The objective of this research was to evaluate the influence of static electric field (SEF) on the freezing of pork meat (pork tenderloin muscle) with respect to the size of ice crystal formulation. ...The results showed that by increasing the strength of the static electric field, the degree of supercooling was reduced. The measured degree of supercooling varied from 3.93±1.3°C to 1.92±1.45°C for the control and the frozen sample under 12kV SEF, respectively. Meat microstructure was investigated after Carnoy fixation of the frozen tissues. The overall relative surface of the ice crystals was unchanged. The average equivalent circular diameter of the ice crystals was significantly reduced with increasing SEF; values from 32.79±4.04μm for the control to 14.55±8.20μm for the sample frozen at the maximum magnitude electric field which was tested were observed respectively. These findings demonstrate clearly the advantage of freezing under SEF which appears as a promising and innovative freezing process for food systems.
The reduction of freeze damage exerted to any tissue undergoing freezing remains a challenge. The mechanical and biochemical stress caused by the ice crystals to the cellular membranes results in irreversible tissue damage. Freezing under static electric field (SEF) has been identified as a possible means to reduce the size of ice crystals during freezing of biological tissues. In the present study SEF was applied during freezing of pork meat. Our results indicate that the size of the formed ice crystals was significantly reduced under SEF freezing leading to a lower damage on the microstructure of meat. This paper describes an innovative freezing process that could be used in order for higher quality frozen products to be produced.
•Freezing under static electric field has been investigated with pork meat.•The size of ice crystals was reduced by 56% between control and higher field level.•The tortuosity of ice crystals was increased by 4% between control and higher field level.
Sheep are one of the many animal models used to investigate the pathophysiology of disc degeneration and the regenerative strategies for intervertebral disc (IVD) disease. To date, few studies have ...thoroughly explored ageing of ovine lumbar IVDs. Hence, the objective of the present study was to concomitantly assess the development of spontaneous age-related lumbar IVD degeneration in sheep using X-ray, magnetic resonance imaging (MRI) as well as histological analyses. 8 young ewes (< 48 months old) and 4 skeletally mature ewes (> 48 months old) were included. Disc height, Pfirrmann and modified Pfirrmann grades as well as T2-wsi and T2 times were assessed by X-ray and MRI. The modified Boos score was also determined using histology sections. Pfirrmann (2 to 3) and modified Pfirrmann (2 to 4) grades as well as Boos scores (7 to 13) gradually increased with ageing, while T2-weighted signal intensity (1.18 to 0.75), T2 relaxation time (114.36 to 70.65 ms) and disc height (4.1 to 3.2 mm) decreased significantly. All the imaging modalities strongly correlated with the histology (p < 0.0001). The present study described the suitability of sheep as a model of age-related IVD degeneration by correlation of histological tissue alterations with the changes observed using X-ray and MRI. Given the structural similarities with humans, the study demonstrated that sheep warrant being considered as a pertinent animal model to investigate IVD regenerative strategies without induction of degeneration.
Summary
Experimentation platforms are essential to large modern technology companies, as they are used to carry out many randomized experiments daily. The classic assumption of no interference among ...users, under which the outcome for one user does not depend on the treatment assigned to other users, is rarely tenable on such platforms. Here, we introduce an experimental design strategy for testing whether this assumption holds. Our approach is in the spirit of the Durbin–Wu–Hausman test for endogeneity in econometrics, where multiple estimators return the same estimate if and only if the null hypothesis holds. The design that we introduce makes no assumptions on the interference model between units, nor on the network among the units, and has a sharp bound on the variance and an implied analytical bound on the Type I error rate. We discuss how to apply the proposed design strategy to large experimentation platforms, and we illustrate it in the context of an experiment on the LinkedIn platform.
