Spectrometry Method Research Articles

Spectral transmittance changes in a PCM glass block affected by an artificial radiation source

Adaptive principles based on latent thermal energy storage together with its optimal modulation of optical properties in transparent façade systems represent one of the challenging solutions for reducing the energy consumption of buildings. Properly incorporated phase change material (PCM) may be a potential technique for passive solar system applications. This study focuses on the analysis of PCM’s optical changes on innovative building envelope components. A stable radiation source that most closely approximates the conditions of sunlight is essential for the characterization of new solar thermal systems. Hence the intensity and spectral distribution of the light source are the most important factors corresponding to natural sunlight. This contribution stems from previous experimental research focused on the investigation of the changes in the transparency of the PCM material, which is the result of the phase transformation from solid to liquid and vice versa under radiation exposure. The main challenge is to characterize the spectral optical properties in the PCM glass system. Accordingly, optical changes were analyzed experimentally using the spectrometry method. The measurements are based on a comparison of clear and PCM-filled glass blocks, affected by artificial radiation in a laboratory. The results revealed that PCM glass block may act as near-infrared absorbing and at the same time a highly transparent system in the visible region compared to the conventional air-based systems.

Comparison of lithium borate fusion and four-acid digestions for the determination of whole-rock chemistry – implications for lithogeochemistry and mineral exploration

Mining and exploration companies routinely use four-acid digestion (4AD), inductively coupled plasma, atomic emission spectra/mass spectrometry methods from commercial assay laboratories for analysing drill and rock samples for lithogeochemical assessment and resource reporting. This method is also known to exhibit lower recovery of elements hosted by resistate minerals. To assess the impact of lower recoveries on lithogeochemical interpretation, a suite of commonly used elements for lithogeochemical analysis (high-field-strength elements Zr, Hf, Nb, Ta, Ti and Eu and transition elements V and Sc) was analysed by 4AD and alkali fusion/acid digestion (AFAD). Lower recoveries in the 4AD relative to the AFAD were recorded for Zr, Hf, Nb, Ta, Ti and Eu; Sc and V reported similar concentrations for both decomposition methods. Despite the lower recoveries for Nb, Ta and Ti, element ratios were largely preserved with the 4AD method due to the recoveries covarying at a 1:1 ratio. A plot of Ti/Nb against V/Sc was found to be largely unaffected by decomposition method, producing similar compositional classifications between the two digestion methods. Use of the Eu anomaly (Eu/Eu*) to determine plagioclase fractionation was also found to be unaffected by decomposition method. In contrast, a standard Zr/Ti v. Nb/Y discrimination plot produced incorrect classifications with 4AD producing more mafic and alkaline classifications relative to the AFAD method. Magmatic fertility interpretations utilizing Zr/Hf were also found to be affected in the 4AD results due to the lower recovery of Zr relative to Hf. This resulted in a bias in the 4AD results and produced false-positive anomalism in fertility assessments. Multiple decomposition methods including combinations of acid and fusion methods are recommended for lithogeochemical analysis utilizing large regions of the periodic table. However, if only 4AD data are available, plots such as Ti/Nb v. V/Sc and Nb/Ta, which preserve their ratios, can be used for lithogeochemical classification. Supplementary material: Wholerock geochemical data and detailed methods are available at https://doi.org/10.6084/m9.figshare.c.6444444

Biofilm and antimicrobial resistance profile of extended-spectrum β-lactamase (ESBL) and AmpC β-lactamase producing Enterobacteriaceae in vegetables and salads

