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The aim of the study was to evaluate the effect of two types of negatively charged quasi-spherical silver nanoparticles (AgNPs) at concentrations of 10, 20 and 30 mg L−1 and silver ions at a concentration of 30 mg L−1 on the growth, selected physiological aspects and yielding of wheat (Triticum aestivum L.) cv. Tybalt, and on plant resistance to seedling blight. Seed germination, α-amylase activity in seeds, morphology and infestation of seedlings by pathogens were assessed in a hydroponic treatment. Growth rate, PSII efficiency, heading and yield of the same plants were then analysed in pot culture. Results showed that the AgNPs and silver ions had a negative effect on roots, but reduced seedling blight and improved leaf area compared to the control. In addition, the AgNPs reduced with sodium borohydride in the presence of trisodium citrate at concentrations of 10 and 20 mg L−1 stimulated germination, α-amylase activity and shoot length, which was not observed in the case of silver ions and the AgNPs reduced with sodium hypophosphite in the presence of sodium hexametaphosphate. In a pot experiment, the AgNPs improved plant growth, PSII efficiency, accelerated heading and increased yield-related parameters compared with the control. Results revealed the interaction strength in the following order: TCSB-AgNPs > SHSH-AgNPs > silver ions. TCSB-AgNPs in the lowest concentration had the most favourable effect, indicating their great potential for use in improving wheat cultivation.

The aim of the research was to evaluate the effect of three types of silver nanoparticles (AgNPs) with different physicochemical properties and silver ions delivered in the form of silver nitrate (AgNO3) at the concentration of 50 mg L−1 on germination and initial growth of monocots (common wheat, sorghum) and dicots (garden cress, white mustard). The AgNPs were prepared using trisodium citrate (TCSB-AgNPs), tannic acid (TA-AgNPs), and cysteamine hydrochloride (CHSB-AgNPs). They exhibited comparable shape, size distribution, and an average size equal to 15 ± 3 nm which was confirmed with the use of transmission electron microscopy. The electrokinetic characteristics revealed that CHSB-AgNPs have positive, whereas TCSB-AgNPs and TA-AgNPs negative surface charge. First, toxicity of the silver compounds was assessed using the Phytotestkit test. Next, after transferring seedlings to pots, shoot length, leaf surface, shoot dry mass, electrolyte leakage measurement, and photosystem II (PSII) efficiency were determined. AgNPs and silver ions delivered in the form of AgNO3 reduced root and shoots length of common wheat, sorghum, and garden cress; leaves surface of garden cress and white mustard; and shoots dry mass of white mustard. The positively charged CHSB-AgNPs and silver ions delivered in the form of AgNO3 showed the greatest inhibition effect. Moreover, silver ions and positively charged CHSB-AgNPs were more toxic to PSII of model plants than negatively charged TCSB-AgNPs and TA-AgNPs. AgNPs impact differed in the case of monocots and dicots, but the size of the changes was not significant, so it concerned individual parameters. The results revealed the interaction strength, which was generally similar in all tested plants, i.e., increasing negative effect in sequence TCSB-AgNPs 3

In this work, we have assessed the exposure of soil bacteria from potato monoculture to three types of silver nanoparticles (AgNPs) as well as silver ions (Ag+ ions) delivered in the form of silver nitrate and a commercially available fungicide. The diversity of the soil microbial community, enzymatic activity, and carbon source utilization were evaluated. It was found that only the fungicide significantly limited the abundance and activity of soil bacteria. Silver ions significantly reduced bacterial metabolic activity. In turn, one type of AgNPs prepared with the use of tannic acid (TA) increased bacterial load and activity. There was found in all AgNPs treated soils (1) a greater proportion of all types of persistent bacteria, i.e., Bacillus, Paenibacillus, and Clostridium; (2) a visible decrease in the proportion of Nocardioides, Arthrobacter, and Candidatus Solibacter; (3) almost complete depletion of Pseudomonas; (4) increase in the number of low-frequency taxa and decrease in dominant taxa compared to the control soil. Despite the general trend of qualitative changes in the bacterial community, it was found that the differences in the chemical structure of the AgNP stabilizing layers had a significant impact on the specific metabolic activity resulting from qualitative changes in the microbiome.

