Center Of Cage Research Articles

Encapsulating Proton Inside C60 Fullerene: A Density Functional Theory Study on the Electronic Properties of Cationic X+@C60 (X+ = H+, H3O+ and NH4+)

Confining protons into an enclosed carbon cage is expected to give rise to unique electronic properties for both the inner proton and the outer cage. In this work, we systematically investigated the geometric and electronic structures of cationic X+@C60 (X+ = H+, H3O+, and NH4+), and their corresponding neutral species (X = H2O, NH3), by quantum chemical density functional theory calculations. We show that C60 can trap H2O, NH3, H3O+ and NH4+ at the cage center and only slightly influence their geometries. The single proton clings to the inner wall of C60, forming a C-H chemical bond. The encapsulated neutral species almost do not change the electronic structure of the C60, while the internal cations have obvious effects. The charge transfer effect from the inner species to the C60 cage was found for all X@C60 (X = H2O, NH3) (about 0.0 e), X+@C60 (X+ = H3O+, NH4+) (about 0.5 e) and H+@C60 (about 1.0 e) systems. Encapsulating different forms of protons also regulates the fundamental physico-chemical properties of the hollow C60, such as the HOMO-LUMO gaps, infrared spectra, and electrostatic potential, etc., which are discussed in detail. These findings provide a theoretical insight into protons’ applications, especially in energy.

Test Mass Capture Control for Drag-Free Satellite Based on State-Dependent Riccati Equation Method

The drag-free satellite plays an important role in the space-based gravitational wave observatory. The capture control of test mass after release is a crucial technology that can affect the success of the mission. The test mass must be released to the center of the electrostatic suspension cage accurately. This paper presents a nonlinear dynamic model of drag-free satellites in Lagrange formalism. A capture control scheme for test mass release phase is proposed based on the state-dependent Riccati equation (SDRE) strategy. To deal with the actuator saturation problem, a nonlinear saturation model is introduced to the dynamics of satellite, while the SDRE strategy is applied to the non-affine system. The effectiveness of the proposed methodology is verified by the numerical simulation for the drag-free satellite.

Helium roaming in excess electrons in C60F60 as dynamic quasi-Matryoshka dolls.

Multi-guest clathrates exhibit lots of functional characteristics owing to their unique structures, which herald beautiful application prospects, but their fundamental information is still scarce. Herein, we explore a type of (helium, excess electrons/EEs)-C60F60 co-clathrates with quasi-Matryoshka-doll structures using abinitio molecular dynamics simulation and reveal the EEs-entangled He roaming dynamics in C60F60 and its effect on the characteristics of clathrates. Perfluorination ensures that C60F60 possesses an extremely electropositive interior cavity. Its unique confinement effect can stabilize He as an extremely inert entity by noticeably enlarging the 1s-2s orbital gap and can also trap 1-2 EEs in its s-type interior orbital with extremely large binding energies. Co-inclusion of He and EEs in C60F60 exhibits inter-repulsive He⋯EEs entangling dynamics featuring quasi-Matryoshka-doll structures (He@EEs@C60F60). In this structure, EEs screen the attraction of cage-shell Cδ+ to He 1s2 electrons, thus inhibiting their stabilization and orbital expansion, while He conversely decreases the stability of EEs and redshifts their transition absorption. He can roam in the cavity, but its trajectory is impacted by EEs serving as a medium, and thus, the structures exhibit anormal dynamic variation of internuclear He⋯C spin coupling JHeC, which is manipulated by the EEs-entangled He roaming dynamics. JHeC and JHeC' present opposite distance dependences for the colinearly aligned C⋅⋅⋅He⋅⋅⊗⋅⋅⋅⋅⋅C' (⊗, the cage center). This work provides insights into the Matryoshka-doll structured He@EEs@C60F60 with He-EEs entangling dynamics and its modulation on EEs absorption and reveals the dynamic role of EEs in manipulating He-roaming and JHeC coupling properties for promising applications.

