Polycyclic aromatic hydrocarbons (PAHs) are by-products arising from incomplete combustion. These organic chemicals substances are found almost everywhere and pose a risk to human health because of their potentially h...Polycyclic aromatic hydrocarbons (PAHs) are by-products arising from incomplete combustion. These organic chemicals substances are found almost everywhere and pose a risk to human health because of their potentially hazardous nature and bioavailability in the environment as determined by several regulatory agencies such as US Environmental Protection Agency (US-EPA), US Department of Health and Human Services (DHHS), International Agency for Research on Cancer (IARC) and the National Agency for Food and Drug Administration and Control (NAFDAC). The paper is aimed at studying polycyclic aromatic hydrocarbons in water. The possible sources, chemistry, risk and remediation strategies for polycyclic aromatic hydrocarbons in water have been considered. Studies have shown that exposure to PAHs at levels above the maximum contaminant level for relatively short periods will cause damage to the red blood cells leading to anaemia;suppressed immune system. Long-term exposure to Benzo(a)pyrene at levels above the maximum contaminant level has the potential to cause developmental and reproductive defects as well as cancer. US-EPA, IARC and DHHS has sets a maximum contaminant level (MCL) for benzo(a)pyrene, the most carcinogenic PAH, at 0.0002 mg/L, 0.0001 mg/L for benz(a)anthracene, 0.0002 mg/L for benzo(b)fluoranthene, benzo(k)fluoranthene, and chrysene. 0.0003 mg/L and 0.0004 mg/L have been set for dibenz(a,h)anthracene and indeno (1,2,3-c,d)pyrene respectively. Sustained barn on smoking in public places and burning of word, use of concretes in road construction as against the traditional surfacing of roads using coal tar as well as cars running on compressed natural gas (CNG) or liquefied petroleum gas (LPG) can form part of the preventive strategies.展开更多
Based on recent work, I will give a nontechnical brief review of a powerful quantitative concept in biology, adaptive landscape, ini- tially proposed by S. Wright over 70 years ago, reintroduced by one of the founders...Based on recent work, I will give a nontechnical brief review of a powerful quantitative concept in biology, adaptive landscape, ini- tially proposed by S. Wright over 70 years ago, reintroduced by one of the founders of molecular biology and by others in different bio- logical contexts, but apparently forgotten by modem biologists for many years. Nevertheless, this concept finds an increasingly important role in the development of systems biology and bionetwork dynamics modeling, from phage lambda genetic switch to endogenous net- work for cancer genesis and progression. It is an ideal quantification to describe the robustness and stability of bionetworks. Here, I will first introduce five landmark proposals in biology on this concept, to demonstrate an important common thread in theoretical biology. Then I will discuss a few recent results, focusing on the studies showing theoretical consistency of adaptive landscape. From the perspec- tive of a working scientist and of what is needed logically for a dynamical theory when confronting empirical data, the adaptive landscape is useful both metaphorically and quantitatively, and has captured an essential aspect of biological dynamical processes. Though at the theoretical level the adaptive landscape must exist and it can be used across hierarchical boundaries in biology, many associated issues are indeed vague in their initial formulations and their quantitative realizations are not easy, and are good research topics for quantitative biologists. I will discuss three types of open problems associated with the adaptive landscape in a broader perspective.展开更多
文摘Polycyclic aromatic hydrocarbons (PAHs) are by-products arising from incomplete combustion. These organic chemicals substances are found almost everywhere and pose a risk to human health because of their potentially hazardous nature and bioavailability in the environment as determined by several regulatory agencies such as US Environmental Protection Agency (US-EPA), US Department of Health and Human Services (DHHS), International Agency for Research on Cancer (IARC) and the National Agency for Food and Drug Administration and Control (NAFDAC). The paper is aimed at studying polycyclic aromatic hydrocarbons in water. The possible sources, chemistry, risk and remediation strategies for polycyclic aromatic hydrocarbons in water have been considered. Studies have shown that exposure to PAHs at levels above the maximum contaminant level for relatively short periods will cause damage to the red blood cells leading to anaemia;suppressed immune system. Long-term exposure to Benzo(a)pyrene at levels above the maximum contaminant level has the potential to cause developmental and reproductive defects as well as cancer. US-EPA, IARC and DHHS has sets a maximum contaminant level (MCL) for benzo(a)pyrene, the most carcinogenic PAH, at 0.0002 mg/L, 0.0001 mg/L for benz(a)anthracene, 0.0002 mg/L for benzo(b)fluoranthene, benzo(k)fluoranthene, and chrysene. 0.0003 mg/L and 0.0004 mg/L have been set for dibenz(a,h)anthracene and indeno (1,2,3-c,d)pyrene respectively. Sustained barn on smoking in public places and burning of word, use of concretes in road construction as against the traditional surfacing of roads using coal tar as well as cars running on compressed natural gas (CNG) or liquefied petroleum gas (LPG) can form part of the preventive strategies.
基金supported in part by a grant from USA National Institutes of Health (No. K25-HG002894-05)985 Project from Shanghai Jiao Tong University.
文摘Based on recent work, I will give a nontechnical brief review of a powerful quantitative concept in biology, adaptive landscape, ini- tially proposed by S. Wright over 70 years ago, reintroduced by one of the founders of molecular biology and by others in different bio- logical contexts, but apparently forgotten by modem biologists for many years. Nevertheless, this concept finds an increasingly important role in the development of systems biology and bionetwork dynamics modeling, from phage lambda genetic switch to endogenous net- work for cancer genesis and progression. It is an ideal quantification to describe the robustness and stability of bionetworks. Here, I will first introduce five landmark proposals in biology on this concept, to demonstrate an important common thread in theoretical biology. Then I will discuss a few recent results, focusing on the studies showing theoretical consistency of adaptive landscape. From the perspec- tive of a working scientist and of what is needed logically for a dynamical theory when confronting empirical data, the adaptive landscape is useful both metaphorically and quantitatively, and has captured an essential aspect of biological dynamical processes. Though at the theoretical level the adaptive landscape must exist and it can be used across hierarchical boundaries in biology, many associated issues are indeed vague in their initial formulations and their quantitative realizations are not easy, and are good research topics for quantitative biologists. I will discuss three types of open problems associated with the adaptive landscape in a broader perspective.
