Publications by authors named "Balk A"

Introduction: Point-of-care ultrasonography (POCUS) is increasingly utilized in emergency departments (EDs) throughout Thailand. Although emergency medicine (EM) residents are trained in POCUS, Thai medical students receive limited training. An introductory POCUS course was implemented for medical students to prepare them for internships.

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Bubbles have a rich history as transducers in particle-physics experiments. In a solid-state analogue, we use bubble domains in nanomagnetic films to measure magnetic nanoparticles. This technique can determine the magnetic orientation of a single nanoparticle in a fraction of a second and generate a full hysteresis loop in a few seconds.

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Manual assembly of atomically thin materials into heterostructures with desirable electronic properties is an approach that holds great promise. Despite the rapid expansion of the family of ultrathin materials, stackable and stable ferro/ferri magnets that are functional at room temperature are still out of reach. We report the growth of air-stable, transferable ultrathin iron oxide crystals that exhibit magnetic order at room temperature.

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We use scanning optical magnetometry to study the broadband frequency spectra of spontaneous magnetization fluctuations, or "magnetization noise", in an archetypal ferromagnetic film that can be smoothly tuned through a spin reorientation transition (SRT). The SRT is achieved by laterally varying the magnetic anisotropy across an ultrathin Pt/Co/Pt trilayer, from the perpendicular to in-plane direction, via graded Ar irradiation. In regions exhibiting perpendicular anisotropy, the power spectrum of the magnetization noise, (), exhibits a remarkably robust power law over frequencies from 1 kHz to 1 MHz.

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Poor water solubility of drugs fuels complex formulations and jeopardizes patient access to medication. Simplifying these complexities we systematically synthesized a library of 36 sterically demanding counterions and mapped the pharmaceutical design space for amorphous ionic liquid strategies for Selurampanel, a poorly water soluble drug used against migraine. Patients would benefit from a rapid uptake after oral administration to alleviate migraine symptoms.

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Objective: A high intrapatient variability in tacrolimus exposure is associated with poor long-term outcomes after kidney transplant. We hypothesized that a high intrapatient variability of tacrolimus exposure after heart transplant may be associated with cardiac allograft vasculopathy as a determinant of long-term survival of heart transplant recipients.

Materials And Methods: Eighty-six heart transplant recipients were included.

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Magneto-optical Kerr effect (MOKE) microscopy measurements of magnetic bubble domains demonstrate that Ar^{+} irradiation around 100 eV can tune the Dzyaloshinskii-Moriya interaction (DMI) in Pt/Co/Pt trilayers. Varying the irradiation energy and dose changes the DMI sign and magnitude separately from the magnetic anisotropy, allowing tuning of the DMI while holding the coercive field constant. This simultaneous control emphasizes the different physical origins of these effects.

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We use scanning electron microscopy with polarization analysis to image deterministic, spin-orbit torque-driven magnetization reversal of in-plane magnetized CoFeB rectangles in zero applied magnetic field. The spin-orbit torque is generated by running a current through heavy metal microstrips, either Pt or Ta, upon which the CoFeB rectangles are deposited. We image the CoFeB magnetization before and after a current pulse to see the effect of spin-orbit torque on the magnetic nanostructure.

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Background: Cardiac allograft vasculopathy (CAV) is a multifactorial disease and a major cause of graft failure after heart transplantation. However, the impact of CAV may vary according to the definition and the regional differences in transplantation settings.

Objectives: We sought to assess CAV prevalence, predictors and prognosis in Dutch heart transplant recipients based on coronary angiography, following the 2010 standard nomenclature of the International Society for Heart and Lung Transplantation.

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We have used scanning electron microscopy with polarization analysis and photoemission electron microscopy to image the two-dimensional magnetization of permalloy films patterned into Penrose P2 tilings (P2T). The interplay of exchange interactions in asymmetrically coordinated vertices and short-range dipole interactions among connected film segments stabilize magnetically ordered, spatially distinct sublattices that coexist with frustrated sublattices at room temperature. Numerical simulations that include long-range dipole interactions between sublattices agree with images of as-grown P2T samples and predict a magnetically ordered ground state for a two-dimensional quasicrystal lattice of classical Ising spins.

