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Tilmicosin (TMC), a semi-synthetic macrolide antibiotic, is widely used in veterinary medicine due to its broad-spectrum, bacteriostatic properties. Frequently administered in various birds species, it is likely used off-label in geese as well. The study sought to investigate TMC's pharmacokinetics, tissue residues, in geese through in vivo experiments. The study involved longitudinal open studies on 15 healthy adult males, with three phases separated by one-month washout periods. Geese were administered TMC through intravenous (IV, 5 mg/kg), subcutaneous (SC, 10 mg/kg), and oral (PO, 25 mg/kg for five consecutive days) routes, with blood samples drawn at specific intervals. Tissue samples were also collected for subsequent analysis at pre-assigned times. TMC in goose plasma was quantified by a fully validated HPLC method. Plasma concentrations were quantified up to 4 hr for the PO and IV routes, and up to 10 hr in the SC route. Significant variations in bioavailability were observed between SC (87%) and PO (4%) routes. The body extraction ratio was low at 0.03, suggesting minimal ability of the liver and kidneys to eliminate TMC. Multiple oral doses showed no plasma accumulation, but tissue data revealed extensive distribution and prolonged residence, up to 120 h, suggesting a sustained therapeutic effect despite the brief plasma half-life. Regarding the multiple PO doses, provisional withdrawal times of 6, 7.5, and 8 days were suggested for the liver, muscles, and kidneys, respectively, according to the MRL set for these matrices in chickens by EMA. In conclusion, while the practical oral administration is discouraged at the population level, SC administration of TMC may be appropriate for geese, albeit impractical for flock therapy., (© 2024 John Wiley & Sons Ltd.)

Topological states of matter possess bulk electronic structures categorized by topological invariants and edge/surface states due to the bulk-boundary correspondence. Topological materials hold great potential in the development of dissipationless spintronics, information storage and quantum computation, particularly if combined with magnetic order intrinsically or extrinsically. Here, we review the recent progress in the exploration of intrinsic magnetic topological materials, including but not limited to magnetic topological insulators, magnetic topological metals, and magnetic Weyl semimetals. We pay special attention to their characteristic band features such as the gap of topological surface state, gapped Dirac cone induced by magnetization (either bulk or surface), Weyl nodal point/line and Fermi arc, as well as the exotic transport responses resulting from such band features. We conclude with a brief envision for experimental explorations of new physics or effects by incorporating other orders in intrinsic magnetic topological materials. [ABSTRACT FROM AUTHOR]

Daptomycin, a lipopeptide comprising an N-decanoyl fatty acyl chain and a peptide core, is used clinically as an antimicrobial agent. The start condensation domain (dptC1) is an enzyme that catalyzes the lipoinitiation step of the daptomycin synthesis. In this study, we integrated enzymology, protein engineering, and computer simulation to study the substrate selectivity of the start condensation domain (dptC1) and to screen mutants with improved activity for decanoyl loading. Through molecular docking and computer simulation, the fatty acyl substrate channel and the protein-protein interaction interface of dptC1 are analyzed. Key residues at the protein-protein interface between dptC1 and the acyl carrier were mutated, and a single-point mutant showed more than three-folds improved catalytic efficiency of the target n-decanoyl substrate in comparing with the wild type. Moreover, molecular dynamics simulations suggested that mutants with increased catalytic activity may correlated with a more "open" and contracted substrate binding channel. Our work provides a new perspective for the elucidation of lipopeptide natural products biosynthesis, and also provides new resources to enrich its diversity and optimize the production of important components., (© 2024 Wiley‐VCH GmbH.)

