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The ability of biological and artificial collectives to outperform solitary individuals in a wide variety of tasks depends crucially on the efficient processing of social and environmental information at the level of the collective. Here, we model collective behavior in complex environments with many potentially distracting cues. Counter-intuitively, large-scale coordination in such environments can be maximized by strongly limiting the cognitive capacity of individuals, where due to self-organized dynamics the collective self-isolates from disrupting information. We observe a fundamental trade-off between coordination and collective responsiveness to environmental cues. Our results offer important insights into possible evolutionary trade-offs in collective behavior in biology and suggests novel principles for design of artificial swarms exploiting attentional bottlenecks.

Flocking models with metric and topological interactions are supposed to exhibit distinct features, as for instance the presence and absence of moving polar bands. On the other hand, quenched disorder (spatial heterogeneities) has been shown to dramatically affect large-scale properties of active systems with metric interactions, while the impact of quenched disorder on active systems with metric-free interactions has remained, until now, unexplored. Here, we show that topological flocking models recover several features of metric ones in homogeneous media, when placed in a heterogeneous environment. In particular, we find that order is long-ranged even in the presence of spatial heterogeneities, and that the heterogeneous environment induces an effective density-order coupling facilitating emergence of traveling bands, which are observed in wide regions of parameter space. We argue that such a coupling results from a fluctuation-induced rewiring of the topological interaction network, strongly enhanced by the presence of spatial heterogeneities. While the presence of spatial heterogeneities is known to affect emergent collective behavior in traditional active systems with metric interactions, its role in active systems with nonmetric interactions is still unclear. Here, the authors study the effect of quenched disorder in active matter with topological interactions, finding that topological interactions preserve long-range order in the presence of spatial heterogeneity, which also enhances the emergence of traveling bands.

Background The aim of this study was to evaluate the serum level of matrix metalloproteinase 7 (MMP7) in infants with cholestasis and the diagnostic values of this biomarker to differentiate biliary atresia (BA) from other causes of cholestasis. Methods This multi-center study is conducted during 2 years in Mofid children’s hospital and Children’s Medical Center, Pediatrics Center of Excellence Tehran, Iran. 54 infants with cholestasis were enrolled in this study with a control group consists of 41 healthy infants with the same age. Serum samples were taken from all these patients to assess serum levels of MMP7, Gamma-glutamyl Transferase (GGT). For each biomarker, we calculated the sensitivity and specificity and other statistical characteristics. Results There were 89 subjects, 22 patients with BA, 32 patients with non-BA cholestasis and 41 subjects as control group. The mean serum MMP7 levels in BA, non-BA cholestasis and control group was 15.91 ng/ml ± 6.64, 4.73 ng/ml ± 2.59 and 0.49 ng/ml ± 0.33, respectively. The best cut-off point is calculated 7.8 ng/ml for MMP7 and 434.5 U/L for GGT. The area under curve (AUC) for these two markers are 0.988 ± 0.008 and 0.854 ± 0.052, respectively. The sensitivity and specificity of MMP7 to differentiate biliary atresia from nonbiliary atresia cholestasis in our study was 95.5% and 94.5%, respectively. The sensitivity and specificity of GGT was 77.3% and 77.8%, respectively. These results show that the MMP7 has more sensitivity and specificity in differentiation. Conclusion MMP7 demonstrated good accuracy to differentiate biliary atresia from other causes of cholestasis.

Background: Recurrent abdominal pain (RAP) is one of the frequent complaints in general practice, particularly in pediatrics and is among the common cause of referral to gastroenterology clinics.Purpose: This study is designed to investigate the effects of probiotics for the treatment of RAP and desired therapeutic outcomes.Methods: One hundred twenty-five children with the diagnosis of RAP according to Rome III criteria for irritable bowel syndrome (IBS), functional abdominal pain (FAP), functional dyspepsia (FD), and abdominal migraine (AM), were enrolled in this double-blind randomized controlled trial.Results: Sixty-five subjects received probiotics, and others received placebo treatment for 4 weeks. Lactobacillus reuteri was therapeutically effective in 32 patients compared to 8 patients, responding to the placebo treatment. Compared to baseline, all pain-related variables showed a significant reduction for the IBS and FD at the end of the 4th week. However, it did not respond well in FAP and AM groups. Pain-related outcomes such as, frequency of the pain, severity, and duration of the pain were decreased following the probiotic treatment. No therapeutic response was seen in AM group after the administration of probiotics. L. reuteri significantly led to pain relief in the overall population, and also in FAP, FD, and IBS subgroups.Conclusion: L. reuteri probiotics are likely to lead to RAP relief and can be recommended for the treatment of functional gastrointestinal disorders.

