RCP Values Research Articles

MrFeed Pro50 FF supplementation improves growth of Largemouth Bass fed a diet containing 160‐g/kg fish meal

AbstractObjectiveThis study aimed at evaluating the role of a novel commercial product, MrFeed Pro50 FF (MP50), as a functional ingredient with which to formulate low‐fish‐meal diets for Largemouth Bass Micropterus nigricans.MethodsSeven test diets were examined. A reference diet (RD) contained 400‐g/kg fish meal, and a control diet (C) was formulated by replacing 60% of the fish meal in RD with poultry by‐product meal. The other five diets were formulated by adding MP50 to C at 5.0 (D50), 7.5 (D75), 10.0 (D100), 12.5 (D125), or 15.0 (D150) g/kg. Fish (initial body weight = 9.2 ± 0.1 g) were fed the test diets for 8 weeks.ResultThe MP50 supplementation level significantly affected weight gain, final body weight, carbon retention efficiency, energy retention efficiency (ERE), hepatosomatic index (HSI), viscerosomatic index (VSI), the ratio of fish meal consumption to fish production (RCP), and carbon waste. The weight gain of fish fed D50, D75, and D100 was greater than that of fish fed C and D150. The ERE was greater in fish fed D50 and D100 than in fish fed C and D75. The HSI and VSI were greater and nitrogen and carbon wastes were lower for fish fed D50 and D100 than in fish fed C. Fish fed D50, D75, and D100 exhibited greater weight gain and lower RCP values compared with fish fed RD. The weight gain of fish fed RD did not significantly differ from the weight gain of fish fed C, D125, and D150, confirming that the minimum fish meal level could be reduced to 160 g/kg.ConclusionThis study indicates that MP50 at 5.0–10.0 g/kg can be used as a functional ingredient in low‐fish‐meal diets for Largemouth Bass.

Enhancement in Magnetic and Magnetocaloric Properties of CoFe2O4 Nanofibers at Lower Temperatures

AbstractThis research paper investigates new and first insights into the magnetic and magnetocaloric properties of one-dimensional (1D) cobalt ferrite CoFe2O4 (CFO) nanofibers (NFs) fabricated using a sol–gel-based electrospinning technique, focusing in particular on their behavior at low temperatures for specific applications. The microstructural, structural, magnetic, and magnetocaloric properties of the calcined CFO NFs were explored. The microstructure of the NFs, with an average diameter of 210 nm, was examined by scanning and transmission electron microscopy (SEM, TEM). The x-ray diffraction (XRD) of the CFO NFs showed a pure cubic close-packed (ccp) spinel crystalline structure with the Fd$$\overline{3}$$ 3 ¯ m space group. The Raman spectroscopic studies further confirm the cubic inverse spinel phase. The magnetic properties were explored as a function of temperature, ranging from 10 K to 300 K, and ferromagnetic behavior was observed with the highest saturation magnetization of 75.87 emu/g and coercivity of 723 Oe at room temperature. The variation of the magnetic entropy was measured indirectly using the Maxwell approach with an increasing magnetic field. A maximum of $$\left| {\Delta S} \right|$$ Δ S = 1.71 J/K was reached around 32 K. At 180 K, the associated adiabatic temperature change, ΔTmax, was 0.93 K, with a large RCP value of 7.58 J/kg, which is reasonably high for the corresponding nanoparticles (NPs). This work suggests that 1D CFO NFs offer a promising route for the production of nanostructured magnetic materials, potentially impacting various electronic and electromagnetic device applications at low temperatures.

