associating with the generation of an oxide phase, progressive sintering and the subsequent increase in hardness and elastic modulus of MSC layer. However, at 480°C these changes were not significant even after 1000hrs exposure. It was found from the high temperature fatigue tests at 480°C and 650°C that the fatigue life of the specimen with MSC layer was almost comparable to that of bare Alloy718 specimen at 480°C, while at 650°C the life of the former was slightly longer than that of the latter. These results suggested that the MSC would have a potential to add a new function to Ni-based superalloy without a reduction in fatigue properties at elevated temperature.

An aircraft may suffer from foreign object damage (FOD) during flight operations, and a bird strike is a potentially serious and damaging FOD event. For simulated bird strike experiments, gelatin has been traditionally used as the projectile material. However, it has not been sufficiently determined how the material properties of the projectile affect the simulated bird strike results, especially for deformable targets. In this work, using gelatin as the conventional simulated bird material, silicone resin is used to investigate the effects of the projectile material properties. Two types of impact tests are conducted. One uses a solid target with a flat face, and the pressure change due to the impact is investigated. The other uses a cantilever target made from aluminum alloy or carbon fiber/epoxy composite laminate to investigate the plastic deformation or damage, respectively. From these experiments, the effects of the projectile material type and properties are evaluated.

A single subcutaneous (s.c.) infection with 1×107 c.f.u. GAS472, a group A streptococcus (GAS) serotype M1 strain isolated from the blood of a patient suffering from streptococcal toxic shock syndrome, led to severe damage of striated muscle layers in the feet of mast cell (MC)-deficient WBB6F1-KitW/KitW-v (W/Wv ) mice 72 h after infection. In contrast, no damage was recognized in striated muscle layers in the feet of the control WBB6F1-Kit +/+ (+/+) mice 72 h after infection. In addition, adoptively transferred MCs reduced progressive tissue necrosis of the feet of W/Wv mice after infection. However, there was no significant difference in the mortality rates between the W/Wv and +/+ mice, or between the human CD46-expressing transgenic (Tg) mouse bone marrow-derived cultured MC-reconstituted W/Wv and non-Tg mouse bone marrow-derived cultured MC-reconstituted W/Wv mice after infection. Consequently, although MCs can help to reduce the severity of necrosis of the feet caused by s.c. infection with GAS472, such reduction of tissue necrosis scarcely improves the mortality rates of these mice. Moreover, human CD46 does not play a crucial role in the MC-mediated innate immune defence against GAS infection.

High temperature fatigue (HCF) properties of the A11oy718 superalloy specimens to aich a Co-based wear resisting alloy was coated by the Micro Spark Coating (MSC) method, were investigated at two elevated temperature, 480℃ and 650℃, respectively. It was revealed that the HCF life of coated specimen was slightly shorter than the life of bare specimen at 480℃. On the other hand, the HCF lives were longer at 650℃. The most of fracture surface were placed on the end of coating region in gage part at both temperatures. Form the elastic analysis using finite element method, the stress concentration had been occurred in the end of coating region. It was suggested that high temperature fatigue properties were influenced by two phenomena: one was the stress concentration that was based on the shape and mechanical properties of the MSC layer; and the other was a load transfer capability of the coated area, dependent on the test temperature and exposure time.

In mice implanted with an osmotic pump filled with the superantigen (SAG) staphylococcal enterotoxin A (SEA), the Vβ3(+)CD4(+) T cells exhibited a high level of expansion whereas the Vβ11(+)CD4(+) T cells exhibited a mild level of expansion. In contrast, in mice implanted with an osmotic pump filled with SE-like type P (SElP, 78.1% homologous with SEA), the Vβ11(+)CD4(+) T cells exhibited a high level of expansion while the Vβ3(+)CD4(+) T cells exhibited a low level of expansion, suggesting that the level of the SAG-induced response is determined by the affinities between the TCR Vβ molecules and SAG. Analyses using several hybrids of SEA and SElP showed that residue 206 of SEA determines the response levels of Vβ3(+)CD4(+) and Vβ11(+)CD4(+) T cells both in vitro and in vivo. Analyses using the above-mentioned hybrids showed that the binding affinities between SEA and the Vβ3/Vβ11 β chains and between SEA-MHC class II-molecule complex and Vβ3(+)/Vβ11(+) CD4(+) T cells determines the response levels of the SAG-reactive T cells both in vitro and in vivo.