This study characterized 360 vegetables and salad samples for extended-spectrum beta-lactamase (ESBL)- and AmpC-beta-lactamase-producing Enterobacteriaceae. The isolated bacteria species were processed for beta-lactamase production, antimicrobial resistance (AMR) and other virulence potentials following standard microbiological and spectrometry methods. The ESBL and AmpC-beta-lactamase-producing bacteria were positive in 16/360 (4.4%) and 4/360 (1.1%) of the vegetable samples, respectively. Molecular identification of the bacterial isolates revealed them as follows: 37 E. coli, 6 Klebsiella pneumoniae and 4 Klebsiella variicola. The total number of ESBL-producing enterobacterial phenotypes was 38, while the AmpC-beta-lactamase-producing enterobacterial phenotype was 9. The beta-lactamase-producing enterobacterial morphotypes revealed that 16/47(34.0%) were rough and moist morphotypes, 25/47(53.2%) were rough and dry morphotypes, while 6/47(12.8%) were smooth and white morphotype. The biofilm profile included strong biofilm 41(87.2%), moderate biofilm 4(8.5%) and weak biofilm 2(4.3%), as all the isolates formed biofilm on LB broth. Fourteen multi-drug resistance (MDR) phenotypes were observed in the beta-lactamase-producing E. coli isolates. A total of 40/47(85.1%) isolates had ≥1 β-lactamase gene and other AMR genes, with the blaCTX-1 being the most prevalent. Our findings conclude that food vegetables are important reservoirs of beta-lactamase-producing enterobacteria and a potential health risk to consumers of unprocessed vegetables.

The synthesis of decyl-o-phenanthrolinium organic salt and a study of the impact of anion type on in vitro antibacterial activities

According to evidence in the literature, organic salts have an affinity for biological membranes that makes them easily absorbed into cells and capable of having a wide range of biological effects, such as broad antibacterial potential and anticancer activity. The present work describes the preparation of three organic salts with a common decyl-1,10-phenanthrolinium cation ([C22H25N2]+) differing in the anions (Br−, PF6− and (CF3SO2)2N−). The synthesis was confirmed using spectrometry methods (NMR (1H 13C, 19F, 31P), ESI MS, Uv-Vis), CHNSBr elemental and thermal analysis as well as conductivity measurements. In vitro biological activities were tested on two Gram-positive (Staphylococcus aureus (S. aureus), Streptococci pyogenes (S. pyogenes)) and two Gram-negative (Escherichia coli (E. Coli) and Klebsiellae pneumoniae (K. Pneumoniae)) bacteria and compared with a commercial antibiotic (Gentamicin). The salt with the halide anion demonstrated better inhibition activities than the commercially available gentamicin. Their ion-conductivity in ethanol was found to decrease in the order [C22H25N2][PF6], [C22H25N2][(CF3SO2)2N] and [C22H25N2]Br while, their thermal stability was found to increase in the order [C22H29N2]Br, [C22H29N2][PF6], and [C22H29N2][(CF3SO2)2N]. The minimum inhibitory concentration (MIC) values show that the salts could inhibit bacterial growth at concentrations as low as 50 μg/L. Passing the cytotoxicity investigations, these salts can be considered as alternative antibiotics in combating the emerging drug resisting bacteria.

Antimicrobial activity and constituents of the leaf essential oil of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam

Syzygium plants are known as sources of biologically active substances. The essential oils constituents and antimicrobial activity of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam are being reported. Essential oils were obtained by hydrodistillation of the leaves of S. petelotii and S. syzygioides collected from Pù Hoạt Nature Reserve, Vietnam. The constituents of the essential oils were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated by microdilution broth susceptibility assay. The results indicate that γ-guaiene (24.1%), β-caryphyllene (9.3%), α-pinene (7.8%), and β-pinene (6.1%) were the major compounds of S. petelotii. The main constituents of S. syzygioides were caryophyllene oxide (14.8%), α-pinene (10.6%), β-pinene (6.6%) and spathulenol (6.4%). The essential oil of S. petelotii showed pronounced antimicrobial activity against Pseudomonas aeruginosa ATCC27853 and Enterococcus faecalis ATCC299212, with minimum inhibitory concentration (MIC) values of 16.0 μg/mL and 64.0 μg/mL, respectively. The essential oil of S. syzygioides only displayed activity towards Pseudomonas aeruginosa ATCC27853 with MIC value of 32.0 μg/mL. Both essential oils exhibited antimicrobial activity towards Bacillus cereus ATCC14579 (MIC value, 128.0 μg/mL), and anti-candidal action against Candida albicans ATCC10231 with MIC value of 64.0 μg/mL. The chemical compositions and antimicrobial activity of essential oils of S. petelotii and S. syzygioides are being reported for the first time.

