The Effects of Uniform and Nonuniform Magnetic Fields in Plant Growth: A Meta-Analysis Approach.

Magnetic field (MF) effects have been reported in plants' growth, seed germination, gene expression, and water consumption. Accordingly, magnetic treatments have been proposed as a sustainable alternative to improve yields. Nevertheless, a comprehensive quantitative assessment is needed to understand whether their effects are general, species-specific, or dependent on the experimental setting. We conducted a multilevel meta-analysis of 45 articles that studied 29 different plant species. A positive and neutral effect of a nonuniform MF was found on fresh weight and germination rate, respectively. A significant association was found between a uniform MF and germination. These results suggest that MFs improve plant growth. However, the effects are highly dependent on the experimental setting. This opens exciting questions about the biophysical mechanisms underlying the perception and transduction of this environmental cue and about the possible translation to agricultural practices. © 2023 Bioelectromagnetics Society.

Intrinsic chiral field as vector potential of the magnetic current in the zig-zag lattice of magnetic dipoles.

Chiral magnetic insulators manifest novel phases of matter where the sense of rotation of the magnetization is associated with exotic transport phenomena. Effective control of such phases and their dynamical evolution points to the search and study of chiral fields like the Dzyaloshinskii-Moriya interaction. Here we combine experiments, numerics, and theory to study a zig-zag dipolar lattice as a model of an interface between magnetic in-plane layers with a perpendicular magnetization. The zig-zag lattice comprises two parallel sublattices of dipoles with perpendicular easy plane of rotation. The dipolar energy of the system is exactly separable into a sum of symmetric and antisymmetric long-range exchange interactions between dipoles, where the antisymmetric coupling generates a nonlocal Dzyaloshinskii-Moriya field which stabilizes winding textures with the form of chiral solitons. The Dzyaloshinskii-Moriya interaction acts as a vector potential or gauge field of the magnetic current and gives rise to emergent magnetic and electric fields that allow the manifestation of the magnetoelectric effect in the system.

Predicting the Risk of Mortality in Children using a Fuzzy-Probabilistic Hybrid Model.

Introduction: The mortality risk in children admitted to Pediatric Intensive Care Units (PICU) is usually estimated by means of validated scales, which only include objective data among their items. Human perceptions may also add relevant information to prognosticate the risk of death, and the tool to use this subjective data is fuzzy logic. The objective of our study was to develop a mathematical model to predict mortality risk based on the subjective perception of PICU staff and to evaluate its accuracy compared to validated scales. Methods: A prospective observational study in two PICUs (one in Spain and another in Latvia) was performed. Children were consecutively included regardless of the cause of admission along a two-year period. A fuzzy set program was developed for the PICU staff to record the subjective assessment of the patients' mortality risk expressed through a short range and a long range, both between 0% and 100%. Pediatric Index of Mortality 2 (PIM2) and Therapeutic Intervention Scoring System 28 (TISS28) were also prospectively calculated for each patient. Subjective and objective predictions were compared using the logistic regression analysis. To assess the prognostication ability of the models a stratified B-random K-fold cross-validation was performed. Results: Five hundred ninety-nine patients were included, 308 in Spain (293 survivors, 15 nonsurvivors) and 291 in Latvia (282 survivors, 9 nonsurvivors). The best logistic classification model for subjective information was the one based on MID (midpoint of the short range), whereas objective information was the one based on PIM2. Mortality estimation performance was 86.3% for PIM2, 92.6% for MID, and the combination of MID and PIM2 reached 96.4%. Conclusions: Subjective assessment was as useful as validated scales to estimate the risk of mortality. A hybrid model including fuzzy information and probabilistic scales (PIM2) seems to increase the accuracy of prognosticating mortality in PICU.

Magnetoelectric Effect in Dipolar Clusters.

We combine the anisotropy of magnetic interactions and the point symmetry of finite solids in the study of dipolar clusters as new basic units for multiferroics metamaterials. The Hamiltonian of magnetic dipoles with an easy axis at the vertices of polygons and polyhedra, maps exactly into a Hamiltonian with symmetric and antisymmetric exchange couplings. The last one gives rise to a Dzyaloshinskii-Moriya contribution responsible for the magnetic modes of the systems and their symmetry groups, which coincide with those of a particle in a crystal field with spin-orbit interaction. We find that the clusters carry spin current and that they manifest the magnetoelectric effect. We expect our results to pave the way for the rational design of magnetoelectric devices at room temperature.

