A multi-agent model describing self-renewal of differentiation effects on the blood cell population

In this work, a new multi-agent model is used to describe blood cell population dynamics. More particularly, we focus our simulations here on differentiation and self-renewal process based on cell communication. We consider the different cases where progenitor cells are able to self-renew or not in the bone marrow. As a consequence of this study, we give some possible explanations of the mechanism for recovery of the system under important blood loss or blood diseases such as anemia.     

Cell decomposition for P‐minimal fields

In [12], P. Scowcroft and L. van den Dries proved a cell decomposition theorem for p‐adically closed fields. We work here with the notion of P‐minimal fields defined by D. Haskell and D. Macpherson in [6]. We prove that a P‐minimal field K admits cell decomposition if and only if K has definable selection. A preprint version in French of this result appeared as a prepublication [8] (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Simultaneous measurement of the maximum oscillation amplitude and the transient decay time constant of the QCM reveals stiffness changes of the adlayer

Interpretation of adsorption kinetics measured with a quartz crystal microbalance (QCM) can be difficult for adlayers undergoing modification of their mechanical properties. We have studied the behavior of the oscillation amplitude, A₀, and the decay time constant, , of quartz during adsorption of proteins and cells, by use of a home-made QCM. We are able to measure simultaneously the frequency, f, the dissipation factor, D, the maximum amplitude, A₀, and the transient decay time constant, , every 300 ms in liquid, gaseous, or vacuum environments. This analysis enables adsorption and modification of liquid/mass properties to be distinguished. Moreover the surface coverage and the stiffness of the adlayer can be estimated. These improvements promise to increase the appeal of QCM methodology for any applications measuring intimate contact of a dynamic material with a solid surface.     

Vesicles in haptotaxis with hydrodynamical dissipation

We analyze the problem of vesicle migration in haptotaxis (a motion directed by an adhesion gradient), though most of the reasoning applies to chemotaxis as well as to a variety of driving forces. A brief account has been published on this topic [#!Cantat99a!#]. We present an extensive analysis of this problem and provide a basic discussion of most of the relevant processes of migration. The problem allows for an arbitrary shape evolution which is compatible with the full hydrodynamical flow in the Stokes limit. The problem is solved within the boundary integral formulation based on the Oseen tensor. For the sake of simplicity we confine ourselves to 2D flows in the numerical analysis. There are basically two regimes (i) the tense regime where the vesicle behaves as a “droplet” with an effective contact angle. In that case the migration velocity is given by the Stokes law. (ii) The flask regime where the vesicle has a significant (on the scale of the vesicle size) contact curvature. In that case we obtain a new migration law which substantially differs from the Stokes law. We develop general arguments in order to extract analytical laws of migration. These are in good agreement with the full numerical analysis. Finally we mention several important future issues and open questions. Received 24 June 2002 and Received in final form 4 February 2003 Published online: 16 April 2003 RID="a" ID="a"e-mail: isabelle.cantat@univ-rennes1.fr     

Immobilization of trichordema reesei by radiation polymerization

Immobilization of trichordema Reesei (QM9414) was prepared by radiation polymerization. It was found that the activity of fixed cells increased with inseasing surface area of the carrier and was affected by the concentration of monomer tetraethylenglycol dimethacrylate (4G) and the shape of the substrate composition and structure of cotton textile fabics.     

超声对细胞膜通透性的影响及应用

适当参数的超声，使细胞膜发生可以修复的损伤，使细胞膜的通透性提高，从而使细胞内的物流释放到细胞外，细胞外的物质进入细胞内，这一现象可以用于释放代谢产物或中间产物，基因转导，强化化学方法治疗肿瘤等方面。     

氢化物发生-原子荧光光谱法测定电池中的汞

本文介绍了氢化物发生-原子荧光光谱法定量分析电池中的汞，方法的回收率为97.3%-102.0%，精密度（RSD）为4.2%。适用于电池中汞的测定。     

Patterned assembly of Yarrowia lipolytica yeast cells onto thermally evaporated octadecylamine films

Thermally evaporated patterned films of the lipid, octadecylamine (ODA), have been used in the immobilization of the hydrocarbon-degrading cells, Yarrowia lipolytica. The immobilization of the yeast cells occurs on hydrophobic surfaces presented by the lipid film elements in the patterned structure, the attachment of the cells to the lipid film occurring possibly through hydrophobic interactions between the hydrocarbon chains of the fatty amine film and the cell wall of the yeasts. It is observed that the cell immobilization is extremely faithful to the underlying lipid template indicating potential use in tissue engineering as well as materials applications involving specific enzyme-based biotransformations.     

THE ANTISENSE C-HA-RAS OLIGODEOXY-NUCLEOTIDES INHIBIT THE PROLIFERATION OF THE GASTROCARCINOMA-DNA-TRANSFORMED RAT 3-3 CELLS AND REDUCE THE P21 EXPRESSION OF THE CELLS

The Rat 3-3 is a secondary transformant of the rat fibroblast cell line (Rat-1) transfectedwith total DNA of a gastrocarcinoma cell line BGC-823. The cells over-express the c-Ha-rasoncogene which contains point mutation at the 12th codon. In order to determine how theactivated c-Ha-ras oncogene expression governs the cell's transformation, two pendadecadeoxy-nucleotides AS-1 and AS-2 were synthesized. AS-1 was complementary to the single strandof the first three codons and the upstream sequence close to the ribosome binding site of c-Ha-ras mRNA. AS-2 was complementary to the 3' end of the first intron and the 5' end ofthe second exon of c-Ha-ras unripe RNA enclosed in the nucleus. The oligonucleotides couldblock either the translation of c-Ha-ras mRNA or the splicing of c-Ha-ras unripe RNA, thusinhibiting the expression of the activated c-Ha-ras oncogene and the proliferation of thetransformed cells Rat 3-3. The inhibitory effect increased with a growing concentration ofthe antisense oligodeoxynucleoti     

P-V-T properties of alternating poly(ethylene-propylene) liquids

The pressure-volume-temperature (P-V-T) properties of monodisperse alternating poly(ethylene-propylene) (hydrogenated polyisoprene) melts of varying molecular weights are measured at 0.1 MPa < P < 200.1 MPa, and 290 K < T < 510 K in a dilatometer-type apparatus. The Flory-Orwoll-Vrij (FOV), Modified Cell Model (MCM), Sanchez-Lacombe (SL), and the Statistical Associating Fluid Theory (SAFT) equations of state are found to correlate the experimental data with excellent accuracy, except either at low pressures and high temperatures, or at high pressures and low temperatures. On average, MCM and SAFT fit the data slightly better than FOV and SL. The equation-of-state parameters are found to be independent of molecular weight, especially for SAFT, as required by the theory. © 1994 John Wiley & Sons, Inc.