Objective Cystic fibrosis (CF) is a fatal hereditary disorder that leads to respiratory infections and gastrointestinal inflammation with possible association with intestinal dysbiosis. The present study was conducted with the aim of investigating the effects of probiotic consumption in improving pulmonary, gastrointestinal, and growth symptoms in patients with CF. Materials and methods In this double-blind randomized clinical trial, 110 CF patients were examined. Patients were divided into two equal groups of 55 subjects. Patients in the probiotic group consumed Lactobacillus reuteri at the rate of 10 8 CFU/d for one month, and the control group received a placebo. Then, pulmonary, gastrointestinal, and growth-related outcomes as well as quality of life were assessed after one month of intervention as well as at three-month follow-up. Results The results of our study showed that in both intervention and control groups, weight increases significantly after 12 weeks ( P  = 0.01). However, no remarkable difference was reported between the two groups after 12 weeks ( P  = 0.09). In addition, no significant changes were observed between the two groups after 4 and 12 weeks regarding BMI and FEV1. Based on the findings, the score of the CFQ questionnaire in the intervention group increased significantly in the 4th and 12th week. No significant differences were observed between the two groups in terms of factors related to lung function or exacerbations after 12 weeks.The only notable effect reported was related to pain attacks in the probiotic group compared to the placebo group after 4 weeks ( P  = 0.02). Conclusion In general, treatment with probiotics improved the quality of life in patients with CF. However, no significant effect was observed on pulmonary, gastrointestinal, and growth-related outcomes. Trial registration This study was retrospectively registered IRCT registration number: IRCT20240105060622N1 (Registration date: 2024-08-16).

Background: The diagnosis of esophageal varices (EV) is based on the findings of esophagogastroduodenoscopy (EGD), biopsy, and serum markers. Thus, noninvasive cost-effective tests through which high-risk EV children can be diagnosed are needed.Purpose: This cross-sectional study aimed to identify the noninvasive markers for EV in children with liver cirrhosis.Methods: A total of 98 children with liver cirrhosis were evaluated in this study. The spleen size, platelet count, serum albumin, liver function test results, and risk scores were evaluated prior to endoscopy. The endoscopic investigations aimed to identify the presence of EV and red signs, and determine varices sizes.Results: Endoscopy revealed varices in 43 subjects (43.9%). The spleen size, platelet count, international normalized ratio, aspartate aminotransferase to platelet ratio index (APRI), platelet count to spleen size ratio, and risk score differed significantly between patients with and without EV on univariate analysis; however, the logistic regression analysis showed no differences, indicating that none of these parameters were independently associated with the presence of EV.Conclusion: Platelet count, risk score, platelet count to spleen size, and APRI can be useful tools for the identification of highrisk patients with EV and might reduce the need for invasive methods like EGD.

Background Chronic abdominal pain is a potential symptom of lead poisoning, which is often challenging to diagnose. This case–control study aimed to evaluate blood lead levels in pediatric patients with chronic abdominal pain. Methods The case–control study was conducted on 190 pediatrics who presented to the Children's Medical Center Hospital clinics, Tehran between April 2021- 2023. The children were divided into two groups: the case group, consisting of 81 patients with chronic abdominal pain, and the matched control group; 109 children without any gastrointestinal symptoms. The statistical analysis of the data was performed using STATA 16. A multiple logistic regression model was used to assess the association of different independent variables with chronic abdominal pain. Results There was no significant difference between mean (± standard deviation [SD]) of age (8.80(2.7) years vs. control group: 9.23(3.9) years), sex, and BMI (16.55(4.6) vs. 17.32(4.7)) of the patients with chronic abdominal pain (case group) and the control group, whereas the mean weight was remarkably low in patients with chronic abdominal pain: 27.25(± 12.1) kg vs. 31.70(± 14.7) kg ( P value = 0.028). Fifty-nine percent of children with chronic abdominal pain had serum lead levels ≥ 10 µg/dL. The mean (SD) of blood lead levels was statistically high in the case group: 11.09 (± 5.35) µg/dL vs. control group: 8.26 (± 5.01) µg/dL) ( P value ≤ 0.05). The appetite level was significantly low in the case group: 3.8 (± 2.5) vs. control group 5.4 (± 1.3). Conclusions Lead poisoning could be a possible cause of children's chronic abdominal pain. Regarding the high rate of lead poisoning in children exerting appropriate measures to reduce their exposure to lead is necessary.

