Selenium and vitamin E and incidence of retained placenta in parturient dairy cows. II. Prevention in commercial herds with prepartum treatment

In a series of field experiments in Ohio involving 193 parturient cows of the Holstein and Guernsey breeds, the prophylactic efficacy of selenium and vitamin E was tested under field conditions. Herds initially were chosen because of a chronic problem with retained placenta which could not be related to a known etiological factor. Each herd was divided into three groups. Group A received an injection of 50 mg of sodium selenite 40 days prepartum and 680 units of alpha tocopherol acetate followed by the same treatment 20 days prepartum. Group B received a single injection of 50 mg of sodium selenite 20 days prepartum, and 680 IU of vitamin E. Group C served as the control. Incidence of retained placenta was reduced from a mean of 51.2% in control cows to 8.8% for animals injected with selenium and vitamin E. No differences in efficacy were between Group A and B, and it appears that the single 20 day prepartum injection of 50 mg of sodium selenite and 680 IU of alpha tocopherol acetate is an effective prophylactic for prevention of retained placenta.     

In vitro screening of probiotics and synbiotics according to anti-inflammatory and anti-proliferative effects

There is emerging evidence of the efficiency of probiotic, prebiotic and synbiotic treatments in inflammatory bowel diseases (IBDs) and one of their long-term complications, colorectal cancer (CRC). In this study, various strains of probiotic lactic acid bacteria, prebiotic glucooligosaccharides (GOS) or a synbiotic combination of the two were screened for anti-inflammatory and anti-proliferative effects in different in vitro models in the context of such diseases. To mimic IBD response to Gram negative bacteria, HT-29 cells were sensitised to inflammatory response to lipopolysaccharide (LPS) by IFNγ which increased expression of TLR4, the LPS biosensor, and were then treated by probiotics, prebiotics and synbiotics. Secreted IL-8 and activated NF-κB were monitored as inflammation biomarkers. A selection of active strains were then subjected to a second inflammatory cell culture model consisting of inflammatory activated transgenic Caco-2 cells transfected by a reporter gene under the control of NF-κB inducible promoter. Quantification of reporter gene expression allowed us to demonstrate some probiotic inhibitory properties or to confirm such characteristics in two different models. Proliferation of cancerous HT-29 cells was monitored by XTT assay. Only three probiotic strains induced a proliferation decrease, but with a lack of reproducibility. Binary or ternary probiotic associations, complemented or not by prebiotic GOS, significantly decreased proliferation, especially with a synbiotic association of Bifidobacterium breve, Lactococcus lactis and oligoalternan, a GOS. This combination was selected for the following experiments. We showed the involvement of both bacterial and carbohydrate compounds of this synbiotic in the observed effect by dose range tests. We demonstrated that this decrease in proliferation may be due to an induction of a differentiated phenotype, as shown by the up-regulation of intestinal alkaline phosphatase, a biomarker of differentiation, monitored by real-time RT-PCR in HT-29 cells treated by the selected synbiotics. Thus, this study demonstrates the ability of probiotics to exert anti-inflammatory effects and shows some anti-proliferative characteristics for a specific synbiotics. These products should be further evaluated in animal models to confirm the in vitro results.     

Experimental investigation of the influence of the FSW plunge processing parameters on the maximum generated force and torque

A statistical design of experiments (DOE) approach was used to determine if specific build orientation parameters impacted mechanical strength of stereolithography (SL) fabricated parts. A single platform (25.4 × 25.4-cm cross-section) on the 3D Systems Viper si2 SL machine was designed to hold 18 ASTM D-638 type I samples manufactured in different orientations. The DOE tested three factors: axis, layout, and position. Samples were fabricated parallel with the x-axis or y-axis, or 45° to both axes (called axes 1, 2, and 3, respectively). For each axis, samples were fabricated either flat or on an edge relative to the x–y plane (called layouts 1 and 2, respectively). Three samples were manufactured for each layout and axis combination, and the samples were labeled as positions 1, 2, or 3 depending on the distance from the center of the platform with position 1 being the closest to the center. The results from the statistical analyses showed that axis and position had no significant effect on ultimate tensile stress (UTS) or modulus of elasticity in tension (E). However, layout (or whether a sample was built flat or on an edge) was shown to have a statistically significant effect on UTS and E (at a 95% level of confidence). The differences between average UTS and E for each of the samples built flat and on an edge were ~3.53% (43.2 versus 44.8 MPa) and ~4.59% (763.9 versus 800.7 MPa), respectively. Because of the relatively small differences in means for UTS and E, the statistical differences between layout most likely would not have been identified without performing the multifactor analysis of variance. Furthermore, layout was the only factor that tested different orientations of build layers (or layer-to-layer interfaces) with respect to the sample part, and thus, it appears that the orientation of the build layer (layer-to-layer interfaces) with respect to the fabricated part has a significant effect on the resulting mechanical properties. This study represents one of many to follow that is using statistical analyses to identify and classify important fabrication parameters on mechanical properties for layer-manufactured parts. Although SL is the focus of this work, the techniques developed and presented here can be applied to any layered manufacturing technology producing any ASTM-type specimen with any particular material.     