Room-temperature magnetocaloric properties of yLa0.67Ca0.27Sr0.06MnO3/1−yLa0.7Sr0.3Mn0.95Cu0.05O3 composites

In this study, we have characterized the magnetic and magnetocaloric (MC) properties of composites formed by two manganites with appropriate Curie temperatures (TC) and acceptable maximum magnetic entropy change (-ΔSMmax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-\\Delta {S}_{{\ ext{M}}}^{{\ ext{max}}}$$\\end{document}) values. The composites have similar diffraction patterns obtained for the main phases La0.67Ca0.27Sr0.06MnO3 (LCSM) and La0.7Sr0.3Mn0.95Cu0.05O3 (LSMC) overlapping the diffraction peaks of the perovskite structure. The absence of any diffraction peaks distinct from the main phases in the XRD patterns of the composites indicates that there is no third phase besides the main ones. It is understood from the SEM images that the composites are composed of particles of different shapes and that the interparticle spacing decreases and the grain boundaries become clear, indicating that the interaction between particles becomes stronger with the increase of the y ratio. A gradual transition is seen from the M(T) curves, which specify that the composites consist of phases with discrete transition temperatures. The magnetic phase transition of the samples is second order. The -ΔSMmax\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-\\Delta {S}_{{\ ext{M}}}^{{\ ext{max}}}$$\\end{document} value has been calculated as 3.18, 3.24, and 4.05 J kg−1 K−1 at 5 T magnetic field for the composites 0.25LCSM/0.75LSMC, 0.50LCSM/0.50LSMC, and 0.75LCSM/0.25LSMC, respectively. Since the RCP value of 0.5LCSM/0.5LSMC composite is 301.61 J kg−1 under 5 T, it can be considered as a promising candidate for use in various magnetic cooling technologies at room temperature.

Study of magnetic and magnetocaloric properties of calcium doped La0.97−xCaxHo0.03MnO3 compound

This study reports the magnetic and magnetocaloric properties of different concentrations of alkaline earth metal, such as Ca-doped La0.97−xCaxHo0.03MnO3 (x = 0.3, 0.33, and 0.37) composites, which were synthesized via autocombustion technique. The second-order paramagnetic-to-ferromagnetic phase transition temperature appeared at the temperature-dependent field-cooled magnetization curve. The result shows an increase in the Curie temperature of the compound with Ca2+ doping. In addition, increasing the Ca2+ doping concentration further increased the change in magnetic entropy, − ∆SM, up to 0.206 J kg−1 K−1, resulting in a higher RCP value up to 30 J kg−1 at x = 0.37. This work’s key aspect is demonstrating the potentiality of enhancing the magnetocaloric effect in the framework via the spin coupling mechanism of Ca2+-doped rare-earth perovskite compounds.Graphical abstract

Magnetocaloric effect in large temperature window on off-stoichiometric Ni-Mn-Ga-based Heusler alloys

Nickel-Manganese-Gallium-based Heusler alloys have been extensively studied for magnetic cooling applications with different compositions. However, the large hysteresis and narrow range of working temperatures associated with the first-order phase transition make limit their practical application. In this direction, the magnetocaloric effect was analyzed for three different off-stoichiometric compositions of Ni50+y+zMn25+x-yGa25‐x‐z alloys, where x, y, and z vary once at a time. Ni50Mn27Ga23 (NMG 1) and Ni54Mn21Ga25 (NMG 2) samples show large magnetocaloric effects across the second-order ferromagnetic to paramagnetic phase transition. Another sample Ni54Mn25Ga21 (NMG 3) undergoes coupled magneto-structural transition near room temperature with very low hysteresis loss (⁓4 J/kg) and a very high sensitivity of the martensite transition temperature (⁓3.6 K/T) with the field. By cyclic cooling protocol reliable magnetic entropy changes are found to be maxima of − 1.98 ± 0.09, − 1.90 ± 0.11 and − 3.53 ± 0.14 J/kg-K for 3 T field change with large effective RCP values of 235.8 ± 0.1, 161.5 ± 0.1 and 144.7 ± 0.3 J/kg for NMG 1, NMG 2 and NMG 3, respectively. The presence of inter-martensite transition along with the magnetic transition or magneto-structural phase transition widens the range of working temperature which effectively enhances the magnetic cooling performance of these materials. The TC and TM are tuned in Ni-Ga-Mn-based alloys by changing the chemical composition with considering the electron concentrations.

