Large-deviation theory of increasing returns.

An influential theory of increasing returns was proposed by the economist W. B. Arthur in the 1980s to explain the lock-in phenomenon between two competing commercial products. In the most simplified situation there are two competing products that gain customers according to a majority mechanism: each new customer arrives and asks which product they bought to a certain odd number of previous customers, and then buys the most shared product within this sample. It is known that one of these two companies becomes a monopoly almost surely in the limit of infinite customers. Here we consider a generalization [Dosi, Ermoliev, and Kaniovsky, J. Math. Econom. 23, 1 (1994)10.1016/0304-4068(94)90032-9] in which the new customer follows the indication of the sample with some probability, and buys the other product otherwise. Other than economy, this model can be reduced to the urn of Hill, Lane, and Sudderth, and it includes several models of physical interest as special cases, such as the Elephant Random Walk, Friedman's urn, and other generalized urn models. We provide a large-deviation analysis of this model at the sample-path level, and we provide a formula that allows us to find the most likely trajectories followed by the market share variable. Interestingly, in the parameter range where the lock-in phase is expected, we observe a whole region of convergence where the entropy cost is sublinear. We also find a nonlinear differential equation for the cumulant-generating function of the market share variable, which can be studied with a suitable perturbation theory.

Fear of hypoglycemia in children with type 1 diabetes and their parents: Validation of the Italian version of the Hypoglycemia Fear Survey for Children and for Parents.

BACKGROUND: Currently, Italian versions of the Hypoglycemia Fear Survey for Children (CHFS) and for Parents (PHFS) quantifying Fear of Hypoglycemia (FoH) in pediatric diabetes are not available. OBJECTIVE: To validate the Italian version of the CHFS and PHFS. SUBJECTS AND METHODS: One hundred and seventy-four children with type 1 diabetes aged 6-18 and 178 parents completed the CHFS and PHFS, the PedsQL 3.0 Diabetes module and the KIDSCREEN-10. Internal consistency was good (α = 0.85 for CHFS, α = 0.88 for PHFS); validity was supported by correlations of CHFS total score (CHFS-T r = -0.50; p < 0.001, CI = -0.62 to -0.35) and Worry subscale (CHFS-W r = -0.49; p < 0.001, CI = -0.62 to -0.32) with measures of health-related quality of life (QoL), which were not related to PHFS scores. Factor analyses justified the structure and the separate scoring of Behavior and Worry subscales. Children's age was negatively correlated with CHFS-T (r = -0.16; p = 0.03, CI = -0.36 to 0.00), CHFS-W (r = -0.29; p = 0.02, CI = -0.39 to -0.07), PHFS-T (r = -0.20; p = 0.006, CI = -0.35 to -0.04), PHFS-B (r = -0.30; p = 0.001, CI = -0.43 to -0.17). Mean (SD) item scores of CHFS-T (1.47 ± 0.56 vs. 1.27 ± 0.57; p < 0.05) and CHFS-W (1.20 ± 0.73 vs. 0.96 ± 0.68; p < 0.05) were higher in children with HbA1c ≥7.5%. Higher levels of distress for upsetting hypoglycemia were associated with lower child's QoL scores as perceived by children (Peds-QL: 72.6 ± 12.8 vs. 80.4 ± 11.9; p < 0.001) and parents (Peds-QL: 70.6 ± 13.8 vs. 75.8 ± 12.9; p < 0.05). CONCLUSION: The Italian version of CHFS and PHFS appears to be a valid measure to assess FoH in clinical practice and factor analysis supports separate scoring for the Worry and Behavior subscales.

Energy of the interacting self-avoiding walk at the θ point.

We perform a numerical study of a new microcanonical polymer model on a three-dimensional cubic lattice, consisting of ideal chains whose range and number of nearest-neighbor contacts are fixed to given values. Our simulations suggest an interesting exact relation concerning the internal energy per monomer of the interacting self-avoiding walk at the θ point.

Role of the KCNJ Gene Variants in the Clinical Outcome of Type 1 Diabetes.

