Unfreezing of molecular motions in protein-polymer conjugates: a calorimetric study

Protein-polymer conjugates are a promising class of biohybrids. In this work, the dynamics of a set of biodegradable conjugates myoglobin-poly(ethyl ethylene phosphate) (My-PEEP) with variations in the number of attached polymers and their molar mass in the dry-state, have been investigated to understand the role of polymer on protein dynamics. We performed Differential Scanning Calorimetry measurements between 190 and 300 K, observing the large-scale dynamics arising from reorganization of conformational states, i.e. within the 100 s timescale. The application of an annealing time during the cooling scans was used to investigate the non-equilibrium glassy-state of the samples, observing the relaxation enthalpy at different annealing temperatures. This procedure permitted to extensively describe the transition broadness and the system relaxation kinetics in the glassy state. The samples show an experimental behaviour different from the theoretical predictions, suggesting the establishment of interactions among the protein and the polymer chains. The different behaviour of the conjugates and the physical mixture (composed of the protein and the polymer physically mixed) highlighted the importance of the covalent bond in defining the system dynamics

The NH2D/NH3 ratio toward pre-protostellar cores around the UCHII region in IRAS 20293+3952

The deuterium fractionation, Dfrac, has been proposed as an evolutionary indicator in pre-protostellar and protostellar cores of low-mass star-forming regions. We investigate Dfrac, with high angular resolution, in the cluster environment surrounding the UCHII region IRAS 20293+3952. We performed high angular resolution observations with the IRAM Plateau de Bure Interferometer (PdBI) of the ortho-NH2D 1_{11}-1_{01} line at 85.926 GHz and compared them with previously reported VLA NH3 data. We detected strong NH2D emission toward the pre-protostellar cores identified in NH3 and dust emission, all located in the vicinity of the UCHII region IRAS 20293+3952. We found high values of Dfrac~0.1-0.8 in all the pre-protostellar cores and low values, Dfrac<0.1, associated with young stellar objects. The high values of Dfrac in pre-protostellar cores could be indicative of evolution, although outflow interactions and UV radiation could also play a role.Comment: 5 pages, 3 figures. Accepted for publication in Astronomy and Astrophysics Letter

Low-blood lymphocyte number and lymphocyte decline as key factors in COPD outcomes: a longitudinal cohort study

Background: Smokers with and without chronic obstructive pulmonary disease (COPD) are at risk of severe outcomes like exacerbations, cancer, respiratory failure, and decreased survival. The mechanisms for these outcomes are unclear; however, there is evidence that blood lymphocytes (BL) number might play a role. Objective: The objective of this study is to investigate the relationship between BL and their possible decline over time with long-term outcomes in smokers with and without COPD. Methods: In 511 smokers, 302 with COPD (COPD) and 209 without COPD (noCOPD), followed long term, we investigated whether BL number and BL decline over time might be associated with long-term outcomes. Smokers were divided according to BL number in high-BL (=1, 800 cells/µL) and low-BL (<1, 800 cells/µL). Clinical features, cancer incidence, and mortality were recorded during follow-up. BL count in multiple samples and BL decline over time were calculated and related to outcomes. Results: BL count was lower in COPD (1, 880 cells/µL) than noCOPD (2, 300 cells/µL; p < 0.001). 43% of COPD and 23% of noCOPD had low-BL count (p < 0.001). BL decline over time was higher in COPD than noCOPD (p = 0.040). 22.5% of the whole cohort developed cancer which incidence was higher in low-BL subjects and in BL decliners than high-BL (31 vs. 18%; p = 0.001) and no decliners (32 vs. 19%; p = 0.002). 26% in the cohort died during follow-up. Furthermore, low-BL count, BL decline, and age were independent risk factors for mortality by Cox regression analysis. Conclusion: BL count and BL decline are related to worse outcomes in smokers with and without COPD, which suggests that BL count and decline might play a mechanistic role in outcomes deterioration. Insights into mechanisms inducing the fall in BL count could improve the understanding of COPD pathogenesis and point toward new therapeutic measures

