Effect of screw angulation and multiple insertions on load-to-failure of polyaxial locking system.

PURPOSE: Polyaxial locking plates rely on the alignment between the thread-to-thread connections of the screw head and the plate hole. These implants have provided substantial support for surgeons. In particular, extended screw positioning have proven to be beneficial in the fixation of challenging fractures. This study aimed to investigate the mechanical properties of ChM 5.0 ChLP polyaxial screws inserted in off-axis trajectories, including multiple insertions and to correlate these parameters with the screw head and the plate hole thread-to-thread engagement. METHODS: Polyaxial locking screws were inserted into the plates at various angles (0°,10°,15°, -15° off-axis). Multiple time inserted screws were placed firstly at 15°, then 0° and finally -15° off-axis in the same plate hole. A microCT scan of the plate-hole and screw-head interface was conducted before destructive tests. Representative screws from each group were also examined by Scanning Electron Microscope. RESULTS: The standard insertion at 0° sustained the greatest maximum bending strength without relocation in the screw hole. Screws inserted at 10° and 15° (one time) showed a significant reduction in load-to-failure of up to 36% and 55%, (p = 0.001) (p = 0.001) respectively. Screws inserted at -15° after a maximum of three multiple insertions with angle shift, showed a total reduction in force of up to 70% (p = 0.001). A microCT analysis of thread engagement showed significant correlations. However, the results obtained for multiple insertions were highly variable. CONCLUSIONS: ChM 5.0 ChLP polyaxial locking system has valuable properties that foster fracture fixation, providing various surgical options. Nevertheless, the freedom of off-axis placement and multiple insertions of the screws comes at the price of reduced force. When possible surgeons should minimize the angles of insertions.

Effect of screw angulation on the bending performance of polyaxial locking interfaces: a micro-CT evaluation.

Polyaxial locking plates rely on a specific thread-to-thread interface of the screw head and the plate hole. The objective of this study was to evaluate the mechanical performance of single screw interfaces when inserted off-axis and to establish correlations between those parameters and the engagement of the screw head and the plate hole thread. Three polyaxial locking screw systems were inserted into the corresponding plates at various angles (0°, 5°, 10°, and 15° off-axis). The screws were tested until failure. A micro-CT was performed to examine the interface between the plate hole and the screw head. The standard insertion at 0° sustained the greatest maximum bending strength without relocation in the screw hole. Screws inserted at 15° showed a significant reduction in force of up to 44%, 55% and 57%, respectively. Micro-CT analysis of the interface showed a significant loss of thread engagement for off-axis insertion. Polyaxial plates offer additional advantages for off-axis placement of screws. However, this flexibility is related to a significant decrease in both thread engagement and bending strength compared to monoaxial insertion. Regardless the insertion angle, the loss of stability is comparable when screws are placed off-axis. Surgeons are advised to consider off-axis insertion as a salvage option, providing access to better bone stock.

SARS-CoV-2 infection activating a novel variant of the NOTCH3 gene and subsequently causing development of CADASIL.

Introduction: In the following study we describe the diagnostic process and further case analysis of a 30-year-old woman admitted with typical COVID-19 symptoms, who subsequently developed additional symptoms suggesting cerebral autosomal dominant arteriopathy with sub-cortical infarcts and leukoencephalopathy (CADASIL). Material and methods: Other than the standard diagnostic procedures, whole genome sequencing (WGS) was used, which led to following findings. A new variant of the NOTCH3 gene, which led to CADASIL-like symptoms, was found, and it had been most likely activated by the SARS-CoV-2 infection. This novel variant in NOTCH3 has not been found in existing databases and has never been mentioned in research concerning CADASIL before. Results: Furthermore, after subjecting the patient's close relatives to WGS it was found that no other examined person demonstrated the same genetic mutation. Conclusions: It seems therefore that the new variant of NOTCH3 is of de novo origin in the patient's genome. Additionally, the relatively early onset of CADASIL and the unexpectedly severe COVID-19 infection suggest that the two occurred simultaneously: the infection with SARS-CoV-2 accelerated development of CADASIL symptoms and the unusual variant of the NOTCH3 gene contributed to the more severe course of COVID-19.

Biomechanical evaluation of variable angle locking systems. A micro-CT analysis.