Critical behavior and magnetocaloric effect simulation in TbFeSi and DyFeSi intermetallic compounds using a Landau universal

In this paper, we introduce a novel calculation method of magnetic entropy change in an arbitrary ferromagnetic system based on the Landau model for Gibbs free energy and the Arrott–Noakes equation, −ΔSM=11γ+1dA(T)dTM1γ+1−MS1γ+1+11β+1γ+1dB(T)dTM1β+1γ+1−MS1β+1γ+1−M−MSH1γH1−1γ. This theoretical study was applied to TbFeSi (TFS) and DyFeSi (DFS) intermetallic compounds. First, the critical exponents (β; γ) are found as (0.46; 1.08) and (0.26; 1) for TFS and DFS, respectively. Second, the limitations of the Arrott–Noakes equation in simulating the hole −ΔSM(H, T) curves were discussed. Third, the usefulness of the new method reported earlier predicted large RCP values of around 810 and 779 J kg−1 under a 10 T magnetic field for TFS and DFS samples, respectively.

Radiolysis-Associated Decrease in Radiochemical Purity of 177Lu-Radiopharmaceuticals and Comparison of the Effectiveness of Selected Quenchers against This Process.

The radiolytic degradation of vector molecules is a major factor affecting the shelf life of therapeutic radiopharmaceuticals. The development of time-stable dosage forms of radiopharmaceuticals is the key to their successful implementation in clinical practice. Using [177Lu]Lu-PSMA-617 molecule as an example, the time dependence of the change in radiochemical purity (RCP, %) under radiolysis conditions was studied. The dependence of [177Lu]Lu-PSMA-617 radiolysis on parameters such as time, radionuclide activity, buffer agent concentration, precursor amount, and preparation volume was evaluated. It was shown that the absorbed dose was the dominant factor influencing the RCP. The RCP value is inversely proportional to the absorbed dose in the [177Lu]Lu-PSMA-617 preparation and has an exponential dependence. The lutetium-177 dose factor ψ (Gy·mL·MBq-1) and PSMA-617 concentration-dependent dose constant κ (Gy-1) were evaluated for absorbed dose estimation via computer modeling, chemical dosimetry, and radiochemical purity monitoring under various conditions. The further refinement and application of the dependencies found can be useful for predicting the RCP value at the stage of optimizing the composition of the finished dosage form of therapeutic radiopharmaceuticals. The influence of the buffer agent (sodium acetate) concentration on [177Lu]Lu-PSMA-617 radiolytic degradation was shown and should be considered both when developing a dosage form, and when comparing the results of independent studies. The effectiveness of the addition of various stabilizing agents, such as DMSA, cysteine, gentisic acid, vanillin, methionine, adenine, dobesilic acid, thymine, uracil, nicotinamide, meglumine, and mannitol, in suppressing the effects of radiolysis was evaluated.

Magnetocaloric Effect in LA1.2R0.2CA1.6MN2O7 (R=Tb, Dy, Ho, Er) Perovskites Synthesized by Sol-Gel Method

"Nanocrystalline double layered La1.2R0.2Ca1.6Mn2O7 manganites with R = Tb, Dy, Ho, and Er were synthesized by sol-gel method. The XRD measurements indicate that all samples are single phase with a Sr3Ti2O7-type tetragonal (I4/mmm) structure and mean crystallite sizes between 22 nm and 27 nm. The magnetic measurements evidence a spin-glass like behavior at low temperatures for all samples, which may be due to frustration of random competing ferromagnetic and antiferromagnetic interactions together with the anisotropy originating from the layered structure. A moderate magnetocaloric effect was found for all samples, with the maximum entropy change located at temperatures near the magnetic transition ones, but high RCP(S) values were obtained due to the broadened magnetic entropy curves. Keywords: nanoparticles, double layered perovskite, magnetocaloric effect. "

Development and testing of a survey measure of organizational perinatal patient-centered care culture.