[Validation of a Therapeutic Intervention Scoring System (TISS-28) in critically ill children]. / Validación de la escala simplificada de puntuación de intervenciones terapéuticas (TISS-28) en niños críticamente enfermos.

INTRODUCTION: There are numerous scales in intensive care units that are used to quantify the severity of patients. Most of them are very useful, although sometimes laborious to complete, thus limiting their use in usual practice. One of these scales, the Therapeutic Intervention Scoring System (TISS 76), has been validated in adult and paediatric units. Its simplified and updated version, the Simplified Therapeutic Intervention Scoring System (TISS 28), has not yet been validated in paediatric units. The aim of this study is to validate TISS 28, in order to have a simple and rapid scale. MATERIAL AND METHOD: A prospective non-interventional observational study was conducted in a Paediatric Intensive Care Unit (PICU) of a university hospital. Data were collected from 935 consecutive patients admitted to the PICU over a 3-year period. These included the values of TISS 76 and TISS 28 during the first 4days of admission and the subsequent outcome of the patients. RESULTS: The mean values of TISS 76 and TISS 28 for the first day of admission were 18.27 and 18.02, respectively. Values were higher in patients who had sequelae or died (17.58 versus 27.23 and 37.44, respectively for TISS 76 (P<.01); and 17.51 versus 23.80 and 33.44, respectively for TISS 28 (P<.01). A very good correlation was found between TISS 76 and TISS 28, with Pearson correlation and intraclass correlation coefficients> 0.9 (except for the 2nd day). The correlation equation for the overall 4 days was: TISS76=- 1.74+1.05×TISS28. TISS 28 was able to explain 82.4% of variability of TISS 76. The area under the curve with a confidence interval (CI) of 95% for the first day was 0.80 (0.73-0.87) for TISS 76, and 0.76 (0.67-0.84) for TISS 28. CONCLUSIONS: On observing the results obtained, TISS 28 can replace TISS 26 in our PICU, without worsening the information provided. Being a reliable scale and easier to apply, its practical application could be useful.

Designing Hysteresis with Dipolar Chains.

Materials that have hysteretic response to an external field are essential in modern information storage and processing technologies. A myriad of magnetization curves of several natural and artificial materials have previously been measured and each has found a particular mechanism that accounts for it. However, a phenomenological model that captures all the hysteresis loops and at the same time provides a simple way to design the magnetic response of a material while remaining minimal is missing. Here, we propose and experimentally demonstrate an elementary method to engineer hysteresis loops in metamaterials built out of dipolar chains. We show that by tuning the interactions of the system and its geometry we can shape the hysteresis loop which allows for the design of the softness of a magnetic material at will. Additionally, this mechanism allows for the control of the number of loops aimed to realize multiple-valued logic technologies. Our findings pave the way for the rational design of hysteretical responses in a variety of physical systems such as dipolar cold atoms, ferroelectrics, or artificial magnetic lattices, among others.

Helmet Versus Nasal-Prong CPAP in Infants With Acute Bronchiolitis.