Comparative resistance of food proteins to adult and infant in vitro digestion models

IgE‐mediated allergy to milk and egg is widespread in industrialised countries and mainly affects infants and young children. It may be connected to an incomplete digestion of dietary proteins causing an inappropriate immune response in the gut. In order to study this, a biochemical model of infant gastroduodenal digestion has been developed, which has reduced levels of protease (eightfold for pepsin and tenfold for trypsin and chymotrypsin), phosphatidylcholine and bile salts, compared with the adult model. This model has been used to study the behaviour of three characterised food‐relevant proteins (bovine β‐lactoglobulin (β‐Lg), β‐casein (β‐CN) and hen's egg ovalbumin), all of which are relevant cows' milk and hens' egg allergens. Digestion products were characterised using electrophoresis, immunochemical techniques and MS. These showed that ovalbumin and β‐CN were digested more slowly using the infant model compared with the adult conditions. Resistant fragments of β‐CN were found in the infant model, which correspond to previously identified IgE epitopes. Surprisingly, β‐Lg was more extensively degraded in the infant model compared with the adult one. This difference was attributed to the tenfold reduction in phosphatidylcholine concentration in the infant model limiting the protective effect of this phospholipid on β‐Lg digestion.     

Food processing increases casein resistance to simulated infant digestion

The objective of this study was to determine whether processing could modify the resistance of casein (CN) to digestion in infants. A range of different dairy matrices was manufactured from raw milk in a pilot plant and subjected to in vitro digestion using an infant gut model. Digestion products were identified using MS and immunochemical techniques. Results obtained showed that CNs were able to resist digestion, particularly κ‐ and αs₂‐CN. Resistant areas were identified and corresponded to fragments hydrophobic at pH 3.0 (gastric conditions) and/or carrying post‐translational modifications (phosphorylation and glycosylation). Milk processing led to differences in peptide patterns and heat treatment of milk tended to increase the number of peptides found in digested samples. This highlights the likely impact of milk processing on the allergenic potential of CNs.     

Freezing step controls the mannitol phase composition heterogeneity

Freeze-dried samples were prepared from D-mannitol solution by selected freezing conditions. Crystalline structures of prepared samples were determined by XRD analysis, and distributions of the various crystal structures of mannitol were obtained for each sample. It was found that the amount of each polymorph was quite well correlated to the freezing conditions, namely the ice crystal nucleation temperature and the cooling rate. In case of samples prepared at fast cooling rates, the samples where the ice crystals nucleated at higher temperature contained much more stable form than the samples nucleated at lower temperature. Besides, the samples prepared at slow cooling rates predominantly contained stable crystalline forms despite of the variation of nucleation temperatures. Moreover, the experimental results also indicated that the various polymorphs were also distributed vertically through the sample along the direction of the heat flux during freezing. The tendency of the polymorph distribution through the freeze-dried cake was also elucidated by using the simulated temperature profiles during freezing. Thus, the profiles of mannitol polymorphs after the freezing derived from the temperature distributions could predict the global tendency of polymorphism behaviour, and, consequently, would be useful to achieve quality control of freeze-dried formulations.     

Hydrodynamic and mass transfer efficiency of ceramic foam packing applied to distillation

In addition to a high void volume and specific area, solid foams possess other properties (low density, good thermal, mechanical, electrical, and acoustical behaviour) that make them attractive for applications such as heat exchangers and reformers. Applications using foams as catalysts or structured catalyst supports have demonstrated higher performance than classical catalysts. Several studies have explored the hydrodynamic behaviour of foams in monophasic and countercurrent systems and have reported very low pressure drops. This paper describes the application of ceramic foam to distillation. The β-SiC foam contains 5 pores per inch (PPI) with a 91% void volume and a surface area of 640 m²/m³. Performance parameters including pressure drop for the dry and wet packing, flooding behaviour, and dynamic liquid hold-up were measured in a column of 150 mm internal diameter. The mass transfer efficiency in terms of the height equivalent to theoretical plate (HETP) was determined by total reflux experiments using a mixture of n-heptane and cyclohexane at atmospheric pressure. The experimental results were used to develop a set of correlations describing pressure drop and liquid hold-up in terms of a dimensionless number. The hydrodynamic performance and mass transfer efficiency were compared with classical packing materials used in distillation.     