Lindera Essential Oils from Vietnam: Antimicrobial Activity and Constituents of the Leaf of Lindera chunii Merr. (Lauraceae) Essential Oils and Chemotaxonomy

Lindera chunii Merr. is an important member of the Lauraceae family of plants which are known for their medicinal values. In this research article, the chemical constituents and antimicrobial activity of essential oils from the leaves of L. chunii grown in Vietnam were reported. The essential oil was obtained by hydrodistillation of the leaves of L. chunii while the constituents were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated using a microdilution broth susceptibility assay. The constituents occurring in higher amounts in the leaf essential oil of L. chunii were mainly the monoterpene hydrocarbons comprising terpinolene (13.0%), α-pinene (8.0%), β-pinene (7.6%), camphene (7.3%), β-phellandrene (7.1%) and myrcene (5.0%). The leaf essential oil of L. chunii inhibited the growth of Enterococcus faecalis ATCC29212, Staphylococcus aureus ATCC25923 and Salmonella enterica ATCC13076, each with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. The corresponding median lethal concentration (IC50) values were 19.45 μg/mL, 20.45 μg/mL and 18.78 μg/mL, respectively. The essential oil also displayed anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 64.0 μg/mL, and IC50 value of 23.12 μg/mL. The antimicrobial activity of L. chunii essential oil was reported for the first time as a confirmation of the traditional uses of the plant in the treatment of microbial infections. Furthermore, the paper discusses the chemotaxonomy of Lindera oil samples.

Electrochemical Production of Ammonia and Urea from Coreduction of Nitrite and Carbon Dioxide at Iron Phthalocyanine Electrodes and Comparison of Analytical Methods

There is rapidly growing interest in the electrochemical reduction of both nitrite and carbon dioxide to mitigate environmental concerns and sustainably produce fuels, chemicals, and fertilizers. Ammonia and urea are key targets in this area, and have been produced simultaneously by coreduction of NO2⁻ and CO2 at a variety of electrocatalysts. The salicylate spectrophotometric method is commonly employed to quantify both products, with urea determined by difference following decomposition with urease. However, this method can be influenced by numerous interferences and matrix effects. Here the electrochemical coreduction of NO2⁻ and CO2 at iron phthalocyanine electrodes has been investigated in order to accurately determine the ammonia and urea production. Urea concentrations were determined by salicylate, diacetyl monoxime and liquid-chromatography-mass spectrometry methods, while the salicylate method and nuclear magnetic resonance spectroscopy were used to determine ammonia. Urea was produced at low overpotentials, with a maximum faradaic yield of 5.8% at −0.047 V vs RHE, while a maximum 85% yield of ammonia occurred at −0.347 V. It is shown that the salicylate method can provide accurate ammonia and urea analyses when a standard addition method is employed, reaction conditions are carefully controlled and the accuracy of calibration slopes are verified.

СРАВНИТЕЛЬНАЯ ОЦЕНКА МЕТОДОВ ОПРЕДЕЛЕНИЯ ПЕРМАНГАНАТА КАЛИЯ В ФАРМАКОПЕЙНЫХ ПРЕПАРАТАХ

Comparative analysis of methods of quantitative determination of potassium permanganate was conducted. The spectrometry method is comparable to iodometry in a number of its criteria and can be used for pharmaceutical analysis. It is also more technological and expressive.

