Breakdown of diameter selectivity in a reductive hydrogenation reaction of single-walled carbon nanotubes

Reductive hydrogenation was applied to two types of single-walled carbon nanotubes with different diameter range. Alkali metal intercalation, followed by reaction with methanol, led to hydrogenated products. Both yield and selectivity of this reaction showed strong dependence on diameter, contrary to expectation based on simple curvature effects. The observed yield, as detected by thermogravimetry-mass spectrometry and 1H-NMR, is drastically reduced in small-diameter tubes where the alkali dopant does not reach the inside of the bundles. Wide range optical transmission measurements were employed to determine the selectivity and indicate that besides higher yield, lower diameter selectivity occurs above a critical diameter

Sensing Layer for Ni Detection in Water Created by Immobilization of Bioengineered Flagellar Nanotubes on Gold Surfaces

The environmental monitoring of Ni is targeted at a threshold limit value of 0.34 mu M, as set by the World Health Organization. This sensitivity target can usually only be met by time-consuming and expensive laboratory measurements. There is a need for inexpensive, field-applicable methods, even if they are only used for signaling the necessity of a more accurate laboratory investigation. In this work, bioengineered, protein-based sensing layers were developed for Ni detection in water. Two bacterial Ni-binding flagellin variants were fabricated using genetic engineering, and their applicability as Ni-sensitive biochip coatings was tested. Nanotubes of mutant flagellins were built by in vitro polymerization. A large surface density of the nanotubes on the sensor surface was achieved by covalent immobilization chemistry based on a dithiobis(succimidyl propionate) cross-linking method. The formation and density of the sensing layer was monitored and verified by spectroscopic ellipsometry and atomic force microscopy. Cyclic voltammetry (CV) measurements revealed a Ni sensitivity below 1 mu M. It was also shown that, even after two months of storage, the used sensors can be regenerated and reused by rinsing in a 10 mM solution of ethylenediaminetetraacetic acid at room temperature

Jelfeldolgozás a sejtben: a kalpain és protein kináz rendszerek és kölcsönhatásaik = Intracellular signal processing: the calpain and protein kinase/phosphatase systems, and their interactions

1. Bizonyítottuk, hogy a kalpain B aktív és inaktív formája foszforilálható PKA, ERK1 és ERK2 kinázokkal, azonosítottuk az in vitro foszforilációs helyeket, és meghatároztuk a foszforilált fehérje megváltozott enzimológiai paramétereit. 2. Előállítottuk az összes Drosophila kalpain elleni antitestet. 3. Kidolgoztunk egy háromdimenziós elektroforetikus eljáráson alapuló, in vivo szubsztrát azonosításra használható módszert, amelynek segítségével számos kalpain szubsztrátot azonosítottunk. 4. Kifejlesztettünk egy sejtpenetráns, szintetikus kalpain szubsztrátot, amely a jelenleg ismert szubsztrátok közül a legérzékenyebb. 5. Kifejlesztettünk egy sejtpenetráns, szintetikus kalpain-aktiváló peptid párt, amely a kalpainok sejten belüli, calcium-mentes és specifikus aktiválására képes. 6. Kimutattuk, hogy patkány hippokampális agyszeletekben a kalpainok specifikus aktiválása az alap-ingerlékenység és az LTP szignifikáns növekedését idézi elő. 7. Kalpain A, kalpain B és kalpain A/B mutáns Drosophila vonalakat állítottunk elő. Elemeztük a fehérjék expresszióját vad és mutáns vonalakban, továbbá vizsgáltuk a fenotípusra gyakorolt hatásukat. A kalpain B fehérjéről megállapítottuk, hogy fontos szerepet játszik a határsejtek vándorlásában. 8. Drosophila kalpain interferencia vonalakat állítottunk elő: a kalpain B csendesített vonalak egyedei csökkent fertilitásúak voltak, a kettős mutánsok szintetikus szemiletalitást mutattak. A kalpain C hiánya letalitást okozott. | 1. We provided evidence that both the active and inactive forms of calpain B can be phosphorylated by PKA, ERK1 and ERK2. Phosphorylation sites were localized and the enzymological parameters of the modified enzymes were determined. 2. Antibodies have been generated against all forms of Drosophila calpain. 3. A new three-dimensional electrophoresis method has been developed to identify calpain substrates in vivo. Several novel substrates have been identified. 4. A synthetic, cell-permeable synthetic calpain susbtrate has been developed. This compound is more sensitive to the enzyme than any other known calpain substrate. 5. A peptide pair capable of calpain activation have also been developed. These sythetic peptides can penetrate cells and activate the enzyme in a calcium-independent manner. 6. It has been shown that specific activation of calpain(s) leads to a significantly incerased basal excitability and long-term potentiation (LTP) in rat hippocampal slices. 7. Drosophila lines mutant in calpain A, calpain B and calpain A/B have been generated. The effect of changes in calpain expression on phenotype was tested and it was found that calpain B plays a major role in regulating the migration of border cells. 8. Interference strains of Drosophila have also been generated. We found that silencing calpain B causes reduced fertility whereas double mutation causes synthetic semilethality. Calpain C deficit was found to be lethal

A távközlés új szabályozási rezsimje Magyarországon az EGK 1992-es harmonizációs törekvései tükrében

INST: L_08