PURPOSE: Formerly poor bone stock and periprosthetic fractures used to jeopardize monaxial constructs. Polyaxial locking screws have substantially supported those particular fixation constructs. However, those systems rely on complex alignment between the screw head and the plate hole. This study aimed to investigate the mechanical properties of several polyaxial systems and to correlate these parameters with the screw head and the plate hole engagement. METHODS: Polyaxial locking systems were tested with screws inserted into the corresponding plates at various angles (0°, 5°, 10°, 15°). A micro-CT scan of the plate-hole and screw-head interface with the quantification of average thread engagement was performed before destructive tests. The screw-plate interface of each system was tested in a cantilever bending setup. Representative screws and plates were also examined by SEM. RESULTS: The standard insertion at 0° sustained the greatest maximum bending strength in all analyzed systems. Point-loading thread-in and cut-in screws inserted off-axis showed a significant reduction in bending strength (p<0.001) (p=0.041) (p<0.001). In contrast, locking cap screws maintained similar bending strength with disregard to the angle of insertion (p<0.4849). A micro-CT analysis confirmed that the average thread engagement of point-loading thread-in, cut-in and locking-cap screws was significantly reduced when placed off-axis (p=0.005) (p<0.001) (p=0.002) (p<0.001). The locking-cap mechanisms maintained the highest average thread engagement among all analyzed systems. CONCLUSIONS: The mechanical performance of polyaxial locking plates usually comes at the price of reduced bending strength. Surgeons should limit polyaxial insertions depending on the particular system's characteristics.

Influence of Dispersed Phase Content on the Mechanical Properties of Electroless Nanocomposite Ni-P/Si3N4 and Hybrid Ni-P/Si3N4/Graphite Layers Deposited on the AW-7075 Alloy.

The article presents the results of mechanical testing of Ni-P/Si3N4 nanocomposite and hybrid Ni-P/Si3N4/graphite coatings deposited on AW-7075 aluminum alloy using the chemical reduction method. In terms of mechanical testing, microhardness was measured, and surface roughness and adhesion of the coatings to the aluminum substrate were determined using the "scratch test" method. The surface morphology of the deposited layers was also analyzed using light microscopy and scanning electron microscopy. Samples made of AW-7075 aluminum alloy with electroless deposited Ni-P/Si3N4 nanocomposite, Ni-P/graphite composite and hybrid Ni-P/Si3N4/graphite coatings with different content of dispersed phases were tested, and also, for comparison purposes, the Ni-P layer that constituted the matrix of the tested materials. Reinforcing phases in the form of silicon nitride nanoparticles and graphite particles were used in the layers. The purpose of the research was a thorough characterization of the coating materials used on aluminum alloys in terms of mechanical properties. Graphite is considered in this paper as it enables the reduction of the coefficient of friction through its lubricating properties. Unfortunately, graphite is difficult to use in selected layers as the only dispersion phase, because it has much lower hardness than the Ni-P coating. For this reason, a layer with a single dispersion phase in the form of graphite will be characterized by worse mechanical properties. It is necessary to add particles or nanoparticles with hardness higher than the base Ni-P coating, e.g., Si3N4, which improve the mechanical properties of the coating. The presented analyses of the results of the conducted research complement the previous studies on selected properties of nanocomposite layers with an amorphous structure and supplement the knowledge regarding their suitability for application to aluminum machine parts.

State of the Art in Temporomandibular Joint Arthrocentesis-A Systematic Review.

Temporomandibular joint disorders are a heterogenic group of clinical conditions, which impair physiological functioning of the masticatory system. Arthrocentesis of the temporomandibular joint has become a widely approved method for non-invasive treatment, bridging the gap between conservative and surgical approaches. Regardless of technique, treatment is based upon joint lavage and lysis of the inflammatory fibrous tissue adhesions, which, in turn, improves joint mobility and reduces pain and closed lock. Recently, approaches for intra-articular injections have been proposed as adjuvant or replacement therapy. The aim of this study was to assess the most efficient technique of arthrocentesis. A systematic search based on PRISMA guidelines, including a computer search with specific keywords, a reference list search and a manual search, was performed. Relevant articles were selected after three search rounds for final review. The studies pulled for the analysis presented information about the relevant predictors, including the technique of arthrocentesis (single- or two-needle method), fluid used for lavage (Ringer lactate or saline), volume of the fluid, application of the injectable, number of interventions, pain (VAS) and mouth opening scores (MMO) and follow-up. All cohorts showed improvement in mouth opening, but significant pain reduction was observed only in cohorts treated either by arthrocentesis alone or arthrocentesis followed by intra-articular injectables. Intra-articular injectables used alone failed to reduce pain post-operatively when compared to other cohorts. We concluded that both double-needle and single-puncture arthrocentesis techniques are equally efficient. Application of the adjuvant injectable did not improve the outcomes of arthrocentesis performed alone. The volume of the fluid used for joint lavage and its chemical composition were not significant in clinical outcomes. However, due to the lack of homogeneity in the study settings, a meta-analysis could not be applied and a systematic review was conducted. We still, however, state that there is a knowledge gap in the current literature regarding the use of injectables alone, as well as a longitudinal follow-up, which provides information about treatment efficiency. More high-quality and randomized controlled trials are required to shed light on this subject.

