RESUMEN
In this work, we reported the synthesis, characterization and adsorption study of two ß-cyclodextrin (ßCD) cross-linked polymers using aromatic linker 2,4-toluene diisocyanate (2,4-TDI) and aliphatic linker 1,6-hexamethylene diisocyanate (1,6-HDI) to form insoluble ßCD-TDI and ßCD-HDI. The adsorption of 2,4-dinitrophenol (DNP) on both polymers as an adsorbent was studied in batch adsorption experiments. Both polymers were well characterized using various tools that include Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller analysis and scanning electron microscopy, and the results obtained were compared with the native ßCD. The adsorption isotherm of 2,4-DNP onto polymers was studied. It showed that the Freundlich isotherm is a better fit for ßCD-TDI, while the Langmuir isotherm is a better fit for ßCD-HMDI. The pseudo-second-order kinetic model represented the adsorption process for both of the polymers. The thermodynamic study showed that ßCD-TDI polymer was more favourable towards 2,4-DNP when compared with ßCD-HDI polymer. Under optimized conditions, both ßCD polymers were successfully applied on various environmental water samples for the removal of 2,4-DNP. ßCD-TDI polymer showed enhanced sorption capacity and higher removal efficiency (greater than 80%) than ßCD-HDI (greater than 70%) towards 2,4-DNP. The mechanism involved was discussed, and the effects of cross-linkers on ßCD open up new perspectives for the removal of toxic contaminants from a body of water.
RESUMEN
BACKGROUND: Little is known of the course and prognosis of hypersensitivity vasculitis (HV). METHODS: Sixty-one cases of idiopathic HV were biopsied and followed-up for 5 years. RESULTS: There were two predominant patterns of presentation: palpable purpura (PP) and vasculitic ulcers (VU). The former was self-limiting, whereas the prognosis of the latter was poor. Findings on histopathology correlate well in PP patients having acute episodes, whereas in patients with VU there is correlation with duration and recurrence. CONCLUSION: A biopsy of a fresh lesion is recommended to help in determining the outcome.
Asunto(s)
Vasculitis Leucocitoclástica Cutánea/patología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Púrpura/patología , Úlcera Cutánea/patologíaRESUMEN
The content of survival factors for sympathetic, sensory and parasympathetic neurones in the heart was examined after denervation with either 6-hydroxydopamine or vagal transection. There was a correlation between the type of nerve sectioned in vivo and the type of neurone whose survival in vitro was enhanced by the presence of denervated target tissue.