This article provides a science-based, data-driven perspective on the relevance of the beef herd in the U.S. to our society and greenhouse gas (GHG) contribution to climate change. Cattle operations are subject to criticism for their environmental burden, often based on incomplete information disseminated about their social, economic, nutritional, and ecological benefits and detriments. The 2019 data published by the U.S. Environmental Protection Agency reported that U.S. beef cattle emitted 22.6% of the total agricultural emissions, representing about 2.2% of the total anthropogenic emissions of CO2 equivalent (CO2e). Simulations from a computer model developed to address global energy and climate challenges, set to use extreme improvements in livestock and crop production systems, indicated a potential reduction in global CO2e emissions of 4.6% but without significant enhancement in the temperature change by 2030. There are many natural and anthropogenic sources of CH4 emissions. Contrary to the increased contribution of peatlands and water reservoirs to atmospheric CO2e, the steady decrease in the U.S. cattle population is estimated to have reduced its methane (CH4) emissions by about 30% from 1975 to 2021. This CH4 emission deacceleration of 2.46 Mt CO2 e/yr2 might be even more significant than reported. Many opportunities exist to mitigate CH4 emissions of beef production, leading to a realistic prospect of a 5% to 15% reduction in the short term after considering the overlapping impacts of combined strategies. Reduction strategies include feeding synthetic chemicals that inactivate the methyl-coenzyme M reductase (the enzyme that catalyzes the last step of methanogenesis in the rumen), red seaweed or algae extracts, ionophore antibiotics, phytochemicals (e.g., condensed tannins and essential oils), and other nutritional manipulations. The proposed net-zero concept might not solve the global warming problem because it will only balance future anthropogenic GHG emissions with anthropogenic removals, leaving global warming on a standby state. Recommendations for consuming red meat products should consider human nutrition, health, and disease and remain independent of controversial evidence of causational relationships with perceived negative environmental impacts of beef production that are not based on scientific data. [ABSTRACT FROM AUTHOR]

Microcystins (MCs) are cyclic heptapeptidic toxins produced by many cyanobacteria. Microcystins can be accumulated in various matrices in two forms: a free cellular fraction and a covalently protein-bound form. To detect and quantify the concentration of microcystins, a panel of techniques on various matrices (water, sediments, and animal tissues) is available. The analysis of MCs can concern the free or the total (free plus covalently bound) fractions. Free-form analyses of MCs are the most common and easiest to detect, whereas total-form analyses are much less frequent and more complex to achieve. The objective of this review is to summarize the different methods of extraction and analysis that have been developed for total forms. Four extraction methods were identified: MMPB (2-methyl-3-methoxy-4-phenylbutyric acid) method, deconjugation at basic pH, ozonolysis, and laser irradiation desorption. The study of the bibliography on the methods of extraction and analysis of the total forms of MCs showed that the reference method for the subject remains the MMPB method even if alternative methods and, in particular, deconjugation at basic pH, showed results encouraging the continuation of the methodological development on different matrices and on naturally-contaminated samples. [ABSTRACT FROM AUTHOR]

2D angular correlation of the positron annihilation radiation (2D‐ACAR) spectra are measured for LaB6 along high‐symmetry directions and compared with first‐principles calculations based on density functional theory (DFT). This allows the modeling of the Fermi surface in terms of ellipsoid electron pockets centered at X‐points elongated along the Σ axis (Γ−M direction). The obtained structure is in agreement with quantum oscillation measurements and previous band structure calculations. For the isostructural topologically nontrivial SmB6, the similar ellipsoids are connected through necks that have significantly smaller radii in the case of LaB6. A theoretical analysis of the 2D‐ACAR spectra is also conducted for CeB6 including the on‐site repulsion U‐correction to the local density approximation (LDA+U) of the DFT. The similarities of the 2D‐ACAR spectra and the Fermi surface projections of these two compounds allow to infer that both LaB6 and CeB6 are topologically trivial correlated metals. [ABSTRACT FROM AUTHOR]