To develop and test a measure of patient-centered care (PCC) culture in hospital-based perinatal care. Data were obtained from US perinatal hospitals: one provided survey development data and 14 contributed data for survey testing. We used qualitative and quantitative methods to develop the mother-infant centered care (MICC) culture survey. Qualitative methods included observation, focus group, interviews, and expert consultations to adapt items from other settings and create new items capturing dimensions of PCC articulated by The Commonwealth Fund. We quantitatively assessed survey psychometric properties using reliability (Cronbach's α and Pearson correlation coefficients) and validity (exploratory and confirmatory factor analysis [CFA]) statistics, and refined the survey. After confirming aggregation suitability (ICCs), we calculated "MICC culture scores" at the individual, unit, and hospital level and assessed associations between scores and survey-collected, staff-reported outcomes to evaluate concurrent validity. Survey development included 12 site-visit observations, one semi-structured focus group (five participants), two semi-structured interviews, five cognitive interviews, and three expert consultations. Survey testing used online surveys administered to obstetric and neonatal unit staff (N=316). Using responses from 10 hospitals with ≥4 responses from both units (n=240), the 20-item MICC culture survey demonstrated reliability (Cronbach's α=0.95) while capturing all PCC dimensions (subscale Cronbach's α=0.72-0.87). CFA showed validity through goodness-of-fit (overall chi-square=214 [p-value=0.012], SRMR=0.056, RMSEA=0.041, CFI=0.97, and TLI=0.96). Aggregation statistics (ICCs < 0.05) justify unit- and hospital-level aggregation. Demonstrating preliminary validity, individual-, unit-, and hospital-level MICC culture scores were associated with all outcomes (satisfaction with care provided, within-unit team effectiveness, and relational coordination [RC] between units) (p-values < 0.05), except for neonatal unit scores and RC (p-value=0.11). The MICC culture survey is a psychometrically sound measure of PCC culture for hospital-based perinatal care. Survey scores are associated with staff-reported outcomes. Future studies with patient outcomes will aid identification of improvement opportunities in perinatal care.

Phase driven magnetic and optoelectronic properties of La2CrNiO6: A DFT and Monte Carlo perspective

In search of the ferromagnetic insulators for spintronic device applications, we have studied the electronic, optical and magnetic properties of La2CrNiO6 (LCNO) using the first principle density functional theory (DFT) and the Monte Carlo simulation technique. Firstly, we have adopted the sol-gel method for the preparation of LCNO and refined the X-ray diffracted value using the Fullprof suite under the Rietveld mechanism. The obtained orthorhombic Pbnm and cubic Fm-3m space groups are used as the input of the DFT calculations. Both the structures have shown the half metallicity and insulting bandgap towards the majority and minority spin direction, respectively. From the magnetic moment calculations, we have seen the low spin state of Ni3+, and the double exchange (DE) interaction are responsible for the ferromagnetic structure of LCNO. The optical dielectric constant is ten, and the refractive index is 3.2 for orthorhombic structure. The transition temperature (TC) is determined to be 110 ​K from the MCS study, which has well agreed with experimental value (111 ​K). The RCP value is determined to 12 ​J/kg with a 5 ​T applied field, which is good for magnetocaloric applications.

Magnetic energy product and magnetocaloric effect in [formula omitted] anti-perovskite nitride material

Anti-perovskite nitride material Fe3AlN is studied by using the density functional theory with generalized gradient approximation (GGA+U) approaches and the Monte Carlo simulation in the framework of the Ising model. The parameter of the unit cell has been optimized, the electronic band structure, the electronic density of states and the magnetic moments of the compound are discussed. Based on the energy calculations, the exchange interactions and the magnetic anisotropy are calculated in order to perform the Monte Carlo simulation. Therefore the obtained Curie temperature Tc=780 (K) of the compound is in agreement with the experimental one Tc=770 (K). The magnetic and magnetocaloric properties are also investigated, the maximum entropy change and the RCP values are 3.355 J/Kg.K and 638 J/Kg for h=5T, respectively. Based on the hysteresis loops, the energy product BH was calculated. The obtained BHmax is equal to 1.26 (MGOe) above the ambient temperature. These results show that the Fe3AlN compound can be a good candidate for both information storage applications and magnetic refrigeration.

