Jozef Kaiser

Brno University of Technology · Central European Institute of Technology "CEITEC"

The development of craniofacial skeletal structures is fascinatingly complex and elucidation of the underlying mechanisms will not only provide novel scientific insights, but also help develop more effective clinical approaches to the treatment and/or prevention of the numerous congenital craniofacial malformations. To this end, we performed CAGE-s...

Computational modeling plays an important role in assessment of biomaterial structures, living tissue and their mechanical properties. Microstructure investigation of bone tissue needs high-level computational models based on μ-CT images. A crucial factor when creating a computational model is image processing using tissue segmentation. The most co...

The mutual incompatibility of distinct spectroscopic systems is among the most limiting factors in Laser-Induced Breakdown Spectroscopy (LIBS). The cost related to setting up a new LIBS system is increased,...

Laser-Induced Breakdown Spectroscopy (LIBS) has established its position as a method for the analysis of biological samples. We aim to introduce the benefits of LIBS for the qualitative elemental imaging of tissues. The state-of-the-art instrumentation enables elemental imaging of sample surfaces with a high resolution (down to micro-scale) on a la...

Metallic porous structures (scaffolds) produced by additive manufacturing represent an important class of personalised implants used in load-bearing orthopaedic applications. As such, their fatigue performance must be excellent to prevent the need for revision surgery. This paper provides insight into the high-cycle fatigue behaviour of novel titan...

Misalignment of the rotation axis causes severe artifacts in X-ray computed tomography. Calibration of this parameter is often insufficient for sub-micron resolution measurements and needs to be corrected during the post-processing. This correction can be accelerated by various automatic methods. These vary in mechanisms and performance, making the...

Cross-section preparation of painting micro-samples is part of their routine analysis. This type of preparation can be used for several analytical techniques, such as scanning electron microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and optical microscopy. These techniques offer high-resolution imaging and/or elemental info...

Scanning electron microscopy (SEM) is a common method for the analysis of painting micro-samples. The high resolution of this technique offers precise surface analysis and can be coupled with an energy-dispersive spectrometer for the acquisition of the elemental composition. For light microscopy and SEM analysis, the painting micro-samples are comm...

There are major differences in duration and scale at which limb development and regeneration proceed, raising the question to what extent regeneration is a recapitulation of development. We address this by analyzing skeletal elements using a combination of micro-CT imaging, molecular profiling and clonal cell tracing. We find that, in contrast to d...

Spontaneous bleeds are a leading cause of death in the pediatric JAG1-related liver disease Alagille syndrome (ALGS). We asked whether there are sex differences in bleeding events in patients, whether Jag1Ndr/Ndr mice display bleeds or vascular defects, and whether discovered vascular pathology can be confirmed in patients non-invasively. We perfor...

Microplastics found in the environment are often covered with a biofilm, which makes their analysis difficult. Therefore, the biofilm is usually removed before analysis, which may affect the microplastic particles or lead to their loss during the procedure. In this work, we used laser-based analytical techniques and evaluated their performance in d...

Characterization of brain infarct lesions in rodent models of stroke is crucial to assess stroke pathophysiology and therapy outcome. Until recently, the analysis of brain lesions was performed using two techniques: (1) histological methods, such as TTC (Triphenyltetrazolium chloride), a time-consuming and inaccurate process; or (2) MRI imaging, a...

Laser‐induced plasma emission spectra contain vast amounts of information. Yet, the discovery of appropriate patterns in laser‐induced breakdown spectra is paramount to reliably performing both quantitative and qualitative analysis. This chapter provides a brief introduction of artificial neural network (ANN) classification models, which have recen...

This work thoroughly describes how three different types of photon-upconversion nanoparticles (UCNPs) that differ in size or composition influence a model plant Zea mays. This plant was treated with an aqueous dispersion of nanoparticles in a hydroponic short-term toxicity test (168 h) in three different concentrations (0.5, 5, and 25 μg/mL of yttr...

The mutual incompatibility of distinct spectroscopic systems is among the most limiting factors in Laser-Induced Breakdown Spectroscopy (LIBS). The cost related to setting up a new LIBS system is increased, as its extensive calibration is required. Solving the problem would enable inter-laboratory reference measurements and shared spectral librarie...