Reliable predictions of metabolizable energy (ME) from digestible energy (DE) are necessary to prescribe nutrient requirements of beef cattle accurately. A previously developed database that included 87 treatment means from 23 respiration calorimetry studies has been updated to evaluate the efficiency of converting DE to ME by adding 47 treatment means from 11 additional studies. Diets were fed to growing-finishing cattle under individual feeding conditions. A citation-adjusted linear regression equation was developed where dietary ME concentration (Mcal/kg of dry matter [ DM ]) was the dependent variable and dietary DE concentration (Mcal/kg) was the independent variable: ME = 1.0001 × DE – 0.3926; r 2 = 0.99, root mean square prediction error [ RMSPE ] = 0.04, and P < 0.01 for the intercept and slope. The slope did not differ from unity (95% CI = 0.936 to 1.065); therefore, the intercept (95% CI = −0.567 to −0.218) defines the value of ME predicted from DE. For practical use, we recommend ME = DE – 0.39. Based on the relationship between DE and ME, we calculated the citation-adjusted loss of methane, which yielded a value of 0.2433 Mcal/kg of dry matter intake (DMI ; SE = 0.0134). This value was also adjusted for the effects of DMI above maintenance, yielding a citation-adjusted relationship: CH4, Mcal/kg = 0.3344 – 0.05639 × multiple of maintenance; r 2 = 0.536, RMSPE = 0.0245, and P < 0.01 for the intercept and slope. Both the 0.2433 value and the result of the intake-adjusted equation can be multiplied by DMI to yield an estimate of methane production. These two approaches were evaluated using a second, independent database comprising 129 data points from 29 published studies. Four equations in the literature that used DMI or intake energy to predict methane production also were evaluated with the second database. The mean bias was substantially greater for the two new equations, but slope bias was substantially less than noted for the other DMI-based equations. Our results suggest that ME for growing and finishing cattle can be predicted from DE across a wide range of diets, cattle types, and intake levels by simply subtracting a constant from DE. Mean bias associated with our two new methane emission equations suggests that further research is needed to determine whether coefficients to predict methane from DMI could be developed for specific diet types, levels of DMI relative to body weight, or other variables that affect the emission of methane. [ABSTRACT FROM AUTHOR]

FeSi is known as a narrow-gap semiconductor showing peculiar temperature dependence of transport properties, which evoked debate for over 50 years. In this study, it is shown that the peculiar temperature dependence of the electrical conductivity σ, the Hall coefficient RH, the Hall mobility μH, the Seebeck coefficient S, and the Nernst coefficient Q of FeSi can be well explained in a model that includes the conduction and the valence band with parabolic dispersions together with the top and bottom impurity Hubbard bands. In particular, the coincidence of the hump of σ(T), the maximum of S(T), the minimum of μH(T), and the maximum of Q(T) can be attributed to the contribution from hopping conduction in the top impurity Hubbard band. [ABSTRACT FROM AUTHOR]

Using an iodine‐assisted autoclave technique, europium hexaboride (EuB6) nanowires are successfully prepared. The X‐ray diffraction (XRD) pattern confirms that the obtained black powders are pure‐phase EuB6 crystals. High‐resolution transmission electron microscopy (HRTEM) and selected‐area electron diffraction (SAED) images prove that the EuB6 nanowires are single crystals grown along the [001] direction. From the temperature‐dependent magnetic susceptibility results, EuB6 shows strong susceptibility at low temperature under 15 K, possessing a magnetic momentum of 6.0 μB. An Arrott plot analysis indicates that the Curie temperature TC of ferromagnetic ordering is about 10.1 K. Moreover, the saturated magnetic moment at 7 T and there being no clear hysteresis in the magnetic hysteresis loops suggest that EuB6 is a relatively soft ferromagnet. The electron transport measurements of the nanowire devices reveal that EuB6 nanowires have a lower output current and a higher resistance compared with bulk crystals, and may be useful for the future magnetic devices. [ABSTRACT FROM AUTHOR]

