Quantifying Western blots: Pitfalls of densitometry

Although Western blots are frequently quantified, densitometry is not documented and appears to be based merely on traditions and guesswork. Confirming previous experience, none of 100 randomly selected and systematically scanned most recent papers provided sufficient information on how Western blot results were translated into statistical values. The importance of such information, however, becomes evident from our correlations of plasma erythropoietin values of various mammals determined using RIA and Western blot densitometry. Different common densitometry procedures applied to the identical Western blot revealed p‐values of these correlations ranging from 0.000013 to 0.76 reflecting the necessity of a scientifically sound basis for densitometry of Western blots. At present, the current lack of any definitions in densitometry opens the door to uncontrollable acquisition of any desired p‐value. Here we provide data that define what should be considered, what avoided and what documented when quantifying Western blots.     

Analysis of Lamb waves with Spectral Finite Elements

For the analysis of the elastic wave propagation at high frequencies, the spectral finite element method (SFEM) is under investigation. The SFEM uses high-order shape functions which are composed of Lagrange polynomials with nodes at the Gauss-Lobatto quadrature points. In this way we obtain a diagonal mass matrix which makes an explicit time scheme more efficient. In a numerical example a computation by Montjoie of an elastic wave propagation within a Reissner-Mindlin (RM) model is presented. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Voltage-gated sodium channels in taste bud cells

Background  

Taste bud cells transmit information regarding the contents of food from taste receptors embedded in apical microvilli to gustatory nerve fibers innervating basolateral membranes. In particular, taste cells depolarize, activate voltage-gated sodium channels, and fire action potentials in response to tastants. Initial cell depolarization is attributable to sodium influx through TRPM5 in sweet, bitter, and umami cells and an undetermined cation influx through an ion channel in sour cells expressing PKD2L1, a candidate sour taste receptor. The molecular identity of the voltage-gated sodium channels that sense depolarizing signals and subsequently initiate action potentials coding taste information to gustatory nerve fibers is unknown.     

Phosphonate metal–organic frameworks used as dye removal materials from wastewaters

A very intense study class of complex porous materials, metal–organic frameworks (MOFs), composed of diverse central metallic ions attached to organic linkers, was used in this study as adsorbant materials from wastewaters. Phosphonate MOFs were prepared by the reaction of divalent inorganic salts (CoSO₄ · 7H₂O, NiSO₄ · 6H₂O, CuSO₄ · 5H₂O,) with vinyl phosphonic acid in hydrothermal conditions, obtaining cobalt, nickel, and copper vinylphosphonate (CoVP, NiVP, and CuVP). During synthesis the experimental conditions were varied in terms of time, temperature, and pH. The synthesized materials were characterized by Fourier transform infrared, thermogravimetric analysis, scanning electron microscopy, and X-ray crystallography. The efficiency of MOFs as adsorbents was investigated for diverse initial dye concentrations at different pH values and at three temperatures (25, 40, and 55°C). The synthesized materials presented good efficiency in the elimination of anionic as well as cationic type of dyes from aqueous solutions. The highest adsorption capacities were obtained working at optimum solution pH 4.2 for Acid Orange 7 and 10 for Basic Fuchsine, using 1 g/L of MOFs at room temperature (25°C). The adsorption capacities increase in the following order: CuVP < NiVP < CoVP.     

Hydrogenation of Esters to Alcohols with a Well‐Defined Iron Complex

We present the first base‐free Fe‐catalyzed ester reduction applying molecular hydrogen. Without any additives, a variety of carboxylic acid esters and lactones were hydrogenated with high efficiency. Computations reveal an outer‐sphere mechanism involving simultaneous hydrogen transfer from the iron center and the ligand. This assumption is supported by NMR experiments.     

Drivers for Sun Protection in Black South Africans

Sun protection behavior studies are almost exclusively carried out in populations with fair skin for the obvious reason that people with unpigmented skin are more susceptible to the health impacts of excess solar ultraviolet radiation exposure. In a dataset of 1271 Black South Africans, we analyzed factors related to sun protection applied when spending time outdoors including awareness of skin cancer, gender, age and Living Standards Measure (LSM) where 1–4 equate to the lowest, 5–7 intermediate and 8–10 the highest LSM status. The most important driver for Black South Africans to use sun protection was whether they were aware of skin cancer (OR: 2.6 for those who were aware versus those who were not, P < 0.0001). Sunscreen was preferred by respondents in LSM 8-10 whereas people in the lowest group (LSM 1-4) favored shade, umbrellas and hats. One in two respondents claimed to use some form of sun protection, which appears to be higher than deeply pigmented populations in other countries.