When cells are exposed to adverse conditions they go through a process called what?

11.8 Effect of Lubrication

Good bearing lubrication can reduce the effects of adverse conditions such as a bad surface finish or a certain amount of debris, but even the best oil on the market cannot make a starving bearing survive. The design and position of oil circulation grooves are critical. These channels should neither have sharp edges, which act as oil wipers, nor be located in a high-pressure area of the bearing. Some bearing designs use oil channels in the high-pressure area as a resource to control the pressure distribution of the oil film or correct the dynamic behavior of the bearing.

Some causes of inadequate lubrication are machine startup without prelubrication, insufficient clearance, low oil flow to the bearing, and defects in the lube oil pump or system.

5.4.7 Coconut oil crops

Different species of coconut (Cocos nucifera) live in adverse conditions. Coconut oil is a primary source of basic oleochemicals (soaps, lubricants, plasticisers, surfactants, detergents) [97]. Coconut oil is the main crop in the Philippines (1.25–1.75 Mt/yr), which intends developing coconut biodiesel (a pilot plant was already operational in 1995); see also Sections 14.3 and 14.3.1. Coconut and palm oil production in South-East Asia is frequently hit by weather-related problems, such as typhoons.

Biodiesel from the two lauric oils, originating from coconut and palm fruit kernel (E. guineensis), which both contain high contents of C12:0 (approximately 50%) and saturated short-chain fatty acids (~85–90%), are characterised by an excellent cetane number but poor cold-temperature properties (relevant only to temperate climates) [98]. Coconut oil generates more glycerol (13.5%) than most other oils and fats (from 9 to 12%). The coconut biodiesel life cycle system is shown in Fig. 14.4.

Epigenetic effects of prenatal conditions

Two studies assessed the epigenetic effects of prenatal exposure to adverse conditions in preterm infants (Liu et al., 2012; Vidal et al., 2014). Liu et al. (2012) research enrolled infants from depressed and non-depressed mothers, assessing DNA methylation at imprinted genes. Infants from mothers characterized by severe depressed mood (i.e., history of depression plus depression in pregnancy) had higher methylation of MEG3 gene—whose regions have been identified and hypothesized to affect growth and development in both the placenta and the fetus (Kagami et al., 2010; Skaar et al., 2012)—and this difference was grater within female infants as well as in infants from black women. No differences in MEG3 methylation emerged among mothers with or without severe depression as well as those with or without a preterm infant. Compared to normal birth weight infants, low-birth weight infants had 1.6% lower IGF2 methylation and 5.9% lower methylation at the PLAGL1 gene. Similarly, Vidal et al. (2014) reported increased methylation of the MEST gene in preterm infants exposed to maternal stress during pregnancy compared to controls from mothers without significant depressive symptoms before delivery. Despite maternal stress was not found to be associated with heightened risk of preterm birth, infants from mothers who reported higher stress during pregnancy had 2.8% increase in DNA methylation of the MEST gene, compared to control infants (Vidal et al., 2014). This effect was more robust in females, compared to male infants. The MEST gene is involved in the metabolism pathways that affect growth and maintenance of mesodermal cells (Kobayashi et al., 1997). Recent studies on animal models suggest that this gene is up-regulated in offspring exposed to stress (Takahashi, Kamei, & Ezaki, 2005).

Taken together, these findings extend previous evidence on full-term infants to preterm ones, suggesting that early exposure to adverse events during the third trimester of pregnancy is capable to alter the epigenetic status of imprinted and placenta-related genes that have relevant implications for fetal development.

16.12 Discussion

Deliberations on the resiliency of cities and communities under various adverse conditions are a recent phenomenon, and the approaches for addressing it through development policies are being explored. This chapter puts forth an attempt to orient the decision making for urban infrastructures from a sociological perspective. The analysis based on a community’s evaluation brought out the fact that vulnerable communities in cities not only exist in the slums but that citizens at large are exposed to various levels of vulnerabilities owing to the conditions of urban infrastructures and the physical development.

However, the study noted a limitated literature available on community resilience with a focus on urban infrastructures, and those available mostly provide theoretical construes. Studies on resilient infrastructures focus on improving engineering capacities and levels for resiliency. Some other estimation methods on resiliency available in literature, such as CDRI, consider the positions of local urban governments and do not accommodate the perception of resiliency of local community. The present study, therefore, is unique in a way as it tries to integrate the evaluations of the local community about the access and availability of basic life support services and infrastructures for evaluating levels of resiliency.

Risks are generated within cities and are reflected through rising urban population, accumulation of economic and physical assets, highly pressurized infrastructures, developments in hazardous areas, and rising urban poor. It is commonly observed through various case studies that the failure of conventional tools of urban planning such as land use distributions and development control regulations are giving rise to newer urban risks. The proposed framework in this research for prioritizing areas and actions for achieving resiliency can potentially give directions to use these conventional tools effectively and generate resiliency in urban communities.

The cities in India are undergoing tremendous transformations owing to the rapid social, economical, and environmental transitions. Approaches for managing urban growth are yet dominated by the top-to-bottom approach, the success of which is being questioned due to rising urban issues. While efforts to develop a bottom-up approach are also being taken in managing urban environments, a similar approach is absent in managing urban infrastructures. The alternative framework for achieving disaster risk resiliency developed in this research using community’s evaluation demonstrates the possibility of evolving such a bottom-up approach in planning and managing local resources and infrastructures in urban areas.

5.6.1 Reliability

MEMS-based optical switches must be able to function in adverse conditions, as well as over an extended period of time. The fact that there are mechanical moving parts inside the switch makes reliability a bigger concern in MEMS than in traditional solutions such as integrated circuits. As mentioned in section 5.4, the relationship between mirror displacement and driving voltage could change due to factors such as temperature and aging. The closed-loop approach helps combat that problem. The change, if any, in the switching performance after millions of switching cycles also needs to be studied. In order to gain wide acceptance in optical networks, the reliability and repeatability of MEMS optical switches must be well researched and understood.

APPLICATIONS

These cells are frequently used where their extremely low deterioration rate under adverse conditions is advantageous. Examples include rescue radio receivers, emergency alarm devices, etc. If stored at between 50°F and 70°F in dry conditions, there will be negligible deterioration after 2 years.

In medical electronics, rocketry and miniaturised communications equipment, these cells find common use. They will withstand mechanical shock and corrosion. Effects of high pressure and vacuum have negligible effect on their operation and unlike most other primary cells they will deliver their designed output continuously without requiring recuperation periods.

Their stability is such that Mallory mercury cells have gained wide acceptance of their use as secondary standards of voltage reference.

When cells are exposed to adverse conditions they go through a process called?

What are the 4 types of cellular adaptation?

What specifically happens to a cell during the process of apoptosis?

What is cellular adaptation to injury?