Detection of polycyclic aromatic hydrocarbon levels in milk collected near potential contamination sources

Polycyclic aromatic hydrocarbons (PAHs), mainly formed by incomplete anthropogenic organic matter combustion, are ubiquitous in the environment. To assess milk PAH contamination sources, milk samples were collected from the tank milk at farms located near potential contaminating emission sources such as cementworks, steelworks, and motorways. PAH analyses were carried out by gas chromatography coupled to mass spectrometry. Eight PAHs were identified in milk: naphthalene, acenaphthylene, acenaphthene, fluorene, anthracene, fluoranthene, pyrene, and benzo[a]anthracene. For all potential contaminating sources, these eight PAHs were detected with similar profiles and at low concentrations except for fluorene and naphthalene, for which source-molecule interaction is pointed out.     

ToF-SIMS characterization of thermal modifications of bixin from Bixa orellana fruit

Bixa orellana fruit extracts were studied by time-of-flight secondary ion mass spectrometry (ToF-SIMS). The intensity of the peak at m/z 396, assigned to the bixin molecular ion plus two hydrogen atoms (C25H(32)O(4+), decreased as the extract was heated and nearly disappeared with heating above 150 degrees C. Simultaneously, the formation of dimers at m/z 790, 804, and 818 was observed. The ToF-SIMS spectrum is characterized by a large amount of peaks generated by the principal ions and their multiple fragmentation patterns. To extract maximum information from the data set, multivariate statistical analysis was applied. Principal component analysis revealed important structural changes of the bixin molecule upon heating at different temperatures. This information can be used by the food industry as by controlling the temperature of the heating process the red/yellow balance of this colorant can be tuned.     

The Importance of Precedent Hydro-climatological Conditions for the Mass Transfer of Pollutants in Separated Sewer Systems and Corresponding Tributaries During Storm Events

Runoff events were analysed in separated sewer systems in the town of Luxembourg. The relationships between Event Mean Concentrations of different pollutants and runoff patterns were evaluated. In addition, the inter-storm and intra-storm variability of the material transport were determined. Primarily, the variations in pollutant concentrations and loads are determined by the antecedent weather conditions. The presence of illicit sanitary inputs in one of the sewers produced a significant first flush effect as well as higher Event Mean Concentrations for pollutants. Furthermore, near the town of Trier 40 storms were analyzed in a small natural basin mainly influenced by runoff from a separated sewer system. Natural and artificial storm events were investigated in order to estimate the relationship between the pollutant sources in the channel and from the separated sewer system. Just like in the canalization of Luxembourg City the pollutant dynamics during natural storms are strongly influenced by pre-event hydrological conditions. The artificial storms behave differently. Despite little pre-rain, the maximum concentrations of toxic substances are comparatively low. A resuspension of sediment only occurs in the natural channel system, without the introduction of fines from the sewer system.     

Milk fever and alert downer cows: does hypophosphatemia affect the treatment response?

The purpose of this prospective cohort study was to identify factors that place a dairy cow with uncomplicated milk fever (MF) at significant risk of becoming an alert downer cow (ADC) and to verify if these factors could be used to predict treatment outcome. Recumbent MF cows were examined before treatment and 52 were excluded due to complications. In all, histories and pretreatment serum samples were taken and the serum of 86 cows was analyzed for electrolyte levels (calcium, phosphorus, magnesium, and potassium). In total, 36 of the 86 samples were from ADCs and 50 from animals that responded to MF treatment (MFT). A binary-two-factor logistic model determined that a MF cow with a phosphorus pretreatment level of > or = 0.9 mmol/L was 12 times more likely not to become an ADC than one with a phosphorus level < 0.9 mmol/L (CI: 6.3,23.1). Also, a binary multivariable logistic regression analysis showed that a MF cow with a pretreatment calcium level > or = 1.7 mmol/L was 14 times more likely to become an ADC than one with a serum level < 1.7 mmol/L (CI: 2.0,98). Age and the other serum electrolytes were not statistically significant risk factors at the 0.05 level. The rigorous pretreatment examination and stringent adherence to protocol reduced ADC misclassification and fostered the strong association between single factor serum phosphorus levels and ADCs. By using a cutoff level of serum phosphorus at > or = 0.9 mmol/L, a practitioner could correctly predict that 95% of the MFs would not become ADCs and, therefore, this level would be a useful pretreatment predictor.     

