Importance of the irradiation timing within a chemoradiotherapy sequence including cisplatin and 5-FU-folinic acid. Experimental results

The objective of the present in vitro study was to determine an optimal timing of the irradiation in the combination cisplatin (CDDP) and 5-fluorouracil-folinic-acid (5-FU-FA) allowing a maximal cytotoxic effect on a human cell line derived from a head and neck carcinoma (CAL 27 cells). The various tested chemoradiotherapy sequences were applied in parallel to human keratinocytes in culture (SVK 14 cells). This was done in order to define the best sequence allowing the achievement of an optimal selectivity of the cytotoxic effects. The drug sequence was: CDDP over 2 h then fresh medium was added including the tandem 5-FU-d,I FA applied 6 h after CDDP, for 5 days. Irradiation was applied only once and at various times within the drug sequence. The cytotoxicity effects of the different chemoradiotherapy combinations were assessed by the MTT semi-automated test. The part taken by the 5-FU-FA combinations in the overall cytotoxicity was examined; an effect was apparent on CAL 27 cells only. The evolution of the radiation effect (RE = cell survival after drugs/cell survival after drugs plus irradiation) was analysed as a function of the different times of irradiation within the given drug sequence. Clearly, the RE values were dependent upon time at which the radiation dose in the chemoradiotherapy regimen was administered. For CAL 27 cells, irradiation effects were maximal at the first irradiation time tested after the end of the CDDP exposure (i.e. t = 3.5 h). In contrast, this optimal chemoradiotherapy timing for better cytotoxicity on CAL 27 cells did not correspond to that of SVK 14 cells. Consequently, it was possible to establish that the best time for the selectivity index was located shortly after the CDDP exposure.     

Bioresorbable and bioactive polymer/Bioglass® composites with tailored pore structure for tissue engineering applications

An overview about the development of porous bioresorbable composite materials for applications as scaffolds in tissue engineering is presented. A thermally induced phase separation method was developed to fabricate porous foam-like structures of poly(lactide-co-glycolide) (PLGA) containing bioactive glass particle additions (up to 50 wt.%) and exhibiting well-defined, oriented and interconnected porosity. The in vitro bioactivity and the degradability of the composite foams were investigated in contact with phosphate buffer saline (PBS). Weight loss, water absorption and molecular weight measurements were used to monitor the polymer degradation after incubation periods of up to 7 weeks in PBS. It was found that the presence of bioactive glass retards the polymer degradation rate for the time period investigated. The present results show a way of controlling the in vitro degradation behaviour of PLGA porous composite scaffolds by tailoring the concentration of bioactive glass.     

Self-awareness and other-awareness. II: Mirror self-recognition, social contingency awareness, and synchronic imitation.

Eighteen-month-old children were tested for mirror self-recognition using the classic rouge test or an alternative procedure, for social contingency awareness by being closely imitated for a long time, and for the capacity for communication by synchronic imitation. The classic mirror rouge test was shown to produce false negatives. Most recognizers and nonrecognizers became aware of being imitated and imitated the activity of a model, but only recognizers engaged in sustained synchronic imitation of the model. The results support our hypothesis that self-recognition and spontaneous perspective-taking develop in close synchrony because both require a capacity for secondary representation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Human Milk Antibodies against S1 and S2 Subunits from SARS-CoV-2, HCoV-OC43, and HCoV-229E in Mothers with a Confirmed COVID-19 PCR,Viral SYMPTOMS,and Unexposed Mothers

Background: Preexisting immunity to SARS-CoV-2 could be related to cross-reactive antibodies to common human-coronaviruses (HCoVs). This study aimed to evaluate whether human milk antibodies against to S1 and S2 subunits SARS-CoV-2 are cross-reactive to S1 and S2 subunits HCoV-OC43 and HCoV-229E in mothers with a confirmed COVID-19 PCR test, in mothers with previous viral symptoms during COVID-19 pandemic, and in unexposed mothers; Methods: The levels of secretory IgA (SIgA)/IgA, secretory IgM (SIgM)/IgM, and IgG specific to S1 and S2 SARS-CoV-2, and reactive to S1 + S2 HCoV-OC43, and HCoV-229E were measured in milk from 7 mothers with a confirmed COVID-19 PCR test, 20 mothers with viral symptoms, and unexposed mothers (6 Ctl1-2018 and 16 Ctl2-2018) using ELISA; Results: The S2 SARS-CoV-2 IgG levels were higher in the COVID-19 PCR (p = 0.014) and viral symptom (p = 0.040) groups than in the Ctl1-2018 group. We detected a higher number of positive correlations between the antigens and secretory antibodies in the COVID-19 PCR group than in the viral symptom and Ctl-2018 groups. S1 + S2 HCoV-OC43-reactive IgG was higher in the COVID-19 group than in the control group (p = 0.002) but did not differ for the other antibodies; Conclusions: Mothers with a confirmed COVID-19 PCR and mothers with previous viral symptoms had preexisting human milk antibodies against S2 subunit SARS-CoV-2. Human milk IgG were more specific to S2 subunit SARS-CoV-2 than other antibodies, whereas SIgA and SIgM were polyreactive and cross-reactive to S1 or S2 subunit SARS-CoV-2.     