Background Although COVID-19 is associated with a mild course in children, a certain proportion requires admission to hospital due to SARS-CoV-2 infection and coexisting diseases. The prospective multicenter study aimed to analyze clinical factors influencing the length of the hospital stay (LoHS) in children with COVID-19. Methods The study included 1283 children from 14 paediatric infectious diseases departments with diagnosed SARS-CoV-2 infection. Children were assessed in respective centres regarding indications for admission to hospital and clinical condition. History data, clinical findings, laboratory parameters, treatment, and outcome, were collected in the paediatric SARSTer register. The group of children with a hospital stays longer than seven days was compared to the remaining patients. Parameters with a statistically significant difference were included in further logistic regression analysis. Results One thousand one hundred and ten children were admitted to the hospital, 763 children were hospitalized >24 h and 173 children >7 days. 268 children had comorbidities. Two hundred and eleven children had an additional diagnosis with coinfections present in 135 children (11%). Factors increasing the risk of higher LoHS included pneumonia [odds ratio—OR 3.028; 95% confidence interval—CI (1.878–4.884)], gastrointestinal symptoms [OR = 1.556; 95%CI (1.049–2.322)], or rash [OR = 2.318; 95%CI (1.216–4.418)] in initial clinical findings. Comorbidities [OR = 2.433; 95%CI (1.662–3.563)], an additional diagnosis [OR = 2.594; 95%CI (1.679–4.007)] and the necessity of the empirical antibiotic treatment [OR = 2.834; 95%CI (2.834–6.713)] were further factors related to higher LoHS. Conclusions The clinical course of COVID-19 was mild to moderate in most children. Factors increasing the risk of higher LoHS included pneumonia, gastrointestinal symptoms, comorbidities, an additional diagnosis, and the empirical antibiotic treatment.

The aim of this study was to assess the changes in chemical and microbial properties and enzymatic activity of soil enriched with vermicompost derived from household waste. The vermicompost was tested in the rhizosphere of Larix decidua seedlings cultivated in 10-L pots in: (i) nursery soil (as the control), (ii) soil with 10% v/v vermicompost, and (iii) with 20% v/v vermicompost. The impact of vermicompost was assessed in terms of soil C/N ratio; bacterial, fungal, and nematode counts; and enzymatic activity. It was found that vermicompost increased the C/N ratio from 21 to 32, as well as the content of nitrate from 78 to 134 mg kg−1, of ammonium from 14 to 139 mg kg−1, of phosphorus from 92 to 521 mg kg−1, and of potassium from 142 to 1912 mg kg−1, compared with the control soil. The abundance of beneficial bacteria was increased (from 8.61 × 107 to 37.9 × 107), along with decreases in microbiological ratios of fungi and bacteria (e.g. fungi/Bacillus from 0.18818 to 0.00425). A significant 2- to 4-fold increase was observed compared with the control in the number of beneficial nematodes belonging to bacterivorous, fungivorous, and predatory groups with no change in the abundance of plant-parasitic nematodes. Addition of vermicompost brought about a change in soil enzyme activity. Vermicompost reduced the activity of alkaline phosphatase only. Both doses of vermicompost led to an increase in the activity of acid phosphatase, inorganic pyrophosphatase, dehydrogenases, β-glucosidase, and urease. Only the higher dose had an effect on increasing the activity of o-diphenol oxidase and proteases. No significant change was observed for nitrate reductase. Also, the presence of antibiotics produced by bacteria was detected depending on the dose of vermicompost, e.g. iturin (ituC) and bacillomycin (bmyB) were found in soil with a dose of 20% v/v vermicompost. Overall, vermicompost produced from household waste can be an excellent organic fertilizer for larch forest nurseries.

This prospective multicenter cohort study aimed to analyze the epidemiological and clinical characteristics of coronavirus disease 2019 (COVID-19) in children. The study, based on the pediatric part of the Polish SARSTer register, included 1283 children (0 to 18 years) who were diagnosed with COVID-19 between 1 March 2020 and 31 December 2020. Household contact was reported in 56% of cases, more frequently in younger children. Fever was the most common symptom (46%). The youngest children (0–5 years) more frequently presented with fever, rhinitis and diarrhea. Teenagers more often complained of headache, sore throat, anosmia/ageusia and weakness. One fifth of patients were reported to be asymptomatic. Pneumonia was diagnosed in 12% of patients, more frequently in younger children. During the second wave patients were younger than during the first wave (median age 53 vs. 102 months, p &lt, 0.0001) and required longer hospitalization (p &lt, 0.0001). Significantly fewer asymptomatic patients were noted and pneumonia as well as gastrointestinal symptoms were more common. The epidemiological characteristics of pediatric patients and the clinical presentation of COVID-19 are age-related. Younger children were more frequently infected by close relatives, more often suffered from pneumonia and gastrointestinal symptoms and required hospitalization. Clinical courses differed significantly during the first two waves of the pandemic.

This study aimed to examine the hypothesis that silver nanoparticles (AgNPs) and silver ions might induce specific changes and thereby affect plant development and final yield. The experiment was performed on spring wheat, cultured hydroponically with two types of negatively charged AgNPs of an average size of 13–15 nm and silver ions for 14 days and then transplanted to pots with soil. Our results indicated that treatment with the AgNPs stabilized by specific compounds resulted in growth promotion and a reduced number of days to flowering, while that with the ionic form of Ag only caused greater growth in height without influencing the time to heading. Accelerated flowering was caused by changes in phytohormone balance, with GA6 found to be especially favorable. Nanoparticles and silver ions affected the function of photosystem II and the transport and partitioning of assimilates. Increases in the transport form of sugars such as sucrose, raffinose and sorbitol were associated with a considerable improvement in wheat yield, especially in the case of plants treated with the nanoparticle forms, which were more stable and resistant to oxidative dissolution.

