Zur „Genauigkeit”︁ bei J. G. Mendel

When taking into account J. G. MENDEL's observed frequencies and comparing them with those noted down by BATESON, CORRENS and DARBISHIRE no ?striking”? preciseness in accordance with the statement made by F. WELLING is to be noticed statistically. By means of the four-field table measure K speculations as to a ?too precise”? indication of frequencies are to be refuted in an easy way.     

38. F. Passecker: Adulter Hopfen mit „Jugendform belaubung”

Bisher waren nur bei Nadelgehölzen adulte Individuen und Klone mit ausschließlich jugendformartiger Belaubung (Benadelung) bekannt, die früher (seit Beissner ) als ?fixierte Jugendformen” galten (z.B. Chamaecyparis pisifera squarrosa). In der vorliegenden Arbeit wird gezeigt, daß jugendformartige Belaubung auch beim adulten Hopfen (Humulus lupulus) vorkommt. Solche Pflanzen, seien es Nadel-, Laubgehölze oder krautige Pflanzen, werden auf Grund von Versuchsergebnissen heute nicht mehr als ?fixierte Jugendformen” im Sinne Beissners , sondern als Varietäten aufgefaßt, die aus genetischen Gründen auch in der adulten Phase eine jugendformartige Belaubung tragen und dadurch von der typischen Art abweichen.     

Synthesis of photodeprotectable serine derivatives. “Caged serine”

The synthesis of O-(4,5-dimethoxy-2-nitrobenzyl)serine has been accomplished by treatment of an FMOC-aziridinecarboxylate with nitroveratryl alcohol followed by hydrolysis. Irradiation with a Pyrex-filtered 450W Hanovia lamp releases serine with a half-life of 4.4 min. o-Nitrobenzyl serinate is prepared by direct esterification. Vycor-filtered irradiation releases serine with a half-life of 6.9 min.     

“Inflammatory” Cytokines

If cytokines are constitutively expressed by and act on neurons in normal adult brain, then we may have to modify our current view that they are predominantly inflammatory mediators. We critically reviewed the literature to determine whether we could find experimental basis for such a modification. We focused on two "proinflammatory" cytokines, interleukin (IL)-1 and tumor necrosis factor-alpha (TNFalpha) because they have been most thoroughly investigated in shaping our current thinking. Evidence, although equivocal, indicates that the genes coding for these cytokines and their accessory proteins are expressed by neurons, in addition to glial cells, in normal brain. Their expression is region- and cell type-specific. Furthermore, bioactive cytokines have been extracted from various regions of normal brain. The cytokines' receptors selectively are present on all neural cell types, rendering them responsive to cytokine signaling. Blocking their action modifies multiple neural "housekeeping" functions. For example, blocking IL-1 or TNFalpha by several independent means alters regulation of sleep. This indicates that these cytokines likely modulate in the brain behavior of a normal organism. In addition, these cytokines are likely involved in synaptic plasticity, neural transmission, and Ca2+ signaling. Thus, the evidence strongly suggests that these cytokines perform neural functions in normal brain. We therefore propose that they should be thought of as neuromodulators in addition to inflammatory mediators.     

Heterogeneous Single Atom Electrocatalysis,Where “Singles” Are “Married”

There is an intensive search for heterogeneous single atom catalysts (SACs) of high activity, efficiency, durability, and selectivity for a wide variety of electrocatalytic conversion and chemical reactions, such as the hydrogen evolution reaction (HER), oxygen evolution/reduction reaction (OER and ORR), CO₂ reduction reaction (CO₂ RR), and nitrogen reduction reaction (NRR). With the downsizing from nanoparticles and clusters to single atoms, there are steady changes in the bond and coordination environment for each and every atom involved. Indeed, the single atoms in these electrocatalysts are not “singles”; they are “married” to the supporting surfaces, and their performance is controlled by the bonding and coordination with the substrate surfaces. Herein, an overview is presented on the brief history leading to the rapid development of SACs and their current status, by focusing on their synthesis, control of composition, strategies to realize single atoms with the desired bonds and coordination, and targeted performance in selected reactions. Their applications in the selected spectrum of energy conversion and chemical reactions are discussed, in relation to their structures at varying length scales down to the atomic level. A particular emphasis is placed on on‐going research activities, together with the future perspectives and particular challenges for SACs.