Rheology of Zirconia Suspensions in a Nonpolar Organic Medium

Three dispersants (stearic acid, oleic acid, and poly(12-hydroxystearic acid)) are compared for their ability to produce low-viscosity suspensions of zirconia in kerosene. Rheological measurements and sediment packing density measurements show that poly(12-hydroxystearic acid) is a better dispersant than stearic acid or oleic acid; this is explained in terms of the longer tail of the poly(12-hydroxystearic acid) surfactant molecule. The amount of dispersant can be optimized to reduce viscosity and yield point of the suspension, and to eliminate thixotropic hysteresis. The use of a dispersion medium of lower viscosity than the dispersant makes it easy to detect when complete monolayer coverage has been achieved. The loss of pseudoplasticity, brought about by a higher degree of deflocculation, can be recovered by increasing the volume fraction of solids of a suspension and this is beneficial in the plastic forming of ceramics. Rheological measurements showed that these suspensions reach a "critical state" above a critical shear stress (τ_c). This critical state is described by several parameters, i.e., the Bingham yield stress (τ_b), the plastic viscosity (ν_Pl), and the critical shear rate (γ_c), which are dependent on the volume fraction of solids.     

Pressure-infiltration processing of reinforced aluminum

Pressure infiltration of liquid metal is one of the most important processing routes for the production of aluminum-matrix composites having a self-supporting reinforcement phase. This article briefly examines the physical phenomena governing infiltration processes, to present practical guidelines derived from their analysis for optimization of the process and the materials produced. Engineering aspects that are pertinent to infiltration techniques, including preform preparation, process configurations, flow control, and innovative processes, are summarized.     

基于分块技术的相位展开算法

对干涉相位图的相位展开是干涉合成孔径雷达处理过程中的重要步骤,也是干涉合成 孔径雷达理论与应用研究的难点所在.在充分利用干涉相位图中的干涉条纹信息的基础上,提出 了一种基于分块技术的相位展开算法.首先对干涉相位图做了分块处理,块是由干涉条纹线和图 像边界线组成的一个封闭的区域,在一个块内不存在相位跳跃,即在块内的相位展开已经完成. 在下一步对全图做相位展开时,再逐块进行.最后通过后处理技术进行错误校正.通过对真实数 据的实验和与传统方法的比较,证实了算法的有效性和稳定性．     

Free radical polymerization of ethyl methacrylate and ethyl α-hydroxy methacrylate: A computational approach to the propagation kinetics

The propagation kinetics of ethyl methacrylate (EMA) and ethyl α-hydroxy methacrylate (EHMA) has been subject to a computational study to understand their free radical polymerization (FRP) behavior in bulk and in solution using Density Functional Theory (DFT). The propagation of EHMA is studied in ethanol and toluene to assess the effect of hydrogen-bonding solvents on FRP of monomers with α-hydroxy functionality. Although EMA and EHMA resemble each other in structure, EHMA propagates faster in bulk due to the presence of intermolecular hydrogen-bonds, which tend to facilitate the approach of the propagating species. This falls in contrast with the experimentally observed lower propagation rates of EHMA in ethanol compared to toluene. Calculations show that the 2.28 rate acceleration in toluene is governed by the ratio of the pre-exponential factors, which reflect the entropies of activation, in both media. The polar protic solvent ethanol has a disruptive effect via hydrogen-bonding on the 6-membered ring shape of EHMA monomers thus decreasing the entropy of activation of the reaction. In the case of toluene, there are no special interactions with the hydrophobic solvent, the entropy of activation is higher than in ethanol.     

Agarose-based hydrogel as an electrografting cell

An agarose gel was used as an electrochemical cell to graft vinylic polymer layers on conductive surfaces by electro-initiated radical electrografting of various water-soluble and hydrophobic vinylic monomers in the presence of diazonium ions. The process was followed by in situ electrochemical measurements and the resulting grafted layer was characterized by infrared (IRRAS) and photoelectron (XPS) spectroscopy. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Comparison of methods of differentiating between fresh and frozen–thawed fish or fillets

Freezing is an efficient way of storing fish. Objectively though, it is very hard to determine whether a fish has been previously frozen. Following an appraisal of various methods, we selected a physical determination (torrymeter), a physiological examination (eye lens) and three enzymatic assays (α‐glucosidase, β‐N‐acetylglucosaminidase and β‐hydroxyacyl‐CoA‐dehydrogenase) and applied them to three species: plaice (Pleuronectes platessa), whiting (Merlangus merlangus) and mackerel (Scomber scombrus). We also compared the results obtained following slow and rapid freezing and investigated how spoilage affects the torrymeter measurements and α‐glucosidase assay values. For whole fish the physical method using the torrymeter is a reliable indicator. For fish fillets we recommend the enzymatic method using the α‐glucosidase assay, which should be accompanied by measurement of the freshness to avoid confusing a frozen–thawed fish and a fish in an advanced stage of spoilage. The values noted for fresh and thawed whiting and plaice indicated cut‐off values of 0.15 for whiting and 0.5 for plaice, above which it can be asserted that the sample had been frozen. © 2002 Society of Chemical Industry