To disinfect or not to disinfect that is the question - Procedure when drawing blood for alcohol measurements in Denmark.

Swabbing with ethanol to disinfect the skin before venipuncture does not bias measurements of blood ethanol, as previously suspected. International evidence-based theory may not always be successfully integrated into local practices, where old customs may remain. So how are the local protocols for swabbing in practice - if they even do swab? Not disinfecting may risk patient safety. We aim to put a focus on the venipuncture disinfection procedure in practice when measuring blood alcohol for clinical matters and if their procedure refers to a guideline. Specialized biomedical laboratory scientists (BLS) are typically responsible for the phlebotomy procedure in Denmark, thus questionnaires were sent to the relevant BLS in 2020 to map disinfection procedures in all Danish hospitals and affiliated blood draw clinics (n = 58). The response rate was 93% (54/58). We observed an inter-laboratory dissimilarity in swabbing procedures, when measuring blood alcohol: A quarter did not use any disinfectant (26%), while the remaining disinfected with ethanol 55%, isopropanol 13%, and 6% with ethanol/chlorhexidine. Of the five Danish regions, three had a regional guideline (3/5), otherwise the swabbing protocol was locally based. There was a regional difference in disinfecting or not (Chi2 p < 0,0001). Danish protocols do not always parallel international literature and international guidelines. Not applying disinfectant may jeopardize patient safety. Laboratories are encouraged to work with evidence-based practice or follow newest standardized international guidelines.

Phosphorus recovery by ion exchange in a solid carbonate: modeling of the process.

Phosphorus (P) is a nutrient for plant growth but also a pollutant in water bodies causing eutrophication. The source of P is mainly human and animal wastewater and runoffs from different land uses. The objective of the present study is to evaluate P removal and recovery processes by ion exchange (IE) with solid carbonate (SC) in biodigestor-treated swine effluent (BTSE) using hydrogeochemical modeling. For this, BTSE compositions were obtained by literature review. A synthetized and characterized SC was used and the ion exchange site concentration ([SC-IE]) and the IE constants (Kie) were obtained experimentally and applied to model P and major anion removal and recovery processes. P recovery was evaluated for different BTSE compositions and several concentrations of SC, dissolved P (HPO42-), competing anions such as SO42-, and CO32-. The simulations suggest that a [SC-IE]:[HPO4] of 1.4 molar ratio would allow the recovery of 90% of HPO4 in BTSE, and at average alkalinity concentrations in BTSE, CO32- would compete with HPO4 for the SC-IE. The P recovery by the SC-IE process was compared with two other methods commonly used in P removal from BTSE: removal with aluminum sulfate and precipitation of struvite as a function of pH. The results suggest that SC-IE is the most efficient method in the pH range of BTSE. Besides, HPO42- was readily recovered as inorganic P that may be reused in agriculture and industrial processes.

Effect of mono and divalent salts on the conformation and composition of a humic acid and on atrazine adsorption.

We investigated the effects of sodium and calcium chlorides on the conformation and composition of a purified Aldrich humic acid (PAHA), as well as on the adsorption of atrazine. The PAHA was treated with 1, 10, and 100 mM NaCl, CaCl2, or a mixture of NaCl and CaCl2 (molar ratio 5:1) at pH 7.5 and 8.5. The conformation of treated PAHA was characterized by atomic force microscopy (AFM) and transmission electron microscopy (TEM) and spectral changes of functional groups of PAHA by Fourier transform infrared spectroscopy (FTIR). AFM and TEM images showed an increase in the aggregation of the PAHA as salinity increased. FTIR spectra revealed that changes in the aggregation of the PAHA were principally due to the formation of bridged interactions between calcium and carboxylate groups in the PAHA. The adsorption of atrazine on > 0.45 µm PAHA decreased as salt concentrations and pH increased. This reduction of atrazine adsorption was explained by the decrease in available adsorption sites due to agglomeration of PAHA.

Nutrient loads in the river mouth of the Río Verde basin in Jalisco, Mexico: how to prevent eutrophication in the future reservoir?