Diagnosis of cytomegalovirus (CMV) in biopsies relies on detecting classic viral cytopathic effects (CPE) in tissue. These effects are not always apparent, and confirmatory tests are necessary. This study aimed to compare the results of the different diagnostic tests for CMV detection in colitis, including PCR on fresh and formalin-fixed paraffin-embedded (FFPE) tissue, immunohistochemistry (IHC), histology, and plasma PCR, in association with the clinical course. In this prospective study, CMV-PCR was performed on fresh tissue (FT) and FFPE tissue, and IHC was conducted on colon biopsies from 153 children with colitis referred to Children Medical Center Hospital (Tehran, Iran) from 2015 to 2019. The results of different diagnostic methods were evaluated in association with the clinical and histopathological findings. Fifty out of 153 (32%) cases had positive FT-CMV PCR. Forty of these fifty positive samples and 21 of 103 negative ones had concomitant FFPE biopsy tissue. FFPE-PCR and IHC were positive in 17 (42.5 %) and 2 (5%) out of 40 FT-PCR-positive cases, respectively. The two IHC-positive cases had positive FFPE-PCR and high CMV-DNA plasma levels and showed histologically active colitis and CPE. Remarkably, 14 (35%) cases were identified with positive FT-PCR without any evidence of colitis in histopathology. During follow-up, FT-PCR-positive inflammatory bowel disease (IBD) cases treated with antiviral drugs showed a poorer outcome than the non-treated cases (P=0.03). A high positive rate was observed for both FT- and FFPE-CMV PCR, with a poor association with histology. IHC positivity was associated with high plasma CMV DNA levels and the presence of CPE. The efficacy of anti-CMV treatment in colitis cases should be verified through randomized controlled clinical trials. A preprint version of this article is available online at doi: 10.22541/au.168052684.43457923/v1.

Background There is some evidence for the role of vitamin D deficiency in the pathogenesis of inflammatory bowel disease (IBD) in the pediatric population. However, the results are contradictory. Therefore, we have conducted a systematic review and meta-analysis to evaluated the effect of vitamin D on pediatric patients with IBD. Methods We carried out a systematic search in databases from inception until 20 January 2022. We included all relevant articles that evaluate the efficacy and safety of vitamin D on disease activity, inflammatory factors, and vitamin D and calcium levels in pediatric patients with IBD. Random effects models were used to combine the data. The main outcomes were then analyzed using weight mean difference (WMD) and respective 95% confidence interval (CI). Results Fifteen treatment arms met the eligibility criteria and were included. Pooled estimates indicated that intervention with vitamin D has a significantly beneficial effect on 25-hydroxyvitamin D3 [25(OH) D3] (pooled WMD of 17.662 ng/mL; CI 9.77–25.46; P  < 0.001), calcium (pooled WMD of 0.17 mg/dL; CI 0.04–0.30; P  = 0.009), and inflammatory factors including C-reactive protein (CRP) (pooled WMD of −6.57 mg/L; CI −11.47 to −1.67; P  = 0.009) and erythrocyte sedimentation rate (ESR) (pooled WMD of −7.94 mm/h; CI −12.65 to −3.22; P  = 0.001) levels. In addition, this effect was greater for vitamin D levels at doses greater than 2000 IU, and when follow-up duration was more than 12 weeks. Conclusion This study showed that vitamin D therapy can have a significant and beneficial effect on 25(OH) D3, calcium, and inflammatory factors in children and adolescents with IBD.

Objective Bowel preparation can directly affect the final outcome of a colonoscopy. However, limited studies have been conducted regarding the effect of probiotics on intestinal preparation. Thus, the present study aims to investigate the effect of Lactobacillus reuteri probiotics in the bowel preparation regimen of children who are candidates for colonoscopy. Methods and Materials In this double‐blind, placebo‐controlled, randomized clinical trial, 84 colonoscopy candidate pediatric patients were enrolled. Patients were divided into two equal groups of 42 individuals. One group of patients underwent the bisacodyl, polyethylene glycol regimen 48 h before colonoscopy, as along with a placebo. The other group was administered L. reuteri 10 days before colonoscopy and also received bisacodyl and polyethylene glycol 48 h before the procedure. Then, the bowel preparation of the patients was assessed using the Boston Bowel Preparation Scale (BBPS). Results The mean age of patients in the placebo and probiotic groups was 94.1 ± 43.8 and 111.2 ± 48.8 months, respectively (p = 0.10). The preparation of the left colon was not significantly different between the placebo and probiotic groups (p = 0.075). The effect of L. reuteri probiotic on the preparation of the right colon was excellent in 18 patients (42.86%) and good in 17 patients (40.47%). The preparation of the right colon was significantly different between the placebo and probiotic groups (p = 0.007). Based on the results, there was a significant association between the consumption of L. reuteri and placebo in the preparation of the transverse colon (p = 0.015). Conclusion Probiotic pretreatment as part of bowel preparation significantly improves visualization of the colonic mucosa during colonoscopy.