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International Journal of Biological... Jun 2024A superabsorbent hydrogel was prepared by the free-radical copolymerization of natural rubber (NR) latex with poly(acrylic acid) (PAA) at NR loadings up to 50 wt%. An...
A superabsorbent hydrogel was prepared by the free-radical copolymerization of natural rubber (NR) latex with poly(acrylic acid) (PAA) at NR loadings up to 50 wt%. An NR/PAA hydrogel containing 40 wt% of NR (NR-40) had a water absorption capacity of 214 g/g (21,400 %) of its dry weight. The compressive modulus increased 512 % and sample integrity was improved due to the physical entanglement of NR chains. NR-40 hydrogel removed 97 % of methylene blue (MB) from the aqueous solution in 1 h (at initial concentrations of 10-1000 mg/L) and produced a maximum removal of 1191 mg MB/g of hydrogel at an initial MB concentration of 4500 mg/L. The adsorption of MB was an endothermic process. Fourier transform infrared spectroscopy indicated that hydrogen bonding and electrostatic interaction drove the process. After the in-situ incorporation of ZnO into NR-40, absorbed energy from sunlight generated active species that could photocatalytically degrade adsorbed MB in the hydrogel matrix. The scavenger tests indicated that superoxide radical anions and hydroxyl radicals were the main species for this process. The hydrogel composite material showed good stability and could be regenerated and reused over 10 cycles, degrading >80 % of the adsorbed dye. This novel natural-based hydrogel provides double functions of adsorption and photodegradation of toxic dyes without the requirement of chemicals and a separation process.
PubMed: 38945320
DOI: 10.1016/j.ijbiomac.2024.133421 -
International Journal of Biological... Jun 2024Petroleum-based packaging materials are nondegradable and unsustainable and thus are harmful to the environment. Renewable packaging films prepared from bio-based raw...
Petroleum-based packaging materials are nondegradable and unsustainable and thus are harmful to the environment. Renewable packaging films prepared from bio-based raw materials are promising alternatives to petroleum-based packaging materials. In this study, colorless and transparent bio-based films were successfully cast using a solution containing a mixture of arabinogalactan (AG) and poly (vinyl alcohol) (PVA). Vanillin was incorporated into the mixture to endow the films with UV-shielding, antioxidant, and antibacterial properties. The morphological, physical, antioxidant, and antibacterial properties of the blend films were then characterized. At an AG:PVA weight ratio of 1:3, and the vanillin content was 0.15 %, the tensile strength of the AG/PVA/Vanillin (APV) films reached ~28 MPa, while their elongation at break reached ~475 %. The addition of vanillin significantly affected the antioxidant and antibacterial properties of the blend films, which exhibited superb UV barrier capacity. The APV films exhibited extremely low oxygen transmittance, delaying the onset of mold/rot in strawberries and reducing their weight loss. Because of the heat sealability of the blend films, they can be used for encapsulating various substances, such as concentrated laundry liquid. Moreover, the blend films were recyclable and biodegradable. Thus, these films have great potential for applications that require sustainable packaging.
PubMed: 38945318
DOI: 10.1016/j.ijbiomac.2024.133535 -
Journal of Pharmacological and... Jun 2024First-order compartment models are common tools for modelling many biological processes, including pharmacokinetics. Given the compartments and the transfer rates,...
First-order compartment models are common tools for modelling many biological processes, including pharmacokinetics. Given the compartments and the transfer rates, solutions for the time-dependent quantity (or concentration) curves can normally be described by a sum of exponentials. This paper investigates cases that go beyond simple sums of exponentials. With specific relations between the transfer rate constants, two exponential rate constants can be equal, in which case the normal solution cannot be used. The conditions for this to occur are discussed, and advice is provided on how to circumvent these cases. An example of an analytic solution is given for the rare case where an exact equality is the expected result. Furthermore, for models with at least three compartments, cases exist where the solution to a real-valued model involves complex-valued exponential rate constants. This leads to solutions with an oscillatory element in the solution for the tracer concentration, i.e., there are cases where the solution is not a simple sum of (real-valued) exponentials but also includes sine and cosine functions. Detailed solutions for three-compartment cases are given. As a tentative conclusion of the analysis, oscillatory solutions appear to be tied to cases with a cyclic element in the model itself.