SENSITIVITY AND SPECIFICITY OF RADIOGRAPHIC DETECTION OF CANINE ELBOW INCONGRUENCE IN AN IN VITRO MODEL

Canine elbow incongruence is believed to be the consequence of underdevelopment of the radius. The purpose of this study is to determine the sensitivity and specificity of radiography to detect elbow incongruence in an in vitro model and to assess the optimal elbow angle and radiographic beam position. Five normal cadaveric canine left forelimbs were used. A four-pin, type 1 external fixator with a linear motor side bar was fixed to the cranial part of the radius of each limb and a 1 cm segment of bone was removed from the mid-diaphysis to allow radial shortening. Each elbow was subjected to the same protocol. They were radiographed at two different angles (90 degrees and 135 degrees) of flexion, with 10 different radiographic beam positions (centered on the humeral condyle, 3 cm cranial, 3 cm caudal, 3 cm distal, 3 cm proximal, 3 cm cranio-proximal, 3 cm cranio-distal, 3 cm caudo-proximal, 3 cm caudo-distal and on the shoulder joint) and at four different level of radial shortening (0, 1, 2 and 3 mm). In addition, a radiographic view centered on the elbows flexed at 135 degrees was made after simulating weight bearing. The acquired digital images were independently evaluated by three evaluators unaware of the elbows status. The elbows were judged normal, incongruent or borderline based on specific criteria. The sensitivity for detection of elbow incongruence at and beyond 2 mm was excellent at 90 degrees (median = 100% for all views) and good at 135 degrees (median = 80%) of flexion with no difference between examiners. The sensitivity at 1 mm of incongruence was unchanged at 135 degrees but was reduced at 90 degrees of flexion (median = 60%) with a significant difference between the evaluators. The specificity was significantly different between the evaluators and ranged from 70% to 90% at 90 degrees of flexion and from 50% to 80% at 135 degrees. The lowest specificities at 90 degrees were obtained with the proximal displacements of the X-ray beam. Simulating weight bearing significantly decreased the sensitivity at 1 mm (from 80% to 50%) and 3 mm (from 100% to 80%) of incongruence and slightly increased the specificity (from 55% to 65%). Radiography is a sensitive and specific test to detect moderate-to-severe radio-ulnar incongruence (2 mm and over) if the elbow is flexed at a 90 degrees angle regardless of the radiographic beam position. Finally, canine elbow incongruence appeared reduced after an in vitro weight-bearing simulation.     

Odor Modification in Salmon Hydrolysates Using the Maillard Reaction

The aim of this work was to study the effect of adding sugar during proteolysis to promote the Maillard reaction and mask the initial fish odor and off-flavors generated. An experimental design, based on the Doehlert plan, was used to study the influence of hydrolysis conditions (time, temperature, sugar, and antioxidant addition) on the odor characteristics of hydrolysates, soluble protein levels, and amino acid content. Results showed that the lowest level of sugar (10 g of D-xylose added to 1 kg of by-products) was enough to develop a grilled odor in hydrolysates. In the hydrolysis conditions used—i.e., enzyme inactivation at 95°C for 30 min—hydrolysis temperature had no effect on grilled odor production but significantly affected the soluble protein fraction, as did hydrolysis time. Soluble protein content and essential amino acid content increased with the enzymatic reaction but were not modified by adding sugar. Hydrolysis conditions that promote Maillard reactions while keeping a nutritional balance have been identified.