Psychrotrophic yeast Yarrowia lipolytica NCYC 789 mediates the synthesis of antimicrobial silver nanoparticles via cell-associated melanin

A psychrotrophic marine strain of the ascomycetous yeast Yarrowia lipolytica (NCYC 789) synthesized silver nanoparticles (AgNPs) in a cell-associated manner. These nanostructures were characterized by UV-Visible spectroscopy and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) analysis. The brown pigment (melanin) involved in metal-interactions was obtained from the cells. This extracted pigment also mediated the synthesis of silver nanoparticles that were characterized by a variety of analytical techniques. The melanin-derived nanoparticles displayed antibiofilm activity. This paper thus reports the synthesis of AgNPs by the biotechnologically important yeast Y. lipolytica; proposes a possible mechanism involved in the synthetic process and describes the use of the bio-inspired nanoparticles as antibiofilm agents

Contesting restrictive mobility norms among female mentors implementing a sport based programme for young girls in a Mumbai slum.

BACKGROUND: Harmful gender norms are known structural barriers to many public health and development interventions involving adolescent girls. In India, restrictions on girls' liberty to move freely in public spaces contribute to school dropout and early marriage, and negatively affect girls' health and wellbeing, from adolescence into adulthood. We report on mechanisms of change among female mentors 18 to 24 years old who contested discriminatory norms while implementing a sports-based programme for adolescent girls in a Mumbai slum. METHODS: We adopted a prospective qualitative research design. Our analysis is based on case studies derived from two rounds of face to face, in -depth interviews with 10 young women recruited to serve as mentors for the project's young female athletes. We combined both thematic and narrative analysis. RESULTS: The programme created opportunities for collective action, increasing mentors' ability to think and relate in a collectivized manner, and challenged the traditional female identity constructed for young women, which centres on domestic duties. The mentors themselves negotiated freedoms both in and outside their homes, which required careful and strategic bargaining. They changed the nature of key day-to-day social interactions with parents and brothers, as well as with neighbours, parents of their groups of athletes and men on the streets. They formed a new reference group for each other in terms of what was possible and acceptable. Demonstrating greater negotiation skills within the family helped win parents' trust in the mentor's ability to be safe in public spaces. Parents became active supporters by not giving into social sanctions of neighbours and relatives thus co-producing a new identity for their daughters as respectable young women doing 'good work'. They effectively side stepped reputational risk with their presence in public spaces becoming de-sexualised. CONCLUSIONS: Mentors contested mobility restrictions by taking risks as a group first, with collective agency an important step towards greater individual agency. This research provides important insights into addressing embedded social norms that perpetuate gender discriminatory practices and the social patterning of health inequalities

Nanoparticles in controlling biofilms of pathogenic bacteria

Bacteria form biofilms so as to protect themselves from physical and chemical assaults, which include antibiotic resistance where higher doses of antibiotics are needed. The purpose of this study was to come up with three different types of nanoparticles that would enhance the efficacy of antibiotics and decrease the amount of antibiotic needed to eliminate biofilm. The emphasis was on calcium peroxide nanoparticles along with tobramycin. These particles release oxygen and calcium that together had additive effects with tobramycin. Antibiotic concentrations required for biofilm eradication were reduced, as evidenced by colony forming unit assays, microscopy, qPCR and ex vivo assays on human oral biofilms. Squalenyl polymer nanoparticles have also been investigated and the reproducibility and stability of the nanoparticles were enhanced with the addition of surfactants. It also enhanced the efficacy of tobramycin and the dispersion of the biofilm. Lipid nanocapsules were employed in order to assess the ability of the size-dependent delivery of vancomycin and its efficacy against the Staphylococcus aureus biofilms. The smaller capsules were more efficient in penetrating through the biofilm while the larger ones released more of the active ingredient and enhanced the removal of the biofilm. This study proves the concept of nanoparticles in the treatment of biofilm and highlighted the efficacy of calcium peroxide nanoparticles at lower antibiotic concentrations.Bakterien bilden Biofilme, um sich vor physischen und chemischen Gefahren zu schützen, was die Antibiotikaresistenz erhöht und höhere Dosierungen erfordert. Ziel dieser Studie war die Entwicklung von drei Nanopartikeltypen, um die Wirksamkeit von Antibiotika zu verbessern und die Konzentration bei der Biofilmbeseitigung zu senken. Der Schwerpunkt lag auf Kalziumperoxid-Nanopartikeln in Kombination mit Tobramycin. Diese Partikel setzten Sauerstoff und Kalzium frei, was die Wirkung von Tobramycin verstärkte. Biofilme wurden bei geringeren Antibiotikakonzentrationen beseitigt, bestätigt durch CFU-Assays, Mikroskopie, qPCR und ex vivo-Tests an menschlichen oralen Biofilmen. Squalenyl-Polymer-Nanopartikel wurden ebenfalls untersucht, wobei die Reproduzierbarkeit und Stabilität durch den Einsatz von Tensiden verbessert wurde. Diese erhöhten auch die Wirksamkeit von Tobramycin und förderten die Biofilmbeseitigung. Lipidnanokapseln wurden verwendet, um größenabhängige Biofilmpenetration und Vancomycin-Freisetzung bei Staphylococcus aureus-Biofilmen zu untersuchen. Kleinere Kapseln drangen besser ein, größere transportierten mehr Wirkstoff und verbesserten die Biofilmbeseitigung. Diese Studie zeigt das Potenzial von Nanopartikeln in der Biofilmbehandlung, insbesondere die vielversprechenden Effekte von Kalziumperoxid-Nanopartikeln bei geringeren Antibiotikakonzentrationen