Diabetes is considered as a disease with a wide and continuous clinical spectrum, ranging from Type 1 (T1D) and Type 2 Diabetes (T2D) with complex multifactorial causes. In the last years, particular attention has been focused on the predictive value and therapeutic potential of single nucleotide polymorphisms (SNPs). SNPs can alter the seed-sequence in miRNA's loci and miRNA target sites causing changes in the structure and influencing the binding function. Only few studies have investigated the clinical influence of SNPs, in particular potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ) gene variants in T1D population. The aim of the study is to investigate the occurrence and the possible metabolic significance of KCNJ polymorphism in a group of pediatric patients with T1D. The study was performed in a cohort of 90 Caucasian children and adolescents with T1D and 93 healthy subjects. Rs5210 polymorphism has been analyzed with a prevalence of the GG genotype in the patient group suggesting its association with T1D. Therefore, a relationship was found between GG genotype and body mass index (BMI) at diagnosis and insulin requirement (IR) after 6 months. The study suggested an action for rs5210 in determining the metabolic features of T1D pediatric patients, by showing some clues of insulin resistance in patients carrying that polymorphism.

Glutathione Blood Concentrations: A Biomarker of Oxidative Damage Protection during Cardiopulmonary Bypass in Children.

BACKGROUND: Pediatric open-heart surgery with cardiopulmonary bypass (CPB) still remains a risky interventional procedure at high mortality/morbidity. To date, there are no clinical, laboratory, and/or monitoring parameters providing useful information on perioperative stress. We therefore investigated whether blood concentrations of glutathione (GSH), a powerful endogenous antioxidant, changed in the perioperative period. METHODS: We conducted an observational study in 35 congenital heart disease (CHD) children in whom perioperative standard laboratory and monitoring parameters and GSH blood levels were assessed at five monitoring time points. RESULTS: GSH showed a pattern characterized by a progressive increase from pre-surgery up to 24 h after surgery, reaching its highest peak at the end of CPB. GSH measured at the end of CPB correlated with CPB duration, cross-clamping, arterial oxygen partial pressure, and with body core temperature. CONCLUSIONS: The increase in GSH levels in the perioperative period suggests a compensatory mechanism to oxidative damage during surgical procedure. Caution is needed in controlling different CPB phases, especially systemic reoxygenation in a population that is per se more prone to oxidative stress/damage. The findings may point the way to detecting the optimal temperature and oxygenation target by biomarker monitoring.

Osteopathic Manipulation Treatment Improves Cerebro-splanchnic Oximetry in Late Preterm Infants.

Background: To evaluate the effectiveness/side-effects of osteopathic manipulation treatment (OMT) performed on the 7th post-natal day, on cerebro-splanchnic oximetry, tissue activation and hemodynamic redistribution in late preterm (LP) infants by using near infrared spectroscopy (NIRS). Methods: Observational pretest-test study consisting in a cohort of 18 LPs who received OMT on the 7th post-natal day. NIRS monitoring was performed at three different time-points: 30 min before (T0), (30 min during (T1) and 30 min after OMT (T2). We evaluated the effects of OMT on the following NIRS parameters: cerebral (c), splanchnic (s) regional oximetry (rSO2), cerebro-splanchnic fractional tissue oxygen extraction (FTOE) and hemodynamic redistribution (CSOR). Results: crSO2 and cFTOE significantly (P < 0.001) improved at T0-T2; srSO2 significantly (P < 0.001) decreased and sFTOE increased at T0-T1. Furthermore, srSO2 and sFTOE significantly improved at T1-T2. Finally, CSOR significantly (P < 0.05) increased at T0-T2. Conclusions: The present data show that OMT enhances cerebro-splanchnic oximetry, tissue activation and hemodynamic redistribution in the absence of any adverse clinical or laboratory pattern. The results indicate the usefulness of further randomized studies in wider populations comparing the effectiveness of OMT with standard rehabilitation programs.

Effects of Sustained Inflation or Positive Pressure Ventilation on the Release of Adrenomedullin in Preterm Infants with Respiratory Failure at Birth.

