Der Feldbegriff in seiner Anwendung auf das Problem der Zellteilung

Summary The authors show that in certain isolated tissues (cornea of frog, mouse cancer) the mitotic processes continue during at least one hour. They are very strongly stimulated by heat and also by mitogenetic radiation. In the case of the cancer cells new mitoses are promoted in considerable number. A detailed analysis of both energy factors leads to the conclusion that they effect a disturbance of the unstable constellations (structures) of the elementary particles in the cell-body. Thus a certain degree of disorganisation of its plasma seems to stimulate cell-division. This statement is, in the opinion of the authors a proof that cell-division is controlled by a field, the trajectories of the elementary particles of the cell-body being a function of their coordinates relative to the cell-axes.

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Résumé Les auteurs démontrent que dans certains tissus survivants (la cornée des yeux de grenouille et le cancer de souris) les mitoses continuent leur processus d'évolution durant au moins une heure. Par l'application de chaleur aussi bien que par l'irradiation mitogénétique on peut accélérer beaucoup le rhythme des mitoses en cours d'évolution et provoquer (dans les cas de cancer seulement) l'apparition d'un nombre considérable de nouvelles mitoses. L'analyse de l'action de ces deux facteurs d'énergie aboutit à la conclusion qu'il ne peut s'agir que d'un dérangement des constellations instables des éléments du corps cellulaire. On peut en déduire qu'un certain degré de désorganisation du plasme est favorable aux divisions cellulaires. En poursuivant et en développant cette conception, les auteurs arrivent à la conception du champ cellulaire de division, définissant les trajectoires des particules élémentaires comme fonction de ses coordonnés relativement aux axes des cellules.

     

A trypsin and chymotrypsin inhibitor from seeds of Bauhenia purpurea

A trypsin and chymotrypsin inhibitor was partially purified from Bauhenia purpurea seeds and separated from a second inhibitor by Ecteola cellulose chromatography. The factor inhibited bovine trypsin and chymotrypsin as well as pronase trypsin and elastase. It formed a complex with trypsin and with chymotrypsin, but a ternary complex could not be detected. Differences were detected in the effect on trypsin and on chymotrypsin, although one enzyme interfered with the inhibition of the other. The results obtained point to two active centers on the inhibitor for the trypsin and chymotrypsin inhibition such that the one cannot complex with the inhibitor after this inhibitor had complexed with the other.     

Investigations on the genetics of foaming in wine yeasts

Summary The phenomenon of foaming is an undesirable characteristic of some wine yeasts. Investigation of this phenotype indicated that it is under the control of at least two dominant genes 21 centimorgans apart on the same chromosome. Elimination of the foaming character by hybridisation demonstrates that pure-culture wine yeast material can be improved by this technique.     

Differences in the response of sunflower (Helianthus annuus) subjected to flooding and drought stress

Wample, R. L. and Thornton, R. K. 1984. Differences in the response of sunflower ( Helianthus annuus ) subjected to flooding and drought stress.
Comparison of drought- and flood-stressed sunflower plants ( Helianthus annuus L. hybrid 894) showed some similarities in response but differences in the mechanisms responsible for the responses to stress. Drought–stressed plants showed typical reductions in leaf water potential with increasing stress accompanied by increased leaf resistance. Photosynthesis declined while photorespiration increased after 48 and 96 h of drought stress. A primary reason for reduced photosynthesis in drought-stressed plants was increased stomatal resistance. No significant 0change in leaf water potential or in leaf resistance in flooded plants was found in this study. However, photosynthesis declined in a manner similar to that in drought-stressed plants and photorespiration showed only a transient increase at 48 h. Dark respiration was significantly higher at 48 and 96 h but the magnitude of the increase cannot account for the reduction in photosynthesis. Since the photosynthetic rate of flooded plants declined while stomata remained open, an effect at a more fundamental level is suggested and is thought to be related to disruption of carbohydrate transport.     

What is Killing Organic Photovoltaics: Light‐Induced Crosslinking as a General Degradation Pathway of Organic Conjugated Molecules

In view of a rapid development and increase in efficiency of organic solar cells, reaching their long‐term operational stability represents now one of the main challenges to be addressed on the way toward commercialization of this photovoltaic technology. However, intrinsic degradation pathways occurring in organic solar cells under realistic operational conditions remain poorly understood. The light‐induced dimerization of the fullerene‐based acceptor materials discovered recently is considered to be one of the main causes for burn‐in degradation of organic solar cells. In this work, it is shown that not only the fullerene derivatives but also different types of conjugated polymers and small molecules undergo similar light‐induced crosslinking regardless of their chemical composition and structure. In the case of conjugated polymers, crosslinking of macromolecules leads to a rapid increase in their molecular weight and consequent loss of solubility, which can be revealed in a straightforward way by gel permeation chromatography analysis via a reduction/loss of signal and/or smaller retention times. Results of this work, thus, shift the paradigm of research in the field toward designing a new generation of organic absorbers with enhanced intrinsic photochemical stability in order to reach practically useful operation lifetimes required for successful commercialization of organic photovoltaics.     