The applications and benefits of nanotechnology in the agricultural and food sector are now established as a matter of fact, but scientists still have a problem to properly acknowledge the influence of nanocompounds on the environment. We are starting to use nanopesticides and nanofertilizers, but the effects they have on organisms in the environment can be diverse in nature – ranging from the beneficial to the harmful. Environmental microbiome can be strongly modified by nanoparticles. Soil microbiomes are the basis for healthy plants and crops. At the same time, the unique properties of nanomaterials make them particularly suitable for environmental remediation due to their high surface area-to-volume ratio, which often results in higher reactivity. Nanomaterials are starting to be used for the remediation of problematic contaminants (organic and organophosphorus compounds, volatile organic compounds, some heavy metals, or herbicides), and such use offers some very promising prospects. This chapter provides an overview of nanotechnology in general, including a description of the main categories of nanomaterials, the utilization of nanotechnology in the agricultural and food sector, as well as the use of nanomaterials in environmental remediation. Lastly, some toxicological aspects of nanomaterials present in the environment are presented on the basis of the scientific literature in the field.

Background Clostridioides difficile infection (CDI) is the most common cause of hospital-acquired diarrhea. There is little available data regarding risk factors of CDI for patients who undergo cardiac surgery. The study evaluated the course of CDI in patients after cardiac surgery. Methods Of 6,198 patients studied, 70 (1.1%) developed CDI. The control group consisted of 73 patients in whom CDI was excluded. Perioperative data and clinical outcomes were analyzed. Results Patients with CDI were significantly older in comparison to the control group (median age 73.0 vs 67.0, P = 0.005) and more frequently received proton pump inhibitors, statins, β-blockers and acetylsalicylic acid before surgery (P = 0.008, P = 0.012, P = 0.004, and P = 0.001, respectively). In addition, the presence of atherosclerosis, coronary disease and history of malignant neoplasms correlated positively with the development of CDI (P = 0.012, P = 0.036 and P = 0.05, respectively). There were no differences in the type or timing of surgery, aortic cross-clamp and cardiopulmonary bypass time, volume of postoperative drainage and administration of blood products between the studied groups. Relapse was more common among overweight patients with high postoperative plasma glucose or patients with higher C-reactive protein during the first episode of CDI, as well as those with a history of coronary disease or diabetes mellitus (P = 0.005, P = 0.030, P = 0.009, P = 0.049, and P = 0.025, respectively). Fifteen patients died (21.4%) from the CDI group and 7 (9.6%) from the control group (P = 0.050). Emergent procedures, prolonged stay in the intensive care unit, longer mechanical ventilation and high white blood cell count during the diarrhea were associated with higher mortality among patients with CDI (P = 0.05, P = 0.041, P = 0.004 and P = 0.007, respectively). Conclusions The study did not reveal any specific cardiac surgery-related risk factors for development of CDI.

The aim of this study was to determine the influence of Eisenia fetida vermicompost (VC) added to forest nursery soil. The chemical reaction in the soil and selected microorganisms, such as bacteria, fungi and nematodes, were assessed. Larch seedlings were cultivated for 2 years in pots with nursery soil as a control and VC-amended soil in two doses: 10% (V10) and 20% (V20) v/v. One important observation was the connection between the addition of VC and the improvement of the plant's biometry and a much higher level of mycorrhization with increasing Suillus sp. Vermicompost modified the nematode community by reducing plant parasitic nematodes, and significantly increasing bacterial and fungivorous, as well as predatory nematodes. Actinomycetes bacteria, which were present in a proportion of 2.2% in the control soil, increased to 10.5% in V10, and to 5.4% in V20. Bacillus spp. increased along with the amount of VC from

Introduction: The skin of newborns and infants is not fully developed, therefore, it seems particularly important to use in this group products that are safe and free from sensitizing ingredients. Aim of the study: An analysis of skin care products for newborns and infants available on the Polish market with regard to the presence of ingredients with known sensitizing potential. Material and methods: Declared contents of 106 skin care products for newborns and infants: 72 ‘leave-on’ and 34 ‘rinse-off’ cosmetics were analysed for the presence of ‘problematic’ fragrances and preservatives as listed in the Cosmetics Directive (Annex III and VI). Results: Three hundred and sixty-five unique substances including 35 ‘problematic’ substances were identified: 15 (4.1%) fragrances and 20 (5.5%) preservatives. At least one ‘problematic’ fragrance occurred in 91 (85.8%) products, most frequent was linalool, at least one ‘problematic’ preservative occurred in 55 (51.9%), phenoxyethanol was most frequent. Fragrance compositions of undisclosed ingredients hidden under a general cryptonym ‘Parfum’/’Fragrance’ were present in 88 (83%) cosmetic products. Among the analyzed preparations, only 7 (6.6%) did not contain substance with known sensitizing potential. Conclusions: Almost all skin care products for newborns and infants contain ingredients of known sensitizing potential. Most products also contain fragrance compositions hidden under a general cryptonym ‘Parfum’/’Fragrance’ which makes an assessment of their safety profile impossible. The presence of ‘problematic substances’ in almost all cosmetics for newborns and infants confirms the need for further analysis, preventive measures and education of parents and physicians on the dangers of cosmetics use in children.

