14 research outputs found
Assessment of dimensional stability, biodegradability, and fracture energy of bio composites reinforced with novel pine cone
In this investigation, biodegradable composites were fabricated with polycaprolactone (PCL) matrix reinforced with pine cone powder (15%, 30%, and 45% by weight) and compatibilized with graphite powder (0%, 5%, 10%, and 15% by weight) in polycaprolactone matrix by compression molding technique. The samples were prepared as per ASTM standard and tested for dimensional stability, biodegradability, and fracture energy with scanning electron micrographs. Water-absorption and thickness-swelling were performed to examine the dimensional stability and tests were performed at 23 °C and 50% humidity. Results revealed that the composites with 15 wt % of pine cone powder (PCP) have shown higher dimensional stability as compared to other composites. Bio-composites containing 15–45 wt % of PCP with low graphite content have shown higher disintegration rate than neat PCL. Fracture energy for crack initiation in bio-composites was increased by 68% with 30% PCP. Scanning electron microscopy (SEM) of the composites have shown evenly-distributed PCP particles throughout PCL-matrix at significantly high-degrees or quantities of reinforcing
Technical recommendations for clinical translation of renal MRI: a consensus project of the Cooperation in Science and Technology Action PARENCHIMA
Purpose The potential of renal MRI biomarkers has been increasingly recognised, but clinical translation requires more
standardisation. The PARENCHIMA consensus project aims to develop and apply a process for generating technical recommendations on renal MRI.
Methods A task force was formed in July 2018 focused on fve methods. A draft process for attaining consensus was distributed publicly for consultation and fnalised at an open meeting (Prague, October 2018). Four expert panels completed
surveys between October 2018 and March 2019, discussed results and refned the surveys at a face-to-face meeting (Aarhus,
March 2019) and completed a second round (May 2019).
Results A seven-stage process was defned: (1) formation of expert panels; (2) defnition of the context of use; (3) literature
review; (4) collection and comparison of MRI protocols; (5) consensus generation by an approximate Delphi method; (6)
reporting of results in vendor-neutral and vendor-specifc terms; (7) ongoing review and updating. Application of the process
resulted in 166 consensus statements.
Conclusion The process generated meaningful technical recommendations across very diferent MRI methods, while allowing for improvement and refnement as open issues are resolved. The results are likely to be widely supported by the renal
MRI community and thereby promote more harmonisation
Dynamics of
The decay mechanism of 47V* formed in direct kinematics (20Ne + 27Al is investigated within the collective clusterization approach of dynamical cluster decay model (DCM). All calculations are done for quadrupole (β
2i
-deformed) choice of fragments by taking optimum orientations over a wide range of center of mass energies (E
c. m.
∼ 83–125 MeV). According to the experimental evidence, there is a strong competition between fusion fission (FF) and deep inelastic collision (DIC) in the decay of 47V*, which are recognized as compound nucleus process and non-compound nucleus process, respectively. The decay cross sections of 47V* for both FF and DIC decay modes are addressed using DCM, and are found to be in agreement with the experimental data. It is important to mention that emitting fragments in both these decay channels maintain their homogeneity in terms of charge number, that lies in the region 3 ≤ Z ≤ 9. Hence, all possible isotopes contributing towards 3 ≤ Z ≤ 9 are taken into consideration here. Calculations of both FF and DIC are segregated on the basis of angular momentum windows, where 0 ≤ ℓ ≤ ℓ
cr
has been taken for FF and ℓ
cr
< ℓ ≤ ℓ
gr
for DIC, as the later operates only due to the partial
waves near grazing angular momentum. In DIC, preformation probability (P
0) is divided equally amongst
the most favoured outgoing fragments. Moreover, the behavior of fragmentation potential, preformation
probability, penetrability and emission time etc. is examined, in order to identify the most favorable isotopes
contributing towards FF and DIC
Effect of deformations and orientations in
Based on the preformed cluster model (PCM), we have extended our earlier study to investigate the effects of nuclear deformations and orientations of nuclei in context of ground-state de-excitation of Xe to Gd parents, resulting in a doubly closed shell 100Sn daughter and the complementary clusters. The comparison is also made with spherical choice of fragments to extract exclusive picture of the dynamics involved. Since PCM is based on collective clusterization picture, the preformation and penetration probabilities are shown to get modified considerably by inclusion of the quadrupole deformations (β2i) alone, which in turn affects the decay half-lives of the clusters
Collective clusterization approach to investigate the relevance of deformation effects in Sn radioactivity
The role of deformations and orientations is studied in cluster decays of various radioactive nuclei leading to doubly magic 100Sn or 132Sn daughter nucleus, using the preformed cluster model (PCM). This model treats the cluster emission process via tunnelling across the potential barrier, the cluster/fragment being preformed with a relative probability . With the incorporation of deformation and orientation effects, the fragmentation potential, the penetration path and related barrier characteristics get significantly modified, due to which both the preformation probability and penetrability P of the emitting cluster get influenced. The calculated half-lives of the decaying clusters calculated using PCM are found to be within the upper limits of the present experiments. The influence of deformations and orientations on Sn radioactivity is also seen in terms of various barrier characteristics such as barrier modification, barrier height, etc. Moreover, the role of different nuclear proximity potentials, i.e., Prox 77, Prox 88 and Prox 00, is analyzed in the context of potential energy surfaces (PES) in the ground-state decay of parent nucleus. The behavior of PES is explored including, as well as without including, the shell corrections in the binding energies, which in turn help to explore the importance of doubly magic closed shell configuration of daughter and cluster nuclei. The possible role of higher order multipole deformations (i.e., up to ) is also analyzed in view of the fragmentation path and barrier tunnelling characteristics
