Combined Nano‐ and Micro‐Scale Topographic Cues for Engineered Vascular Constructs by Electrospinning and Imprinted Micro‐Patterns

The major cause of synthetic vessel failure is thrombus and neointima formation. To prevent these problems the creation of a continuous and elongated endothelium inside lumen vascular grafts might be a promising solution for tissue engineering. Different micro‐ and nano‐surface topographic cues including grooved micro‐patterns and electrospun fibers have been previously demonstrated to guide the uniform alignment of endothelial cells (ECs). Here, with a very simple and highly versatile approach we combined electrospinning with soft lithography to fabricate nanofibrous scaffolds with oriented fibers modulated by different micro‐grooved topographies. The effect of these scaffolds on the behavior of the ECs are analyzed, including their elongation, spreading, proliferation, and functioning using unpatterned random and aligned nanofibers (NFs) as controls. It is demonstrated that both aligned NFs and micro‐patterns effectively influence the cellular response, and that a proper combination of topographic parameters, exploiting the synergistic effects of micro‐scale and sub‐micrometer features, can promote EC elongation, allowing the creation of a confluent ECs monolayer in analogy with the natural endothelium as assessed by the positive expression of vinculin. Combining different micro‐ and nano‐topographic cues by complementary soft patterning and spinning technologies could open interesting perspectives for engineered vascular replacement constructions.     

The influence of oxidizing agents on water extracts of rye flour

The main constituents of rye flour extracts are proteins and pentosans. After cross-linking under the action of oxidizing agents those components are able to bind much more water than in their native (prior to modifications) state. As a consequence rheological properties of extract are changed.It was observed that kinematic viscosity of water extract of rye flour decreases rapidly with time. The reason for this behavior could be high enzymatic activity of flour extract.It was also found that the addition of hydrogen peroxide in the absence of additional peroxidase (which is naturally present in 1:9 or 1:1 water extracts of flour) causes the greatest increase in viscosity, due to the cross-linking of soluble polymers. Moreover after the addition of H₂O₂ to water extracts strong gels were obtained, which were characterized by tan δ = 0.5 (tan δ < 1). Moreover G′ was independent of frequency, which also suggests cross-linking of the pentosans.The addition of ascorbic acid, which is known to act preferably on gluten proteins, to 1:9 or 1:1 flour extracts had only a little effect on viscosity. In this case the values of tan δ = 0.9 were close to 1, which is typical for a weak gel.The application of inactivated rye flour extract, containing mainly proteins and pentosans, proved stronger effect of H₂O₂ in comparison to ascorbic acid on polymer cross-linking, but only after the addition of peroxidase. The gel obtained with H₂O₂ and peroxidase was also characterized by low tan δ = 0.4.The results indicate, that pentosans are the main subject of cross-linking reactions in rye flour water extracts.     

Determination of (fluoro)quinolones in eggs by liquid chromatography with fluorescence detection and confirmation by liquid chromatography-tandem mass spectrometry

A multiresidue analytical procedure for determination of seven fluoroquinolones (marbofloxacin, norfloxacin as internal standard, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin and difloxacin), and three quinolones (oxolinic acid, nalidixic acid and flumequine) in eggs is presented. The procedure is based on dispersive solid-phase extraction technique with acetonitrile as extractant. Norfloxacin and ciprofloxacin - d8 were used as internal standards to quantify the (fluoro)quinolones. Analyses were realised by LC-FLD for screening and LC-MS/MS for confirmatory purposes. The whole procedure was evaluated according to the Commission Decision 2002/657/EC. Specificity, decision limit (CCα), detection capacity (CCβ), recovery (absolute and relative), precision (repeatability and reproducibility) were determined during validation process. Recoveries (relative) for the LC-FLD screening determination ranged from 85% to 93%, repeatability and reproducibility were in the range of 5-9% to 9-16%, respectively. CCα and CCβ were 13-37 and 17-43 μg/kg pending on analite. For the LC-MS/MS confirmatory method, the relative recoveries were satisfactory (92-99%) with repeatability and reproducibility in the range of 4-7% to 6-12%, respectively. CCα and CCβ were 3-7 and 7-11 μg/kg depending on the analite. The results of both prepared methods showed these analytical procedures simple, rapid, sensitive and suitable for routine control of eggs.     

