抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(12)61766-8.pdf

A comparative risk assessment of burden of disease and injury attributable to 67 risk factors and risk factor clusters in 21 regions, 1990-2010: a systematic analysis for the Global Burden of Disease Study 2010

Identifying and quantifying planetary boundaries that must not be transgressed could help prevent human activities from causing unacceptable environmental change, argue Johan Rockstrom and colleagues.

/pdf/a-safe-operating-space-for-humanity-tynyc6i2kf.pdf

A safe operating space for humanity

Human alteration of Earth is substantial and growing. Between one-third and one-half of the land surface has been transformed by human action; the carbon dioxide concentration in the atmosphere has increased by nearly 30 percent since the beginning of the Industrial Revolution; more atmospheric nitrogen is fixed by humanity than by all natural terrestrial sources combined; more than half of all accessible surface fresh water is put to use by humanity; and about one-quarter of the bird species on Earth have been driven to extinction. By these and other standards, it is clear that we live on a human-dominated planet.

/pdf/human-domination-of-earth-s-ecosystems-5eevmqq987.pdf

Human Domination of Earth's Ecosystems

This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.

/pdf/the-hitran-2008-molecular-spectroscopic-database-1ud8clpej3.pdf

The HITRAN 2008 molecular spectroscopic database

Most continental environments (e.g., soils, freshwaters) are naturally acidic (pH<7) due to respiration and oxidation reactions in biotic and abiotic systems. In the last 100 years, the acidity of many regions of the world has increased as a consequence of energy and food production. In the last 30 years, the phenomena and impacts of 'acid rain' have been extensively investigated in Europe, North America and Asia. This paper will give a brief historical overview of acid deposition, the impact that food and energy production have had on enhancing the acidity of the environment, and the important role that the International Conferences have had in advancing our understanding of acid rain and its effects. The paper will conclude a look towards the future.

Acidification of the World: Natural and Anthropogenic

Organic nitrogen in precipitation at the mid-Atlantic U.S. Coast—methods evaluation and preliminary measurements

Sediment cores were collected from Woodhull Lake (Adirondack State Park, New York) in July 1975. Of 44 metals analyzed by neutron activation and atomic absorption spectrophotometry, 9 (Ag, Au, Cd, Cr, Cu, Pb, Sb, V, and Zn) showed increased rates of deposition in the last 30 years. These increases are attributed to increased rates of atmospheric deposition. Similar results were obtained from cores of Honnedaga Lake (Adirondack State Park, New York) and Lake of the Clouds (Mt. Washington, New Hampshire).

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.1979.24.3.0427

Atmospheric enhancement of metal deposition in Adirondack lake sediments1

Atmospheric sampling was conducted aboard R/V Polar Duke from March 21 to April 27, 1986, in the southern Drake Passage and in the coastal waters west of the Antarctic Peninsula. Average atmospheric concentrations (n = 6) of sulfur dioxide (SO2) vapor, aerosol methanesulfonate (CH3SO3−), and aerosol non-sea-salt sulfate (nss−SO4=) were 0.36, 0.22, and 0.34 nmol m−3, respectively. Cascade impactor data indicated that more than 85% of the masses of both CH3SO3− and nss−SO4= were on particles of <0.25-μm mean aerodynamic radius. Average concentrations (n = 8) of CH3SO3− and nss−SO4= in precipitation were 0.09 and 0.57 μM, respectively. Box model calculations based on this limited data suggest a total sulfur removal rate from the local marine boundary layer of 0.3–7.2 μmol m−2 day−1. This removal approximately balances the oceanic source of dimethylsulfide (DMS) sulfur of 1.2–4.4 μmol m−2 day−1 (±100%) estimated by Berresheim [1987] from data obtained during the same cruise. The box model calculations also suggest that heterogeneous SO2 oxidation may be the major pathway for DMS to sulfate conversion (∼75%) and/or that other sources of sulfate may not be negligible. Observed mineral aerosol and 222Rn concentrations were low but slightly elevated above “pure” remote marine background levels, suggesting a weak but discernible continental character in sampled air. Uncertainties are large owing to the limited sampling time, study area, and numbers of samples obtained, but overall, the sulfur cycle in the coastal Antarctic marine boundary layer appears not to differ remarkably from that in other remote marine regions.

James N. Galloway

Papers

Acidification of the World: Natural and Anthropogenic

Organic nitrogen in precipitation at the mid-Atlantic U.S. Coast—methods evaluation and preliminary measurements

Atmospheric enhancement of metal deposition in Adirondack lake sediments1

A study of the sulfur cycle in the Antarctic marine boundary layer

Bacterial utilization of formic and acetic acid in rainwater