RESUMO
The water body environment is related to ecological and human health. Adsorption is an effective means to remove pollutants from water bodies. Currently, the common adsorbents suffer from disadvantages such as structural instability and poor adsorption performance under acidic conditions, which not only affect the adsorption efficiency but also cause secondary pollution of water bodies. In this study, a novel aminated multiwalled carbon nanotube-doped flower-like nanocomposite was designed, where the anionic or neutral groups were protonated under acidic conditions, and it displayed a higher adsorption capacity for dyes by ion exchange, represented by methylene blue (MB) and rhodamine B (RB). WSe2 in the composite increases its adsorption sites. The adsorption efficiency of pollutants in acidic wastewater was enhanced while avoiding secondary contamination. The synthesized composites showed maximum adsorptions of 27.55 and 27.47 mg/g for MB and RB, respectively. The current work offers a novel approach to treating acidic wastewater.
Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Adsorção , Corantes/química , Humanos , Cinética , Fenômenos Magnéticos , Azul de Metileno/química , Nanotubos de Carbono/química , Águas Residuárias , Água , Poluentes Químicos da Água/análiseRESUMO
Objectives: This research aimed to present a novel glasses-free distance random-dot stereotest system (GFDRDSS) using an eye-tracking method. Methods: A single-view autostereoscopic display applying a backlight control system combined with an eye-tracking method and the corresponding random-dot stereotest software were developed to create a GFDRDSS with a viewing distance of 5 m. The stereoacuity of 12 subjects with normal eye position was evaluated using the Randot Stereotest, Stereoscopic Test Charts vol. 3 (Yan's Charts), Distance Randot® Stereotest, and GFDRDSS. Results: The GFDRDSS could provide distinct and stable glasses-free stereoscopic perception even while the subject was moving their head. It could evaluate binocular disparities of 40-2,400 arcsec. Eleven subjects with normal near visual acuity had fine near stereovision (20-60 arcsec) using the Randot stereotest and Yan's Charts. Under refractive correction, 10 subjects had fine stereovision (≤60 arcsec) using the GFDRDSS at a distance of 5 m, and 9 had fine stereovision using the Distance Randot® Stereotest at 3 m. Other subjects described the 100 arcsec-level stereograms correctly. The results exhibited a concordance of stereoacuity within one degrade between the two distance stereotests. Conclusion: The proposed GFDRDSS can alternately project a couple of random-dot stereograms to the subjects' eyes and provide a glasses-free distance stereotest, which showed good concordance with the Distance Randot® Stereotest. More data are needed for statistical studies.
RESUMO
Amyloid precursor protein (APP) cleaving enzyme (BACE) is the enzyme responsible for beta-site cleavage of APP, leading to the formation of the amyloid-beta peptide that is thought to be pathogenic in Alzheimer's disease (AD). Hence, BACE is an attractive pharmacological target, and numerous research groups have begun searching for potent and selective inhibitors of this enzyme as a potential mechanism for therapeutic intervention in AD. The mature enzyme is composed of a globular catalytic domain that is N-linked glycosylated in mammalian cells, a single transmembrane helix that anchors the enzyme to an intracellular membrane, and a short C-terminal domain that extends outside the phospholipid bilayer of the membrane. Here we have compared the substrate and active site-directed inhibitor binding properties of several recombinant constructs of human BACE. The constructs studied here address the importance of catalytic domain glycosylation state, inclusion of domains other than the catalytic domain, and incorporation into a membrane bilayer on the interactions of the enzyme active site with peptidic ligands. We find no significant differences in ligand binding properties among these various constructs. These data demonstrate that the nonglycosylated, soluble catalytic domain of BACE faithfully reflects the ligand binding properties of the full-length mature enzyme in its natural membrane environment. Thus, the use of the nonglycosylated, soluble catalytic domain of BACE is appropriate for studies aimed at understanding the determinants of ligand recognition by the enzyme active site.
Assuntos
Ácido Aspártico Endopeptidases/química , Proteínas Recombinantes/química , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide , Animais , Ácido Aspártico Endopeptidases/metabolismo , Sítios de Ligação , Células CHO , Catálise , Domínio Catalítico , Linhagem Celular , Membrana Celular/metabolismo , Cromatografia Líquida de Alta Pressão , Cricetinae , Relação Dose-Resposta a Droga , Drosophila , Endopeptidases , Escherichia coli/metabolismo , Glicosilação , Humanos , Concentração Inibidora 50 , Cinética , Ligantes , Luz , Bicamadas Lipídicas/metabolismo , Peptídeos/química , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/metabolismo , Espalhamento de Radiação , Fatores de TempoRESUMO
Glycoprotein IIb-IIIa is an abundant platelet receptor of the integrin family that plays a primary role in platelet aggregation. It exists on the platelet surface predominantly in a resting or inactive conformation that is converted to an active binding competent conformation upon platelet activation. There is much interest in studying the difference between active and inactive GP IIb-IIIa, developing therapeutic agents targeted towards GP IIb-IIIa and developing diagnostic assays for antibodies that recognize epitopes on GP IIb-IIIa. We present here the development of a large-scale process for purifying active GP IIb-IIIa from human platelets. The procedure results in 25mg batch sizes of high purity and activity. Additionally, the effects of detergent concentration and impurities such as IgG on ELISA assays are examined.