RESUMO
Multifunctional surface-active polymeric composites are attractive materials for the adsorption of various small molecules. Herein, dual-functionalized micron-sized surface-active composite polymer particles were prepared by a three-step process for CO2 adsorption. First, polystyrene (PS) seed particles were prepared via the dispersion polymerization of styrene. PS/P(MMA-AAm-EGDMA) composite polymer particles were then synthesized by aqueous seeded copolymerization of methyl methacrylate (MMA) and acrylamide (AAm) in the presence of an ethylene glycol dimethacrylate (EGDMA) cross-linker. Finally, the amide moieties of PS/P(MMA-AAm-EGDMA) composite particles were converted into an amine-functionalized composite by using the Hofmann degradation reaction. The presence of primary amine groups on the surface of aminated composite particles was confirmed by some conventional chemical routes, such as diazotization and Schiff's base formation reactions. The formation and functionality of the PS seed, PS/P(MMA-AAm-EGDMA), and aminated PS/P(MMA-AAm-EGDMA) composite polymer particles were confirmed by Fourier transform infrared (FTIR) spectra analyses. Scanning electron microscopy (SEM) analysis revealed spherical shape, size, and surface morphologies of the PS seed, reference composite, and aminated composites. The elemental surface compositions, surface porosity, pore volume, pore diameter, and surface area of both composite particles were evaluated by energy-dispersive X-ray (EDX) mapping, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) analyses. Dynamic light scattering (DLS) and ζ-potential measurements confirmed the pH-dependent surface properties of the functionalized particles. The amount of the adsorbed anionic emulsifier, sodium dodecyl sulfate (SDS), on the surface of aminated PS/P(MMA-AAm-EGDMA) is higher at pH 4 than that at pH 10. A vice versa result was found in the case of cationic surfactant, hexadecyltrimethylammonium bromide (HTABr), adsorption. Synthesized aminated composite particles were used as an adsorbent for CO2 adsorption via bubbling CO2 in an aqueous medium. The changes in dispersion pH were monitored continuously during the adsorption of CO2 under various conditions. The amount of CO2 adsorption by aminated composite particles was found to be 209 mg/g, which is almost double that of reference composite particles.
RESUMO
Nosocomial infection is a major challenge for the appropriate management of burns. The present study aimed to investigate incidence, risk factors, and causative organisms of nosocomial infection in burn patients of Khulna, Bangladesh. This cross-sectional study was conducted among patients admitted to the Burn and Plastic Surgery Department of Khulna Medical College Hospital (KMCH) from January to December 2020. Relevant data were collected from the patients' hospital records. Samples of wound swabs and blood were collected and cultured in the microbiology laboratory of KMCH. Logistic regression models were used to determine risk factors for infective complications in burn patients. All statistical analyses were carried out using SPSS version 26.0. A total of 100 burn patients were included. Mean age was 29.2 years with a male-female ratio of 1.3:1. Flame burns were most prevalent among the patients (41%), followed by scald (23%) and electric burns (15%). Almost 40% patients had full thickness burn. The incidence of nosocomial infection was 42% (wound infection 33% and septicemia 9%). Total body surface area of burn >40% (OR 7.56, 95% CI 2.89-19.81), full thickness burn (OR 34.40, 95% CI 3.25-97.14) and prolonged hospital stay (aOR 1.31, 95% CI 1.15-1.51) were significant risk factors for nosocomial infection. Staphylococcus aureus was the most commonly isolated organism (45%), followed by Streptococcus (24%), Pseudomonas aeruginosa (19%) and Escherichia coli (12%). As the epidemiology of nosocomial infection is not the same in different health facilities, a facility-based comprehensive burn management protocol considering the local epidemiology and causative organisms of burn wound infection is crucial for the prevention and management of nosocomial infections in burn patients.
Les infections nosocomiales sont une préoccupation majeure du traitement bien conduit des brûlés. Cette étude a eu pour but d'évaluer l'incidence, les facteurs de risque de survenue et les bactéries isolées d'infections nosocomiales survenues dans le CTB de Kulna (Bangladesh). Elle a étudié les dossiers l'ensemble des 100 patients admis dans le CTB du CHU de Kulna en 2020. Les analyses bactériologiques ont été réalisées dans le laboratoire du CHU. Une régression logistique a été utilisée pour déterminer les facteurs de risque d'infection. Toutes les analyses statistiques ont été réalisées avec SSPS 26.0. L'âge moyen était de 29,2 ans, le sex-ratio de 1,3H/1F. Les flammes représentaient 41% des causes, les liquides 23% et l'électricité 15%. Quasiment 40% des patients avaient des brûlures profondes. L'incidence des accidents infectieux était de 42% (cutanée 33%, bactériémies 9%). Les facteurs de risque indépendants de survenue d'une infection étaient une atteinte sur >40 % SCT (OR 7,56; IC95 2,89-19,81), une brûlure profonde (OR 34,40 ; IC95 3,25-97,14) et un séjour prolongé (OR 1,31; IC95 1,15-1,51). Les quatre bactéries les plus fréquentes étaient S. aureus (45%), Streptococcus spp (24%), P. æruginosa (19%), et E. coli (12%). Les épidémiologies bactériennes variant selon les services d'où elles sont issues, c'est sur l'épidémiologie locale que doivent se centre les mesures de contrôle des infections nosocomiales.