Stimuli-responsive, “smart” polymeric materials used in the biomedical field function in a bio-mimicking manner by providing a non-linear response to triggers coming from a physiological ...microenvironment or other external source. They are built based on various chemical, physical, and biological tools that enable pH and/or temperature-stimulated changes in structural or physicochemical attributes, like shape, volume, solubility, supramolecular arrangement, and others. This review touches on some particular developments on the topic of stimuli-sensitive molecular tools for biomedical applications. Design and mechanistic details are provided concerning the smart synthetic instruments that are employed to prepare supra- and macro-molecular architectures with specific responses to external stimuli. Five major themes are approached: (i) temperature- and pH-responsive systems for controlled drug delivery; (ii) glycodynameric hydrogels for drug delivery; (iii) polymeric non-viral vectors for gene delivery; (iv) metallic nanoconjugates for biomedical applications; and, (v) smart organic tools for biomedical imaging.
This paper is focused on the study of a new low frequency micro and nanoforce sensor based on diamagnetic levitation. The force sensitive part is a 10-cm long macroscopic capillary tube used as a ...levitating seismic mass. This tube presents a naturally stable equilibrium state with six degrees of freedom thanks to the combination of diamagnetic repulsive and magnetic attractive forces. It is only used as a one-direction force sensing device along its longitudinal axis. This force sensor is passive. The force measurement is based on the displacement of the capillary tube and in steady-state this displacement is proportional to the force. This sensor is characterized by an under-damped second-order linear force–displacement dynamic which remains linear on several hundred micrometers and can thus measure a wide range of microforces. Because of the magnetic springs configuration used, the capillary tube presents a horizontal mechanical stiffness that can be adjusted between 0.01 and 0.03
N/m (similar to the stiffness of a thin AFM cantilever). The measurement range typically varies between ±50
μN. Bandwidth is 4
Hz. The resolution depends on the sensor used to measure the capillary tube displacement and on noises induced by environmental conditions (ground and air vibrations). The resolution typically reached with a STIL confocal chromatic sensor is 5
nN inside a test chamber located on a anti-vibration table. This study is illustrated by a pull-off force measurement.
Although previous studies on N2-fixing legumes have demonstrated the contribution of acid phosphatases to their phosphorus (P) use efficiency under P-deficient growth conditions, localization of ...these enzymes in bean nodules has not been demonstrated. In this study, phosphoenol pyruvate phosphatase (PEPase) gene transcripts were localized within the nodule tissues of two recombinant inbred lines, RIL115 (P-deficiency tolerant) and RIL147 (P-deficiency sensitive), of Phaseolus vulgaris. Nodules were induced by Rhizobium tropici CIAT899 under hydroaeroponic conditions with a sufficient versus a deficient P supply. The results indicated that PEPase transcripts were particularly abundant in the nodule infected zone and cortex of both RILs. Analysis of fluorescence intensity indicated that nodule PEPase was induced under conditions of P deficiency to a significantly higher extent in RIL147 than in RIL115, and more in the inner cortex (91%) than in the outer cortex (71%) or the infected zone (79%). In addition, a significant increase (39%) in PEPase enzyme activity in the P-deficient RIL147 correlated with an increase (58%) in the efficiency of use in rhizobial symbiosis. It was concluded that nodule PEPase is upregulated under conditions of P deficiency in the P-deficiency-sensitive RIL147, and that this gene may contribute to adaptation of rhizobial symbiosis to low-P environments.
•Lipidomics, high resolution mass spectrometry, polarity switching, serum, canine mammary cancer.
Lipids represent an extended class of substances characterized by such high variety and complexity ...that makes their unified analyses by liquid chromatography coupled to either high resolution or tandem mass spectrometry (LC–HRMS or LC–MS/MS) a real challenge. In the present study, a new versatile methodology associating ultra high performance liquid chromatography coupled to high resolution tandem mass spectrometry (UHPLC–HRMS/MS) have been developed for a comprehensive analysis of lipids. The use of polarity switching and “all ion fragmentation” (AIF) have been two action levels particularly exploited to finally permit the detection and identification of a multi-class and multi-analyte extended range of lipids in a single run. For identification purposes, both higher energy collision dissociation (HCD) and in-source CID (collision induced dissociation) fragmentation were evaluated in order to obtain information about the precursor and product ions in the same spectra. This approach provides both class-specific and lipid-specific fragments, enhancing lipid identification. Finally, the developed method was applied for differential phenotyping of serum samples collected from pet dogs developing spontaneous malignant mammary tumors and health controls. A biological signature associated with the presence of cancer was then successfully revealed from this lipidome analysis, which required to be further investigated and confirmed at larger scale.
