Continuous atmospheric in-situ measurements of the CH4/CO ratio at the Mt. Cimone station (Italy, 2165 m a.s.l.) and their possible use for estimating regional CH4 emissions

Methane (CH₄) is an important climate forcer, contributing about 17% of the total radiative forcing by long living greenhouse gases. The Po basin is one of the most polluted and densely populated areas in Europe representing an important source region for CH₄. The aim of this work was to test an inter-species correlation approach to derive estimates of anthropogenic CH₄ emissions for the period 2015-2019 from the Po basin by combining CO bottom-up inventory data and continuous CH₄ and CO observations from a mountain site in the northern Italy. The tested methodology suggested lower emissions in respect to EDGAR (-17%) and the Italian National Inventory (-40%) for the Po basin. However, despite the two bottom-up inventories, the emissions derived from the atmospheric observations reported an increasing tendency from 2015 to 2019 for the CH₄ emissions. A sensitivity study revealed that using different subsets of the atmospheric observations implied a difference of 26% in the CH₄ emission estimates. The highest agreement with two bottom-up CH₄ inventories (EDGAR and the Italian national inventory) were obtained when atmospheric data were strictly selected for periods representative of air mass transport from the Po basin. Our study identified various challenges when using this methodology as a benchmark to verify bottom-up CH₄ inventories. Issues could be attributed to the annual aggregation of the proxies used to derive the emission amounts, to the CO bottom-up inventory used as input information and to the relatively high sensitivity of the results to the different subsets of the atmospheric observations. However, the use of different bottom-up inventories as input data for CO emissions can potentially provide information that should be carefully considered for the purpose of integrating CH₄ bottom-up inventories.

Characteristics and Publication Rates for Podium Presentations at National Hand Surgery Meetings from 2007 to 2012

The purpose of this study was to evaluate and compare the research presented at the annual meetings of the American Society for Surgery of the Hand (ASSH) and the American Association for Hand Surgery (AAHS). Podium presentation data were extracted from the abstract books of the annual meetings of the ASSH and AAHS from 2007 to 2012. Corresponding publications were identified using searchable online publication databases and an algorithm linking authorship and content. The majority of research was clinical and the most common topics were trauma, degenerative conditions, and biomechanics. The most common body region of interest was the wrist/forearm. ASSH podium presentations were of a stronger level of evidence and were more likely to be published. The mean times to publication for research presented at the ASSH and AAHS meetings were 16.7 and 16.4 months, respectively. Presentations from each society were subsequently published at higher proportions in their affiliated journals. Furthermore, in comparison to AAHS presentations, a significantly larger proportion of research presented at the ASSH meetings was published in the Journal of Bone and Joint Surgery , while a larger proportion of AAHS presentations were published in Plastic and Reconstructive Surgery and Microsurgery .

Molecular model of the contractile ring

We present a model for the actin contractile ring of adherent animal cells. The model suggests that the actin concentration within the ring and consequently the power that the ring exerts both increase during contraction. We demonstrate the crucial role of actin polymerization and depolymerization throughout cytokinesis, and the dominance of viscous dissipation in the dynamics. The physical origin of two phases in cytokinesis dynamics ("biphasic cytokinesis") follows from a limitation on the actin density. The model is consistent with a wide range of measurements of the midzone of dividing animal cells.

The effect of alpha-actinin on the length distribution of F-actin

Actin filament length distribution in cells is often regulated to fit specific tasks. In comparison to the well-studied regulation of the average filament length (e.g., using capping proteins), controlling the width of the distribution is less well understood. We utilize two complementary methods to measure the effect of alpha-actinin on the width of the distribution of lengths of F-actin in vitro. Analyzing transmission electron micrographs shows that crosslinking by alpha-actinin reduces the width of the length distribution of F-actin, decreasing the coefficient of variation by two- to threefold. Analysis of fluorescence data from depolymerization assays confirms this observation. We suggest a mechanistic molecular model in which a local (weak) stabilization of crosslinked monomers in the filament is the physical origin of the decrease in the variance of lengths. Although alpha-actinin is known to bind reversibly to F-actin, our model shows that even weak binding can produce this effect, and that in fact it persists throughout a wide range of binding strengths.

Effects of adrenalectomy and glucocorticoids on rat brain dopamine receptors

The effects of adrenalectomy (ADX) and dexamethasone (DEX) treatment on brain dopamine (DA) receptors of ovariectomized (OVX) rats were investigated by autoradiography using binding of the D1 and D2 antagonists ligands [3H]SCH 23390 and [3H]spiperone, respectively. Fourteen days after ADX, D1 receptors decreased in the middle striatum (M.CPu) and in the dorsal area of the posterior striatum (P.CPu). A more pronounced decrease was observed in the substantia nigra (SN) and no significant changes occurred in the anterior striatum (A.CPu), globus pallidus (GP) and accumbens (Acb). D2 receptors decreased in the M.CPu and dorsal area of the P.CPu and remained unchanged in the A.CPu as compared to OVX rats. Twenty-eight days after ADX, D1 and D2 receptors decreased in the A.CPu (D2), in the M.CPu (D2) and substantially in the SN (D1). DEX treatment (14 days, 0.5 mg/kg, b.i.d., IM, starting 14 days after ADX) reversed these effects in the A.CPu (D2), M.CPu (D2) and SN (D1) when compared to ADX+OVX rats. DEX also increased the density of D1 receptors in Acb, A.CPu and M.CPu when compared to OVX rats. Striatal homogenates of rats treated chronically with ACTH and corticosterone had an increased density of D1 receptors while these treatments alone left these receptors unchanged, thus suggesting either a minor role or no role of the changes in ACTH levels following glucocorticoids manipulations. Our results suggest that the adrenals play a role in the modulation of DA receptors activity in the rat brain.

Effect of estradiol and progesterone on rat striatal dopamine uptake sites

Striatal dopamine (DA) uptake sites labelled with [3H]GBR-12935 binding were investigated in ovariectomized (OVX) rats acutely treated with 17 beta-estradiol (E2) or progesterone (P). One injection of E2 (100 ng, SC) to OVX rats increased plasma levels of this steroid after 15 min while plasma prolactin (PRL) levels remained unchanged. The E2 injection left striatal [3H]GBR-12935 binding affinity unchanged while the maximum density increased 15 and 30 min after the injection (+24% and +18%, respectively). One injection of P (110 micrograms, SC) to OVX rats increased this steroid plasma level from 15 to 120 min while plasma PRL levels remained unchanged. [3H]GBR-12935 binding density and affinity remained unchanged up to 120 min after the injection. Thus, acutely, E2 but not P, modulated striatal DA uptake sites in OVX rats. The effect of E2 appeared in coincidence with the peak of this steroid plasma concentration. This increase was rapid and is probably nongenomic and suggests a causal effect relationship as well as a presynaptic site of action of E2.