Aging of lithium-ion batteries is especially important for applications such as battery electric vehicles, where they constitute a major part of the total cost and practically determine product lifetime. One of the main problems during cycle aging is the swelling of the electrode stack, as this results in increased mechanical stresses inside batter...

The present work explores the applicability of a single spectroscopic technique, Laser-induced breakdown spectroscopy (LIBS), for the rapid quality assessment and quantification of individual layers of an amorphous bilayer ribbon (thickness ~ 35 μm). This kind of materials (ribbon) offer a convolution of the two sets of unique properties of individ...

Archeological ceramic is full of information from the socio-economic relations within a society to the food storage practices. Various admixtures are added to enhance specific properties of the ceramic. Hay is an under evaluated admixture and when fired, the organic part partially or fully “disappears”, thus making it harder to identify. The organi...

We report on combining the surface analysis technique of Laser-induced Breakdown Spectroscopy (LIBS) with Raman spectroscopy. The combination of both techniques enables to study the chemical composition of the sample in a broader context when combining elemental and molecular information. Obtained elemental and molecular spectra are characteristic...

The chromium and copper contamination of algae on a filter was directly monitored with laser-induced breakdown spectroscopy (LIBS) as a demonstration of LIBS capabilities. Liquid samples of the green alga Desmodesmus subspicatus were intentionally contaminated with chromium, incubated, filtered, and the filters with the algae were analysed. Inducti...

Archeological ceramic is full of information from the socio-economic relations within a society to the food storage practices. Various admixtures are added to enhance specific properties of the ceramic. Hay is an under evaluated admixture and when fired, the organic part partially or fully “disappears”, thus making it harder to identify. The organi...

Complementary methods are introduced to laser-induced breakdown spectroscopy measurement systems in order to provide complete information about the investigated sample, phenomena beyond laser-matter interaction and evolution of laser-induced plasmas and its properties. Another use of such complementary signals is in their potential use for signal s...

Adrenal glands are the major organs releasing catecholamines and regulating our stress response. The mechanisms balancing generation of adrenergic chromaffin cells and protecting against neuroblastoma tumors are still enigmatic. Here we revealed that serotonin (5HT) controls the numbers of chromaffin cells by acting upon their immediate progenitor...

The complex shape of embryonic cartilage represents a true challenge for phenotyping and basic understanding of skeletal development. X-ray computed microtomography (μCT) enables inspecting relevant tissues in all three dimensions; however, most 3D models are still created by manual segmentation, which is a time-consuming and tedious task. In this...

Reef-building corals are endangered animals with a complex colonial organization. Physiological mechanisms connecting multiple polyps and integrating them into a coral colony are still enigmatic. Using live imaging, particle tracking, and mathematical modeling, we reveal how corals connect individual polyps and form integrated polyp groups via spec...

Selective laser melting (SLM) is an additive manufacturing technology suitable for producing cellular lattice structures using fine metal powder and a laser beam. However, the shape and dimensional deviations occur on the thin struts during manufacturing, influencing the mechanical properties of the structure. There are attempts in the literature t...

Laser-Induced Breakdown Spectroscopy (LIBS) data obtained from the elemental imaging of heterogeneous samples are processed with various chemometric algorithms. The intention is to cluster obtained characteristic spectra and to provide additional information about the sample surface composition and distribution of individual matrices. However, ther...

Characterization of brain infarct lesion in rodent models of stroke is crucial to assess the outcome of stroke therapies and to study the disease pathophysiology. However, so far it has been mostly performed by: 1) histological methods, a time-consuming process that lead to significant flaws; or 2) via MRI imaging, which is faster, yielding 3D info...

Background Reptiles exhibit a large heterogeneity in teeth morphology. The main variability comprises the different tooth shape, the type of tooth attachment to the underlying bone, or the ability to replace the teeth. Findings Here, we provide full datasets of microtomography scans and 3D models of reptilian dentitions and skulls. We selected rep...

Spinal fusion is a surgical procedure used to join two or more vertebrae to prevent movement between them. This surgical procedure is considered in patients suffering from a wide range of degenerative spinal diseases or vertebral fractures. The success rate of spinal fusion is frequently evaluated subjectively using X-ray computed tomography. The p...

