MODEL OF M-M/S-CD MEMORY MANAGEMENT

This report introduces the M-M/S-CD memory management model which was designed for true microkernels as an alternative to capability-based memory management. The proposed model is more simple in design and implementation and provides more power and flexibility to the user mode memory management servers. In the same time it maintains consistency of memory layout and enforces strict and clear memory isolation/sharing rules, creating stable environment for applications

Ultra-Sensitive CSF3R Deep Sequencing in Patients With Severe Congenital Neutropenia

High frequency of acquired CSF3R (colony stimulating factor 3 receptor, granulocyte) mutations has been described in patients with severe congenital neutropenia (CN) at pre-leukemia stage and overt acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Here, we report the establishment of an ultra-sensitive deep sequencing of a CSF3R segment encoding the intracellular “critical region” of the G-CSFR known to be mutated in CN-MDS/AML patients. Using this method, we achieved a mutant allele frequency (MAF) detection rate of 0.01%. We detected CSF3R mutations in CN patients with different genetic backgrounds, but not in patients with other types of bone marrow failure syndromes chronically treated with G-CSF (e.g., Shwachman-Diamond Syndrome). Comparison of CSF3R deep sequencing results of DNA and cDNA from the bone marrow and peripheral blood cells revealed the highest sensitivity of cDNA from the peripheral blood polymorphonuclear neutrophils. This approach enables the identification of low-frequency CSF3R mutant clones, increases sensitivity, and earlier detection of CSF3R mutations acquired during the course of leukemogenic evolution of pre-leukemia HSCs of CN patients. We suggest application of sequencing of the entire CSF3R gene at diagnosis to identify patients with inherited lost-of-function CSF3R mutations and annual ultra-deep sequencing of the critical region of CSF3R to monitor acquisition of CSF3R mutations

Mechanism for radiation damage resistance in yttrium oxide dispersion strengthened steels

ODS steels based on yttrium oxide have been suggested as potential fusion reactor wall materials due to their observed radiation resistance properties. Presumably this radiation resistance can be related to the interaction of the particle with vacancies,self-interstitial atoms (SIAs) and other radiation damage debris. Density functional theory has been used to investigate this at the atomic scale. Four distinct interfaces, some based on HRTEM observations, between iron and yttrium oxide were investigated. It is been shown that the Y$_2$O$_3$-Fe interface acts as a strong trap with long-range attraction for both interstitial and vacancy defects, allowing recombination without altering the interface structure. The catalytic elimination of defects without change to the microstructure explains the improved behaviour of ODS steels with respect to radiation creep and swelling

Measuring Overhead of Concurrency and Virtual Memory

We present the methodology, as well as results of measurements and evaluation of overhead created by concurrency and virtual memory. A special measurement technique and testbed were used to obtain the most accurate data from the experiments. This technique is focused on the measurements of the overall performance degradation that is introduced by concurrency in the form of lightweight user-level threads on IA-32 processors. We have obtained and compared results of the experiments in an environment with and without enabled virtual memory to understand what loss of performance is caused by virtual memory in itself, and how it affects the overhead associated with concurrency. The results showed that overhead of concurrency outweighs virtual memory overhead and that there is a complex dependency between them. The article is published in the author’s wording