Enhancement in photocatalytic selectivity of TiO2-based nano-catalyst through molecular imprinting technology.

Improvement in the photocatalytic selectivity is imperative for the effective and efficient utilization of catalysts. In this study, a molecularly imprinted polymer-coated iron-doped titanium dioxide (Fe-TiO2@MIP) nanocomposite was successfully synthesized by precipitation polymerization while using RB-19 as a template. The synthesized nanocomposites (Fe-TiO2@MIP and Fe-TiO2@NIP) were characterized by Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-EMMETT-Teller (BET), and UV-visible spectrophotometry. The optimized binding experiments revealed a high imprinting factor of 5.0 for RB-19. The catalytic degradation efficiency and selectivity of Fe-TiO2@MIP enhanced to almost complete degradation of RB-19 from 70% for the parent Fe-TiO2 and 76% for Fe-TiO2@NIP. An outstanding degradation selectivity of RB-19 was achieved compared to other competitive dyes. Finally, the analysis of the non-degraded and degraded RB-19 by ESI-MS revealed the presence of different intermediates that fits well with the proposed degradation mechanism. The study opens new possibilities of selective photo-degradation of targeted contaminants that may ultimately lead to efficient use of photocatalysts.

New series of 3,5-disubstituted tetrahydro-2H-1,3,5-thiadiazine thione (THTT) derivatives: Synthesis and potent antileishmanial activity.

Four series of heterocyclic compounds, namely, tetrahydro-2H-1,3,5-thiadiazine thione derivatives were synthesized in good to excellent yields and were screened for their in vitro antileishmanial activities against Leishmania major (promastigotes). Most of the compounds showed significant antileishmanial activity within the range of IC50 = 15.48-39.36 µM when compared with standard pentamidine (IC50 = 14.95 µM). The structure-activity relationship showed that N-3 and N-5 substituents have a key role against leishmanicidal activity. The ester analogues (series B) were found to have a 1.5 to 5-fold reduced activity compared to their acidic counterparts. Cytotoxicity against mammalian mouse fibroblast 3 T3 cells was also evaluated and compared between the acid and its ester analogue. The reduction of antileishmanial activity and loss of toxicity in the newly developed THTT ester derivative indicates that these compounds can be used as a template study for the production of effective antileishmanial ester prodrugs.

Determinants of lower extremity amputations: an institutional experience.

OBJECTIVE: To determine the determinants of lower extremity amputations in diabetics and non-diabetics in a tertiary care institute. STUDY DESIGN: Cross-sectional, analytical study. PLACE AND DURATION OF STUDY: Outpatients Department of the Institute of Physical Medicine and Rehabilitation, Dow University of Health Sciences, Karachi, from January 2007 to December 2010. METHODOLOGY: All patients with amputations reporting at the study centre for prosthesis fitting were included in the study. Patient`s age, level of amputation, stump complications and associated risk factors of amputation were recorded on a structured proforma. Prosthesis and orthotic assessment were carried out. The frequency and determinants were collected to compare diabetic and non-diabetic amputees. The data was analyzed in SPSS windows version 16. RESULTS: A total of 1091 subjects were provided prosthesis, including 847 males (77.6%). Mean age in diabetic and nondiabetics being 49.6 ± 15.2 and 26.6 ± 17.9 years respectively which is significant at (p < 0.001). Socioeconomic status and educational levels were significantly associated with diabetic status (p < 0.001). Amputation was more common in non-diabetic 858 (78.6%) compared to diabetics 233 (21.4%). CONCLUSION: This study has identified that most common and significant predictors were gender, low social status and educational levels. Other significant predictors of amputation identified were type of lesion, (infections and ischaemia), initial diagnosis acute/chronic arterial insufficiency and diabetic foot.