Publications by authors named "Leijon A"

RNA therapies have recently taken a giant leap forward with the approval of Onpattro™, a siRNA therapy delivered using a lipid nanoparticle (LNP), and the LNP-enabled mRNA vaccines against COVID-19, which are the first mRNA drugs to reach the marketplace. The latter medicines have illustrated that stability is a significant challenge in the distribution of RNA drugs using non-viral delivery systems, particularly in areas without cold chain storage. Here, we describe a proof-of-concept study on the engineering of an LNP mRNA formulation suitable for spray drying.

View Article and Find Full Text PDF

This paper presents a new Bayesian method for analyzing Ecological Momentary Assessment (EMA) data and applies this method in a re-analysis of data from a previous EMA study. The analysis method has been implemented as a freely available Python package , RRID:SCR 022943. The analysis model can use EMA input data including nominal categories in one or more situation dimensions, and ordinal ratings of several perceptual attributes.

View Article and Find Full Text PDF

Background: In the last decades, the average age for toilet training has increased in the western world. It is suggested that the postponed initiation of toilet training is a contributing factor to problems related to bowel and bladder control. Functional gastrointestinal and urinary tract disorders are prevalent in childhood, causing suffering in affected children and for their families, and consuming healthcare resources.

View Article and Find Full Text PDF

Determination of the nutritional condition, including estimation of amounts of total body fat (tBF), at routine postmortem examination of cats is typically based on subjective visual assessment. Subjective assessment may result in uncertainties regarding degree of overweight, and objective methods that provide a numerical value reflecting the tBF could be valuable to accurately judge excess body fat. We investigated if the falciform fat pad weight (FFPW) was correlated to tBF and could be used to detect overweight and obesity in cats.

View Article and Find Full Text PDF

Elbow osteoarthritis (OA) is common in cats and radiography is typically used for diagnosis. However computed tomography (CT), with its multiplanar three-dimensional characteristics, could have significant advantages for assessment of OA compared to radiography, particularly early in the disease process. The study objectives were to compare radiography and CT to histologic OA changes, investigate the stage of OA that radiography and CT detect, and search for specific changes in CT images strongly predictive for feline elbow OA.

View Article and Find Full Text PDF

The development and early morphological features of feline hip osteoarthritis (OA) are largely unknown. Tears in the acetabular labrum and at the chondrolabral transition zone are suggested to be important in the pathogenesis of human hip OA, but in cats such lesions have not been described. We investigated associations between computed tomography (CT)-detected joint changes and microscopic articular cartilage lesions, the distribution of detected changes, and histologically evaluated the acetabular margin (AM) in hip joints from 20 cats.

View Article and Find Full Text PDF

Severe cardiomegaly with an atrial septal defect was discovered during necropsy of a subadult White-tailed Eagle (Haliaeetus albicilla) found dead in the wild. A thin membrane composed of fibromuscular tissue separated the left atrium into two chambers, most consistent with that described for cor triatriatum sinister (CTS) in other species. Seventeen months later, necropsy of an adult White-tailed Eagle again revealed CTS.

View Article and Find Full Text PDF

Objective: IOI-HA response data are conventionally analysed assuming that the ordinal responses have interval-scale properties. This study critically considers this assumption and compares the conventional approach with a method using Item Response Theory (IRT).

Design: A Bayesian IRT analysis model was implemented and applied to several IOI-HA data sets.

View Article and Find Full Text PDF

Background: Thoracolumbar myelopathies associated with spinal cord and vertebral column lesions, with a similar clinical phenotype, but different underlying etiologies, occur in pugs.

Objectives: To further characterize the clinical and neuropathological characteristics of pugs with longstanding thoracolumbar myelopathy.

Animals: Thirty client-owned pure-bred pugs with a history of more than a month of ataxia and paresis of the pelvic limbs, suggesting a myelopathy localized to the thoracolumbar spinal cord, were included in the study.

View Article and Find Full Text PDF

This paper presents a method to analyze paired-comparison data including either binary or graded ordinal responses, with or without ties. The proposed method can use either of two classical choice models: (1) Thurstone case V, which assumes a Gaussian distribution of the sensory variables underlying listener decisions, or (2) the Bradley-Terry-Luce (BTL) model, which assumes a logistic distribution. The analysis method was validated using simulated paired-comparison experiments with known distributions of the sound-quality parameters in the simulated population from which "participants" were generated at random.

View Article and Find Full Text PDF

Feline stifle osteoarthritis (OA) is common, however little is known about the early stages of the disease. Furthermore, the importance of small articular mineralizations (AMs) in feline stifle OA is controversial. This study aimed to describe microscopic articular cartilage lesions and to investigate associations between cartilage lesions and AMs, synovitis, osteochondral junction findings and subchondral bone sclerosis.