Since nutrients are emitted and mobilized in river basins, causing eutrophication of water bodies, it is important to reduce such emissions and subsequent nutrient loads. Due to processes of attenuation, nutrient loads are reduced during their mobilization in river basins. At the mouth of the Río Verde basin in western Mexico, the El Purgatorio dam is being constructed to supply water to the metropolitan area of the second most populated city in the country, Guadalajara. To analyze situations that allow protecting this future dam from eutrophication, nutrient loads in the mouth of the river basin were determined and their reduction scenarios evaluated by using the NEWS2 (Nutrient Export from Watersheds) model. For this, a nutrient emissions inventory was established and used to model nutrient loads, and modeling results were compared to an analysis of water quality data from two different monitoring sites located on the river. The results suggest that 96% of nitrogen and 99% of phosphorus emissions are attenuated in the watershed. Nutrient loads reaching the mouth of the river basin come mainly from wastewater discharges, followed by livestock activities and different land uses, and loads are higher as emissions are located closer to the mouth of the river basin. To achieve and maintain mesotrophic state of water in the future dam, different nutrient emission reduction scenarios were evaluated. According to these results, the reduction of 90% of the phosphorus loads in wastewater emissions or 75% of the phosphorus loads in wastewater emissions and at least 50% in emissions from livestock activities in the river basin are required.

Conductometric measurement of the changes in humic substances caused by ozone oxidation.

Humic substances (HS), a broad category of organic compounds and a major constituent of soil, are responsible for serious problems during water purification processes. In particular, HS react with chlorine during disinfection processes to produce a variety of organochlorine compounds such as trihalomethanes (THMs), which are potentially carcinogenic to humans. The use of ozone as a disinfection method represents a potential solution to this problem; however, HS that are not completely oxidized may form by-products more reactive than the original molecules. The structural changes of HS during oxidation with ozone were evaluated through a replicated 2(2) design, where concentrations of 5 and 30 mg/L of two commercial HS (Aldrich and Fluka) were ozonized over different time intervals (0, 10, and 20 min). The ozone-treated HS were titrated with acid and base solutions, and the shifts of the slopes were then analyzed and finally related to the ionic alterations of the HS. The Aldrich HS (AHS) showed only protonated functional groups; the Fluka HS (FHS) showed only ionized groups; and in both cases, the amount of functional groups increased with increasing ozonation. For AHS and FHA, respectively, the maximum ozone exposure time (20 min) and the highest concentration of HS (30 mg/L) produced the greatest reductions in total organic carbon (TOC) (39 and 34 %), UV254 (50 and 60.8 %), and color (16.4 and 19.6 %). As for aromaticity, AHS showed removals of 39.6 % (from a starting concentration of 5 mg/L) and 17.2 % (from a starting concentration of 30 mg/L). FHS showed the opposite effect, with removals of 33.3 % (starting at 5 mg/L) and 40.1 % (starting at 30 mg/L). In this study, the structural changes of HS submitted to ozonation were inferred in a relatively quick and easy way by using a conductometric titration, thus demonstrating the applicability of the technique.

Internal phosphorus load in a Mexican reservoir: forecast and validation.

To determine the internal phosphorus load (IPL) as a function of redox potential (Eh) in a Mexican reservoir, the results from a phosphorus (P) release experiment were extrapolated to temporal and spatial variations of Eh in sediments, and an IPL-Eh of 24.2 ± 2.5 t/yr was obtained. This result is compared with the P mass balance (MB) in the reservoir, where the IPL-MB is determined as the difference between P inputs to the reservoir and the outputs. Inputs of P are the sum of the external P load from the hydrological basin, the IPL, and P in atmospheric precipitation; outputs of P are the sum of sedimented P, and the removal of P in water and biomass, and the resulting IPL-MB, is 26.4 ± 4.9 t/yr. In addition, P concentrations in sediment cores (SCs) are analyzed, and the historical release of P from sediments determined, resulting in an IPL-SC of 23.5 ± 1.4 t/yr. The different IPL results are similar, as average values are within the standard deviation of IPL-MB. It is concluded that analysis of the variations in Eh in sediments allows determination of the reservoir's IPL. Six-weekly IPL-Eh and IPL-MB values are analyzed, and it can be seen that IPL occurs mainly during the period from May to August, when the water column is thermally stratified.

A chi-square goodness-of-fit test for autoregressive logistic regression models with applications to patient screening.

We propose a chi-square goodness-of-fit test for autoregressive logistic regression models. General guidelines for a two-dimensional binning strategy are provided, which make use of two types of maximum likelihood parameter estimates. For smaller sample sizes, a bootstrap p-value procedure is discussed. Simulation studies indicate that the test procedure satisfactorily approximates the correct size and has good power for detecting model misspecification. In particular, the test is very good at detecting the need for an additional lag. An application to a dataset relating to screening patients for late-onset Alzheimer's disease is provided.

