Relative Convex Hull Determination from Convex Hulls in the Plane

A new algorithm for the determination of the relative convex hull in the plane of a simple polygon A with respect to another simple polygon B which contains A, is proposed. The relative convex hull is also known as geodesic convex hull, and the problem of its determination in the plane is equivalent to find the shortest curve among all Jordan curves lying in the difference set of B and A and encircling A. Algorithms solving this problem known from Computational Geometry are based on the triangulation or similar decomposition of that difference set. The algorithm presented here does not use such decomposition, but it supposes that A and B are given as ordered sequences of vertices. The algorithm is based on convex hull calculations of A and B and of smaller polygons and polylines, it produces the output list of vertices of the relative convex hull from the sequence of vertices of the convex hull of A.Comment: 15 pages, 4 figures, Conference paper published. We corrected two typing errors in Definition 2: $I_S$ has to be defined based on $O_S$, and $I_E$ has to be defined based on $O_E$ (not just using $O$). These errors appeared in the text of the original conference paper, which also contained the pseudocode of an algorithm where $I_S$ and $I_E$ appeared as correctly define

Barriers to access in pediatric living‐donor liver transplantation

Children receiving a LDLT have superior post‐transplant outcomes, but this procedure is only used for 10% of transplant recipients. Better understanding about barriers toward LDLT and the sociodemographic characteristics that influence these underlying mechanisms would help to inform strategies to increase its use. We conducted an online, anonymous survey of parents/caregivers for children awaiting, or have received, a liver transplant regarding their knowledge and attitudes about LDLT. The survey was completed by 217 respondents. While 97% of respondents understood an individual could donate a portion of their liver, only 72% knew the steps in evaluation, and 69% understood the donor surgery was covered by the recipient's insurance. Individuals with public insurance were less likely than those with private insurance to know the steps for LDLT evaluation (44% vs 82%; P < 0.001). Respondents with public insurance were less likely to know someone that had been a living donor (44% vs 56%; P = 0.005) as were individuals without a college degree (64% vs 85%; P = 0.007). Nearly all respondents generally trusted their healthcare team. Among respondents, 82% believed they were well‐informed about LDLT but individuals with public insurance were significantly less likely to feel well‐informed (67% vs 87%; P = 0.03) and to understand how donor surgery might impact donor work/time off (44% vs 81%; P = 0.001). Substantial gaps exist in parental understanding about LDLT, including its evaluation, potential benefits, and complications. Greater emphasis on addressing these barriers, especially to individuals with fewer resources, will be helpful to expand the use of LDLT

White Matter Tract Pathology in Pediatric Anoxic Brain Injury from Drowning

ABSTRACT BACKGROUND AND PURPOSE: Although drowning is a leading cause of mortality and morbidity in young children, the neuropathologic consequences have not been fully determined. The purpose of this article was to quantitatively characterize white matter microstructural abnormalities in pediatric anoxic brain injury from nonfatal drowning and investigate the correlation with motor function

COVID-19 severity correlates with airway epithelium-immune cell interactions identified by single-cell analysis

To investigate the immune response and mechanisms associated with severe coronavirus disease 2019 (COVID-19), we performed single-cell RNA sequencing on nasopharyngeal and bronchial samples from 19 clinically well-characterized patients with moderate or critical disease and from five healthy controls. We identified airway epithelial cell types and states vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In patients with COVID-19, epithelial cells showed an average three-fold increase in expression of the SARS-CoV-2 entry receptor ACE2, which correlated with interferon signals by immune cells. Compared to moderate cases, critical cases exhibited stronger interactions between epithelial and immune cells, as indicated by ligand–receptor expression profiles, and activated immune cells, including inflammatory macrophages expressing CCL2, CCL3, CCL20, CXCL1, CXCL3, CXCL10, IL8, IL1B and TNF. The transcriptional differences in critical cases compared to moderate cases likely contribute to clinical observations of heightened inflammatory tissue damage, lung injury and respiratory failure. Our data suggest that pharmacologic inhibition of the CCR1 and/or CCR5 pathways might suppress immune hyperactivation in critical COVID-19

Modified physical properties of Ni doped ZnO NPs as potential photocatalyst and antibacterial agents