Antimicrobial resistance of fecal bacteria in waters of the Seine river watershed (France)

We studied the prevalences of antimicrobial resistance (AR) and multiple antimicrobial resistance (MAR) among the fecal bacteria found in the rivers of a large watershed under strong anthropogenic pressures, the Seine river watershed (France). Two groups of fecal indicator bacteria, Escherichia coli and intestinal enterococci, were tested for their susceptibility to 16 and 10 antimicrobials respectively, using the disk diffusion method. We found that 42% of the 214 E. coli river isolates were AR (resistant to at least one antimicrobial) and 35% were MAR (resistant to at least two antimicrobials). Among the 148 intestinal enterococci isolates from rivers, 83% were AR and 49% were MAR. We also investigated the sources of AR fecal bacteria found in the rivers of the watershed. A total of 715 E. coli isolates and 476 intestinal enterococci isolates were collected in point sources (municipal and hospital wastewaters) and non-point sources (surface runoff and soil leaching waters from agricultural or forest areas). For E. coli, the prevalence of AR differed widely from source to source and ranked in this order: hospital wastewaters (71%) > municipal wastewaters (44%) > agricultural non-point sources (16%) > forest non-point sources (2%). The prevalence of MAR ranked similarly, and the same trend was observed for intestinal enterococci. The AR level of fecal bacteria in the sources was related to their expected exposure level to antimicrobials before their release into the environment. A MAR index was calculated for every source and a good discrimination between them was thus obtained. At the global scale of the Seine river watershed, domestic wastewaters seemed more likely to be the predominant source of the AR fecal bacteria found in the rivers. This was corroborated by the similarity of the MAR indices from river and municipal wastewater isolates for both fecal indicators.     

Experimental Analysis and Wear Prediction Model for Unfilled Polymer–Polymer Sliding Contacts

Lifetime prediction of polymer–polymer contacts is a major challenge. Current design methods stemming from metal contact surfaces lack accuracy because polymers behave differently, especially regarding temperature variations. Experiments were performed on a pin-on-disk setup alternating static and rotating elements. Common unfilled engineering polymers, viz. polyoxymethylene (POM), polypropylene (PP), polyamide 6.6 (PA6.6), and polycarbonate (PC) were tested at ambient and elevated temperatures. Material combinations were analyzed regarding the effects of load, velocity, temperature, and the product of contact pressure and sliding velocity (PV limit). The experimental results show that the PV limit is not predictive for polymer–polymer contacts; rather, each material combination has a critical factor that determines the wear and frictional values and thus the contact’s durability and lifetime. The critical factor is the value of contact pressure or sliding velocity or temperature at which there is sudden increase in wear rate. The experimental results also demonstrate that the application temperature in operation has an important influence on the lifetime. A temperature increase can either be beneficial or have a negative impact depending on the material combination. Resulting from the extensive experimental analysis, a new design method, based on the principle of deformation energy, is proposed. The new model is different from existing models because it includes thermal properties of the materials in contact and it makes use of the Péclet number. Because the proposed model requires only data sheet values and design parameters to predict wear volume, the model improves the support of engineers in designing durable polymer–polymer sliding contacts.     

Rational Structure-Based Design of Fluorescent Probes for Amyloid Folds

Amyloid fibrils are pathological hallmarks of various human diseases, including Parkinson's, Alzheimer's, amyotrophic lateral sclerosis (ALS or motor neurone disease), and prion diseases. Treatment of the amyloid diseases are hindered, among other factors, by timely detection and therefore, early detection of the amyloid fibrils would be beneficial for treatment against these disorders. Here, a small molecular fluorescent probe is reported that selectively recognize the fibrillar form of amyloid beta(1–42), α-synuclein, and HET-s(218–289) protein over their monomeric conformation. The rational design of the reporters relies on the well-known cross-β-sheet repetition motif, the key structural feature of amyloids.