BACKGROUND: Nasal prongs are frequently used to deliver noninvasive CPAP in bronchiolitis, especially in the youngest children. A helmet interface is an alternative that might be comparable to nasal prongs. We sought to compare these interfaces. METHODS: We performed a prospective, randomized, crossover, single-center study in an 8-bed multidisciplinary pediatric ICU in a university hospital. Infants age <3 months who were consecutively admitted to the pediatric ICU during a bronchiolitis epidemic season and fulfilled inclusion criteria were recruited. Subjects were randomly allocated to receive CPAP via a helmet or nasal prongs for 60 min. The subjects were then placed on the other CPAP system for another 60-min period (helmet then nasal prongs [H-NP] or nasal prongs then helmet [NP-H]). Measurements were taken at 30, 60, 90, and 120 min. Failure was defined as the need for further respiratory support. RESULTS: Sixteen subjects were included, with 9 in the H-NP group and 7 in the NP-H group. CPAP significantly reduced respiratory distress, showing no differences between the H-NP and NP-H groups in terms of improving the Modified Wood's Clinical Asthma Score from 4.8 ± 1 to 3 ± 0.9 and 2.7 ± 1.7 points at 60 min and 120 min in the H-NP group, respectively, and from 4.2 ± 0.9 to 2.8 ± 0.9 and to 2.9 ± 0.9 at 60 min and 120 min, respectively, in the NP-H group. Sedatives were used in only 3 subjects (2 in the NP-H group, P = .77). The failure rate was similar in both groups (3 of 9 subjects vs 3 of 7 subjects, P = .70). No significant differences were seen for heart rate, breathing frequency, FIO2 , or transcutaneous oxygen saturation response. CONCLUSIONS: Our results suggest that CPAP delivered by nasal prongs and CPAP delivered by helmet are similar in terms of efficacy in young infants with acute bronchiolitis.

Oscillation of the velvet worm slime jet by passive hydrodynamic instability.

The rapid squirt of a proteinaceous slime jet endows velvet worms (Onychophora) with a unique mechanism for defence from predators and for capturing prey by entangling them in a disordered web that immobilizes their target. However, to date, neither qualitative nor quantitative descriptions have been provided for this unique adaptation. Here we investigate the fast oscillatory motion of the oral papillae and the exiting liquid jet that oscillates with frequencies f~30-60 Hz. Using anatomical images, high-speed videography, theoretical analysis and a physical simulacrum, we show that this fast oscillatory motion is the result of an elastohydrodynamic instability driven by the interplay between the elasticity of oral papillae and the fast unsteady flow during squirting. Our results demonstrate how passive strategies can be cleverly harnessed by organisms, while suggesting future oscillating microfluidic devices, as well as novel ways for micro and nanofibre production using bioinspired strategies.

Costal mesenchymal chondrosarcoma with diffuse pleural and pericardial explantation in a pygmy goat.

A 3 year old intact male pygmy goat developed progressive weakness and eventual recumbancy over the course of 1 week, while maintaining its ability to eat and drink. The animal died and at necropsy, the parietal pleural surfaces and the pericardial surface were noted to be covered with firm, white, variably sized nodules that often formed linear arrays or coalesced into larger clumped aggregates. The visceral pleural surfaces of the ventral lung lobes were also covered with similar nodules. Histopathological and immunohistochemical evaluation of the submitted tissues revealed a diagnosis of mesenchymal chondrosarcoma with extensive seeding throughout the thoracic cavity.

Pro-adrenomedullin, pro-endothelin-1, procalcitonin, C-reactive protein and mortality risk in critically ill children: a prospective study.

INTRODUCTION: We tested the hypothesis that higher mid-regional pro-adrenomedullin (MR-proADM), carboxy-terminal pro-endothelin-1 (CT-proET-1), procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations would be associated with increased prediction of mortality risk scores. METHODS: Prospective observational study set in two pediatric intensive care units (PICUs). Two-hundred-thirty-eight patients were included. MR-proADM, CT-proET-1, PCT and CRP levels were compared between children with PRISM III and PIM 2 > p75 (Group A; n = 33) and the rest (Group B; n = 205). RESULTS: Median (range) MR-proADM levels were 1.39 nmol/L (0.52-12.67) in group A versus 0.54 (0.15-3.85) in group B (P < 0.001). CT-proET-1 levels were 172 pmol/L (27-500) versus 58 (4-447) (P < 0.001). PCT levels were 7.77 ng/mL (0.34-552.00) versus 0.28 (0.02-107.00) (P < 0.001). CRP levels were 6.23 mg/dL (0.08-28.25) versus 1.30 mg/dL (0.00-42.09) (P = 0.210). The area under the ROC curve (AUC) for the differentiation of group A and B was 0.87 (95% CI:0.81-0.821) for MR-proADM, 0.86 (95% CI:0.79-0.92) for CT-proET-1 and 0.84 (95% CI:0.74-0.94) for PCT. A MR-proADM > 0.79 nmol/L had 93% sensitivity and 76% specificity to differentiate groups, whereas a CT-proET-1 > 123 pmol/L had 77% sensitivity and 84% specificity, and a PCT concentration > 2.05 ng/mL had 80% sensitivity and specificity. CONCLUSIONS: In critically ill children, high levels of MR-proADM, CT-proET-1 and PCT were associated with increased prediction of mortality risk scores. MR-proADM, CT-proET-1 and PCT concentrations higher than 0.80 nmol/L, 123 pmol/L and 2 ng/mL, respectively, could be used by clinicians to identify critically ill children at higher prediction of risk death scores.