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Objective: Over the past decades donor and recipient characteristics and medical management of heart transplantations patients have changed markedly. We studied the impact of these changes on long-term clinical outcome.

Design And Methods: Data of all consecutive heart transplant recipients in our center have been collected prospectively.

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Study Objective: This study compares first pass success rates and patient and physician satisfaction scores of using a guide wire-associated peripheral venous catheter (GAPIV) vs a traditional peripheral venous catheter in difficult to obtain venous access patients.

Methods: A total of 200 patients were enrolled prospectively from a convenience sample in a large urban academic emergency department. Patients were included when they were deemed difficult access per study criteria.

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The topological nature of magnetic skyrmions leads to extraordinary properties that provide new insights into fundamental problems of magnetism and exciting potentials for novel magnetic technologies. Prerequisite are systems exhibiting skyrmion lattices at ambient conditions, which have been elusive so far. Here, we demonstrate the realization of artificial Bloch skyrmion lattices over extended areas in their ground state at room temperature by patterning asymmetric magnetic nanodots with controlled circularity on an underlayer with perpendicular magnetic anisotropy (PMA).

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Ionic liquids (ILs) are organic salts with a melting point below 100°C. Active pharmaceutical ingredients (APIs) are transformed into ILs by combining them with typically large yet charged counterions. ILs hold promise to build a large design space for relevant pharmaceutical parameters, particularly for poorly water soluble drugs.

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Poor water solubility of active pharmaceutical ingredients (API) is a major challenge in drug development impairing bioavailability and therapeutic benefit. This study is addressing the possibility to tailor pharmaceutical and physical properties of APIs by transforming these into tetrabutylphosphonium (TBP) salts, including the generation of ionic liquids (IL). Therefore, poorly water soluble acidic APIs (Diclofenac, Ibuprofen, Ketoprofen, Naproxen, Sulfadiazine, Sulfamethoxazole, and Tolbutamide) were converted into TBP ILs or low melting salts and compared to the corresponding sodium salts.

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Purpose: A poorly water soluble acidic active pharmaceutical ingredient (API) was transformed into an ionic liquid (IL) aiming at faster and higher oral availability in comparison to a prodrug.

Methods: API preparations were characterized in solid state by single crystal and powder diffraction, NMR, DSC, IR and in solution by NMR and ESI-MS. Dissolution and precipitation kinetics were detailed as was the role of the counterion on API supersaturation.

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Over the past decades donor and recipient characteristics and medical management of heart transplantation (HT) patients have changed markedly. We studied the impact of these changes on long-term clinical outcome. Data of all consecutive HT recipients in our center have been collected prospectively.

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We measure the microvortical flows around gold nanorods propelled by ultrasound in water using polystyrene nanoparticles as optical tracers. We infer the rotational frequencies of such nanomotors assuming a hydrodynamic model of this interaction. In this way, we find that nanomotors rotate around their longitudinal axes at frequencies of up to ≈ 2.

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Aims: Beta-blockers improve the prognosis in heart failure (HF), but their introduction may seem impossible in patients dependent on inotropic support. However, many of these patients can be titrated on beta-blockers, but there is little evidence of successful clinical strategies.

Methods And Results: We analysed the records of inotropy-dependent patients referred for assessment for heart transplantation.

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Background: Conflicting data have been reported about the effect of Toxoplasma serostatus on mortality after heart transplantation. Either a positive or a negative recipient Toxoplasma serostatus was found to be associated with increased mortality.

Methods: We evaluated the effects of T.

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Background: Recent reports have shown that hepatitis E virus (HEV) infection can become chronic in solid-organ transplant recipients, but few studies have systematically investigated the clinical consequences of this chronic HEV infection in solid-organ transplant (SOT) recipients.

Methods: We have undertaken an in-depth study of 6 chronic HEV-infected heart transplant recipients to gain further insight into the clinical, biochemical and virologic presentation of this disorder.

Results: In 6 patients (2.

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Noncompaction cardiomyopathy (NCC) is a primary cardiomyopathy characterized by an excessively prominent trabecular meshwork and deep intertrabecular recesses of the left ventricular walls. Most cases are inherited, with a dominant inheritance pattern. The aim of the present study was to determine the prevalence and clinical characteristics of cardiomyopathies in the close relatives of patients with NCC.

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