PubMed: 38945309
DOI: 10.1016/j.vascn.2024.107534 -
American Journal of Infection Control Jun 2024The mounted UV-C lamp requires no separate space or labor for transport, but data on its effectiveness for surface disinfection are scarce. We aimed to evaluate the...
BACKGROUND
The mounted UV-C lamp requires no separate space or labor for transport, but data on its effectiveness for surface disinfection are scarce. We aimed to evaluate the performance of ceiling-mounted UV-C lamps.
METHODS
This study was conducted in an empty room with UV-C lamps in the biocontainment unit of a tertiary care hospital in South Korea. UV-C lamps were installed on the ceiling of the patient room, anteroom, and toilet. Each pathogen (Staphylococcus aureus, Escherichia coli, Candida krusei, Bacillus cereus, and Mycobacterium peregrinum) was inoculated on blood agar plates and placed in 20 selected places from the UV-C lamp, and irradiation was applied for 15 min. As a control group, the bacterial solution was diluted 10,000 times and UV was not applied.
RESULTS
A mean ± SD of 5.95 ± 0.91 log reduction was observed with UV irradiation compared with the control. The log reduction was greatest for S. aureus [median, 7.05 (IQR, 6.49-7.26)] and least for M. peregrinum [median, 4.88 (IQR, 4.58-5.24)]. The degree of log reduction was inversely proportional to the square of the distance from the UV-C lamp (R = -0.12, p < 0.001).
CONCLUSIONS
In this study, ceiling-mounted UV-C demonstrated effective disinfection of at least 4-log reduction of the test organisms within a 4-m distance. Mounted UV-C lighting is a considerable option for improving surface disinfection.
PubMed: 38945300
DOI: 10.1016/j.ajic.2024.06.020 -
Clinical Microbiology and Infection :... Jun 2024Herpesviruses represent common and significant infectious complications after allogeneic hematopoietic cell transplantation (HCT). In the last decade, major advances in... (Review)
Review
BACKGROUND
Herpesviruses represent common and significant infectious complications after allogeneic hematopoietic cell transplantation (HCT). In the last decade, major advances in the prevention and treatment of these infections were accomplished.
OBJECTIVES
The aim of this paper is to review the recent advances in the prophylaxis and treatment of herpesvirus infections after allogeneic HCT, to assess the persisting challenges, and to offer future directions for prevention and management of these infections.
SOURCES
We searched PubMed for relevant literature regarding specific herpesviruses complicating allogeneic HCT through March 2024.
CONTENT
The largest advances in this past decade were witnessed for cytomegalovirus (CMV) with the advent of letermovir for primary prophylaxis and the development of maribavir as an option for refractory and/or resistant CMV infections in transplant recipients. For Varicella Zoster Virus, prevention of reactivation with the recombinant zoster vaccine offers an additional prophylactic intervention. Pritelivir is being explored for treatment of drug resistant or refractory Herpes Simplex Virus infections. While rituximab is now an established option for preemptive therapy for Epstein Barr Virus, HHV-6 remains the most elusive virus of the herpesvirus family, with lack of evidence supporting benefit of any agent for prophylaxis or for optimal preemptive therapy.
IMPLICATIONS
While considerable advances have been achieved for the treatment and prevention of herpes virus infections, most notably with CMV, the coming years should hold additional opportunities to tame the beast in these herpesviruses post allogeneic HCT, with the advent of new antivirals, cell-mediated immunity testing, and cytotoxic T lymphocytes infusions.
PubMed: 38945270
DOI: 10.1016/j.cmi.2024.06.020 -
The Science of the Total Environment Jun 2024Ecological succession and restoration rapidly promote multiple dimensions of ecosystem functions and mitigate global climate change. However, the factors governing the...
