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Nature Communications Jun 2024When particles are deposited at a fluid interface they tend to aggregate by capillary attraction to minimize the overall potential energy of the system. In this work, we...
When particles are deposited at a fluid interface they tend to aggregate by capillary attraction to minimize the overall potential energy of the system. In this work, we embed floating millimetric disks with permanent magnets to introduce a competing repulsion effect and study their pattern formation in equilibrium. The pairwise energy landscape of two disks is described by a short-range attraction and long-range repulsion (SALR) interaction potential, previously documented in a number of microscopic condensed matter systems. Such competing interactions enable a variety of pairwise equilibrium states, including the possibility of a local minimum energy corresponding to a finite disk spacing. Two-dimensional (2D) experiments and simulations in confined geometries demonstrate that as the areal packing fraction is increased, the dilute repulsion-dominated lattice state becomes unstable to the spontaneous formation of localized clusters, which eventually merge into a system-spanning striped pattern. Finally, we demonstrate that the equilibrium pattern can be externally manipulated by the application of a supplemental vertical magnetic force that remotely enhances the effective capillary attraction.
PubMed: 38937449
DOI: 10.1038/s41467-024-49754-4 -
Metallomics : Integrated Biometal... Jun 2024Bacterial biofilms are associated with antibiotic resistance and account for approximately 80% of all bacterial infections. In this study, we explored novel...
Bacterial biofilms are associated with antibiotic resistance and account for approximately 80% of all bacterial infections. In this study, we explored novel nanomaterials for combating bacteria and their biofilms. Artemisinin nano-copper (ANC) was synthesised using a green synthesis strategy, and its shape, size, structure, elemental composition, chemical valence, zeta potential, and conductivity were characterised using transmission electron microscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, zeta potential, and dynamic light scattering (DLS). The results showed that ANC was successfully synthesised utilizing a liquid-phase chemical reduction method using chitosan as a modified protectant and l-ascorbic acid as a green reducing agent. The stability of ANC was evaluated using DLS. The results showed that the particle size of the ANC at different concentrations was comparable to that of the original solution after 7 days of storage, and there was no significant change in PDI (P > 0.05). The antibacterial effects of ANC on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were determined by Disk diffusion and broth dilution methods. The results demonstrated that ANC inhibited and killed E. coli and S. aureus. The effect of ANC on bacterial biofilms was investigated using Crystal Violet staining, scanning electron microscopy, laser confocal microscope, and quantitative PCR. The results showed that ANC treatment was able to destroy bacterial biofilms and downregulate biofilm- and virulence-related genes in E. coli (HlyA, gyrA, and F17) and S. aureus (cna, PVL, ClfA, and femB). Green-synthesised ANC possesses excellent anti-biofilm properties and is expected to exhibit antibacterial and anti-biofilm properties.
PubMed: 38936831
DOI: 10.1093/mtomcs/mfae030 -
Medical Physics Jun 2024Combining the sharp dose fall off feature of beta-emitting Ru/Rh radionuclide with larger penetration depth feature of photon-emittingI radionuclide in a bi-radionuclide...
BACKGROUND
Combining the sharp dose fall off feature of beta-emitting Ru/Rh radionuclide with larger penetration depth feature of photon-emittingI radionuclide in a bi-radionuclide plaque, prescribed dose to the tumor apex can be delivered while maintaining the tumor dose uniformity and sparing the organs at risk. The potential advantages of bi-radionuclide plaque could be of interest in context of ocular brachytherapy.
PURPOSE
The aim of the study is to evaluate the dosimetric advantages of a proposed bi-radionuclide plaque for two different designs, consisting of indigenous I seeds and Ru/Rh plaque, using Monte Carlo technique. The study also explores the influence of other commercial I seed models and presence or absence of silastic/acrylic seed carrier on the calculated dose distributions. The study further included the calculation of depth dose distributions for the bi-radionuclide eye plaque for which experimental data are available.
METHODS
The proposed bi-radionuclide plaque consists of a 1.2-mm-thick silver (Ag) spherical shell with radius of curvature of 12.5 mm, 20 µm-thick-Ru/Rh encapsulated between 0.2 mm Ag disk, and a 0.1-mm-thick Ag window, and water-equivalent gel containing 12 symmetrically arranged I seeds. Two bi-radionuclide plaque models investigated in the present study are designated as Design I and Design II. In Design I, I seeds are placed on the top of the plaque, while in Design II Ru/Rh source is positioned on the top of the plaque. In Monte Carlo calculations, the plaque is positioned in a spherical water phantom of 30 cm diameter.
