Effect of processing route on ballistic performance of Ti-6Al-4V armour plate

Titanium alloys are a key part of an armour designer’s toolset due to their high ballistic mass efficiency. However, titanium’s high cost has restricted its use in military land-based vehicles. In this study, the effect of different processing routes on the microstructure, texture, ballistic performance V50 and deformation modes of Ti-6Al-4V armour plate is investigated. Plates were fabricated via conventional hot rolling and the powder metallurgy techniques of HIP and FAST. The plate failure modes varied significantly with the microstructure while the formation of adiabatic shear bands seems to be influenced by crystallographic texture. The rolled plate exhibited the best performance due to a strong transverse-type texture perpendicular to the projectile direction

Estimating Latent Variable Models When the Latent Variable is Observable

Logit and probit models are designed to estimate latent variable models. However, there are cases that these estimates are used, even though the latent variable is fully observable. The most prominent examples are studies about obesity, where they calculate BMI based on two observed variables: weight and height squared. They translate BMI into a binary variable (e.g. obese or not obese) and this index is used to examine factors affecting obesity. This study determines the loss in efficiency of using logit/probit models versus the conventional OLS (e.g. with unknown variance). We also compare the marginal effects between these models. The results suggest that OLS is a more efficient than the logit/probit models when estimating the true coefficients, regardless of the multicollinearity, fit of regression and cut-off probability. Likewise, OLS provided unbiased marginal effects compared to both binary response models. It is also less likely to be biased. We can conclude, that according to our Monte Carlo simulation, when the latent variable is observable, it is better to use the continous value and regress it with respect to their explanatory variable instead of converting it into a latent variable

A fulminant malignant hyperthermia episode in a patient with ryanodine receptor gene mutation p.Tyr522Ser

A 37-yr-old patient scheduled for elective bursectomy developed fulminant malignant hyperthermia (MH) under sevoflurane anesthesia. The first sign was a dramatic increase in end-tidal CO(2). Symptomatic and specific therapy was rapidly instituted. Postoperative rhabdomyolysis was treated with veno-venous hemofiltration. The patient rejected open muscle biopsy for in vitro contracture testing. Therefore, molecular testing was performed. An infrequent MH causative mutation was identified on the ryanodine receptor gene. This case report confirms the causative nature of this mutation. It also shows that molecular genetic investigation may be as appropriate as in vitro contracture testing to confirm the diagnosis after a clinical episode of MH

All Akt Isoforms (Akt1, Akt2, Akt3) Are Involved in Normal Hearing, but Only Akt2 and Akt3 Are Involved in Auditory Hair Cell Survival in the Mammalian Inner Ear

The kinase Akt is a key downstream mediator of the phosphoinositide-3-kinase signaling pathway and participates in a variety of cellular processes. Akt comprises three isoforms each encoded by a separate gene. There is evidence to indicate that Akt is involved in the survival and protection of auditory hair cells in vitro. However, little is known about the physiological role of Akt in the inner ear-especially in the intact animal. To elucidate this issue, we first analyzed the mRNA expression of the three Akt isoforms in the inner ear of C57/BL6 mice by real-time PCR. Next, we tested the susceptibility to gentamicin-induced auditory hair cell loss in isoform-specific Akt knockout mice compared to wild-types (C57/BL6) in vitro. To analyze the effect of gene deletion in vivo, hearing and cochlear microanatomy were evaluated in Akt isoform knockout animals. In this study, we found that all three Akt isoforms are expressed in the cochlea. Our results further indicate that Akt2 and Akt3 enhance hair cell resistance to ototoxicity, while Akt1 does not. Finally, we determined that untreated Akt1 and Akt2/Akt3 double knockout mice display significant hearing loss, indicating a role for these isoforms in normal hearing. Taken together, our results indicate that each of the Akt isoforms plays a distinct role in the mammalian inner ear