A rapid preparation technique for studying highly water-swollen membranes with a scanning electron microscope (SEM) supplied with a cryo-unit

In this study the cryo-unit is introduced as a new and useful instrument to investigate water-containing specimens with the SEM. Often water-containing biological specimens are studied, but in our case we used water-swollen polymer membranes. The results show that application of a cryo-unit permits the study of this material at low temperatures up to magnifications of about 10 000 times, while other techniques failed to give reproducible results

A preparation technique for examination of wet-spun polymer fibers in a scanning electron microscope

In this paper the technique is discussed of sample preparation for freshly wet-spun polymer fibers, to be examined by scanning electron microscopy.\ud It makes use of cryogenic breaking of the samples, followed by freeze drying or freeze-etching of the specimen and coating it with a charge conducting layer.\ud The method can also be adapted to the investigation of intermediate coagulation structures of the spinning fiber. Results are discussed for nylon-6 and polyurethane wet-spun fibers

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Developmental patterns in human blood–brain barrier and blood–cerebrospinal fluid barrier ABC drug transporter expression

When drugs exert their effects in the brain, linear extrapolation of doses from adults could be harmful for children as the blood–brain barrier (BBB) and blood–CSF barrier (BCSFB) function is still immature. More specifically, age-related variation in membrane transporters may impact brain disposition. As human data on brain transporter expression is scarce, age dependent [gestational age (GA), postnatal age (PNA), and postmenstrual age (PMA)] variation in immunohistochemical localization and staining intensity of the ABC transporters P-glycoprotein (Pgp), breast cancer resistance protein (BCRP), and multidrug resistance-associated proteins 1, 2, 4, and 5 (MRP1/2/4/5) was investigated. Post mortem brain cortical and ventricular tissue was derived from 23 fetuses (GA range 12.9–39 weeks), 17 neonates (GA range 24.6–41.3 weeks, PNA range 0.004–3.5 weeks), 8 children (PNA range 0.1–3 years), and 4 adults who died from a wide variety of underlying conditions. In brain cortical BBB, immunostaining increased with age for Pgp and BCRP, while in contrast, MRP1 and MRP2 staining intensity appeared higher in fetuses, neonates, and children, as compared to adults. BCSFB was positively stained for Pgp, MRP1, and MRP2 and appeared stable across age, while BCRP was not detected. MRP4 and MRP5 were not det

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Intra-individual ECG changes over 25 years: How long can elective ECGs be used as reference for acute ischemia detection?

Cardiolog