Publications by authors named "Niels Larsen"

Specialized or secondary metabolites are small molecules of biological origin, often showing potent biological activities with applications in agriculture, engineering and medicine. Usually, the biosynthesis of these natural products is governed by sets of co-regulated and physically clustered genes known as biosynthetic gene clusters (BGCs). To share information about BGCs in a standardized and machine-readable way, the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard and repository was initiated in 2015.

View Article and Find Full Text PDF

Hypokalaemia is a common electrolyte disorder affecting hospitalised patients. It is associated with adverse outcomes including increased mortality. Inpatients with hypokalaemia need a different approach to workup and management as the aetiologies and progression of the hypokalaemia are distinct to outpatients.

View Article and Find Full Text PDF

Velocity estimation in ultrasound imaging is a technique to measure the speed and direction of blood flow. The flow velocity in small blood vessels, i.e.

View Article and Find Full Text PDF

Super-resolution ultrasound imaging using the erythrocytes (SURE) has recently been introduced. The method uses erythrocytes as targets instead of fragile microbubbles (MBs). The abundance of erythrocyte scatterers makes it possible to acquire SURE data in just a few seconds compared with several minutes in ultrasound localization microscopy (ULM) using MBs.

View Article and Find Full Text PDF

The oral bioavailability of therapeutic peptides is generally low. To increase peptide transport across the gastrointestinal barrier, permeation enhancers are often used. Despite their widespread use, mechanistic knowledge of permeation enhancers is limited.

View Article and Find Full Text PDF

Background: There is a long-standing tradition of honours education in the field of nursing, dating back to the early 1960s in the United States. However, its adoption in European and particularly Scandinavian egalitarian educational contexts is relatively recent.

Purpose: This scoping review aims to provide an analysis of the global utilisation and distribution of honours education within the field of nursing.

View Article and Find Full Text PDF

Hepatic in vitro models that accurately replicate phenotypes and functionality of the human liver are needed for applications in toxicology, pharmacology and biomedicine. Notably, it has become clear that liver function can only be sustained in 3D culture systems at physiologically relevant cell densities. Additionally, drug metabolism and drug-induced cellular toxicity often follow distinct spatial micropatterns of the metabolic zones in the liver acinus, calling for models that capture this zonation.

View Article and Find Full Text PDF
Article Synopsis
  • Capacitive micromachined ultrasonic transducers (CMUTs) have a nonlinear voltage-signal relationship that can hinder traditional contrast enhanced ultrasound (CEUS) techniques.
  • A new three-pulse amplitude modulation (AM) sequence has been introduced to mitigate these issues, showing better results with CMUTs compared to the conventional methods.
  • Experimental results indicate that CMUTs can produce effective CEUS images with minimal degradation in signal quality, achieving high contrast-to-tissue ratio improvements using this new sequence.
View Article and Find Full Text PDF

Human pluripotent stem cells (hPSCs) are intrinsically able to self-organize into cerebral organoids that mimic features of developing human brain tissue. These three-dimensional structures provide a unique opportunity to generate cytoarchitecture and cell-cell interactions reminiscent of human brain complexity in a dish. However, current brain organoid methodologies often result in intra-organoid variability, limiting their use in recapitulating later developmental stages as well as in disease modeling and drug discovery.

View Article and Find Full Text PDF

We demonstrate the transfer and immobilization of active antibodies from a low surface- energy mold surface to thermoplastic replica surfaces using injection molding, and we investigate the process at molecular scale. The transfer process is highly efficient, as verified by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) of the mold and replica surfaces. AFM analysis reveals partial nanometer-scale embedding of the protein into the polymer matrix as a possible mechanism of permanent immobilization.

View Article and Find Full Text PDF

Sufficient and controllable oxygen supply is essential for 3D cell and tissue culture at high cell densities, which calls for volumetric oxygen analysis methods to quantitatively assess the oxygen distribution. This paper presents a general approach for accurate and precise non-contact 3D mapping of oxygen tension in high cell-density cultures embedded commercially available oxygen microsensor beads read out by confocal phosphorescence lifetime microscopy (PLIM). Optimal acquisition conditions and data analysis procedures are established and implemented in a publicly available software package.

View Article and Find Full Text PDF

Background: Traumatic brain injury significantly impacts survivors and their families. Rehabilitation following traumatic brain injury is often complex due to the physical, psychological, and socio-economic problems survivors face. Life goals are considered a motivational factor in rehabilitation.

View Article and Find Full Text PDF

Human in vitro models of neural tissue with tunable microenvironment and defined spatial arrangement are needed to facilitate studies of brain development and disease. Towards this end, embedded printing inside granular gels holds great promise as it allows precise patterning of extremely soft tissue constructs. However, granular printing support formulations are restricted to only a handful of materials.