Griffiths phase, magnetic memory and ac susceptibility of an antiferromagnetic titanate-based perovskite Er0.9Sr0.1Ti0.975Cr0.025O3 system

In this study, we investigated different physical properties of Er0.9Sr0.1Ti0.975Cr0.025O3 titanate prepared by a solid-state reaction that produces a cubic structure with Fd-3m (227) as a space group. Zero-Field Cooled and Field Cooled measurements show a second-order antiferromagnetic transition at Neel temperature TN = 23 K, and the existence of Griffiths phase at around TGP = 132 K. This soft magnetic material depicts a magnetic memory since it ‘remembers’ its thermal history. The relative cooling power of this titanate-based sample was then measured to be around 292.27 J kg−1 at 5 Tesla and 400 J kg−1 at 6 Tesla. However, these values are lower than the RCP value reported for the most magnetic refrigerant Gd, although these results are high enough compared to different perovskite systems. Therefore, Er0.9Sr0.1Ti0.975Cr0.025O3 is a very suitable, environment-friendly magnetic refrigerant.

Effect of cation substitution on structural, magnetic and magnetocaloric properties of (La0.7Eu0.3)0.75Sr0.25Mn0.9(Me)0.1O3 (Me = Co, Ti)

The paper presents a study of the effect of cation substitution (Co, Ti) → Mn on the structural and magnetic properties, as well as the magnetocaloric effect of the manganite (La0.7Eu0.3)0.75Sr0.25Mn0.9(Me)0.1O3 (Me = Co, Ti). It has been found that both compositions undergo two successive structural phase transitions from the O'-phase (orthorhombic orbitally ordered) to the O-phase (orthorhombic orbitally-disordered) and then to the rhombohedral phase (R-phase) under heating. The difference in the temperature of structural transitions in Co- and Ti-substituted compositions has been accounted for by the competing influence of the steric effect, the charge state, and the specific features of the electronic structure (the Jahn-Teller effect) of cations. The temperature dependence of magnetization reveals that Ti and Co doped compositions exhibit a ferromagnetic (FM) to paramagnetic (PM) transition at TC temperatures of 102 and 165 K, respectively. The correct expression is proposed for the bandwidth W which is proportional to TC. According to the Banerjee criterion, the magnetic phase transitions in (La0.7Eu0.3)0.75Sr0.25Mn0.9(Me)0.1O3 are of the second order. Magnetocaloric effect (MCE) is expanded in the wider temperature range with higher applied magnetic field. For each composition the peak position (Tpeak) of the magnetic entropy change moves to a higher temperature with the increase of magnetic field. Relatively high RCP values are found for both samples.

Study of transport, magnetic and magnetocaloric properties in Sr2+ substituted praseodymium manganite

The magnetotransport, magnetic and magnetocaloric properties in the polycrystalline Pr1−xSrxMnO3 (0.20 ≤ x ≤ 0.40) have been studied. The X-ray diffraction peaks for the composition x = 0.20, 0.33 and 0.40 have been indexed with orthorhombic structure having Pnma space group, whereas x = 0.25 composition has been indexed to R-3c space group having rhombohedral symmetry. The substitution of Sr2+ at Pr3+site shows an increase in metal-insulator transition temperature (TMI) and ferromagnetic ordering temperature (Tc). The composition, x = 0.25 shows the higher isothermal magnetic entropy change, = 2.84 J kg−1K−1 with RCP = 116.33 J kg−1 at ∆H = 3 Tesla. The high RCP value (=151.16 J kg−1) with = 2.41 J kg−1 K−1 at ∆H = 3 Tesla for the composition, x = 0.40, implies that plays a significant role.

Structural and magnetocaloric properties of rare-earth orthoferrite perovskite: TmFeO3

We presented the structural, magnetic, and magnetocaloric data for perovskite TmFeO3. XRD revealed distorted orthorhombic structure (Pbnm) for TmFeO3. Spin-reorientation transition was confirmed through magnetic susceptibility. −ΔSM(max) is 13.72 Jkg-1 K−1 at the temperature of 85 K under ΔH = 6 T, with the RCP value of 676 J/kg. −ΔSM(max) and RCP values were increased with the applied field, possibly due to the d-f exchange interactions. The magnetic hysteresis cycles are established for different values of temperatures. These properties make it a potential candidate used for magnetic refrigerants. For magnetic refrigeration application, very large refrigeration capacity is also required along with large entropy change value.