Performing Monte Carlo simulations we study the temperature dependent self--organization of magnetic moments coupled to itinerant electrons in a finite--size one--dimensional nanostructure proximitized to a superconducting reservoir. At low temperature an effective interaction between the localized magnetic moments, that is mediated by itinerant electrons, leads to their helical ordering. This ordering, in turn, affects the itinerant electrons, inducing the topologically nontrivial superconducting phase that hosts the Majorana modes. In a~wide range of system parameters, the spatial periodicity of a spiral order that minimizes the ground state energy turns out to promote the topological phase. We determine the correlation length of such spiral order and study how it is reduced by thermal fluctuations. This reduction is accompanied by suppression of the topological gap (which separates the zero-energy mode from continuum), setting the upper (critical) temperature for existence of the Majorana quasiparticles. Monte Carlo simulations do not rely on any ansatz for configurations of the localized moments, therefore they can be performed for arbitrary model parameters, also beyond the perturbative regime., Comment: 14 pages, 13 figures, revtex

Silver and titanium dioxide nanoparticles (AgNPs and TiO2NPs) are highly useful, but they are also a significant reason for concern as they exert toxicity. The goal of research was to assess the role of three kinds of NPs in concentrations of 100 mg L−1 on early growth plants (wheat, flax) and bacterial community in rhizoplane. Titanium (IV) oxide anatase (TiO2NPs1) and titanium (IV) oxide nanopowder (TiO2NPs2) are commercial products. A suspension of AgNPs was prepared via a procedure of reduction with tannic acid. The response of Monocot and Dicot growth form plants to the tested NPs was different. Germination and seedling growth of wheat treated with TiO2NPs1 was better. The response of flax to NPs was noted as an increase of chlorophyll content. The bacterial community in wheat rhizoplane was not significantly modified, but there was a declining trend. In turn, a difference in the surface charge of NPs had an influence on the total bacterial community in Dicot rhizoplane. Positively charged TiO2NPs2 significantly decreased the quantity of total bacteria in contrast to negatively charged AgNPs and TiO2NPs1 which increased it. A qualitative analysis did not confirm the influence of the surface charge of NPs on an increase/decrease in the quantity of Pseudomonas and Bacillus bacteria, but did show that there was no toxicity of the tested NPs to the plant growth-promoting bacteria community. The rhizoplane microbiome was dependent on the species of plant, and the bacteria found in the communities are sensitive to NPs to a varying degree.

INTRODUCTION Acute gastroenteritis (AGE) is considered one of the most common reasons for hospitalization and the third leading cause of death related to infectious diseases in children. The incidence and prevalence of campylobacteriosis is lower in Poland than in other parts of the European Union. THE AIM OF THE STUDY The aim of the study was to investigate the epidemiology and clinical features of AGE in hospitalized children. MATERIALS AND METHODS The study population comprised 462 consecutive patients with AGE, hospitalized in the Department of Pediatric Infectious Diseases and Hepatology at John Paul II Hospital in Krakow during 2016. After admission in the hospital, the patients’ stool samples were collected and tested for viral or bacterial pathogens. The specimens were analyzed using classical cultural methods and qualitative immunochromatographic assays for pathogens screening. The patients’ age, sex, etiological factor, seasonal distribution, hospital length of stay and symptoms of disease were collected retrospectively. RESULTS The median age of AGE patients was 3.0 years [1.5-5.5]. Eighty percent of all AGE cases occurred in patients under 5 years of age (p

We investigate the single and multiple defects embedded in a superconducting host, studying interplay between the proximity induced pairing and interactions. We explore influence of the spin-orbit coupling on energies, polarization and spatial patterns of the bound (Yu-Shiba-Rusinov) states of magnetic impurities in 2-dimensional square lattice. We also address the peculiar bound states in the proximitized Rashba chain, resembling the Majorana quasiparticles, focusing on their magnetic polarization which has been recently reported by S. Jeon et al., [Science 358, 772 (2017)]. Finally, we study leakage of these polarized Majorana quasiparticles on the side-attached nanoscopic regions and confront them with the subgap Kondo effect near to the singlet-doublet phase transition., 10 pages, 9 figures

