Contrary to previous studies based on bulk materials, we analyze the behavior of the vibrational density of states (VDOS) and specific heat of an amorphous solid of nano-scales (∼3 nm) at low temperature. With Hamiltonian formulation based on the intermolecular dispersion forces, our analysis indicates a universal semi-circle form of the average VDOS in the bulk of the spectrum along with a super-exponentially increasing behavior in its edge. The latter in turn leads to a specific heat with a superlinear temperature () dependence below< 1even at nano-scales, and, surprisingly agreeing with the experiments although the latter are carried out at macroscopic scales. The omnipresence of dispersion forces at microscopic scales indicates the application of our results to other disordered materials too.
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http://dx.doi.org/10.1088/1361-648X/ac1cb3 | DOI Listing |
Symmetry-breaking spin-state transitions in two of three isostructural salts of MnIII spin-crossover cations, [MnIII(3-OMe-5-NO2-sal2323)]+, with heavy anions are reported. The ReO4- salt undergoes two-step spin crossover which is coupled with a re-entrant symmetry-breaking structural phase transition between a high temperature phase (S = 2, C2/c), an intermediate ordered phase (S = 1/S = 2, P21/c), and a low temperature phase (S = 1, C2/c). The AsF6- complex undergoes an abrupt transition between a high temperature phase (S = 2, C2/c) and a low temperature ordered phase (S = 1/S = 2, P-1).
View Article and Find Full Text PDFFish Physiol Biochem
January 2025
São Paulo State University (UNESP), Aquaculture Center of UNESP, Jaboticabal, Sao Paulo, Brazil.
This study examined the energy-dependent physiological responses, including stress, innate immune, and antioxidant systems, as well as indicators of energy mobilization, in pacu (Piaractus mesopotamicus) exposed to intermittent cold, aiming to assess the correlations between these responses. The fish were acclimated to 28 °C, divided into two groups, a control group maintained at 28 °C, and another exposed to 16 °C for two 24 h periods with a 5-day interval between them. The fish were sampled at six time points: baseline (after acclimatization to 28 °C), 24 h after the 1st exposure to 16 °C, after 5 days of recovery at 28 °C, 24 h after the 2nd exposure to 16 °C, and after 24 and 48 h of recovery at 28 °C.
View Article and Find Full Text PDFMar Biotechnol (NY)
January 2025
Key Laboratory of Efficient Utilization of Non-grain Feed Resources (Co-construction by Ministry and Province) of Ministry of Agriculture and Rural Affairs, Shandong Agricultural University, Taian, Shandong, China.
In China, the red swamp crayfish (Procambarus clarkii), a notorious invasive species, has become an important economic freshwater species. In order to compare the genetic diversity and population structure of crayfish from northern and southern China, we collected 60 crayfish individuals from 4 crayfish populations in northern China and 2 populations in southern China for sequencing using the 2b-RAD technique. Additionally, the whole genome sequence information obtained by 2b-RAD of 90 individuals from 2 populations in northern China and 7 populations in southern China were downloaded from NCBI.
View Article and Find Full Text PDFInorg Chem
January 2025
Institute for Inorganic Chemistry and Center for Sustainable Systems Design (CSSD), Paderborn University, Paderborn 33098, Germany.
A series of Co complexes [Co(ImP)][PF], with HImP = 1,1'-(1,3-phenylene)bis(3-methyl-1-imidazole-2-ylidene)) and R = Me, Et, Pr, Bu, is presented in this work. The influence of the strong donor ligand on the ground and excited-state photophysical properties was investigated in the context of different alkyl substituents at the imidazole nitrogen. X-ray diffraction revealed no significant alterations of the structures and all differences in the series emerge from the electronic structures.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Harvard University, Rowland Institute at Harvard, 02138, Cambridge, UNITED STATES OF AMERICA.
The dynamic response of heterogeneous catalytic materials to their environment opens a wide variety of possible surface states which may have increased catalytic activity. In this work, we find that it is possible to generate a surface state with increased catalytic activity over metallic 2nm Pt nanoparticles by performing a thermal treatment of the CO*-covered Pt catalyst. This state is characterised by its ability to oxidise CO to CO2 at room temperature.
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