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Complementary analysis of microsatellite tumor profile and mismatch repair defects in colorectal carcinomas

World journal of Gastroenterology 2006年第37期12卷 5932-5940页

作者： alfredo Blanes Salvador j Diaz-Cano Department of Pathology University of Malaga School of Medicine Malaga 29010 Spain Department of Histopathology King’s College Hospital and King’s College London School of Medicine London SE5 9RS United Kingdom

Microsatellite instability (MSI) is a prognostic factor and a marker of defi cient mismatch repair (MMR) in colorectal adenocarcinomas (CRC). However, a proper application of this marker requires understanding the following: (1) The MSI concept: The PCR approach must amplify the correct locus and accurately identify the microsatellite pattern in the patient’s normal tissue. MSI is demonstrat- ed when the length of DNA sequences in a tumor differs from that of nontumor tissue. Any anomalous expansion or reduction of tandem repeats results in extra-bands normally located in the expected size range (100 bp, above or below the expected product), differ from the germline pattern by some multiple of the repeating unit, and must show appropriate stutter. (2) MSI mechanisms: MMR gene inactivation (by either mutation or protein down-regulation as frequently present in deep CRC com- partments) leads to mutation accumulation in a cell with every cellular division, resulting in malignant transforma- tion. These mechanisms can express tumor progression and result in a decreased prevalence of aneuploid cells and loss of the physiologic cell kinetic correlations in the deep CRC compartments. MSI molecular mechanisms are not necessarily independent from chromosomal in- stability and may coexist in a given CRC. (3) Because of intratumoural heterogeneity, at least two samples from each CRC should be screened, preferably from the su- perfi cial (tumor cells above the muscularis propria) and deep (tumor cells infi ltrating the muscularis propria) CRC compartments to cover the topographic tumor hetero- geneity. (4) Pathologists play a critical role in identify- ing microsatellite-unstable CRC, such as occur in young patients with synchronous or metachronous tumors or with tumors showing classic histologic features. In these cases, MSI testing and/or MMR immunohistochemistry are advisable, along with gene sequencing and genetic counseling if appropriate. MSI is an excellent functional an

关键词： Colon carcinoma Microsatellites Mismatch Repair Hereditary non-polyposis colon cancer

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Photomechanical Ablation of 304L Stainless Steel, Aluminum Oxide (Al₂O₃) Thin Film, and Pure Silicon

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Optics and Photonics journal 2016年第10期6卷 275-288页

作者： Gabriel de la Rosa-Santana j.se alfredo alvarez-chavez Hector R. Morano-Okuno Angel j. Morales-Ramirez Esmeralda Uribe Instituto Tecnologico y de Estudios Superiores de Monterrey Campus Estado de Mexico Atizapan de Zaragoza Mexico Instituto Politecnico Nacional-Centro de Investigacion e InnovacionTecnologica (CIITEC-IPN) Mexico City Mexico Instituto Tecnologico y de Estudios Superiores de Monterrey Campus Queretaro Santiago de Queretaro Mexico

Recently, a number of studies have focused on micro-manufacturing processes, which find use in a variety of applications, including the production of microelectromechanical systems (MEMS). The process of ablation in materials is mainly governed by the laser source and scanning speed. The rate of material ablation is influenced by chemical and physical properties. In this work, the energy from a CO2 laser was used to ablate three different materials, namely, stainless steel 304L, a thin film of amorphous aluminum oxide (Al2O3), and pure silicon, due to their wide use in MEMS technology. The laser parameters used were an average power of 18 W and a spot size of 200 μm. The maximum depth during the photomechanical ablation process was 72 μm in the case of 304L steel and 77 μm in the case of the Al2O3 thin film for a scan rate of 24 mm/min. However, at the same scan rate, silicon did not exhibit any penetration. As expected, while increasing scanning speed the ablation depth decreases due to reduced interaction time between laser and material. The theoretical ytterbium fiber laser shown in this study can thus be employed in the manufacturing of a wide variety of materials used in the production of MEMS as well as those used in clean energy technologies.

