A novel layer-by-layer heterogeneous cation exchange membrane for heavy metal ions removal from water

A novel layer-by-layer (LbL) cation exchange membrane was prepared for heavy metal ions removal from water via electrodialysis. LBL membranes fabricated by coating of [chitosan-co-activated carbon nanoparticles] layer on polyvinyl chloride-based heterogeneous cation exchange membrane. Betterment in adherence of layers was achieved through glutaraldehyde cross linking. FTIR, FESEM, 3D-surface images and BET analysis were used for LBL membrane characterization. Membrane surface hydrophilicity, flux, membrane potential, transport number, and their permselectivity were studied. FTIR spectra confirm LbL formation decisively. FESEM images and BET analysis demonstrated that coating of second layer on PVC membrane led to a compact structure. LbL membrane showed smoother and more hydrophilic surface compared to pristine membrane. The transport number and permselectivity increased by deposition of second layer whereas sodium flux showed up-down trend. ED experiment showed good ability in heavy metal ions removal for LBL membrane that follows (Cu²⁺> Ni²⁺> Pb²⁺) sequence. EDX analysis showed a competitive adsorption for heavy metal ions on LBL membrane as (Pb²⁺> Cu²⁺≥Ni²⁺). The effect of ultrasonic waves on regeneration of fouled membranes by heavy metals was investigated. The results showed improved performance for the regenerated membrane. Mechanical resistance also improved by utilizing of ACNs in chitosan layer.

Retinal Fibrovascular Proliferation associated with Nocardia Subretinal Abscess

PURPOSE

To report the development of extensive fibrovascular proliferation in association with Nocardia subretinal abscess.

METHOD

Case report.

RESULTS

Extensive retinal neovascularization with tractional retinal detachment developed soon after ocular involvement in a 61-year-old patient with systemic nocardiosis. Fundus fluorescein angiography showed extensive area of capillary nonperfusion and severe leakage from the neovascular complex. The Nocardia subretinal abscess responded to systemic antibiotics, and the retinal neovascularization and tractional retinal detachment stabilized after 3 months.

CONCLUSIONS

Retinal ischemia and severe retinal neovascularization may complicate intraocular nocardiosis. The authors propose secondary retinal vasculitis as a contributing factor towards the development of retinal ischemia in this setting.

Identification of factors contributing to successful self-directed weight loss: a qualitative study

BACKGROUND

Despite the number of weight management programmes and their wide promotion, most overweight and obese individuals tend to lose weight on their own. The present study aimed to understand the characteristics and strategies of those who successfully engage in self-directed weight loss, which could empower other overweight and obese individuals with information and strategies to manage their weight on their own.

METHODS

Men and women who had lost at least 5% of their body weight without direct interaction with professionals or weight management programmes were recruited. Demographic data were collected by questionnaire and participants' weight-loss experiences were explored using semi- structured interviews to elicit in-depth individual experiences and perspectives. Iterative thematic method data analysis was used to generate themes describing contributing factors to the success of self-directed weight loss identified by participants.

RESULTS

Most characteristics of those who successfully self-managed their weight loss were in line with those reported by successful weight losers participating in professional-led projects. However, strategies such as early embedding of new lifestyle behaviours into daily routine, the ability to learn from previous weight-loss experiences, and not requiring social support were identified as distinctive factors that contributed to the success of self-directed weight loss by participants of the present study.

CONCLUSIONS

Overweight or obese individuals with strong internal motivation, problem-solving skills and self-reliance are more likely to be successful at achieving self-directed weight loss. The patients identified with these characteristics could be encouraged to self-manage their weight-loss process, leaving the places available in more resource-intensive professional-led programmes to those individuals unlikely to succeed on their own.