Aquazol as a binder for retouching paints. An evaluation through analytical pyrolysis and thermal analysis

Aquazol poly (2-ethyl-oxazoline) is a tertiary aliphatic amide, with physical and chemical properties that are exploited in a variety of ways, from pharmaceutical applications to the conservation of cultural heritage. In this study, we evaluated the use of Aquazol as a new binder for retouching paint in the restoration of artworks. Aquazol 500 admixed with various formulations of organic red pigments was used to prepare paint replicas which were artificially aged and investigated by a multi-analytical approach based on analytical pyrolysis coupled with gas chromatography and mass spectrometry (Py-GC/MS), and thermogravimetry (TG), complemented by FTIR and LIBS spectroscopy. This is the first study on the ageing phenomena of Aquazol 500 using analytical pyrolysis and thermogravimetric analysis. The influence of the pigments' components on the pyrolysis behavior of Aquazol was also investigated. The paint replicas did not show significant modifications during artificial ageing. This thus highlights the optimal properties of Aquazol 500 as a binder for retouching, in addition to its already established suitability as a filler or consolidant in the restoration of artifacts. Interestingly, when Aquazol 500 is used in formulations containing organic pigments, Aquazol-pigment interactions are observed, strongly depending on the pigment used

Interstellar deuterated ammonia: From NH3 to ND3

We use spectra and maps of NH2D, ND2H, and ND3, obtained with the CSO, IRAM 30m and Arecibo telescopes, to study deuteration processes in dense cores. The data include the first detection of the hyperfine structure of ND2H. The emission of ND2H and ND3 does not seem to peak at the positions of the embedded protostars, but instead at offset positions, where outflow interactions may occur. A constant ammonia fractionation ratio in star-forming regions is generally assumed to be consistent with an origin on dust grains. However, in the pre-stellar cores studied here, the fractionation varies significantly when going from NH3 to ND3. We present a steady state model of the gas-phase chemistry for these sources, which includes passive depletion onto dust grains and multiply saturated deuterated species up to five deuterium atoms (e.g. CD5+). The observed column density ratios of all four ammonia isotopologues are reproduced within a factor of 3 for a gas temperature of 10 K. We also predict that deuterium fractionation remains significant at temperatures up to 20 K. ND and NHD, which have rotational transitions in the submillimeter domain are predicted to be abundant.Comment: 14 pages, 12 figures, 12 table

Expression pattern of four storage xyloglucan mobilization-related genes during seedling development of the rain forest tree Hymenaea courbaril L.

During seedling establishment, cotyledons of the rain forest tree Hymenaea courbaril mobilize storage cell wall xyloglucan to sustain growth. The polysaccharide is degraded and its products are transported to growing sink tissues. Auxin from the shoot controls the level of xyloglucan hydrolytic enzymes. It is not yet known how important the expression of these genes is for the control of storage xyloglucan degradation. In this work, partial cDNAs of the genes xyloglucan transglycosylase hydrolase (HcXTH1) and β-galactosidase (HcBGAL1), both related to xyloglucan degradation, and two other genes related to sucrose metabolism [alkaline invertase (HcAlkIN1) and sucrose synthase (HcSUS1)], were isolated. The partial sequences were characterized by comparison with sequences available in the literature, and phylogenetic trees were assembled. Gene expression was evaluated at intervals of 6 h during 24 h in cotyledons, hypocotyl, roots, and leaves, using 45-d-old plantlets. HcXTH1 and HcBGAL1 were correlated to xyloglucan degradation and responded to auxin and light, being down-regulated when transport of auxin was prevented by N-1-naphthylphthalamic acid (NPA) and stimulated by constant light. Genes related to sucrose metabolism, HcAlkIN1 and HcSUS1, responded to inhibition of auxin transport in consonance with storage mobilization in the cotyledons. A model is proposed suggesting that auxin and light are involved in the control of the expression of genes related to storage xyloglucan mobilization in seedlings of H. courbaril. It is concluded that gene expression plays a role in the control of the intercommunication system of the source–sink relationship during seeding growth, favouring its establishment in the shaded environment of the rain forest understorey

