No abstract

A simple Mite Population Index (MPI) model is presented which predicts the effect on house dust mite populations of any combination of temperature and relative humidity (RH). For each combination, the output is an index, or multiplication factor, such that 1.1 indicates 10% population growth and 0.9 indicates 10% population decline. To provide data for the model, laboratory experiments have been carried out using lab cultures of Dermatophagoides pteronyssinus. The population change was observed for mites held in steady-state conditions at different combinations of temperature and RH over 21 days. From the results, a best-fit equation has been derived which forms the basis of the MPI model. The results also enable a new term to be defined: the Population Equilibrium Humidity, PEH, the RH for a given temperature at which house dust mite populations neither grow nor decline. It is similar to Critical Equilibrium Humidity, the RH below which house dust mites are unable to maintain water balance, but relates to a population of mites (rather than a physiological phenomenon) and is more able to take account of the observed effects of extremes of temperature and RH. Compared with previous population models, the MPI model is potentially more accurate and comprehensive. It can be combined with other simple models (described in previous papers), such as BED, which simulates the average hygrothermal conditions in a bed, given room conditions, and Condensation Targeter II, which simulates room conditions given a range of easily obtainable inputs for climate, house type and occupant characteristics. In this way it is now possible, for any individual dwelling, to assess the most effective means of controlling mite populations by environmental means, such as by improving standards of ventilation and insulation, or by modifying the occupant behaviour that affects the hygrothermal environment within a dwelling. Although the MPI model requires further development and validation, it has already proved useful for understanding more clearly how the different hygrothermal conditions found in beds and bedrooms can affect mite populations. It has also demonstrated that there is considerable scope for controlling mites by environmental means in cold winter climates such as the UK.

La diffusion très étendue de la poterie caractéristique associée au phénomène de l’Early Transcaucasian Culture (connue sous les noms de cultures ETC, Kura-Araxe, Yanik, Karaz et Khirbet Kerak) a longtemps constitué une énigme complexe pour les archéologues. Ce problème a suscité des explications variées, fondées sur trois thèmes principaux – migration, nomadisme ou métallurgie –, chaque génération mettant au point un scénario précis qui corresponde aux paradigmes en cours. Cet article examine la relation « systémique-structurelle » à grande échelle entre le phénomène ETC et ses voisins, en comparant les traditions culinaires, les modes idiosyncratiques de production artisanale (avec des indications sur l’artisanat et sur les échanges) et l’organisation de l’espace. Les résultats mettent en évidence les traits qui font de l’ETC un phénomène particulier et nous permettent de proposer un scénario expérimental qui concourt à expliquer à la fois sa longévité et ses phases d’expansion et de contraction.

A major global effort is currently ongoing to search for therapeutics and vaccines to treat or prevent infection by the SARS-CoV-2 virus. Repurposing existing entities is one attractive approach. The heparan sulfate mimetic pixatimod is a clinical-stage synthetic sulfated compound that is a potent inhibitor of the glycosidase heparanase, and has known anti-cancer, anti-inflammatory and also antiviral properties. Here we show that pixatimod binds directly to the SARS-CoV-2 spike protein S1 receptor binding domain (RBD) and alters its conformation. Notably, this site overlaps with the known ACE2 binding site in the S1 RBD. We find that pixatimod inhibits binding of recombinant S1 RBD to Vero cells which express the ACE2 receptor. Moreover, in assays with three different isolates of live SARS-CoV-2 virus we show that pixatimod effectively inhibits viral infection of Vero cells. Importantly, its potency is well within its safe therapeutic dose range. These data provide evidence that pixatimod is a potent antiviral agent against SARS-CoV-2. Together with its other known activities this provides a strong rationale for its clinical investigation as a new multimodal therapeutic for the current COVID-19 pandemic.