RESULTS
The proposed bi-radionuclide eye plaque demonstrated superior dose distributions as compared to I or Ru plaque for tumor thicknesses ranges from 5 to 10 mm. Amongst the designs, dose at a given voxel for Design I is higher as compared to the corresponding voxel dose for Design II. This difference is attributed to the higher degree of attenuation of I photons in Ag as compared to beta particles. Influence of different I seed models on the normalized lateral dose profiles of Design I (in the absence of carrier) is negligible and within 5% on the central axis depth dose distribution as compared to the corresponding values of the plaque that has indigenous I seeds. In the presence of a silastic/acrylic seed carrier, the normalized central axis dose distributions of Design I are smaller by 3%-12% as compared to the corresponding values in the absence of a seed carrier. For the published bi-radionuclide plaque model, good agreement is observed between the Monte Carlo-calculated and published measured depth dose distributions for clinically relevant depths.
CONCLUSION
Regardless of the type of I seed model utilized and whether silastic/acrylic seed carrier is present or not, Design I bi-radionuclide plaque offers superior dose distributions in terms of tumor dose uniformity, rapid dose fall off and lesser dose to nearby critical organs at risk over the Design II plaque. This shows that Design I bi-radionuclide plaque could be a promising alternative to I plaque for treatment of tumor sizes in the range 5 to 10 mm.
PubMed: 38935327
DOI: 10.1002/mp.17257 -
Frontiers in Neuroscience 2024The Human Connectome Project (HCP) has become a keystone dataset in human neuroscience, with a plethora of important applications in advancing brain imaging methods and...
INTRODUCTION
The Human Connectome Project (HCP) has become a keystone dataset in human neuroscience, with a plethora of important applications in advancing brain imaging methods and an understanding of the human brain. We focused on tractometry of HCP diffusion-weighted MRI (dMRI) data.
METHODS
We used an open-source software library (pyAFQ; https://yeatmanlab.github.io/pyAFQ) to perform probabilistic tractography and delineate the major white matter pathways in the HCP subjects that have a complete dMRI acquisition ( = 1,041). We used diffusion kurtosis imaging (DKI) to model white matter microstructure in each voxel of the white matter, and extracted tract profiles of DKI-derived tissue properties along the length of the tracts. We explored the empirical properties of the data: first, we assessed the heritability of DKI tissue properties using the known genetic linkage of the large number of twin pairs sampled in HCP. Second, we tested the ability of tractometry to serve as the basis for predictive models of individual characteristics (e.g., age, crystallized/fluid intelligence, reading ability, etc.), compared to local connectome features. To facilitate the exploration of the dataset we created a new web-based visualization tool and use this tool to visualize the data in the HCP tractometry dataset. Finally, we used the HCP dataset as a test-bed for a new technological innovation: the TRX file-format for representation of dMRI-based streamlines.
RESULTS
We released the processing outputs and tract profiles as a publicly available data resource through the AWS Open Data program's Open Neurodata repository. We found heritability as high as 0.9 for DKI-based metrics in some brain pathways. We also found that tractometry extracts as much useful information about individual differences as the local connectome method. We released a new web-based visualization tool for tractometry-"Tractoscope" (https://nrdg.github.io/tractoscope). We found that the TRX files require considerably less disk space-a crucial attribute for large datasets like HCP. In addition, TRX incorporates a specification for grouping streamlines, further simplifying tractometry analysis.
PubMed: 38933816
DOI: 10.3389/fnins.2024.1389680 -
Frontiers in Veterinary Science 2024A spayed, 8-year-old female Poodle, weighing 5.7 kg, was presented with the chief complaint of vision impairment. Vision assessment, including pupillary light...
Case report: Unilateral papilledema in a dog with a large suprasellar mass and suspected intracranial hypertension: insights from funduscopy, optical coherence tomography, and magnetic resonance imaging.
