Benefits of cascaded nonlinear dynamics in hybrid fibers for low-noise supercontinuum generation.

The recent development of fiber supercontinuum (SC) sources with ultra-low noise levels has been instrumental in advancing the state-of-the-art in a wide range of research topics. However, simultaneously satisfying the application demands of maximizing spectral bandwidth and minimizing noise is a major challenge that so far has been addressed with compromise, found by fine-tuning the characteristics of a single nonlinear fiber transforming the injected laser pulses into a broadband SC. In this work, we investigate a hybrid approach that splits the nonlinear dynamics into two discrete fibers optimized for nonlinear temporal compression and spectral broadening, respectively. This introduces new design degrees of freedom, making it possible to select the best fiber for each stage of the SC generation process. With experiments and simulations we study the benefits of this hybrid approach for three common and commercially available highly nonlinear fiber (HNLF) designs, focusing on flatness, bandwidth and relative intensity noise of the generated SC. In our results, hybrid all-normal dispersion (ANDi) HNLF stand out as they combine the broad spectral bandwidths associated with soliton dynamics with extremely low noise and smooth spectra known from normal dispersion nonlinearities. Hybrid ANDi HNLF are a simple and low-cost route for implementing ultra-low noise SC sources and scaling their repetition rate for various applications such as biophotonic imaging, coherent optical communications, or ultrafast photonics.

Does anticonvulsant treatment influence pain perception in epileptic children?

BACKGROUND: The aims of our study were to evaluate pain perception in epileptic children and to establish the influence of anticonvulsant drugs on pain perception. METHODS: The study involved 40 children, 30 with epilepsy and 10 healthy control subjects. In the group of epileptic children, 10 were not treated and 20 assumed a single drug. From all children of each group, one sample of saliva was collected through a noninvasive device 15 minutes before (t0), during (t1), and 15 minutes after (t2) blood withdrawal, and salivary α-amylase activity was then determined. RESULTS: No statistically significant difference was found at t0 and at t1, indicating that in both groups venipuncture equally induced a state of stress. Conversely, at t2 a statistically significant difference (p = 0.0195) was found, suggesting that epileptic children presented a greater sensitization to pain and a slower recovery from stress. Comparing furthermore data obtained in children with epilepsy not treated with those registered in treated ones, we found a statistically significant difference at t0 (p = 0.012), at t1 (p = 0.037), and at t2 (p = 0.011). CONCLUSIONS: Anticonvulsant drugs do not seem to influence pain perception and enzymatic activity levels in epileptic patients.

IL-1 ß and IL-6 upregulation in children with H1N1 influenza virus infection.

The role of cytokines in relation to clinical manifestations, disease severity, and outcome of children with H1N1 virus infection remains thus far unclear. The aim of this study was to evaluate interleukin IL-1 ß and IL-6 plasma expressions and their association with clinical findings, disease severity, and outcome of children with H1N1 infection. We prospectively evaluated 15 children with H1N1 virus infection and 15 controls with lower respiratory tract infections (LRTI). Interleukin plasma levels were measured using immunoenzymatic assays. Significantly higher levels of IL-1 ß and IL-6 were detected in all patients with H1N1 virus infection compared to controls. It is noteworthy to mention that in H1N1 patients with more severe clinical manifestations of disease IL-1 ß and IL-6 expressions were significantly upregulated compared to H1N1 patients with mild clinical manifestations. In particular, IL-6 was significantly correlated with specific clinical findings, such as severity of respiratory compromise and fever. No correlation was found between interleukin expression and final outcome. In conclusion, H1N1 virus infection induces an early and significant upregulation of both interleukins IL1 ß and IL-6 plasma expressions. The upregulation of these cytokines is likely to play a proinflammatory role in H1N1 virus infection and may contribute to airway inflammation and bronchial hyperreactivity in these patients.

Massive proteinuria: a possible side effect of pyrantel pamoate?

