Heat transport in an open transverse-field Ising chain

The heat conduction in an open transverse-field Ising chain is studied by using quantization in the Fock space of operators in the weak coupling regimes, i.e. the coupling is much smaller than the transverse field. The non-equilibrium steady state is obtained for large size systems coupled to Markovian baths at its ends. The ballistic transport is observed in the uniform chain and normal diffusion in the random-exchange chain. {In addition, the ballistic-diffusive transition is found at the intermediate disorder regime.} The thermal conductivity $\kappa$ is also calculated in the low and high temperature regimes. It is shown that $\kappa$ decays as $\kappa\sim T^{-2}$ at high temperatures.Comment: 6 pages, 7 figure

Markovian Master Equations: A Critical Study

We derive Markovian master equations of single and interacting harmonic systems in different scenarios, including strong internal coupling. By comparing the dynamics resulting from the corresponding Markovian master equations with exact numerical simulations of the evolution of the global system, we precisely delimit their validity regimes and assess the robustness of the assumptions usually made in the process of deriving the reduced dynamics. The proposed method is sufficiently general to suggest that the conclusions made here are widely applicable to a large class of settings involving interacting chains subject to a weak interaction with an environment.Comment: 40 pages, 14 figures, final versio

Radiation chemistry of solid-state carbohydrates using EMR

We review our research of the past decade towards identification of radiation-induced radicals in solid state sugars and sugar phosphates. Detailed models of the radical structures are obtained by combining EPR and ENDOR experiments with DFT calculations of g and proton HF tensors, with agreement in their anisotropy serving as most important criterion. Symmetry-related and Schonland ambiguities, which may hamper such identification, are reviewed. Thermally induced transformations of initial radiation damage into more stable radicals can also be monitored in the EPR (and ENDOR) experiments and in principle provide information on stable radical formation mechanisms. Thermal annealing experi-ments reveal, however, that radical recombination and/or diamagnetic radiation damage is also quite important. Analysis strategies are illustrated with research on sucrose. Results on dipotassium glucose-1-phosphate and trehalose dihydrate, fructose and sorbose are also briefly discussed. Our study demonstrates that radiation damage is strongly regio-selective and that certain general principles govern the stable radical formation

The Substantial Role of Cell and Nanoparticle Surface Properties in the Antibacterial Potential of Spherical Silver Nanoparticles

