Environmental cleaning mission Bioconversion of oxidatively fragmented polyethylene plastic waste to value-added copolyesters

The innovative recycling method, we are proposing, relies upon the controlled oxidative fragmentation of waste LDPE plastic to the inexpensive substrates for future sustainable production of PHAs with the aid of Cupriavidus necator. LDPE oxidized fragments (PE-F) were obtained from the re-engineering LDPE film by means of pro-oxidant/pro-degradant additives, followed by treatment under natural UV light. Cupriavidus necator was grown in either tryptone soya broth (TSB) or basal salt medium (BSM) supplemented with PE-F for 48 h. PHA production was higher in TSB supplemented with PE-F (29%) than in TSB alone (only 0.6%). No PHA was detected in either BSM alone or BSM supplemented with PE-F. The recovered PHA was characterized using GPC, NMR, and electrospray ionization tandem mass spectrometry (ESI-MS/MS). These analytical tools applied confirmed that the resulting PHA was a terpolymer having an average molar mass of 624 kg/mol and consisting of 3-hydroxybutyrate (HB), 3-hydroxyvalerates (HV) and 3-hydroxyhexanoate (HH) co-monomer units randomly distributed along the chain backbone

Observations and Recommendations for the Calibration of Landsat 8 OLI and Sentinel 2 MSI for Improved Data Interoperability

Combining data from multiple sensors into a single seamless time series, also known as data interoperability, has the potential for unlocking new understanding of how the Earth functions as a system. However, our ability to produce these advanced data sets is hampered by the differences in design and function of the various optical remote-sensing satellite systems. A key factor is the impact that calibration of these instruments has on data interoperability. To address this issue, a workshop with a panel of experts was convened in conjunction with the Pecora 20 conference to focus on data interoperability between Landsat and the Sentinel 2 sensors. Four major areas of recommendation were the outcome of the workshop. The first was to improve communications between satellite agencies and the remote-sensing community. The second was to adopt a collections-based approach to processing the data. As expected, a third recommendation was to improve calibration methodologies in several specific areas. Lastly, and the most ambitious of the four, was to develop a comprehensive process for validating surface reflectance products produced from the data sets. Collectively, these recommendations have significant potential for improving satellite sensor calibration in a focused manner that can directly catalyze efforts to develop data that are closer to being seamlessly interoperable

Liquefied Bleed for Stability and Efficiency of High Speed Inlets

No abstract availabl

Mastering Cryogenic Propellants

No abstract availabl

Landsat-7 ETM+: 12 years On-Orbit Reflective-Band Radiometric Performance

The Landsat-7 ETM+ sensor has been operating on orbit for more than 12 years and characterizations of its performance have been ongoing over this period. In general, the radiometric performance of the instrument has been remarkably stable: (1) Noise performance has degraded by 2% or less overall, with a few detectors displaying step changes in noise of 2% or less, (2) Coherent noise frequencies and magnitudes have generally been stable, though the within-scan amplitude variation of the 20kHz noise in bands 1 and 8 disappeared with the failure of the scan line corrector and a new similar frequency noise (now about 18kHz) has appeared in two detectors in band 5 and increased in magnitude with time, (3) Bias stability has been better than 0.25 DN out of a normal value of 15 DN in high gain, (4) Relative gains, the differences in response between the detectors in the band, have generally changed by 0.1% or less over the mission, with the exception of a few detectors with a step response change of 1% or less and (5) Gain stability averaged across all detectors in a band, which is related to the stability of the absolute calibration, has been more stable than the techniques used to measure it. Due to the inability to confirm changes in the gain (beyond a few detectors that have been corrected back to the band average), ETM+ reflective band data continues to be calibrated with the pre-launch measured gains. In the worst case some bands may have changed as much as 2% in uncompensated absolute calibration over the 12 years