Drug-induced renal injury represents a frequent clinical entity. The most common drugs associated with acute tubular necrosis are aminoglycosides, amphotericin B, radiocontrast agents, and cyclosporine, but no data exist about the potential renal toxicity due to anthelmintics administration. Anthelmintics are commonly considered quite safe agents, and side effects such as gastrointestinal, neurologic, hematologic, or hepatic injury have been only rarely described. We report a 4-year-old boy with persistent massive proteinuria without any other symptoms/signs suggesting nephrotic syndrome (NS). The only relevant anamnestic data was the administration of pyrantel pamoate due to oxyuriasis 7 days before the proteinuria development. The patient was affected by NS diagnosed 6 months before and treated with a 12-week course of corticosteroids. During follow-up, carried out at 3 and 6 months after discharge, he did not show further episodes of proteinuria, and no clinical symptoms/signs suggesting a relapse of NS were ever detected. Considering that the proteinuria observed in our patient spontaneously disappeared after 10 days without any treatment, apart from the interruption of the anthelmintic therapy, we would like to alert pediatricians about the possible occurrence of anthelmintics-related renal complications especially among predisposed patients and to perform a watchful waiting not considering the presence of even massive proteinuria as a certain sign of NS relapse.

An Unusual Pneumoperitoneum in an Extremely Low Birth Weight Preterm Newborn.

Pneumoperitoneum (PP) is a radiological diagnosis, characterized by the presence of air under the diaphragm, that in 90% of cases results from a perforated viscus while in 10% of cases it is not associated to perforation, the so-called non-surgical or spontaneous PP. Spontaneous PP is rare at any paediatric and neonatal age. In the neonatal population, sporadic cases of spontaneous PP have been described, almost invariably following mechanical ventilation. We presented the case of an extremely low birth weight infant (ELBW) with spontaneous PP secondary to pneumomediastinum who has never underwent mechanical ventilation or cardiopulmonary resuscitation. (www.actabiomedica.it).

Neurodevelopmental outcomes in very preterm infants: The role of severity of Bronchopulmonary Dysplasia.

OBJECTIVE: Bronchopulmonary dysplasia is a chronic respiratory disease that still affects preterm neonates; its association with neurodevelopmental (ND) impairment is already known. Different studies investigated neurodevelopmental outcomes in infants with BPD, often using the old dichotomous definition (BPD vs Non-BPD). This retrospective study aims to evaluate the role of different BPD severity grades on ND outcomes at 24 months of corrected age (CA). METHODS: All preterm infants born between 2011 and 2015 in the study hospital with a gestational age (GA) ≤ 30 weeks and discharged from our NICU were included and were divided in infants with and without BPD. Infants with BPD were divided into three severity groups as defined by NICHD/NHLBI Workshop in 2001, and were compared to their Non-BPD peers, matching them according to the same GA and year of birth. At 24 months postmenstrual age, we assessed general outcomes (growth and hospital readmissions) and neurodevelopmental outcomes (motor, developmental and sensory outcomes) with a standardized assessment. RESULTS: We enrolled 89 patients affected by BPD of different grades of severity and a control group of 89 preterm infants without BPD. Infants with Moderate and Severe BPD showed a significantly higher corrected odds ratio (OR) for cognitive impairment compared to controls. Within the group of infants without severe disability (regarding Griffiths' scales), infants with Moderate and Severe BPD as well as infants with Mild BPD showed a significantly higher risk of a lower total Developmental Quotient (DQ) score, even after correction for confounding factors. CONCLUSIONS: Our study evidenced that not only Severe BPD infants, but also Moderate ones showed a higher risk of overall cognitive impairment at 24 months CA. Within the group of infants without severe disability, also those with Mild BPD had lower Griffiths DQ scores than those without. This would suggest that infants with BPD, regardless of severity, warrant neurodevelopmental follow-up.

Nonchemical-vapor-deposition process for fabrication of highly efficient Yb-doped large core fibers.