Durum wheat (Triticum turgidum var. durum) is an important crop in Europe, particularly in the Mediterranean countries. Fusarium head blight (FHB) is considered as one of the most damaging diseases, resulting in yield and quality reduction as well as contamination of grain with mycotoxins. Three winter durum wheat cultivars originating from Austria, Slovakia, and Poland were analyzed during 2012–2014 seasons for FHB incidence and Fusarium mycotoxin accumulation in harvested grain. Moreover, the effects of sowing density and delayed sowing date were evaluated in the climatic conditions of Southern Poland. Low disease severity was observed in 2011/2012 in all durum wheat cultivars analyzed, and high FHB occurrence was recorded in 2012/2013 and 2013/2014 seasons. Fusarium graminearum was the most abundant pathogen, followed by Fusarium avenaceum. Through all three seasons, cultivar Komnata was the most susceptible to FHB and to mycotoxin accumulation, while cultivars Auradur and IS Pentadur showed less symptoms. High susceptibility of cv. Komnata was reflected by the number of Fusarium isolates and elevated mycotoxin (deoxynivalenol, zearalenone, and moniliformin) content in the grain of this cultivar across all three seasons. Nivalenol was identified in the samples of cv. Komnata only. Genotype-dependent differences in FHB susceptibility were observed for the plants sown at optimal date but not at delayed sowing date. It can be hypothesized that cultivars bred in Austria and Slovakia show less susceptibility towards FHB than the cultivar from Poland because of the environmental conditions allowing for more efficient selection of breeding materials. Electronic supplementary material The online version of this article (10.1007/s00114-017-1528-7) contains supplementary material, which is available to authorized users.

An assessment of the influence of water nanosilver suspension was made at a concentration of 10 mg·L−1 on biological material (i.e., vegetative mycelium and conidia of Isaria fumosorosea entomopathogen) on a background of the silver nitrate ionic form used. Conidia of I. fumosorosea treated with silver nitrate for more than 168 h were completely deactivated. The application of nanosilver on Isaria hyphae resulted in a quantitative limitation of mycelium growth and its weaker sporulation after culturing compared to the control. The pathogenicity of a conidial suspension obtained from such culturing towards test insects did not diverge from that observed in the standard culture. No obvious toxic effects of nanosilver were observed on I. fumosorosea conidia. Isaria conidia, after exposure to nanosilver over a period between 1 and 800 h, initially demonstrated weaker vegetative mycelium formation in culture on solid medium and, as a consequence, this mycelium often sporulated in a poorer manner. In one case, ...

The purpose of this study was to examine the effect of silver nanoparticles (AgNPs) produced using the high-voltage arc discharge method on the growth and metabolism of common wheat seedlings. Additionally, a simultaneous assessment of the AgNP-induced reduction in seedling infection by Fusarium culmorum (Fc) was performed. AgNP- and Fc-treated seedlings indicated that both factors considerably inhibited their growth. A significant Fc-induced reduction in seedling blight was observed following treatment with AgNPs; however, treatment with nanoparticles was also accompanied by a serious disintegration of the cell membranes of roots. Moreover, treatment with AgNPs increased the quantum efficiency of energy trapping in the PSII reaction centre (Fv/Fm) with a simultaneous decrease in energy dissipation in the form of heat. Induction of photosynthesis in the presence of AgNPs did not affect height but was reflected in higher total dry weight. Moreover, analysis of antioxidant enzyme activity typical for the stress response indicated the toxicity of AgNPs treatment compared to Fc treatment. Seedlings exposed to AgNP activity demonstrated accumulation of Ag in roots and its translocation to aerial parts, while the pathogen reduced both accumulation and translocation of this element.

The occurrence of stem-base diseases in two cultivars of winter wheat were evaluated in a 3-year experiment, using two agrotechnology levels. The two cultivars evaluated were durum wheat of the Komnata cultivar and common wheat of the Ostka Strzelecka cultivar. The highest intensity was noted in the occurrence of two diseases of the complex, i.e. Fusarium foot rot and eyespot. The examined cultivars were characterized by a similar susceptibility to these diseases. There was an observed difference - a slightly higher susceptibility by the Komnata as opposed to the Ostka Strzelecka cultivar - but it was not significant statistically. Significant differentiation in infestation was noted for other experimental factors like cultivation season and the agrotechnology level. Intensification of the occurrence of both stem-base diseases in the experimental seasons did not affect the mean amount and quality of the yield obtained in the experiment.

A disk-diffusion method experiment assessed the impact of nanosilver on production of secondary metabolites (pigments) by the Fusarium culmorum fungus. Nanosilver colloidal particles in water have been obtained by the use of a method based on high voltage electric arcs between silver electrodes. The silver nanoparticles size in colloid ranged between 15 and 100 nm and 7, 35 and 70 ppm concentration. Nanosilver modifies the metabolism of the researched F. culmorum strain. Coming into contact with nanosilver colloids induces more intensive mycelia pigmentation correlated with nanosilver concentration levels. The performed analysis of metabolites indicates that under the influence of nanosilver fungi biosynthesise aurofusarin more intensively and the conversion of rubrofusarin to aurofusarin is intensified as compared to the control culture. Under the influence of nanosilver F. culmorum intensively biosynthesises an unidentified dye which shares structural features with aurofusarin but which is not produced by fungi in standard cultures.