Bacterial infection has become a focus of attention in the pathogenesis of primary biliary cirrhosis (PBC). We earlier reported that the bacterial lipoteichoic acid was detected at the sites of inflammation around damaged bile ducts in the livers of PBC, and PBC patients' sera showed high titers against streptococcal histone-like protein. Here, we investigated whether chronic bacterial exposure could trigger PBC-like epithelial cell damage in normal mouse. BALB/c mice were repeatedly inoculated with various bacteria for 8 weeks. At 1 week (Group 1) and 3, 4, or 20 months (long term; Group 2) after the final inoculation, mice were killed to obtain samples. In the livers of the Streptococcus intermedius (S.i.)-inoculated mice in Group 1, cellular infiltration was predominantly observed around the bile ducts over the hepatic parenchyma. In the S.i.-inoculated mice in Group 2, portal but not parenchymal inflammation was observed in the livers, and periductal cellular infiltrates were detected in the salivary glands. Both S.i.-inoculated Groups 1 and 2 BALB/c mice sera had antibodies against HuCCT1 biliary epithelial cells, anti-nuclear antibodies, and anti-gp210 antibodies, but not anti-mitochondrial antibodies. Immunoreactivity to histone-like DNA-binding protein of S.i. (S.i.-HLP) was detectable around the sites of chronic nonsuppurative destructive cholangitis in the portal area in the livers of both S.i.-inoculated Groups 1 and 2 BALB/c mice. Furthermore, anti-S.i.-HLP antibody bound to synthetic gp210 peptide, as well. Bacteria triggered PBC-like cholangitis, multifocal epithelial inflammation, and autoantibody production. Bacteria are likely involved in the pathogenesis of PBC and of associated multifocal epithelial inflammation.

The aim of this study was to determine the percentage of CD45RO+ T cells in umbilical cord blood from neonates born at less than 37 weeks of gestation. Fifty-nine patients were enrolled in this study, including 49 with preterm and 10 with term deliveries. Preterm deliveries were divided into two categories; spontaneous (Group A, n = 31) and indicated (Group B, n = 18). Perinatal infection was categorized as C-CAM, H-CAM and neonatal infection. The percentage of CD45RO+ T cells in the umbilical cord was assessed using flow cytometry. IL-6 was measured using ELISA. In Group A, the percentage of CD45RO+ T cells and concentrations of IL-6 in patients with perinatal infection (n = 18) were significantly higher than in those without perinatal infection (n = 13). A significant correlation between percentage of CD45RO+ T cells and IL-6 concentrations was observed in the cord blood (r = 0.62, P = 0.001). In Group B, pink-tinged amniotic fluid was observed in seven cases. In these cases, an increase in the percentage of CD45RO+ T cells (> 10%) was noted. In the cases without perinatal infection, which included all those delivered at term (n = 32), no correlation was observed between the percentage of CD45RO+ T cells and gestational age at delivery (r = -0.139, P = 0.448). We concluded that a high percentage of CD45RO+ cord blood T cells is observed not only in perinatal infection, but also in the presence of abnormal perinatal events such as maternal bleeding in preterm gestation.