Organic whey as a source of Lactobacillus strains with selected technological and antimicrobial properties

Twenty‐five strains, isolated from raw, non‐pasteurised, organic whey samples, were identified phenotypically and genotypically. Biochemical tests were performed, and enzyme profiles, antibiotic resistance and antimicrobial properties were investigated. Sixteen strains were identified as genus Lactobacillus. Based on 16S rDNA gene sequence, the strains were identified as Lb. plantarum and Lb. fermentum. All of the strains had β‐galactosidase activity, and some of them reduced nitrate content. All strains utilised carbohydrates. The tested strains were characterised by low or average lipolytic and esterolytic activity. Moreover, the strains showed low proteolytic activity which is advantageous for their use as starter cultures for foods with low protein content. Strains Lb. fermentum S20, SM1, SM3, S2R and Lb. plantarum SM5 produced harmful N‐acetyl‐β‐glucosaminidase; moreover, the strain S20 produced also β‐glucuronidase. None of the strains produced α‐chymotrypsin. In phenotypic studies, most of the test strains were susceptible to gentamicin, ampicillin, tetracycline, chloramphenicol, penicillin and erythromycin. Strains Lb. plantarum S1 and Lb. fermentum S4, S7, S8, S10, SM1 and SM3 did not possess any transfer resistance genes. Antagonistic activity of the culture LAB strains was assessed as high or moderate in relation to the indicator strains, with the greatest zones of inhibition for E.coli and the smallest for L. monocytogenes ATCC 15313. This study reveals that the LAB strains isolated from organic whey have high potential for food application. Some strains of species Lb. fermentum (S4, S7, S8, S10) have been identified as the best candidates.     

Inactivation of Shiga toxin-producing O157:H7 and non-O157:H7 Shiga toxin-producing Escherichia coli in brine-injected, gas-grilled steaks

We quantified translocation of Escherichia coli O157:H7 (ECOH) and non-O157:H7 verocytotoxigenic E. coli (STEC) into beef subprimals after brine injection and subsequently monitored their viability after cooking steaks cut therefrom. Beef subprimals were inoculated on the lean side with ca. 6.0 log CFU/g of a five-strain cocktail of rifampin-resistant ECOH or kanamycin-resistant STEC, and then passed once through an automatic brine-injector tenderizer, with the lean side facing upward. Brine solutions (9.9% ± 0.3% over fresh weight) consisted of 3.3% (wt/vol) of sodium tripolyphosphate and 3.3% (wt/vol) of sodium chloride, prepared both with (Lac(+), pH = 6.76) and without (Lac(-), pH = 8.02) a 25% (vol/vol) solution of a 60% potassium lactate-sodium diacetate syrup. For all samples injected with Lac(-) or Lac(+) brine, levels of ECOH or STEC recovered from the topmost 1 cm (i.e., segment 1) of a core sample obtained from tenderized subprimals ranged from ca. 4.7 to 6.3 log CFU/g; however, it was possible to recover ECOH or STEC from all six segments of all cores tested. Next, brine-injected steaks from tenderized subprimals were cooked on a commercial open-flame gas grill to internal endpoint temperatures of either 37.8 °C (100 °F), 48.8 °C (120 °F), 60 °C (140 °F), or 71.1 °C (160 °F). Regardless of brine formulation or temperature, cooking achieved reductions (expressed as log CFU per gram) of 0.3 to 4.1 of ECOH and 0.5 to 3.6 of STEC. However, fortuitous survivors were recovered even at 71.1 °C (160 °F) for ECOH and for STEC. Thus, ECOH and STEC behaved similarly, relative to translocation and thermal destruction: Tenderization via brine injection transferred both pathogens throughout subprimals and cooking highly contaminated, brine-injected steaks on a commercial gas grill at 71.1 °C (160 °F) did not kill all cells due, primarily, to nonuniform heating (i.e., cold spots) within the meat.     

Genomic merit for reproductive traits. I: Estrous characteristics and fertility in Holstein heifers