Canine Mammary Tumors Peña, L.; Gama, A.; Goldschmidt, M. H. ...
Veterinary pathology,
01/2014, Letnik:
51, Številka:
1
Journal Article
Recenzirano
Although there have been several studies on the use of immunohistochemical biomarkers of canine mammary tumors (CMTs), the results are difficult to compare. This article provides guidelines on the ...most useful immunohistochemical markers to standardize their use and understand how outcomes are measured, thus ensuring reproducibility of results. We have reviewed the biomarkers of canine mammary epithelial and myoepithelial cells and identified those biomarkers that are most useful and those biomarkers for invasion and lymph node micrometastatic disease. A 10% threshold for positive reaction for most of these markers is recommended. Guidelines on immunolabeling for HER2, estrogen receptors (ERs), and progesterone receptors (PRs) are provided along with the specific recommendations for interpretation of the results for each of these biomarkers in CMTs. Only 3+ HER2-positive tumors should be considered positive, as found in human breast cancer. The lack of any known response to adjuvant endocrine therapy of ER- and PR-positive CMTs prevents the use of the biological positive/negative threshold used in human breast cancer. Immunohistochemistry results of ER and PR in CMTs should be reported as the sum of the percentage of positive cells and the intensity of immunolabeling (Allred score). Incorporation of these recommendations in future studies, either prospective or retrospective, will provide a mechanism for the direct comparison of studies and will help to determine whether these biomarkers have prognostic significance. Finally, these biomarkers may ascertain the most appropriate treatment(s) for canine malignant mammary neoplasms.
This article presents a new micro and nanoforce sensor used to perform a mechanical characterisation of human oocytes. This device is based on the use of low-stiffness magnetic springs. The oocytes ...to be characterised are placed on a force–sensitive platform. A manipulator equipped with a standard micropipette is used to mechanically compress the oocyte. Some complete “force–compression length” curves associated with mechanical load–unload cycles are given. These curves show the linear, the non-linear and also the plastic mechanical behaviour of the oocytes. These characterisations must be considered as a preliminary result which illustrates that the mechanical variability and the mechanical evolution of human oocytes during their maturation process can be observed with a force sensor based on magnetic springs.
A few species of shrubs grow with dryland row crops in farmers’ fields throughout the Sahel and can significantly increase crop yield. The presence of shrub roots and litter inputs should have ...implications for soil nutrient pool sizes but there is limited information on the interactions of these shrubs with microbial communities involved in biogeochemical processes. Therefore, the objective of this study was to determine the microbial composition and functional capacity of soil from the rooting zone of pearl millet (Pennisetum glaucum) grown in the presence or absence of the shrub Piliostigma reticulatum in Senegal. Soil samples were collected from a long-term field study where millet was cultivated alone or intercropped with P. reticulatum with annual incorporation of coppiced shrub residues. Higher nutrient contents and distinct differences in microbial communities (DGGE profiles) were found between soils from beneath the canopy compared to soil outside the influence of shrubs. The catabolic response profile (MicroResp™) showed that the soil microbial community at both shrub and non-shrub sampling locations, metabolized a wide range of substrates. Trehalose that can work as a signaling molecule was more rapidly degraded in the rooting zone of millet growing in the presence of P. reticulatum over millet alone. Urease, arylsulfatase and dehydrogenase activities in the millet root zone soil were higher when intercropped with P. reticulatum which indicates enhanced potential of biogeochemical processes to proceed in the presence of this shrub. It is concluded that the native shrub P. reticulatum promotes a more diverse and active microbial community in the rooting zone of millet and further indicates greater potential to perform decomposition and mineralize nutrients.
•Native shrubs might be used as part of Sub-Saharan small-farming systems.•The shrub altered both microbial DGGE-profiling and enzyme activities in millet soil.•Shrub effects on bacteria and fungi are mediated by soil chemical parameters.
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