A spayed, 8-year-old female Poodle, weighing 5.7 kg, was presented with the chief complaint of vision impairment. Vision assessment, including pupillary light reflexes, menace response, dazzle reflex, and maze navigation in photopic and scotopic circumstances, revealed a negative response in both eyes except for positive direct pupillary light reflex in the right eye and positive consensual pupillary light reflex from the right eye to the left eye. Systemic evaluation, including neurologic status, blood profile, and thoracic radiographs, did not reveal any abnormalities. Complete ophthalmic examinations, ocular ultrasonography, and electroretinography did not identify a cause of blindness. Upon funduscopy, the left eye exhibited an increased optic disk diameter, blurred optic disk borders, and loss of the physiologic pit, as well as an increase in vascular tortuosity. In the right eye, there were multifocal depigmented areas in the non-tapetal fundus and several pigmented spots surrounded by a region of dull tapetal reflection in the tapetal fundus. The optical coherence tomography revealed severe anterior deformation of the optic nerve head and Bruch's membrane in the peripapillary region of the left eye. Magnetic resonance imaging revealed an irregular, broad-based suprasellar mass, with features suggestive of intracranial hypertension, including dorsal displacement of third ventricles, a rightward shift of the falx cerebri, -tentorial herniation, perilesional edema, flattening/protrusion of the posterior sclera, and lager optic nerve sheath diameter in left side than right side. This is the first comprehensive report that describes unilateral papilledema in a dog with a brain tumor, using advanced ophthalmic and neuro-imaging modalities.
PubMed: 38933701
DOI: 10.3389/fvets.2024.1372802 -
Ecology and Evolution Jun 2024The equilibrium theory of island biogeography (ETIB) is a widely applied dynamic theory proposed in the 1960s to explain why islands have coherent differences in species...
The equilibrium theory of island biogeography (ETIB) is a widely applied dynamic theory proposed in the 1960s to explain why islands have coherent differences in species richness. The development of the ETIB was temporarily challenged in the 1970s by the alternative static theory of ecological impoverishment (TEI). The TEI suggests that the number of species on an island is determined by its number of habitats or niches but, with no clear evidence relating species richness to the number of niches however, the TEI has been almost dismissed as a theory in favour of the original ETIB. Here, we show that the number of climatic niches on islands is an important predictor of the species richness of plants, herpetofauna and land birds. We therefore propose a model called the niche-based theory of island biogeography (NTIB), based on the MacroEcological Theory on the Arrangement of Life (METAL), which successfully integrates the number of niches sensu Hutchinson into ETIB. To account for greater species turnover at the beginning of colonisation, we include higher initial extinction rates. When we test our NTIB for resident land birds in the Krakatau Islands, it reveals a good correspondence with observed species richness, immigration and extinction rates. Provided the environmental regime remains unchanged, we estimate that the current species richness at equilibrium is ~45 species (range between 38.39 and 61.51). Our NTIB provides better prediction because it counts for changes in species richness with latitude, which is not considered in any theory of island biogeography.
PubMed: 38932973
DOI: 10.1002/ece3.11540 -
Pharmaceutics May 2024(1) Background: Antimicrobial resistance is growing at an extreme pace and has proven to be an urgent topic, for research into alternative treatments. Such a prospective...
(1) Background: Antimicrobial resistance is growing at an extreme pace and has proven to be an urgent topic, for research into alternative treatments. Such a prospective possibility is hidden in antimicrobial peptides because of their low to no toxicity, effectiveness at low concentrations, and most importantly their ability to be used for multiple treatments. This work was focused on the study of the effect of the modification in position 7 of Temporin A on its biological activity; (2) Methods: The targeted peptides were synthesized using Fmoc/O-Bu SPPS. The antibacterial activity of the analogs was determined using the broth microdilution method and disk-diffusion method. In vitro tests were performed to determine the cytotoxicity, phototoxicity, and antiproliferative activity of the peptide analogs on a panel of tumor and normal cell lines; (3) Results: All analogs except DTCit showed good antibacterial activity, with DTDab having the best activity according to the disk-diffusion method. However, DTCit had an acceptable cytotoxicity, combined with good selectivity against the test MCF-7 cell line; (4) Conclusions: The obtained results revealed the importance of the basicity and length of the side chain at position 7 in the Temporin A sequence for both tested activities.
PubMed: 38931840
DOI: 10.3390/pharmaceutics16060716 -
Pharmaceuticals (Basel, Switzerland) Jun 2024Urinary tract infections (UTIs) are a widespread condition in pets, with many antibiotics being prescribed, contributing to the rise in antimicrobial resistance, which...