A new fabrication process of active optical silica glass based on direct sand vitrification is proposed. This method, an alternative to chemical vapor deposition (CVD), allows the fabrication of homogeneous and highly Yb(3+)-doped rods that are ten times larger in diameter than those produced by CVD. For large-mode-area fibers fabricated by the stack-and-draw method, this is a tremendous technical breakthrough that could offer great flexibility in fiber design. As a proof of concept, we focused here on the fabrication and characterization of active core material surrounded by pure silica. Consequently, we draw a simple multimode step-index fiber. The index ripple in the core that matches our objectives is approximately 2.2x10(-4). For this first demonstration, the core material is codoped with Yb(2)O(3) (3600 parts in 10(6)(ppm) by weight) and Al(2)O(3), yielding a 180 dB m(-1) absorption at a wavelength of 975 nm, whereas the background loss is around 0.8 dB m(-1). The continuous-wave laser obtained with this fiber exhibits 74% slope efficiency.

CIGS thin-film solar module processing: case of high-speed laser scribing.

In this paper, we investigate the laser processing of the CIGS thin-film solar cells in the case of the high-speed regime. The modern ultra-short pulsed laser was used exhibiting the pulse repetition rate of 1 MHz. Two main P3 scribing approaches were investigated - ablation of the full layer stack to expose the molybdenum back-contact, and removal of the front-contact only. The scribe quality was evaluated by SEM together with EDS spectrometer followed by electrical measurements. We also modelled the electrical behavior of a device at the mini-module scale taking into account the laser-induced damage. We demonstrated, that high-speed process at high laser pulse repetition rate induced thermal damage to the cell. However, the top-contact layer lift-off processing enabled us to reach 1.7 m/s scribing speed with a minimal device degradation. Also, we demonstrated the P3 processing in the ultra-high speed regime, where the scribing speed of 50 m/s was obtained. Finally, selected laser processes were tested in the case of mini-module scribing. Overall, we conclude, that the top-contact layer lift-off processing is the only reliable solution for high-speed P3 laser scribing, which can be implemented in the future terawatt-scale photovoltaic production facilities.

Self-compensating amplifier design for cw and Q-switched high-power Nd:YAG lasers.

We experimentally demonstrate a self-adaptive compensation of the pump power dependent thermal lens in an Nd:YAG laser through a thin layer of a medium with a negative temperature dependence of the refractive index. The layer is thermally coupled to the laser rod and leads to a strikingly improved beam quality over a large stability range. The scheme allows for a scaling to high powers as well as pulsed-mode operation.

Continuous glucose monitoring in preterm infants: evaluation by a modified Clarke error grid.

BACKGROUND: Continuous glucose monitoring using subcutaneous sensors has been validated in adults and children with diabetes, and was found to be useful in the management of glucose control. We aimed to assess feasibility and reliability of a new continuous glucose monitoring system (CGMS) in a population of preterm neonates using a Clarke error grid (CEG) specifically modified for preterm infants. METHODS: Preterm infants were recruited within 24 h from delivery. A subcutaneous sensor connected to a CGMS was inserted and maintained for 6 days. Data collected from CGMS were compared with data obtained using a glucometer. Management of the infants followed standard protocols and was not influenced by CGMS readings. RESULTS: Twenty patients (9 males) were included. Median (range) gestational age was 32 weeks (27-36) and median (range) birth weight was 1350 g (860-3360). Average CGMS recording time was 137 h, for a total of 449 paired glucose levels. CEG and modified CEG criteria for clinical significance were met. CONCLUSION: CGMS is a safe and clinically adequate method to estimate glucose levels in preterm infants. As the glucose level can be evaluated in real time, this CGMS could be useful to reduce the number of heel sticks, to observe glycaemic trends and to promptly detect episodes of both hypo- and hyper-glycaemia.

Combined Dietary Recommendations, Desmopressin, and Behavioral Interventions May Be Effective First-Line Treatment in Resolution of Enuresis.

