Enzyme activity in terrestrial soil in relation to exploration of the Martian surface

Urease activity in soil is persistent for long periods under low water, low temperature, and sterile regimes, and it was suggested that some form of enzyme-protective mechanism exists in soil. Dublin soil was extracted by sonication in water followed by adding a mixture of salts. Urease activity is associated with the organo-mineral complex thus obtained and is resistant to the activities of proteolytic enzymes. Clay free soil organic matter prepared subsequently by filtration also exhibits urease activity which is resistant to proteolysis. Models consisting of enzymes with bentonite and lignin were found to mimic this resistance to proteolysis. A model system is presented which suggests both the origin and location of soil ureases and a reason for their persistence in nature

Immersed Boundary Method for the Solution of 2D Inviscid Compressible Flow Using Finite Volume Approach on Moving Cartesian Grid

In this study, two-dimensional inviscid compressible flow is solved around a moving solid body using Immersed Boundary Method (IBM) on a Cartesian grid. Translational motion is handled with a Cartesian grid generated around the body which moves with body on a background grid. In IBM, boundaries are immersed within the grid points. In this paper solution domain is discretized using finite volume approach. To implement boundary conditions on immersed boundaries, a set of Ghost finite volumes are defined along the wall boundaries. Boundary conditions are used to assign flow variables on these Ghost finite volumes. Governing equations are solved using dual time step method of Jameson. Finally, numerical results obtained from the present study are compared with the other numerical results to evaluate the correct performance of the present algorithm and its accuracy

Alpha/Beta Interferon Receptor Signaling Amplifies Early Proinflammatory Cytokine Production in the Lung during Respiratory Syncytial Virus Infection

Type I interferons (IFNs) are produced early upon virus infection and signal through the alpha/beta interferon (IFN-α/β) receptor (IFNAR) to induce genes that encode proteins important for limiting viral replication and directing immune responses. To investigate the extent to which type I IFNs play a role in the local regulation of inflammation in the airways, we examined their importance in early lung responses to infection with respiratory syncytial virus (RSV). IFNAR1-deficient (IFNAR1−/−) mice displayed increased lung viral load and weight loss during RSV infection. As expected, expression of IFN-inducible genes was markedly reduced in the lungs of IFNAR1−/− mice. Surprisingly, we found that the levels of proinflammatory cytokines and chemokines in the lungs of RSV-infected mice were also greatly reduced in the absence of IFNAR signaling. Furthermore, low levels of proinflammatory cytokines were also detected in the lungs of IFNAR1−/− mice challenged with noninfectious innate immune stimuli such as selected Toll-like receptor (TLR) agonists. Finally, recombinant IFN-α was sufficient to potentiate the production of inflammatory mediators in the lungs of wild-type mice challenged with innate immune stimuli. Thus, in addition to its well-known role in antiviral resistance, type I IFN receptor signaling acts as a central driver of early proinflammatory responses in the lung. Inhibiting the effects of type I IFNs may therefore be useful in dampening inflammation in lung diseases characterized by enhanced inflammatory cytokine production

Space and social distancing in managing and preventing COVID-19 community spread: An overview.

The spread of COVID-19 at a large scale and at a rapid pace indicates the lack of social distancing measures at multiple levels. The individuals are not to be blamed, nor should we assume the early measures were ineffective or not implemented. It is all down to the multiplicity of transmission factors that made the situation more complicated than initially anticipated. Therefore, in facing the COVID-19 pandemic, this overview paper discusses the importance of space in social distancing measures. The methods used to investigate this study are literature review and case study. Many scholarly works have already provided us with evidence-based models that suggest the influential role of social distancing measures in preventing COVID-19 community spread. To further elaborate on this important topic, the aim here is to look at the role of space not only at the individual level but at larger scales of communities, cities, regions, etc. The analysis helps better management of cities during the pandemics such as COVID-19. By reflecting on some of the ongoing research on social distancing, the study concludes with the role of space at multiple scales and how it is central to the practice of social distancing. We need to be more reflective and responsive to achieve earlier control and containment of the disease and the outbreak at the macro level. [Abstract copyright: © 2023 Published by Elsevier Ltd.

