Dialdehyde Starch Hydrazones: Preparation and Properties of Cationic Dispersions

Cationic dialdehyde starch (DAS) dispersions have been prepared in water at 15% concentration by a new cooking procedure. A stable fluid form of cationic DAS, a wet- and dry-strength agent for paper, should facilitate commercial use. Cationic DAS dispersions of pH 3.0 stored in polyethylene containers at 25°C or below were unchanged after 6 months; other storage conditions were also evaluated. An unexpected benefit of the new preparative conditions was a 40% reduction of cationizing agent, betaine hydrazide hydrochloride, without loss of effectiveness. Further savings may be possible by blending cationic DAS with unmodified starch; wet- and dry-strength improvements were maintained in paper with a blend containing 33% unmodified starch and 67% cationic DAS.     

采用单独碳化室压力调节系统减少焦炉排放

PROven(R)系统的开发为了减少焦炉的排放,过去已进行了多种技术的开发.但是从焦炉炉门、装料孔边缘等处逸散物的减少,已受到工艺技术的制约.一个基本的制约因素是,在集气总管内的压力和联接到总管的所有碳化室内的压力之间有着密不可分的关系.     

Expression of genes that contribute to proliferative and metastatic ability in breast cancer resected during various menstrual phases

BACKGROUND: Retrospective studies show significant improvements in survival among women who had breast cancer resected during the luteal phase of their menstrual cycle compared with the follicular phase. We hypothesised that tumour tissue would show cyclical changes in expression of genes whose products might contribute to metastatic potential. METHODS: We studied 32 premenopausal women with operable breast cancer. We assayed hormones to define more accurately the menstrual phase during which surgery was done. We used northern blot analysis of RNA from fresh-frozen tumour specimens to study the patterns of expression of genes for proteolytic enzymes (cysteine proteinase cathepsin L and aspartyl proteinase cathepsin D; matrix metalloproteinases MMP-9 and MMP-2), tissue inhibitors of metalloproteinases TIMP-1 and TIMP-2, and TP53. RESULTS: There was a significantly higher level of expression of RNA for cathepsin L, MMP-9, and TP53 (p=0.005, 0.03, 0.03, respectively) in tumours that were resected during the follicular and periovulatory phases of the menstrual cycle than at other times in the cycle. A similar but non-significant trend was seen for MMP-2 and cathepsin D. A non-significant trend in the opposite direction was seen for TIMP-1 and TIMP-2. INTERPRETATION: We found that tumour expression of genes that may contribute to proliferative capacity and metastatic potential can change in breast cancer during the course of the menstrual cycle. The finding could provide a molecular explanation for the reports of improved survival in some breast-cancer patients whose tumours were removed during the luteal phase of the menstrual cycle. Larger studies are required to extend our study, assess mechanisms of gene regulation, and verify any relevant influence in long-term survival.     

Identification of beta-L-gulose as the sugar moiety of the main polar lipid Thermoplasma acidophilum

We studied the antibody binding capacity (ABC) of various cell-surface antigens in normal human fetuses and term neonates on lymphocyte, monocyte, and polymorphonuclear (PMN) cells by quantitative flow cytometry also designated by quantimetry. Analysis of changes of expression level on these leukocytes during the developmental process was also investigated. The results indicated that the ABC values of most studied markers change during the maturational process. The ABC of lymphocyte-associated antigens studied such as CD5 and CD7 showed only a decrease from fetus to adult, whereas according to the type of molecule on monocyte and PMN there was either an increase or a decrease of ABC values dependent on the stage of the developmental process, from fetus to neonate or from neonate to adult. However, the ABC values of leukocyte membrane antigens such as CD16, CD46, and CD55 on all leukocytes and CD11b, CD11c, and CD35 on myeloid cells did not change. Their expression level was already mature in fetuses compared with adult cells. In addition, in this quantimetric approach, the analysis of the results for CD11a and CD8 suggested that the changes of CD11a expression level on lymphocyte subsets can depend on one mechanism, whereas there are probably at least two for CD8. Furthermore, the expression patterns of CD5, CD7, and CD11a change during maturation. We concluded that, even if the neonate response pattern to immunological challenge differs from an adult and this is based primarily on the relative numbers and functional activity of lymphocyte T subsets (especially TH1/TH2) and their cytokine profiles, these quantitative and qualitative phenotypical differences might also contribute to explain the functional peculiarities of leukocyte fetal and cord blood cells. All these findings support the notion of immaturity and maturity of ABC expression.     

Isotope effect in the binding of tritium and 14C-labelled cortisol to corticosteroid-binding-globulin in serum

We have determined the free cortisol concentration in serum using either the Amicon MPS-1 ultrafiltration-centrifugation method (I) or equilibrium dialysis (II). If procedure I was used we found that [1,2,6,7-3H]-, and [4-14C]cortisol had a lower affinity than unlabelled cortisol for corticosteroid binding globulin (CBG). The binding affinity (Ka) to three separate CBG-containing samples was 8-18 times lower for [1,2,6,7-3H]cortisol and 30-90 times lower for [4-14C]cortisol, when compared with that of unlabelled cortisol. This difference in affinity to CBG was not observed if method II was used for the free cortisol determinations. The observed isotope effect in method I is not caused by unspecific binding to material such as the Amicon MPS-1 chamber or to impurities in the tracer. We suggest that the centrifugation step during ultrafiltration changed the conformation of CBG, thereby reducing its affinity for labelled cortisol. It is concluded that incorrect results will be obtained if radiolabelled is cortisol used for determining the free cortisol content of plasma with the Amicon MPS-1 device.     

