Editorial for the Special Issue on AC Electrokinetics in Microfluidic Devices, Volume II.

The use of AC electric fields in manipulating and characterizing liquids and suspended particles in microfluidic systems continues to drive innovation in several fields, such as colloidal science, microelectronics, and biotechnology [...

Zoonosis screening in Spanish immunocompromised children and their pets.

Introduction: Although pets provide several social-emotional benefits for children, the risk of zoonosis must be considered among immunocompromised individuals.

Methods: A prospective study was conducted in a tertiary hospital including immunocompromised patients younger than 20 years owning dogs and/or cats. Colonization and/or infection was evaluated by stool studies, bacterial swabs, blood polymerase chain reaction and serological studies in both patients and their pets, to evaluate potential zoonotic transmission occurrence.

Seizures in Children With Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

Background: Although respiratory symptoms are the most prominent manifestations of coronavirus disease 2019 (COVID-19), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and especially the omicron variant, may cause neurological manifestations such as seizures. It remains unclear if specific variants of the virus increase the risk of seizures more than others.

Material And Methods: This was a retrospective multicenter study of pediatric (zero to 16 years) patients with COVID-19 who attended five pediatric emergency departments in Madrid, Spain, between March 2020 and July 2022.

Induced-charge electrophoresis of a tilted metal nanowire near an insulating wall.

Electric fields are commonly used to control the orientation and motion of microscopic metal particles in aqueous suspensions. For example, metallodielectric Janus spheres are propelled by the induced-charge electro-osmotic flow occurring on their metallic side, the most common case in electrokinetics of exploiting symmetry breaking of surface properties for achieving net particle motion. In this work, we demonstrate that a homogeneous metal rod can translate parallel to a dielectric wall as a result of the hydrodynamic wall-particle interaction arising from the induced-charge electro-osmosis on the rod surface.

The influence of frequency and gravity on the orientation of active metallo-dielectric Janus particles translating under a uniform applied alternating-current electric field.

Theoretical and numerical models of active Janus particles commonly assume that the metallo-dielectric interface is parallel to the driving applied electric field. However, our experimental observations indicate that the equilibrium angle of orientation of electrokinetically driven Janus particles varies as a function of the frequency and voltage of the applied electric field. Here, we quantify the variation of the orientation with respect to the electric field and demonstrate that the equilibrium position represents the interplay between gravitational, electrostatic and electrohydrodynamic torques.

Concentration-polarization electroosmosis for particle fractionation.

Concentration-polarization electroosmosis (CPEO) refers to steady-state electroosmotic flows around charged dielectric micro-particles induced by low-frequency AC electric fields. Recently, these flows were shown to cause repulsion of colloidal particles from the wall of a microfluidic channel when an electric field is applied along the length of the channel. In this work, we exploit this mechanism to demonstrate fractionation of micron-sized polystyrene particles and bacteria in a flow-focusing device.

Retrospective study of acute mastoiditis in children in Spain attended in a Pediatric Emergency department.

Objective: To analyze the cases of acute mastoiditis, characteristics, management and complications in children attended in the emergency department.

Methods: Retrospective study of acute mastoiditis in a Spanish tertiary hospital over a 6-year period (2018-2023).

Results: One hundred two episodes of acute mastoiditis were analyzed (54% males, median age 1.

The role of veterinarians in zoonosis prevention: Advising families of immunocompromised children with pets.

Background: Pet ownership is widespread, offering numerous benefits to individuals and families. However, the risk of zoonotic diseases must be carefully considered, especially for immunosuppressed patients. Knowledge gaps in preventive measures for zoonoses have been identified, underscoring the vital role of veterinarians in addressing this issue.

Hyponatremia and other potential markers of ultrasound abnormalities after a first febrile urinary tract infection in children.

Unlabelled: Urinary tract infections are the initial manifestation in 30% of urinary tract malformations. Identifying these patients, who could benefit from a specific treatment, is still challenging. Hyponatremia during urinary tract infection has been proposed as a urinary tract malformation marker.

Insulating traveling-wave electrophoresis.

Traveling-wave electrophoresis (TWE) is a method for transporting charged colloidal particles used in many microfluidic techniques for particle manipulation and fractionation. This method exploits the traveling-wave components of the electric field generated by an array of electrodes subjected to ac voltages with a phase delay between neighboring electrodes. In this article, we propose an alternative way of generating traveling-wave electric fields in microchannels.

Low-frequency electrokinetics in a periodic pillar array for particle separation.

Deterministic Lateral Displacement (DLD) exploits periodic arrays of pillars inside microfluidic channels for high-precision sorting of micro- and nano-particles. Previously we demonstrated how DLD separation can be significantly improved by the addition of AC electrokinetic forces, increasing the tunability of the technique and expanding the range of applications. At high frequencies of the electric field (>1 kHz) the behaviour of such systems is dominated by Dielectrophoresis (DEP), whereas at low frequencies the particle behaviour is much richer and more complex.

