The sonochemical coating of cotton withstands 65 washing cycles at hospital washing standards and retains its antibacterial properties

Hospital-acquired nosocomial infections are a major health, and consequently financial issue, in the world healthcare system. The problem of bacterial infections in general, and in hospitals in particular, has led to extensive scientific and industrial efforts to fabricate antibacterial textiles. A sonochemical coating machine was developed and built and its ability to coat antibacterial nanoparticles (NPs) onto 40–50 meter length of materials on a roll to roll basis at a speed of 22 cm/min. Cotton coated sonochemically with copper oxide nanoparticles (CuO NPs) was found to maintain its antibacterial properties even after 65 cycles of washings according to hospital protocols of hygienic washing (75 °C). This demonstrates the good quality and high stability of this sonochemically produced NPs coating on textiles. Durable antibacterial textiles such as these may be suitable for wide spread use in future hospital environments where hygiene control is of paramount importance.     

Gold nanoparticles deposited capillaries for in-capillary microextraction capillary zone electrophoresis of monohydroxy-polycyclic aromatic hydrocarbons

This article presents the first application of gold nanoparticles deposited capillaries as pre-concentration devices for in-capillary microextraction CZE and their use for the analysis of monohydroxy-polycyclic aromatic hydrocarbons in synthetic urine samples. The successful separation of 1-hydroxypyrene, 9-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene (3-OHbap), 4-hydroxybenzo[a]pyrene and 5-hydroxybenzo[a]pyrene under a single set of electrophoretic conditions is demonstrated as well as the feasibility to obtain competitive ultraviolet absorption LOD with commercial instrumentation. Enrichment factors ranging from 87 (9-OHphe) to 100 (3-OHbap) made it possible to obtain LOD ranging from 9 ng/mL (9-OHphe and 3-OHbap) to 14 ng/mL (4-hydroxybenzo[a]pyrene).     

Multi-way partial least-squares and residual bi-linearization for the direct determination of monohydroxy-polycyclic aromatic hydrocarbons on octadecyl membranes via room-temperature fluorescence excitation emission matrices

Multi-way partial least-squares (N-PLS) is combined to the residual bi-linearization procedure (RBL) for the direct analysis of metabolites of polycyclic aromatic hydrocarbons in urine samples. Metabolite analysis is carried out via a two-step experimental procedure based on solid-phase extraction and room temperature fluorescence spectroscopy. Excitation-emission matrices are recorded from octadecyl (C18) membranes that serve as solid substrates for sample extraction and spectroscopic measurements. Excellent metabolite recoveries were obtained in all cases, which varied from 96.2 ± 1.35% (9-hydroxyphenanthrene) to 99.7 ± 0.49% (3-hydroxybenzo[a]pyrene). Background correction of extraction membranes is carried out with a new alternating least-squares (ALS) procedure adapted to second order data. The performance of N-PLS/RBL is compared to the well-established multivariate curve resolution-alternating least-squares (MCR-ALS) algorithm. Both algorithms provided similar analytical figures of merit, including their ability to handle unknown interference in urine samples. With only 10 mL of sample, the limits of detection varied between 0.06–0.08 ng mL⁻¹ (1-hydroxypyrene) and 0.016–0.018 ng mL⁻¹ (2-hydroxyfluorene). When compared to previously reported univariate calibration data, the limits of detection via N-PLS/RBL and MCR-ALS are approximately one order of magnitude higher. This was somehow expected due to the effect of unexpected components in multivariate figures of merit, i.e. a more realistic approach to the analysis of metabolites in human urine samples.     

Band gap of triglycine selenate,triglycine fluorine beryllate,triglycine sulfate and its variation under γ-irradiation

The band gap for three ferroelectrics (triglycine selenate, triglycine fluorine berryllate and triglycine sulfate) is determined using an optic method. A shift of self-absorption edge towards longer wave lengths is observed when exposed to irradiation by γ rays with a dosage of ∽ (2 ÷ 7) · 10⁷ r as well as corresponding decrease of band gap. The observed changes are connected with the chemical nature of the studied substances.     