Mapping a multiplexed zoo of mRNA expression

In situ hybridization methods are used across the biological sciences to map mRNA expression within intact specimens. Multiplexed experiments, in which multiple target mRNAs are mapped in a single sample, are essential for studying regulatory interactions, but remain cumbersome in most model organisms. Programmable in situ amplifiers based on the mechanism of hybridization chain reaction (HCR) overcome this longstanding challenge by operating independently within a sample, enabling multiplexed experiments to be performed with an experimental timeline independent of the number of target mRNAs. To assist biologists working across a broad spectrum of organisms, we demonstrate multiplexed in situ HCR in diverse imaging settings: bacteria, whole-mount nematode larvae, whole-mount fruit fly embryos, whole-mount sea urchin embryos, whole-mount zebrafish larvae, whole-mount chicken embryos, whole-mount mouse embryos and formalin-fixed paraffin-embedded human tissue sections. In addition to straightforward multiplexing, in situ HCR enables deep sample penetration, high contrast and subcellular resolution, providing an incisive tool for the study of interlaced and overlapping expression patterns, with implications for research communities across the biological sciences

Mass spectrometry reveals molecular structure of polyhydroxyalkanoates attained by bioconversion of oxidized polypropylene waste fragments

This study investigated the molecular structure of the polyhydroxyalkanoate (PHA) produced via a microbiological shake flask experiment utilizing oxidized polypropylene (PP) waste as an additional carbon source. The bacterial strain Cupriavidus necator H16 was selected as it is non-pathogenic, genetically stable, robust, and one of the best known producers of PHA. Making use of PHA oligomers, formed by controlled moderate-temperature degradation induced by carboxylate moieties, by examination of both the parent and fragmentation ions, the ESI-MS/MS analysis revealed the 3-hydroxybutyrate and randomly distributed 3-hydroxyvalerate as well as 3-hydroxyhexanoate repeat units. Thus, the bioconversion of PP solid waste to a value-added product such as PHA tert-polymer was demonstrated.This research was funded by the Research Investment Fund, University of Wolverhampton, Faculty of Science and Engineering, UK. This work was also partially supported the European Regional Development Fund Project EnTRESS No 01R16P00718 and the PELARGODONT Project UM0-2016/22/Z/STS/00692 financed under the M-ERA.NET 2 Program of Horizon 2020.Published onlin

Sauver Byzance de la barbarie du monde

Il volume ripercorre la trattazione del mitema di Bisanzio nella letteratura francese e francofona dalle origini ai giorni nostr

Mapping a multiplexed zoo of mRNA expression

In situ hybridization methods are used across the biological sciences to map mRNA expression within intact specimens. Multiplexed experiments, in which multiple target mRNAs are mapped in a single sample, are essential for studying regulatory interactions, but remain cumbersome in most model organisms. Programmable in situ amplifiers based on the mechanism of hybridization chain reaction (HCR) overcome this longstanding challenge by operating independently within a sample, enabling multiplexed experiments to be performed with an experimental timeline independent of the number of target mRNAs. To assist biologists working across a broad spectrum of organisms, we demonstrate multiplexed in situ HCR in diverse imaging settings: bacteria, whole-mount nematode larvae, whole-mount fruit fly embryos, whole-mount sea urchin embryos, whole-mount zebrafish larvae, whole-mount chicken embryos, whole-mount mouse embryos and formalin-fixed paraffin-embedded human tissue sections. In addition to straightforward multiplexing, in situ HCR enables deep sample penetration, high contrast and subcellular resolution, providing an incisive tool for the study of interlaced and overlapping expression patterns, with implications for research communities across the biological sciences

Preparation and characterization of polysaccharides based smart materials for surface and interface modification

