REMOVING THE CADMIUM, ARSENIC AND SULFATE IONS FROM WET PROCESS PHOSPHORIC ACID

Commercially, phosphoric acid is manufactured using different processes. The wet-process is the process applied in Syria using phosphate mineral, and phosphoric acid produced by this process contains a variety of impurities. This paper studies the precipitation of Cd, As and sulfate ions. The results show that the yield of precipitation of sulfate ion increases by increasing the concentration of barium carbonate and temperature. The precipitation of arsenic increases by increasing the concentration of sodium sulfide and temperature. The precipitation of cadmium was better under ambient temperature by sodium sulfide

EXTRACTION OF H3PO4 from Wet Phosphoric Acid By nC4 - nC7 Alcohols

Most phosphate rocks are used to manufacture phosphoric acid by digestion with concentrated sulfuric acid by the wet method. Many impurities dissolve also in the acid and then go to the fertilizer which makes this acid unsuitable for food or pharmaceutical uses. Pure phosphoric acid for food purposes is obtained by reduction of the phosphate rocks in an electric furnace to obtain P2O5 by the dry method. This method consumes a lot of energy and so it is rather expensive. There has been an increased interest in the past few years in purifying commercial wet phosphoric acid to obtain a pure acid. Several methods were developed on the pilot plant or commercial scales but most of the works are still in the developmental stage. This paper studies extraction of H3PO4 by nC4 - nC7 alcohols by liquid-liquid extraction. The alcohol mainly used is n-heptanol. The effect of temperature and mixing time on distribution ratio is studied. The results show that nC7 alcohol is a suitable solvent for H3PO4 extraction. The temperature has a slight negative influence on extraction. The extraction is enhanced by increasing P2O5 and alcohol concentrations. The extraction decreases by increasing the number of carbon atoms or the molecular weight of the n-alcohol, but phase separation is slower. Extraction of uranium and heavy metals is negligible while extraction of fluorine and iron is relatively small

The First Very Long Baseline Interferometry Image of 44 GHz Methanol Maser with the KVN and VERA Array (KaVA)

We have carried out the first very long baseline interferometry (VLBI) imaging of 44 GHz class I methanol maser (7_{0}-6_{1}A^{+}) associated with a millimeter core MM2 in a massive star-forming region IRAS 18151-1208 with KaVA (KVN and VERA Array), which is a newly combined array of KVN (Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry). We have succeeded in imaging compact maser features with a synthesized beam size of 2.7 milliarcseconds x 1.5 milliarcseconds (mas). These features are detected at a limited number of baselines within the length of shorter than approximately 650 km corresponding to 100 Mlambda in the uv-coverage. The central velocity and the velocity width of the 44 GHz methanol maser are consistent with those of the quiescent gas rather than the outflow traced by the SiO thermal line. The minimum component size among the maser features is ~ 5 mas x 2 mas, which corresponds to the linear size of ~ 15 AU x 6 AU assuming a distance of 3 kpc. The brightness temperatures of these features range from ~ 3.5 x 10^{8} to 1.0 x 10^{10} K, which are higher than estimated lower limit from a previous Very Large Array observation with the highest spatial resolution of ~ 50 mas. The 44 GHz class I methanol maser in IRAS 18151-1208 is found to be associated with the MM2 core, which is thought to be less evolved than another millimeter core MM1 associated with the 6.7 GHz class II methanol maser.Comment: 19 pages, 3 figure

Luteinising hormone-releasing hormone analogue reverses the cell adhesion profile of EGFR overexpressing DU-145 human prostate carcinoma subline

Cetrorelix, a luteinising hormone-releasing hormone (LHRH) analogue, has been shown to limit growth of the human androgen-independent prostate cell line DU-145, although other inhibitory actions may also be affected. Both growth and invasion of DU-145 cells are linked to autocrine epidermal growth factor receptor (EGFR) signalling. Invasiveness requires not only cells to migrate to conduits, but also reduced adhesiveness between tumour cells to enable separation from the tumour mass. Thus, we investigated whether Cetrorelix alters the DU-145 cell–cell adhesion and if this occurs via altered EGFR signalling. Pharmacologic levels of Cetrorelix limited the invasiveness of a highly invasive DU-145 subline overexpressing full-length EGFR (DU-145 WT). Extended exposure of the cells to Cetrorelix resulted in increased levels of the cell–cell adhesion complex molecules E-cadherin, α- and β-catenin, and p120. Puromycin blocked the increases in E-cadherin and β-catenin levels, suggesting that de novo protein synthesis is required. The Cetrorelix effect appears to occur via transmodulation of EGFR by a protein kinase C (PKC)-dependent mechanism, as there were no changes in DU-145 cells expressing EGFR engineered to negate the PKC transattenuation site (DU-145 A654); downregulation of EGFR signalling produced a similar upregulation in adhesion complex proteins, further suggesting a role for autocrine signalling. Cetrorelix increased the cell–cell adhesiveness of DU-145 WT cells to an extent similar to that seen when autocrine EGFR signalling is blocked; as expected, DU-145 A654 cell–cell adhesion also was unaffected by Cetrorelix. The increased adhesiveness is expected as the adhesion complex molecules moved to the cells' periphery. These data offer direct insight into the possible crosstalk pathways between the LHRH and EGFR receptor signalling. The ability of Cetrorelix to downregulate EGFR signalling and subsequently reverse the antiadhesiveness found in metastatic prostate cancer highlights a novel potential target for therapeutic strategies

