► We present the effect induced by a ball milling process on cellulose. ► The cellulose amorphization and the mean size reduction of the crystallite domains were quantified. ► Ball milled cellulose ...shows increased water absorption and reduced thermal stability. ► The disappearance of the fibrous structure is evidenced as a consequence of the ball milling process.
This paper presents a detailed analysis of effect induced by a dry ball milling process on cellulose structure, morphology and properties. The partial amorphization of cellulose was qualitatively estimated by ATR-FTIR analysis. Through WAXD analysis the crystallinity index and the mean size of the cellulose crystallite domains were calculated, both these parameters showing a progressive decrease as a function of the milling time. In particular, crystallinity index decreased from 0.53 to 0.15 after 60min ball milling, whereas the mean size of the cellulose crystallite domains showed a reduction from the original value of about 4.0nm up to about 3.4nm after 30min. These quantitative results were confirmed by 13C CP-MAS NMR analysis and measurements of the proton spin-lattice relaxation time in the rotating frame (T1ρ1H). Moreover, the increasing of the amount of water absorbed by cellulose samples (from 7.3wt% for untreated cellulose up to 11.6wt% for the cellulose sample ball milled for 60min) and the reduction of the thermal stability were evaluated by TGA. Finally, SEM analysis revealed that the original fibrous structure almost disappeared and was modified to a quasi-circular shape.
A new cylindrical detector for borehole muon radiography Saracino, G.; Ambrosino, F.; Anastasio, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
March 2023, 2023-03-00, Letnik:
1048
Journal Article
Recenzirano
Muons of cosmic origin have a great capability to penetrate through matter. This property is exploited in muon radiography, also known as muography, a technique which allows to highlight the presence ...of discontinuities of the mass density in the subsoil such as cavities, tunnels or rock masses. A detector of cylindrical geometry, optimized for borehole studies and with a diameter of 24 cm, was developed and tested . The scintillation light is read out by 384 Silicon Photomultipliers, directly coupled to the bars. The front-end and acquisition electronics, entirely housed inside the detector, are based on the EASIROC chip and are characterized by limited energy consumption (about 30 W for the entire detector). The detector has been designed in such a way as to simplify its construction as much as possible for its eventual mass production. In this article some details concerning the construction and preliminary results of measurements conducted in the Mt Echia (Naples, Italy) underground are presented.
•New PBSA/cellulose composites were prepared and characterized.•A new compatibilizing agent was synthesized and tested.•Amorphized cellulose (AC) was used as filler in comparison to crystalline ...cellulose.•Using AC, break elongation of composites was preserved also at high filler contents.•AC accelerated the soil burial degradation kinetic of PBSA.
Composites based on poly(butylene succinate-co-butylene adipate) (PBSA) containing amorphized and crystalline cellulose reinforcements have been prepared and characterized. In order to improve the polymer/filler interfacial adhesion, an efficient compatibilizing agent has been synthesized by chemical modification of PBSA and characterized by FT-IR, FT-NIR and 1H NMR spectroscopy. Uncompatibilized and compatibilized composites have been tested through morphological, mechanical, calorimetric and thermogravimetric analysis. Moreover, water vapor permeability and biodegradation kinetics of composites have been investigated. The addition to PBSA of cellulose fillers differing from each other by crystallinity degree and morphology, and the use of a compatibilizing agent have allowed modulating tensile and thermal properties, water vapor transmission rate and biodegradation kinetic of the composites.
A detailed analysis of the effect of calcium carbonate nanoparticles on crystallization of isotactic polypropylene (iPP) is reported in this contribution. CaCO3 nanoparticles with different crystal ...modifications (calcite and aragonite) and particle shape were added in small percentages to iPP. The nanoparticles were coated with two types of compatibilizer (either polypropylene-g-maleic anhydride copolymer, or fatty acids) to improve dispersion and adhesion with the polymer matrix. It was found that the type of coating agent used largely affects the nucleating ability of calcium carbonate towards formation of polypropylene crystals. CaCO3 nanoparticles coated with maleated polypropylene can successfully promote nucleation of iPP crystals, whereas the addition of nanosized calcium carbonate coated with fatty acids delays crystallization of iPP, the effect being mainly ascribed to the physical state of the coating in the investigated temperature range for crystallization of iPP, as well as to possible dissolution by fatty acids of heterogeneities originally present in the polypropylene matrix.
Nanocomposites composed of poly(ethylene terephthalate) (PET) filled with calcium carbonate particles of nanometer scale were prepared by polymerizing the polyester in the presence of the nanosized ...fillers. Besides plain calcium carbonate, carbonate nanoparticles coated with stearic acid were also used, in order to improve the compatibility between the polymeric matrix and nanofillers. Morphological analysis evidenced a good dispersion of both the nanopowders into the PET matrix, especially in the case of coated calcium carbonate. The strong interfacial adhesion between the two phases is also responsible for the increase of the glass transition and melting temperatures in the nanocomposites compared to plain PET. Finally, non-isothermal crystallization studies revealed that the coated CaCO3 is a good nucleating agent for PET. Analysis of non-isothermal crystallization data with the Ozawa theory was successful for plain PET and PET/un-CaCO3, but this method failed to describe the dynamic solidification of the PET/c-CaCO3 nanocomposite.