ИССЛЕДОВАНИЕ КОМПОНЕНТНОГО СОСТАВА УГЛЕКИСЛОТНОГО ЭКСТРАКТА ЛИМОННИКА КИТАЙСКОГО СЕМЯН

Schisandra chinensis (Turcz.) Baill. of the Schisandraceae family is a bright representative of medicinal plants from the group of classical plant adaptogens. Schisandra chinensis seeds are an official medicinal plant raw material included in the State Pharmacopoeia of the Russian Federation of the 14th edition, on the basis of which it is possible to create new medicines in modern dosage forms capable of having an adaptogenic and general ionizing effect on the human body. However, in the domestic pharmaceutical market, Schisandra preparations are presented only in the form of a traditional tincture, the use of which is limited due to objective reasons. According to many authors, the predominant form for Schisandra seeds is its oil form. We have proposed the main parameters for obtaining carbon dioxide extract under supercritical conditions from Schisandra chinensis seeds. Therefore, the main purpose of this work was to study the component composition of supercritical carbon dioxide extract of Schisandra chinensis seeds. Using the gas chromatography/mass spectrometry method, 41 compounds belonging to various classes were identified in the studied Schisandra extract. It was experimentally established that the content of monoterpenes was 17,38 %, sesquiterpenes 22,45 %, terpenoids (alcohols, esters, ketones) – 14,99 %) and aromatic substances – 1,66 %. The obtained results also indicate the dominant presence of lignans (43,52 %) in the studied extract. Among which the largest number corresponds to schizandrin (15,68 %) and γ-schizandrin (11,44 %). The component composition of the carbon dioxide extract of Schisandra chinensis seeds, both in terms of the qualitative and quantitative content of biologically active substances, allows it to be further considered as an active composition in the development of new dosage forms.

Synthesis and Biological Evaluation of Azacrownophanes Containing Tetrahydropyridine or Piperidone Subunits

AbstractHerein we presented the synthesis of azacrownophanes containing tetrahydropyridine or piperidone rings. The multicomponent reactions were performed and afforded tetrahydropyridine or piperidone derivatives which strongly depended on used substrates. Structure of tetrahydropyridine and piperidone derivatives was differentiated by spectrometry methods such as IR, HRMS, NMR and single‐crystal Xray diffraction. Eight synthesized compounds were evaluated for their cytotoxicity through Sulforhodamine B (SRB) assay. Three tetrahydropyridine derivatives displayed the most potent cytotoxic activity against Hep‐G2 and Lu‐1 cell lines with the IC50 values around 8 μM and 31.62 μM, respectively. The screening result of antimicrobial activities of all compounds showed negative values at a tested concentration of 50 μg/ml. The ADME study was calculated to provide some useful information about the structure and bioactivity relationship.

Impact of age on in vitro metabolism of clopidogrel: a potential explanation for high on-treatment platelet reactivity in the elderly?

BackgroundHigh on-treatment platelet reactivity has been reported in 30% of patients on clopidogrel and 50% in elderly patients; however, little is known about the mechanisms of this biological resistance. One hypothesis is an age-related impaired hepatic metabolism of the prodrug clopidogrel, leading to a lower formation of its active metabolite (clopidogrel-AM). ObjectivesTo compare the levels of clopidogrel-AM formed in vitro using “old” and “young” human liver microsomes (HLMs) and their consequences on platelet functions. MethodsWe developed an in vitro model using “old” (73.6 ± 2.3 years) and “young” (51.2 ± 8.5 years) HLMs, added to platelet-rich plasma from 21 healthy donors with or without clopidogrel (50 μM) and incubated at 37 °C for 30 (T30) and 45 minutes (T45). Clopidogrel-AM was quantified by liquid chromatography–mass spectrometry/mass spectrometry method. Platelet aggregation was performed by light transmission aggregometry. ResultsThe generation of clopidogrel-AM increased over time and reached concentrations comparable with those reported in treated patients. At T30, mean clopidogrel-AM concentrations were significantly higher with “young” (8.56 μg/L; 95% CI, 5.87-11.24) than with “old” HLMs (7.64 μg/L; 95% CI, 5.14-10.14; P = .002); and at T45, 11.40 μg/L; 95% CI (7.57-15.22) vs 10.63 μg/L, 95% CI (7.10-14.15), P = .02 (n = 21). Despite a significant inhibition of platelet aggregation, no significant difference was found in light transmission aggregometry (adenosine diphosphate, 10 μM) after clopidogrel metabolism by “old” or “young” HLMs, probably because of low sensitivity of the method to small variations of clopidogrel-AM. ConclusionIn this original model combining metabolic and functional approaches, less clopidogrel-AM was produced with HLMs from older patients. This provides support for a decreased CYP450 activity that may contribute to high on-treatment platelet reactivity in elderly patients.