Ecological succession and restoration rapidly promote multiple dimensions of ecosystem functions and mitigate global climate change. However, the factors governing the limited capacity to sequester soil organic carbon (SOC) in old forests are poorly understood. Ecological theory predicts that plants and microorganisms jointly evolve into a more mutualistic relationship to accelerate detritus decomposition and nutrient regeneration in old than young forests, likely explaining the changes in C sinks across forest succession or rewilding. To test this hypothesis, we conducted a field experiment of root-mycorrhizal exclusion in successional subtropical forests to investigate plant-decomposer interactions and their effects on SOC sequestration. Our results showed that SOC accrual rate at the 0-10 cm soil layer was 1.26 mg g yr in early-successional arbuscular mycorrhizal (AM) forests, which was higher than that in the late-successional ectomycorrhizal (EcM) forests with non-significant change. A transition from early-successional AM to late-successional EcM forests increase fungal diversity, especially EcM fungi. In the late-successional forests, the presence of ectomycorrhizal hyphae promotes SOC decomposition and nutrient cycle by increasing soil nitrogen and phosphorus degrading enzyme activity as well as saprotrophic microbial richness. Across early- to late-successional forests, mycorrhizal priming effects on SOC decomposition explain a slow-down in the capacity of older forests to sequester soil C. Our findings suggest that a transition from AM to EcM forests supporting greater C decomposition can halt the capacity of forests to provide nature-based global climate change solutions.
PubMed: 38945245
DOI: 10.1016/j.scitotenv.2024.174330 -
The Science of the Total Environment Jun 2024Axarquia is a semi-arid region in southern Spain that in the past 25 years has experienced significant population growth, along with an economic boom driven by an...
Axarquia is a semi-arid region in southern Spain that in the past 25 years has experienced significant population growth, along with an economic boom driven by an increasing influx of tourists to Costa del Sol and the expansion of irrigated export-oriented subtropical crops. The combination of these factors has led to a chronic structural scarcity condition that has been intensified by the occurrence of a long and extreme drought. As a result, its only reservoir has reached historically low levels and the piezometric levels in its main aquifer have decreased significantly, suggesting that groundwater reserves are being overexploited. The water crisis is impacting citizens (urban supply), farmers (losses of yields and crops), and the environment (decreasing water reserves). The authorities have responded through supply-side measures such as incorporating reclaimed wastewater in the system and planning the deployment of desalination infrastructure in the region, but demand control and proper governance are required to guarantee sustainability. Consequently, in this case study we apply the European Environment Agency's DPSIR (driving forces, pressures, state, impact, and response model of intervention) framework to understand the basin closure process in Axarquia and assess the main actions that have been undertaken by public and private sector stakeholders to address the challenges faced by the region. Our results provide a valuable reference case to support the analysis of similar closure events, the early identification of potential crisis conditions, and the design of potential solutions in water scarce regions in the European Union, the Mediterranean, and elsewhere.
PubMed: 38945242
DOI: 10.1016/j.scitotenv.2024.174318 -
The Science of the Total Environment Jun 2024Biodegradable plastics play a vital role in addressing global plastics disposal challenges. Poly-3-hydroxybutyrate (P3HB) is a biodegradable bacterial intracellular...
Biodegradable plastics play a vital role in addressing global plastics disposal challenges. Poly-3-hydroxybutyrate (P3HB) is a biodegradable bacterial intracellular storage polymer with substantial usage potential in agriculture. Poly-3-hydroxybutyrate and its degradation products are non-toxic; however, previous studies suggest that P3HB biodegradation negatively affects plant growth because the microorganisms compete with plants for nutrients. One possible solution to this issue could be inoculating soil with a consortium of plant growth-promoting and N-fixing microorganisms. To test this hypothesis, we conducted a pot experiment using lettuce (Lactuca sativa L. var. capitata L.) grown in soil amended with two doses (1 % and 5 % w/w) of P3HB and microbial inoculant (MI). We tested five experimental variations: P3HB 1 %, P3HB 1 % + MI, P3HB 5 %, P3HB 5 % + MI, and MI, to assess the impact of added microorganisms on plant growth and P3HB biodegradation. The efficient P3HB degradation, which was directly dependent on the amount of bioplastics added, was coupled with the preferential utilization of P3HB as a carbon (C) source. Due to the increased demand for nutrients in P3HB-amended soil by microbial degraders, respiration and enzyme activities were enhanced. This indicated an increased mineralisation of C as well as nitrogen (N), sulphur (S), and phosphorus (P). Microbial inoculation introduced specific bacterial taxa that further improved degradation efficiency and nutrient turnover (N, S, and P) in P3HB-amended soil. Notably, soil acidification related to P3HB was not the primary factor affecting plant growth inhibition. However, despite plant growth-promoting rhizobacteria and N-fixing microorganisms originating from MI, plant biomass yield remained limited, suggesting that these microorganisms were not entirely successful in mitigating the growth inhibition caused by P3HB.
