458 research outputs found
Process integration study of tail-end Ca-Looping process for CO2capture in cement plants
In this work, the integration of Calcium looping (CaL) process into a cement plant for post-combustion CO2capture is assessed via process simulations. In the proposed scheme, the carbonator of the CaL process is used as an end-of-pipe unit to capture the CO2from the cement kiln gas. From the results obtained, it is demonstrated that CO2capture efficiencies of the order of 90% are achievable, with CaL reactors operating in conditions not far from those demonstrated for application in power plants. The integration of the tail-end CaL process results in a significant increase of the total fuel consumption (about two to three times higher) compared to the benchmark cement plant without CO2capture. On the other hand, the heat from the CaL process can be recovered by a steam cycle producing decarbonized electric power that may exceed the needs of the plant auxiliaries (including the ASU and the CO2compression and purification unit), exporting in this way electricity to the grid and so resulting in CO2emission credits from a life cycle perspective. The resulting specific primary energy consumption for CO2avoided (SPECCA) highly depends on the reference power generation technology considered, and it ranges between 2.7 and 3.7 MJLHV/kgCO2in a coal-fired power generation scenario. As for the retrofittability of existing cement plants, the operation of the suspension preheating tower after the implementation of the CaL unit, as well as the position of the CaL carbonator with respect to the raw mill, have been assessed. Based on the results obtained, no critical issues have been found from a technical point of view in the adoption of the tail-end CaL process in existing cement kilns
Co-expression of functional human Heme Oxygenase 1, Ecto-5'-Nucleotidase and ecto-nucleoside triphosphate diphosphohydrolase-1 by "self-cleaving" 2A peptide system
We developed an F2A-based multicistronic system to evaluate functional effects of co-expression of three proteins important for xenotransplantation: heme oxygenase 1 (HO1), ecto-5'-nucleotidase (E5NT) and ecto-nucleoside triphosphate diphosphohydrolase-1 (ENTPD1). The tricistronic p2A plasmid that we constructed was able to efficiently drive concurrent expression of HO1, E5NT and ENTPD1 in HEK293T cells. All three overexpressed proteins possessed relevant enzymatic activities, while addition of furin site interfered with protein expression and activity. We conclude that our tricistronic p2A construct is effective and optimal to test the combined protective effects of HO1, E5NT and ENTPD1 against xeno-rejection mechanisms
A smartphone-based chemosensor to evaluate antioxidants in agri-food matrices by in situ AuNP formation
In recent years, there has been a continuously growing interest in antioxidants by both customers and food industry. The beneficial health effects of antioxidants led to their widespread use in fortified functional foods, as dietary supplements and as preservatives. A variety of analytical methods are available to evaluate the total antioxidant capacity (TAC) of food extracts and beverages. However, most of them are expensive, time-consuming, and require laboratory instrumentation. Therefore, simple, cheap, and fast portable sensors for point-of-need measurement of antioxidants in food samples are needed. Here, we describe a smartphone-based chemosensor for on-site assessment of TAC of aqueous matrices, relying on the antioxidant-induced formation of gold nanoparticles. The reaction takes place in ready-to-use analytical cartridges containing an hydrogel reaction medium preloaded with Au(III) and is monitored by using the smartphone’s CMOS camera. An analytical device including an LED-based lighting system was developed to ensure uniform and reproducible illumination of the analytical cartridge. The chemosensor permitted rapid TAC measurements of aqueous samples, including teas, herbal infusions, beverages, and extra virgin olive oil extracts, providing results that correlated with those of the reference methods for TAC assessment, e.g., oxygen radical absorbance capacity (ORAC)
Technological innovation in creative clusters. The case of laser in conservation of artworks in Florence
The field of laser application to the restoration and cleaning of cultural assets is amongst the most thriving developments of recent times. Ablative laser technological systems are able to clean and protect inestimable works of art subject to atmospheric agents and degradation over time. This new technology, which has been developing for the last forty year, is now available to restorers and has received a significant success all over Europe. An important contribution in the process of laser innovation has been carried out in Florence by local actors belonging to a creative cluster. The objects of the analysis are the genesis of this innovation in this local Florentine context, and the relationships among the main actors who have contributed in it. The study investigates how culture can play a part in the generation of ideas and innovations, and which are the creative environments that can favour it. In this context, the issue of laser technologies for the restoration of cultural heritage has been analysed as a case study in the various paths taken by the Creative Capacity of the Culture (CCC)
The Adipose Organ Is a Unitary Structure in Mice and Humans
Obesity is the fifth leading cause of death worldwide. In mice and humans with obesity, the adipose organ undergoes remarkable morpho-functional alterations. The comprehension of the adipose organ function and organization is of paramount importance to understand its pathology and formulate future therapeutic strategies. In the present study, we performed anatomical dissections, magnetic resonance imaging, computed axial tomography and histological and immunohistochemical assessments of humans and mouse adipose tissues. We demonstrate that most of the two types of adipose tissues (white, WAT and brown, BAT) form a large unitary structure fulfilling all the requirements necessary to be considered as a true organ in both species. A detailed analysis of the gross anatomy of mouse adipose organs in different pathophysiological conditions (normal, cold, pregnancy, obesity) shows that the organ consists of a unitary structure composed of different tissues: WAT, BAT, and glands (pregnancy). Data from autoptic dissection of 8 cadavers, 2 females and 6 males (Age: 37.5 ± 9.7, BMI: 23 ± 2.7 kg/m2) and from detailed digital dissection of 4 digitalized cadavers, 2 females and 2 males (Age: 39 ± 14.2 years, BMI: 22.8 ± 4.3 kg/m2) confirmed the mixed (WAT and BAT) composition and the unitary structure of the adipose organ also in humans. Considering the remarkable endocrine roles of WAT and BAT, the definition of the endocrine adipose organ would be even more appropriate in mice and humans