We investigate the inhomogeneous Rashba chain coupled to a superconducting substrate, hosting the Majorana quasiparticles near its edges. We discuss its subgap spectrum and study how robust are the zero-energy quasiparticles against the diagonal and off-diagonal disorder. Studying the $\mathbb{Z}_2$ topological invariant we show that disorder induced transition from the topologically non-trivial to trivial phases is manifested by characteristic features in the spatially-resolved quasiparticle spectrum at zero energy. We provide evidence for the non-local nature of the zero-energy Majorana quasiparticles, that are well preserved upon partitioning the chain into separate pieces. Even though the Majorana quasiparticles are not completely immune to inhomogeneity we show that they can spread onto other (normal) nanoscopic objects via the proximity effect., 15 pages, 22 figures

We discuss the quantum dot-ring nanostructure (DRN) as canonical example of a nanosystem, for which the~interelectronic interactions can be evaluated exactly. The system has been selected due to its tunability, i.e., its electron wave functions can be modified much easier than in, e.g., quantum dots. We determine many-particle states for $N_e=2$ and $3$ electrons and calculate the 3- and 4-state interaction parameters, and discuss their importance. For that purpose, we combine the first- and second-quantization schemes and hence are able to single out the component single-particle contributions to the resultant many-particle state. The method provides both the ground- and the first-excited-state energies, as the exact diagonalization of the many-particle Hamiltonian is carried out. DRN provides one of the few examples for which one can determine theoretically all interaction microscopic parameters to a high accuracy. Thus the evolution of the single-particle vs. many-particle contributions to each state and its energy can be determined and tested with the increasing system size. In this manner, we contribute to the wave-function engineering with the~interactions included for those few-electron systems., Comment: 13 pages, 12 figures, 1 table; Supplementary Information: 7 pages, 4 figures, 6 tables

We study spin-dependent transport through a quantum nanostructure composed of a quantum dot (QD) surrounded by a quantum nanoring. The nanostructure is side-attached to source and drain electrodes and we assume that the confining potential that forms the nanostructure can be controlled by electrical gating. We demonstrate that depending on the model parameters the system can exhibit positive as well as negative differential conductance (NDC). What is more interesting, these properties can be easily controlled by tuning the applied gate voltage., 12 pages, 10 figures

The aim of the present experiment was to investigate the influence of silver nanoparticles on Fusarium culmorum (W.G. Smith) Sacc. (FC) spores. The silver nanoparticles were produced by the high-voltage arc discharge method. To test the effect of silver nanoparticles on FC spores, 3 parameters were tested. One of these parameters was the vegetative mycelial growth in 2 experiments. The first involved the growth of FC spores on potato dextrose agar (PDA) medium after contact with 0.12–10 ppm of silver nanoparticles, and the second the growth of spores after contact with 0.12–2.5 ppm solutions of silver, but with culturing on 3 types of media (PDA, nutrient-poor PDA, and agar) instead. The next parameter was the formation of spores after the mycelia were cultured. The last parameter was spore germination in a 2.5 ppm solution of silver nanoparticles. A significant reduction in mycelial growth was observed for spores incubated with silver nanoparticles. This relationship was dependent on the incubation time and type of growth medium, but did not depend significantly on the concentration of silver nanoparticles up to 2.5 ppm. The sporulation test showed that, relative to control samples, the number of spores formed by mycelia increased in the culture after contact with silver nanoparticles, especially on the nutrient-poor PDA medium. The 24 h incubation of FC spores with a 2.5 ppm solution of silver nanoparticles greatly reduced the number of germinating fragments and sprout length relative to the control.

We investigate an inhomogeneous one-dimensional nanosystem coupled to macroscopic leads of different temperatures. In particular, we consider a system with an impurity with on-site scattering potential located in the middle of the nanowire. Such an impurity produces oscillations of the density of carriers in its vicinity, the so-called Friedel oscillations. In the equilibrium case these oscillations are symmetric with respect to the position of the impurity. Here, we demonstrate that strongly asymmetric Friedel oscillations occur if the system is far from the equilibrium. We discuss how this asymmetry depends on the model parameters and the difference of the temperatures of the leads.

Wprowadzenie Praca stanowi podsumowanie ankiety przeprowadzonej w ramach programu PEGAZ realizowanego Polsce w 2007 r. Cel Celem pracy jest zebranie informacji dotyczących: mozliwości opieki nad dziecmi z autoimmunologicznym zapaleniem wątroby, doświadczen i wyposazenia ośrodkow sprawujących opieke nad tymi pacjentami oraz szacunkowej liczby pacjentow i ich charakterystyki. Wyniki Ankiety uzyskano z 18 ośrodkow rozmieszczonych rownomiernie na terenie Polski. Wiekszośc ośrodkow dysponuje odpowiednim zapleczem diagnostycznym, choc mogą wystepowac problemy z diagnostyką roznicową choroby Wilsona i niedoboru alfa-1-antytrypsyny oraz badaniami PCR w kierunku zakazen HBV i HCV. Stwierdzono duze zroznicowanie pomiedzy ośrodkami w standardach oceny badania patomorfologicznego. Łącznie w ośrodkach leczonych jest okolo 250–300 dzieci z AZW, co pozwala szacowac czestośc wystepowania choroby na 3–4 przypadki na 100 tys. Wiekszośc pacjentow stanowią dziewczynki, a średni wiek chorych to 11 lat. Zanotowano 6 zgonow, u 11 pacjentow przeszczepiono wątrobe. Wiekszośc pacjentow jest zarejestrowana w ośrodku centralnym, prowadzącym rowniez leczenie transplantologiczne. Wnioski Zebrane dane wskazują, ze w sposob spontaniczny powstal system opieki nad pacjentami z AZW. Wprowadzenie wspolnych standardow postepowania moze poprawic jego funkcjonowanie.