PubMed: 38945229
DOI: 10.1016/j.scitotenv.2024.174328 -
Chemosphere Jun 2024Due to its adverse health and environmental impacts, groundwater contamination by toxic organic compounds such as chlorinated solvents is a global concern. The...
Due to its adverse health and environmental impacts, groundwater contamination by toxic organic compounds such as chlorinated solvents is a global concern. The slow-release permanganate gel (SRP-G) is a mixture of potassium permanganate (KMnO) and colloidal silica solution. The SRP-G is designed to radially spread after injection via wells, gelate in situ to form gel barriers containing permanganate (MnO), and slowly release MnO to treat plumes of chlorinated solvents in groundwater. This study aimed to characterize the effects of temperature on the dynamics of SRP-G in saturated porous media. In gelation batch tests, the viscosity of ambient-temperature (24 C) SRP-G with 30 g/L-KMnO was 21 cP at 70 min, 134 cP at 176 min, and peaked at 946 cP to solidification at 229 min. The viscosity of low-temperature (4 C) SRP-G with 30 g/L-KMnO was 71 cP at 273 min, 402 cP at 392 min, and peaked at 818 cP to solidification at 485 min. A similar pattern, e.g., increased gelation lag time with low-temperature SRP-G, was observed for SRP-Gs with 40 g/L, 50 g/L, and 60 g/L KMnO. In flow-through tests using a glass column filled with saturated sands, injection rates, spreading rates, and release durations were 0.6 mL/min, 46 mm/min, and 33 hr for KMnO(aq), 0.2 mL/min, 2 mm/min, and 38 hr for ambient-temperature SRP-G, and 0.4 mL/min, 16 mm/min, and 115 hr for low-temperature SRP-G, respectively. These results indicated that the injectability, injection rate, and gelation lag time of SRP-G and the size, release rate, and release duration of MnO gel barriers can be increased at low temperatures. The low-temperature SRP-G scheme can be useful for treating large or dilute dissolved plumes of chlorinated solvents or other pollutants in groundwater.
PubMed: 38945223
DOI: 10.1016/j.chemosphere.2024.142716 -
Chemosphere Jun 2024Antibiotics such as sulfamethoxazole (SUF), ciprofloxacin (CIP) and erythromycin (ERY) are frequently detected in water systems without being efficiently removed during...
Antibiotics such as sulfamethoxazole (SUF), ciprofloxacin (CIP) and erythromycin (ERY) are frequently detected in water systems without being efficiently removed during water treatment. This study synthesized a graphitic carbon nitride-enhanced vanadium ferrite (VFeO@g-CN) as a photocatalyst for degrading SUF, CIP and ERY in an aqueous solution. VFeO@g-CN was characterized with X-ray diffractometry (XRD), thermogravimetry analysis (TGA), ultraviolet (UV)-visible spectrophotometry, scanning electron microscope (SEM) and transmission electron microscope (TEM). The XRD characterization of VFeO@g-CN revealed diffraction patterns with a crystallite size of 22.45 nm and a bandgap energy of 1.94 eV. The SEM image revealed the surface to be rough with irregular particle shape and size. The TEM image showed an average particle size of 92.47 nm. VFeO@g-CN exhibited a degradation efficiency, which showed complete removal of SUF (100 %) from solution while the efficiency towards CIP is 94 ± 0.60 % and 90 ± 0.8 % towards ERY. The best photocatalytic performance was achieved with 0.12 g L of VFeO@g-CN and pH = 7.0 as the optimal conditions for achieving complete removal of SUF, CIP and ERY at a concentration lower than 10.00 mg L under visible-light irradiation. The photodegradation of SUF, CIP and ERY by VFeO@g-CN was found to be promoted by ROS with ˙OH and SO˙ radicals playing a significant role. VFeO@g-CN demonstrated a regeneration capacity that is above 90 % at the 10 cycle of regeneration treatment, suggesting it to be stable and reusable with the X-ray diffraction pattern remaining unchanged and no leaching of VFeO@g-CN into solution. The result from the study reveals VFeO@g-CN as a promising photocatalyst for removing antibiotics from an aqueous solution.
PubMed: 38945222
DOI: 10.1016/j.chemosphere.2024.142733