Alteration in glucocorticoids secretion and metabolism in patients affected by cystic fibrosis.

Cystic fibrosis (CF) is an inherited syndrome associated with a mutation in a cystic fibrosis transmembrane conductance regulator gene, composed of exocrine gland dysfunction involving multiple systems that may result in chronic respiratory infections, pancreatic enzyme deficiency, and developmental disorders. Our study describes for the first time the urinary profile of glucocorticoid metabolites and the activity of the enzymes involved in the development and metabolism of cortisol in patients with CF, using a gas chromatography/mass spectrometry method. Data were obtained from 25 affected patients and 70 sex- and age- matched healthy volunteers. We have shown a general decrease in the activity of enzymes involved in the peripheral metabolism of cortisol, such as 11β-hydroxysteroid dehydrogenase type 2, 5α- and 5β-reductases. In contrast, the activity of 11β-hydroxysteroid dehydrogenase type 1, the enzyme that converts cortisone to cortisol, increased. Furthermore, our study found a significant decrease in glucocorticoid excretion in patients with CF. This may suggest adrenal insufficiency or dysregulation of the HPA axis and the development of peripheral mechanisms to counteract cortisol degradation in the case of reduced synthesis of glucocorticoids by the adrenal glands. Furthermore, the activity of 5α-reductase seems to be enhanced only through the backdoor pathway, especially when we taking into consideration 11β-hydroxyandrosterone/11β-hydroxyetiocholanolone ratio which has been shown to be the best differential marker for enzyme activity. CF impairs nutritional effects and energetic balance in patients; thus, our findings suggest the existence of adaptive mechanisms due to limited secretion of adrenal steroids and subsequent diminished amounts of their metabolites in urine. On the other hand, local control of cortisol availability is maintained by enhanced 11βHSD1 activity and its recovery from cortisone in organs and tissues which need this. Steroid hormone dysregulation might be another important factor in the course of CF that should be taken into account when planning an effective and comprehensive therapy.

Numerical Simulation of Carbon Tetrachloride Pollution-Traceability in Groundwater System of an Industrial City

Carbon Tetrachloride (CCL4) is a colorless, volatile, and toxic liquid. Once it pollutes groundwater, it will not only destroy the ecological environment but also negatively affect the functioning of the human liver. An industrial city in eastern China has been contaminated with carbon tetrachloride (CCL4). Due to the complex hydrogeological conditions, it is difficult to determine the pollution source by a single hydrochemical analysis. In order to solve the traceability problem, in this work we established a traceability system by combining hydrochemical analysis, backward tracing, and forward transport, and analyzed the pollution distribution, pollution-source location and pollution-transport characteristic in groundwater, which provided technical support for CCL4-pollution control of groundwater in this area. (1) Groundwater samples were analyzed using the gas chromatography/mass spectrometry method. Through the pollution concentration-field, we identified the location of the pollution center and the concentration value in the northeast and southwest, screening out the monitoring wells exceeding the criteria: HF#1, DJ#19, DJ#7, SS#4, ZF#2, and DY#3. (2) Backward tracing over the past 30 years and 50 years was conducted through MODPATH. Potential polluting factories were identified by comparing the capture area with the historical distribution of factories. (3) Forward solute-transport was performed at the location of these potentially polluted factories. The distribution characteristics of pollutants in limestone layers and the Quaternary layer were analyzed using a simulated concentration-field for August 2012 and October 2016. (4) Comparing the simulated concentration with the observed concentration, the source of CCL4 pollution was inferred to be the textile mill in the 1990s, the steelworks in the 1970s, and the machine-tool plant in the 1970s and 1990s. Based on the concentration–duration curve at the pollution source, the transport characteristics and the transport speed of the pollutants in the study area were analyzed. This work not only successfully found the location of CCL4-pollution sources, but also helped the local government to analyze the year of pollutant release and recognize the transport pattern of CCL4 in aquifers.

