Removal of trace organic contaminants by melamine-tuned highly cross-linked polyamide TFC membranes.

In recent years, forward osmosis (FO) has represented numerous potential applications in safe water production. In this study, we improved the performance of FO thin film composite (TFC) membranes for the removal of trace organic compounds (TOrCs) by tuning the chemistry of its top active layer. The TFC membranes were synthesized by interfacial polymerization (IP) reaction between amine-containing monomers, e.g., meta-phenylene diamine (MPD) or para-phenylenediamine (PPD), and an acid chloride monomer, e.g., trimesoyl chloride (TMC). Owing to three free amine functionals over main core, melamine was used in the amine monomers solution to increase cross-linking among polyamide chains. Chemical and morphological characterization of the prepared membranes confirmed that melamine was successfully incorporated into the chemical structure of the top PA layer. Two agricultural toxic materials (atrazine and diazinon) were used to investigate the capability of the newly fabricated membranes in the removal of TOrCs. The obtained results showed that melamine-improved FO membranes provided higher atrazine and diazinon rejections in two different FO membrane configurations, including active layer facing feed solution (ALF) and active layer facing draw solution (ALD). The highest rejections of both diazinon (99.4%) and atrazine (97.3%) were achieved when the melamine modified MPD-based membrane served in ALF mode with 2 M NaCl as a draw solution.

Sacral insufficiency fracture, a rare complication of posterior spinal instrumentation.

Sacral insufficiency fracture is a rare complication of the lumbar spinal surgery. It is normally reported as a late complication of the multi-segment spinal fixation in females with osteoporotic bone. We present the case of an elderly gentleman who suffered this complication spontaneously on the second postoperative day. To the best of our knowledge this has never been reported in Pakistan. Sacral alae are directly in line with weight bearingwhile walking and should be kept in mind when mobilizing a postoperative patient whose previous history indicates such risk factors. Once injury is suspected, CT scan is recommended as x-rays may not always reveal the injury. In literature, these fractures have almost always been treated conservatively.1 Conservative management wasnot tolerated well in our case and we proceeded with surgical management using S2 sacral alar iliac screws (S2 AI screws) to extend the previous lumbosacral fusion construct. S2 AI screws are a novel technique used for bone lumbosacral fusion and studies have shown to have lower rate of screw breakage under stress and need for revision surgery with their use.