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Herein, the ability of gamma irradiation to enhance the photoluminescence properties of graphene quantum dots (GQDs) was investigated. Different doses of γ-irradiation were used on GQDs to examine the way in which their structure and optical properties can be affected. The photoluminescence quantum yield was increased six times for the GQDs irradiated with high doses compared to the nonirradiated material. Both photoluminescence lifetime and values of optical band gap were increased with the dose of applied gamma irradiation. In addition, the exploitation of the gamma-irradiated GQDs as photosensitizers was examined by monitoring the production of singlet oxygen under UV illumination. The main outcome was that the GQDs irradiated at lower doses act as better photoproducers than the ones irradiated at higher doses. These results corroborate that the structural changes caused by gamma irradiation have a direct impact on GQD ability to produce singlet oxygen and their photostability under prolonged UV illumination. This makes low-dose irradiated GQDs promising candidates for photodynamic therapy.

Background: Acquisition of Hospital-acquired infections (HAIs) in intensive care units (ICUs) predispose patients to higher mortality rates and additional adverse events. Serbian adult ICUs are rarely investigated for HAIs. The aim of this study was to look into HAIs in an adult ICU and identify risk factors for acquisition of HAIs and mortality. Methods: This retrospective study included 355 patients hospitalized over a 2-year period. Patient characteristics, antimicrobial resistance patterns, and risk factors of acquisition and predictors of mortality in patients who had a HAI were examined. Results: HAIs were diagnosed in 32.7% of patients. Resistance rates > 50% were observed in all antimicrobials except for tigecycline (14%), colistin (9%), and linezolid (0%). Predictors of HAI acquisition were underlying viral CNS infections and invasive devices-urinary and central venous catheters, and nasogastric tubes. Diabetes mellitus and intubation (odds ratio 2.5 and 6.7, P = .042 and <.001) were identified as predictors for increased mortality in patients who had a HAI. Conclusions: Prevalence of HAIs and resistance rates are high compared to ICUs in other European countries. Risk factors for both acquisition of HAI and mortality were identified. Large-scale studies are necessary to look at HAIs in adult ICUs in Serbia.

Antibacterial potentials of four graphene based nanomaterials are tested on a wide range of bacteria.

A comprehensive overview of selected synthetic methods for graphene and graphene based nanomaterials production with the emphasis on the reaction conditions, the quality of obtained graphene nanomaterials and a variety of potential applications.

Presented results indicate that in the selected medium, gamma irradiation at low doses induces the lowering in the GQDs height due to the lower number of graphene layers in their structure. Unexpectedly, irradiation in the same medium at 200 kGy induce a significant increase in GQDs height and caused observable agglomeration.

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