Observations of mercury wet deposition in Mexico.

We provide a longer-term record of Hg wet deposition at two tropical latitude monitoring sites in Mexico, selected to provide regionally representative data. Weekly wet deposition samples were collected over 2 years, from September 2003 to November 2005. Based on this data set, we discuss the magnitude and seasonal variation of Hg in wet deposition and compare the results to other measurement sites and to several model estimates. With precipitation-weighted mean (PWM) concentrations of 8.2 and 7.9 ng L(-1), respectively, during the sampling period from Sep 30 2003 to Oct 11 2005, and median weekly concentrations of 9.4 ± 1 ng L(-1) for both sites, the wet Hg concentrations and deposition at HD01 were much lower than those observed at the US Gulf Coast MDN sites while the wet Hg deposition at OA02 was much lower than most MDN sites, but somewhat similar to US MDN sites along the Pacific Coast. Based on the limited available data, we conclude that the approximately 30 % higher average precipitation at HD01 and roughly equal PWM concentrations lead to the higher deposition at HD01 versus OA02. We believe that these observations may offer scientists and modelers additional understanding of the depositional fluxes in the lower latitudes of North America.

Development and validation of an abridged measure of organizational justice.

In this 3-Study article, the authors present an abridged version of Colquitt's (2001) 20-item measure of organizational justice. In Study 1, using a sample of 278 undergraduate students, they applied a systematic scale-reduction technique to determine which items should remain in the abridged scale. In Study 2 and 3, using two separate field samples (N = 173, N = 517; respectively) they provide construct, convergent, and discriminant validity evidence in support of the abridged scale. Their results provide evidence that the abridged version of Colquitt's measure maintains the psychometric quality of the original full scale and, therefore, can be used in its place.

In vivo detection of cortical optical changes associated with seizure activity with optical coherence tomography.

The most common technology for seizure detection is with electroencephalography (EEG), which has low spatial resolution and minimal depth discrimination. Optical techniques using near-infrared (NIR) light have been used to improve upon EEG technology and previous research has suggested that optical changes, specifically changes in near-infrared optical scattering, may precede EEG seizure onset in in vivo models. Optical coherence tomography (OCT) is a high resolution, minimally invasive imaging technique, which can produce depth resolved cross-sectional images. In this study, OCT was used to detect changes in optical properties of cortical tissue in vivo in mice before and during the induction of generalized seizure activity. We demonstrated that a significant decrease (P < 0.001) in backscattered intensity during seizure progression can be detected before the onset of observable manifestations of generalized (stage-5) seizures. These results indicate the feasibility of minimally-invasive optical detection of seizures with OCT.

Mild cognitive impairment: prodromal Alzheimer's disease or something else?

The majority of mild cognitive impairment (MCI) studies use baseline and one follow-up measurement to determine the clinical course of the disorder. This report of MCI clinical course is based on the a statistical evaluation of multiple neurocognitive tests over a 60 month period in elderly normal and MCI cohorts. The data includes serial informant-based measures (Clinical Dementia Rating [CDR]) and a comprehensive battery of neuropsychological tests analyzed by two different regression methods. Twenty-nine elderly participants entered the study as neurocognitively normal; 26 remained normal, 2 progressed to MCI, and 1 progressed to dementia. Eighty-three participants entered the study as multiple domain MCI cases; 10 became normal, 46 remained MCI, and 27 progressed to dementia. Three of the 27 demented died with full necropsies performed (one case was progressive supranuclear palsy and two confirmed Alzheimer's disease with severe cerebral amyloid angiopathy (CAA)). Without serial measures, 1 in 8 MCI could be misclassified as "stable MCI" despite reverting to normal. The stable MCI cohorts did not benefit from practice effects though the normal subjects did. Applying Classification and Regression Tree (CART) analysis enabled prediction of the endpoint status of participants from baseline values with 78.6% accuracy. The fluctuating cognitive status of the multiple domain MCI cases implies a remitting pathologic process with elements of recovery consistent with a progressive microvasculopathy such as CAA.

Scenarios of metal concentrations in the Arcediano Dam (State of Jalisco, Mexico).