Streptococcus pyogenes infections in Spanish children before and after the COVID pandemic. Coming back to the previous incidence.

Introduction: Group A Streptococcus (GAS) causes mild diseases, and unfrequently invasive infections (iGAS). Following the December 2022 alert from the United Kingdom regarding the unusual increase in GAS and iGAS infections, we analyzed the incidence of GAS infections in 2018-2022 in our hospital.

Methods: We conducted a retrospective study of patients seen in a pediatric emergency department (ED) diagnosed with streptococcal pharyngitis and scarlet fever and patients admitted for iGAS during last 5 years.

An Adolescent Female With Acute Abdominal Pain: A Rare Case in Pediatrics.

We present the case of a 13-year-old female with a 48-hour history of diffuse abdominal pain, fever, nausea, and vomiting, with worsening in the last few hours. On examination, she had signs of acute abdomen, and laboratory tests showed elevated acute phase reactants (APR). Abdominal ultrasound excluded acute appendicitis.

Scattering of Metal Colloids by a Circular Post under Electric Fields.

We consider the scattering of metal colloids in aqueous solutions by an insulating circular post under the action of an AC electric field. We analyze the effects on the particle of several forces of electrical origin: the repulsion between the induced dipole of the particle and its image dipole in the post, the hydrodynamic interaction with the post due to the induced-charge electroosmotic (ICEO) flow around the particle, and the dielectrophoresis arising from the distortion of the applied electric field around the post. The relative influence of these forces is discussed as a function of frequency of the AC field, particle size and distance to the post.

Balancing the Risks and Benefits of Pet Ownership in Pediatric Transplant Recipients.

In recent decades, the number of pediatric transplantations and their survival rates have increased. Psychological problems and poorer quality of life are notable among children undergoing transplantation and can have long-lasting consequences and affect immunosuppressive therapy adherence. Pet ownership and animal contact have been associated with physical, mental, and social health benefits.

Amoxicillin overdose in the pediatric emergency department: A descriptive study.

Objective: To describe the characteristics of pediatric patients treated in the  emergency department due to amoxicillin overdosing.

Method: A retrospective single-center observational study was conducted on  patients aged 0 to 16 years treated in a pediatric emergency department due  to amoxicillin overdosing between 2011 and 2021. Epidemiological and  anthropometric data was collected as well as information on the circumstances  of overdosing, clinical manifestations, emergency department management,  and discharge destination.

Pets for pediatric transplant recipients: To have or not to have.

Pets have many health, emotional and social benefits for children, but the risk of zoonotic infections cannot be underestimated, especially for immunosuppressed patients. We report the recommendations given by health professionals working with pediatric transplant recipients to their families regarding pet ownership. An online survey addressing zoonosis knowledge and recommendations provided by health care practitioners regarding pets was distributed to clinicians treating pediatric transplant recipients.

The role of particle-electrode wall interactions in mobility of active Janus particles driven by electric fields.

Hypothesis: The interaction of active particles with walls can explain discrepancies between experiments and theory derived for particles in the bulk. For an electric field driven metallodielectric Janus particle (JP) adjacent to an electrode, interaction between the asymmetric particle and the partially screened electrode yields a net electrostatic force - termed self-dielectrophoresis (sDEP) - that competes with induced-charge electrophoresis (ICEP) to reverse particle direction.

Experiments: The potential contribution of hydrodynamic flow to the reversal is evaluated by visualizing flow around a translating particle via micro-particle image velocimetry and chemically suppressing ICEP with poly(l-lysine)-g-poly(ethylene glycol) (PLL-PEG).

Wall Repulsion of Charged Colloidal Particles during Electrophoresis in Microfluidic Channels.

Electrophoresis describes the motion of charged particles suspended in electrolytes when subjected to an external electric field. Previous experiments have shown that particles undergoing electrophoresis are repelled from nearby channel walls, contrary to the standard description of electrophoresis that predicts no hydrodynamic repulsion. Dielectrophoretic (DEP) repulsive forces have been commonly invoked as the cause of this wall repulsion.

A Cyanotic Infant: Infrequent Presentation of Cow's Milk Protein Allergy.

We report the case of a three-month-old boy who presented with poor weight gain, loose stools, and poor oral intake for three weeks. Physical examination revealed a pale infant with abdominal distension and cyanosis. Oxygen saturation was normal, but the laboratory showed important methemoglobinemia.

Short communication: A simple and accurate method of measuring the zeta-potential of microfluidic channels.

We describe an improved method for determining the electroosmotic mobility and zeta potential of surfaces based on a current-monitoring method. This technique eliminates the requirement for measurements of channel dimensions and sample conductivities, leading to a simple high precision measurement. The zeta potential of PDMS is measured for native surfaces and surfaces treated with a nonionic surfactant in low-conductivity electrolytes.