RECONSTRUCTION OF PAPROSKY TYPE III ACETABULAR BONE DEFECTS IN REVISION HIP ARTHROPLASTY USING A COMBINATION OF CAGE AND MORSELIZED ALLOGRAFTS

The management of severe acetabular bone defects poses a complex challenge in revision hip arthroplasty. Although biological fixation materials are currently dominant, cage has played an important role in complex acetabular revision in the past decades, especially when a biological prosthesis is not available. The purpose of this study is to report the long-term clinical and radiographic results of Paprosky type Ⅲ acetabular bone defects revised with cage and morselized allografts.We retrospectively analyzed 45 patients who underwent revision hip arthroplasty with cage and morselized allografts between January 2007 and January 2019. Forty-three patients were followed up. There were 19 Paprosky type IIIA bone defect patients and 24 Paprosky type IIIB bone defect patients and 7 patients of the 24 were also with pelvic discontinuity. Clinical assessment included Harris Hip Score (HHS) and Short Form-12 (SF-12). Radiographic assessment included cage stability, allografts incorporation, and center of rotation.All patients were followed up with a mean follow-up of 10.6 years, HHS and SF-12 improved significantly at last follow-up in comparison to the preoperative. There were 2 re-revisions, one at 5 years after surgery, another at 13.6 years after surgery. Two patients had nonprogressive radiolucency in zone III and the junction of zone II and zone III at the bone implant interface. Allografts of 40 (93%) cases incorporated fully.The combination of cage and morselized allograft is an alternative option for acetabular revision with Paprosky type III bone defects with satisfactory long-term follow-up results.

Electronic Structure, Aromaticity, and Magnetism of Minimum-Sized Regular Dodecahedral Endohedral Metallofullerenes Encapsulating Rare Earth Atoms.

A series of minimally sized regular dodecahedron-embedded metallofullerene REC20 clusters (RE = Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, and Gd) as basic units of nanoassembled materials with tunable magnetism and UV sensitivity have been explored using density functional theory (DFT). The contribution of the 4f orbital of the rare earth atom at the center of the C20 cage to the frontier molecular orbital of REC20 gives the REC20 cluster additional stability. The AdNDP orbitals of the four REC20 superatoms that conform to the spherical jellium model indicate that through natural population analysis and spin density diagrams, we observe a monotonic increase in the magnetic moment from Ce to Gd. This is attributed to the increased number of unpaired electrons in the 4f orbitals of lanthanide rare earth atoms. The UV-visible spectrum of REC20 clusters shows strong absorption in the mid-UV and near-UV bands. REC20 clusters encapsulating lanthanide rare earth atoms stand out for their tunable magnetism, UV sensitivity, and stability, making them potential new self-assembly materials.

A passive fish sampling method is representative for size but selective for parasite load

Fish capture in industrial aquaculture is both necessary (i.e., for transfer, monitoring and harvesting) and difficult. The most logistically feasible methods rely heavily on crowding, a process that is detrimental to fish welfare and production outcomes. Jump nets, which rely on passive capture via jumping behaviour, present a welfare-friendly alternative. But reliance on behaviour means capture is not guaranteed, and limited knowledge of their capture rate and sampling biases means they are not yet used to their full potential. Here, in sea-cages stocked with Atlantic salmon Salmo salar, we investigated how capture rate varied with net size, position, and time of day, and if salmon caught via jump net were representative of the sea-cage population. A comparison of jumping rates into surface rings (without nets) indicated that larger jump nets will catch more fish. Capture rate was highest in rings positioned in the centre of cages, and during the morning and evening. Jump nets sampled representatively for fish size but caught salmon with marginally lower condition (<2% difference) and with three times higher parasitic salmon louse (Lepeophtheirus salmonis) loads than fish caught using lift nets. Our results indicate that jump nets can be used as a size-representative sampling tool and to target lice infected salmon for treatment.

