适用于光学显微镜的细胞培养芯片

虽然细胞分子生物学近年来发展很快,但是细胞培养的方法变化很慢.将近一个世纪以前发明的有盖培养皿至今仍在常规使用,但它已经不适合许多用来观察和分析活体细胞内发生的变化的现代光学分析方法.这篇文章描述了一种细胞培养芯片装置,它能有效地用于细胞培养和随后的高端光学分析,比如荧光和共焦显微镜方法.     

Surface area production during grinding

During grinding, in cascading mills, the mass distribution of the material moves continuously to finer sizes. Grinding models are usually designed to predict the size distribution of the mill products either as a function of effective breakage events and the time or the energy consumed by the mill. Mill products are always tested for their size analysis and their fineness is usually expressed as the size d through which a certain amount of material passes, i.e. d₈₀. However, particulate materials have some supplementary properties that a grinding model should predict as well. The specific surface area is such an important supplementary property. Initially, the present work examines the relationship between mass distribution and the surface area of ground materials and determines the conditions under which, mass distribution can be used to determine the surface area. Based on these findings the work further examines the operating conditions of a cascading mill under which the surface area of the material increases at the highest rate. The operating parameter examined is the mill load ratio expressed as the mass ratio of mill grinding media and the material present in the mill.     

Physicochemical properties and silicon content in wheat flour treated with diatomaceous earth and conventionally stored

This study was done to evaluate the physicochemical properties and to quantify the residual silicon in flour from wheat grains treated with different dosages of DE and stored in a conventional system for 180 days. Samples containing 10.0 kg of wheat grain were treated with 0.00, 2.00 and 4.00 g kg⁻¹ of DE and then homogenized and stored in cotton bags at 22 °C and 70 ± 5 g 100 g⁻¹ relative humidity. Physicochemical analyses were carried out at 0, 60, 120 and 180 days of storage. The experiment was conducted in a randomized design with a factorial 3 × 4 arrangement (three doses of DE × four storage periods), totaling 12 treatments, with three replicates for each treatment. The wheat flour samples were digested and the silicon residue quantification was conducted through colorimetry. The wheat treated with DE presented a lower test weight compared with control, +b^∗ chromaticity coordinate for color and increased ash content and L^∗. The physicochemical changes in the grain and wheat flour were proportional to the amount of DE applied.     

Estimation of the total uncertainty of sky-radiance measurements in field experimental conditions: implications for the aerosol single-scattering albedo

We compare the spectral sky radiance measured by three ground-based optical radiometers during the second Aerosol Characterization Experiment (ACE-2) to estimate the total uncertainty of the radiance in field experimental conditions. The propagation of this uncertainty on the column-integrated aerosol single-scattering albedo omega0 at 868 nm is investigated. The radiance measurements are affected by a systematic gain uncertainty of less than 2% in the visible spectral region and within 6% in the near-IR region. Correcting the measured radiance by a systematic uncertainty reduces the dispersion of the omega0 from 0.07 to 0.03. Besides, the total relative uncertainty of the radiance measurements in field experimental conditions is within 4% at any wavelength. The corresponding uncertainty delta omega0 is 4% for an aerosol optical thickness of 0.2.     

BMP regulates vegetal pole induction centres in early xenopus development

BACKGROUND: Bone morphogenetic protein (BMP) plays an important role in mesoderm patterning in Xenopus. The ectopic expression of BMP-4 protein hyperventralizes embryos, whereas embryos expressing a BMP-2/4 dominant-negative receptor (DNR) are hyperdorsalized. Mesoderm is initially induced in the marginal zone by cells in the underlying vegetal pole. While much is known about BMP's expression and role in patterning the marginal zone, little is known about its early role in regulating vegetal mesoderm induction centre formation. RESULTS: The role of BMP in regulating formation of vegetal mesoderm inducing centres during early Xenopus development was examined. Ectopic BMP-4 expression in vegetal pole cells inhibited dorsal mesoderm induction but increased ventral mesoderm induction when recombined with animal cap ectoderm in Nieuwkoop explants. 32-cell embryos injected with BMP-4 RNA in the most vegetal blastomere tier were not hyperdorsalized by LiCl treatment. The ectopic expression of Smad or Mix.1 proteins in the vegetal pole also inhibited dorsal mesoderm induction in explants and embryos. Expression of the BMP 2/4 DNR in the vegetal pole increased dorsal mesoderm induction and inhibited ventral mesoderm induction in explants and embryos. CONCLUSIONS: These results support a role for BMP signalling in regulating ventral vegetal and dorsal vegetal mesoderm induction centre formation during early Xenopus development.     

Circumferential pharyngolaryngectomy with total esophagectomy for locally advanced carcinomas

In 1996, 20 of 21 patients with mucosal leishmaniasis, treated in 1994 with aminosidine sulfate, 16mg/kg/day salt, by intramuscular injection for 20 days, were clinically evaluated. One patient died due to disease not related to mucosal leishmaniasis. Seven of 14 patients (66.7% N = 21) who achieved complete remission three months after treatment remained clinically cured 24 months later and seven relapsed in the same period (50% N = 14). Sorological follow-up showed poor correlation with the results of clinical examination.     

On Barenblatt's problem

The problem of flow in media with double porosity (e.g. fissured rocks) is considered by utilizing the author's concept of “multiporosity” and employing the apparatus of continuum theory of mixtures. Relevant results obtained by Barenblatt et al. within the Russian literature are shown to be contained in the present theory.