Purification of Aqueous Media by Biochars: Feedstock Type Effect on Silver Nanoparticles Removal.

Due to the harmful effects of nanoparticles in the environment, their effective removal from aqueous media is of great importance. This paper described the research on the silver nanoparticles (Ag-NPs) sorption on biochars obtained from different feedstock types. The sorbents were produced through pyrolysis (double-barrel method) of the vineyard (BV), paulownia tree (BP), and tobacco (BT). BV exhibited the highest specific surface area, porosity, value of variable surface charge, and content of surface acidic functional groups among the used biochars. The pseudo-second order model best described the obtained adsorption kinetics, whereas the Freundlich model accounted for the registered adsorption data. The Ag-NPs removal was highly efficient in the case of BV, especially in the nanoparticle concentration range 50-500 mg/L. Thus, this biochar can be considered as an ecofriendly, effective, low-cost organic adsorbent, potentially used in the aqueous media purification.

Higher 25-Hydroxyvitamin D Levels Are Associated With Lower Proteinuria in Kidney Transplant Recipients.

OBJECTIVES: Proteinuria is associated with decreased graft and patient survival after kidney transplantation. Increasing evidence shows that vitamin D has antiproteinuric and renoprotective effects. The aim of our study was to assess the influence of 25-hydroxyvitamin D levels on proteinuria after kidney transplantation. MATERIAL AND METHODS: Between May 1, 2012, and November 30, 2012, we tested 395 kidney transplant recipients for 25-hydroxyvitamin D levels during their regular visits to our transplant center together with routine blood sampling and proteinuria testing. Patients within 12 months of transplant, who had undergone parathyroidectomy, had unstable graft function, had concomitant intake of calcineurin inhibitors and mammalian target of rapamycin inhibitors were not included in the study. Subjects with advanced liver disease, or receiving vitamin D supplementation were also excluded. All laboratory, clinical, and therapeutic factors for proteinuria were taken into consideration. Statistical analyses included descriptive statistics and univariate and multivariate log-log regression with backward selection (SPSS version 22.0; SPSS Inc., Chicago, IL, USA), with significance at P < .05. Determination of total 25-hydroxyvitamin D levels was performed by a validated liquid chromatography-tandem mass spectrometry method. RESULTS: Our study group included 230 patients (148 men, 82 women). Positive association was established between proteinuria and history of diabetes mellitus, rejection episode 12 months within testing for 25-hydroxyvitamin D levels, and use of mammalian target of rapamycin inhibitors (P < .05). Significant negative relations were detected for patient age, graft function, and 25-hydroxyvitamin D concentrations (P < .05). CONCLUSIONS: Our study established that better vitamin D status is associated with lower proteinuria. However, further research is needed to clarify the possible renoprotective properties of vitamin D.

Relationship between vitamin D status and immunosuppressive therapy in kidney transplant recipients.

There is a growing body of evidence for the protective role of vitamin D in diabetes mellitus (DM), infection, cancer, cardiovascular disease, immune disorders and kidney function. Considering the reported high prevalence of vitamin D insufficiency among kidney transplant recipients (KTRs), the aim of this study was to assess the influence of immunosuppressive therapy and other factors on vitamin D status in such patients. The study included 289 KTRs (189 males and 100 females) who consented to participate. The first test for 25-hydrohyvitamin D [25(OH)D] was performed by a validated liquid chromatography-tandem mass spectrometry method. Influence of immunosuppressive drugs and previously reported predictors on vitamin D status was assessed by descriptive statistics, univariate and multivariate regression. Our results showed that only 53 patients (18.34%) of the studied KTRs were vitamin D sufficient. In addition to a well expected positive association between serum 25(OH)D and summer blood sampling (p < 0.05) and inverse relationship between vitamin D status and DM, gender (female) and body mass index, serum 25(OH)D was found to be inversely associated with calcineurin inhibitors (CNI) (p < 0.05) and unaffected by other immunosuppressive agents. Our study demonstrated high prevalence of vitamin D insufficiency after kidney transplantation in the studied cohort of patients. Apart from female gender, winter months, DM and overweight, the use of CNI could be considered an additional significant predictor of lower 25(OH)D in Bulgarian KTRs.