Hazardous organic dyes, present in the effluents of industries, are continuously polluting the environment. Photodegradation of these dyes on catalyst surface under sunlight irradiation is economic, safe and suitable strategy to protect environment. Hence, the synthesis and applications of Zn1-xNixO (x = 0.00, 0.02, 0.04, 0.06) NPs are reported here. Effect of pH and dopant concentration was studied to modify the electrical, magnetic, antibacterial and photocatalytic properties of Ni doped ZnO NPs. The samples were characterized by Scanning electron microscopy (SEM), Powder X-ray diffraction (XRD), UV–Visible spectroscopy (UV–Vis.), Energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR) to determine the morphology, crystallite structure, optical properties, elemental composition and functional group detection, respectively. LCR meter and VSM were used to evaluate the dielectric properties and magnetic properties of Ni doped ZnO NPs, respectively. XRD pattern confirmed the presence of hexagonal wurtzite geometry of ZnO NPs. The structural and morphological analysis showed the increase in crystallinity with little effect on shape of doped NPs by increasing the dopant concentration and slight increase of pH. It was observed that the Ni doped ZnO NPs possess good photocatalytic potential by 94% degradation of 20 ppm solution of methyl orange dye (MO) in just 80 min under sunlight. Moreover, the enhancement in antibacterial potential was also observed with increase in dopant concentration and decrease in crystallite size of doped ZnO NPs. Smaller size NPs were found more effective against gram negative bacterial strains. © 2023 The Author(s)King Saud University, KSUAuthors would like to extend their sincere appreciation to the Researchers Supporting Project number (RSP2023R123), King Saud University, Riyadh, Saudi Arabia

IL4I1 Is a Metabolic Immune Checkpoint that Activates the AHR and Promotes Tumor Progression

Immune checkpoint blockade therapy induces the AHR-activating enzyme IL4I1, which promotes tumor progression, through its effects on tumor cell motility and adaptive immunity

Clinical profile and treatment of infantile spasms using vigabatrin and ACTH - a developing country perspective

Background: Infantile spasms represent a serious epileptic syndrome that occurs in the early infantile age. ACTH and Vigabatrin are actively investigated drugs in its treatment. This study describes the comparison of their efficacy in a large series of Patients with infantile spasms from Pakistan. Methods: All Patients with infantile spasms who presented to Aga Khan University Hospital, Karachi, Pakistan from January, 2006 to April, 2008 were included in this study. Inclusion criteria were clinical symptoms of infantile spasms, hypsarrythmia or modified hyparrythmia on electroencephalography, at least six months of follow-up period and receipt of any of the two drugs mentioned above. The type of drug distribution was random according to the availability, cost and ease of administration. Results: Fifty six cases fulfilled the inclusion criteria. 62.5% were males. Mean age at onset of seizures was 5 +/- 1.4 months. Fifty two (92.8%) Patients demonstrated hypsarrythmia on electroencephalography. 64.3% cases were identified as symptomatic while 19.6% were cryptogenic and 16.1% were idiopathic. Eighteen Patients received ACTH while 38 Patients received Vigabatrin as first line therapy. Initial response to first line therapy was similar (50% for ACTH and 55.3% for Vigabatrin). Overall, the symptomatic and idiopathic groups responded better to Vigabatrin. The relapse rate was higher for ACTH as compared to Vigabatrin (55.5% vs. 33.3%) when considering the first line therapy. Four Patients evolved to Lennox-Gastaut variant, all of these Patients had initially received Vigabatrin and then ACTH. Conclusion: Vigabatrin and ACTH showed no significant difference in the initial treatment of infantile spasms. However, Patients receiving ACTH were 1.2 times more likely to relapse as compared to the Patients receiving Vigabatrin when considering monotherapy. We suggest that Vigabatrin should be the initial drug of choice in Patients presenting with infantile spasms. However, larger studies from developing countries are required to validate the therapeutic trends observed in this study

MYCN mediates cysteine addiction and sensitizes neuroblastoma to ferroptosis

Aberrant expression of MYC transcription factor family members predicts poor clinical outcome in many human cancers. Oncogenic MYC profoundly alters metabolism and mediates an antioxidant response to maintain redox balance. Here we show that MYCN induces massive lipid peroxidation on depletion of cysteine, the rate-limiting amino acid for glutathione (GSH) biosynthesis, and sensitizes cells to ferroptosis, an oxidative, non-apoptotic and iron-dependent type of cell death. The high cysteine demand of MYCN-amplified childhood neuroblastoma is met by uptake and transsulfuration. When uptake is limited, cysteine usage for protein synthesis is maintained at the expense of GSH triggering ferroptosis and potentially contributing to spontaneous tumor regression in low-risk neuroblastomas. Pharmacological inhibition of both cystine uptake and transsulfuration combined with GPX4 inactivation resulted in tumor remission in an orthotopic MYCN-amplified neuroblastoma model. These findings provide a proof of concept of combining multiple ferroptosis targets as a promising therapeutic strategy for aggressive MYCN-amplified tumors