Heavy metals in coastal soils and sediments of the ponds in Samara

The total contents of Mn, Cr, Ni, Cu, Zn, Pb and Cd in foreshore soils and bottom sediments of 20 ponds have been investigated for the first time in Samara by the method of spectrometry with inductively coupled plasma. It is shown that polymetallic pollution of coastal soils and bottom sediments of 16 ponds out of 20 considered is acceptable; 3 ponds, located in the 13th microdistrict (small pond) and on the Solnechnaya street (large and small ponds), are characterized by moderately hazardous pollution with heavy metals; 1 pond, located in the area of the former Hippodrome, has a high level of pollution of coastal soils. Cu, Zn and Pb should be considered to be the main elements that significantly affected the ecological state of coastal soils and bottom sediments of the studied ponds. Their content in selected samples ranged: from 0,3 to 20,3 for Cu, from 0,2 to 14,9 units for Zn, from 0,2 to 25,2 units of background concentrations to Pb. The analysis of heavy metals average levels in coastal soils and bottom sediments of Samara ponds showed, that bottom sediments were enriched with all analyzed metals except Mn in comparison with coastal soils, whereas Mn was accumulated to upper levels in coastal soils. The location of water bodies in various parts of the urban area relief caused differences between the levels of heavy metals accumulation. For instance, the coastal soils of the ponds located on the watershed between the Saratov reservoir and the Samara River accumulated heavy metals more actively than the coastal soils of the ponds on the Volga slope. The accumulation of heavy metals in bottom sediments on the watershed was more active for Mn, Cr, Zn and Cd whereas in the ponds on the Volga slope it was shown for Ni, Cu and Pb.

Spectral Similarity: Full-Wavelength Range Calibration of Circular Dichroism Spectroscopy.

Circular dichroism (CD) measurements help characterize optically active molecules and higher-order biomolecular structures. The harmonization of interlaboratory CD measurements requires minimizing measurement uncertainties and determinate errors. Most CD measurements utilize a single-wavelength intensity measurement at a spectral peak to calibrate the intensities of the ultraviolet wavelength range. However, such a single-wavelength calibration is inherently less precise than using the CD instrument's spectrum over the entire measured spectral range. A more thorough and informative calibration can be achieved by remapping the spectrum into what we call a spectral similarity plot. This process allows a straightforward, quantitative evaluation of the shape congruence between two spectra over the full spectral range. While preliminary analyses suggest spectral similarity plots can be utilized with a variety of different spectrometry methods, here we illustrate the process applied to circular dichroism. Spectral similarity plots are highly sensitive to deviations due to differences in concentration, pathlength, source and detector properties, circular polarization balance, as well as wavelength nonlinearities and shifts. Deviations in these properties can be quantitated by a linear least squares fit of the remapped data. The remapping enables protocols to correct spectra toward congruence between two spectra. The spectra similarity comparison provides an objective, unambiguous test of the CD instrument quality when, for example, compared to a carefully calibrated system as shown in the examples described in the text.

Leaching from a 3D-printed aligner resin.