Cyanobacteria of the order Nostocales, including Baltic Sea bloom-forming taxa Nodularia spumigena, Aphanizomenon flosaquae , and Dolichospermum spp., produce resting stages, known as akinetes, under unfavorable conditions. These akinetes can persist in the sediment and germinate if favorable conditions return, simultaneously representing past blooms and possibly contributing to future bloom formation. The present study characterized cyanobacterial akinete survival, germination, and potential cyanotoxin production in brackish water sediment archives from coastal and open Gulf of Finland in order to understand recent bloom expansion, akinete persistence, and cyanobacteria life cycles in the northern Baltic Sea. Results showed that cyanobacterial akinetes can persist in and germinate from Northern Baltic Sea sediment up to >40 and >400 years old, at coastal and open-sea locations, respectively. Akinete abundance and viability decreased with age and depth of vertical sediment layers. The detection of potential microcystin and nodularin production from akinetes was minimal and restricted to the surface sediment layers. Phylogenetic analysis of culturable cyanobacteria from the coastal sediment core indicated that most strains likely belonged to the benthic genus Anabaena. Potentially planktonic species of Dolichospermum could only be revived from the near-surface layers of the sediment, corresponding to an estimated age of 1–3 years. Results of germination experiments supported the notion that akinetes do not play an equally significant role in the life cycles of all bloom-forming cyanobacteria in the Baltic Sea. Overall, there was minimal congruence between akinete abundance, cyanotoxin concentration, and the presence of cyanotoxin biosynthetic genes in either sediment core. Further research is recommended to accurately detect and quantify akinetes and cyanotoxin genes from brackish water sediment samples in order to further describe species-specific benthic archives of cyanobacteria. [ABSTRACT FROM AUTHOR]

Cyanobacteria are well recognised as producers of a wide range of natural compounds that are in turn recognised as toxins that have potential and useful applications in the future as pharmaceutical agents. The order Nostocales, which is largely overlooked in this regard, has become increasingly recognised as a source of toxin producers including Anabaena, Nostoc, Hapalosiphon, Fischerella, Anabaenopsis, Aphanizomenon, Gloeotrichia, Cylindrospermopsis, Scytonema, Raphidiopsis, Cuspidothrix, Nodularia, Stigonema, Calothrix, Cylindrospermum and Desmonostoc species. The toxin compounds (i.e., microcystins, nodularin, anatoxins, ambiguines, fischerindoles and welwitindolinones) and metabolites are about to have a destructive effect on both inland and aquatic environment aspects. The present review gives an overview of the various toxins that are extracted by the order Nostocales. The current research suggests that these compounds that are produced by cyanobacterial species have promising future considerations as potentially harmful algae and as promising leads for drug discovery. The cyanobacteria are well recognized as producers of a wide range of toxin compounds that have useful application in the future as pharmaceutical agents. The present review gives an overview of the various toxins (i.e., microcystins, nodularin, anatoxins, ambiguines, fischerindoles, and welwitindolinones) extracted by the Nostocales. Table 1 shows toxins and toxin‐producing strains, application, molecular formula, mechanism of action, and structure of toxins [ABSTRACT FROM AUTHOR]

The manifestation of the structural and magnetic properties of Co substituted TiFe2 is investigated using powder X-ray diffraction, magnetization and density functional theory calculations. The alloys TiFe2 and TiFeCo crystallize in the hexagonal structure (P63/mmc) with a reduction in the lattice parameters of TiFeCo (by about 0.51% in a and 0.64% in c) when compared to TiFe2. On the other hand, TiCo2 crystallizes in the cubic structure (Fd3¯m). A structural transition from hexagonal to cubic is anticipated for a composition with x ∈ [0.5, 1]. The non-collinear antiferromagnetic (AFM) spin structure (formed by 6h Fe atoms) of TiFe2 with Néel temperature TN ∼ 275 K is reported at zero magnetic field H. Meanwhile, a magnetic field-induced collinear antiferromagnetic spin structure is suggested by magnetization measurements and supported by density functional theory calculations. The magnetization of TiFeCo shows a weak-ferromagnetic (FM)-like transition around 204 K, followed by a broad hump at 85.5 K and H = 200 Oe. Ferromagnetic interactions are weakened, causing the hump to disappear due to the possible transfer of electrons between Fe and Co. TiCo2 shows compensated ferrimagnetism with magnetization of the order of 10−5μB f.u.−1 and a linear increase of M with H at 5 K. The presence of a non-collinear AFM spin structure in TiFe2, a reduced magnetic moment in TiFeCo due to the charge transfer between Co and Fe, and compensated ferrimagnetism in TiCo2 promise a rich phase diagram of Ti(Fe1−xCox)2 alloys and the possible potential of these alloys for use in spintronics applications. [ABSTRACT FROM AUTHOR]