Be12B12: A core@cage structure beryllo-borospherene

A new class of beryllium-boron cluster, core@cage structure beryllo-borospherene, is described herein theoretically. The global minimum of Be12B12 cluster is a core@cage configuration with D3 symmetry, one Be atom is positioned at the center of cage, with the cage surface composed of η6-Be atom face-capping a hexagon (a Be atom occupies a Be3B3 hexagon in a face-capping η6 configuration) at both ends (top and bottom) and a jagged Be3B6 ring in the middle. Theoretical analyses reveal that in this system, the Be atom serves as donor for almost two electrons to the B atoms, forming typical electrostatic interactions, while the interaction between the B atoms is mainly covalent interaction. Further theoretical calculations indicate that the core@cage structure Be12B12 exhibits unique polarization properties, nucleophilic and electrophilic reaction site characteristics, and spectral properties. Similar to the magic-size (CdSe)13 and B12N12, Be12B12 is anticipated to yield more exotic properties and further widespread applications.

Dual Stabilization of a Tri-Metallofullerene Radical Er3@C80: Exohedral Derivatization and Endohedral Three-Center Bonding.

The enclosed space within fullerene molecules, capable of trapping metal clusters, offers an opportunity to investigate the behavior of metal atoms in a highly confined sub-nanometer environment. However, the studies on trimetallofullerenes M3@C80 have been very limited due to their difficult obtainability. In this paper, we present a new method for obtaining a tri-metallofullerene Er3@C80 through exohedral modification of the fullerene cage. Our findings reveal that Er3@C80 exhibits a radical character and can react with the dichlorobenzene radical to generate a stable derivative Er3@C80PhCl2. Theoretical calculations demonstrate the presence of a three-center two-electron metal-metal bond in the center of the fullerene cage. This bond serves to counterbalance the Coulomb repulsion between the Er ions. Consequently, both exohedral derivatization and endohedral three-center bonding contribute to the substantial stability of Er3@C80PhCl2. Furthermore, molecular dynamics simulations indicate that the Er3 cluster within the molecule possesses a rigid triangle structure. The availability of M3@C80 derivatives opens avenues for future investigations into interactions among metal atoms, such as magnetic coupling, within fullerene cages.

Oxygen insertion at the cage center: an unconventional tuning strategy for enhancing the photocatalytic performance of atomically precise copper cluster cocatalysts

This work not only confirms the long-standing prediction that the Cu8 center can accommodate an oxygen atom but also demonstrates a novel central atom regulation strategy to obtain highly active copper clusters as photocatalysts.

Minimum-Time Control for the Test Mass Release Phase of Drag-Free Spacecraft

The capture control of test mass by means of the electrostatic suspensions is crucial for drag-free spacecraft. The test mass must be released to the cage center of the inertial sensor accurately and quickly. This paper proposes a minimum-time capture control method for the test mass release phase of drag-free spacecraft. An analytical solution of optimal control is derived based on Pontryagin’s minimum principle and the linearized dynamics model of the test mass during the release phase. The parameters of the analytical solution are initially guessed with an approximate linear solution of the test mass dynamics model and are slightly modified by using differential correction. Compared with the exact numerical solution by the hp -adaptive pseudospectral method, the analytical solution is proved to be minimum-time. Numerical simulation shows that the proposed control method quickly captures the test mass to the cage center of the inertial sensor. The capture time to stabilization is only half that of the traditional controller.

Growth rate, meat yield, condition index and reproduction of mussels (Mytilus galloprovincialis, Lamarck 1819) integrated to a fish farm

In the current study mussels were integrated to a fish farm located at the Aegean Sea, which is providing important production sites for the European aquaculture industry. Growth and survival, meat yield, condition index were calculated and gonad development was observed monthly over a one year period from April 2018–2019. First the impact area of sea cage farm was determined and study carried out at three sitations that were identified as impact zone, sea cage center and distant zone without impact from farm site. Temperature, salinity, chlorophyll-a and particulate matter were measured monthly. It was determined that, the mussel growth of at the impact zone was statistically significant with a final size of 61.36 ± 4.2 mm which was superior than those located in the center point and far distance zone with no influence from the cage farm. The mussels in the study area were in the resting phase during the summer months; became sexually active with the decline in water temperature and spawning occurred during the winter time from December to March.