Correlation of oxygen saturation as measured by pulse oximetry/fraction of inspired oxygen ratio with Pao2/fraction of inspired oxygen ratio in a heterogeneous sample of critically ill children.

PURPOSE: Oxygen saturation as measured by pulse oximetry (Spo2)/fraction of inspired oxygen (Fio2) (SF) ratio has demonstrated to be an adequate marker for lung disease severity in children under mechanical ventilation. We sought to validate the utility of SF ratio in a population of critically ill children under mechanical ventilation, noninvasive ventilation support, and breathing spontaneously. MATERIALS AND METHODS: A retrospective database study was conducted in a pediatric intensive care unit of a university hospital. Children with Spo2 less than or equal to 97% and an indwelling arterial catheter were included. Simultaneous blood gas and pulse oximetry were collected in a database. Derivation and validation data sets were generated, and a linear mixed modeling was used to derive predictive equations. Model performance and fit were evaluated using the validation data set. RESULTS: Three thousand two hundred forty-eight blood gas and Spo2 values from 298 patients were included. 1/SF ratio had a strong linear association with 1/Pao2/Fio2 (PF) ratio in both derivation and validation data sets, given by the equation 1/SF = 0.00164 + 0.521/PF (derivation). Oxygen saturation as measured by pulse oximetry/Fio2 values for PF criteria of 100, 200, and 300 were 146 (95% confidence interval [CI], 142-150), 236 (95% CI, 228-244), and 296 (95% CI, 285-308). Areas under receiver operating characteristic curves for diagnosis of PF ratio less than 100, 200, and 300 with the SF ratio were 0.978, 0.952, and 0.951, respectively, in the validation data set. CONCLUSIONS: Oxygen saturation as measured by pulse oximetry/Fio2 ratio is an adequate noninvasive surrogate marker for PF ratio. Oxygen saturation as measured by pulse oximetry/Fio2 ratio may be an ideal noninvasive marker for patients with acute hypoxemic respiratory failure.

Macroscopic magnetic frustration.

Although geometrical frustration transcends scale, it has primarily been evoked in the micro- and mesoscopic realm to characterize such phases as spin ice, liquids, and glasses and to explain the behavior of such materials as multiferroics, high-temperature superconductors, colloids, and copolymers. Here we introduce a system of macroscopic ferromagnetic rotors arranged in a planar lattice capable of out-of-plane movement that exhibit the characteristic honeycomb spin ice rules studied and seen so far only in its mesoscopic manifestation. We find that a polarized initial state of this system settles into the honeycomb spin ice phase with relaxation on multiple time scales. We explain this relaxation process using a minimal classical mechanical model that includes Coulombic interactions between magnetic charges located at the ends of the magnets and viscous dissipation at the hinges. Our study shows how macroscopic frustration arises in a purely classical setting that is amenable to experiment, easy manipulation, theory, and computation, and shows phenomena that are not visible in their microscopic counterparts.

Mechanical response of a self-avoiding membrane: fold collisions and the birth of conical singularities.

An elastic membrane that is forced to reside in a container smaller than its natural size will deform and upon further volume reduction eventually crumple. The crumpled state is characterized by the localization of energy in a complex network of highly deformed crescent-like regions joined by line ridges. In this article we study through a combination of experiments, numerical simulations, and analytic approaches the emergence of localized regions of high stretching when a self-avoiding membrane is subject to a severe geometrical constraint. Based on our experimental observations and numerical results we suggest that at moderate packing fraction interlayer interactions produce a response equivalent to that of a thicker membrane that has the shape of the deformed one. We find that new conical dislocations, coined satellite d-cones, appear as the deformed membrane further compactifies. When these satellite d-cones are born, a substantial relaxation of the mechanical response of the membrane is observed. Evidence is found that friction plays a key role in stabilizing the folded structures.

