Selective, rapid extraction of uranium from aqueous solution by porous chitosan–phosphorylated chitosan–amidoxime macroporous resin composite and differential charge calculation

Article

作者: Zhang, Lieyu ; Zhang, Xiaodie ; Xiong, Ying ; Wang, Qingliang ; Xin, Qi ; Wang, Hongqiang

Herein, a new porous chitosan-phosphorylated chitosan-amidoxime macroporous resin composite (PCAR) was designed and synthesized for the rapid and selective extraction of uranium resources from aqueous solution. This study showed that PCAR exhibited excellent adsorption toward uranium in a pH range of 5-9. The dynamic adsorption process aligned with the quasi-second-order kinetic model and corresponded to the chemical adsorption process. The maximum adsorption capacity was 561.28 mg·g^-1 at pH 6 and 308 K. Mechanism analysis showed that the synergistic effect of the amidoxime group (-(NH₂)C=N-OH), PO, and -NH₂ on the PCAR surface improved the uranium adsorption performance. The differential charge density indicated that the amidoxime and phosphate groups provide lone-pair electrons for the adsorption of UO₂²⁺ and their synergistic effect improves the UO₂²⁺ adsorption performance of PCAR. The uranium distribution coefficients of PCAR and CAR are 4.6 and 2.4 times those of vanadium, respectively. These results indicate that phosphorylation can ameliorate the disadvantage of competitive vanadium adsorption of the amidoxime adsorbent. In addition, PCAR exhibits good reusability and stable adsorption capacity after five adsorption-desorption cycles. Hence, PCAR has excellent potential for uranium extraction from aqueous solution.

2015-05-01·Carbohydrate Polymers1区 · 化学

Polyelectrolyte nanocomplex formation of heparin-photosensitizer conjugate with polymeric scavenger for photodynamic therapy

1区 · 化学

Article

作者: Kim, Sungwon ; Cho, Hana ; Kang, Han Chang ; Huh, Kang Moo ; Li, Li

A polyelectrolyte nanocomplex was prepared via the ionic interaction between the anionic heparin-pheophorbide a (HPhA) conjugate, which served as a water-soluble polysaccharide photosensitizer (PS), and the cationic polyethylenimine (PEI)-β-carotene (PCAR) conjugate, which served as a polymeric scavenger. This nanocomplex was designed to improve the water solubility and tumor specificity of PhA and to only release singlet oxygen at the tumor cell. A stable 150 nm-sized nanocomplex could be formed in the weight ratio range (PCAR/HPhA) of 0.3-0.5 in an aqueous environment. The PCAR scavenger significantly diminished the generation of active singlet oxygen from HPhA in a buffer solution. Singlet oxygen scavenging activity was lost only when HPhA and PCAR were separated from each other due to the dissociation of the complex nanostructures. It was confirmed that HPhA itself has neither colloidal properties nor a decrease in its ability to produce singlet oxygen. At the same time, the HPhA/PEI complex produced singlet oxygen in response to light. In a cell culture system, the cytotoxicity of the HPhA/PCAR nanocomplex toward cancer cells was greatly enhanced due to the efficient generation of singlet oxygen under light irradiation; this finding implies that the scavenging activity of PCAR can be restricted to intracellular environments. These results suggest that the HPhA/PCAR nanocomplex could provide a new activatable PS platform that facilitates more accurate and reliable photodynamic therapy (PDT) with site-specific and controllable production of singlet oxygen to be used for the treatment of cancer.

1999-05-01·Journal of Endourology3区 · 医学

Transrectal Ultrasound Parameters: Presumed Circle Area Ratio and Transitional Zone Area in the Evaluation of Patients with Lower Urinary Tract Symptoms

3区 · 医学

Article

作者: Desai, M M

BACKGROUND AND OBJECTIVESBenign prostatic hyperplasia (BPH) is not the only cause of lower urinary tract symptoms (LUTS) in elderly men. Thus, routine use of invasive measures to debulk the prostate will produce suboptimal treatment outcomes in many patients. We attempted to determine whether two parameters based on transrectal ultrasonography could accurately determine the presence of obstruction and predict the response to therapy.PATIENTS AND METHODSIn the first part of the study, the presumed circle area ratio (PCAR) and transitional zone area ratio (TZAR) were determined in 86 men aged 50 years or greater and correlated with the patient's age, International Prostate Symptom Score (IPSS), and peak flow rate Qmax. The ability of cut-off values of PCAR = 0.75 and TZAR = 0.5 to stratify patients for the presence of obstruction was determined. In the second part of the study, PCAR and TZAR were determined in 25 men in urinary retention, who were further classified as having high voiding pressure (Group A) or an underactive detrusor muscle (Group B). Obstruction was reassessed immediately and 1 month after transurethral resection (TURP), and the ability of PCAR and TZAR to predict treatment outcome was assessed.RESULTSBoth PCAR and TZAR showed weak correlations with IPSS and a moderate inverse correlation with Qmax. The cut-off values were able to separate patients according to Qmax and overall obstructive states. A PCAR of > or = 0.75 or a TZAR of > or = 0.5 would have predicted obstruction in 34 of 36 obstructed patients, and lower values would have correctly predicted the absence of obstruction in 33 of 37 patients. In patients with high voiding pressure, all those with PCAR and TZAR values above the cut-off showed good to average improvement after TURP. In patients with an underactive detrusor, both PCAR and TZAR were extremely useful in predicting the response to TURP.CONCLUSIONIn view of the morbidity and mortality of invasive treatments for BPH, subjecting patients with LUTS to these treatments in the absence of obstruction is irrational. We recommend the use of transrectal ultrasonography measures in the routine evaluation of BPH and reserve the more invasive urodynamic studies for patients with discrepant findings. Further studies in a larger group of patients are needed.

100 项与 aVb6 pCAR(Leucid Bio) 相关的药物交易

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