Targeting TLR4 during vaccination boosts MAdCAM-1+ lymphoid stromal cell activation and promotes the aged germinal center response
The failure to generate enduring humoral immunity after vaccination is a hallmark of advancing age. This can be attributed to a reduction in the germinal center (GC) response, which generates long-lived antibody-secreting cells that protect against (re)infection. Despite intensive investigation, the primary cellular defect underlying impaired GCs in aging has not been identified. Here, we used heterochronic parabiosis to demonstrate that GC formation was dictated by the age of the lymph node (LN) microenvironment rather than the age of the immune cells. Lymphoid stromal cells are a key determinant of the LN microenvironment and are also an essential component underpinning GC structure and function. Using mouse models, we demonstrated that mucosal adressin cell adhesion molecule-1 (MAdCAM-1)-expressing lymphoid stromal cells were among the first cells to respond to NP-KLH + Alum immunization, proliferating and up-regulating cell surface proteins such as podoplanin and cell adhesion molecules. This response was essentially abrogated in aged mice. By targeting TLR4 using adjuvants, we improved the MAdCAM-1+ stromal cell response to immunization. This correlated with improved GC responses in both younger adult and aged mice, suggesting a link between stromal cell responses to immunization and GC initiation. Using bone marrow chimeras, we also found that MAdCAM-1+ stromal cells could respond directly to TLR4 ligands. Thus, the age-associated defect in GC and stromal cell responses to immunization can be targeted to improve vaccines in older people
Effectiveness of Neuraminidase Inhibitors for Preventing Staff Absenteeism during Pandemic Influenza
Timely and adequate treatment and prophylaxis may reduce absenteeism among healthcare workers during the peak of a pandemic
Observation of mesoscopic crystalline structures in a two-dimensional Rydberg gas
The ability to control and tune interactions in ultracold atomic gases has
paved the way towards the realization of new phases of matter. Whereas
experiments have so far achieved a high degree of control over short-ranged
interactions, the realization of long-range interactions would open up a whole
new realm of many-body physics and has become a central focus of research.
Rydberg atoms are very well-suited to achieve this goal, as the van der Waals
forces between them are many orders of magnitude larger than for ground state
atoms. Consequently, the mere laser excitation of ultracold gases can cause
strongly correlated many-body states to emerge directly when atoms are
transferred to Rydberg states. A key example are quantum crystals, composed of
coherent superpositions of different spatially ordered configurations of
collective excitations. Here we report on the direct measurement of strong
correlations in a laser excited two-dimensional atomic Mott insulator using
high-resolution, in-situ Rydberg atom imaging. The observations reveal the
emergence of spatially ordered excitation patterns in the high-density
components of the prepared many-body state. They have random orientation, but
well defined geometry, forming mesoscopic crystals of collective excitations
delocalised throughout the gas. Our experiment demonstrates the potential of
Rydberg gases to realise exotic phases of matter, thereby laying the basis for
quantum simulations of long-range interacting quantum magnets.Comment: 10 pages, 7 figure
Spectroscopic, Morphological and Mechanistic Investigation of the Solvent.Promoted Aggregation of Porphyrins Modified in meso-positions by Glucosylated steroids
Solvent-driven aggregation
of a series of porphyrin derivatives was
studied by UV/Vis and circular dichroism
spectroscopy. The porphyrins are
characterised by the presence in the
meso positions of steroidal moieties
further conjugated with glucosyl
groups. The presence of these groups
makes the investigated macrocycles
amphiphilic and soluble in aqueous solvent,
namely, dimethyl acetamide/
water. Aggregation of the macrocycles
is triggered by a change in bulk solvent
composition leading to formation of
large architectures that express supramolecular
chirality, steered by the presence
of the stereogenic centres on the
periphery of the macrocycles. The aggregation
behaviour and chiroptical
features of the aggregates are strongly
dependent on the number of moieties
decorating the periphery of the porphyrin
framework. In particular, experimental
evidence indicates that the
structure of the steroid linker dictates
the overall chirality of the supramolecular
architectures. Moreover, the porphyrin
concentration strongly affects
the aggregation mechanism and the
CD intensities of the spectra. Notably,
AFM investigations reveal strong differences
in aggregate morphology that
are dependent on the nature of the appended
functional groups, and closely
in line with the changes in aggregation
mechanism. The suprastructures
formed at lower concentration show a
network of long fibrous structures
spanning over tens of micrometres,
whereas the aggregates formed at
higher concentration have smaller rodshaped
structures that can be recognised
as the result of coalescence of
smaller globular structures. The fully
steroid substituted derivative forms
globular structures over the whole concentration
range explored. Finally, a rationale
for the aggregation phenomena
was given by semiempirical calculations
at the PM6 level
Integration of Ca-Looping Systems for CO2Capture in Cement Plants
Ca-Looping (CaL) has been demonstrated as a promising technology for CO2capture in coal-fired power plants. A promising application is also in cement plants, where the CaO-rich material purged from the CaL process can replace part or all of the raw material used for clinker production. The aim of this work is to investigate two process integration options of the CaL system based on fluidized bed and entrained flow reactors in a clinker burning process. The main advantages, constrains and research questions of the two configurations are discussed, and the mass and energy balances of the whole processes are detailed and analyzed
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