Rate-splitting Multiple Access for Hierarchical HAP-LAP Networks under Limited Fronthaul

In this correspondence, we propose hierarchical high-altitude platform (HAP)-low-altitude platform (LAP) networks with the aim of maximizing the sum-rate of ground user equipments (UEs). The multiple aerial radio units (RUs) mounted on HAPs and LAPs are managed by the central unit (CU) via constrained fronthaul links. The limitation of fronthaul capacity can be addressed through quantization, employing the cloud radio access network (C-RAN) architecture. For spectral efficiency, we adopt the rate-splitting multiple access (RSMA), leveraging the advantages of both space-division multiple access (SDMA) and non-orthogonal multiple access (NOMA). To achieve this, we jointly optimize rate splitting, transmit power allocation, quantization noise variance, and UAV placement using an alternating optimization (AO) approach coupled with successive convex approximation (SCA) and the weighted minimum mean square error (WMMSE) method. Numerical results validate the superior performance of the proposed method compared to benchmark schemes, including partial optimizations or those without the assistance of LAPs

Higher induction and maintenance infliximab trough levels are associated with radiological perianal fistula healing in pediatric patients with Crohn's disease

BackgroundLiterature on the association between high infliximab (IFX) trough levels and perianal fistula response in pediatric patients with perianal fistulizing Crohn's disease (PFCD) is limited. This study aimed to evaluate the association between IFX trough levels and radiological perianal fistula healing in pediatric patients with PFCD undergoing long-term IFX treatment.MethodsThe study included pediatric patients (aged <18 years) diagnosed with PFCD who received IFX treatment and underwent follow-up magnetic resonance imaging (MRI) at 1 year. The primary outcome was radiological fistula healing on MRI one year after IFX treatment.ResultsA total of 82 patients were included and 57 (69.5%) achieved radiological fistula healing at the 1-year follow-up. Patients with radiological fistula healing had lower rates of reoperation (p = 0.021), and higher median IFX trough levels at week 2 (median, 17.6 vs. 14.1 μg/ml), week 6 (11.79 vs. 7.11 μg/ml), week 30 (3.9 vs. 1.1 μg/ml), and week 54 (7.6 vs. 3.7 μg/ml) (p = 0.043, 0.003, 0.007 and <0.001, respectively) compared to those who had no fistula healing. In the multivariate analysis, higher median IFX trough levels at week 6 and week 54 remained significant factors associated with radiological fistula healing (p = 0.039 and 0.018, respectively). Optimal cut-off IFX trough levels for radiological fistula healing showing the highest area under curve (AUC) score was 9.7 μg/ml [AUC: 0.792, 95% confidence interval (CI): 0.630–0.955; p = 0.005] for week 6, and 5.1 μg/ml (AUC, 0.848; 95% CI: 0.750–0.947; p < 0.001) for week 54.ConclusionThere was a significant association between higher serum IFX trough levels (during induction and maintenance) and radiological perianal fistula healing after 1 year of IFX treatment in pediatric patients with PFCD

Two-stage learning-based prediction of bronchopulmonary dysplasia in very low birth weight infants: a nationwide cohort study

IntroductionThe aim of this study is to develop an enhanced machine learning-based prediction models for bronchopulmonary dysplasia (BPD) and its severity through a two-stage approach integrated with the duration of respiratory support (RSd) using prenatal and early postnatal variables from a nationwide very low birth weight (VLBW) infant cohort.MethodsWe included 16,384 VLBW infants admitted to the neonatal intensive care unit (NICU) of the Korean Neonatal Network (KNN), a nationwide VLBW infant registry (2013–2020). Overall, 45 prenatal and early perinatal clinical variables were selected. A multilayer perceptron (MLP)-based network analysis, which was recently introduced to predict diseases in preterm infants, was used for modeling and a stepwise approach. Additionally, we applied a complementary MLP network and established new BPD prediction models (PMbpd). The performances of the models were compared using the area under the receiver operating characteristic curve (AUROC) values. The Shapley method was used to determine the contribution of each variable.ResultsWe included 11,177 VLBW infants (3,724 without BPD (BPD 0), 3,383 with mild BPD (BPD 1), 1,375 with moderate BPD (BPD 2), and 2,695 with severe BPD (BPD 3) cases). Compared to conventional machine learning (ML) models, our PMbpd and two-stage PMbpd with RSd (TS-PMbpd) model outperformed both binary (0 vs. 1,2,3; 0,1 vs. 2,3; 0,1,2 vs. 3) and each severity (0 vs. 1 vs. 2 vs. 3) prediction (AUROC = 0.895 and 0.897, 0.824 and 0.825, 0.828 and 0.823, 0.783, and 0.786, respectively). GA, birth weight, and patent ductus arteriosus (PDA) treatment were significant variables for the occurrence of BPD. Birth weight, low blood pressure, and intraventricular hemorrhage were significant for BPD ≥2, birth weight, low blood pressure, and PDA ligation for BPD ≥3. GA, birth weight, and pulmonary hypertension were the principal variables that predicted BPD severity in VLBW infants.ConclusionsWe developed a new two-stage ML model reflecting crucial BPD indicators (RSd) and found significant clinical variables for the early prediction of BPD and its severity with high predictive accuracy. Our model can be used as an adjunctive predictive model in the practical NICU field