The usual approaches to the reentrant superconductivity are based on the mean field approximation. Here, we investigate this effect carrying out exact diagonalization of finite systems. We have found a non-monotonic field dependence of the pair susceptibility both in the weak and strong coupling limit. This result strongly supports the possible onset of the reentrant superconductivity in the presence of strong magnetic field.

Institute of Physics and Nanotechnology Center, M. Curie-Sklodowska University, Pl. M. Curie-Sklodowskiej 1, 20-031 Lublin, Poland Received 10 January 2007, revised 2 February 2007, accepted 10 February 2007 Published online 9 May 2007 PACS 73.40.Gk, 73.63.–b, 74.50.+r, 74.78.–w There is still no consensus on the mechanism that is responsible for a particle–hole asymmetry observed in scanning tunneling spectroscopy of high-temperature superconductors. According to the most popular hypothesis this asymmetry results from strong Coulomb correlations in a nearly half-filled band. In the present paper we propose another mechanism that leads to such asymmetry. It originates from the cou-pling between the superconductor and the substrate that the system is deposed on. We show that this cou-pling gives rise to the particle–hole asymmetry only in the case of an anisotropic superconductivity.

Transport properties of a gated nanostructure depend crucially on the coupling of its states to the states of electrodes. In the case of a single quantum dot the coupling, for a given quantum state, is constant or can be slightly modified by additional gating. In this paper we consider a concentric dot-ring nanostructure (DRN) and show that its transport properties can be drastically modified due to the unique geometry. We calculate the dc current through a DRN in the Coulomb blockade regime and show that it can efficiently work as a single electron transistor or a current rectifier. In both cases the transport characteristics strongly depends on the details of the confinement potential. The calculations are carried out for low and high bias regime, the latter being especially interesting in the context of current rectification due to fast relaxation processes., Comment: 24 pages, 13 figure

The bioactivity of three kinds of multi-walled carbon nanotubes (MWCNT) towards the conidia of entomopathogenic fungus Isaria fumosorosea was examined in an in vitro study. Commercial—raw and functionalized—carboxylated MWCNT were applied. A fungal conidia suspension was placed in contact with dispersed MWCNT over different time-periods. After contact with the nanomaterial, the conidia were cultured on dishes and both the linear vegetative mycelium growth and the sporulation and germination of the spores derived from the culture were investigated. Also, the pathogenicity of the conidia after contact with MWCNT was examined in relation to test larvae. No fungistatic activity of MWCNT relative to I. fumosorosea conidia was demonstrated. Conidia contact with MWCNT resulted in the following changes in vital processes in the subsequent culture compared to the control standard culture: (1) raw MWCNT limited mycelium inoculation, but the growth rate observed later in the log-phase was more intense; (2) after 24-h conidia contact with all MWCNT types, the mycelium sporulated the most intensively; longer contact resulted in sporulation process limitation. Germination of conidia after contact with the MWCNT was not significantly modified. Raw MWCNT potentiated conidia pathogenicity towards test insects. It was observed that carboxylation of MWCNT reduces the bioactivity of this nanomaterial towards the investigated conidia.

A disk-diffusion method experiment assessed the impact of nanosilver on production of secondary metabolites (pigments) by the Fusarium culmorum fungus. Nanosilver colloidal particles in water have been obtained by the use of a method based on high voltage electric arcs between silver electrodes. The silver nanoparticles size in colloid ranged between 15 and 100 nm and 7, 35 and 70 ppm concentration. Nanosilver modifies the metabolism of the researched F. culmorum strain. Coming into contact with nanosilver colloids induces more intensive mycelia pigmentation correlated with nanosilver concentration levels. The performed analysis of metabolites indicates that under the influence of nanosilver fungi biosynthesise aurofusarin more intensively and the conversion of rubrofusarin to aurofusarin is intensified as compared to the control culture. Under the influence of nanosilver F. culmorum intensively biosynthesises an unidentified dye which shares structural features with aurofusarin but which is not produced by fungi in standard cultures.

