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.

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The HITRAN 2008 molecular spectroscopic database

Changes in Atmospheric Constituents and in Radiative Forcing

An improved method for computing potential-derived charges is described which is based upon the CHELP program available from QCPE.1 This approach (CHELPG) is shown to be considerably less dependent upon molecular orientation than the original CHELP program. In the second part of this work, the CHELPG point selection algorithm was used to analyze the changes in the potential-derived charges in formamide during rotation about the CN bond. In order to achieve a level of rotational invariance less than 10% of the magnitude of the electronic effects studied, an equally-spaced array of points 0.3 A apart was required. Points found to be greater than 2.8 A from any nucleus were eliminated, along with all points contained within the defined VDW distances from each of the atoms. The results are compared to those obtained by using CHELP. Even when large numbers of points (ca. 3000) were sampled using the CHELP selection routine, the results did not indicate a satisfactory level of rotatational invariance. On the basis of these results, the original CHELP program was found to be inadequate for analyzing internal rotations.

Determining atom-centered monopoles from molecular electrostatic potentials. The need for high sampling density in formamide conformational analysis

Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

/pdf/the-formation-properties-and-impact-of-secondary-organic-4x4th6v9ke.pdf

The formation, properties and impact of secondary organic aerosol: current and emerging issues

The present paper reviews existing knowledge with regard to Organic Aerosol (OA) of importance for global climate modelling and defines critical gaps needed to reduce the involved uncertainties. All pieces required for the representation of OA in a global climate model are sketched out with special attention to Secondary Organic Aerosol (SOA): The emission estimates of primary carbonaceous particles and SOA precursor gases are summarized. The up-to-date understanding of the chemical formation and transformation of condensable organic material is outlined. Knowledge on the hygroscopicity of OA and measurements of optical properties of the organic aerosol constituents are summarized. The mechanisms of interactions of OA with clouds and dry and wet removal processes parameterisations in global models are outlined. This information is synthesized to provide a continuous analysis of the flow from the emitted material to the atmosphere up to the point of the climate impact of the produced organic aerosol. The sources of uncertainties at each step of this process are highlighted as areas that require further studies.

/pdf/organic-aerosol-and-global-climate-modelling-a-review-4ojfzx6x50.pdf

Organic aerosol and global climate modelling: a review

Nematode worms are important. Many parasitic species infest plants, animals and insects, whilst their free-living cousins decompose plant and animal materials in terrestrial soils and marine sediments. But they have been notoriously difficult to classify, phylogenetically speaking, because they have few distinguishing characteristics. By analysing the sequences of small-subunit ribosomal DNA from 53 species, however, this has now been done. Not least, the new findings provide clues about the evolution of parasitism.

Systematics: Sequences lead to tree of worms

An 5-ethyl-2-thiouracil derivative with a 6-(tetrahydronaphthalen-1-yl)methyl substituent was synthesized by condensation of thiourea with an adequate β-ketoester which in turn was synthesized in a single step from (tetrahydronaphthalen-1-yl)acetonitrile. The latter starting material was also used to synthesize an analogously substituted tetrahydronaphthalen-1-yl substituted uracil with a locked conformation. Only the non-nucleoside derivatives prepared from the desulfurized substituted 2-thiouracil showed moderate activity against HIV whereas a corresponding non-nucleoside derivative was devoid of activity against HIV.

New Emivirine (MKC-442) Analogues Containing a Tetrahydronaphthalene at C-6 and their Anti-HIV Activity

A Sampling Line Artifact in Stack Emission Measurement of Alkanolamine-enabled Carbon Capture Facility: Surface Reaction of Amines with Formaldehyde

A systematic approach that identifies 11 new mutations as indicators of transmission of resistance

The nucleoside analogue azidothymidine (AZT) and the methyl ester of amphotericin B (AME) were assayed for antiviral effect on HIV infection singly and in combination. Both compounds were effective in inhibiting HIV infection of MT-4 cells. At concentrations where either compound alone had no significant effect on infection, the compounds in combination were potent inhibitors of HIV as evaluated by reduction in HIV antigen production and HIV induced cytopathic effect. These results indicate that a combination therapy employing compounds with different modes of action like AZT and AME may have synergistic antiviral properties. Amphotericin B itself significantly reduced HIV infectivity in vitro and should not be used as an antifungal agent in cultures intended to propagate HIV.

Claus J. Nielsen

Papers

Systematics: Sequences lead to tree of worms

New Emivirine (MKC-442) Analogues Containing a Tetrahydronaphthalene at C-6 and their Anti-HIV Activity

A Sampling Line Artifact in Stack Emission Measurement of Alkanolamine-enabled Carbon Capture Facility: Surface Reaction of Amines with Formaldehyde

A systematic approach that identifies 11 new mutations as indicators of transmission of resistance

Synergistic antiviral effect in vitro of azidothymidine and amphotericin B methyl ester in combination on HIV infection.