Semi-supervised generative approach to chemical disorder: application to point-defect formation in uranium-plutonium mixed oxides.

Chemical disorder has a major impact on the characterization of the atomic-scale properties of highly complex chemical compounds, such as the properties of point defects. Due to the vast amount of possible atomic configurations, the study of such properties becomes intractable if treated with direct sampling. In this work, we propose an alternative approach, in which samples are selected based on the local atomic composition around the defect, and the defect formation energy is obtained as a function of this local composition with a reduced computational cost. We apply this approach to (U, Pu)O2 nuclear fuels. The formation-energy distribution is computed using machine-learning generative methods, and used to investigate the impact of chemical disorder and the range of influence of local composition on the defect properties. The predicted distributions are then used to calculate the concentration of thermal defects. This approach allows for the first time for the computation of the latter property with a physically meaningful exploration of the configuration space, and opens the way to a more efficient determination of physico-chemical properties in other chemically-disordered compounds such as high-entropy alloys.

Zonal Intratumoral Delivery of Nanoparticles Guided by Surface Functionalization.

Delivery of small molecules and anticancer agents to malignant cells or specific regions within a tumor is limited by penetration depth and poor spatial drug distribution, hindering anticancer efficacy. Herein, we demonstrate control over gold nanoparticle (GNP) penetration and spatial distribution across solid tumors by administering GNPs with different surface chemistries at a constant injection rate via syringe pump. A key finding in this study is the discovery of different zone-specific accumulation patterns of intratumorally injected nanoparticles dependent on surface functionalization. Computed tomography (CT) imaging performed in vivo of C57BL/6 mice harboring Lewis lung carcinoma (LLC) tumors on their flank and gross visualization of excised tumors consistently revealed that intratumorally administered citrate-GNPs accumulate in particle clusters in central areas of the tumor, while GNPs functionalized with thiolated phosphothioethanol (PTE-GNPs) and thiolated polyethylene glycol (PEG-GNPs) regularly accumulate in the tumor periphery. Further, PEG functionalization resulted in larger tumoral surface coverage than PTE, reaching beyond the outer zone of the tumor mass and into the surrounding stroma. To understand the dissimilarities in spatiotemporal evolution across the different GNP surface chemistries, we modeled their intratumoral transport with reaction-diffusion equations. Our results suggest that GNP surface passivation affects nanoparticle reactivity with the tumor microenvironment, leading to differential transport behavior across tumor zones. The present study provides a mechanistic understanding of the factors affecting spatiotemporal distribution of nanoparticles in the tumor. Our proof of concept of zonal delivery within the tumor may prove useful for directing anticancer therapies to regions of biomarker overexpression.

Hybrid Cellular Automata Modeling Reveals the Effects of Glucose Gradients on Tumour Spheroid Growth.

PURPOSE: In recent years, mathematical models have become instrumental in cancer research, offering insights into tumor growth dynamics, and guiding the development of pharmacological strategies. These models, encompassing diverse biological and physical processes, are increasingly used in clinical settings, showing remarkable predictive precision for individual patient outcomes and therapeutic responses. METHODS: Motivated by these advancements, our study introduces an innovative in silico model for simulating tumor growth and invasiveness. The automated hybrid cell emulates critical tumor cell characteristics, including rapid proliferation, heightened motility, reduced cell adhesion, and increased responsiveness to chemotactic signals. This model explores the potential evolution of 3D tumor spheroids by manipulating biological parameters and microenvironment factors, focusing on nutrient availability. RESULTS: Our comprehensive global and local sensitivity analysis reveals that tumor growth primarily depends on cell duplication speed and cell-to-cell adhesion, rather than external chemical gradients. Conversely, tumor invasiveness is predominantly driven by chemotaxis. These insights illuminate tumor development mechanisms, providing vital guidance for effective strategies against tumor progression. Our proposed model is a valuable tool for advancing cancer biology research and exploring potential therapeutic interventions.

MIS-C and co-infection with P. vivax and P. falciparum in a child: a clinical conundrum.

BACKGROUND: The ongoing Coronavirus Disease 2019 (COVID-19) epidemic represents an unprecedented global health challenge. Many COVID-19 symptoms are similar to symptoms that can occur in other infections. Malaria should always be considered in patients with SARS-CoV-2 infection returning from endemic areas. CASE PRESENTATION: We present the first case of multisystem inflammatory syndrome (MIS-C) and Plasmodium vivax-falciparum and SARS-CoV2 coinfection in children. Despite clearance of parassitaemia and a negative COVID-19 nasopharyngeal PCR, the patient's clinical conditions worsened. The World Health Organization (WHO) criteria were used to make the diagnosis of MIS-C. Treatment with intravenous immunoglobulins and methylprednisolone was effective. CONCLUSIONS: This case emphasizes the importance of considering malaria diagnosis in patients returning from endemic areas, even in the COVID 19 era. Malaria and SARS-CoV2 co-infection may increase the risk of MIS-C, for which early detection is critical for proper management.

Migraine in children under 6 years of age: A long-term follow-up study.

BACKGROUND: Early starting of migraine seems predictive for less favorable outcome in later ages, however follow-up investigations are very few and all with short-term prospective period. We report here the longest follow-up study in a population of children presenting with migraine under the age of 6. METHODS: We followed-up 74 children under 6 years of age, referred for headache to our department between 1997 and 2003. The study was carried out between October 2016 and March 2018. Headache diagnoses were made according to the IHS criteria. RESULTS: 23/74 patients, 31% of the original cohort, were found at follow-up in a period ranging between 15 to 21 years after the first visit. Seven of them were headache free. The remaining 16 patients had migraine. In the migraine group, the localization of pain changed in 75% of the subjects, 11/16 (68.7%) had allodynia and 9/16 (56.25%) had cranial autonomic symptoms. CONCLUSIONS: Our results suggest that the onset of migraine at very young age represents unfavorable prognostic factor for persistence of the disease at later ages. Some clinical features may change during clinical course, and the active persistence of the disorder may lead to an increase in allodynia.

Non-invasive Brain Stimulation in Pediatric Migraine: A Perspective From Evidence in Adult Migraine.

Pediatric migraine remains still a challenge for the headache specialists as concerns both diagnostic and therapeutic aspects. The less ability of children to describe the exact features of their migraines and the lack of reliable biomarker for migraine contribute to complicate the diagnostic process. Therefore, there's need for new effective tools for supporting diagnostic and therapeutic approach in children with migraine. Recently, promising results have been obtained in adult headache by means of application of neurostimulation techniques both for investigating pathophysiological mechanisms and also for therapeutical applications. Non-invasive brain stimulation (NIBS) techniques like transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) indeed proved to be generally safe and showing also some evidence of efficacy particularly for the symptomatic treatment. On such basis, in the last years increasing interest is rising in scientific pediatric community to evaluate the potential of such approaches for treatment pediatric headaches, particularly in migraine, even if the evidence provided is still very poor. Here we present a perspective for application of TMS and tDCS technique in children migraine principally based on evidence coming by studies in adults.