In vivo quantification and pharmacokinetic studies of cotinine in mice after smoke exposure by LC–MS/MS

A sensitive analytical method was developed and validated for the quantification of cotinine in mouse plasma after exposure to smoke of 0.5, 1.0, and 1.5 commercially available cigarettes, using liquid chromatography tandem mass spectrometry. The method was validated over a linear concentration range of 0.075–20.0 ng/mL with the R² value being higher than 0.99. Both the precision (coefficient of variation; %) and accuracy (relative error; %) were within acceptable criteria of <15%. The lower limit of quantification (LLOQ) for cotinine was 0.075 ng/mL with sufficient specificity, accuracy, and precision. Following exposure to 0.5, 1.0, and 1.5 cigarette smoke, it was observed that the AUC and the C_max increased linearly as the doses increased. The pharmacokinetics of cotinine was found linear for the range of 0.5–1.5 commercial cigarette smoke. The quantification of the concentration of cotinine in mouse plasma after smoke exposure will facilitate future behavioral and toxicological experiments in animals and may prove useful in predicting cotinine levels in humans during smoking.     

Rearrangement of the domain structure of cobalt- and chromium-doped triglycine sulfate crystals

The paper reports the results of studies of repolarization and rearrangement of the domain structure of triglycine sulfate (TGS) crystals containing two impurities, cobalt and chromium. The introduction of these impurities hinders the repolarization of TGS crystals and causes their spontaneous polarization to decrease, the coercive field to increase, and displacement fields to form.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 63–66, April, 1991.     

Achieving second order advantage with multi-way partial least squares and residual bi-linearization with total synchronous fluorescence data of monohydroxy–polycyclic aromatic hydrocarbons in urine samples

An attractive approach to handle matrix interference in samples of unknown composition is to generate second- or higher-order data formats and process them with appropriate chemometric algorithms. Several strategies exist to generate high-order data in fluorescence spectroscopy, including wavelength time matrices, excitation–emission matrices and time-resolved excitation–emission matrices. This article tackles a different aspect of generating high-order fluorescence data as it focuses on total synchronous fluorescence spectroscopy. This approach refers to recording synchronous fluorescence spectra at various wavelength offsets. Analogous to the concept of an excitation–emission data format, total synchronous data arrays fit into the category of second-order data. The main difference between them is the non-bilinear behavior of synchronous fluorescence data. Synchronous spectral profiles change with the wavelength offset used for sample excitation. The work presented here reports the first application of total synchronous fluorescence spectroscopy to the analysis of monohydroxy-polycyclic aromatic hydrocarbons in urine samples of unknown composition. Matrix interference is appropriately handled by processing the data either with unfolded-partial least squares and multi-way partial least squares, both followed by residual bi-linearization.     

Room-temperature fluorescence spectroscopy of monohydroxy metabolites of polycyclic aromatic hydrocarbons on octadecyl extraction membranes

Urine analysis of monohydroxy metabolites is recognized as an accurate assessment of human exposure to polycyclic aromatic hydrocarbons. Despite the sophisticated arsenal of analytical tools, monitoring of monohydroxy metabolites via simple, cost effective and direct methods of analysis still remains a challenge. This article evaluates the analytical potential of solid-phase extraction room-temperature fluorescence spectroscopy for the problem at hand. Extraction membranes serve the dual purpose of sample pre-concentration and solid substrate for RTF measurements. The potential of our proposition is demonstrated with the analysis of 2-hydroxy-fluorene, 1-hydroxy-pyrene, 3-hydroxy-benzo[a]pyrene and 9-hydroxy-phenanthrene in synthetic urine samples. Signal reproducibility is improved with the aid of a sample holder specifically designed for the manual optimization of luminescence signals. Background correction of solid substrates is carried out with the aid of Asymmetric Least Squares. Recovery values for the studied metabolites varied from 99.0 ± 1.2% (3-hydroxy-benzo[a]pyrene) to 99.9 ± 0.05% (1-hydroxy-pyrene). With only 10 mL of urine sample, the limits of detection varied from 57 pg mL⁻¹ (2-hydroxy-fluorene) to 2 pg mL⁻¹ (1-hydroxy-pyrene). Additional figures of merit include a simple experimental procedure for routine screening of numerous samples and compatibility with portable instrumentation for field analysis. Because of the non-destructive nature of fluorescence measurements, membranes can be brought to the lab for subsequent elution and confirmation of compounds via high-resolution techniques.