Marta Krychowiak-Maśnicka,1,* Weronika Paulina Wojciechowska,1,* Karolina Bogaj,1 Aleksandra Bielicka-Giełdoń,2 Ewa Czechowska,3 Magdalena Ziąbka,4 Magdalena Narajczyk,5 Anna Kawiak,6 Tomasz Mazur,7 Beata Szafranek,2 Aleksandra Królicka1 1University of Gdansk, Intercollegiate Faculty of Biotechnology, Laboratory of Biologically Active Compounds, Gdansk, Poland; 2University of Gdansk, Faculty of Chemistry, Gdansk, Poland; 3University of Gdansk, Intercollegiate Faculty of Biotechnology, Laboratory of Experimental and Translational Immunology, Gdansk, Poland; 4AGH University of Krakow, Faculty of Materials Science and Ceramics, Department of Ceramics and Refractories, Krakow, Poland; 5University of Gdansk, Faculty of Biology, Bioimaging Laboratory, Gdansk, Poland; 6University of Gdansk, Intercollegiate Faculty of Biotechnology, Laboratory of Plant Protection and Biotechnology, Gdansk, Poland; 7AGH University of Krakow, Academic Centre for Materials and Nanotechnology, Krakow, Poland*These authors contributed equally to this workCorrespondence: Marta Krychowiak-Maśnicka, Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of the University of Gdansk and the Medical University of Gdansk, University of Gdansk, Abrahama 58, Gdansk, 80-307, Poland, Email [email protected]: Although it is well known that the size, shape, and surface chemistry affect the biological potential of silver nanoparticles (AgNPs), the published studies that have considered the influence of AgNP surface on antibacterial activity have not provided conclusive results. This is the first study whose objective was to determine the significance of the surface net charge of AgNPs on their antibacterial potential, attraction to bacterial cells, and cell envelope disruption, considering differences in bacterial surface properties.Methods: We evaluated five commercial AgNP colloids with identical size and shape but different surface ligands. We thoroughly characterized their physicochemical properties, including the zeta potential, hydrodynamic diameter, and polydispersity index, and determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), along with silver absorption into bacterial cells. Moreover, we investigated structural changes in bacteria treated with AgNPs by using a crystal violet assay and electron microscopy.Results: The zeta potential of AgNPs ranged from − 47.6 to +68.5 mV, with a hydrodynamic diameter of 29– 87 nm and a polydispersity index of 0.349– 0.863. Bacterial susceptibility varied significantly (0.5 ≤ MIC ≤ 256 μg Ag/mL; 1 ≤ MBC ≤ 256 μg Ag/mL); we found the lowest susceptibility in bacteria with a cell wall or a polysaccharide capsule. The most active AgNPs (0.5 ≤ MIC ≤ 32 μg Ag/mL; 2 ≤ MBC ≤ 64 μg Ag/mL) had a moderate surface charge (− 21.5 and +14.9 mV). The antibacterial potential was unrelated to ion dissolution or cell envelope disruption, and bacterial cells absorbed less of the most active AgNPs (1.75– 7.65%).Conclusion: Contrary to previous reports, we found that a moderate surface charge is crucial for the antibacterial activity of AgNPs, and that a significant attraction of the nanoparticle to the cell surface reduces the antibacterial potential of AgNPs. These findings challenge the existing views on AgNP antibacterial mechanisms and interactions with bacterial cells. Keywords: human pathogen, ESKAPE, Klebsiella pneumoniae, cell envelope, ICP-OES, cell–nanoparticle interactio

The Substantial Role of Cell and Nanoparticle Surface Properties in the Antibacterial Potential of Spherical Silver Nanoparticles [Response to Letter]

Marta Krychowiak-Maśnicka,1,* Weronika Paulina Wojciechowska,1,* Karolina Bogaj,1 Aleksandra Bielicka-Giełdoń,2 Ewa Czechowska,3 Magdalena Ziąbka,4 Magdalena Narajczyk,5 Anna Kawiak,6 Tomasz Mazur,7 Beata Szafranek,2 Aleksandra Królicka1 1University of Gdansk, Intercollegiate Faculty of Biotechnology, Laboratory of Biologically Active Compounds, Gdansk, Poland; 2University of Gdansk, Faculty of Chemistry, Gdansk, Poland; 3University of Gdansk, Intercollegiate Faculty of Biotechnology, Laboratory of Experimental and Translational Immunology, Gdansk, Poland; 4AGH University of Krakow, Faculty of Materials Science and Ceramics, Department of Ceramics and Refractories, Krakow, Poland; 5University of Gdansk, Faculty of Biology, Bioimaging Laboratory, Gdansk, Poland; 6University of Gdansk, Intercollegiate Faculty of Biotechnology, Laboratory of Plant Protection and Biotechnology, Gdansk, Poland; 7AGH University of Krakow, Academic Centre for Materials and Nanotechnology, Krakow, Poland*These authors contributed equally to this workCorrespondence: Marta Krychowiak-Maśnicka, Laboratory of Biologically Active Compounds, Intercollegiate Faculty of Biotechnology of the University of Gdansk and the Medical University of Gdansk, University of Gdansk, Abrahama 58, Gdansk, 80-307, Poland, Email [email protected]

DNA damage and repair in endometrial cancer in correlation with the hOGG1 and RAD51 genes polymorphism