关键词： Laser Ablation MEMS Ytterbium-Doped Fiber Laser Thin Film

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Effect of growth rate on microstructure and solute distribution of Al-Zn-Mg alloy

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Transactions of Nonferrous Metals Society of China 2015年第5期25卷 1391-1398页

作者： A.L.RAMIREZ-LEDESMA R.A.RODRíGUEZ-DíAZ j.chavez-CARVAYAR O.alvarez-FREGOSO j.A.jUAREZ-ISLAS Materials Research Institute National Autonomous Universtiy of Mexico Circuito Exterior S/NCd. Universitaria Polytechnic University of the State of Morelos Boulevard Cuauhnahuac 556Col. Lomas del Texcal

An Al-5.3%Zn-5.3%Mg alloy was unidirectionally solidified to determine morphological transition and solute distribution by a modification of the Bridgman technique for crystal growth with growth rates ranging from 4-500 μm/s and a temperature gradient of 25 K/cm. It was determined that growth rates from 6.5-9.5 μm/s generated a cell morphology, where the lower limit corresponds to the plane front to cellular transition and the upper limit indicates the cellular to columnar dendrite transition. The microstructures of the alloys solidified from 30 μm/s to growth rates less than 500 μm/s were mainly composed of columnar dendrites, while the microstructures solidified at growth rates greater than 500 μm/s were equiaxed. Regarding experimental results on solute distribution, a prediction of the model developed by Rappaz and Boettinger for dendrite solidification of multicomponent alloys was applied with excellent agreement. Results of solute distribution were employed to derive the precipitation fraction of τ-phase needed to increase the electrochemical properties of the alloy to be used as an Al-sacrificial anode.

关键词： aluminum alloy unidirectional solidification growth rate solute distribution dendrite growth model

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Dual Zariski Spaces of Modules

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Algebra Colloquium 2023年第4期30卷 569-584页

作者： seçilÇeken Department of Mathematics Trakya UniversityEdirneTurkey

Let R be a commutative ring with identity,M be an R-module,L(M)denote the set of all submodules of M and g■(M)\{OM}.For any submodule N of M,we set gV^(d)(N)={K∈g:K■N}and gζ^(d)(M)=(GV^(d)(N):N■L(M)).Consider χ■L(R)\{R},where L(R)is the set of all ideals of *** set χV(I)=(j∈x:I■j)and χζ(R)={xV(I):I■L(R)}for any ideal I of *** this paper,we investigate when,for arbitrary χ and g as above,χζ(R)and gζ^(d)(M)form a topology and a semimodule,*** investigate the structure of gζ^(d)(M)in the case that it is a semimodule.

关键词： dual Zariski semimodule χ-Zariski semiring ·-coprime submodule subtractive subspace

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Evaluation of the ability of arsenic species to traverse cell membranes by simple diffusion using octanol-water and liposome-water partition coefficients

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journal of Environmental Sciences 2016年第11期28卷 222-232页

作者： Teresa chavez-Capilla William Maher Tamsin Kelly Simon Foster Ecochemistry Laboratory Institute for Applied Ecology University of Canberra Canberra ACT 2601 Australia National Centre for Forensic Studies Faculty of Education Science Technology and Mathematics University of Canberra CanberraACT 2601 Australia

Arsenic metabolism in living organisms is dependent on the ability of different arsenic species to traverse biological membranes. Simple diffusion provides an alternative influx and efflux route to mediated transport mechanisms that can increase the amount of arsenic available for metabolism in cells. Using octanol-water and liposome-water partition coefficients, the ability of arsenous acid, arsenate, methylarsonate, dimethylarsinate, thio-methylarsonate, thiodimethylarsinic acid, arsenotriglutathione and monomethylarsonic diglutathione to diffuse through the lipid bilayer of cell membranes was investigated. Molecular modelling of arsenic species was used to explain the results. All arsenic species with the exception of arsenate, methylarsonate and thio-methylarsonate were able to diffuse through the lipid bilayer of liposomes, with liposome-water partition coefficients between 0.04 and 0.13. Trivalent arsenic species and thio-pentavalent arsenic species showed higher partition coefficients, suggesting that they can easily traverse cell membranes by passive simple diffusion. Given the higher toxicity of these species compared to oxo-pentavalent arsenic species, this study provides evidence supporting the risk associated with human exposure to trivalent and thio-arsenic species.