To elucidate whether leukocyte cell-derived chemotaxin 2 (LECT2) controls the progression of staphylococcal enterotoxin A (SEA)-induced toxicity, we examined the role of LECT2 in a mouse model. Almost all the C57BL/6 J (B6) mice survived for 72 h after the injection of 0.1 μg of SEA and 20 mg of d-galactosamine (d-GalN). However, the same treatment protocol in LECT2−/− mice produced a high lethality (~ 90%), severe hepatic apoptosis, and massive hepatic and pulmonary hemorrhage, similar to the situation observed in B6 mice treated with 1.0 μg SEA/d-GalN. The plasma LECT2 levels in B6 mice treated with 1.0 μg SEA/d-GalN were inversely correlated with the plasma cytokine levels and were associated with prognosis. LECT2 administration increased the survival of B6 mice and down-regulated TNF-α and IL-6. These results suggest the involvement of LECT2 in the regulation of fatal SEA-induced toxicity in d-GalN-sensitized mice.

PI3K plays crucial roles in the immune system. Mice deficient for p85α, a major regulatory subunit of class IA PI3K, show various defects and alterations in B cells, mast cells, macrophages, and DCs, and peripheral T cells are reportedly normal, at least in vitro. In normal mice, long‐term exposure to a SAg, SEA, in vivo induced a high level of the protracted expansion of SEA‐reactive Vβ3+CD4+ T cells, whereas the same treatment induced T cell expansion in p85α‐deficient mice but to a much lesser extent than in normal mice. However, mixed bone marrow chimera mice, which have normal and p85α‐deficient T and B cells, demonstrated equal responses of both T cells following stimulation with a SEA pump. In reciprocal cotransfer experiments of T and B cells from normal and p85α‐deficient mice into Rag2‐deficient mice, followed by SEA stimulation, p85α‐deficient T cells revealed much higher proliferative capacity in the presence of normal B cells than did normal T cells with p85α‐deficient B cells. Histologically, a marked B cell reduction was observed in the follicles and MZ of the spleen, and DCs accumulated in the MZ. In addition, p85α‐deficient B cells had a low level of MHC class II expression. Collectively, these data suggested that the PI3K p85α subunit alters the SAg presentation capacity of B cells and indirectly modulates the magnitude of the T cell response, which may affect the protection against SEA‐containing bacteria.

SummaryRat major histocompatibility complex (MHC) class II molecules RT1.Bl (DQ‐like) and RT1.Dl (DR‐like) were cloned from the LEW strain using reverse transcription–polymerase chain reaction and expressed in mouse L929 cells. The transduced lines bound MHC class II‐specific monoclonal antibodies in an MHC‐isotype‐specific manner and presented peptide antigens and superantigens to T‐cell hybridomas. The T‐cell‐hybridomas responded well to all superantigens presented by human MHC class II, whereas the response varied considerably with rat MHC class II‐transduced lines as presenters. The T‐cell hybridomas responded to the pyrogenic superantigens Staphylococcus enterotoxin B (SEB), SEC1, SEC2 and SEC3 only at high concentrations with RT1.Bl‐transduced and RT1.Dl‐transduced cells as presenters. The same was true for streptococcal pyrogenic exotoxin A (SPEA), but this was presented only by RT1.Bl and not by RT1.Dl. SPEC was recognized only if presented by human MHC class II. Presentation of Yersinia pseudotuberculosis superantigen (YPM) showed no MHC isotype preference, while Mycoplasma arthritidis superantigen (MAS or MAM) was presented by RT1.Dl but not by RT1.Bl. Interestingly, and in contrast to RT1.Bl, the RT1.Dl completely failed to present SEA and toxic shock syndrome toxin 1 even after transduction of invariant chain (CD74) or expression in other cell types such as the surface MHC class II‐negative mouse B‐cell lymphoma (M12.4.1.C3). We discuss the idea that a lack of SEA presentation may not be a general feature of RT1.D molecules but could be a consequence of RT1.Dlβ‐chain allele‐specific substitutions (arginine 80 to lysine, asparagine 82 to aspartic acid) in the extremely conserved region flanking the Zn2+‐binding histidine 81, which is crucial for high‐affinity SEA‐binding.