Lanthanide hexaborides (LnB6) have disparate and often anomalous properties, from structurally homogeneous mixed valency, to superconductivity, spectral anomalies, and unexplained phase transitions. It is unclear how such a diversity of properties may arise in the solids of identical crystal structures and seemingly very similar electronic structures. Building on our previous model for SmB6 (mixed valent, with a peak in specific heat, and pressure induced magnetic phase transitions), we present a unifying dynamic bonding model for LnB6 that explains simultaneously EuB6 (possessing an anomalous peak in specific heat at low T, magnetic phase transitions, and no mixed valency), YbB6 (mixed valent topological insulator), and rather ordinary LaB6. We show that Ln can engage in covalent bonding with boron, and, in some members of the LnB6 family, also easily access alternative bonding states through the electron–phonon coupling. The accessibility, relative energetics, and bonding nature of the states involved dictate the properties. [ABSTRACT FROM AUTHOR]

We investigated the molecular and cellular basis of severe combined immunodeficiency (SCID) in six patients with otofaciocervical syndrome type 2 who failed to attain T cell reconstitution after allogeneic hematopoietic stem cell transplantation, despite successful engraftment in three of them. We identified rare biallelic PAX1 rare variants in all patients. We demonstrated that these mutant PAX1 proteins have an altered conformation and flexibility of the paired box domain and reduced transcriptional activity. We generated patient-derived induced pluripotent stem cells and differentiated them into thymic epithelial progenitor cells and found that they have an altered transcriptional profile, including for genes involved in the development of the thymus and other tissues derived from pharyngeal pouches. These results identify biallelic, loss-of-function PAX1 mutations as the cause of a syndromic form of SCID due to altered thymus development. [ABSTRACT FROM AUTHOR]

A model for lattice thermal conductivity in a semiconductor nanowire with a rectangular cross section is investigated. It is based on solving the equations of phonon radiative transfer taking into account interface scattering and modification of the acoustic phonon dispersion. From the numerical calculations, we predict a decrease by an order of magnitude of the lattice thermal conductivity of a 10-nm-thick and 20-nm-wide rectangular nanowire. The interface scattering and phonon confinement play important roles in the reduction of lattice thermal conductivity. The nanowire lattice thermal conductivity is found to decrease with increasing temperature at moderate and high temperatures. It is shown that the phonon confinement becomes more important than interface scattering in the highly specular scattering case. The effect of interface roughness scattering and phonon confinement on the lattice thermal conductance in a rectangular wire at low temperature is also examined. We calculate the contribution to the lattice thermal conductance due to the longitudinal mode for the catenoid contact. It is found that phonon confinement leads to a significant decrease of the lattice thermal conductance at sufficiently low temperatures (T < 0.1 K). [ABSTRACT FROM AUTHOR]