OBJECTIVE: Delivery room (DR) management may play an important role in the development and prevention of lung injury. Therefore, in a cohort of low birth weight infants (LBW), we investigated the effects of two different lung recruitment maneuvers, such as positive pressure ventilation (PPV) and sustained inflation (SI) on adrenomedullin (AM), a well-established lung-specific vasoactive agent. STUDY DESIGN: This is a prospective case-control randomized study in 44 LBW infants spontaneously breathing with respiratory failure at birth requiring respiratory support. LBW were randomized to receive PPV (n = 22) or SI (n = 22) support. AM was measured from blood in samples collected at birth from arterial artery (BLT0) and at 1-hour (BLT1) and at 24-hour (BLT2) from peripheral venous site. AM assessment in urine samples was performed at 1-hour (URT1) and at 24-hour (URT2). RESULTS: No significant differences in AM (p > 0.05) blood (T0-T2) and urine (T1, T2) levels were observed between groups. CONCLUSION: The present data, showing the absence of any differences in AM blood and urine levels, suggest that PPV and SI are both feasible and equally effective DR maneuvers. The findings open the way to further studies evaluating the effects of PPV and SI on short-/long-term respiratory outcome through biomarkers assessment.

The Ca2+-Binding S100B Protein: An Important Diagnostic and Prognostic Neurobiomarker in Pediatric Laboratory Medicine.

In recent decades a significant scientific effort has focused on projects regarding the use of neurobiomarkers in perinatal medicine with a view to understanding the mechanisms that interfere with physiological patterns of brain development and lead to ominous effects in several human diseases. Numerous potential neurobiomarkers have been proposed for use in monitoring high-risk fetuses and newborns, including markers of oxidative stress, neuroproteins, and vasoactive agents. Nonetheless, the use of these markers in clinical practice remains a matter of debate. Recently, the calcium-binding S100B protein has been proposed as being an ideal neurobiomarker, thanks to its simple availability and easy reproducibility, to the possibility of detecting it noninvasively in biological fluids with good reproducibility, and to the possibility of a longitudinal evaluation in relation to reference curves. The present chapter contains an overview of the most significant studies on the assessment of S100B in different biological fluids as a trophic factor and/or marker of brain damage in high-risk fetuses and newborns.

C1858T Polymorphism of Protein Tyrosine Phosphatase Non-receptor Type 22 (PTPN22): an eligible target for prevention of type 1 diabetes?

INTRODUCTION: In type 1 diabetes (T1D), several genetic factors are associated to ß-cell autoimmunity onset and clinical progression. HLA-genes play a major role in susceptibility and initiation of ß-cell autoimmunity, whereas non-HLA genes may influence the destruction rate. Areas covered: Our review focuses on the possible role of the PTPN22 C1858 T variant as a prognostic factor, given its influence on disease variability. Moreover, we present the potential role of C1858 T as a target for tertiary prevention trials and new therapeutic strategies, such as the LYP inhibitors. We used PubMed for literature research; key words were 'PTPN22', 'C1858 T polymorphism', 'lymphoid-specific tyrosine phosphatase' and 'type 1 diabetes'. We selected publications between 2000 and 2016. Expert commentary: Current data suggest that PTPN22 can be a promising target for therapeutic interventions and identification of at-risk subjects in autoimmune diseases such as T1D.

Pyomyositis is not only a tropical pathology: a case series.

BACKGROUND: Pyomyositis is an acute bacterial infection of skeletal muscle that results in localized abscess formation. This infection was thought to be endemic to tropical countries, and is also known as "tropical pyomyositis". However, pyomyositis is increasingly recognized in temperate climates and is frequently associated with an immunosuppressive condition, such as human immunodeficiency virus, malignancy, and diabetes mellitus. It is also found in healthy and athletic people after strenuous or vigorous exercise or following localized and possibly unnoticed trauma. It can be primary or secondary to neighboring or remote infection. Primary pyomyositis is a rare condition that can affect children and adolescents. Diagnosis can be delayed because the affected muscle is deeply situated and local signs are not apparent. This delay in diagnosis can result in increased morbidity and a significant mortality rate. The pediatric population, which comprises 35% of the reported pyomyositis cases, is an especially difficult subset of patients to diagnose. CASE PRESENTATION: In our series, we describe the cases of four previously healthy Caucasian children who were admitted to our Pediatric Department with different clinical presentations. Pyomyositis in our patients was related to factors affecting the muscle itself, including strenuous exercise and direct muscle trauma. Therapy was started with a cephalosporin antibiotic and teicoplanin was subsequently added. The minimum length of therapy was 3 weeks. CONCLUSIONS: The diagnosis of pyomyositis in our patients, none of whom were immune-compromised, is confirmation that this disease is not an exclusive pathology of tropical countries and demonstrates that there is an increasing prevalence of pyomyositis in temperate climates.

