Study on lipid fractions of Streptococcus thermophilus by TLC, GC and GC/MS techniques

In this research the lipid fraction of two strains of Streptococcus thermophilus was studied. Lipids were extracted by applying Folch method and fractioned by thin layer chromatography (TLC). Fatty acid composition was determined both before TLC, on the total fat extracted, and after TLC on diacylglycerol and apolar fractions. Gas chromatographic analysis was performed by using both flame ionization (FID) and mass spectrometer (MS) detector. The main difference between the two strains was the presence of short and medium chain fatty acids in food-born S. thermophilus. Moreover one of the most important bacterial fatty acids, C19 cyclopropane, was detected only in diacylglycerols, which, as reported in literature, are formed transiently as intermediates in the biosynthesis of glycerophospholipids

Effectiveness comparison between carbon spring and hinged ankle-foot orthoses in crouch gait treatment of children with diplegic cerebral palsy: A randomized crossover trial

BACKGROUND: Children with cerebral palsy (CP) often present a loss of effectiveness of the plantarflexors/knee-extensors couple that leads to crouch gait. When treating a child with crouch gait by means of ankle foot orthoses, preserving or restoring push off power is a key issue.AIM: To compare carbon-fiber spring (Carbon Ankle Seven (R) [CAFO], Ottobock (R) HealthCare, Duderstadt, Germany) and hinged ankle-foot orthoses (HAFO) effectiveness in improving functionality and walking ability in children with diplegic CP and crouch gait.DESIGN: Randomized crossover trial.SETTING: Hospital center.POPULATION: Ten children with diplegic CP and crouch gait, 5 males and 5 females, aged 11 (4) years.METHODS: The gait of each child was evaluated by means of instrumental gait analysis with both CAFO and HAFO, in a randomized order and after a 4-week adaptation period. The primary outcome measure was the change in ankle power generation. As secondary outcome measures, knee joint kinematics, stride length, walking speed, Observational Gait Scale, and preferred orthosis were considered.RESULTS: The median of the energy produced in stance was superior with CAFO (+2.2 J/kg, IQR 4.7, P=0.006), and the energy absorbed inferior (-3.3 J/kg, IQR 4.3, P=0.011). No statistically significant difference was found for any other parameter. Preference of the children was equally distributed between the two orthoses.CONCLUSIONS: No evident superiority of CAFO with respect to HAFO was found in improving gait performance of children with CP and crouch gait. Nevertheless, the results suggest the possibility that CAFO permits an energy saving and reduction of the more compromising deficits.CLINICAL REHABILITATION IMPACT: The final choice of the participants indicates that CAFOs are preferred by older and heavier children, but the preference does not correlate with the performance of the orthoses during gait

Influence of Processing Parameters and Natural Antimicrobial on Alicyclobacillus acidoterrestris and Clostridium pasteurianum Using Response Surface Methodology

The food industry must ensure the stability of the products, and this is often achieved by exposing foods to heat treatments that are able to ensure the absence of pathogenic or spoilage microorganisms. These treatments are different in terms of temperature and duration and could lead to a loss in nutritional and sensory value. Moreover, some types of microorganisms manage to survive these treatments thanks to the sporification process. The addition of antimicrobials can become necessary, but at present, consumers are more inclined toward natural products, avoiding synthetic and chemical additives. Antimicrobials from plants could be a valuable option and, in this context, a patent concerning an antimicrobial extract from fermented plant substrate was recently tested against foodborne pathogens revealing high antimicrobial activity. The objective of this study was the creation of a model for the evaluation and subsequent prediction of the combined effect of different process and product variables, including antimicrobial addition, on the inhibition and reduction of spore germination of target microorganisms, Alicyclobacillus acidoterrestris and Clostridium pasteurianum, responsible for spoilage of tomato-based products

Sourdough bacterial dynamics revealed by metagenomic analysis in Brazil.

This study dealt with the influence of the temperature on the bacterial dynamics of two spontaneously fermented wheat sourdoughs, propagated at 21 ± 1 °C (SD1) and 30 ± 1 °C (SD2), during nine backslopping steps (BS1 to BS9). Proteobacteria was the only phylum found in flour. Escherichia hermannii was predominant, followed by Kosakonia cowanii, besides species belonging to the genera Pantoea and Pseudomonas. After one step of propagation, Clostridium and Bacillus cereus group became predominant. Lactobacillus curvatus was found at low relative abundance. For the second backslopping step, Clostridium was flanked by L. curvatus and Lactobacillus farciminis. From BS4 (6th day) onward, lactic acid bacteria (LAB) became predominant. L. farciminis overcame L. curvatus and remained dominant until the end of propagations for both sourdoughs. At 21 °C, Bacillus, Clostridium, Pseudomonas, and Enterobacteriaceae were gradually inhibited. At the end of propagation, SD1 harbored only LAB. Otherwise, the temperature of 30 °C favored the persistence of atypical bacteria in SD2, as Pseudomonas and Enterobacteriaceae. Therefore, the temperature of 21 °C was more suitable for sourdough propagation in Brazil. This study enhanced the knowledge of temperature's influence on microbial assembly and contributed to the elucidation of sourdough microbial communities in Brazil

