Homogeneous Liquid-Liquid Extraction Method for Selective Separation and Preconcentration of Trace Amounts of Palladium

Abstract: A simple and effective homogeneous liquid-liquid extraction method for selective separation, preconcentration and spectrophotometric determination of palladium(II) ion was developed by using a ternary component system (water / tetrabutylammonium ion (TBA -2 mol L -1 and pH= 3.0), a preconcentration factor 10 was obtained for 10 mL of sample. The analytical curve was linear in the range of 2-100 ng mL -1 and the limit of detection was 0.4 ng mL -1 . The relative standard deviation was 3.2% (n=10). Accuracy and application of the method was estimated by using test samples of natural and synthetic water spiked with different amounts of palladium(II) ion. The method is very simple and inexpensive

Feasibility studies for imaging e+^{+}e−^{-} annihilation with modular multi-strip detectors

Studies based on imaging the annihilation of the electron (e$^{-}$) and its antiparticle positron (e$^{+}$) open up several interesting applications in nuclear medicine and fundamental research. The annihilation process involves both the direct conversion of e$^{+}$e$^{-}$ into photons and the formation of their atomically bound state, the positronium atom (Ps), which can be used as a probe for fundamental studies. With the ability to produce large quantities of Ps, manipulate them in long-lived Ps states, and image their annihilations after a free fall or after passing through atomic interferometers, this purely leptonic antimatter system can be used to perform inertial sensing studies in view of a direct test of Einstein equivalence principle. It is envisioned that modular multistrip detectors can be exploited as potential detection units for this kind of studies. In this work, we report the results of the first feasibility study performed on a e$^{+}$ beamline using two detection modules to evaluate their reconstruction performance and spatial resolution for imaging e$^{+}$e$^{-}$ annihilations and thus their applicability for gravitational studies of Ps

Polysaccharide-based hydrogels: properties, advantages, challenges, and optimization methods for applications in regenerative medicine

In the past few years, research has focused on design and development of natural polymers-based hydrogels owing to their inherent features as well as numerous application ranges. In this context, polysaccharide-based hydrogels have attracted significant interest mainly due to their superior physicochemical and biological characteristics. However, these types of biomaterials ‘suffer’ from some problems. This review aims to give an update of diverse optimization strategies used to improve the physicochemical and biological properties of hydrogels based on natural polysaccharides as biomaterials for regenerative medicine applications.SCOPUS: re.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

Marine Bacteria versus Microalgae: Who Is the Best for Biotechnological Production of Bioactive Compounds with Antioxidant Properties and Other Biological Applications?

International audienceNatural bioactive compounds with antioxidant activity play remarkable roles in the prevention of reactive oxygen species (ROS) formation. ROS, which are formed by different pathways, have various pathological influences such as DNA damage, carcinogenesis, and cellular degeneration. Incremental demands have prompted the search for newer and alternative resources of natural bioactive compounds with antioxidant properties. The marine environment encompasses almost three-quarters of our planet and is home to many eukaryotic and prokaryotic microorganisms. Because of extreme physical and chemical conditions, the marine environment is a rich source of chemical and biological diversity, and marine microorganisms have high potential as a source of commercially interesting compounds with various pharmaceutical, nutraceutical, and cosmeceutical applications. Bacteria and microalgae are the most important producers of valuable molecules including antioxidant enzymes (such as superoxide dismutase and catalase) and antioxidant substances (such as carotenoids, exopolysaccharides, and bioactive peptides) with various valuable biological properties and applications. Here, we review the current knowledge of these bioactive compounds while highlighting their antioxidant properties, production yield, health-related benefits, and potential applications in various biological and industrial fields

Machine learning-based event recognition in SiFi Compton camera imaging for proton therapy monitoring

Objective. Online monitoring of dose distribution in proton therapy is currently being investigated with the detection of prompt gamma (PG) radiation emitted from a patient during irradiation. The SiPM and scintillation Fiber based Compton Camera (SiFi-CC) setup is being developed for this aim. Approach. A machine learning approach to recognize Compton events is proposed, reconstructing the PG emission profile during proton therapy. The proposed method was verified on pseudo-data generated by a Geant4 simulation for a single proton beam impinging on a polymethyl methacrylate (PMMA) phantom. Three different models including the boosted decision tree (BDT), multilayer perception (MLP) neural network, and k-nearest neighbour (k-NN) were trained using 10-fold cross-validation and then their performances were assessed using the receiver operating characteristic (ROI) curves. Subsequently, after event selection by the most robust model, a software based on the List-Mode Maximum Likelihood Estimation Maximization (LM-MLEM) algorithm was applied for the reconstruction of the PG emission distribution profile. Main results. It was demonstrated that the BDT model excels in signal/background separation compared to the other two. Furthermore, the reconstructed PG vertex distribution after event selection showed a significant improvement in distal falloff position determination. Significance. A highly satisfactory agreement between the reconstructed distal edge position and that of the simulated Compton events was achieved. It was also shown that a position resolution of 3.5 mm full width at half maximum (FWHM) in distal edge position determination is feasible with the proposed setup