The objective of the study was to evaluate the in vitro effect of aqueous suspensions of commercial multi-walled carbon nanotubes (MWCNTs) on spores of three entomopathogenic fungus species of Beauveria bassiana. Spores were placed in contact with MWCNTs for 1, 24, 72 and 216 h and then an in vitro evaluation in the subculture was performed on the linear growth of the vegetative mycelium of the spores after the contact with nanomaterial, as well as its sporulation after completion of the culture. No fungistatic effect of MWCNTs against B. bassiana spores was identified. Modification of vegetative mycelium surface growth in the culture of spores after contact with MWCNTs was mainly due to less effective inoculation, especially when shorter contact times with nanomaterial were applied. For one of the investigated strains, growth stimulation was observed in the culture of spores in contact with nanotubes for 72 and 216 h. Based on the significant intensification of sporulation observed in combination with the longest (216 h) contact with the investigated spore strains before culture with MWCNTs, it can be concluded that the tested nanomaterial constitutes a stress factor and may modify the metabolism of B. bassiana cells. Detailed evaluation of B. bassiana metabolic changes induced by MWCNTs should be conducted.

The aim of the study was an in vitro evaluation of the effect of MWCNTs on the conidia of two strains of entomopathogenic fungus, Metarhizium anisopliae. The study made use of water suspensions of MWCNTs (concentration ∼ 3 mg·mL(-1)) made from commercial nanotubes and centrifuged. The conidia were placed in contact with nanotubes for 240 h. An assessment of MWCNT influence on conidia was performed after 1, 24, 72 and 240 h and focused on the linear growth of vegetative mycelium derived from these conidia, mycelium sporulation in subcultures and pathogenicity. Using TEM imaging, it was demonstrated that carbon nanotubes are able to damage cell membranes of the examined fungi conidia. However, the absence was noted of a significantly fungistatic effect of both MWCNT suspensions on the examined strains with respect to the physiological features in question. The increase in vegetative mycelium effected by spores after contact with MWCNTs was characterized by a slight modification in relation to the control. There was no strong trend (inhibition - stimulation), in relation to the effect of the tested suspension of carbon nanotubes, on the development of the vegetative mycelium in in vitro culture. Sporulation of the mycelium after completion of the culture only occurred in one case (strain Ma73F and culture of spores after 24-h contact with MWCNTs) significantly more intensely than in the controls. With respect to pathogenicity for test insects compared to the control strain, Ma73F spores grown from the longest contact with nanotubes suspensions performed significantly better. On the basis of the calculated of mycelium index growth rates and the time of death of the test insects (LT50), it was found that the adverse effects of water suspension MWCNTs on the spores of M. anisopliae were applied after a short contact with biological material. This indicates unfavorable physical rather than chemical effects on the tested cell. Over time, nanotube aggregation in water suspensions led to changes in their influence on the cells under examination.

The conducting properties of a two-dimensional nanostructure in the form of a quantum dot surrounded by a quantum ring, named afterwords a dot-ring nanostructure (DRN), are discussed. This complex system is a highly controllable object. It was shown that by changing the confinement potential, e.g., by the electrical gating one can change the shape and distribution of the electron wave functions which determine many physical, measurable quantities. In the recent papers [1] we have shown that one can change the spin relaxation time of the spin memory device by orders of magnitude and the absorption cross section from strong to negligible. Such structures have been recently fabricated [2]. The purpose of this study is to demonstrate a highly controllable transport properties of DRN. Conduction through DRN depends crucially on the coupling strength of its states to the leads, what, in turn, depends on the spatial distribution of the electron’s wave functions in DRN. As it was demonstrated in Ref. [1], this distribution can be strongly modified so that the ground and excited states move between the inner dot and the outer ring. In this paper we show that this property can be used to control single-electron DC current through DRN in the Coulomb blockade regime. We show that one can adjust the confinement potential of DRN so that it can be used as: a) single electron transistor b) electrical current rectifier The results indicate an opportunity to optimize specific properties of complex nanostructures by means of sophisticated structural design.

In spite of a lack of acute toxicity of single metal ions, in 96 hour laboratory tests there was along term toxicity against S. carpocapsae and H. bacteriophora nematodes. The 96 hourlaboratory tests were carried out in order to prove possible synergistic and antagonisticinteractions between pairs of metal ions. Thus, the pairs of ions were arranged from each of Al,Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mo(VI), Ni(II), Se(IV), V(V) and Zn on one sideand Mn(II) and Mg on the other. Mn(II) and Mg ions considerably reduced the nematodemortality and increased their infectivity against Galleria mellonella caterpillars.

In spite of a lack of acute toxicity of single metal ions, in 96 hour laboratory tests there was a long term toxicity againstS. carpocapsae andH. bacteriophora nematodes. The 96 hour laboratory tests were carried out in order to prove possible synergistic and antagonistic interactions between pairs of metal ions. Thus, the pairs of ions were arranged from each of Al, Cd, Co(II), Cr(III), Cr(VI), Cu(II), Fe(III), Li, Mo(VI), Ni(II), Sc(IV), V(V) and Zn on one side and Mn(II) and Mg on the other. Mn(II) and Mg ions considerably reduced the nematode mortality and increased their infectivity againstGalleria mellonella caterpillars.