Multiwall Carbon Nanotubes Modified Carbon Paste Electrode for Determination of Copper(II) by Potentiometric and Impedimetric Methods

Abstract A chemically modified carbon paste electrode with multiwall carbon nanotube (MWCNT) was prepared and used as a sensor for Cu 2+ ion. The unique chemical and physical properties of CNT have paved the way to new and improved sensing devices. A central composite chemometrics design was applied for multivariate optimization of the effects of three significant parameters (Graphite powder (X 1 ), MWCNT (X 2 ) and Ionophre (X 3 )) influencing the response of the electrode. In the optimized conditions, the electrode exhibits a Nernstian slope of 30.1 mV/decade in a linear range between 1.0×10 -6 to1.0×10 -1 M over a wide pH range (2.0-6.5). Importantly, the effect of the MWCNT on the performance of electrode was investigated by impedance technique, that showed the MWCNT helps the transduction of the signal in carbon paste electrode and the charged transfer resistance (R ct ) was reduced. The impedimetric results indicated that the linear concentrations range was 1.0×10 −7 to 1.0×10 −1 M and in comparison with potentiometry, the pH range increased to 2.0−7.5. JNS All rights reserve

Parenting practices and adolescent eating behaviors in African American families.

Parents play an important role in developing the eating behaviors of their children by adopting specific parenting practices. As the prevalence of obesity is high amongst African American adolescents, investigations into associations of specific parenting practices and adolescents' eating behaviors are essential. In this exploratory study, 14 African American parent-adolescent dyads were interviewed to characterize the influence of eight different parenting practices on the consumption of three main food categories (dairy, fruits and vegetables, and unhealthy snacks). The results revealed that authoritarian parenting practices were correlated with a higher BMI percentile in adolescents, whereas modeling and monitoring are correlated with a higher parent BMI. In addition, reasoning, monitoring, modeling, and authoritative parenting practices were associated with less unhealthy snack consumption among adolescents. Reasoning and monitoring were the only parenting practices associated with higher fruit and vegetable consumption. Finally, a significant correlation was found between eating fruits and vegetables and unhealthy snacks and the location of eating. In conclusion, different parenting practices and environmental factors may impact BMI and food consumption of African American dyads. The results of this study can be used to guide improvement in, and/or development of, nutritional education interventions considering the cultural differences of racial minorities

Dramatic rise in cesarean birth in Iran: A coalition of private medical practices and women�s choices

Objectives: Cesarean delivery without medical indication has regularly increased among Iranian women in the last three decades, and Iran has one of the highest rates of cesarean in the world. The present study aimed at reviewing the studies regarding the increase of cesarean in Iran and discussing the root causes for such an increase. Methods: This literature review focused on the existing quantitative and qualitative studies conducted from January 1990 to January 2019 regarding the reasons for an increase in the cesarean section in Iran. The combination of keywords including �cesarean section�, �C-section�, �cesarean delivery�, and �Iran� was searched in several databases such as MEDLINE/PubMed, Embase, ISI Web of Science and Scopus, along with national databases (e.g., SID, MagIran, Iran Medex, and IranDoc). Results: A dramatic rise in cesarean birth stems from a number of factors including the role of health care professionals, insurance companies, socio-cultural factors, and the health policies, all of which have their roots in the medicalization of birth. Conclusions: In general, reducing the cesarean on maternal request necessitates the de-medicalization of birth, cultural awareness through the mass media, informing women of the long-term complications of cesarean, and physical and mental preparation of the mother. In addition, other contributing factors include encouraging inter-professional teamwork and collaboration between midwives and obstetrician-gynecologists, transforming the current curriculum of the midwifery and residency education, applying the midwifery-led care models, and decreasing the fear of litigation in midwifery and obstetrics-gynecology. Otherwise, maternal and fetal mortality will rise in the near future due to increased complications in subsequent pregnancies. © 2020 The Author(s)

Relationship between family racial/ethnic backgrounds, parenting practices and styles, and adolescent eating behaviors.

Obesity is more prevalent among racial minority children in the United States, as compared to White children. Parenting practices can impact the development of children's eating behaviors and habits. In this study, we investigated the relationships among racial/ethnic backgrounds, parenting practices and styles, and eating behaviors in adolescents. Fifty-one parent-adolescent dyads were interviewed to characterize parenting practices and styles, as well as the consumption of dairy, fruits and vegetables, and unhealthy snacks. Height and weight were measured to calculate parent BMI and adolescent BMI-for-age percentiles. Three parenting practice categories-modeling, authoritative, and authoritarian-were found to be related to race/ethnicity. A higher score in authoritarian parenting practices was related to higher BMI percentiles among African American adolescents, whereas a higher score in monitoring practices was related to lower BMI percentiles among non-Hispanic White adolescents. Modeling, reasoning, and monitoring led to higher consumption of fruits and vegetables among adolescents; however, the consumption of unhealthy snacks was higher with rule-setting and lower with reasoning and authoritative practices. Finally, an analysis of the relationships between environmental factors and snack intake showed that adolescents consumed significantly more unhealthy snacks when performing other activities while eating. In conclusion, the findings from this study suggest that families' racial heritages are related to their parenting practices, BMI percentiles, and their adolescents' food consumption and eating behaviors. The results of this study can be used to develop and improve adolescent nutrition education and interventions with consideration of their racial/ethnic backgrounds