MP60-20 ROLE OF SHH PATHWAY IN URINARY CONTINENCE AND ITS IMPACT ON CELLULAR FATE IN MOUSE URETHRA

You have accessJournal of UrologyCME1 Apr 2023MP60-20 ROLE OF SHH PATHWAY IN URINARY CONTINENCE AND ITS IMPACT ON CELLULAR FATE IN MOUSE URETHRA Walid Farhat, Priyank Yadav, Marcela Ambrogi, Audrey Spiegelhoff, Chad Vezina, and Kimberly Keil Stietz Walid FarhatWalid Farhat More articles by this author , Priyank YadavPriyank Yadav More articles by this author , Marcela AmbrogiMarcela Ambrogi More articles by this author , Audrey SpiegelhoffAudrey Spiegelhoff More articles by this author , Chad VezinaChad Vezina More articles by this author , and Kimberly Keil StietzKimberly Keil Stietz More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003318.20AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Sonic hedgehog (Shh) signaling is critical in many developing organs and subject to disruption through gene-environment interactions. Urinary continence is dependent on appropriate development of bladder neck and urethra driven by epithelial-mesenchymal interactions mediated in part by SHH. To further understand the impact of Shh pathway disruption on lower urinary tract and continence, we examined voiding physiology and histology in compound mutant GLI family zinc finger Gli2+/−; Gli3Δ699/+ mice, which have hypomorphic hedgehog signaling. METHODS: Voiding physiology was tested in young adult female mice (n=5-8/genotype) using void spot assay, uroflowmetry and ex vivo bladder bath assays. Urethra and bladder (n=3/genotype) were collected for immunostaining using antibodies against smooth muscle alpha actin to visualize urethral smooth muscle thickness, or uroplakin, transformation related protein 63, and keratin 5 (combinatorial staining resolves basal, intermediate and luminal epithelial cells). RESULTS: Gli2+/−; Gli3Δ699/+ female mice void more urine spots, void more spots of smaller diameter and void a greater percentage of urine in the cage center than wild type mice. Voids from Gli2+/−; Gli3Δ699/+ mice, measured by uroflowmetry, weigh less (indicating smaller volume) and are shorter in duration than wild type mice. Gli2+/−; Gli3Δ699/+ female mouse bladders, isolated in ex vivo bath preparations, are less responsive to electrical field stimulation and potassium chloride than bladders from wild type mice. Our results are consistent with detrusor under activity and potential stress incontinence in Gli2+/−; Gli3Δ699/+ female mice. In search for a physiological mechanism, we conducted histological analysis to reveal a clear anatomic boundary between wild type mouse bladder neck and urethra. Umbrella shaped uroplakin+ cells populate the bladder neck and cuboidal shaped uroplakin- superficial cells populate the urethra. The bladder neck epithelium of Gli2+/−; Gli3Δ699/+ mice does not appreciably differ from wild type, but urethral epithelial cells are uroplakin+, suggesting possible segmental deficits during urethral development that may account in part for incontinence in Gli2+/−; Gli3Δ699/+ mice. CONCLUSIONS: Our data suggest that establishing continent voiding function in mice is dependent on appropriate urethra epithelial cell fate. Future work to understand mechanisms underlying decreased bladder contractile properties, and urethral cell fate will enhance understanding of the continence mechanism. Source of Funding: DK104310 © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e851 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Walid Farhat More articles by this author Priyank Yadav More articles by this author Marcela Ambrogi More articles by this author Audrey Spiegelhoff More articles by this author Chad Vezina More articles by this author Kimberly Keil Stietz More articles by this author Expand All Advertisement PDF downloadLoading ...