One of the critical factors that may significantly contribute to X-ray computed tomography measurement uncertainty is the misalignment of CT system components from ideal geometry assumed by tomographic reconstruction. It is proven to cause image artifacts, inhomogeneous magnification, thus leading to dimensional measurement errors. There is a lack...

In computed tomography, artifacts caused by metal objects pose a major challenge, as they severely degrade the final image. Reduction of these artifacts is a topic of ongoing research, and many possible approaches have been developed so far. Among these, projection completion methods are effective and reasonably simple to implement compared to othe...

The spatial resolution is still one of the essential parameters quantified in X-ray micro Computed Tomography for industrial applications. There is a number of approaches, how can be the spatial resolution determined. Our paper presents two of them: evaluation of the ruby sphere according to the ASTM E1695–95 guideline and bar pattern recognition i...

Characterization of brain infarct lesion in rodent models of stroke is crucial to assess the outcome of stroke therapies and to study the disease pathophysiology. However, so far it has been mostly performed by: 1) histological methods, a time-consuming process that lead to significant flaws and tissue distortion; or 2) via MRI imaging, which is fa...

This paper deals with the research of the Selective Laser Melting (SLM) scanning strategy to produce lattice structures from AlSi10Mg powder material. Nowadays, most of the SLM end-users use the laser strategy and parameters recommended by powder or machine suppliers to produce different components. However, this setup can cause material and shape...

Hollow SDD particles raise challenges with respect toappropriate and meaningful particle characterization. Whilstmeasurements of particle size and bulk density provide someinformation, the results can be confounded due to incorrectassumptions. Correspondingly, any correlation to powder/formulation properties may be erroneous or misleading.Quantitat...

Samples with different mechanical and physical properties were measured by LIBS under diverse experimental conditions. The results were used to train a neural network. By means of the neural network, the optimisation process was significantly reduced.

Laser-induced breakdown spectroscopy (LIBS) is a well-established analytical tool with relevance in extra-terrestrial exploration. Despite considerable efforts towards the development of calibration-free LIBS approaches, these are currently outperformed by calibration-based...

X-ray computed tomography is a common tool for non-destructive testing and analysis. One major application of this imaging technique is 3D porosity identification and quantification, which involves image segmentation of the analysed dataset. This segmentation step, which is most commonly performed using a global thresholding algorithm, has a major...

Laser-induced breakdown spectroscopy is often combined with a multivariate black box model—such as support vector machines (SVMs)—to obtain desirable quantitative or qualitative results. This approach carries obvious risks when practiced in high-stakes applications. Moreover, the lack of understanding of a black-box model limits the user's ability...

X-ray computed tomography is a 3D imaging technique that is able to provide information about both inner and outer parts of battery cells without their destruction. We will present this technique allowing us access to the batteries data in the whole range of scales – from the analysis of entire cells down to microstructure of electrodes. We will fo...

Considerable amount of research has been focused on dentin mineralization, odontoblast differentiation, and their application in dental tissue engineering. However, very little is known about the differential role of functionally and spatially distinct types of dental epithelium during odontoblast development. Here we show morphological and functio...

The Sprouty family is a highly conserved group of intracellular modulators of receptor tyrosine kinase (RTK)‐signaling pathways, which have been recently linked to primary cilia. Disruptions in the structure and function of primary cilia cause inherited disorders called ciliopathies. We aimed to evaluate Sprouty2 and Sprouty4 gene dependent alterat...

Direct ink writing, or robocasting, is an extrusion additive manufacturing technique for the fabrication of complex ceramic parts. Pores are common defects in post-sintered robocast parts that strongly influence the performance by changing the density, the transport properties, and the mechanical strength. In this work, the porosity (volumetric fra...

Melanocytes are pigmented cells residing mostly in the skin and hair follicles of vertebrates, where they contribute to colouration and protection against UV-B radiation. However, the spectrum of their functions reaches far beyond that. For instance, these pigment-producing cells are found inside the inner ear, where they contribute to the hearing...