Effects of Y doping on the magnetic properties and magnetocaloric effect of CeFe2

The magnetic properties and electronic structure of single phase cubic Laves Ce1−xYxFe2 compounds with x ≤ 0.25 are analysed by correlating magnetic measurements with band structure calculations. The Y substitution for Ce stabilizes a ferrimagnetic order in all investigated samples, as indicated by the increase of the spontaneous magnetization values with the decrease of Ce content. The band structure calculations yield negative magnetic moments for the Ce and Y atoms, hence an antiferromagnetic coupling to the Fe magnetic moments. All samples show a second order magnetic phase transition and a roughly linear increase of the transition Curie temperature with Y concentration from 247 K for x = 0.1 to 330 K for x = 0.25. The magnetocaloric effect around the magnetic transition temperature was also investigated and although the maximum value of the magnetic entropy change decreases with increasing yttrium content, large RCP(S) values were obtained for all samples due to the broad ∣ΔSm∣ peaks.

Structural, magnetic, critical behavior and phenomenological investigation of magnetocaloric properties of La0.6Ca0.4−xSrxMnO3 perovskite

Structural, magnetic, critical behavior and magnetocaloric properties of La0.6Ca0.4−xSrxMnO3 (x = 0.0, 0.1 and 0.4) compounds have been investigated. Rietveld refinement of the X-ray diffraction patterns indicates that our samples are pure single phase adopting the rhombohedral structure (R-3c) for x = 0.0 and the orthorombic structure (Pbnm) for x = 0.1 and 0.4. Temperature dependence of magnetization curves exhibit a second order paramagnetic (PM)/ferromagnetic (FM) phase transition at Curie temperature Tc. The critical behavior has been determined through the isothermal magnetization measurements around the critical temperature Tc by means of various techniques such as modified Arrott plot (MAP), Kouvel-Fisher (KF) method and critical isotherm analysis (CIA). The results are fully satisfactory to the requirements of the Widom scaling relation and the universal scaling hypothesis confirming their accuracy. A phenomenological model is applied to describe the magnetocaloric effect (MCE) behavior of compounds under investigation. At $$ \mu_{0} H = 5T $$ , the obtained RCP values stand for about 98, 77 and 68% of that observed in pure Gd for x = 0.0, 0.1 and 0.4, respectively, making of these materials considered as promising candidates for magnetic refrigeration applications near room temperature. By analyzing the field dependence of the magnetic entropy change data as well as the relative cooling power, it was possible to evaluate the critical exponent values which were found not only agree with those deduced from (MAP), (KF) and (CIA) methods, but they also obey the scaling theory. Our findings confirm the good correlation between the critical behavior and the MCE properties in manganite systems.

Room temperature magnetocaloric effect and critical behavior in La0.67Ca0.23Sr0.1Mn0.98Ni0.02O3 oxide

The structural, magnetic and magnetocaloric properties of $${\text{La}}_{0.67} {\text{Ca}}_{0.23} {\text{Sr}}_{0.1} {\text{Mn}}_{0.98} {\text{Ni}}_{0.02} {\text{O}}_{3}$$ nano-crystalline manganite are investigated systematically. The compound is elaborated based on Pechini sol–gel method and then annealed at 1000 °C for 24 h. X-ray powder diffraction shows that, the sample crystallizes in a rhombohedral structure with $$R\overline{3} C$$ space group. A magnetization versus temperature study shows that the compound exhibits a second-order magnetic transition from a ferromagnetic to a paramagnetic state at a Curie temperature $$T_{C}$$ = 296 K. To evaluate the magnetic entropy change $$\Delta S_{M}$$ , we measure the magnetization as a function of temperature and magnetic field. At ambient temperature, we find that $${\text{La}}_{0.67} {\text{Ca}}_{0.23} {\text{Sr}}_{0.1} {\text{Mn}}_{0.98} {\text{Ni}}_{0.02} {\text{O}}_{3}$$ sample has a very important magnetocaloric effect (MCE). In a magnetic field variation of 5 T, this MCE is explained by a maximum of magnetic entropy change $$\left| {\Delta S_{M}^{max} } \right|$$ and a big RCP values at 4.92 $${\text{J}}.{\text{Kg}}^{ - 1} {\text{K}}^{ - 1}$$ and 145 J/kg, respectively, around room temperature (296 K), which give the possibility of technologic application in magnetic refrigeration area. In addition, we find an admirable estimate of the magnetic entropy change, which is based on the Landau theory. Finally, we use the magnetic field dependence of $$\Delta S_{M}$$ to determine the critical exponents of the system and we find that β = 0.39, γ = 1.35, and δ = 4.43, are very close to those predicted to the 3D-Heisenberg model. These results indicate that the present compound is one of candidate materials for magnetic refrigerators near room temperature.