To quantitatively assess the degree of conversion and the water-leaching targeted compound from 3D-printed aligners. 3D-printed aligners were made of photopolymerized resin (Tera Harz TC85A). The molecular structure and degree of conversion of the set resin were investigated by ATR-FTIR spectroscopy (n = 5). The aligners (n = 10) were immersed in double distilled water for 1 week at 37°C and the eluents were analysed using liquid chromatography/mass spectrometry methods (LC-ESI-MS/MS for urethane dimethacrylate [UDMA] and LC-APCI-MS/MS for bispenol-A [BPA]). The resin was composed of aliphatic vinyl ester-urethane monomers, with acrylate and/or methacrylate functionalization. The degree of conversion was estimated as to 83%. There was no detection of BPA in any of the assessed samples (0.25 µg/l). Quantifiable amounts of UDMA were detected in all the exposed samples, ranging from 29 to 96 µg/l. Although efficiently polymerized and BPA free, the great variability in the amount of UDMA monomer leached from the examined samples may raise concerns on potential health hazards after repeated intraoral exposure, which is indicated for this class of materials.

Assessment of Polyacrylamide Concentration in Construction Stormwater Runoff Using an ASTM D6459 Rainfall Simulator

Polyacrylamide (PAM) is a polymer used in construction stormwater management as both an erosion and sediment control measure. PAM is considered one of the environmentally safest polymers on the market, however overapplication concerns dictate that large quantities in runoff be avoided. For slope erosion applications, ensuring proper concentration requires methods for testing residual concentrations. This research investigated residual concentrations of PAM when dry-applied at a rate of 25 lb/acre (28 kg/ha) for slope stabilization and subjected to 1-h of simulated rainfall following ASTM D6459-19 protocols at three 20-min successive 2-, 4-, and 6-in./h (5-, 10-, and 15-cm/h) intensities. Residual concentrations were determined by centrifuging runoff samples to remove soil and reading absorbance from an ultraviolet-visible spectrometer, comparing values to those at known concentrations. Concentrations in collected runoff samples were found to surpass values found in previous research and in other PAM applications, especially during first flush, and were high enough to affect water viscosity. An alternative application method is presented that may mitigate PAM runoff concentration. The spectrometry method was also used to highlight the possibility that polymers used in hydromulches may also deposit excess concentrations in stormwater runoff, and that formal residual testing of such products is warranted. The processes used for this study demonstrated how discharge may be monitored and regulated to minimize undesirable runoff conditions from construction sites and underscore the importance of appropriate design and implementation when using additives for erosion control.

Control quality measurements of alpha and beta counter with low back-ground ALBA 2000 v.2.5.6.

The article provides a systematic approach to quality control of measurements of total alpha-and beta-activity using a counter with a low background ALPHA / BETA COUNTING SYSTEM ALBA (mod. ALBA / LLAB) and software ALBA 2000 v.2.5.6. The purpose is to determine the compliance of these objects with the requirements of regulatory documentation. The spectrometry method is based on the physical concentration of radionuclides from the sample volume, measuring the rate of alpha, and beta radiation of the obtained dry residue of the sample, comparing the sample count rate with calibration values of activity, and calculating the total alpha, beta activity of the sample. The primary means of testing is a counter with a low background ALPHA / BETA COUNTING SYSTEM ALBA 200, the lower limit of measurements of the alpha activity, which is 0.02 Bq/l, and beta activity of 0.1 Bq/l, the relative random uncertainty of the measurement result is 60 % with a confidence level P = 0.95. The efficiency of registration on the alpha channel of 43 %, background on the alpha channel of 0,11 imp./min, for a measurement time of 60,000 s, the efficiency of registration on the beta channel of 30 %, background on the beta channel of 1,9 imp./min, for measurement time 60000 s. As a comparison sample for calculating total alpha activity, a sample with alpha radiation, 241Am (geometry 2π), is used. To calculate the total beta activity, a sample of beta-emitter of potassium sulfate with radionuclide is used at 40K (geometry 2π). The weight of the counting sample ranges from 200 to 1000 mg. The activity values are calculated automatically, using the software ALBA 2000, v.2.5.6. Measurement of the total activity of radionuclides in counting samples using the method should be performed only in calibrated geometries. At the same time, the safety requirements, personnel qualifications, and test conditions must be met. Quality control of measurements in the alpha, beta counter ALBA-2000 v.2.5.6. It is carried out in qualitative and quantitative ways.

