Bovine adrenals and hypothalamus are a major source of proscillaridin A- and ouabain-immunoreactivities

Besides an isomer of the cardenolide ouabain, a material with a similar HPLC retention time as ouabain but cross-reactivating with antibodies against the bufadienolide proscillaridin A and inhibiting the sodium pump is known to circulate in human blood plasma (B. SICH et al., Hypertension 27, 1073-1078 (1996).). The concentrations of both substances are known to correlate with the blood pressure. It was the intention of this work to localize tissues that contain the highest concentrations of the proscillaridin A immunoreactive material, to correlate its concentration with that of ouabain and to get information whether the concentration of this material simply reflects the number of sodium pumps of the tissue extracted. Specific antibodies for each cardiotonic steroid were used to test the tissue concentration. This report shows that in bovine tissues the distribution pattern of proscillaridin A and ouabain immunoreactivities are similar and that hypothalamus and adrenals show the highest concentrations. The cross-reactive material did not reflect the number of sodium pumps per g of wet weight tissue as measured by [3H]ouabain binding. Therefore, it is unlikely that the tissue concentrations in both immunoreactivities reflects the tissue capacity of sodium pumps labeled with cardiotonic steroids via the blood plasma. The study rather favors the concept that two different types of inhibitors of the sodium pump exist within both tissues.     

Reconstitution of ciliary membranes containing tubulin

Membranes from the gill cilia of the mollusc Aequipecten irradians may be solubilized readily with Nonidet P-40. When the detergent is removed from the solution by adsorption to polystyrene beads, the proteins of the extract remain soluble. However, when the solution is frozen and thawed, nearly all of the proteins reassociate to form membrane vesicles, recruiting lipids from the medium. The membranes equilibrate as a narrow band (d = 1.167 g/cm3) upon sucrose density gradient centrifugation. The lipid composition of reconstituted membranes (1:2 cholesterol:phospholipids) closely resembles that of the original extract, as does the protein content (45%). Ciliary calmodulin is the major extract protein that does not associate with the reconstituted membrane, even in the presence of 1 mM calcium ions, suggesting that it is a soluble matrix component. The major protein of reconstituted vesicles is membrane tubulin, shown previously to differ hydrophobically from axonemal tubulin. The tubulin is tightly associated with the membrane since extraction with 1 mM iodide or thiocyanate leaves a vesicle fraction whose protein composition and bouyant density are unchanged. Subjecting the detergent-free membrane extract to a freeze-thaw cycle in the presence of elasmobranch brain tubulin or forming membranes by warming the extract in the presence of polymerization-competent tubulin yields a membrane fraction with little incorporated brain tubulin. This suggests that ciliary membrane tubulin specifically associates with lipids, whereas brain tubulin preferentially forms microtubules.     

Partially imidized,water-soluble polymeric amides. I. Partially imidized polyacrylamide and polymethacrylamide

Five to six million molecular weight polyacrylamide and polymethacrylamides of comparable post-alkaline hydrolysis viscosities were imidized by dissolution and heating in 6N HCl. After alkaline hydrolysis, the imidized polymers demonstrated significantly better retention of viscosity to 2% NaCl than did similar partially hydrolyzed polymers. Viscosities in 0.01% NaCl and resistance to shear were not markedly affected by this modification. It is assumed that this improved performance in brine is the result of chain stiffening due to intrachain imide rings.     

赛买提大蒜中大蒜素的稳定性研究

文章研究了不同因素对大蒜素稳定性的影响,结果表明:大蒜素在pH为3~5时较稳定,在pH为8~11时稳定性比较差;大蒜素对热不稳定,尤其当温度高于100℃时;有机溶剂和调和油对大蒜素有稳定作用;糖类对大蒜素有一定的保护作用,尤以β-环糊精和可溶性淀粉的保护作用最佳;添加0.5%~1.0%的VC对大蒜素有保护作用,而当添加量大于1.5%时,大蒜素含量下降迅速。     

Identification of important image features for pork and turkey ham classification using colour and wavelet texture features and genetic selection

A method to discriminate between various grades of pork and turkey ham was developed using colour and wavelet texture features. Image analysis methods originally developed for predicting the palatability of beef were applied to rapidly identify the ham grade. With high quality digital images of 50–94 slices per ham it was possible to identify the greyscale that best expressed the differences between the various ham grades. The best 10 discriminating image features were then found with a genetic algorithm. Using the best 10 image features, simple linear discriminant analysis models produced 100% correct classifications for both pork and turkey on both calibration and validation sets.     

