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Inorganic Chemical Pollutants
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Inhalation of high concentrations of ammonia causes temporary blindness and intolerable irritation of the eyes and the glottis. Large doses of ammonia can actually affect the cerebral energy metabolism in the brain.27 Smaller doses cause irritation of the respiratory tract and conjunctivae. The major hazard of ammonia is to office workers from blueprinting and copying machines, to workers in the chemical industry where larger amounts of ammonia are used in the chemical processes, and to farmers exposed to fertilizers. The TLV for ammonia is 25 ppm, corresponding to about 18 mg/m3.28 Again, this value is probably too high for chronic exposures. Excess ammonia can overload the oxidative deamination mechanisms and create chemical sensitivity, as has been seen in the patients at the EHC-Dallas, giving both reactive airway disease and cerebral dysfunction. The catalytic oxidation of ammonia with atmospheric oxygen gives oxides of nitrogen which can easily be converted to nitric acid (Figure 4.3).
Assessing the performance of Al- and Ga-doped BNNTs for sensing and delivering Cytarabine and Gemcitabine anticancer drugs: a M06-2X study
Published in Molecular Physics, 2023
Hossein Roohi, Mino Rouhi, Ahmad Facehi
CYT and GEM are both drugs used for cancer therapy, specifically for the treatment of pancreatic cancer. CYT is 4-Amino-1-beta-D-arabinofuranosyl-2(1H)-pyrimidinone, while GEM is 4-Amino-1-(3,3-difluoro-4-hydroxy-5-hydroxymethyl)-tetrahydrofuran-2-yl) pyrimidine-2(1H) [54,55]. GEM infusion is a commonly used standard treatment for pancreatic cancer, but it has several significant drawbacks. These include rapid decay, high toxicity, and low efficiency, with only approximately 20% effectiveness. Additionally, GEM has a short half-life in vivo, lasting only about 30 minutes due to decomposition into inactive forms, primarily through deamination in the blood, liver, and kidney. Severe side effects of GEM therapy include anemia or leucopenia in patients. Given these limitations, there is a strong interest in the study of controlled drug release to improve the effectiveness of GEM [56].
Extracellular expression of Saccharomyces cerevisiae’s L-asparaginase II in Pichia pastoris results in novel enzyme with better parameters
Published in Preparative Biochemistry & Biotechnology, 2023
Henrique P. Biasoto, Cristina B. Hebeda, Sandra H. P. Farsky, Adalberto Pessoa, Tales A. Costa-Silva, Gisele Monteiro
L-asparaginase (ASNase - EC 3.5.1.1) catalyzes the deamination of L-asparagine (Asn) to L-aspartate and ammonia. Besides that, as secondary activity hydrolyzes L-glutamine (Gln) in glutamic acid and ammonia (GLNase activity).[1] ASNase is widely known for its use in therapeutics against acute lymphoblastic leukemia (ALL), which is a blood cancer that prevails mostly in children.[2] These neoplastic cells are defective in the synthesis of the amino acid Asn due to low or absent expression of asparagine synthetase gene (ASNS), thus becoming dependent on serum circulating Asn.[3] The administration of ASNase causes a depletion of Asn in the bloodstream, resulting in amino acid starvation that blocks protein synthesis in cancer cells, ultimately leading to failure of cell function and apoptosis. ASNase has become a hallmark in ALL treatment, as upon its introduction in clinical protocols the remission rate increased from 20% to 80%.[4]
Synthesis, structural characterization, and thermal properties of octahedral diperchlorato complexes of copper(II) with the chelating 2-aminomethylpiperidine and 2-aminomethylpyridine ligands
Published in Inorganic and Nano-Metal Chemistry, 2023
The thermal decomposition of metal-amine compounds is the deamination reaction, in one or two steps, depending on the type of the metal ion. Furthermore, the thermal stability also depends on the chelate ring, the base of the ligand, the steric effect, the strength of the M–N bond, and the counter ion.[41] Comparatively, there are not many studies on the effect of ring aromaticity on thermal stability. However, some studies report that due to additional intermolecular π⋯π interactions, the phenyl aromatic ring increases the thermal stability in supramolecular hydrogels,[42] and aromatic interactions increase stability in ternary Cu(II) complexes.[43] The present study reports the synthesis, characterization, thermal and structural properties of two octahedral copper(II)-perchlorato coordination compounds with the chelating AMPp and AMP ligands, respectively. The complexes’ purification and ion exchange have been performed using an SP Sephadex C-25 cation exchanger column (35 × 3 cm).[44] This study can also provide further information for the effect of ring aromaticity on the thermal stability of metal complexes by comparing the thermal stability of the Cu (II) complexes synthesized by the AMPp ligand containing the non-aromatic piperidine ring and the AMP ligand containing the aromatic pyridine ring.