View Article and Find Full Text PDF

Atherosclerotic cardiovascular disease is the leading cause of death worldwide. For decades, mouse modeling of atherosclerosis has been the mainstay for preclinical testing of genetic and pharmacological intervention. Mouse models of atherosclerosis depend on supraphysiological levels of circulating cholesterol carried in lipoprotein particles.

View Article and Find Full Text PDF

small intestinal models aim to mimic the intestinal function and structure, including the villi architecture of the native tissue. Accurate models in a scalable format are in great demand to advance, for example, the development of orally administered pharmaceutical products. Widely used planar intestinal cell monolayers for compound screening applications fail to recapitulate the three-dimensional (3D) microstructural characteristics of the intestinal villi arrays.

View Article and Find Full Text PDF

Oral delivery is a highly preferred method for drug administration due to high patient compliance. However, oral administration is intrinsically challenging for pharmacologically interesting drug classes, in particular pharmaceutical peptides, due to the biological barriers associated with the gastrointestinal tract. In this review, we start by summarizing the pharmacological performance of several clinically relevant orally administrated therapeutic peptides, highlighting their low bioavailabilities.

View Article and Find Full Text PDF

This study evaluates the use of 3D printed phantoms for 3D super-resolution ultrasound imaging (SRI) algorithm calibration. The main benefit of the presented method is the ability to do absolute 3D micro-positioning of sub-wavelength sized ultrasound scatterers in a material having a speed of sound comparable to that of tissue. Stereolithography is used for 3D printing soft material calibration micro-phantoms containing eight randomly placed scatterers of nominal size 205 μm × 205 μm × 200 μm.

View Article and Find Full Text PDF
Article Synopsis
  • * The system takes advantage of the switching from hydrophobic SP to hydrophilic merocyanine when irradiated, affecting drug release dynamics by altering intermolecular interactions and suppressing premature release.
  • * A thermodynamic model using Hansen solubility parameters successfully predicts and optimizes the system's performance, demonstrating efficient light-triggered release (90-95%) for various drugs, including dopamine and prednisone, highlighting the model's relevance in drug release research.
View Article and Find Full Text PDF
Article Synopsis
  • Delay-and-sum (DAS) beamforming struggles with high-density scatterer detection, leading to overlapping point spread functions that complicate identification.
  • A convolutional neural network (CNN) was developed to process radio frequency channel data and create non-overlapping Gaussian confidence maps, effectively localizing scatterers even beyond DAS resolution limits.
  • In tests with simulated and measured data, the CNN achieved high precision and recall rates, showing promise for applications like better detection of microbubbles in super-resolution ultrasound imaging.
View Article and Find Full Text PDF

In Parkinson's disease, the degeneration of dopaminergic neurons in substantia nigra leads to a decrease in the physiological levels of dopamine in striatum. The existing dopaminergic therapies effectively alleviate the symptoms, albeit they do not revert the disease progression and result in significant adverse effects. Transplanting dopaminergic neurons derived from stem cells could restore dopamine levels without additional motor complications.

View Article and Find Full Text PDF

We present a method for reproducible manufacture of multiassay platforms with tunable mechanical properties for muscle tissue strip analysis. The platforms result from stereolithographic 3D printing of low protein-binding poly(ethylene glycol) diacrylate (PEGDA) hydrogels. Contractile microtissues have previously been engineered by immobilizing suspended cells in a confined hydrogel matrix with embedded anchoring cantilevers to facilitate muscle tissue strip formation.

View Article and Find Full Text PDF

Background: Non-gonococcal urethritis (NGU) is a common syndrome in men. NGU may have several causes, but many cases are caused by sexually transmitted infections that may also cause complications in their female partners. Chlamydia trachomatis and Mycoplasma genitalium are the most common causes of NGU, but in up to 35% of the cases, none of the known viral or bacterial causes are found.

View Article and Find Full Text PDF

Three-dimensional (3D) in vitro models capturing both the structural and dynamic complexity of the in vivo situation are in great demand as an alternative to animal models. Despite tremendous progress in engineering complex tissue/organ models in the past decade, approaches that support the required freedom in design, detail and chemistry for fabricating truly 3D constructs have remained limited. Here, we report a stereolithographic high-resolution 3D printing technique utilizing poly(ethylene glycol) diacrylate (PEGDA, MW 700) to manufacture diffusion-open and mechanically stable hydrogel constructs as self-contained chips, where confined culture volumes are traversed and surrounded by perfusable vascular-like networks.

View Article and Find Full Text PDF

The objective of this study was to delineate the effects of different coffee processing residues on the anaerobic microbes and corresponding digestion performance. The results elucidated that mucilage-rich feed enhanced the accumulation of methanogens, which consequently led to better digestion performance of biogas production. Fifty percent more methane and up to 3 times more net energy (heat and electricity) output were achieved by the digestion of the mucilage-rich feed (M3).

View Article and Find Full Text PDF