To describe the development and implementation of a prostate cancer screening intervention and risk assessment decision tool. .
Community health promotion with pre- and post-education knowledge ...questionnaires. .
Two predominantly African American churches in different suburban communities in Southern California. .
A convenience sample of 50 African American men aged from 30-75 years. .
A Prostate Cancer Screening Decision Aid was developed and used in conjunction with an educational intervention for African American men in two suburban communities in Southern California. The educational intervention was implemented in local African American churches. The intervention included a PowerPoint® presentation with a four-minute video. Men completed pre- and post-education knowledge questionnaires and a risk assessment decision tool. .
Prostate cancer knowledge, awareness of prostate cancer personal risks and benefits of prostate cancer screening, information needed for initiating discussions with provider, and intention to participate in shared decision making with healthcare providers. .
An 8% increase in knowledge was calculated when comparing pre- and post- education responses. Awareness of personal risks, having the information needed to initiate a discussion with a healthcare provider, intention to participate in shared decision making within six months, prostate cancer knowledge, and having had participated in screening increased. .
The intervention was successful in increasing knowledge and awareness of personal risks and providing tools to facilitate shared decision making with healthcare providers. .
Nurses can play a meaningful role in collaborating with community lay leaders to develop and implement effective health promotion interventions for African Americans.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Rapidly emerging SARS-CoV-2 variants jeopardize antibody-based countermeasures. Although cell culture experiments have demonstrated a loss of potency of several anti-spike neutralizing antibodies ...against variant strains of SARS-CoV-2
, the in vivo importance of these results remains uncertain. Here we report the in vitro and in vivo activity of a panel of monoclonal antibodies (mAbs), which correspond to many in advanced clinical development by Vir Biotechnology, AbbVie, AstraZeneca, Regeneron and Lilly, against SARS-CoV-2 variant viruses. Although some individual mAbs showed reduced or abrogated neutralizing activity in cell culture against B.1.351, B.1.1.28, B.1.617.1 and B.1.526 viruses with mutations at residue E484 of the spike protein, low prophylactic doses of mAb combinations protected against infection by many variants in K18-hACE2 transgenic mice, 129S2 immunocompetent mice and hamsters, without the emergence of resistance. Exceptions were LY-CoV555 monotherapy and LY-CoV555 and LY-CoV016 combination therapy, both of which lost all protective activity, and the combination of AbbVie 2B04 and 47D11, which showed a partial loss of activity. When administered after infection, higher doses of several mAb cocktails protected in vivo against viruses with a B.1.351 spike gene. Therefore, many-but not all-of the antibody products with Emergency Use Authorization should retain substantial efficacy against the prevailing variant strains of SARS-CoV-2.
The influence of calcium carbonate nanoparticles with different shapes (spherical and elongated) on the thermal properties and crystallization behavior of isotactic polypropylene was investigated. ...CaCO3 nanoparticles were covered by an appropriate coating agent to improve the interfacial adhesion between the filler and the polyolefin matrix. The nanocomposites were prepared by melt mixing and subsequent compression molding. A remarkable effect of CaCO3 on the thermal properties of iPP was observed. Moreover, the analysis of crystallization kinetics showed that CaCO3 nanopowder coated with PP-MA are efficient nucleating agents for iPP, and the overall crystallization rate results higher than plain iPP.
Abstract The homeobox containing gene HoxB7 is functionally associated with melanoma growth promotion through the direct transactivation of bFGF. Accordingly, the introduction of HoxB7 in the breast ...cancer line SkBr3 (SkBr3/B7), strongly increases its tumorigenic properties. Here we show that in SkBr3/B7 cells, HoxB7 regulates the expression of TALE Hox cofactors by increasing Pbx2 and Prep1 and decreasing Pbx1. The functional requirement of Hox cofactors in the oncogenic activity of HoxB7 was proven with a dominant-negative Pbx1 mutant, Pbx1NT, which sequesters Prep1 in the cytoplasm. The less aggressive phenotype of the SkBr3/B7/PbxNT cells, evaluated in vitro as well as in vivo , correlated well with increased apoptosis, decreased cycling and up-regulation of p16 and p53. Tumor cell-type specific functional effects of Pbx1NT were observed, possibly related to the presence of different Hox genes in melanoma or breast adenocarcinoma DNA–protein ternary complexes.
The SLIM experiment at the Chacaltaya high altitude laboratory was sensitive to nuclearites and Q-balls which could be present in the cosmic radiation as possible Dark Matter components. It was ...sensitive also to strangelets, i.e. small lumps of Strange Quark Matter predicted at such altitudes by various phenomenological models. The analysis of 427 m
2
of Nuclear Track Detectors exposed for 4.22 years showed no candidate event. New upper limits on the flux of downgoing nuclearites and Q-balls at the 90% C.L. were established. The null result also restricts models for strangelets propagation through the Earth atmosphere.
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