An overview on the role of microalgal metabolites and pigments in apoptosis induction against copious diseases

Presently, researches are oriented towards the management of health and the environment to prevent various dreadful diseases. Recently, natural products from different biological resources are gaining attention due to them being harmless, non-toxic, renewable, sustainable, and biodegradable. Microalgae, the unicellular eukaryotic photosynthetic organisms, are considered as the drug houses of various illnesses recently due to the ease of availability and cultivation. They are sumptuous as they harbor several functional biomolecules including polysaccharides, fatty acids, proteins, secondary metabolites, essential amino acids, vitamins, enzymes, and pigments, and are investigated globally for biological activities and subjected to nutraceutical and pharmaceutical purposes. Apoptosis is a process of programmed cellular disruption induced by external signals or internal activities which causes suppression of inflammation from varied infections. Inhibition of apoptosis might be a major cause for several cancers, autoimmune diseases, and viral infections. In this context, researchers mainly focused on the constituents derived from microalgae to investigate their roles in inducing apoptotic pathways as a mechanism to fight against cancers, cardiovascular, and neurodegenerative diseases. This review sheds light on how these metabolites target the cellular pathways and explores the ideas of utilizing such natural components as major treatment regimens for preventing the diseases examined.SCOPUS: re.jDecretOANoAutActifinfo:eu-repo/semantics/publishe

Characterization of novel CD19-specific VHHs isolated from a camelid immune library by phage display

Abstract Background Monoclonal antibody (mAb)-based immunotherapies have achieved promising outcomes in the treatment of immunological and oncological indications. CD19 is considered one of the most qualified antigens in the treatment of B-cell neoplasms. VHHs (nanobodies) are known for their physicochemical advantages over conventional mAbs rendering them suitable therapeutics and diagnostic tools. Herein, we aimed to isolate CD19-specific VHHs from a novel immune library using phage display. Methods An immune VHH gene library was constructed. Using phage display and after five biopanning rounds, two monoclonal CD19-specific VHHs were isolated. The selected VHHs were expressed, purified, and characterized in terms of their affinity, specificity, sensitivity, and ability to target CD19-positive cell lines. Moreover, in silico analyses were employed for further characterization. Results A VHH library was developed, and because the outputs of the 4th biopanning round exhibited the most favorable characteristics, a panel of random VHHs was selected from them. Ultimately, two of the most favorable VHHs were selected and DNA sequenced (designated as GR37 and GR41). Precise experiments indicated that GR37 and GR41 exhibited considerable specificity, sensitivity, and affinity (1.15 × 107 M−1 and 2.08 × 107 M−1, respectively) to CD19. Flow cytometric analyses revealed that GR37 and GR41 could bind CD19 on the surface of cell lines expressing the antigen. Moreover, in silico experiments predicted that both VHHs target epitopes that are distinct from that targeted by the CD19-specific single-chain variable fragment (scFv) FMC63. Conclusion The selected VHHs can be used as potential targeting tools for the development of CD19-based immunotherapeutics

Directional capacity of human mesenchymal stem cells to support hematopoietic stem cell proliferation in vitro

Objectives: Hematopoietic stem cells (HSCs) reside in a specialised microenvironment in the bone marrow, which is majorly composed of mesenchymal stem cells (MSCs) and its' derivatives. This study aimed to investigate the regulatory role of MSCs to decipher the cellular and humoral communications on HSCs' proliferation, self-renewal, and differentiation at the transcriptomic level. Materials and Methods: Microarray assay was employed to analyse the gene expression profile of HSCs that imparted by MSCs during co-culture. Results: The proliferation of human umbilical cord blood-derived HSCs (hUC-HSCs) markedly propagated when MSCs were used as the feeder layer, without disturbing the undifferentiated state of HSCs, and reduced the cell death of HSCs. Upon co-culture with MSCs, the global microarray analysis of HSCs disclosed 712 differentially expressed genes (DEGs) (561 up-regulated and 151 down-regulated). The dysregulations of various transcripts were enriched for cellular functions such as cell cycle (including CCND1), apoptosis (including TNF), and genes related to signalling pathways governing self-renewal, as well as WNT5A from the Wnt signalling pathway, MAPK, Hedgehog, FGF2 from FGF, Jak-STAT, and PITX2 from the TGF-β signalling pathway. To concur this, real-time quantitative PCR (RT-qPCR) was utilised for corroborating the microarray results from five of the most dysregulated genes. Conclusion: This study elucidates the underlying mechanisms of the mitogenic influences of MSCs on the propagation of HSCs. The exploitation of such mechanisms provides a potential means for achieving larger quantities of HSCs in vitro, thus obviating the need for manipulating their differentiation potential for clinical application