关键词： ArsenicLiposomesPartition coefficientsPassive simple diffusionTrivalent arsenic speciesThio-arsenic species

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Effects of yttria content on the CMAS infiltration resistance of yttria stabilized thermal barrier coatings system

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journal of Materials Science & Technology 2020年第8期36卷 74-83页

作者： juan jGomez chavez Ravisankar Naraparaju Peter Mechnich Klemens Kelm Uwe Schulz C.V.Ramana University of Texas at El Paso Department of Mechanical EngineeringEl PasoTX79968USA German Aerospace Center(DLR) Institute of Materials ResearchCologne51170Germany

The effects of YO(1.5)doping in yttria-zirconia based thermal barrier coatings(TBCs)against CMAS interaction/infiltration are *** TBCs with an YO(1.5)content ranging from 43–67 mol.%(balance Zr O2)were produced by electron beam physical vapor deposition(EB-PVD)*** results reveal a trend of higher apatite formation probability with the higher free YO(1.5)available in the yttriazirconia ***,the infiltration resistance and amount of consumed coating appears to be strongly dependent on the YO(1.5)content in the *** thinnest reaction layer and lowest infiltration was found for the highest produced 67 YO(1.5)*** XRD experiments with volcanic ash/YO(1.5)powder mixtures with higher yttria contents than in the coatings(80 YO(1.5)and pure YO(1.5))also showed higher apatite formation with respect to increasing yttria *** threshold composition to promote apatite-based reaction products was found to be around 50 YO(1.5)in zirconia which was proved in the coatings and XRD powder *** YO(1.5)-ZrO2-Fe O-TiO2 bearing zirconolite-type phase was formed as a reaction product for all the coating compositions which implicates that TiO2 in the melt acts as a trigger for zirconolite *** phase could be detrimental for CMAS/volcanic ash infiltration resistance since it can be formed alongside with apatite which controls or limits the amount of Y^(3+)available for glass *** Fe rich garnet phase containing all the possible elements exhibited a slower nucleation compared to apatite and its growth was enhanced with slow cooling *** implications of phase stability and heat treatment effects on the reaction products are discussed for tests performed at 1250°C.

关键词： CMAS Volcanic ash Infiltration Electron beam physical vapor deposition Thermal barrier coating

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Theoretical insights of the pharmaceutical compound fluoxetine in water:Role in direct photolysis and indirect photolysis by free radicals

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journal of Environmental Sciences 2024年第8期142卷 269-278页

作者： Ying Lu se Wang Yifan Shen School of Environmental Science and Engineering Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologyJiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution ControlNanjing University of Information Science and TechnologyNanjing 210044China

The frequent detection of pharmaceutical compounds in the environment has led to a growing awareness,which may pose a major threat to the aquatic *** this study,photodegradation(direct and indirect photolysis)of two different dissociation states of fluoxetine(FLU)was investigated in water,mainly including the determination of photolytic transition states and products,and the mechanisms of indirect photodegradation with·OH,CO_(3)^(*-)and NO_(3)^(*).The main direct photolysis pathways are defluorination and C–C bond *** addition,the indirect photodegradation of FLU in water is mainly through the reactions with·OH and NO_(3)^(*),and the photodegradation reaction with CO_(3)^(*-)is relatively difficult to occur in the water *** results provide a theoretical basis for understanding the phototransformation process of FLU in the water environment and assessing its potential risk.

关键词： Fluoxetine Photochemical mechanism Direct photolysis Free radical reaction DFT

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The clip cage conundrum: Assessing the interplay of confinement method and aphid genotype in fitness studies

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Insect Science 2024年第5期31卷 1591-1602页

作者： Laura Marcela Martinez-chavez joe M.Roberts Alison j.Karley Bethan Shaw Tom W.Pope Centre for Crop and Environmental Science Agriculture and Environment DepartmentHarper Adams UniversityNewportShropshireUK Ecological Sciences The James Hutton InstituteInvergowrieDundeeUK Pest and Pathogen Ecology NIABEast MallingKentUK

Behavior and fitness are important ecological traits frequently measured in insect bioassays.A common method to measure them in soft-bodied herbivorous insects involves confining individuals to plant leaves using clip *** studies have pre-viously highlighted the negative effects of clip cages on leaf physiology,little is known about the impact that using this confinement method has on insect *** responses of different aphid genotypes/clones to different containment methods have not previously been *** we measured key fitness traits(intrinsic rate of natural increase,mean relative growth rate,time to reach reproductive adulthood and population doubling time)in the potato aphid,Macrosiphum euphorbiae Thomas(Hemiptera:Aphididae),when confined to plants using two methods:(1)clip cages to confine aphids to individual strawberry leaves and(2)a mesh bag to confine aphids to whole strawberry *** study identified a strong negative impact on all the measured aphid fitness traits when using clip cages instead of mesh *** also identified genotype-specific differences in response to confinement method,where clip cage confinement differentially affected the fitness of a given aphid genotype compared to the same genotype on whole *** results suggest that clip cage use should be carefully considered when experiments seek to quantify insect fitness and that whole plants should be used wherever *** the prevalence of clip cage use in insect bioassays,our results highlight the need for cau-tion when interpreting the existing literature as confinement method significantly impacts aphid fitness depending on their genotype.