PURPOSE: Nocturnal enuresis (NE) is a very common multifactorial pediatric disorder and in children with­out any other lower urinary tract symptoms is defined as monosymptomatic NE (MNE). Pharmacologi­cal, psychological/behavioral, and alternative interventions are commonly used and the first-line drug ther­apy for patients with MNE is desmopressin (dDAVP) but the response rate is less than 40-60% and the relapse rate is about 50-80% after treatment. Many studies show that some foods and beverages can promote diuresis or bladder irritability, which in some people can exacerbate bladder symptoms and NE. The pres­ent study aimed to compare the efficacy of combined specific dietary advices and dDAVP vs dDAVP alone. MATERIALS AND METHODS: We enrolled in the study 172 patients affected by MNE between January 2013 and May 2014, of these 35 were excluded. The inclusion criterion was primary MNE and exclusion criteria included non-MNE, secondary MNE and lactose intolerance. Children were treated with dDAVP at a dose of 120 µg a day and were randomized to receive dietary recommendations. They were asked to fill out a char­ter depicting their wet and dry nights for the period of treatment. Sixty-seven patients were randomly as­signed to receive dDAVP and dietary advices (group A) and 70 patients to receive dDAVP alone (group B). RESULTS: We included in our study 137 children, 102 (74.5%) male, and 35 (25.5%) female, aged be­tween 5 and 14 years. Our results show a higher response rate and a lower number of relapse in group A vs group B with 67.2% of responders in group A vs 58.6% in group B, after 3 months of ther­apy and 31.1% of relapse in group A vs 46.3% in group B one month, after the end of treatment. CONCLUSION: Our results show the effectiveness of specific dietary advices in the manage­ment of primary MNE. However further studies are needed to determine whether the differ­ence between therapy with combined dietary recommendations and dDAVP vs dDAVP alone.

Oral desmopressin lyophilisate (MELT) for monosymptomatic enuresis: structured versus abrupt withdrawal.

OBJECTIVE: To investigate whether a structured withdrawal program from a sublingual formulation of fast-melting oral desmopressin lyophilisate (MELT) is superior to a sudden withdrawal from this formulation in the treatment of monosymptomatic nocturnal enuresis. MATERIALS AND METHODS: One hundred and three children presented to our pediatric nephrology outpatient clinic for bedwetting. Eighty-one children, aged between 5½ and 14 years (mean age 8.64 years), were treated with MELT at a dosage of 120 mcg a day. Responders were randomized to been withdrawn from therapy, after 3 months, abruptly or in a structured withdrawal program (60 mcg/day for 15 days and then 60 mcg every second evening for another 15 days). Main outcome parameter was relapse rate 1 month after the end of treatment. Relapse was defined as bedwetting occurring more than 2 nights per month after the 1-month treatment-free period. RESULTS: Relapse rate at 1 month after the end of treatment was 47.83% in the group on a structured program versus 45.83% in the abrupt termination group (p = 0.89). CONCLUSION: Our study suggests that a structured withdrawal program from MELT therapy doesn't offer advantages compared to an abrupt termination in children with monosymptomatic nocturnal enuresis.

Can MII-pH values predict the duration of treatment for GERD in preterm infants?

BACKGROUND: Little is known regarding the prognostic role of Multichannel Intraluminal Impedance and pH monitoring (MII/pH) parameters in preterm infants with Gastro-Esophageal Reflux Disease (GERD). AIM: Our study aimed to evaluate the relationship between MII/pH variables and the duration of pharmacological therapy for GERD, in preterm infants with gestational age (GA) ≤34weeks. SUBJECTS, STUDY DESIGN, OUTCOME MEASURES: We retrospectively reviewed data of all newborns with GA ≤34weeks that underwent MII/pH in our Neonatal Intensive Care Unit (NICU) and pharmacological treatment for GERD. We included them in a 12-month follow-up program. MII/pH parameters were used as independent variables and the duration of pharmacological therapy as dependent variable in linear regression models. RESULTS: 16 patients (GA 28.4±1.8weeks, BW 1122±427g) were enrolled into the study. Regression analysis performed on all reflux events reported a significant correlation between the duration of pharmacological treatment and MII-BEI (r(2)=0.36, p=0.01) and MII-reflux frequency (r(2)=0.33, p=0.02). Moreover, regression analysis performed on all events classified according to the corresponding pH change - acidic (ac.), weakly acidic (w.ac.) or weakly alkaline (w.a.) - showed a significant correlation between the duration of pharmacological treatment and MII-w.ac.BEI (r(2)=0.26, p=0.05), MII-w.ac. reflux frequency (r(2)=0.44, p=0.01), and MII-proximal w.ac. reflux frequency (r(2)=0.35, p=0.02). No statistically significant correlation was found between pH-Reflux Index and the duration of treatment. CONCLUSION: The study shows how, in our population of preterm infants, MII-parameters could have not only a diagnostic role, but also a prognostic value in terms of the duration of pharmacological treatment.