Effect of deformations and orientations in 100Sn daughter radioactivity
Based on the preformed cluster model (PCM), we have extended our earlier study to investigate the effects of nuclear deformations and orientations of nuclei in context of ground-state de-excitation of Xe to Gd parents, resulting in a doubly closed shell 100Sn daughter and the complementary clusters. The comparison is also made with spherical choice of fragments to extract exclusive picture of the dynamics involved. Since PCM is based on collective clusterization picture, the preformation and penetration probabilities are shown to get modified considerably by inclusion of the quadrupole deformations (β2i) alone, which in turn affects the decay half-lives of the clusters
Effect of deformations and orientations in 100
Based on the preformed cluster model (PCM), we have extended our earlier study to investigate the effects of nuclear deformations and orientations of nuclei in context of ground-state de-excitation of Xe to Gd parents, resulting in a doubly closed shell 100Sn daughter and the complementary clusters. The comparison is also made with spherical choice of fragments to extract exclusive picture of the dynamics involved. Since PCM is based on collective clusterization picture, the preformation and penetration probabilities are shown to get modified considerably by inclusion of the quadrupole deformations (β2i) alone, which in turn affects the decay half-lives of the clusters
Pressure induced structural, electronic topological, and semiconductor to metal transition in AgBiSe<sub>2</sub>
We report the effect of strong spin orbit coupling inducing electronic topological and semiconductor to metal transitions on the thermoelectric material AgBiSe2 at high pressures. The synchrotron X-ray diffraction and the Raman scattering measurement provide evidence for a pressure induced structural transition from hexagonal (α-AgBiSe2) to rhombohedral (β-AgBiSe2) at a relatively very low pressure of around 0.7 GPa. The sudden drop in the electrical resistivity and clear anomalous changes in the Raman line width of the A1g and Eg(1) modes around 2.8 GPa was observed suggesting a pressure induced electronic topological transition. On further increasing the pressure, anomalous pressuredependence of phonon (A1g and Eg(1)) frequencies and line widths along with the observed temperature dependent electrical resistivity show a pressure induced semiconductor to metal transition above 7.0 GPa in β-AgBiSe2. First principles theoretical calculations reveal that the metallic character of β-AgBiSe2 is induced mainly due to redistributions of the density of states (p orbitals of Bi and Se) near to the Fermi level. Based on its pressure induced multiple electronic transitions, we propose that AgBiSe2 is a potential candidate for the good thermoelectric performance and pressure switches at high pressure
Protein Quality and the Protein to Carbohydrate Ratio within a High Fat Diet Influences Energy Balance and the Gut Microbiota In C57BL/6J Mice
peer-reviewedMacronutrient quality and composition are important determinants of energy balance and the gut microbiota. Here, we investigated how changes to protein quality (casein versus whey protein isolate; WPI) and the protein to carbohydrate (P/C) ratio within a high fat diet (HFD) impacts on these parameters. Mice were fed a low fat diet (10% kJ) or a high fat diet (HFD;
45% kJ) for 21 weeks with either casein (20% kJ, HFD) or WPI at 20%, 30% or 40% kJ. In comparison to casein, WPI at a similar energy content normalised energy intake, increased lean mass and caused a trend towards a reduction in fat mass (P = 0.08), but the protein challenge did not alter oxygen consumption or locomotor activity. WPI reduced HFD-induced plasma leptin and liver triacylglycerol, and partially attenuated the reduction in adipose FASN mRNA in HFD-fed mice. High throughput sequence-based analysis of faecal microbial populations revealed microbiota in the HFD-20% WPI group clustering closely with HFD controls, although WPI specifically increased Lactobacillaceae/Lactobacillus and decreased Clostridiaceae/Clostridium in HFD-fed mice. There was no effect of increasing the P/C ratio on energy intake, but the highest ratio reduced HFD-induced weight gain, fat mass and plasma triacylglycerol, non-esterified fatty acids, glucose and leptin levels, while it increased lean mass and oxygen consumption. Similar effects were observed on adipose mRNA expression,
where the highest ratio reduced HFD-associated expression of UCP-2, TNFa and CD68 and increased the diet-associated
expression of b3-AR, LPL, IR, IRS-1 and GLUT4. The P/C ratio also impacted on gut microbiota, with populations in the 30/
40% WPI groups clustering together and away from the 20% WPI group. Taken together, our data show that increasing the
P/C ratio has a dramatic effect on energy balance and the composition of gut microbiota, which is distinct from that caused by changes to protein quality.KN is supported by the Teagasc Vision Programme on Obesity, which also funded the work detailed in this manuscript. LM is supported by a Teagasc
PhD Walsh Fellowship. HMR is supported by SFI PI (11/PI/1119)