Characterizing the geometry of InAs nanowires using mirror electron microscopy.

Mirror electron microscopy (MEM) imaging of InAs nanowires is a non-destructive electron microscopy technique where the electrons are reflected via an applied electric field before they reach the specimen surface. However strong caustic features are observed that can be non-intuitive and difficult to relate to nanowire geometry and composition. Utilizing caustic imaging theory we can understand and interpret MEM image contrast, relating caustic image features to the properties and parameters of the nanowire. This is applied to obtain quantitative information, including the nanowire width via a through-focus series of MEM images.

Polyvinylchloride infusion lines expose infants to large amounts of toxic plasticizers.

PURPOSE: The purpose of this study was to evaluate whether infusion lines are able to leach plasticizers in substantial amounts and thus be a candidate substance for hepatotoxic effects during long-term total parenteral nutrition (TPN). METHODS: TPN solutions, blood products, and selected drugs typical for preterm infants concerning amount, content, and infusion time were perfused through common polyvinylchloride (PVC) infusion lines. Concentration of diethylhexyl-phthalate (DEHP) before and after perfusion was determined by gas chromatography/mass spectrometry. RESULTS: Daily quantities of DEHP by 24-hour infusions were Lipid emulsion 20%: 10185.6 microg; aminoacid/glucose-solution: 116.2 microg; midazolaminfusion for sedation: 26.4 microg; fentanyl for sedation: 132.5 microg; propofol for sedation: 6561.0 microg. The amount of DEHP by single doses of blood products (20 mL) were packed red blood cells: 144-608 microg; platelet rich plasma: 928 microg; and fresh frozen plasma: 552-8108 microg. The dose of DEHP for a typical preterm neonate requiring TPN and additional therapy like sedation or blood products is at minimum 10 mg and can easily reach 20 mg/d. CONCLUSION: This large amount of DEHP is especially disturbing, because it effects the most vulnerable patients (neonates). Whether there is a relation to TPN-induced hepatobiliary dysfunction remains to be elucidated and is under investigation. With respect to recent literature, a biological effect of these doses must be assumed.

The five cleavage-stage (CS) histones of the sea urchin are encoded by a maternally expressed family of replacement histone genes: functional equivalence of the CS H1 and frog H1M (B4) proteins.

The cleavage-stage (CS) histones of the sea urchin are known to be maternally expressed in the egg, have been implicated in chromatin remodeling of the male pronucleus following fertilization, and are the only histone variants present in embryonic chromatin up to the four-cell stage. With the help of partial peptide sequence information, we have isolated and identified CS H1, H2A, H2B, H3, and H4 cDNAs from egg poly(A)+ mRNA of the sea urchin Psammechinus miliaris. All five CS proteins correspond to replacement histone variants which are encoded by replication-independent genes containing introns, poly(A) addition signals, and long nontranslated sequences. Transcripts of the CS histone genes could be detected only during oogenesis and in development up to the early blastula stage. The CS proteins, with the exception of H4, are unique histones which are distantly related in sequence to the early, late, and sperm histone subtypes of the sea urchin. In contrast, the CS H1 protein displays highest sequence homology with the H1M (B4) histone of Xenopus laevis. Both H1 proteins are replacement histone variants with very similar developmental expression profiles in their respective species, thus indicating that the frog H1M (B4) gene is a vertebrate homolog of the CS H1 gene. These data furthermore suggest that the CS histones are of ancient evolutionary origin and may perform similar conserved functions during oogenesis and early development in different species.