Synthesis of new quaternized chitosan Schiff bases and their N-alkyl derivatives as antimicrobial and anti-biofilm retardants in membrane technology.

New quaternized salicylidene chitosan Schiff bases (QSCSBs) and their N-octyl derivatives (OQCs) have been synthesized and characterized, aiming to develop innovative antimicrobial and anti-biofilm agents. This research holds immense potential, as these compounds could be utilized as anti-biofouling additives in membrane technology in the future. The synthesis involved the modification of low molecular-weight-chitosan (LMC) through simultaneous Schiff base formation and quaternization processes to create QSCSBs. Subsequently, QSCSBs were catalytically reduced to form quaternized N-benzyl chitosan (QBCs) intermediates, which then underwent nucleophilic substitution reactions affording N-octyl quaternized chitosans (OQCs). Characterization techniques such as elemental, spectral, and microscopic analyses were used to confirm the successful synthesis of these materials. As membrane technology relies on surface charge, QSCSBs and OQCs with large zeta potentials could be used as positively charged additives. Moreover, SEM image revealed the regular distribution of pores and voids across the additives' surfaces raises intriguing questions about their implications for membrane performance. Meanwhile, the superior antibacterial and antibiofilm potential of these materials, particularly QSCSB2 and OQC2, indicate that the utilization of these compounds as anti-biofouling additives in membrane technology could significantly improve the performance and longevity of membranes used in various applications such as water treatment and desalination.

Do women with recurrent miscarriage constitute a high-risk obstetric population?

The aim of this study was to examine if women with history of recurrent miscarriage have a higher risk of maternal and foetal complications in future pregnancies. This was a retrospective case control study that analysed data collected prospectively between 2001 and 2007 from 400 women with history of recurrent miscarriage who achieved pregnancies progressing beyond 24 weeks gestation compared to 39,860 deliveries from the general obstetric database within the same time period. Results showed that women with recurrent miscarriage had significantly increased odds of low Apgar scores at one (odds ratios (OR) 1.57, 95% CI 1.20-2.05) and five minutes (OR 2.0, 95% CI 1.23-3.27), small for gestational age (OR 1.96, 95% CI 1.12-3.43), preterm delivery (OR 1.64, 95% CI 1.22-2.19) and antepartum haemorrhage (OR 7.67, 95% CI 4.23-13.91). The risks were increased in the presence of a male foetus but no difference was observed between primary and secondary miscarriage patients. In conclusion, women with recurrent miscarriage have an increased risk of several maternal and foetal complications and therefore may require closer monitoring during the antenatal period particularly when pregnant with a male foetus.