The cellular reaction to the DNA-damaging agents may modulate individual’s cancer susceptibility. This reaction is mainly determined by the efficacy of DNA repair, which in turn, may be influenced by the variability of DNA repair genes, expressed by their polymorphism. The hOGG1 gene encodes a glycosylase of base excision repair and RAD51 specifies a key protein in homologues recombination repair. Both proteins can be involved in the repair of DNA lesions, which are known to contribute to endometrial cancer. In the present work we determined the extent of basal DNA damage and the efficacy of removal of DNA damage induced by hydrogen peroxide and N-methyl-N′-nitro N-nitrosoguanidyne (MNNG) in peripheral blood lymphocytes of 30 endometrial cancer patients and 30 individuals without cancer. The results from DNA damage and repair study were correlated with the genotypes of two common polymorphisms of the hOGG1 and RAD51 genes: a G>C transversion at 1245 position of the hOGG1 gene producing a Ser → Cys substitution at the codon 326 (the Ser326Cys polymorphism) and a G>C substitution at 135 position of the RAD51 gene (the 135G>C polymorphism). DNA damage and repair were evaluated by alkaline single cell gel electrophoresis and genotypes were determined by restriction fragment length polymorphism PCR. We observed a strong association between endometrial cancer and the C/C genotype of the 135G>C polymorphism of the RAD51 gene. Moreover, there was a strong correlation between that genotype and endometrial cancer occurrence in subjects with a high level of basal DNA damage. We did not observe any correlation between the Ser326Cys polymorphism of the hOGG1 gene and endometrial cancer. Our result suggest that the 135G>C polymorphism of the RAD51 gene may be linked to endometrial cancer and can be considered as an additional marker of this disease

Definition, diagnosis and treatment of oligometastatic oesophagogastric cancer: A Delphi consensus study in Europe

Background: Local treatment improves the outcomes for oligometastatic disease (OMD, i.e. an intermediate state between locoregional and widespread disseminated disease). However, consensus about the definition, diagnosis and treatment of oligometastatic oesophagogastric cancer is lacking. The aim of this study was to develop a multidisciplinary European consensus statement on the definition, diagnosis and treatment of oligometastatic oesophagogastric cancer. Methods: In total, 65 specialists in the multidisciplinary treatment for oesophagogastric cancer from 49 expert centres across 16 European countries were requested to participate in this Delphi study. The consensus finding process consisted of a starting meeting, 2 online Delphi questionnaire rounds and an online consensus meeting. Input for Delphi questionnaires consisted of (1) a systematic review on definitions of oligometastatic oesophagogastric cancer and (2) a discussion of real-life clinical cases by multidisciplinary teams. Experts were asked to score each statement on a 5-point Likert scale. The agreement was scored to be either absent/poor (<50%), fair (50%–75%) or consensus (≥75%). Results: A total of 48 experts participated in the starting meeting, both Delphi rounds, and the consensus meeting (overall response rate: 71%). OMD was considered in patients with metastatic oesophagogastric cancer limited to 1 organ with ≤3 metastases or 1 extra-regional lymph node station (consensus). In addition, OMD was considered in patients without progression at restaging after systemic therapy (consensus). For patients with synchronous or metachronous OMD with a disease-free interval ≤2 years, systemic therapy followed by restaging to consider local treatment was considered as treatment (consensus). For metachronous OMD with a disease-free interval >2 years, either upfront local treatment or systemic treatment followed by restaging was considered as treatment (fair agreement). Conclusion: The OMEC project has resulted in a multidisciplinary European consensus statement for the definition, diagnosis and treatment of oligometastatic oesophagogastric adenocarcinoma and squamous cell cancer. This can be used to standardise inclusion criteria for future clinical trials

Seasonal changes in the numbers of aerobic and anaerobic cellulolytic bacteria in water, soil and on plants of mid-forest wetlands near Olsztyn