Stripping of Uranium from D2EHPA/TOPO Solvent by Ammonium Carbonate Solutions

Uranium is recovered from phosphoric acid by the D2EHPA/TOPO process. In this process uranium is stripped from the loaded D2EHPA /TOPO solvent in the second cycle by an ammonium carbonate solution. This paper studied stripping of uranium from 0.3 mol/L D2EHPA / 0.075 mol/L TOPO in kerosene by different ammonium carbonate solutions. The ammonium carbonate solutions tested were either prepared locally from ammonia and carbon dioxide gases or commercial and laboratory grades available on the market. A comparison was made between these carbonate solutions in terms of purity, stripping efficiency and phase separation. Both stripping and phase separation were carried out under different conditions of phase ratios and concentrations. The results obtained showed that ammonium carbonate prepared from direct reaction of ammonia and carbon dioxide gases had a high purity and gave the same stripping yield as the laboratory grade. The phase separation was also slightly improved using a pure synthesized ammonium carbonate solution. The phase separation was found to be the best at a concentration of 0.5 mol/L ammonium carbonate solution and at a phase ratio A/O of 1/1 and a temperature of 50 °C. It was possible to obtain > 99\% yield of uranium by operating 2 stripping stages counter-currently under these conditions

Predominantly defective CD8+ T cell immunity to SARS-CoV-2 mRNA vaccination in lung transplant recipients.

BackgroundAlthough mRNA vaccines have overall efficacy preventing morbidity/mortality from SARS-CoV-2 infection, immunocompromised persons remain at risk. Antibodies mostly prevent early symptomatic infection, but cellular immunity, particularly the virus-specific CD8+ T cell response, is protective against disease. Defects in T cell responses to vaccination have not been well characterized in immunocompromised hosts; persons with lung transplantation are particularly vulnerable to vaccine failure with severe illness.MethodsComparison groups included persons with lung transplantation and no history of COVID-19 (21 and 19 persons after initial mRNA vaccination and a third booster vaccination respectively), 8 lung transplantation participants recovered from COVID-19, and 22 non-immunocompromised healthy control individuals after initial mRNA vaccination (without history of COVID-19). Anti-spike T cell responses were assayed by stimulating peripheral blood mononuclear cells (PBMCs) with pooled small overlapping peptides spanning the SARS-CoV-2 spike protein, followed by intracellular cytokine staining (ICS) and flow cytometry for release of cytokines in response to stimulation, including negative controls (no peptide stimulation) and positive controls (phorbol myristate acetate [PMA] and ionomycin stimulation). To evaluate for low frequency memory responses, PBMCs were cultured in the presence of the mRNA-1273 vaccine for 14 days before this evaluation.ResultsIonophore stimulation of PBMCs revealed a less inflammatory milieu in terms of interleukin (IL)-2, IL-4, and IL-10 profiling in lung transplantation individuals, reflecting the effect of immunosuppressive treatments. Similar to what we previously reported in healthy vaccinees, spike-specific responses in lung transplantation recipients were undetectable (< 0.01%) when tested 2 weeks after vaccination or later, but were detectable after in vitro culture of PBMCs with mRNA-1273 vaccine to enrich memory T cell responses. This was also seen in COVID-19-recovered lung transplantation recipients. Comparison of their enriched memory responses to controls revealed relatively similar CD4+ T cell memory, but markedly reduced CD8+ T cell memory both after primary vaccination or a booster dose. These responses were not correlated to age or time after transplantation. The vaccine-induced CD4+ and CD8+ responses correlated well in the healthy control group, but poorly in the transplantation groups.ConclusionsThese results reveal a specific defect in CD8+ T cells, which have key roles both in transplanted organ rejection but also antiviral effector responses. Overcoming this defect will require strategies to enhance vaccine immunogenicity in immunocompromised persons

The teaching/learning content for developing the reading skill at the first stage of basic education

Diplomdarbā tiek aplūkots mācību saturs lasītprasmes attīstīšanai pamatizglītības pirmajā posmā. Lasāmie teksti ir latviešu valodas apguves avots un vienlaicīgi arī iespēja apgūt apkārtējo pasauli. Diplomdarba mērķis ir pētīt un analizēt mācību saturu lasītprasmes attīstīšanai pamatizglītības pirmajā posmā, izstrādāt ieteikumus darba pilnveidošanai. Diplomdarbam ir trīs daļas. 1. daļā analizēta lasītprasmes būtības skaidrojums dažādās teorijās. Otrajā daļā analizēts latviešu valodas mācību saturs skolēna lasītprasmes attīstībai. Trešajā daļā apkopota pieredze, kas gūta analizējot praksi, kā arī piedāvāti ieteikumi lasītprasmes pilnveidošanai. Diplomdarba nobeigumā ir secinājumi un izmantoto avotu sarakstsThe Present Diploma Paper discusses the teaching /learning content for developing the reading skill at the first stage of basic education. The reading texts are the source of the Latvian language learning. The students learn wealth of the native language as well as develop reading skill using the language of communication. The aim of the Diploma Paper is to investigate and analyse the learning content for developing the reading skill at the first stage of basic education, to produce suggestions of the work development. The Diploma Paper contains three chapters. The first chapter focuses on the analysis of various theories of essence of the reading skill. The second chapter analyses the development of the Latvian language content of student’s reading skill. The third chapter deals with the experience of analyzing the practice as well as suggestions of the development of reading skill are provided. The conclusions and bibliography are given at the end of the Diploma Paper

Conversion of Lactobacillus pentosus d-Lactate Dehydrogenase to a d-Hydroxyisocaproate Dehydrogenase through a Single Amino Acid Replacement

The single amino acid replacement of Tyr52 with Leu drastically increased the activity of Lactobacillus pentosus NAD-dependent d-lactate dehydrogenase toward larger aliphatic or aromatic 2-ketoacid substrates by 3 or 4 orders of magnitude and decreased the activity toward pyruvate by about 30-fold, converting the enzyme into a highly active d-2-hydroxyisocaproate dehydrogenase