Non-invasive ventilation in pediatric status asthmaticus: a prospective observational study.

OBJECTIVE: Non-invasive ventilation (NIV) has been shown to be effective in different causes of respiratory failure in both adult and pediatric patients. However, its role in status asthmaticus (SA) remains unclear. We designed a prospective study to assess the feasibility of NIV in children with SA. STUDY DESIGN: Prospective observational study, over a 4.5-year period. PATIENT SELECTION: Children with SA unresponsive to conventional therapy with a modified Wood's clinical asthma score (m-WCAS) ≥4 and marked increased work of breathing, were included. METHODOLOGY: Patients were placed on pressure support NIV. During NIV therapy, salbutamol was nebulized continuously and ipratropium bromide every 2 hr; methyl-prednisolone was given at a dose of 1-2 mg/kg/6 hr. Clinical variables were measured at baseline and at 1, 6, 12, 24, and 48 hr. RESULTS: During the study period, there were 122 PICU admissions due to SA; 72 episodes fulfilled inclusion criteria. Baseline mean values were as follows: m-WCAS of 5.7 points, heart rate (HR) of 166.7 beats/min, respiratory rate (RR) of 49.5 breaths/min and FiO(2) of 45.3%. In the first hour m-WCAS fell 2.3 ± 1.5 points, HR 13.5 ± 14 beats/min, and RR 9.8 ± 10 breaths/min (P < 0.01). After institution of NIV therapy, 5 children required intubation due to increasing respiratory distress. There was one case of massive subcutaneous emphysema, with no other serious adverse effects associated with NIV. CONCLUSIONS: These results show that NIV is a feasible therapy in children with SA unresponsive to conventional treatment. Pediatr. Pulmonol. 2011; 46:949-955. © 2011 Wiley-Liss, Inc.

Intervention to reduce catheter-related bloodstream infections in a pediatric intensive care unit.

OBJECTIVE: Identification of catheter-related bloodstream infection (CR-BSI) risk factors and determination of whether intervention related to identified risk factors would reduce CR-BSI rates. DESIGN: Prospective, observational, interventional and interrupted time-series study. SETTING: Pediatric Intensive Care Unit (PICU) in a university hospital. METHODS: During a 7-year period, 609 central venous catheters (CVC) were placed in 389 patients. CR-BSI risk factors were determined by multivariate analysis during two periods (January 2000-November 2002 and January 2003-April 2007). An intervention to reduce identified risk factors was performed after the first period. CR-BSI rates per 1,000 catheters-days were compared during the two periods. RESULTS: The CR-BSI rate was 11.94 [(95% CI 7.94-15.94)/1,000 catheter-days during the first period]. Weight [OR 0.96 (0.91-0.99)], parenteral nutrition (PN) [OR 3.38 (1.40-8.19)] and indwelling time (IT) [OR 1.08 (1.02-1.14)] were CR-BSI risk factors. Practice changes aimed at reducing PN and IT were introduced. PN decreased from 49.8% [95% CI (49.7-49.9)] to 26.7% [(95% CI 26.6-26.8)] (p < 0.001), and IT dropped from 9.92 (95% CI 9.09-10.75) to 8.13 (95% CI 7.47-8.79) days (p < 0.001). The CR-BSI rate was reduced to 3.05 (95% CI 0.93-5.17)/1,000 catheter-days. During the last period, PN and IT were no longer CR-BSI risk factors. Type of catheterisation (guide wire exchange) [OR 6.66 (1.40-31.7)] was the only CR-BSI risk factor. CONCLUSIONS: PN and IT were independent CR-BSI risk factors during the first period. An intervention focused on PN and IT reduction resulted in a sustained decrease of CR-BSI rates in our PICU.

Non invasive ventilation after extubation in paediatric patients: a preliminary study.