Badano zmienność sezonową liczebności bakterii celulolitycznych w wodzie, glebie i na powierzchni zanurzonych w wodzie oraz na wynurzonych częściach turzycy błotnej (Carex acutiformis Ehrb.), a także na jej korzeniach (obumarłych i żywych), w dwóch kolejnych cyklach rocznych (w latach 1993 i 1994). W wodzie liczba bakterii rozkładających celulozę w warunkach tlenowych nie przekraczała 1,4· 10³cm-³ (NPL). Więcej bakterii celulolitycznych występowało na powierzchni zanurzonych w wodzie fragmentów turzycy błotnej, w glebie okalającej system korzeniowy tej rośliny oraz ryzosferze korzeni ubiegłorocznych i tegorocznych (żywych). W cyklu rocznym z reguły więcej ich występowało latem, wyjątkowo w innym okresie. Różnice w liczebności bakterii celulolitycznych w odpowiednich środowiskach z poszczególnych stanowisk były najczęściej niewielkie. Bakterie rozkładające celulozę w warunkach beztlenowych (Clostridium sp.) we wszystkich biotopach występowały w mniejszych ilościach. Często brak ich było w badanej objętości wody lub w badanej masie gleby i poszczególnych części rośliny.The distribution and seasonal changes in the number of cellulose-egrading bacteria in the water, soil and on the surface of aerial leaves and immersed parts of the sedge (Carex acutiformis Ehrb.) and on dead and live roots in two consecutive year cycle in 1993 and 1994 were examined. In the water of the examined wetland the number of cellulose-degrading bacteria under aerobic conditions did not exceed 1.4· 10³ cm-³. More bacteria were found on immersed parts of the sedge, in the soil surrounding its root system and on dead and live roots surface. Bacteria were most numerous in the summer and only exceptionally occurred in other periods. The differences in their numbers from respective habitats in particular sampling sites were often small. Under anaerobic conditions the cellulose-degrading bacteria (Clostridium sp.) were less frequent in all habitats. They often were absent from the examined water volume or soil mass and on particular plant parts

Seasonal changes in the number of lecithin-mineralizing and tribasic calcium phosphate-solubilizing bacteria in water, soil and on plant surface of mid-forest wetlands near Olsztyn

Badano sezonowe zmiany liczebności bakterii mineralizujących lecytynę i rozpuszczających fosforan trójwapniowy w wodzie, glebie ryzosferowej turzycy błotnej (Carex acutiformis Ehrh.), na powierzchni zanurzonych w wodzie i wynurzonych częściach tej rośliny oraz jej korzeniach (obumarłych i żywych). Badania przeprowadzono w dwóch kolejnych cyklach rocznych (w latach 1993 i 1994). Stwierdzono małą liczebność badanych grup drobnoustrojów w wodzie, większą na zanurzonych w niej częściach rośliny, największą w glebie ryzosferowej i poza ryzosferą. W cyklu rocznym większa liczba drobnoustrojów występowała w miesiącach letnich, wyjątkowo jesienią. Obie badane grupy drobnoustrojów stanowiły znikomy procent ogólnej liczby bakterii heterotroficznych, oznaczanych na podłożu z tryptonem, glukozą i ekstraktem drożdżowym. Stosunek liczbowy bakterii mineralizujących lecytynę na korzeniach turzycy błotnej i bakterii występujących w glebie ryzosferowej wynosił od 0,05 do 4,5, a bakterii rozpuszczających fosforan trójwapniowy w obu tych ekosystemach od 0,2 do 4,4.Seasonal changes in the numbers of lecithin-mineralizing and tricalcium phosphate-dissolving bacteria in water, soil, on the sedge (Carex acutiformis Ehrh.) surfaces immersed in water, on its leaves and roots (dead and alive) were studied. The study was carried out in two annual cycles (in 1993 and 1994). Low numbers of studied groups of microorganisms were found in water, higher on the surface of submerged parts of plants and the highest in the soil in and outside the rhizosphere. In the annual cycle, bacteria were most numerous in summer and present only exceptionally in the autumn months. Both studied groups of bacteria constituted negligible part of the total number of heterotrophic bacteria. The ratio of lecithin-mineralizing bacteria in the rhizosphere to those oustside the plant rhizosphere ranged from 0.05 to 4.5. Respective proportion of tribasic calcium phosphatesolubilizing bacteria in both sites ranged from 0.2 to 4.4