Superconductivity in Li8Au electride

Located at crystal voids, interstitial anion electrons (IAEs) have diverse topologies, which may be tuned to achieve new properties. Elucidating the role of IAEs in electron-phonon coupling (EPC), and using it to design new electride superconductors, leads to the current prediction of superconducting Li8Au at high pressure. We suggest that the occurence of high-temperature superconductivity in electrides requires high-symmetry structures with hydrogen-like cages, an electron acceptor element to balance charges, and isolated IAEs coupled with medium-frequency vibrations. The uniquely designed Li8Au electride has a NaCl-type (B1) lattice, with atomic Au and cubic Li8 cages as bases. Isolated IAEs are formed at the cage centers, with extra charges taken up by Au. These octahedrally coordinated IAEs have a p-orbital-like attribute and are strongly coupled with atomic vibrations in the Li8 cages. The strong EPC in Li8Au results in a calculated Tc of 73.1 K at 250 GPa, which is the highest Tc reported to date for all the electrides. A slight substitutional Pt doping can enhance the Tc of Li8Au to exceed liquid nitrogen temperature.

Constrained nonlinear high-efficiency model predictive technics for test mass capture

This paper presents a nonlinear high-efficiency model predictive control (NHMPC) with constraints designed for the test mass (TM) capture phase of the drag-free satellite about gravitational wave observatory. To avoid collisions between test mass and satellite cavity, TM capture is the essential technology for drag-free satellite. Test mass is located inside an electrostatic suspension and locked by a clamp mechanism initially. The test masses are released with high initial offsets and velocities when the mechanism is retracted. The purpose of this phase is to guarantee the TM to be positioned at the cage center and attitude aligned with the local cage frame. Due to the low actuation authority of electrostatic suspension along with critical initial offsets and velocities, it is a challenging task to design the attitude and translation control schemes with simultaneous consideration of system performance and energy consumption. For the problem given above, the TM capture can be reformulated into a nonlinear quadratic optimal control problem with the state and input constraints. A nonlinear model predictive control (NMPC) structure is also designed to handle the noises by forming a closed loop. This control framework can realize optimality and robustness in a compromise. To improve the speed of solving high-dimensional nonlinear optimal control online for MPC, the indirect Chebyshev pseudospectral method with constraints is employed. The convergence and stability of the control loop are analyzed. Simulation examples show that the feasibility and performance of the designed control loop are verified compared with the existing methods and computation times in the millisecond range can be achieved.

Pressure-induced superconductivity of Ac-B-H hydrides.

The search for room-temperature superconductors among high-pressure hydrides is a hot research topic. In this study, the structures, stabilities and superconducting properties of ternary Ac-B-H hydrides were studied using a genetic algorithm (GA) combined with density functional theory (DFT) calculations. It was shown that the R3̄m-AcBH8 and I4/mmm-AcB2H8 structures were thermodynamically and dynamically stable above 70 and 125 GPa, respectively. In the R3̄m-AcBH8 structure, the BH6 unit and the dispersed H atoms were bonded to form a corrugated structure. The I4/mmm-AcB2H8 structure contained a cage and the Ac atom located at the cage center. The calculations of the electron-phonon coupling showed that the R3̄m-AcBH8 and I4/mmm-AcB2H8 structures had Tc values of 140 K (70 GPa) and 99 K (125 GPa), respectively. The analyses of the phonon dispersion curves revealed that electron-phonon coupling was closely related to the vibrations of the B-H bonds.

Exploration of the potential energy surface in mixed Zintl clusters applying an automatic Johnson polyhedra generator: the case of arachno E6M24- (E = Si, Ge, Sn; M = Sb, Bi).