Successive Acanthamoeba Corneal Isolates Identified in Poland Monitored in Terms of In Vitro Dynamics.

BACKGROUND: Amoebae of the genus Acanthamoeba cause a sight-threatening infection called Acanthamoeba keratitis. It is considered a rare disease in humans but poses an increasing threat to public health worldwide, including in Poland. We present successive isolates from serious keratitis preliminary examined in terms of the identification and monitoring of, among others, the in vitro dynamics of the detected strains. METHODS: Clinical and combined laboratory methods were applied; causative agents of the keratitis were identified at the cellular and molecular levels; isolates were cultivated in an axenic liquid medium and regularly monitored. RESULTS: In a phase-contrast microscope, Acanthamoeba sp. cysts and live trophozoites from corneal samples and in vitro cultures were assessed on the cellular level. Some isolates that were tested at the molecular level were found to correspond to A. mauritanensis, A. culbertsoni, A. castellanii, genotype T4. There was variability in the amoebic strain dynamics; high viability was expressed as trofozoites' long duration ability to intense multiply. CONCLUSIONS: Some strains from keratitis under diagnosis verification and dynamics assessment showed enough adaptive capability to grow in an axenic medium, allowing them to exhibit significant thermal tolerance. In vitro monitoring that was suitable for verifying in vivo examinations, in particular, was useful to detect the strong viability and pathogenic potential of successive Acanthamoeba strains with a long duration of high dynamics.

The Influence of Osteon Orientation on Surface Topography Parameters after Machining of Cortical Bone Tissue.

Mechanical processing of cortical bone tissue is one of the most common surgical procedures. A critical issue accompanying this processing is the condition of the surface layer, which can stimulate tissue growth and serve as a drug carrier. A comparison of the surface condition before and after orthogonal and abrasive processing was conducted to validate the influence of bone tissue's processing mechanism and orthotropic properties on the surface topography. A cutting tool with a defined geometry and a custom-made abrasive tool was used. The bone samples were cut in three directions, depending on the orientation of the osteons. The cutting forces, acoustic emission, and surface topography were measured. The level of isotropy and the topography of the grooves showed statistical differences relative to the anisotropy directions. After orthogonal processing, the surface topography parameter Ra was determined from 1.38 ± 0.17 µm to 2.82 ± 0.32. In the case of abrasive processing, no correlation was found between the orientation of osteons and topographical properties. The average groove density for abrasive machining was below 1004 ± 0.7, and for orthogonal, it was above 1156 ± 58. Due to the positive properties of the developed bone surface, it is advisable to cut in the transverse direction and parallel to the axis of the osteons.

The cancer-risk variant frequency among Polish population reported by the first national whole-genome sequencing study.

Introduction: Population-based cancer screening has raised many controversies in recent years, not only regarding the costs but also regarding the ethical nature and issues related to variant interpretation. Nowadays, genetic cancer screening standards are different in every country and usually encompass only individuals with a personal or family history of relevant cancer. Methods: Here we performed a broad genetic screening for cancer-related rare germline variants on population data from the Thousand Polish Genomes database based on 1076 Polish unrelated individuals that underwent whole genome sequencing (WGS). Results: We identified 19 551 rare variants in 806 genes related to oncological diseases, among them 89% have been located in non-coding regions. The combined BRCA1/BRCA2 pathogenic/likely pathogenic according to ClinVar allele frequency in the unselected population of 1076 Poles was 0.42%, corresponding to nine carriers. Discussion: Altogether, on the population level, we found especially problematic the assessment of the pathogenicity of variants and the relation of ACMG guidelines to the population frequency. Some of the variants may be overinterpreted as disease-causing due to their rarity or lack of annotation in the databases. On the other hand, some relevant variants may have been overseen given that there is little pooled population whole genome data on oncology. Before population WGS screening will become a standard, further studies are needed to assess the frequency of the variants suspected to be pathogenic on the population level and with reporting of likely benign variants.

Influence of Machining Parameters on Cutting and Chip-Formation Process during Cortical Bone Orthogonal Machining.