Genetic selection of dairy cattle in the United States has included reproductive traits (daughter pregnancy rate, DPR; heifer conception rate, HCR), which is believed to have partly contributed to halting the decline in reproductive performance. The objectives of the current study were to evaluate the association among genomic merit for DPR (GDPR) and HCR (GHCR) with estrous characteristics measured by an automated device. Holstein heifers (n = 1,005) were genotyped at 2 mo of age and were classified into quartiles (Q1 = lowest, Q4 = highest) according to the GDPR and GHCR values of the study population. At 10 to 11 mo of age, heifers were fitted with a collar that recorded activity and rumination and determined the occurrence of estrus according to changes in activity and rumination compared with the individual's baseline values. Estrous characteristics of spontaneous estruses (SPE) and PGF_2α-synchronized estruses (PGSE) were recorded. Heifers had their estrous cycle synchronized with PGF_2α and following detection of estrus received either artificial insemination or embryo transfer according to the herd's genetic selection program. Heifers in Q2 (17.7 ± 0.3 h) of GHCR tended to have longer SPE than heifers in Q4 (16.7 ± 0.3 h). The interaction between GDPR and GHCR was associated with the likelihood of activity peak (0 = no estrus, 100 = maximum activity) ≥80 at SPE because, among heifers in Q3 and Q4 of GHCR, those in Q1 of GDPR were less likely to have an activity peak ≥80. Heifers in Q1 and Q2 of GDPR had reduced hazard of estrus within 7 d of the first PGF_2α treatment compared with heifers in Q4 of GDPR. Heifers in Q1 (16.1 ± 0.4 h) of GDPR had shorter PGSE than heifers in Q2 (17.6 ± 0.4 h) and Q4 (17.4 ± 0.4 h) and tended to have shorter PGSE than heifers in Q3 (17.4 ± 0.4 h). Rumination nadir on the day of PGSE was greater for heifers in Q1 (?30.1 ± 0.9 min/d) of GDPR compared with heifers in Q4 (?33.7 ± 0.9 min/d). Among heifers receiving only artificial insemination, those in Q1 of GHCR (adjusted hazard ratio = 0.65; 95% confidence interval = 0.48–0.88) became pregnant at a slower rate than heifers in Q4. Genomic merit for HCR was negatively associated with SPE but tended to be positively associated with hazard of pregnancy, whereas GDPR was positively associated with PGSE and hazard of estrus. Selection of dairy cattle for DPR and HCR may improve reproductive performance through different pathways, namely estrous characteristics and pregnancy establishment.     

Eliciting the Sensory Modalities of Fat Reformulated Yoghurt Ice Cream Using Oligosaccharides

In the present work, fat reduction of Greek strained yoghurt ice cream (YIC) was carried out in three proportional milkfat levels i.e. 30, 50 and 70% using three types of oligosaccharides namely long-chain inulin, oligofructose and maltodextrin 12 DE. Greek strained yoghurt was blended with ice cream mixes in ratios of 1:3 and 1:1. The physico-chemical, textural and thermal characteristics of the YIC mixes and their obtained frozen end products were determined. The sensory modalities (olfactory, gustatory, tactile and oro-tactile) of the YIC were monitored following 2 and 16 weeks of quiescent frozen storage at ?25 °C. Milkfat reduction impaired significantly (p?<?0.05) the perceived creaminess and mouthcoating sensation stimuli, whist it intensified the oral tissue friction associated sense stimuli such as astringency, wateriness and coarseness. Long-chain inulin- and maltodextrin-based samples received the highest scores for creaminess, mouthcoating, gumminess, hardness and iciness. The increase of the yoghurt to ice cream mix ratio escalated the friction/recrystallization-associated sensations e.g. astringency, sourness, coarseness and wateriness. Notwithstanding yoghurt supplementation reinforced the pseudoplasticity and macroviscosity of the ice cream mixes, it suppressed their aeration capacity leading to heavy-bodied ice creams. However, no significant effects of yoghurt supplementation level on the colligative and meltdown rate of the YIC formulations were identified. Partial least squares coupled discriminant analysis (PLS-DA) revealed that fat reformulation of YICs using oligosaccharides results in a substantially diversified sensory profile. Generally, a 50% fat reduction of YICs using long-chain oligosaccharides appears to be a technologically tangible solution.     

Bifidobacterium Bb-12 microencapsulated by spray drying with whey: Survival under simulated gastrointestinal conditions,tolerance to NaCl,and viability during storage

Bifidobacterium Bb-12 was microencapsulated by spray drying with whey. This present work investigated the survival of these microcapsules under simulated gastrointestinal conditions, as well as their tolerance to NaCl and their viability during storage. The results showed a small decrease in the viability of microencapsulated Bifidobacterium at low pH. In relation to the exposure of Bifidobacterium to bile, microencapsulation with whey did not protect the probiotic cells; however, the viability of the microcapsules remained >6 log cfu/g, even after 24 h of incubation at the highest bile concentration analyzed. No growth was noted with either the free cells or the microencapsulated cells on MRS-LP with NaCl. The viability of the microcapsules stored at 4 °C remained high and constant for 12 weeks. When the microcapsules were added to a dairy dessert, the probiotic count remained above 7 log cfu/g for 6 weeks. Therefore, whey is a promising encapsulating agent for Bifidobacterium Bb-12.