The city of Guadalajara, Jalisco, Mexico has 4.1 million inhabitants and a serious deficit in water supply. Once constructed, the Arcediano Dam will catch waters from the Verde and Santiago rivers, and after treatment will provide water to the city. The present study was undertaken to formulate scenarios and estimate risks of polluting the water that will be collected in the dam from the release of contaminants accumulated in sediments. Desorption of metals from sediments was estimated through sampling of water and sediments, chemical analyses of the environmental samples, and numerical modeling of the water-sediment interactions. Water quality generally increased as the river flowed downstream from the El Salto sampling station to the site where the Arcediano Dam will be constructed. Aluminum exceeded the Mexican Criterion for Drinking Water Supply (MCDWS), at all sampling stations, whereas iron and manganese surpassed the criteria at some stations. Trace metals were below their respective criteria. For sediment samples in the river, chrome, copper and zinc exceeded the Canadian Interim Sediment Quality Guidelines (ISQG), whereas manganese and nickel exceeded the probable effect level (PEL). Other metals were below these limits. With exception of the El Salto sampling station, metals were mostly enriched in iron-containing sediments, followed by aluminum-containing clays and, to a lesser extent, by manganese oxides. Therefore, the interaction of metals with iron oxides was considered as the controlling adsorption mechanism. Simulations to estimate risks of water contamination by desorption of metals from sediments indicate that manganese and nickel may reach concentrations higher than the CDWS. In some cases, dissolved concentrations of lead and chrome may be higher than the respective CDWS, especially under conditions of high accumulation of sediments in the dam. Arsenic, copper and mercury concentrations did not exceed the CDWS under the simulated conditions.

Mineralization of atrazine in agricultural soil: inhibition by nitrogen.

Microbial mineralization of atrazine was characterized in soils and liquid media in the presence of nitrogen fertilizer concentrations representing typical field applications. The mineralization of atrazine in soils varied between 6 and 99% after 18 d of incubation. Half-lives of between 0.99 and more than 18 d were obtained. Mineralization kinetics and degree are related by a reciprocal trend to concentrations of available nitrogen in the soil. In liquid media, half-lives were calculated as 0.12 d in the absence of fertilizer nitrogen and as 79 d in the presence of 1,000 mg/L of KNO3-N. Only 20% of atrazine was mineralized after 18 d of incubation in the presence of this concentration of KNO3-N, whereas greater than 90% mineralization occurred after 2 d of incubation in liquid medium without KNO3-N. The results demonstrate that the mineralization of atrazine is inhibited even at fertilizer nitrogen levels lower than typical field applications. Inhibition in soil is lower than that in liquid medium, possibly because of the higher complexity of the soil system. This may explain why atrazine that infiltrates to the groundwater is persistent. The microbial consortium of the soils was characterized, and seven species were identified. The degrading capacity of these species suggests that only three species are involved in the degradation of atrazine.

Novel pyrazine metabolites found in polymyxin biosynthesis by Paenibacillus polymyxa.

A complex mixture of methyl-branched alkyl-substituted pyrazines was found in the growth medium of the polymyxin-producing bacterium Paenibacillus polymyxa, and of these, seven are new natural compounds. A total of 19 pyrazine metabolites were identified. The dominant metabolite was 2,5-diisopropylpyrazine as identified using a combination of high-resolution mass spectrometry, (1)H- and (13)C-nuclear magnetic resonance, gas chromatography-mass spectrometry as well as co-elution with an authentic standard. Its biosynthesis was correlated with growth and production was strongly stimulated by valine supplementation. The other pyrazine metabolites, all related pyrazines with either one, two or three alkyl substituents, were identified by means of their mass spectral data and/or co-elution with authentic standards.

Expression of recombinant Pseudomonas stutzeri di-heme cytochrome c4 by high-cell-density fed-batch cultivation of Pseudomonas putida.

The gene of the di-heme protein cytochrome c(4) from Pseudomonas stutzeri was expressed in Pseudomonas putida. High-yield expression of the protein was achieved by high-cell-density fed-batch cultivation using an exponential glucose feeding strategy. The recombinant cytochrome c(4) protein was purified to apparent homogeneity and analyzed by electronic absorption spectroscopy, nanoflow electrospray ionization time-of-flight mass spectrometry, and electrochemistry. Cyclic voltammograms and UV-vis electronic absorption spectra were indistinguishable from the equivalent data of native P. stutzeri cytochrome c(4). Furthermore, the calculated and experimentally determined molecular masses of recombinant cytochrome c(4) were identical. Biochemical characterization of both wild-type and mutant derivatives of the protein will be greatly enhanced and facilitated by the described high-yield fermentation and rapid isolation procedure.