X-ray computed-tomography is an established inspection technique for cultural heritage objects, but it is rarely used for painted micro-samples. These small, delicate, and complex parts of historical objects offer important and unique insights to conservators and restorers, but there is no standard method for preparing them nondestructively and wit...

Laser-induced plasma (LIP) is dependent on many experimental conditions, as well as on the material and type of the ablated sample. Typically, the spectral data from a LIP are used as an analytical tool. However, the problem is that the data suffer from instability of the plasma, matrix effect, shot-to-shot fluctuation, etc. One of the possibilitie...

Multi-level visualization of U-Zr mineralization in sandstones is discussed, aiming at the identification of mineral phases, imaging of their distribution using 2D and 3D projections, and quantification of the presence of U-rich domains. For this purpose, uranium-bearing sediments with anomalous concentrations of Zr, Nb ± Fe, Sr were studied (Břevn...

Recently nanoparticle enhanced Laser Induced Breakdown Spectroscopy (NELIBS) is getting a growing interest as an effective alternative method for improving the analytical performance of LIBS. On the other hand, the plasmonic effect during laser ablation can be used for a different task rather than elemental analysis. In this paper, the dependence o...

Many growth factors have been studied as additives accelerating lumbar fusion rates in different animal models. However, their low hydrolytic and thermal stability both in vitro and in vivo limits their workability and use. In the proposed work, a stabilized vasculogenic and prohealing fibroblast growth factor-2 (FGF2-STAB®) exhibiting a functional...

The main purpose of this work is to thoroughly describe the implementation protocol of laser-induced breakdown spectroscopy (LIBS) method in the plant analysis. Numerous feasibility studies and recent progress in instrumentation and trends in chemical analysis make LIBS an established method in plant bioimaging. In this work, we present an easy and...

Nowadays, laser-based techniques play a significant role in medicine, mainly in the ophthalmology, dermatology, and surgical fields. So far, they have presented mostly therapeutic applications, although they have considerable potential for diagnostic approaches. In our study, we focused on the application of laser-based spectroscopy in skin cancer...

Immunohistochemistry (IHC) and immunocytochemistry (ICC) are widely used to identify cancerous cells within tissues and cell cultures. Even though the optical microscopy evaluation is considered the gold standard, the limited range of useful labels and narrow multiplexing capabilities create an imminent need for alternative readout techniques. Lase...

Emission spectra yielded by laser-induced breakdown spectroscopy (LIBS) exhibit high dimensionality, redundancy, and sparsity. The high dimensionality is often addressed by principal component analysis (PCA) which creates a low dimensional embedding of the spectra by projecting them into the score space. However, PCA does not effectively deal with...

Alagille syndrome (ALGS) is generally thought of as a pediatric cholestatic liver disease, but spontaneous bleeds are a major cause of death. Here, we investigated bleeding in patients and a mouse model for ALGS (Jag1Ndr/Ndr mice) and asked whether phenotypes identified in mice could be detected in patients non-invasively. Jag1Ndr/Ndr mice spontane...

The main goal of this study was to assess the progress of vertebral stability after lumbar interbody fusion related to microcomputed tomography (micro CT), biomechanical analysis, and histological assessment towards spine fusion. Twelve male pigs were used; each underwent L2-3 discectomy and implantation of an iliac crest bone graft in two groups;...

Background X-ray microtomography (μCT) has become an invaluable tool for non-destructive analysis of biological samples in the field of developmental biology. Mouse embryos are a typical model for investigation of human developmental diseases. By obtaining 3D high-resolution scans of the mouse embryo heads, we gain valuable morphological informatio...

Aims The aim of this study was to answer the question whether our newly developed injectable biodegradable “self-setting” polymer-composite as a bone adhesive is a good “bone-glue” candidate to efficiently fix comminuted fractures of pig femoral bones used as an ex-vivo experimental model. Methods Mechanical properties of adhesive prepared from α-...

Purpose This paper aims to focus on the evaluation of a polymer concrete as a three-dimensional (3D) printing material. An associated company has developed plastic concrete made from reused unrecyclable plastic waste. Its intended use is as a construction material. Design/methodology/approach The concrete mix, called PolyBet, composed of polypropy...