BACKGROUND: Non-invasive ventilation (NIV) may be useful after extubation in children. Our objective was to determine postextubation NIV characteristics and to identify risk factors of postextubation NIV failure. METHODS: A prospective observational study was conducted in an 8-bed pediatric intensive care unit (PICU). Following PICU protocol, NIV was applied to patients who had been mechanically ventilated for over 12 hours considered at high-risk of extubation failure -elective NIV (eNIV), immediately after extubation- or those who developed respiratory failure within 48 hours after extubation -rescue NIV (rNIV)-. Patients were categorized in subgroups according to their main underlying conditions. NIV was deemed successful when reintubation was avoided. Logistic regression analysis was performed in order to identify predictors of NIV failure. RESULTS: There were 41 episodes (rNIV in 20 episodes). Success rate was 50% in rNIV and 81% in eNIV (p = 0.037). We found significant differences in univariate analysis between success and failure groups in respiratory rate (RR) decrease at 6 hours, FiO2 at 1 hour and PO2/FiO2 ratio at 6 hours. Neurologic condition was found to be associated with NIV failure. Multiple logistic regression analysis identified no variable as independent NIV outcome predictor. CONCLUSIONS: Our data suggest that postextubation NIV seems to be useful in avoiding reintubation in high-risk children when applied immediately after extubation. NIV was more likely to fail when ARF has already developed (rNIV), when RR at 6 hours did not decrease and if oxygen requirements increased. Neurologic patients seem to be at higher risk of reintubation despite NIV use.

Iatrogenic tension pneumothorax in children: two case reports.

INTRODUCTION: Two cases of iatrogenic tension pneumothorax in children are reported. CASE PRESENTATIONS: Case 1: A 2-year-old boy with suspected brain death after suffering multiple trauma suddenly developed intense cyanosis, extreme bradycardia and generalized subcutaneous emphysema during apnea testing. He received advanced cardiopulmonary resuscitation and urgent bilateral needle thoracostomy. Case 2: A diagnostic-therapeutic flexible bronchoscopy was conducted on a 17-month-old girl, under sedation-analgesia with midazolam and ketamine. She very suddenly developed bradycardia, generalized cyanosis and cervical, thoracic and abdominal subcutaneous emphysema. Urgent needle decompression of both hemithoraces was performed. CONCLUSION: In techniques where gas is introduced into a child's airway, it is vital to ensure its way out to avoid iatrogenic tension pneumothorax. Moreover, the equipment to perform an urgent needle thoracostomy should be readily available.

Mechanical complications during central venous cannulations in pediatric patients.

OBJECTIVE: Identification of early mechanical complications (EMC) of central venous catheterizations (CVC) in pediatric patients and determination of EMC risk factors. DESIGN: Prospective observational study. SETTING: Pediatric intensive-care unit in a university hospital. PATIENTS AND MEASUREMENTS: Eight-hundred and twenty-five CVC were performed in 546 patients. Age, weight, gender, mechanical ventilation, analgesia, resident CVC failure, CVC indication, admission diagnosis, emergency or scheduled procedure, type of catheter (diameter, lumen number), catheter final location, number of attempts, and EMC were recorded. Risk factors for EMC were determined by multivariate analysis. RESULTS: Median patient age was 22.0 months (0-216 months). CVC was an emergency procedure in 421 (51%) cases, scheduled in 336 (40.7%), and guide-wire exchanged in 68 (8.2%). There were 293 (35.5%) internal jugular, 116 (14.1%) subclavian, and 416 (50.4%) femoral catheters. CVC was performed by staff physicians in 35.8% cases, supervised residents in 43.4%, and staff after resident failure in 20.8%. 151 EMC occurred in 144 CVC (17.5%). The most common EMC were arterial puncture (n = 60; 7.2%), catheter malposition (n = 39; 4.7%), arrhythmias (n = 19; 2.3%), and hematoma (n = 12; 1.4%). Resident failure to perform CVC (OR 2.53; CI 95% 1.53-4.16), high venous access (subclavian or jugular) (OR 1.91; CI 95% 1.26-2.88), and number of attempts (OR 1.10; CI 95% 1.03-1.17) were independently associated with EMC. CONCLUSIONS: EMC of CVC were common in a teaching university hospital, but severe complications were very uncommon. Resident failure to perform CVC, high venous access, and number of attempts were independent risk factors for EMC of CVC.