Effects of single-walled carbon nanotubes on the optical and photo-conductive properties of their composite films with regio-regular poly(3-hexylthiophene)

The effect of a small admixture of single-walled carbon nanotubes (SWNTs) HiPCO (high pressure carbon monoxide) (from 0.5 to 2 wt%) on the supramolecular structure in regio-regular poly(3-hexylthiophene) (RR-P3HT) thin films is studied and their optical and photoconductivity properties are investigated. It is demonstrated that the presence of such small amounts of nanotubes improves the structural organization in the films as evidenced by X-ray diffraction (XRD) studies. This is confirmed by UV–visible optical absorption investigations which clearly show a better conjugation of P3HT in the presence of nanotubes. In Raman spectra of composites, changes in intensities and frequencies of the radial breathing modes are observed upon addition of nanotubes. This can be rationalized by a modification of the resonance conditions caused by a selective dispersion and wrapping of SWNTs via π-interaction (π-stacking). As a consequence of these interactions, a dramatic photoluminescence (PL) quenching is observed which becomes more and more pronounced with increasing the nanotube content. This implies a fast photo-induced electron transfer favoured by a large area of the SWNTs/P3HT interface and strong interactions between these two components. An increase in the composite photocurrent by at least one-order of magnitude, as compared to the case of pure P3HT film, is the most pronounced effect of this electron transfer. These two effects are of crucial importance for the application of the investigated composites in bulk hetero-junction photovoltaic cells (BHJPCs) and organic photo-detectors (OPDs).     

Cooperation patterns in science within Europe: the standpoint of small countries

This article is concerned with the cooperation patterns of science among European countries from the viewpoint of small countries. This is an issue, which empirical literature so far has overlooked, but which is still relevant for understanding the implications of integration processes in EU. We have replicated and expanded in sample, indicator and time dimensions the empirical analysis suggested by Frenken (Economic Systems Research 14(4):345–361, 2002) for assessing the homogeneity of cooperation patterns among European countries. We find that small states are less homogenously collaborating with all countries in the European research system and their intra-national research cooperation is also more fragmented. Our analysis reveals the outcomes of cooperation processes, and also highlights the factors such as research funding and research specialisation that can impact the results of the connectivity measurement. We also show that the results are sensitive to the size and measurement of the science system.     

Geostatistics applied to mine waste characterization at Leadville,Colorado, USA

ABSTRACT

This paper will describe the process of identifying lead contaminated soil areas exceeding a certain threshold at a historical mining district using geostatistical tools. For this purpose, lead concentration samples coming from Leadville County, Colorado were chosen as the data sets to be examined. In order to check integrity of data files, posting of the data values at sample locations is performed on each of the four data sets available. Statistical analysis is used for identifying possible different populations within the study area Based on the statistical results, the data sets were subdivided into four different populations as they relate to residential domains. More detail geostatistical analysis of data set representing the City of Leadville domain (CL) is performed Variogram analysis is used to characterize spatial variability on the data sets within CL limits. Generation of variograms for such data sets and identification of their parameters such as sill, nugget, range, and anisotropy ratios is performed. Once these parameters are identified, variogram modeling is accomplished. A significant spatial correlation is found within CL boundaries and two geostatistical estimation techniques named ordinary kriging and indicator kriging are applied to determine level of contamination at unsampled locations exceeding 3500 PPM threshold. Such techniques are tested by cross validation in order to check possible overestimation bias over 3500 PPM threshold. Indicator Kriging was found to be the best estimator which provided the minimum overestimation bias of areas of contamination exceeding 3500 PPM threshold compared with ordinary kriging.     

Cloxacillin‐induced seizure in a hemodialysis patient

We are reporting a cloxacillin‐induced seizure in a patient with stage 5 chronic kidney disease requiring hemodialysis. To our knowledge, there are no published case reports of seizures induced by parenteral cloxacillin in hemodialysis patients. A young hemodialysis female was admitted to the hospital with decreased level of consciousness. Blood cultures revealed methicillin‐sensitive Staphylococcus aureus where cloxacillin 2 g intravenously every 4 hours was initiated. Head computed tomography (CT) was not significant. After 14 hours of cloxacillin therapy (4 doses), the patient demonstrated tonic/clonic seizure activity, where phenytoin and lorazepam were initiated. The anti‐seizure medications partially reduced seizure activity. Once the cloxacillin was discontinued, the seizures stopped. Two weeks later, all anti‐seizure medications were stopped with no further seizure activity. Cloxacillin elimination in hemodialysis patients is similar to patients with normal kidney function. Although cloxacillin does not significantly cross the blood–brain barrier, the correlation between the start of seizures and cloxacillin initiation was confirmed by the negative CT and blood chemistry laboratory results. Moreover, seizure activity was terminated upon discontinuation of cloxacillin. Although further investigation for the cause of such seizures is warranted, clinicians should use caution when giving high doses of cloxacillin in hemodialysis patients.     

