2,412 research outputs found
MProtect: Operating System Memory Management without Access
Modern operating systems (OSes) have unfettered access to application data,
assuming that applications trust them. This assumption, however, is problematic
under many scenarios where either the OS provider is not trustworthy or the OS
can be compromised due to its large attack surface. Our investigation began
with the hypothesis that unfettered access to memory is not fundamentally
necessary for the OS to perform its own job, including managing the memory. The
result is a system called MProtect that leverages a small piece of software
running at a higher privilege level than the OS. MProtect protects the entire
user space of a process, requires only a small modification to the OS, and
supports major architectures such as ARM, x86 and RISC-V. Unlike prior works
that resorted to nested virtualization, which is often undesirable in mobile
and embedded systems, MProtect mediates how the OS accesses the memory and
handles exceptions. We report an implementation of MProtect called MGuard with
ARMv8/Linux and evaluate its performance with both macro and microbenchmarks.
We show MGuard has a runtime TCB 2~3 times smaller than related systems and
enjoys competitive performance while supporting legitimate OS access to the
user space
Salvianolic Acid B Prevents Arsenic Trioxide-Induced Cardiotoxicity In Vivo and Enhances Its Anticancer Activity In Vitro
Clinical attempts to reduce the cardiotoxicity of arsenic trioxide (ATO) without compromising its anticancer activities remain to be an unresolved issue. In this study, we determined whether Sal B can protect against ATO-induced cardiac toxicity in vivo and increase the toxicity of ATO toward cancer cells. Combination treatment of Sal B and ATO was investigated using BALB/c mice and human hepatoma (HepG2) cells and human cervical cancer (HeLa) cells. The results showed that the combination treatment significantly improved the ATO-induced loss of cardiac function, attenuated damage of cardiomyocytic structure, and suppressed the ATO-induced release of cardiac enzymes into serum in BALB/c mouse models. The expression levels of Bcl-2 and p-Akt in the mice treated with ATO alone were reduced, whereas those in the mice given the combination treatment were similar to those in the control mice. Moreover, the combination treatment significantly enhanced the ATO-induced cytotoxicity and apoptosis of HepG2 cells and HeLa cells. Increases in apoptotic marker cleaved poly (ADP-ribose) polymerase and decreases in procaspase-3 expressions were observed through western blot. Taken together, these observations indicate that the combination treatment of Sal B and ATO is potentially applicable for treating cancer with reduced cardiotoxic side effects
Strong supersymmetric quantum effects on top quark production at the Fermilab Tevatron
The supersymmetric QCD corrections to top quark pair production by
annihilation in collisions are calculated in the minimal
supersymmetric model. We consider effects of the mixing of the scalar top
quarks on the corrections to the total production cross section at
the Fermilab Tevatron. We found that such correction is less sensitive to
squark mass and gluino mass than in no-mixing case, and in both cases the
corrections can exceed 10\% even if we consider the recent CDF limit on squark
and gluino masses.Comment: 11 pages, 3 figures, accepted by Phys.Lett.B in Apr.1,199
Epigenetic toxicity and cytotoxicity of perfluorooctanoic acid and its effects on gene expression in embryonic mouse hypothalamus cells
Premda je perfluorooktanska kiselina (PFOA) dobro znana kao endokrini disruptor, i dalje se malo zna o mehanizmima u pozadini njezina djelovanja na stanice i njezine toksičnosti u kritičnoj fazi razvoja hipotalamusa. Stoga smo istražili njezino djelovanje u staničnoj liniji N46 hipotalamusa mišjeg embrija (mHypoE-N46) da bismo saznali o mehanizmima kroz koje ih PFOA oštećuje. S tom smo svrhom analizirali vijabilnost stanica, globalnu metilaciju DNA i gensku ekspresiju izloženih stanica. Porastom koncentracija PFOA padala je stanična vijabilnost, a globalna DNA metilacija rasla. Usto je PFOA značajno utjecala na ekspresiju gena povezanih s apoptozom i staničnim ciklusom, neurotrofnih gena te Tet, Dnmt i Mecp2 gena. Naše istraživanje ukazuje na to da izloženost PFOA utječe na preživljenje stanica hipotalamusa mišjeg embrija reprogramiranjem obrazaca metilacije DNA te promjenama u genima zaduženim za održavanje homeostaze. Metilacija DNA i promjene u ekspresiji Mecp2 gena izazvane djelovanjem PFOA također imaju široki spektar implikacija, budući da utječu na promjene u genima zaduženim za druge važne mehanizme u embrijskom hipotalamusu. Stoga naše istraživanje može poslužiti kao dobra polazna točka za daljnje istraživanje mehanizama djelovanja PFOA na razvoj hipotalamusa.Even though the endocrine-disrupting potential of perfluorooctanoic acid (PFOA) is well known, the mechanisms underlying its cellular and epigenetic toxicity at the critical stage of hypothalamic development are poorly understood. This is why we studied its effects on the embryonic mouse hypothalamic cell line N46 (mHypoE-N46) with a hope to shed more light on the mechanisms through which PFOA causes embryonic hypothalamic cell damage. To do that, we studied cell viability, global DNA methylation, and gene expression in cells exposed to PFOA. As the PFOA dose increased, cell viability decreased, while global DNA methylation increased. PFOA also significantly altered the expression of genes related to the apoptosis and cell cycle, neurotrophic genes, and the Tet, Dnmt, and Mecp2 genes. Our findings suggest that exposure to PFOA affects cell survival through the reprogramming of embryonic hypothalamic DNA methylation patterns and altering cell homeostasis genes. DNA methylation and changes in the Mecp2 gene expression induced by PFOA also imply wider ramifications, as they alter genes of other major mechanisms of the embryonic hypothalamus. Our study may therefore serve as a good starting point for further research into the mechanisms of PFOA effect of hypothalamic development
Assessing the utility of structure in amorphous materials
This paper presents a set of general strategies for the analysis of structure
in amorphous materials and a general approach to assessing the utility of a
selected structural description. Measures of structural diversity and utility
are defined and applied to two model glass forming binary atomic alloys. In
addition, a new measure of incipient crystal-like organization is introduced,
suitable for cases where the stable crystal is a compound structure
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