Easily made and handled carbon nanocones for scanning tunneling microscopy and electroanalysis

Well-formed carbon nanocones at the ends of micrometer-diameter carbon fibers (CFs) were fashioned into functional tips for scanning tunneling microscopy (STM) and miniaturized voltammetric sensors. Sharpening of single graphite filaments was achieved by simple DC electrochemical etching in 0.1 N NaOH. Operated as STM tips, pointed CFs resolved in air the contour and surface morphology of a nanoscopic Au line pattern and imaged in vacuum a Si (1 1 1) surface with clear atomic resolution. Subjecting already etched CFs to tip-sparing insulation with electrodeposited paint produced conical carbon ultramicroelectrodes (UMEs) with effective radii down to about 900 nm. Comparative cyclic voltammetry trials in alkaline, neutral and acidic solutions showed that the conical carbon UME’s had a wider practical potential window for electroanalytic applications than, for instance, Pt disk UMEs. The CF-based conical sensors described here are exceptionally easy to make with simple laboratory equipment and perform well in STM topography imaging and voltammetry. The inherent simplicity of sensor production widens the field of potential users, and offers clear advantages over existing types of UMEs, in particular those based on carbon nanotubes, which are especially hard to handle in an optical microscope setting.     

Investigations of ductile damage during the process chains of toothed functional components manufactured by sheet-bulk metal forming

Sheet-bulk metal forming processes combine conventional sheet forming processes with bulk forming of sheet semi-finished parts. In these processes the sheets undergo complex forming histories. Due to in- and out-of-plane material flow and large accumulated plastic strains, the conventional failure prediction methods for sheet metal forming such as forming limit curve fall short. As a remedy, damage models can be applied to model damage evolution during those processes. In this study, damage evolution during the production of two different toothed components from DC04 steel is investigated. In both setups, a deep drawn cup is upset to form a circumferential gearing. However, the two final products have different dimensions and forming histories. Due to combined deep drawing and upsetting processes, the material flow on the cup walls is three-dimensional and non-proportional. In this study, the numerical and experimental investigations for those parts are presented and compared. Damage evolution in the process chains is simulated with a Lemaitre damage criterion. Microstructural analysis by scanning electron microscopy is performed in the regions with high mechanical loading. It is observed that the evolution of voids in terms of void volume fraction is strongly dependent on the deformation path. The comparison of simulation results with microstructural data shows that the void volume fraction decreases in the upsetting stage after an initial increase in the drawing stage. Moreover, the concurrent numerical and microstructural analysis provides evidence that the void volume fraction decreases during compression in sheet-bulk metal forming.     

Study of the vertical transport in <Emphasis Type="Italic">p</Emphasis>-doped superlattices based on group III-V semiconductors

The electrical conductivity σ has been calculated for p-doped GaAs/Al_0.3Ga_0.7As and cubic GaN/Al_0.3Ga_0.7N thin superlattices (SLs). The calculations are done within a self-consistent approach to the theory by means of a full six-band Luttinger-Kohn Hamiltonian, together with the Poisson equation in a plane wave representation, including exchange correlation effects within the local density approximation. It was also assumed that transport in the SL occurs through extended minibands states for each carrier, and the conductivity is calculated at zero temperature and in low-field ohmic limits by the quasi-chemical Boltzmann kinetic equation. It was shown that the particular minibands structure of the p-doped SLs leads to a plateau-like behavior in the conductivity as a function of the donor concentration and/or the Fermi level energy. In addition, it is shown that the Coulomb and exchange-correlation effects play an important role in these systems, since they determine the bending potential.     

Mapping the structure of a liquid spray by means of neural networks

This paper presents the results of a study aimed at mapping the structure of a liquid spray system along the spray cone. Experimental results obtained by phase-Doppler anemometry (PDA) consisted of the number distributions of droplet size, velocity, and interparticle arrival time at different locations within the spray cone. The experimental data were analyzed by means of multivariate statistical techniques, in order to identify different regimes in the spray. Neural network models (NN) were fitted to the experimental data, resulting in good agreement between experimental and calculated results for most locations within the spray cone. However, in some parts of the cone the agreement was poor, and the general trends could not be well predicted by the NN models. The mismatch is due to unsteady spray conditions or incomplete atomization (e.g. existence of non-spherical particles). This fact was adopted as a criterion to identify the regions where the spray is fully established, corresponding to the regions of the spray where PDA measurements can be successfully performed. This criterion has been applied along the spray cone for different operating conditions, and can be used as a tool to map the fluid dynamic characteristics in liquid sprays.