The size effect on thermal conductivity of a free-standing wire with rectangular cross-section is investigated. The electronic thermal conductivity is calculated within a Boltzmann transport equation approach. A simple expression for the reduction in conductivity due to the increase of boundary scattering is presented. The values of thermal conductivity deduced from our calculation are in good agreement with the experimental data for sodium and gold nanowires. The lattice thermal conductivities of silicon (Si) and cadmium telluride (CdTe) nanowires are examined on the basis of the equations of phonon radiative transfer. The calculated thermal conductivities of Si nanowires with square cross-section are found to be in good agreement with molecular dynamics results. The Umklapp and boundary scattering limited lattice thermal conductivities of CdTe nanowires are investigated theoretically by taking into account acoustic phonon dispersion. It is found that the thermal conductivity of nanowires decreases with decreasing side length. It is shown that this decrease of conductivity in wires is smaller than that of a film or a single layer of a superlattice with out-of-plane heat flux, but larger than in the case of in-plane heat flux. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Employing the Monte Carlo method and the exact diagonalization method, we have investigated the magnetic and thermal properties of the magnetic polaron system near the magnetic transition temperature. We have found that the peaks of the magnetic susceptibility and the specific heat, TC and TP, appear at different positions and the percolation of the magnetic polarons occurs near TP. We have also demonstrated that these behaviors are robust in the presence of the external magnetic field. [ABSTRACT FROM AUTHOR]

Raman spectroscopy of many metal hexaborides is well understood for vibrations of Pm3¯m symmetry that can be ascribed to the breathing and deforming modes of boron octahedral clusters at the corners of the cubic unit cell. However, the significance of the lower energy modes has been subject to debate wherein interpretation is dependent on "rattling" of the metal ion within the boron cage or on alternative mechanisms such as the presence of defects or of isotope clusters. Furthermore, converged calculations of phonon dispersions (PDs) using Density Functional Theory (DFT) for YB6 with Pm3¯m symmetry in the published literature are limited and equivocal. Converged PDs across all reciprocal lattice orientations are an important indicator of thermodynamic stability for a phase. We use this criterion to evaluate symmetry conditions for hexaboride structures and compare DFT models of PDs with Raman spectra for the hexaborides BaB6, LaB6, and YB6. We demonstrate that models with lower symmetry using a P4/mmm superlattice along one primary axial direction allow the lower energy modes to be assigned to a point symmetry. This approach, which models displacements of the metal position along the superlattice direction, results in a convergent PD for YB6, an outcome difficult to achieve with Pm3¯m symmetry. Density Functional Theory calculations of phonon dispersions for YB6 show that a lower symmetry P4/mmm superlattice is convergent. This study of metal hexaborides demonstrates that metal atom displacements either side of the centroid in the boron cage generate low wavenumber peaks in Raman spectra. [ABSTRACT FROM AUTHOR]

In order to understand the anomalous magnetic and transport properties of a low carrier density magnetic system EuB6, the magnetic polaron model has been explored with the strong interaction between charge carriers and local magnetic moments. The role of lattice degrees of freedom and the localization effect due to impurity are also studied through the mean-field approximation and the Monte Carlo method incorporating the exact diagonalization. It has been shown that the metal-insulator transition near magnetic transition in EuB6 is naturally understandable in the framework of the magnetic polaron model. [ABSTRACT FROM AUTHOR]

This review is an in-depth survey of the reported synthetic approaches for the preparation of racemic α-amino esters via the reduction of α-nitro or α-oxime ester intermediates. Accordingly, it describes the many pathways that have been designed to prepare such intermediates. This includes synthesis starting with α-nitroacetates, dialkyl malonates, acetoacetates, diethyl oxalates as well as [2+3] or [2+4] cycloadditions using, respectively, alkyl carbonocyanidate N-oxides or alkyl 2-nitrosoacrylates. This review also contains the description of a myriad of side reactions which can occur when working with α-nitro esters. 1 Introduction 2 α-Amino Esters from α-Nitroacetates via Condensation Reactions 3 α-Amino Esters via C-Alkylation or C-Arylation of α-Nitroacetates 4 α-Amino Esters from α-Nitroacetates Using Other Reactions 5 Synthesis of α-Amino Esters via α-Oxime Esters 6 Synthesis of α-Amino Esters via [2+3] Cycloadditions 7 Synthesis of α-Amino Esters via [2+4] Cycloadditions 8 On the Reduction of α-Oxime Esters 9 Conclusion. [ABSTRACT FROM AUTHOR]