Physicochemical properties of bacterial cellulose obtained from different Kombucha fermentation conditions

The production of bacterial cellulose has been limited due to its high cost and low productivity. Alternative low‐cost sources of this biopolymer of high purity and biocompatibility are needed in order to benefit from its enormous potential. Kombucha tea is a trend functional beverage whose production is growing exponentially worldwide, and the bacteria present in this fermented beverage belonging to the genus Komagataeibacter are capable of producing a crystalline biofilm with interesting properties. Obtaining bacterial cellulose from Kombucha tea has already been studied, however several fermentation conditions are being optimized in order to scale‐up its production. In this study, we characterized the bacterial cellulose produced from three different Kombucha fermentation conditions. The scanning electron microscopy images revealed the crystalline structure of the biofilms. The energy‐dispersive x‐ray analysis exhibited the chemical composition of the crystals. The thermogravimetric analysis showed a rate of degradation between 490 and 560°C and the differential scanning calorimetry confirmed the presence of crystalline and amorphous regions in the bacterial cellulose samples. The results suggested that crystalline cellulose could be obtained by varying the fermentation conditions of Kombucha tea

Association of the PHACTR1/EDN1 genetic locus with spontaneous coronary artery dissection

Background: Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndromes (ACS) afflicting predominantly younger to middle-aged women. Observational studies have reported a high prevalence of extracoronary vascular anomalies, especially fibromuscular dysplasia (FMD) and a low prevalence of coincidental cases of atherosclerosis. PHACTR1/EDN1 is a genetic risk locus for several vascular diseases, including FMD and coronary artery disease, with the putative causal noncoding variant at the rs9349379 locus acting as a potential enhancer for the endothelin-1 (EDN1) gene. Objectives: This study sought to test the association between the rs9349379 genotype and SCAD. Methods: Results from case control studies from France, United Kingdom, United States, and Australia were analyzed to test the association with SCAD risk, including age at first event, pregnancy-associated SCAD (P-SCAD), and recurrent SCAD. Results: The previously reported risk allele for FMD (rs9349379-A) was associated with a higher risk of SCAD in all studies. In a meta-analysis of 1,055 SCAD patients and 7,190 controls, the odds ratio (OR) was 1.67 (95% confidence interval [CI]: 1.50 to 1.86) per copy of rs9349379-A. In a subset of 491 SCAD patients, the OR estimate was found to be higher for the association with SCAD in patients without FMD (OR: 1.89; 95% CI: 1.53 to 2.33) than in SCAD cases with FMD (OR: 1.60; 95% CI: 1.28 to 1.99). There was no effect of genotype on age at first event, P-SCAD, or recurrence. Conclusions: The first genetic risk factor for SCAD was identified in the largest study conducted to date for this condition. This genetic link may contribute to the clinical overlap between SCAD and FMD

Suggestion for a unified performance assessment criterion of spacecraft propellants

Propellant performance is usually assessed through the comparison of either the specific impulse Isp or the specific impulse density Isp,d of different propellants. However, each of these performance parameters could result in a different ranking of the propellants performances which makes it harder to make a suitable choice without having in mind an actual application. In order to overcome this problem, a unified performance assessment criterion based on both of these usual performance parameters is suggested in the present paper. The relevance of this unified performance assessment criterion has been shown over a wide range of propellants (mono and bi-propellants) for several in-service spacecrafts

The Unified Specific Impulse – A Selection Criterion For Green Propellants?

Propellant performance is usually assessed through the comparison of either the specific impulse Isp or the specific impulse density Isp,d of different propellants. However, each of these performance parameters could result in a different ranking of the propellants performances which makes it harder to make a suitable choice without having in mind an actual application. In order to overcome this problem, a unified performance assessment criterion based on both of these usual performance parameters is suggested in the present paper. The relevance of this unified performance assessment criterion has been shown over a wide range of propellants (mono and bi-propellants) for several in-service spacecrafts

Suggestion for the Unified Specific Impulse as an Alternative Selection Criterion for Green Propellants

Propellant performance is usually assessed through the comparison of either the specific impulse Isp or the specific impulse density Isp,d of different propellants. However, each of these performance parameters could result in a different ranking of the propellants performances which makes it harder to make a suitable choice without having in mind an actual application. In order to overcome this problem, a unified performance assessment criterion based on both of these usual performance parameters is suggested in the present paper. The relevance of this unified performance assessment criterion has been shown over a wide range of propellants (mono and bipropellants) for several in-service spacecrafts

Modeling of the Internal Hydrogen Embrittlement Effects on the Fatigue Life of a Structure Using a Commercial F.E. Program

An original and intuitive methodology has been developed within the framework of the European Union Seventh Framework Programme to rapidly get as a first assessment of the drop magnitude in high cycle fatigue (HCF) life duration of a structure at high temperatures due to internal hydrogen embrittlement at steady state hydrogen concentration conditions

A First Step Into Modeling Hydrogen Embrittlement with a Commercial Finite Element Program

Considering a quick set-up of numerical simulations of hydrogen embrittlement, the implementation of hydrogen embrittlement models into commercial Finite Element programs is an attractive alternative to in-house developed hydrogen embrittlement modeling codes. The purpose of this paper is to briefly discuss the first step into modeling the isothermal stationary hydrogen embrittlement through the implementation of a hydrogen embrittlement model based on the hydrogen-induced enhanced plasticity (HELP) mechanism into a commercial Finite Element program. The consistency of the proposed methodology has been assessed by the analysis of Finite Element simulation results of an isothermal stationary stressed ultrasonic HCF test sample with and without considering the influence of hydrogen

Organic Computing at the System on Chip Level

Abstract—The evolution of CMOS technologies leads to integrated circuits with ever smaller device sizes, lower supply voltage, higher clock frequency and more process variability. Intermittent faults effecting logic and timing are becoming a major challenge for future integrated circuit designs. This paper presents an Organic Computing inspired SoC architecture which applies self-organization and self-calibration concepts to build reliable SoCs with lower overheads and a broader fault coverage than classical fault-tolerance techniques. We demonstrate the feasibility of this approach by example on the processing pipeline of a public-domain RISC CPU core. I