Association between forage mycotoxins and liver disease in horses.

BackgroundOutbreaks of liver disease in horses are common but the etiology of most remains unknown. Forage mycotoxins have been suspected to be a cause.ObjectivesTo examine the association between outbreaks of liver disease and the presence of mycotoxins in forage stored on the same premises.AnimalsPremises were identified where ≥4 horses were contemporaneously affected by liver disease, and a control group was formed from premises where ≥4 horses had been examined and found to have no evidence of liver disease.MethodsForage was collected from 29 case and 12 control premises. The forage was analyzed for mycotoxin content using a liquid chromatography/mass spectrometry method, targeting 54 mycotoxins. The presence and distribution of mycotoxins between case and control samples was compared.ResultsMycotoxins were found in 23/29 (79%) case samples and 10/12 (83%) control samples (P > .99; relative risk, 0.93; 95% confidence interval [CI], 0.64‐1.75). Median (interquartile range [IQR]) total mycotoxin concentration was similar in case and control samples (85.8 μg/kg [1.6‐268] vs. 315 μg/kg [6.3‐860]; P = .16). Ten mycotoxins were found exclusively in case premises comprising fumonisin B1, 15‐acetyldeoxynivalenol, deoxynivalenol, zearalenone, aflatoxins B1 and G1, methylergonovine, nivalenol, verruculogen, and wortmannin. The median (IQR) concentration of fumonisin B1 was significantly higher in case versus control samples (0 μg/kg [0‐81.7] vs. 0 μg/kg [0‐0]; P = .04).Conclusions and Clinical ImportanceSeveral mycotoxins with known hepatotoxic potential were found, alone or in combination, exclusively at case premises, consistent with the hypothesis that forage‐associated mycotoxicosis may be a cause of outbreaks of liver disease in horses in the United Kingdom.

Simultaneously Determining Seven Second-Line Anti-TB Drugs by UHPLC- MS: Application for TDM in HIV-TB Patients

Background: To optimize therapy for patients with human immunodeficiency virus-tuberculosis (HIV-TB) coinfection, we developed an ultra-high-performance liquid chromatography/- tandem mass spectrometry (UHPLC-MS) method to monitor seven second-line anti-tuberculosis drugs. Methods: Blood samples (n = 70) were collected from 35 patients with HIV-TB coinfection; the plasma sample was protein-precipitated and diluted with a solution containing heptafluorobutyric acid. The plasma concentrations of rifabutin (RBT), clofazimine (CLO), moxifloxacin (MFX), prothionamide (PTH), levofloxacin (LFX), amikacin (AMK), and para-aminosalicylic acid (PAS) were detected by UHPLC-MS/MS method. Results: In these 70 samples, the mean concentrations of RBT, CLO, MFX, PTH, LFX, and AMK were 173.8 (10.0–550.0), 61.1 (54.4–67.7), 646.6 (25.0–2480.0), 120.5 (50.0–597.0), 1565.9 (100.0–3480.0), and 10753.0 (400.0–76 700.0) μg/L, respectively. Only one sample was detected to have PAS with a concentration less than the lower limit of quantification. Most of the drug concentrations detected in these patients were lower than the targeted concentrations in TB patients. Conclusion: We created a simple UHPLC-MS method for simultaneously quantifying anti-TB drugs. The plasma concentrations in HIV-TB co-infected patients were lower than the targeted concentrations. It is important to monitor anti-TB drugs in the future. This method will facilitate the monitoring of anti-TB drugs in the future.