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Impact of posterior wall repair and mesh use on recurrence in inguinal hernia repair for adolescents and young adults

Objective: The study aimed to evaluate the efficacy of mesh use and posterior wall repair (PWR) during inguinal hernia repair in adolescents and young adults. Methods: A total of 29,149 patients aged 12 to 30 who underwent inguinal hernia repair were selected from the Korean National Health Insurance claims data. Patients were divided into two groups: 12–18 years old and 19–30 years old. The recurrence rate and prevalence of chronic pain were compared depending on whether PWR was performed or mesh was used. Results: The recurrence rates between high ligation and high ligation with PWR were not significantly different in both groups (2.3 % vs. 2.6 %; 2.6 % vs. 3.0 %; p = 0.285 and 0.168 for patients aged 12–18 and 19–30, respectively). The use of mesh was associated with a reduced recurrence rate in patients aged 19–30 (3.1 % vs. 1.9 % in no mesh vs. mesh use; p = 0.005); however, it was not significant in patients aged 12–18 (2.7 % vs. 2.1 % in no mesh vs. mesh use; p = 0.541). In multivariate analysis, nonuse of mesh was an independently significant factor associated with recurrence in patients aged 19–30, with an odds ratio of 0.62 (95 % confidence interval = 0.44–0.90; p = 0.01). Mesh use and PWR were not significant factor associated with chronic pain in all age groups. Conclusion: The results of our study indicate that the use of mesh is associated with a lower recurrence rate in young adults (aged 19–30) undergoing inguinal hernia surgery. However, no such association was observed in adolescents (aged 12–18)

Risk Factors for Postoperative Intra-Abdominal Abscess in Pediatric Perforated Appendicitis Following Laparoscopic Appendectomy: A Multicenter Analysis

Background: Perforated appendicitis in children is a frequently encountered and significant surgical condition. The treatment of choice is laparoscopic appendectomy, but this carries a risk of postoperative intra-abdominal abscess (IAA). The purpose of this study was to determine risk factors linked to the occurrence of IAA following laparoscopic surgery in pediatric perforated appendicitis. Methods: This retrospective cohort study analyzed 137 children with perforated appendicitis who received laparoscopic appendectomy at four tertiary hospitals between March 2018 and December 2022. Data on patient demographics, preoperative clinical characteristics, and surgical details were collected. Independent risk factors for IAA formation were determined using logistic regression analysis. Results: The overall incidence of postoperative IAA was 10.9%. Prolonged symptom duration and elevated CRP levels were associated with higher IAA rates. Patients who developed IAAs experienced prolonged postoperative fevers and longer hospital stays. Significant risk factors for IAA identified through multivariable analysis included a higher severity grade of appendicitis (&ge;Grade IV, OR 5.9, p = 0.034) and the presence of a free appendicolith during surgery (OR 5.549, p = 0.01). Of the patients who developed IAAs, nine (60%) improved with conservative treatment, while six (40%) required invasive procedures. Conclusions: A higher severity grade of appendicitis (&ge;Grade IV) and the presence of a free appendicolith are significant predictors of postoperative IAAs in pediatric perforated appendicitis. Recognizing these factors can help guide clinical management and postoperative care, potentially reducing the incidence of this complication

Features of colonic diverticulitis in children and adolescents: A multicenter study