Urinary tract infections (UTIs) are a widespread condition in pets, with many antibiotics being prescribed, contributing to the rise in antimicrobial resistance, which is a worldwide threat. This study's main objective was to analyze the in vitro antimicrobial activity of and fruit hydro-ethanolic extracts towards bacteria identified in the urine of companion animals experiencing UTIs. Urine samples were collected from dogs and cats ( = 83; 47 negative, 36 positive); several bacterial strains were identified ( = 49) belonging to the , , , , , , , , , and genera. Bacterial susceptibility was tested using the disk diffusion method, with the majority being resistant to several beta-lactams, quinolones, trimethoprim/sulfamethoxazole, and nitrofurantoin. Subsequently, 13 resistant isolates were selected to evaluate the fruits extracts' antimicrobial potential using the agar well diffusion and broth microdilution methods. exhibited the greatest activity against Gram-negatives (primarily ), while showed maximum effects towards Gram-positives (particularly ). The MIC was 0.01 μg/μL for both extracts; the MBC was 0.08 μg/μL for and 0.05 μg/μL for . However, showed a stronger bactericidal effect. This is the first study to investigate these fruit extracts in UTI isolates of companion animals, and these extracts might be used as substitutes or adjuvants for antibiotics, thus contributing to a reduction in antimicrobial resistance.
PubMed: 38931481
DOI: 10.3390/ph17060814 -
Pharmaceuticals (Basel, Switzerland) Jun 2024The emergence of antibiotic resistance, caused by the improper use of antibiotics, is a significant challenge in combating infectious diseases, leading to millions of...
The emergence of antibiotic resistance, caused by the improper use of antibiotics, is a significant challenge in combating infectious diseases, leading to millions of annual fatalities. The occurrence of antimicrobial side effects catalyzes the investigation of novel antimicrobial compounds and sources of drugs. Consequently, the research on biological activity that is conducted on plants, plant extracts, and compounds that are produced from plant components is of utmost significance. In this study, CtAC/MNPs were obtained by the reaction of activated carbon (AC) obtained from the fruits of the (Ct) plant and magnetic nanoparticles (MNPs), and a CtAC/MNPs-Ag nanocomposite was synthesized by the reduction in silver ions added to the reaction. The synthesized CtAC/MNPs and CtAC/MNPs-Ag nanocomposites were analyzed spectroscopically (FTIR, XRD), microscopically (SEM, EDX), optically (DLS), electrochemically (zeta potential) and magnetically (VSM). The antibacterial activities of CtAC/MNPs and CtAC/MNPs-Ag nanocomposites against and were investigated by microdilution method using minimal inhibitory concentration (MIC) and disk diffusion methods. Antioxidant activity study, including total phenolic content and DPPH and cuprac assays, revealed the remarkable effect of the CtAC/MNPs-Ag nanocomposite. This study has the advantages of obtaining CtAC/MNPs and CtAC/MNPs-Ag nanocomposites in a short time without requiring energy, and most importantly, the reaction takes place without using any toxic substances. In addition, according to the data obtained in the study, the CtAC/MNPs-Ag nanocomposite is thought to shed light on biomedical research.
PubMed: 38931439
DOI: 10.3390/ph17060772 -
Pharmaceuticals (Basel, Switzerland) May 2024Carbapenem antibiotic resistance is an emerging medical concern. Bacteria that possess the carbapenemase (KPC) protein, an enzyme that catalyzes the degradation of...
Carbapenem antibiotic resistance is an emerging medical concern. Bacteria that possess the carbapenemase (KPC) protein, an enzyme that catalyzes the degradation of carbapenem antibiotics, have exhibited remarkable resistance to traditional and even modern therapeutic approaches. This study aimed to identify potential natural drug candidates sourced from the leaves of (). The phytoconstituents present in dried leaves were extracted using ethanol 80%. A reasonable amount of the extract was used to identify these phytochemicals via gas chromatography/mass spectrometry (GC/MS). One hundred twenty-two bioactive compounds from were identified and subjected to docking analysis against the target bacterial protein. Four compounds (PubChem CID: 6917974, 159099, 628694, and 482788) were selected based on favorable docking scores (-9, -7.8, -7.7, and -7.5 kcal/mol). This computational investigation highlights the potential of these four compounds as promising antibacterial candidates against the specific PC protein. Additionally, in vitro antibacterial assays using extracts were conducted. The minimum inhibitory concentration (MIC) against the bacterium was 125 μg/mL. Well-disk diffusion tests exhibited inhibition zones ranging from 10.3 ± 0.5 mm to 17 ± 0.5 mm at different concentrations, and time-kill kinetics at 12 h indicated effective inhibition of bacterial growth by leaf extracts. Our findings have revealed the pharmaceutical potential of as a natural source for drug candidates against carbapenem-resistant pathogens.
PubMed: 38931335
DOI: 10.3390/ph17060667