View Article and Find Full Text PDF

In this paper, we propose novel strategies for neutral vector variable decorrelation. Two fundamental invertible transformations, namely, serial nonlinear transformation and parallel nonlinear transformation, are proposed to carry out the decorrelation. For a neutral vector variable, which is not multivariate-Gaussian distributed, the conventional principal component analysis cannot yield mutually independent scalar variables.

View Article and Find Full Text PDF

Background: Neurodegenerative diseases are a heterogeneous group of disorders characterized by loss of neurons and are commonly associated with a genetic mutation.

Hypothesis/objectives: To characterize the clinical and histopathological features of a novel degenerative neurological disease affecting the brain of young adult Nova Scotia Duck Tolling Retrievers (NSDTRs).

Animals: Nine, young adult, related NSDTRs were evaluated for neurological dysfunction and rapid eye movement sleep behavior disorder.

View Article and Find Full Text PDF
Variational Inference for Watson Mixture Model.

IEEE Trans Pattern Anal Mach Intell

September 2016

This paper addresses modelling data using the Watson distribution. The Watson distribution is one of the simplest distributions for analyzing axially symmetric data. This distribution has gained some attention in recent years due to its modeling capability.

View Article and Find Full Text PDF

A novel Bayesian matrix factorization method for bounded support data is presented. Each entry in the observation matrix is assumed to be beta distributed. As the beta distribution has two parameters, two parameter matrices can be obtained, which matrices contain only nonnegative values.

View Article and Find Full Text PDF

This paper addresses the Bayesian estimation of the von-Mises Fisher (vMF) mixture model with variational inference (VI). The learning task in VI consists of optimization of the variational posterior distribution. However, the exact solution by VI does not lead to an analytically tractable solution due to the evaluation of intractable moments involving functional forms of the Bessel function in their arguments.

View Article and Find Full Text PDF

A number of measures were evaluated with regard to their ability to predict the speech-recognition benefit of single-channel noise reduction (NR) processing. Three NR algorithms and a reference condition were used in the evaluation. Twenty listeners with impaired hearing and ten listeners with normal hearing participated in a blinded laboratory study.

View Article and Find Full Text PDF

Objectives: The rapidly evolving field of early diagnostics after the introduction of newborn hearing screening requires rapid, valid, and objective methods, which have to be thoroughly evaluated in adults before use in infants. The aim was to study cross-correlation analysis of interleaved auditory brainstem responses (ABRs) in a wide dynamic range in normal-hearing adults. Off-line analysis allowed for comparison with psychoacoustical click threshold (PCT), pure-tone threshold, and determination of ABR input/output function.

View Article and Find Full Text PDF

Bayesian estimation of the parameters in beta mixture models (BMM) is analytically intractable. The numerical solutions to simulate the posterior distribution are available, but incur high computational cost. In this paper, we introduce an approximation to the prior/posterior distribution of the parameters in the beta distribution and propose an analytically tractable (closed form) Bayesian approach to the parameter estimation.

View Article and Find Full Text PDF

In the framework of the European HearCom project, promising signal enhancement algorithms were developed and evaluated for future use in hearing instruments. To assess the algorithms' performance, five of the algorithms were selected and implemented on a common real-time hardware/software platform. Four test centers in Belgium, The Netherlands, Germany, and Switzerland perceptually evaluated the algorithms.

View Article and Find Full Text PDF

Spermatozoa are the most diverse of all animal cells. Variation in size alone is enormous and yet there are still no clear evolutionary explanations that can account for such diversity. The basic genetics of sperm form is also poorly understood, although sperm size is known to have a strong genetic component.

View Article and Find Full Text PDF

In a laboratory study, we found that normal-hearing and hearing-impaired listeners preferred less than normal overall calculated loudness (according to a loudness model of Moore & Glasberg, 1997). The current study verified those results using a research hearing aid. Fifteen hearing-impaired and eight normal-hearing participants used the hearing aid in the field and adjusted a volume control to give preferred loudness.

View Article and Find Full Text PDF

This study questions the basic assumption that prescriptive methods for nonlinear, wide dynamic range compression (WDRC) hearing aids should restore overall loudness to normal. Fifteen normal-hearing listeners and twenty-four hearing-impaired listeners (with mild to moderate hearing loss, twelve with and twelve without hearing aid experience) participated in laboratory tests. The participants first watched and listened to video sequences and rated how loud and how interesting the situations were.

View Article and Find Full Text PDF

Methodology is proposed for perceptual assessment of both subjective sound quality and speech recognition in such way that results can be compared between these two aspects. Validation is performed with a noise suppression system applied to hearing instruments. A method termed Interpolated Paired Comparison Rating (IPCR) was developed for time efficient assessment of subjective impression of different aspects of sound quality for a variety of noise conditions.

View Article and Find Full Text PDF