Marine yeast isolation and industrial application

Over the last century, terrestrial yeasts have been widely used in various industries, such as baking, brewing, wine, bioethanol and pharmaceutical protein production. However, only little attention has been given to marine yeasts. Recent research showed that marine yeasts have several unique and promising features over the terrestrial yeasts, for example higher osmosis tolerance, higher special chemical productivity and production of industrial enzymes. These indicate that marine yeasts have great potential to be applied in various industries. This review gathers the most recent techniques used for marine yeast isolation as well as the latest applications of marine yeast in bioethanol, pharmaceutical and enzyme production fields. Keyword

Lipid biosynthesis monitored at the single-cell level in Saccharomyces cerevisiae

There is increasing interest in bioengineering of lipids for use in functional foods, pharmaceuticals, and biofuels. Saccharomyces cerevisiae is a widely utilized cell factory for biotechnological production, thus a tempting alternative. Herein, we show how its neutral lipid accumulation varies throughout metabolic phases under nutritional conditions relevant for large-scale fermentation. Population-averaged metabolic data were correlated with lipid storage at the single-cell level monitored at submicron resolution by label-free coherent anti-Stokes Raman scattering (CARS) microscopy. While lipid droplet sizes are fairly constant, the number of droplets is a dynamic parameter determined by glucose and ethanol levels. The lowest number of lipid droplets is observed in the transition phase between glucose and ethanol fermentation. It is followed by a buildup during the ethanol phase. The surplus of accumulated lipids is then mobilized at concurrent glucose and ethanol starvation in the subsequent stationary phase. Thus, the highest amount of lipids is found in the ethanol phase, which is about 0.3 fL/cell. Our results indicate that the budding yeast, S. cerevisiae, can be used for the biosynthesis of lipids and demonstrate the strength of CARS microscopy for monitoring the dynamics of lipid metabolism at the single-cell level of importance for optimized lipid production

Thermal Aware Design Automation of the Electronic Control System for Autonomous Vehicles

The autonomous vehicle (AV) technology, due to its tremendous social and economical benefits, is transforming the entire world in the coming decades. However, significant technical challenges still need to be overcome until AVs can be safely, reliably, and massively deployed. Temperature plays a key role in the safety and reliability of an AV, not only because a vehicle is subjected to extreme operating temperatures but also because the increasing computations demand more powerful IC chips, which can lead to higher operating temperature and large thermal gradient. In particular, as the underpinning technology for AV, artificial intelligence (AI) requires substantially increased computation and memory resources, which have been growing exponentially through recent years and further exacerbated the thermal problems. High operating temperature and large thermal gradient can reduce the performance, degrade the reliability, and even cause an IC to fail catastrophically. We believe that dealing with thermal issues must be coupled closely in the design phase of the AVs’ electronic control system (ECS). To this end, first, we study how to map vehicle applications to ECS with heterogeneous architecture to satisfy peak temperature constraints and optimize latency and system-level reliability. We present a mathematical programming model to bound the peak temperature for the ECS. We also develop an approach based on the genetic algorithm to bound the peak temperature under varying execution time scenarios and optimize the system-level reliability of the ECS. We present several computationally efficient techniques for system-level mean-time-to-failure (MTTF) computation, which show several orders-of-magnitude speed-up over the state-of-the-art method. Second, we focus on studying the thermal impacts of AI techniques. Specifically, we study how the thermal impacts for the memory bit flipping can affect the prediction accuracy of a deep neural network (DNN). We develop a neuron-level analytical sensitivity estimation framework to quantify this impact and study its effectiveness with popular DNN architectures. Third, we study the problem of incorporating thermal impacts into mapping the parameters for DNN neurons to memory banks to improve prediction accuracy. Based on our developed sensitivity metric, we develop a bin-packing-based approach to map DNN neuron parameters to memory banks with different temperature profiles. We also study the problem of identifying the optimal temperature profiles for memory systems that can minimize the thermal impacts. We show that the thermal aware mapping of DNN neuron parameters on memory banks can significantly improve the prediction accuracy at a high-temperature range than the thermal ignorant for state-of-the-art DNNs

Spheroidization in tool steels

A carbon steel, W1, and four other alloy tool steels, namely, A2, H13, D3, and M2, were spheroidized by five different procedures. Any modification made in the treatments for an individual steel were suggested by the results obtained with these five procedures. The hardnesses and microstructures obtained were compared with steel samples annealed at a tool steel mill. The response given by different steels to various methods of spheroidization was studied. It was found that A2, W1, and D3 steels responded the best to the cycling method whereas the best response to the isothermal annealing was given by H13 and M2 steels. The effect of neutron irradiation on the spheroidization of W1 steel was studied and it was concluded that the radiation damage in W1 steel did not affect the rate of spheroidization --Abstract, page ii