A new algorithm called Automatic Johnson Cluster Generator (AJCG) is presented, which, as its name indicates, allows the definition of the desired Johnson polyhedron to subsequently carry out all the possible permutations between the atoms that form this polyhedron. This new algorithm allows the exhaustive study of the structures' potential energy surface (PES). In addition, the AJCG algorithm is helpful for the study of three-dimensional compounds such as boranes or Zintl clusters and their structural derivatives with two or more different atoms. The automatic filling of vertices is particularly useful in mixed compounds because of the possibility of taking into account all possible configurations in the structure. As a test system, we investigated the arachno-type E6M24- (E = Si, Ge, Sn; M = Sb, Bi) structure which has eight vertices and complies with Wade-Mingos rules. Initially, we defined a bipyramidal structure (10 vertices), and filled the vertices with the atoms in all possible configurations. Since the selected system has eight atoms, the two remaining vertices were filled with pseudo atoms to complete the structure. After re-optimizing the initial population generated with AJCG, a large number of isomers with energy below 10 kcal mol-1 are identified. These results show that the most stable isomers possess homonuclear M-M bonds, except Sn6Bi24-. Although the overall putative minima differ at the PBE0-D3 and DLPNO-CCSD(T) levels, they are always competitive minima. In addition to using high-precision methodologies to correctly study relative energies, applying solvent effects in highly charged systems becomes mandatory. The aromatic character of these studied systems was demonstrated qualitatively with two- and three-dimensional mapping and quantitatively by calculating the value of the z-component of the induced magnetic field at the cage center, including scalar and spin-orbit correction for relativistic effects. The compounds studied have a high degree of aromaticity, which allows us to establish that despite structural modifications (i.e., from closo to arachno), the aromaticity is preserved.

Density Functional Theory Calculation of N–H2S Hydrate

This study establishes a high-symmetry water cage structure model (structure N) based on the density functional theory first-principles technique. Three high-symmetry H2S hydrates (N–H2S hydrate) are examined in terms of their geometric structures, electrical characteristics, and optical characteristics. The structure of three N–H2S hydrates is most stable when H2S is in the center of water cage with small hydrogen bonds, and the molecular orientation of H2S has little effect on the structure of hydrate. The energy band of H2S enters forbidden band, resulting in the band gap of N–H2S hydrate being much less than that of water cage. A formation energy of −0.128 eV is reached when H2S DOS shift to the higher energy zone and the water cage DOS shift more to the lower energy region. The three N–H2S hydrates also possess various reflectivity characteristic peaks in the energy range of 5–12.5 eV, which might be exploited for electromagnetic detection of N–H2S hydrates. The findings of this research may serve as a theoretical foundation for related experiments.

Restoration and maintenance of segment lordosis in oblique lumbar interbody fusion

PurposeRestoration of the segment lordosis angle (SLA) can effectively reduce the risk of adjacent segment degeneration. This study aimed to perform a comprehensive multifactor analysis of the risk factors affecting restoration and maintenance of the SLA in oblique lumbar interbody fusion (OLIF).MethodsSeventy-three patients (93 segments) who underwent OLIF with posterior pedicle screw fixation due to lumbar degenerative disease between January 2015 and December 2019 were included. Radiographic parameters including the middle disc height (MDH), segment lordosis angle (SLA), cage center point ratio (CPR), cage subsidence, and L1 CT Hounsfield Unit (HU) were measured.ResultsThe postoperative SLA increased from 3.5° to 8.7°, and decreased to 6.7° at the last follow-up. Multivariate analysis showed that preoperative SLA, CPR and cage subsidence were significantly correlated with SLA restoration. The significant correlations were between restoration of SLA with pre-operative SLA (r=-0.575, adjusted R2 = 0.323, P < 0.01) and between SLA restoration and CPR (r = 0.526, adjusted R2 = 0.268, P < 0.01). Cage subsidence was found in 12.9% (12/93) of segments and was the main factor affecting SLA loss (4.2 ± 1.0° versus 1.7 ± 2.1°, P < 0.01). Logistic regression analysis showed that CPR < 50%, L1 CT HU < 110 and cage height > preoperative MDH were risk factors for cage subsidence. Cages placed anteriorly (CPR ≥ 50%) showed a large SLA increase and lower incidence of cage subsidence than those placed posteriorly (5.9 ± 3.9° versus 4.2 ± 3.2°, P < 0.05; 1.8% versus 28.9%, P < 0.05, respectively).ConclusionSLA restoration is dependent on preoperative SLA, cage subsidence and cage position in OLIF. Cage position is the key determinant of SLA restoration and placement of the cage at the anterior position (CPR ≥ 50%) can achieve better restoration of the SLA and reduce the incidence of cage subsidence.