The Influence of Deuteration and Turbulent Diffusion on the Observed D/H Ratio

The influence of turbulent mixing on the chemistry of the interstellar medium has so far received little attention. Previous studies of this effect have suggested that it might play an important role in mixing the various phases of the interstellar medium. In this paper we examine the potential effects of turbulent diffusion on the deuterium chemistry within molecular clouds. We find that such mixing acts to reduce the efficiency of deuteration in these clouds by increasing the ionization fraction and reducing freeze-out of heavy molecules. This leads to lower abundances for many deuterated species. We also examine the influence of turbulent mixing on the transition from atomic hydrogen to H2 and from atomic deuterium to HD near the cloud edge. We find that including turbulent diffusion in our models serves to push these transitions deeper into the cloud and helps maintain a higher atomic fraction throughout the cloud envelope. Based on these findings, we propose a new process to account for the significant scatter in the observed atomic D/H ratio for galactic sightlines extending beyond the Local Bubble. Although several mechanisms have been put forward to explain this scatter, they are unable to fully account for the range in D/H values. We suggest a scenario in which turbulent mixing of atomic and molecular gas at the edges of molecular clouds causes the observed atomic D/H ratio to vary by a factor of ~2.Comment: 14 pages, 14 figures, accepted for publication in Ap

Quantitative description of temperature induced self-aggregation thermograms determined by differential scanning calorimetry

A novel thermodynamic approach for the description of differential scanning calorimetry (DSC) experiments on self-aggregating systems is derived and presented. The method is based on a mass action model where temperature dependence of aggregation numbers is considered. The validity of the model was confirmed by describing the aggregation behavior of poly(ethylene oxide)-poly(propylene oxide) block copolymers, which are well-known to exhibit a strong temperature dependence. The quantitative description of the thermograms could be performed without any discrepancy between calorimetric and van 't Hoff enthalpies, and moreover, the aggregation numbers obtained from the best fit of the DSC experiments are in good agreement with those obtained by light scattering experiments corroborating the assumptions done in the derivation of the new model

An ISO--SWS survey of molecular hydrogen in Starburst and Seyfert Galaxies

We present results from a survey of molecular hydrogen emission from a sample of Starburst and Seyfert galaxies carried out with the Infrared Space Observatory (ISO). Pure rotational H_2 emission has been detected in a number of extragalactic objects and a variety of environments. A number of transitions from S(7) to S(0) are detected in both Starbursts and Seyferts. Using excitation diagrams we derive temperatures and masses of the ``warm'' molecular hydrogen. We find that the temperature of the ``warm'' gas is similar in Starbursts and Seyferts (those Seyferts for which we have firm detections of the S(0) line) with a value of around T~150 K. This ``warm'' gas accounts for as much as 10% of the total galactic mass (as probed by CO molecular observations) in Starbursts. The fraction of ``warm'' gas is overall higher in Seyferts, ranging between 2--35%. We then investigate the origin of the warm H_2 emission. Comparison with published theoretical models and Galactic templates implies that although emission from photodissociation regions (PDR) alone could explain the emission from Starbursts and Seyferts, most likely a combination of PDR, shock emission and gas heated by X-rays (mostly for the Seyferts) is responsible for H_2 excitation in extragalactic environments. Finally, we find that although PAH and H_2 line emission correlate well in Starbursts and the large scale emission in AGN, H_2 emission is much stronger compared to PAH emission in cases where a ``pure'' AGN dominates the energy output.Comment: Astronomy and Astrophysics in pres