Cortical bone machining is commonly used in craniofacial surgery. The shaping of bone surfaces requires a precise determination of the process's complexity due to the cutting tool's defined or undefined geometry. Therefore, research was carried out to assess the impact of the rake angle (γ), clearance angle and depth of cut (d) on the cortical bone machining process. Analysis was carried out based on the orthogonal cutting in three directions. The cutting tool shape was simplified, and the cutting forces and the chip-formation process were monitored. The highest values of the resultant cutting force and shear force were recorded for γ < 0. The specific cutting force decreases with the increase of d. Cutting in the transverse direction is characterized by the highest values of resultant cutting force and shear force. The coefficient of friction depends primarily on the d and takes a constant value or increases with the increase of γ. The tests showed that the chips are formed in the entire range of d ≥ 0.5 µm and create regular shapes for d ≥ 10 µm. The research novelty confirms that even negative cutting angles guarantee controlled cutting and can find wider application in surgical procedures.

Bone Abrasive Machining: Influence of Tool Geometry and Cortical Bone Anisotropic Structure on Crack Propagation.

The abrasive machining of cortical tissue is used in many arthroplasties and craniofacial surgery procedures. However, this method requires further research due to the processes' complexity and the tissue's composite structure. Therefore, studies were carried out to assess the impact of grid geometry and the anisotropic structure of bone tissue on the cutting process and crack propagation. The analysis was performed based on an orthogonal cutting in three directions. The grain shape has been simplified, and the cutting forces, crack path and surface quality were monitored. The results indicate that a depth of cut at 100−25 µm allows the most accurate cutting control. A transverse cutting direction results in the greatest surface irregularity: Iz = 17.7%, Vvc = 3.29 mL/m2 and df = 5.22 µm and generates the most uncontrolled cracks. Maximum fracture force values of FF > 80 N were generated for d = 175 µm. For d < 5 µm, no cracks or only slight penetration occurs. A positive γ provides greater repeatability and crack control. Negative γ generates penetrating cracks and uncontrolled material damage. The individual types of cracks have a characteristic course of changes in Fx. The clearance angle did not affect the crack propagation.

Gene Variants Related to Cardiovascular and Pulmonary Diseases May Correlate with Severe Outcome of COVID-19.

Background: Severe outcomes of COVID-19 account for up to 15% of all cases. The study aims to check if any gene variants related to cardiovascular (CVD) and pulmonary diseases (PD) are correlated with a severe outcome of COVID-19 in a Polish cohort of COVID-19 patients. Methods: In this study, a subset of 747 samples from unrelated individuals collected across Poland in 2020 and 2021 was used and whole-genome sequencing was performed. Results: The GWAS analysis of SNPs and short indels located in genes related to CVD identified one variant significant in COVID-19 severe outcome in the HADHA gene, while for the PD gene panel, we found two significant variants in the DRC1 gene. In this study, both potentially protective and risk variants were identified, of which variants in the HADHA gene deserve the most attention. Conclusions: This is the first study reporting the association between the HADHA and DRC1 genetic variants and COVID-19 severe outcome based on the cohort WGS analysis. Although all the identified variants are localised in introns, they may be correlated and therefore inherited along with other risk variants, potentially causative to severe outcome of COVID-19 but not discovered yet.

DBFE: distribution-based feature extraction from structural variants in whole-genome data.

MOTIVATION: Whole-genome sequencing has revolutionized biosciences by providing tools for constructing complete DNA sequences of individuals. With entire genomes at hand, scientists can pinpoint DNA fragments responsible for oncogenesis and predict patient responses to cancer treatments. Machine learning plays a paramount role in this process. However, the sheer volume of whole-genome data makes it difficult to encode the characteristics of genomic variants as features for learning algorithms. RESULTS: In this article, we propose three feature extraction methods that facilitate classifier learning from sets of genomic variants. The core contributions of this work include: (i) strategies for determining features using variant length binning, clustering and density estimation; (ii) a programing library for automating distribution-based feature extraction in machine learning pipelines. The proposed methods have been validated on five real-world datasets using four different classification algorithms and a clustering approach. Experiments on genomes of 219 ovarian, 61 lung and 929 breast cancer patients show that the proposed approaches automatically identify genomic biomarkers associated with cancer subtypes and clinical response to oncological treatment. Finally, we show that the extracted features can be used alongside unsupervised learning methods to analyze genomic samples. AVAILABILITY AND IMPLEMENTATION: The source code of the presented algorithms and reproducible experimental scripts are available on Github at https://github.com/MNMdiagnostics/dbfe. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Influence of Exposure Parameters and Implant Position in Peri-Implant Bone Assessment in CBCT Images: An In Vitro Study.