Summary: Background: Colonic diverticulitis (CD), typically seen in the elderly of Western countries, is increasingly prevalent worldwide, yet data on CD in children and adolescents are scarce. This study explores the characteristics of CD in this younger demographic. Methods: In a multicenter, retrospective review, 104 patients under 20 years diagnosed with CD at four Korean tertiary hospitals from June 2003 to December 2020 were analyzed. Abdominal CT scans were used for diagnosis, with the modified Hinchey classification assessing the severity of CD. Results: CD was found in the cecum or ascending colon in 103 (99%) of cases. The mean patient age was 17.24 ± 2.4 years, with males constituting 59.6% of cases. Solitary lesions were noted in 93 (89.4%) of patients. Severity was classified as modified Hinchey stage 0 in 58.7%, stage Ia in 29.8%, and stage Ib in 11.5%, with no cases of stage II or higher. Misdiagnosis as acute appendicitis occurred in six instances. IV antibiotics were administered to 68.3%, and oral antibiotics were sufficient for 24%. Surgical treatment was necessary for two patients. A 7.8% recurrence rate was noted among first-time CD patients, yet all cases were amenable to conservative management. Conclusion: While uncommon, CD in children and adolescents is a growing concern, with most cases presenting as solitary lesions in the cecum or ascending colon. The severity is typically less than that in adults, and conservative treatment is generally effective. These findings underscore the need for specific management guidelines for pediatric CD, advocating for non-surgical initial approaches

Prediction of Recurrence of Completely Resected Pancreatic Solid Pseudopapillary Neoplasms in Pediatric Patients: A Single Center Analysis

Background: Many previous studies have investigated the risk factors for the recurrence of pancreatic solid pseudopapillary neoplasms (SPNs), although a consensus has not yet been reached, despite this effort. We aimed to identify the predictive factors for recurrence in patients with SPNs who underwent complete surgical resection of the tumor. Methods: We retrospectively analyzed the records of pediatric patients with SPNs who underwent surgical resection at a single center between 2001 and 2018. Results: During the study period, 47 patients with SPNs underwent radical resection of the tumor. The median age of the patients was 14 (8–18) years. R0 resection was confirmed in every case and none of the patients presented with systemic metastasis at the time of diagnosis. The median follow-up period was 53.1 (30.8–150.8) months. Of the 47 patients, only two (4.2%) experienced recurrence. Using comparative analysis, we found that some factors such as a large tumor size, peripancreatic tissue invasion, and capsule invasion did not increase the risk of recurrence of SPNs. Lymph node metastasis was the only significant factor for recurrence in our study (p = 0.043). Conclusion: During our single center analysis, we found that only lymph node metastasis was a predictive factor for recurrence of SPNs among patients who underwent complete tumor resection. Long-term follow-up is required to determine whether SPNs will recur if lymph node metastasis is observed after surgery. Furthermore, therapeutic benefits of routine lymphadenectomy or sentinel lymph node biopsy should be investigated in future studies to reduce the risk of recurrence in patients with SPNs.</jats:p

Prediction of Recurrence of Completely Resected Pancreatic Solid Pseudopapillary Neoplasms in Pediatric Patients: A Single Center Analysis

Background: Many previous studies have investigated the risk factors for the recurrence of pancreatic solid pseudopapillary neoplasms (SPNs), although a consensus has not yet been reached, despite this effort. We aimed to identify the predictive factors for recurrence in patients with SPNs who underwent complete surgical resection of the tumor. Methods: We retrospectively analyzed the records of pediatric patients with SPNs who underwent surgical resection at a single center between 2001 and 2018. Results: During the study period, 47 patients with SPNs underwent radical resection of the tumor. The median age of the patients was 14 (8–18) years. R0 resection was confirmed in every case and none of the patients presented with systemic metastasis at the time of diagnosis. The median follow-up period was 53.1 (30.8–150.8) months. Of the 47 patients, only two (4.2%) experienced recurrence. Using comparative analysis, we found that some factors such as a large tumor size, peripancreatic tissue invasion, and capsule invasion did not increase the risk of recurrence of SPNs. Lymph node metastasis was the only significant factor for recurrence in our study (p = 0.043). Conclusion: During our single center analysis, we found that only lymph node metastasis was a predictive factor for recurrence of SPNs among patients who underwent complete tumor resection. Long-term follow-up is required to determine whether SPNs will recur if lymph node metastasis is observed after surgery. Furthermore, therapeutic benefits of routine lymphadenectomy or sentinel lymph node biopsy should be investigated in future studies to reduce the risk of recurrence in patients with SPNs