In the present work, innovative smart polysaccharide-base materials were successful developed. Three polysaccharides, composed by glucopyranose repetitive units but with different configuration of the glycosidic bonds or degree of branching have been selected: amylose, amylopectin and dextran. Amylose and amylopectin were functionalized with an alkynyl derivative of spiropyran (SPCC) and/or propargyl alcohol by a two steps procedure consisting in the derivatization of glucopyranose units with azide at the C6 position followed by Cu(I)-catalysed azide-alkyne cycloaddition (CuAAc). Substitution degrees with spiropyran (DSSP) between 0.10 and 0.95 were achieved by simply modulating the molar ratio between alkyne species and polysaccharide in the CuAAc reaction, as it was confirmed by FT-IR and NMR spectroscopy characterization. The UV-Vis spectra of SPCC-modified amyloses in DMF solution kept in the dark exhibited an absorbance band with maximum at ~346 nm, ascribed to spiropyran units. The intensity of the absorbance was found to increase linearly with the DSSP. Upon irradiation with UV light, a band at ~560 nm appears, due to the conversion of spiropyran to zwitterionic merocyanine, its intensity linearly increasing with DSSP too. ICP-MS analysis showed the presence of small amount (< 270 ppm) of residual Cu from the catalyst in the functionalized polysaccharides. However, EPR spectroscopy indicated that Cu2+ species are bonded to different moieties and they do not significant interfere in the optical behaviour. In order to evaluate the combined effect of solvent and photo-isomerization on the solubility and solvatochromism of the spiropyran functionalized polysaccharides, ASP40 was selected and solubilized/dispersed in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), water, 2,2,2-trifluoroethanol (TFE), ethanol, DMSO, DMF, and tetrahydrofuran (THF). Four distinct photochromic behaviours depending on the solubility were observed which on turn depend on the solvent polarity: i) good solvents (DMF, DMSO) where the most stable form is a mixture of spiropyran in closed conformation and a not well identify open conformer exhibiting yellow colour, ii) ad solvent (water and alcohols) that are not able to solubilize the functionalized polysaccharide but allow the photo-isomerization of the spiro form to merocyanine, iii) intermediate solvent (THF) that almost solubilizes the functionalized polysaccharide when the grafted groups are in the closed apolar conformation but allows a switchable solubility reduction by irradiation with UV-Vis light, iv) the very polar HFIP that induced inverse photochromism. The filmability property of the functionalized amyloses was tested by three different coating methods on glass and paper as substrates. Coatings on glass were prepared by solvent casting and spin coating and they were characterized by UV/Vis spectroscopy that showed the isomerization of SPMC occurring, even if it was slower than in solution. AFM analysis of the films obtained by spin coating from HFIP solutions evidenced the presence of pores whose volume increased with the increase of the substitution degree of the polysaccharide. The contact angle analysis of films prepared by solution casting on glass showed a higher hydrophilicity for the film with SP groups than for the azidated precursor and the difference was higher after irradiation of the films with UV light. A similar result was observed for films on paper that were obtained by dip coating. The treated natural substrate showed photochromic properties and polarity increase after irradiation with UV light. These findings indicate that the proposed synthetic strategy can be exploit to prepare photochromic materials that can be used as coating for paper to provide the natural substrate with photochromism as well as waterproof properties. The second part of this work was focused on the fabrication of Janus particles with polysaccharide grafted on part of the surface. Indeed, anisotropically functionalized particles are attractive for their peculiar characteristics such as hierarchical self-assembling and tuneable amphiphilicity. In particular, this work was focused on the development of an efficient grafting method allowing to prepare Janus particles with the largest superficial concentration of polysaccharide. In order to prepare the Janus silica particles (JP), silica nanoparticles prepared by Stöber method (SNPs) were chosen after comparison with commercial silica particles (CSPs). Then, they were selectively modified at one side after immobilization at wax-water interface in a wax-in-water emulsion. Under the assumption that the particles at the solid wax particle surface had only one side exposed to water, the hydroxyl groups thereon were modified by reaction with functionalized alkyl trialkoxy silane in order to graft amine and azide moieties on the particles surface. Dextran (a water soluble, linear α-D-1,6-glucose-linked glucan) was selected for this study. In order to graft polysaccharides on functionalized silica Janus particles, two well-known coupling reactions were compared: reductive amination with aldehyde and CuAAc reaction. The reductive amination reaction was carried out between amine groups on silica Janus particles and aldehydes groups on dextran. Either natural occurring aldehyde at the reducing chain-end of the polysaccharide or aldehyde groups produced by oxidation along the polymer backbone were exploited. CuAAc reaction was carried out between dextran bearing alkyne moieties and azidated Janus particles. All the prepared Janus particles were characterized by spectroscopic analysis, calorimetry and the grafting degree was evaluated by spectrophotometric titration. The effective asymmetrical nature of the obtained Janus particles was assessed by functionalization with a citrate-stabilized Au nanoparticle dispersion followed by TEM analysis. Indeed, the stained samples clearly show the specific absorption of the Au nanoparticles onto one of the two differently functionalized side of the surface of each Janus particle. Such an occurrence was ascribed to the different nature of the functional groups at the two sides of the Janus particle surface, the one at one side only interacting with the gold nanoparticles