The capture of extracellular vesicles endogenously released by xenotransplanted tumours induces an inflammatory reaction in the premetastatic niche

The capture of tumour-derived extracellular vesicles (TEVs) by cells in the tumour microenvironment (TME) contributes to metastasis and notably to the formation of the pre-metastatic niche (PMN). However, due to the challenges associated with modelling release of small EVs in vivo, the kinetics of PMN formation in response to endogenously released TEVs have not been examined. Here, we have studied the endogenous release of TEVs in mice orthotopically implanted with metastatic human melanoma (MEL) and neuroblastoma (NB) cells releasing GFP-tagged EVs (GFTEVs) and their capture by host cells to demonstrate the active contribution of TEVs to metastasis. Human GFTEVs captured by mouse macrophages in vitro resulted in transfer of GFP vesicles and the human exosomal miR-1246. Mice orthotopically implanted with MEL or NB cells showed the presence of TEVs in the blood between 5 and 28 days after implantation. Moreover, kinetic analysis of TEV capture by resident cells relative to the arrival and outgrowth of TEV-producing tumour cells in metastatic organs demonstrated that the capture of TEVs by lung and liver cells precedes the homing of metastatic tumour cells, consistent with the critical roles of TEVs in PMN formation. Importantly, TEV capture at future sites of metastasis was associated with the transfer of miR-1246 to lung macrophages, liver macrophages, and stellate cells. This is the first demonstration that the capture of endogenously released TEVs is organotropic as demonstrated by the presence of TEV-capturing cells only in metastatic organs and their absence in non-metastatic organs. The capture of TEVs in the PMN induced dynamic changes in inflammatory gene expression which evolved to a pro-tumorigenic reaction as the niche progressed to the metastatic state. Thus, our work describes a novel approach to TEV tracking in vivo that provides additional insights into their role in the earliest stages of metastatic progression.The authors would like to thank Mrs. J. Rosenberg for her help in the formatting of the manuscript, and the personnel of the Core Facilities of the Saban Research Institute at Children's Hospital Los Angeles (Flow Cytometry, Extracellular Vesicle, Cell Imaging, and Animal Imaging Cores) for their expertise and assistance. This work was supported by National Institutes of Health/National Cancer Institute grant R01 CA207983 to Y.A. DeClerck

Compact Modeling of Nonideal Trapping/Detrapping Processes in GaN Power Devices

Compact modeling of charge trapping processes in GaN transistors is of fundamental importance for advanced circuit design. The goal of this article is to propose a methodology for modeling the dynamic characteristics of GaN power HEMTs in the realistic case where trapping/detrapping kinetics are described by stretched exponentials, contrary to ideal pure exponentials, thus significantly improving the state of the art. The analysis is based on: 1) an accurate methodology for describing stretched-exponential transients and extracting the related parameters and 2) a novel compact modeling approach, where the stretched exponential behavior is reproduced via multiple RC networks, whose parameters are specifically tuned based on the results of 1). The developed compact model is then used to simulate the transient performance of the HEMT devices as a function of duty cycle and frequency, thus providing insight on the impact of traps during the realistic switching operatio

Exploration of Gate Trench Module for Vertical GaN devices

The aim of this work is to present the optimization of the gate trench module for use in vertical GaN devices in terms of cleaning process of the etched surface of the gate trench, thickness of gate dielectric and magnesium concentration of the p-GaN layer. The analysis was carried out by comparing the main DC parameters of devices that differ in surface cleaning process of the gate trench, gate dielectric thickness, and body layer doping. . On the basis of experimental results, we report that: (i) a good cleaning process of the etched GaN surface of the gate trench is a key factor to enhance the device performance, (ii) a gate dielectric >35-nm SiO2 results in a narrow distribution for DC characteristics, (iii) lowering the p-doping in the body layer improves the ON-resistance (RON). Gate capacitance measurements are performed to further confirm the results. Hypotheses on dielectric trapping/detrapping mechanisms under positive and negative gate bias are reported.Comment: 5 pages, 10 figures, submitted to Microelectronics Reliability (Special Issue: 31st European Symposium on Reliability of Electron Devices, Failure Physics and Analysis, ESREF 2020