Role of nutrition in preventing insulin resistance in children.

Nutrition during prenatal, early postnatal and pubertal period is crucial for the development of insulin resistance and its consequences. During prenatal period fetal environment and nutrition seems to interfere with metabolism programming later in life. The type of dietary carbohydrates, glycemic index, protein, fat and micronutrient content in maternal nutrition could influence insulin sensitivity in the newborn. The effects of lactation on metabolism and nutritional behavior later in life have been studied. Dietary habits and quality of diet during puberty could prevent the onset of a pathological insulin resistance through an adequate distribution of macro- and micronutrients, a diet rich in fibers and vegetables and poor in saturated fats, proteins and sugars. We want to overview the latest evidences on the risk of insulin resistance later in life due to both nutritional behaviors and components during the aforementioned periods of life, following a chronological outline from fetal development to adolescence.

Escherichia coli Urinary Infection as a Cause of Acute Hemorrhagic Edema in Infancy.

Acute hemorrhagic edema of infancy (AHEI) is a benign leukocytoclastic small-vessel vasculitis that affects infants, presenting with a classic clinical triad. Because of the self-limited progression, conservative management is the most common approach. We describe a case of AHEI apparently triggered by an Escherichia coli urinary tract infection.

The effect of obesity and type 1 diabetes on renal function in children and adolescents.

BACKGROUND: Early signs of renal complications can be common in youths with type 1 diabetes (T1D). Recently, there has been an increasing interest in potential renal complications associated with obesity, paralleling the epidemics of this condition, although there are limited data in children. HYPOTHESIS: Obese children and adolescents present signs of early alterations in renal function similar to non-obese peers with T1D. SUBJECTS: Eighty-three obese (age: 11.6 ± 3.0 yr), 164 non-obese T1D (age: 12.4 ± 3.2 yr), and 71 non-obese control (age: 12.3 ± 3.2 yr) children and adolescents were enrolled in the study. METHODS: Anthropometric parameters and blood pressure were measured. Renal function was assessed by albumin excretion rate (AER), serum cystatin C, creatinine and estimated glomerular filtration rate (e-GFR), calculated using the Bouvet's formula. RESULTS: Obese and non-obese T1D youths had similar AER [8.9(5.9-10.8) vs. 8.7(5.9-13.1) µg/min] and e-GFR levels (114.8 ± 19.6 vs. 113.4 ± 19.1 mL/min), which were higher than in controls [AER: 8.1(5.9-8.7) µg/min, e-GFR: 104.7 ± 18.9 mL/min]. Prevalence of microalbuminuria and hyperfiltration was similar between obese and T1D youths and higher than their control peers (6.0 vs. 8.0 vs. 0%, p = 0.02; 15.9 vs. 15.9 vs. 4.3%, p = 0.03, respectively). Body mass index (BMI) z-score was independently related to e-GFR (r = 0.328; p < 0.001), and AER (r = 0.138; p = 0.017). Hemoglobin A1c (HbA1c) correlated with AER (r = 0.148; p = 0.007) but not with eGFR (r = 0.041; p = 0.310). CONCLUSIONS: Obese children and adolescents show early alterations in renal function, compared to normal weight peers, and they have similar renal profiles than age-matched peers with T1D.

Ideal chains with fixed self-intersection rate.

We consider ideal chains in a hypercubic lattice Z(d), d≥3, with a fixed ratio m of self-intersection per monomer. Despite the simplicity of the geometrical constraint, this model shows some interesting properties, such as a collapse transition for a critical value m(c). Numerical simulations show a self-avoiding-walk-like behavior for mm(c). The collapse seems to show the same characteristics as the canonical thermodynamical models for the coil-globule transition.