Hybrid Perovskite‐Organic Flexible Tandem Solar Cell Enabling Highly Efficient Electrocatalysis Overall Water Splitting

Perovskite‐organic tandem solar cells are attracting more attention due to their potential for highly efficient and flexible photovoltaic device. In this work, efficient perovskite‐organic monolithic tandem solar cells integrating the wide bandgap perovskite (1.74 eV) and low bandgap organic active PBDB‐T:SN6IC‐4F (1.30 eV) layer, which serve as the top and bottom subcell, respectively, are developed. The resulting perovskite‐organic tandem solar cells with passivated wide‐bandgap perovskite show a remarkable power conversion efficiency (PCE) of 15.13%, with an open‐circuit voltage (V_oc) of 1.85 V, a short‐circuit photocurrent (J_sc) of 11.52 mA cm^?2, and a fill factor (FF) of 70.98%. Thanks to the advantages of low temperature fabrication processes and the flexibility properties of the device, a flexible tandem solar cell which obtain a PCE of 13.61%, with V_oc of 1.80 V, J_sc of 11.07 mA cm^?2, and FF of 68.31% is fabricated. Moreover, to demonstrate the achieved high V_oc in the tandem solar cells for potential applications, a photovoltaic (PV)‐driven electrolysis system combing the tandem solar cell and water splitting electrocatalysis is assembled. The integrated device demonstrates a solar‐to‐hydrogen efficiency of 12.30% and 11.21% for rigid, and flexible perovskite‐organic tandem solar cell based PV‐driven electrolysis systems, respectively.     

Associations between sensitivity to antibiotics,disinfectants and heavy metals in natural,clinical and laboratory isolates of Escherichia coli

Bacteria in nature often encounter non-antibiotic antibacterials (NAAs), such as disinfectants and heavy metals, and they can evolve resistance via mechanisms that are also involved in antibiotic resistance. Understanding whether susceptibility to different types of antibacterials is non-randomly associated across natural and clinical bacteria is therefore important for predicting the spread of resistance, yet there is no consensus about the extent of such associations or underlying mechanisms. We tested for associations between susceptibility phenotypes of 93 natural and clinical Escherichia coli isolates to various NAAs and antibiotics. Across all compound combinations, we detected a small number of non-random associations, including a trio of positive associations among chloramphenicol, triclosan and benzalkonium chloride. We investigated genetic mechanisms that can explain such associations using genomic information, genetic knockouts and experimental evolution. This revealed some mutations that are selected for by experimental exposure to one compound and confer cross-resistance to other compounds. Surprisingly, these interactions were asymmetric: selection for chloramphenicol resistance conferred cross-resistance to triclosan and benzalkonium chloride, but selection for triclosan resistance did not confer cross-resistance to other compounds. These results identify genetic changes involved in variable cross-resistance across antibiotics and NAAs, potentially contributing to associations in natural and clinical bacteria.     

Exploring movement patterns and changing distributions of baleen whales in the western North Atlantic using a decade of passive acoustic data

Six baleen whale species are found in the temperate western North Atlantic Ocean, with limited information existing on the distribution and movement patterns for most. There is mounting evidence of distributional shifts in many species, including marine mammals, likely because of climate‐driven changes in ocean temperature and circulation. Previous acoustic studies examined the occurrence of minke (Balaenoptera acutorostrata) and North Atlantic right whales (NARW; Eubalaena glacialis). This study assesses the acoustic presence of humpback (Megaptera novaeangliae), sei (B. borealis), fin (B. physalus), and blue whales (B. musculus) over a decade, based on daily detections of their vocalizations. Data collected from 2004 to 2014 on 281 bottom‐mounted recorders, totaling 35,033 days, were processed using automated detection software and screened for each species' presence. A published study on NARW acoustics revealed significant changes in occurrence patterns between the periods of 2004–2010 and 2011–2014; therefore, these same time periods were examined here. All four species were present from the Southeast United States to Greenland; humpback whales were also present in the Caribbean. All species occurred throughout all regions in the winter, suggesting that baleen whales are widely distributed during these months. Each of the species showed significant changes in acoustic occurrence after 2010. Similar to NARWs, sei whales had higher acoustic occurrence in mid‐Atlantic regions after 2010. Fin, blue, and sei whales were more frequently detected in the northern latitudes of the study area after 2010. Despite this general northward shift, all four species were detected less on the Scotian Shelf area after 2010, matching documented shifts in prey availability in this region. A decade of acoustic observations have shown important distributional changes over the range of baleen whales, mirroring known climatic shifts and identifying new habitats that will require further protection from anthropogenic threats like fixed fishing gear, shipping, and noise pollution.