Nutritional constituents,phytochemical profiles, <Emphasis Type="Italic">in vitro</Emphasis> antioxidant and antimicrobial properties,and gas chromatography–mass spectrometry analysis of various solvent extracts from grape seeds (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

The present study revealed that the nutritive value of grape seeds (Vitis vinifera L.) was 383.55±0.13 Kcal/100 g, with magnesium as the most abundant mineral element (70.44±0.88 mg/L). The maximum phenolic (392.58±1.70mg of GAE/g), flavonoid (256.16±1.60 mg of QE/g), and tannin (30.95±0.17mg of CE/g) contents were also found in the ethanol, dichloromethane, and hexane extracts, respectively. The major phytochemical compounds in the ethyl acetate extract were identified via gas chromatography–mass spectrometry (GC–MS) analysis. The ethanol extract has the highest antioxidant activity (IC₅₀=140±1.20 μg/mL for DPPH, 145.28±0.45mg α-tocopherol/g for total antioxidant capacity, and EC₅₀=80±1.41 μg/mL for ferric-reducing power assays). For β-carotene test, the highest antioxidant activity was obtained in the hexane extract. A satisfactory antimicrobial activity was found against a panel of microorganisms with the ethyl acetate extract as the best antimicrobial agent. Additionally, it was found that the bactericidal concentration required for the grape seed extract to kill Listeria monocytogenes should be less than 12.50 mg/mL (minimum inhibitory concentration=4).     

Design and numerical analysis of interdigitated radiating-strips electrode for uniform 3D dielectrophoretic patterning of liver cells

Microsystem Technologies - This paper presents the design and numerical analysis of a new three-dimensional (3D) electrode having a non-uniform electric field gradient for dielectrophoretic...     

Electroless synthesis of 3 nm wide alloy nanowires inside Tobacco mosaic virus

We show that 3 nm wide cobalt-iron alloy nanowires can be synthesized by simple wet chemical electroless deposition inside tubular Tobacco mosaic virus particles. The method is based on adsorption of Pd(II) ions, formation of a Pd catalyst, and autocatalytic deposition of the alloy from dissolved metal salts, reduced by a borane compound. Extensive energy-filtering TEM investigations at the nanoscale revealed that the synthesized wires are alloys of Co, Fe, and Ni. We confirmed by high-resolution TEM that our alloy nanowires are at least partially crystalline, which is compatible with typical Co-rich alloys. Ni traces bestow higher stability, presumably against corrosion, as also known from bulk CoFe. Alloy nanowires, as small as the ones presented here, might be used for a variety of applications including high density data storage, imaging, sensing, and even drug delivery.     

Tomatidine and Patchouli Alcohol as Inhibitors of SARS-CoV-2 Enzymes (3CLpro,PLpro and NSP15) by Molecular Docking and Molecular Dynamics Simulations

Considering the current dramatic and fatal situation due to the high spreading of SARS-CoV-2 infection, there is an urgent unmet medical need to identify novel and effective approaches for prevention and treatment of Coronavirus disease (COVID 19) by re-evaluating and repurposing of known drugs. For this, tomatidine and patchouli alcohol have been selected as potential drugs for combating the virus. The hit compounds were subsequently docked into the active site and molecular docking analyses revealed that both drugs can bind the active site of SARS-CoV-2 3CLpro, PLpro, NSP15, COX-2 and PLA2 targets with a number of important binding interactions. To further validate the interactions of promising compound tomatidine, Molecular dynamics study of 100 ns was carried out towards 3CLpro, NSP15 and COX-2. This indicated that the protein-ligand complex was stable throughout the simulation period, and minimal backbone fluctuations have ensued in the system. Post dynamic MM-GBSA analysis of molecular dynamics data showed promising mean binding free energy 47.4633 ± 9.28, 51.8064 ± 8.91 and 54.8918 ± 7.55 kcal/mol, respectively. Likewise, in silico ADMET studies of the selected ligands showed excellent pharmacokinetic properties with good absorption, bioavailability and devoid of toxicity. Therefore, patchouli alcohol and especially, tomatidine may provide prospect treatment options against SARS-CoV-2 infection by potentially inhibiting virus duplication though more research is guaranteed and secured.