关键词： aphid clonal variation aphid fitness clip cages confinement method feed-ing site insect bioassays

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Prey availability, prey selection, and trophic niche width in the lizard Psammodromus algirus along an elevational gradient

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Current Zoology 2018年第5期64卷 603-613页

作者： Gregorio MORENO-RUEDA Elena MELERO senda REGUERA Francisco j, ZAMORA-CAMACHO Ines alvarez-BENITO Departamento de Zoologla Facultad de Ciencias Universidad de Granada Granada E-18071 Spain Departamento de Biogeografia y Carnbio Global Museo Nacional de Ciencias Naturales-CSIC C/Jose Gutierrez Abascal 2 E-28006 Madrid Spain

Mountains imply enormous environmental variation, with alpine habitats entailing harsh environ- ments, especially for ectotherms such as lizards. This environmental variability also may imply variation in prey availability. However, little is known about how lizard trophic ecology varies with elevation. In this study, we analyze diet, prey availability, prey selection, and trophic niche width in the lacertid lizard Psammodromus algirus along a 2,200-m elevational gradient in the Sierra Nevada （se Spain）. The analysis of fecal samples has shown that Orthoptera, Formicidae, Hemiptera, Coleoptera, and Araneae are the main prey, although, according to their abundance in pitfall traps, Formicidae and Coleoptera are rejected by the lizard whereas Orthoptera, Hemiptera, and Araneae are preferred. Prey abundance and diversity increase with elevation and diet subtly varies along with the elevational gradient. The consumption of Coleoptera increases with elevation probably as a consequence of the lizard foraging more in open areas while basking. The electivity for Araneae increases with elevation. Araneae are rejected in the lowlands--where they are rela- tively abundant--whereas, at high elevation, this lizard positively selects them, despite they being less abundant. The lizard trophic niche width expands with elevation due to concomitant greater prey diversity and hence this lizard feeds on more prey types in highlands. Although no sex difference in diet has been found, the trophic niche is broader in females than males. As a whole, alpine lizards show a trophic niche simitar to that found at lower elevat（ons, suggesting that P. algirus is well adapted to the harsh environment found in alpine areas.

关键词： alpine habitats arthropods mountain ecology niche variation hypothesis trophic ecology

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Direct ink writing of polycaprolactone/polyethylene oxide based 3D constructs

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Progress in Natural Science:Materials International 2021年第2期31卷 180-191页

作者： Bin Zhang se Hun Chung Susan Barker Duncan Craig Roger j.Narayan jie Huang Department of Mechanical Engineering University College London Medway School of Pharmacy Universities of Greenwich and Kent School of Pharmacy University College London joint Department of Biomedical Engineering University of North Carolina and North Carolina State University

There has been increasing interest over recent years in the application of three-dimensional(3 D) printing technologies in the biomedical field. One such method is Direct Ink Writing(DIW); this approach has the potential advantage of allowing room-temperature deposition of materials, presented as an ink, to build complex architectures. DIW offers the ability to process biomaterials containing temperature-sensitive components. Due to the fabrication principles of DIW, there are specific rheological requirements that the ink must exhibit for the 3 D construction. For this reason, hydrogel-based liquid feed stocks have been the focal point of ink development. As a consequence, studies based on inks comprising hydrophobic biomaterials, which are insoluble in water and hence unsuited to the hydrogel approach, have been *** this study, we investigate novel inks that utilize polycaprolactone(PCL), a hydrophobic polymer, as the primary constituent by dissolving the polymer in solvent systems based on dichloromethane(DCM) and acetone(ACE). Moreover, polyethylene oxide(PEO) was incorporated into the PCL systems in order to extend the range of hydrophilicity of the systems. The rheological properties of the inks were investigated as a function of polymer composition and solvent system. Woodpile constructs of PCL and PCL/PEO were fabricated using DIW method and were assessed by a series of material characterisation. The type of solvent system had a noticeable impact on the ink rheology, which ultimately affected the surface properties. The incorporation of PEO particularly enhanced the roughness and wettability of the constructs. Our results support the use of DIW as a new means to process hydrophobic polymers for biomedical applications.

关键词： Direct ink writing Polycaprolactone Polyethylene oxide Ink rheology Material characterisation 3D construct

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