Efficacy and Safety of Dimeticone in the Treatment of Lice Infestation through Prophylaxis of Classmates.

BACKGROUND: We conducted a study to evaluate efficacy and safety of dimeticone 4%, a lotion with no conventional insecticide activity, to cure lice infection and to prevent spread of infestation/reinfestation by prophylaxis of classmates. METHODS: The study is carried out between April 2008 and June 2008 in Petranova International Institute in Rome. A total of 131 children, aged 3 to 13 years (median age: 7 years) were included in the study. All participants received treatment with dimeticone 4% that was applied both to children with the infestation, to cure it, and to all classmates, to prevent the spreading of the infestation. They have been controlled after 7 and 30 days from the application of dimeticone. RESULTS: At baseline we found a positivity of lice infestation in 23/131 children (17.6%), whereas 108/131 (82.4%) children were free from lice. After 7 days of treatment with dimeticone 4%, 7/23 (30.4%) positive children still had lice infestation, with a cure rate of 69.6% (16/23). At 30 days 26/131 children (19.9%) were infested: 15 children were lice free at baseline whereas 11 had lice at both evaluations; the cure rate amounted to 52.2% (12/23). The reinfestation rate (percentage of positive children that showed negativity at baseline) was 5.3% (7/131) at 7 days and 11.5% (15/131) at 30 days. CONCLUSION: The lower reinfestation rate showed in our trial suggests that this approach could be effective in reducing spreading of head lice in small communities. More studies are needed to confirm our findings.

Polythelia: still a marker of urinary tract anomalies in children?

OBJECTIVE: Supernumerary nipples (SNN), or polythelia, are the most common form of the accessory mammary tissue malformation. The frequency of this condition ranges from 0.2% to 5.6% depending on various factors. This condition is associated with several anomalies, although this association is often controversial. The aim of this study was to evaluate the association between SNN and kidney/urinary tract (K/UT) anomalies, where anomalies is taken to mean functional disorders, malformations and diseases. MATERIAL AND METHODS: A case-control study was performed. The study evaluated 166 children (case group) referred to the Pediatric Nephrology Unit of the Department of Pediatrics of the Catholic University of Rome and 182 children (control group) admitted to the Department of Pediatrics because of pathologies not involving the urinary tract. RESULTS: There were 11 children with SNN in the case group, and only two patients in the control group (6.62% vs 1.09%, p<0.05). CONCLUSION: The results show a high incidence of K/UT anomalies in children with SNN, and therefore K/UT should be investigated in this specific population.

Superbroadband fluorescence fiber fabricated with granulated oxides.

We demonstrate a single-core multiply doped fiber that, when pumped with a single pump source of approximately 800 nm, emits a more than two-octaves-spanning fluorescence spectrum ranging from 365 to 2300 nm. The fiber preform is manufactured from granulated oxides, and the core is doped with five different rare earths. At a pump power of 250 mW the total emitted power is 34 microW; given a core diameter of 6.5 microm and a numerical aperture of 0.1, the radiance exceeds 3 kW sr(-1) cm(-2). We also demonstrate direct diode pumping of the fiber.

Broadband emission from a multicore fiber fabricated with granulated oxides.

We demonstrate a multicore multidopant fiber which, when pumped with a single pump source around approximately 800 nm, emits a more than one octave-spanning fluorescence spectrum ranging from 925 to 2300 nm. The fiber preform is manufactured from granulated oxides and the individual cores are doped with five different rare earths, i.e., Nd3+, Yb3+, Er3+, Ho3+, and Tm3+.