Search results for "Stability"

Physiological Mechanisms of Treatment Resistance

2009

It is generally accepted that tumor perfusion, microcirculation, characteristics of the interstitial space of tumors, oxygen (and nutrient) supply, tissue pH distribution and the bioenergetic status—factors that are usually closely linked and that define the so-called pathophysiological microenvironment—can markedly influence the therapeutic response of malignant tumors to sparsely ionizing radiation, chemotherapy, photodynamic therapy, hormonal therapy and immunotherapy. Besides more direct mechanisms involved in the development of acquired therapeutic resistance, there are in addition, obstacles in intratumor pharmacokinetics of antitumor agents due to delivery problems caused by an inade…

Genome structure reveals the diversity of mating mechanisms in Saccharomyces cerevisiae x Saccharomyces kudriavzevii hybrids, and the genomic instabi…

2020

Interspecific hybridization has played an important role in the evolution of eukaryotic organisms by favouring genetic interchange between divergent lineages to generate new phenotypic diversity involved in the adaptation to new environments. This way, hybridization between Saccharomyces species, involving the fusion between their metabolic capabilities, is a recurrent adaptive strategy in industrial environments. In the present study, whole-genome sequences of natural hybrids between Saccharomyces cerevisiae and Saccharomyces kudriavzevii were obtained to unveil the mechanisms involved in the origin and evolution of hybrids, as well as the ecological and geographic contexts in which sponta…

Patterns of genomic instability in gastric cancer: clinical implications and perspectives

2007

In gastric cancer (GC) the loss of genomic stability represents a key molecular step that occurs early in the carcinogenesis process and creates a permissive environment for the accumulation of genetic and epigenetic alterations in tumor suppressor genes and oncogenes. It is widely accepted that GC can follow at least two major genomic instability pathways, microsatellite instability (MSI) and chromosome instability (CIN). MSI is responsible for a well-defined subset of GCs. CIN represents a more common pathway comprising heterogeneous subsets of GC. In addition to MSI and CIN, the CpG islands methylator phenotype (CIMP) plays an important role in gastric carcinogenesis. CIMP may lead to th…

Differential diagnosis problems in a patient with dysphonia and chronic lymphocytic leukemia

2014

SUMMARY Dysphonia is frequently an expression of laryngitis, especially when it comes in the evolution of an immunosuppressed patient, as happens in chronic lymphoproliferation. But other causes of dysphonia should also not be forgotten, including the possibility of new malignancies, especially due to the fact that these patients have genomic instability that predisposes to appearance of a second or even a third cancer. We present the case of a patient who developed dysphonia during chronic lymphocytic leukemia evolution. Its etiology was a mediastinal compression through lymph nodes, not linked to leukemia, but produced by metastases of a bronchopulmonary cancer, appeared recently. Dysphon…

Recovery of time-dependent coefficients from boundary data for hyperbolic equations

2019

We study uniqueness of the recovery of a time-dependent magnetic vector-valued potential and an electric scalar-valued potential on a Riemannian manifold from the knowledge of the Dirichlet to Neumann map of a hyperbolic equation. The Cauchy data is observed on time-like parts of the space-time boundary and uniqueness is proved up to the natural gauge for the problem. The proof is based on Gaussian beams and inversion of the light ray transform on Lorentzian manifolds under the assumptions that the Lorentzian manifold is a product of a Riemannian manifold with a time interval and that the geodesic ray transform is invertible on the Riemannian manifold.

Modelling the spatial-temporal progression of the 2009 A/H1N1 influenza pandemic in Chile

2016

A spatial-temporal transmission model of 2009 A/H1N1 pandemic influenza across Chile, a country that spans a large latitudinal range, is developed to characterize the spatial variation in peak timing of that pandemic as a function of local transmission rates, spatial connectivity assumptions for Chilean regions, and the putative location of introduction of the novel virus into the country. Specifically, a metapopulation SEIR (susceptible-exposed-infected-removed) compartmental model that tracks the transmission dynamics of influenza in 15 Chilean regions is calibrated. The model incorporates population mobility among neighboring regions and indirect mobility to and from other regions via th…

Reliability Analysis of a Controlled Stage-Constructed and Reinforced Embankment on Soft Ground Using 2D and 3D Models

2020

Geosynthetic reinforcement has become a very practical technique to improve geotechnical structure safety. In spite of improved soil behavior, structures are affected by uncertainties related to soil and reinforcement material properties. This paper aims to present a reliability analysis in order to take statistical information (uncertainties) into account in a safety analysis of reinforced embankments. The analysis was used in a case study on a controlled stage-constructed embankment on soft ground in order to investigate its probabilistic stability. Modeling was performed by commercial geotechnical software usage (GeoStudio and RocScience packs, SIGMA/W+SLOPE/W and SLIDE³, respectively) a…

Development of the One Centimeter Accuracy Geoid Model of Latvia for GNSS Measurements

2015

There is an urgent necessity for a highly accurate and reliable geoid model to enable prompt determination of normal height with the use of GNSS coordinate determination due to the high precision requirements in geodesy, building and high precision road construction development. Additionally, the Latvian height system is in the process of transition from BAS- 77 (Baltic Height System) to EVRS2007 system. The accuracy of the geoid model must approach the precision of about ~1 cm looking forward to the Baltic Rail and other big projects. The use of all the available and verified data sources is planned, including the use of enlarged set of GNSS/levelling data, gravimetric measurement data and…

Pattern formation in 3-D numerical models of down-built diapirs initiated by a Rayleigh–Taylor instability

2015

Physical balance of 12-13 year old adolescents in Latvia: problems and solutions

2016

The paper is prepared within the framework of the National science programme “Innovative solutions for social telerahabilitation in the schools of Latvia in the context of inclusive education (INOSOCTEREHI)”. The paper focuses on the adolescents’ balance disorders. Equipment for balance testing BIOSWAY was used in the case study. It showed that almost every fourth adolescent of the age 12-13 years has the total postural stability index below the norm. Only 9.4% of adolescents have normal overall balance control results. It is necessary to find ways how to reduce the identified problem within the context of inclusive education.