Liquid–liquid extraction of uranium(VI) from weak sodium acetate medium using 2-octylaminopyridine: real sample analysis

Journal of Radioanalytical and Nuclear Chemistry - The analytical technique has been developed for the extraction and determination of uranium(VI). This process is based on the ion-pair complex...     

Oxidovanadium (IV) and iron (III) complexes with O2N2 donor linkage as plausible antidiabetic candidates: Synthesis,structural characterizations,glucose uptake and model biological media studies

With the upsurging cases of type II diabetic patients, the demand for safe and effective oral antidiabetic drugs is also increasing. Coordination complexes have proven their mettle as efficient oral drug candidates, which thereby motivated us in this work to design new transition metal complexes as plausible candidates for the treatment of diabetes. A reduced salen ligand, {H₂(hpdbal)₂-an} ( 1 ) derived vanadium (IV) and iron (III) complexes, namely, [V^IVO{(hpdbal)₂-an}] ( 2 ) and [{Fe^III (OH₂)((hpdbal)₂-an)}₂ μ₂-SO₄] ( 3 ) were synthesized in this study. The newly obtained ligand and complexes were characterized using usual analytical and spectroscopic techniques. The potential of these compounds in inducing increased glucose uptake by diabetic cells were studied by using insulin resistant HepG2 cells as model diabetic cells and 2-NBDG molecule as a D-glucose analogue and fluorescent tracker. The cells added with the vanadium (IV) complex 3 induced significant NBDG uptake of 95.4% which was higher than that induced by metformin, the standard antidiabetic drug. To elucidate the behavior of the complexes in biological media, model solution studies were conducted with a wide range of pH conditions and protein bovine serum albumin (BSA). The complexes demonstrated effective binding with BSA which was concluded through spectroscopic titration studies and were also found to be sufficiently stable over physiological pH conditions. The study can thus prove to be beneficial in the quest for new antidiabetic drugs.     

Linchpins empower promiscuous electrophiles to enable site-selective modification of histidine and aspartic acid in proteins

The conservation of chemoselectivity becomes invalid for multiple electrophilic warheads during protein bioconjugation. Consequently, it leads to unpredictable heterogeneous labeling of proteins. Here, we report that a linchpin can create a unique chemical space to enable site-selectivity for histidine and aspartic acid modifications overcoming the pre-requisite of chemoselectivity.

Linchpin-enabled promiscuous electrophile uncovers an unchartered reactivity landscape for the precision engineering of proteins.     

Investigation of factors influencing the performance of nanofluid-based direct absorption solar collector using Taguchi method

Journal of Thermal Analysis and Calorimetry - The performance of nanofluid-based solar collector depends on different factors like nanoparticle material, base fluid, mass fraction of nanoparticles,...     

Global intercompany assessment of ICIEF platform comparability for the characterization of therapeutic proteins

An international team spanning 19 sites across 18 biopharmaceutical and in vitro diagnostics companies in the United States, Europe, and China, along with one regulatory agency, was formed to compare the precision and robustness of imaged CIEF (ICIEF) for the charge heterogeneity analysis of the National Institute of Standards and Technology (NIST) mAb and a rhPD-L1-Fc fusion protein on the iCE3 and the Maurice instruments. This information has been requested to help companies better understand how these instruments compare and how to transition ICIEF methods from iCE3 to the Maurice instrument. The different laboratories performed ICIEF on the NIST mAb and rhPD-L1-Fc with both the iCE3 and Maurice using analytical methods specifically developed for each of the molecules. After processing the electropherograms, statistical evaluation of the data was performed to determine consistencies within and between laboratory and outlying information. The apparent isoelectric point (pI) data generated, based on two-point calibration, for the main isoform of the NIST mAb showed high precision between laboratories, with RSD values of less than 0.3% on both instruments. The SDs for the NIST mAb and the rhPD-L1-Fc charged variants percent peak area values for both instruments are less than 1.02% across different laboratories. These results validate the appropriate use of both the iCE3 and Maurice for ICIEF in the biopharmaceutical industry in support of process development and regulatory submissions of biotherapeutic molecules. Further, the data comparability between the iCE3 and Maurice illustrates that the Maurice platform is a next-generation replacement for the iCE3 that provides comparable data.     

Structural Determination of an Unusual CuI-Porphyrin-π-Bond in a Hetero-Pacman Cu-Zn-Complex

The synthesis and characterization of a hetero-dinuclear compound is presented, in which a copper(I) trishistidine type coordination unit is positioned directly above a zinc porphyrin unit. The close distance between the two coordination fragments is secured by a rigid xanthene backbone, and a unique (intramolecular) copper porphyrin-π-bond was determined for the first time in the molecular structure. This structural motif was further analyzed by temperature-dependent NMR studies: In solution at room temperature the coordinative bond fluctuates, while it can be frozen at low temperatures. Preliminary reactivity studies revealed a reduced reactivity of the copper(I) moiety towards dioxygen. The results adumbrate why nature is avoiding metal porphyrin-π-bonds by fixing reactive metal centers in a predetermined distance to each other within multimetallic enzymatic reaction centers.     

Thermo-mechanical performance of PVC/ZnO nanocomposites

The present paper deals with the study of thermo-mechanical performance of PVC/ZnO nanocomposites. The samples have been prepared by solution casting technique with different (0, 2, 4, 6 and 8) wt. % of ZnO nanoparticles in poly (vinyl chloride) (PVC) matrix and structurally characterized through scanning electron microscopy. In thermo-mechanical analysis, dynamic mechanical analyzer gives the information about storage modulus and phase transition temperature (T_g). From these viscosities, profile at elevated temperature and activation energy of phase transition can be evaluated. This study reveals that dispersion of nano-ZnO significantly altered the thermo-mechanical properties of neat PVC but the effect is composition-dependent.     

EPR and optical study of Mn-doped bis(l-Asparaginato)Zn(II)

EPR and optical studies of single crystals of Mn²⁺: bis(l-Asparaginato)Zn(II) are reported. The spin-Hamiltonian parameters are determined employing the positions of a large number of resonance lines for various orientations of the external magnetic field. The best-fit zero-field parameters to the observed EPR spectra are obtained as, D=(228±2)×10⁻⁴ cm⁻¹, E=(58±2)×10⁻⁴ cm⁻¹ and a=(−12±1)×10⁻⁴ cm⁻¹,whereas g=2.0002±0.0002, , and . From the optical absorption study, the lattice distortion is suggested. The electron repulsion parameters (B and C) and crystal field parameters (Dq and α) evaluated from the fitting of observed optical spectra are: B=858 cm⁻¹, C=2620 cm⁻¹, Dq=950 cm⁻¹, and α=76 cm⁻¹.