Radiochemical and analytical aspects of inter-institutional quality control measurements on radiopharmaceuticals

BackgroundClinically applied radiopharmaceuticals have to meet quality release criteria like a high radiochemical yield and radiochemical purity. Many radiopharmaceuticals do not have marketing authorization and have no dedicated monograph within the European pharmacopeia, therefore general monographs on quality control have to be applied for clinical applications. These criteria require standardization and validation in labeling and preparation, including QC measurements according to well-defined standard operation procedures. QC measurements however, are often based on detection techniques specific for a certain LC-system. Multi-institutional research and development of new radiopharmaceuticals lead to an increase in multicenter trials. Although all institutes’ radiopharmacies are using the same standardized labeling and operation procedures, they often use different LC and radiodetection systems. Here we present a comparison of QC assessments for 3 radiopharmaceuticals with focus on the interpretation of chromatograms, data-output and potential differences in local practical performances of QC on (U)HPLC.MethodsQC assessments for [111In]In-CCK, [68Ga]Ga-Bombesin and [177Lu]Lu-PSMA analogs were compared. Two of the radiopharmaceutical QC assessments were also applied in other institutes using their own HPLC-systems and concordant software. Data from the HPLC-injections and measurements is processed and summarized in chromatograms, based on a variety of smoothing algorithms for which different software programs are applied. Described radiopeptides were labeled and analyzed according their standardized labeling and operation procedures.ResultsIntegration of main peaks on chromatograms resulted in a range of RCP, depending on the smoothing algorithm used. [111In]In-CCK(A), 68Ga-Bombesin(B) and [177Lu]Lu-PSMA(C) analogs had a RCP range of 88%–96%(A), 89–95%(B) and 92–99%(C) respectively. Important factors affecting final RCP value were site specific background radiation-levels, intrinsic system properties such as noise and sensitivity, personal interpretation e.g. peak-tailing and smoothing algorithms.ConclusionMeasurement of RCP shows a strong method- and system-dependency, even when parameters are validated, standardized and SOP are followed. Release criteria are frequently based on RCP data from one central location. The lack of inter inter institutional validation and standardization in RCP determination makes the results therefore rather arbitrary. For multicenter trials, we recommend to compare locally determined RCP under validated and standardized conditions of in-line activity detection between institutes for each radiopharmaceutical.

Magnetocaloric Effect in La0.67Ba0.33Mn0.95Ni0.05O3 Manganite Near Room Temperature

We report the structural, magnetic, and magnetocaloric properties of La0.67Ba0.33Mn0.95Ni0.05O3 (LBMNO) manganite, synthesized by sol-gel method. X-ray diffraction (XRD) analysis using Rietveld refinement showed that this sample crystallizes in the rhombohedral structure with R $\bar {3}$ c space group. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analysis were used to confirm the structure formation of the LBMNO material. The temperature dependent magnetization data revealed a transition from ferromagnetic (FM) to paramagnetic (PM) phase at $T_{\mathrm {C}}=$ 308 K. Using Arrott plots, it was found that the transition is of a second order. From the measured magnetization data as a function of magnetic applied field, the magnetic entropy change (−ΔSM) and the relative cooling power RCP have been determined. In the vicinity of $T_{\mathrm {C}}$ (−ΔSM) reached a maximum value of 2.15 J kg− 1 K− 1 and a large RCP value of about 299 J kg− 1 under 5 T− 1. This magnetocaloric effect has been analyzed by considering the Landau theory of magnetic phase transition. Consequently, our sample can be considered a promising material in room-temperature magnetic refrigeration.