As one of its primary physiological functions, sPLA(2)-IIA appears to act as an antibacterial agent. In particular, sPLA(2)-IIA shows high activity towards Gram-positive bacteria such as Staphylococcus aureus (S. aureus). This antibacterial activity results from the preference of the enzyme towards membranes enriched in anionic lipids, which is a common feature of bacterial membranes. An intriguing aspect observed in a variety of bacterial membranes is the presence of a broad but cooperative lipid chain melting event where the lipids in the membrane transition from a solid-ordered (so) into a liquid-disordered (ld) state close to physiological temperatures. It is known that the enzyme is sensitive to the level of lipid packing, which changes sharply between the so and the ld states. Therefore, it would be expected that the enzyme activity is regulated by the bacterial membrane thermotropic behavior. We determine by FTIR the thermotropic lipid chain melting behavior of S. aureus and find that the activity of sPLA(2)-IIA drops sharply in the so state. The activity of the enzyme is also evaluated in terms of its effects on cell viability, showing that cell survival increases when the bacterial membrane is in the so state during enzyme exposure. These results point to a mechanism by which bacteria can develop increased resistance towards antibacterial agents that act on the membrane through a cooperative increase in the order of the lipid chains. These results show that the physical behavior of the bacterial membrane can play an important role in regulating physiological function in an in vivo system.
We compute the average work done by an external agent, driving a piston at constant speed, over a single particle gas going through an adiabatic compression and expansion process. To do so, we get the analytical expression relating the number of collisions between the piston and the particle with the position of the piston during the process. The ergodicity breaking of the system during the process is identified as the source of its irreversibility. In addition, we observe that by using particular initial distributions for the state of the particle, it is possible to preclude the possibility of a net energy transfer from the agent to the particle during the process.
En Colombia, como en el resto del mundo, la disrupción generada por la pandemia global por la COVID-19 creó una nueva realidad que normalizó y generalizó el uso de tecnologías de información y comunicación (tic), redefiniendo el concepto de presencialidad. Utilizando las 415 respuestas de una encuesta realizada, este estudio presenta una descripción de los efectos de moderación por sexo y por generación (Z, Y, X, W) sobre la percepción en el uso de tecnologías digitales en el ámbito de la educación superior. Esta investigación encontró que no existe brecha por sexo, es decir que la percepción de mujeres y hombres es similar, y que los comportamientos de percepción esperados para menores de 25 años son estadísticamente similares a los de los encuestados mayores de 65 años.
Increases in business performance are essential for an organization's success in both the public and private sectors. Using the Hofstede organizational culture model, the chapter has centered emphasis on factors that affect primarily financial results. In this study, the authors look at the importance of organizational culture traits as a predictor of financial performance in Colombian and Ecuadorian companies. They discovered that despite Colombia and Ecuador having similar histories and cultures that can be similar to a high level, in volatile and rapidly evolving settings, strategic approaches that concentrate on both distinction and low costs at the same time are often in conflict with Porter's classic approach.
Competitiveness is essential for an organization's success in both the public and private sectors. Using three well-known mathematical methodologies, this work has centered its analysis on factors that affect primarily organizational competitiveness viewed through three different scales (global, local, and businesses). Using these methods, researchers and decision-makers gain insight to perform a qualitative analysis over key metrics of each level looking for improvements in business competitive performance and elucidate the importance of intangible assets like strategy. The authors identified that although each tool can only let us know some aspects about system agents, after combining the three tools as a toolbox, it might be used in volatile and rapidly evolving settings when strategic approaches concentrate on accurate resource allocation that demands a lot of time.
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