Exploring antimicrobial and biocompatible applications of eco-friendly fluorescent carbon dots derived from fast-food packaging waste transformation.

In the face of escalating environmental concerns, particularly the pervasive issue of non-biodegradable fast-food packaging waste, this study introduces a ground-breaking solution that not only addresses waste management but also advances biomedical technology. Utilizing the underexploited resource of Fucoidan, a sulfated polysaccharide from brown algae, we have innovatively transformed fast-food packaging waste into eco-friendly fluorescent carbon dots (FPCDs). These FPCDs were meticulously characterized through advanced techniques like FT-IR, TEM, and XRD, shedding light on their unique structure, morphology, and composition. A significant discovery of this study is the potent antimicrobial properties of these FPCDs, which demonstrate remarkable effectiveness against specific bacterial and fungal strains. This opens new avenues in the realm of biomedical applications, including imaging, drug delivery, and biosensing. Furthermore, extensive toxicity assessments, including the Brine shrimp lethality assay and Adult Artemia toxicity tests, underscore the safety of these nanoparticles, bolstering their applicability in sensitive medical scenarios. Our research presents a compelling dual approach, ingeniously tackling environmental sustainability issues by repurposing waste while simultaneously creating valuable materials for biomedical use. This dual benefit underscores the transformative potential of our approach, setting a precedent in both waste management and medical innovation.

Commissioning of a PTW 34070 large-area plane-parallel ionization chamber for small field megavoltage photon dosimetry.

PURPOSE: This study investigates a large-area plane-parallel ionization chamber (LAC) for measurements of dose-area product in water (DAPw ) in megavoltage (MV) photon fields. METHODS: Uniformity of electrode separation of the LAC (PTW34070 Bragg Peak Chamber, sensitive volume diameter: 8.16 cm) was measured using high-resolution microCT. Signal dependence on angle α of beam incidence for square 6 MV fields of side length s = 20 cm and 1 cm was measured in air. Polarity and recombination effects were characterized in 6, 10, and 18 MV photons fields. To assess the lateral setup tolerance, scanned LAC profiles of a 1 × 1 cm2 field were acquired. A 6 MV calibration coefficient, ND,w,LAC , was determined in a field collimated by a 5 cm diameter stereotactic cone with known DAPw . Additional calibrations in 10 × 10 cm2 fields at 6, 10, and 18 MV were performed. RESULTS: Electrode separation is uniform and agrees with specifications. Volume-averaging leads to a signal increase proportional to ~1/cos(α) in small fields. Correction factors for polarity and recombination range between 0.9986 to 0.9996 and 1.0007 to 1.0024, respectively. Off-axis displacement by up to 0.5 cm did not change the measured signal in a 1 × 1 cm2 field. ND,w,LAC was 163.7 mGy cm-2 nC-1 and differs by +3.0% from the coefficient derived in the 10 × 10 cm2 6 MV field. Response in 10 and 18 MV fields increased by 1.0% and 2.7% compared to 6 MV. CONCLUSIONS: The LAC requires only small correction factors for DAPw measurements and shows little energy dependence. Lateral setup errors of 0.5 cm are tolerated in 1 × 1 cm2 fields, but beam incidence must be kept as close to normal as possible. Calibration in 10 × 10 fields is not recommended because of the LAC's over-response. The accuracy of relative point-dose measurements in the field's periphery is an important limiting factor for the accuracy of DAPw measurements.

Antiplasmodial activity of two marine polyherbal preparations from Chaetomorpha antennina and Aegiceras corniculatum against Plasmodium falciparum.

The ocean covers more than 70% of earth surface and hosts most 300,000 described species of plants and animals to use, which have been virtually unexploited for the development of medicines. Marine plants are the good source of biologically active entities which exhibit therapeutic properties, when applied single or in combination of different plant extracts (polyherbal). Polyherbal preparations are always a complex mixture of different forms and thus different compounds, which might act as agonistic, synergistic, complementary, antagonistic or toxic way. The present study was initially carried out to test the antiplasmodial activity of 13 mangrove plants and eight seaweeds species distributed along the coast of south India. Of these, mangrove species Aegiceras corniculatum and the seaweed species Chaetomorpha antennina have shown maximum antiplasmodial activity. Hence, the present study was mooted out to increase the percentage of antiplasmodial activity when applied as polyherbal preparations. The effect of marine polyherbal preparations from the methanolic extracts of two marine plants A. corniculatum and C. antennina for their antiplasmodial activity was tested. It shows that the polyherbal extract showed 63.50 ± 0.408% suppression of parasitaemia against Plasmodium falciparum at 1.5 mg ml⁻¹ concentration. In vivo test was carried out with rat animal model to find out the effectiveness of the polyherbal extracts in the live system, which reveals that polyherbal extracts have exhibited remarkable antiplasmodial activity (50.57 ± 0.465%) against Plasmodium berghei at 120 mg kg⁻¹ bw. This study shows that combinations of mangrove plants and seaweeds extracts had a source of lead compounds for the development of new drugs for the treatment of malaria.

Maintaining the accuracy of the (60)Co calibration service at the ARPANSA post source replacement in 2010.

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) maintains a (60)Co teletherapy source primarily for the calibration of therapy dosemeters. The source and encapsulating head were replaced in early 2010 with an Eldorado 78 head and new (60)Co source. In this article we present the results of ongoing accuracy and stability measurements since the replacement. A number of formal and informal indirect comparisons have been carried out with laboratories holding primary and secondary standards for (60)Co. ARPANSA chambers have also been calibrated at international primary standard laboratories allowing comparison of calibration coefficients and thus (60)Co absorbed dose standards. (60)Co calibration coefficients supplied by manufacturers of chambers were compared to those measured at the ARPANSA when this calibration was traceable to a primary standard. ARPANSA also participates in an annual international mailed dosimetry audit conducted by the International Atomic Energy Agency. The results thus far demonstrate that the absorbed doses to water delivered by the new ARPANSA (60)Co source are consistent with international doses within the stated uncertainties.

Direct calibration in megavoltage photon beams using Monte Carlo conversion factor: validation and clinical implications.

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) has established a method for ionisation chamber calibrations using megavoltage photon reference beams. The new method will reduce the calibration uncertainty compared to a (60)Co calibration combined with the TRS-398 energy correction factor. The calibration method employs a graphite calorimeter and a Monte Carlo (MC) conversion factor to convert the absolute dose to graphite to absorbed dose to water. EGSnrc is used to model the linac head and doses in the calorimeter and water phantom. The linac model is validated by comparing measured and modelled PDDs and profiles. The relative standard uncertainties in the calibration factors at the ARPANSA beam qualities were found to be 0.47% at 6 MV, 0.51% at 10 MV and 0.46% for the 18 MV beam. A comparison with the Bureau International des Poids et Mesures (BIPM) as part of the key comparison BIPM.RI(I)-K6 gave results of 0.9965(55), 0.9924(60) and 0.9932(59) for the 6, 10 and 18 MV beams, respectively, with all beams within 1σ of the participant average. The measured kQ values for an NE2571 Farmer chamber were found to be lower than those in TRS-398 but are consistent with published measured and modelled values. Users can expect a shift in the calibration factor at user energies of an NE2571 chamber between 0.4-1.1% across the range of calibration energies compared to the current calibration method.