Theoretical Insights into the Geometrical Evolution, Photoelectron Spectra, and Vibrational Properties of YGe n - (n = 6-20) Anions: From Y-Linked to Y-Encapsulated Structures.

The structural evolution behavior of germanium anionic clusters doped with the rare-earth metal yttrium, YGen– (n = 6–20), has been investigated using a mPW2PLYP density functional scheme and an ABCluster structure searching technique. The results reveal that with increasing cluster size n, the structure evolution pattern is from the Y-linked framework (n = 10–14), where Y serves as a linker (the Y atom bridges two germanium subclusters), to the Y-encapsulated framework (n = 15–20), where the Y atom is located in the center of the Ge cage. The simulated PES spectra show satisfying agreement with the experimental PES spectra for n = 12–20, which reveals that the global minimum structures reported here are reliable. In particular, the anionic YGe16– nanocluster is found to be the most stable structure in the size range of n = 6–20 through analyzes of the relative stability, highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap, spherical jellium model, and isochemical shielding surface. Moreover, spectral properties such as infrared and Raman spectra were reported. In addition, the UV–vis spectra of the YGe16– nanocluster are in good agreement with solar energy distribution, showing that such substances serve as multifunctional building blocks to be potentially used in optoelectronic devices or solar energy converters.

Rib abnormalities and their association with focal dark spots in Atlantic salmon fillets

Focal dark spots (DS) represent the most common quality problem in farmed Atlantic salmon (Salmo salar L.). DS are predominantly located in the cranio-ventral region of the fillet, that is characterized by the presence of ribs. The current study explores the possible association between abnormal rib morphology and DS types and the frequency of rib abnormalities in the rib cage by X-ray imaging. The fish used were salmon from a common smolt group that were sampled in freshwater (smolt farm) and subsequently two, five, eight and 14 months after sea transfer to small-scale land-based tanks or commercial sea-cages. Large size wild salmon were used as additive. Rib abnormalities were found in most fish, with a consistent number of four abnormalities per rib cage side of smolts, land-based and wild salmon. After transfer from freshwater to sea-cages, there was an abrupt increase from four to 10 abnormal ribs per rib cage side, mainly explained by low-density and shorter ribs. The number of abnormal ribs stabilized in further samplings at around eight abnormalities per rib cage side. In contrast to wild salmon, abnormalities in farmed salmon were symmetrically concentrated in the center of the rib cage in mid and distal parts of ribs, where also most DS were concentrated. No typical black DS were observed in smolts, salmon farmed in land-based tanks or wild salmon. Two months after transfer to sea-cages, 15% of the salmon had fillet-red DS, while fillet-black DS were observed five months after sea transfer (30%). The prevalence of fillet-red DS oscillated between 15 and 3% during the seawater phase, while fillet-black DS increased until the eighth month after seawater transfer, stabilizing in further samplings at 43–45%. The prevalence of rib abnormalities was 1.6 times higher in fillet-black DS than in control tissue, and 2 times higher for peritoneum DS, principally because of various forms of bent-, and broken ribs. There was an association between rib abnormalities and DS, although additional factors influenced the final DS phenotype. Preventing damaging incidents in the late smolt phase and sea-cage operations can likely reduce the prevalence of abnormal ribs and DS.