Predicting Subcutaneous Glucose Concentration in Humans: Data-Driven Glucose Modeling

The combination of predictive data-driven models with frequent glucose measurements may provide for an early warning of impending glucose excursions and proactive regulatory interventions for diabetes patients. However, from a modeling perspective, before the benefits of such a strategy can be attained, we must first be able to quantitatively characterize the behavior of the model coefficients as well as the model predictions as a function of prediction horizon. We need to determine if the model coefficients reflect viable physiologic dependencies of the individual glycemic measurements and whether the model is stable with respect to small changes in noise levels, leading to accurate near-future predictions with negligible time lag. We assessed the behavior of linear autoregressive data-driven models developed under three possible modeling scenarios, using continuous glucose measurements of nine subjects collected on a minute-by-minute basis for approximately 5 days. Simulation results indicated that stable and accurate models for near-future glycemic predictions (<60 min) with clinically acceptable time lags are attained only when the raw glucose measurements are smoothed and the model coefficients are regularized. This study provides a starting point for further needed investigations before real-time deployment can be considered.     

Triple wavelength LED driver for optical brain-computer interfaces

A dedicated triple wavelength LED driver is presented for optical brain?computer interfacing (BCI). The solution caters for the constraints of a common-anode grounded case and modulation up to several kilohertz that allows source separation of light that has backscattered from the brain. With total harmonic distortion of 0.95% and a frequency range of ∼40 kHz, the driver has application in a continuous wave optical BCI. Other modulation strategies such as time division multiplexing (TDM) are catered for, owing to input DC coupling. Linearity in the optical output is maintained by the 'load sensing' differential op-amp on the LED?s current limiting resistor, which is the basis for the V-I conversion.     

A novel chelate-assisted C−C bond formation on a Cd(II) complex of an asymmetric heptadentate(N7) tripodal Schiff base ligand

Cadmium(II) complexes of some potentially heptadentate tripodal Schiff base ligands with the general formula N{(CH₂)_nNCHC₅H₄N}₂{(CH₂)_mNCHC₅H₄N}) (where n = m = 2, L₂₂₂; n = 2, m = 3, L₃₂₂; n = 3, m = 2, L₃₃₂) have been studied. These ligands are products of the full condensation of a number of tripodal tetraamines with 2-pyridinecarboxaldehyde. An unusual reaction of an additional 2-pyridine-carboxaldehyde with a methylene group adjacent to the imine bond only during template preparation of [Cd(L₃₃₂)]²⁺ was observed. The latter reaction is a novel chelate-assisted C?C bond formation because it is occurred only where a rigid five-membered chelate ring is present.     

Surface remobilization of buoyancy-driven surfactant-laden drops at low reynolds and capillary numbers

It is well known that the terminal velocity of a drop settling in a viscous fluid is impacted by surface tension gradients. These gradients can develop because of nonuniform accumulation of surfactant on the surface as a result of a number of transport mechanisms. Here, a surfactant transport model based on a sorption-limited Frumkin framework is used to describe surfactant transport in the presence of both surface convection and diffusion at low Reynolds and capillary numbers. Constants characterizing surfactant transport in the Frumkin framework are experimentally determined and used to predict aqueous drop velocities with varying surfactant concentrations and volumes. Computation is carried out by satisfying equations governing mass, momentum, and interface species conservation. Experiments demonstrate qualitative and quantitative agreement between predicted and measured drop velocities. It is shown that surface remobilization explains some observed trends in measured velocity as the drop size decreases. © 2018 American Institute of Chemical Engineers AIChE J, 65: 294–304, 2019