The aim of this study was to assess the impact of dimensional distortion and its changes with modification of exposure setting parameters on the measurements of peri-implant bone margin. Ten titanium dental implants (InKone Primo, Global D, Paris, France) were placed in two prepared bovine ribs. Two bone models and an implant-with-transfer model were scanned with 3shape E4 (3shape, Copenhagen, Denmark) laboratory scanner. Cone beam computed tomography (CBCT) images of two bone models were taken with different values of voltage (60, 70, 80, 90 kV), tube current (4, 10 mA) and voxel size (200, 300 µm). All the data were superimposed using planning software, and the measurements of buccal bone thickness in two selected regions were performed both using CBCT and scan cross-sections. The mean squared error (MSE) being the squared differences between measurements was used in the accuracy assessment of the CBCT device. A one-way ANOVA revealed significant differences between voltage and MSE (p = 0.044), as well as implant position and MSE (p = 0.005). The distortions of measurements depend on bone margin thickness, and the higher the distance to measure, the higher the error. Accurate measurements of buccal bone thickness (MSE below 0.25) were achieved with voltage values of 70, 80, and 90 kV.

What Is the Cost of Off-Axis Insertion of Locking Screws? A Biomechanical Comparison of a 3.5 mm Fixed-Angle and 3.5 mm Variable-Angle Stainless Steel Locking Plate Systems.

OBJECTIVE: The aim of this study was to evaluate the effect of screw insertion angle and insertion torque on the mechanical properties of a 3.5 fixed-angle locking plate locking compression plate (LCP) and 3.5 variable-angle locking plate polyaxial locking system (PLS). METHODS: In the LCP group, screws were placed abaxially at 0, 5 and 10 degrees. In the PLS group, screws were placed at 0, 5, 10, 15 and 20 degrees abaxially. The insertion torque was set to 1.5 and 2.5 Nm in the LCP and PLS groups respectively. A load was applied parallel to the screw axis, and the screw push-out force was measured until the locking mechanism was loosened. RESULTS: The 3.5 LCP showed higher push-out strength than the 3.5 PLS when the screws were placed at 0 degree regardless of the insertion torque. The off-axis insertion of 3.5 LCP locking screws resulted in a significant decrease in push-out strength (p < 0.05). A higher insertion torque value significantly increased the screw holding strength for the 3.5 LCP (p < 0.05). The 3.5 PLS system had a significantly higher push-out force when the screws are at 0 degree than at 5, 10 and 15 degrees, and 20 degrees (p < 0.05) at any given insertion torque. An increase in the insertion torque did not have a significant effect on the push-out strength of the 3.5 PLS locking system. CONCLUSION: The 3.5 PLS is more sensitive to the screw insertion angle than to the insertion torque, whereas the 3.5 LCP is affected by both factors. Placing 3.5 LCP locking screws off-axis significantly reduces the screw holding strength; therefore, this approach has to be avoided. The findings of our research indicate that a 1.5 Nm torque can be used for a 3.5 PLS.

The Thousand Polish Genomes-A Database of Polish Variant Allele Frequencies.

Although Slavic populations account for over 4.5% of world inhabitants, no centralised, open-source reference database of genetic variation of any Slavic population exists to date. Such data are crucial for clinical genetics, biomedical research, as well as archeological and historical studies. The Polish population, which is homogenous and sedentary in its nature but influenced by many migrations of the past, is unique and could serve as a genetic reference for the Slavic nations. In this study, we analysed whole genomes of 1222 Poles to identify and genotype a wide spectrum of genomic variation, such as small and structural variants, runs of homozygosity, mitochondrial haplogroups, and de novo variants. Common variant analyses showed that the Polish cohort is highly homogenous and shares ancestry with other European populations. In rare variant analyses, we identified 32 autosomal-recessive genes with significantly different frequencies of pathogenic alleles in the Polish population as compared to the non-Finish Europeans, including C2, TGM5, NUP93, C19orf12, and PROP1. The allele frequencies for small and structural variants, calculated for 1076 unrelated individuals, are released publicly as The Thousand Polish Genomes database, and will contribute to the worldwide genomic resources available to researchers and clinicians.

The Impact of Cone-Beam Computed Tomography Exposure Parameters on Peri-Implant Artifacts: A Literature Review.

Cone-beam computed tomography (CBCT) amounts to an excellent diagnostic tool to evaluate the peri-implant bone thickness in all dimensions. Despite the unquestionable advantages of CBCT, potential artifacts around dental implants might disturb the proper assessment of the surrounding structures. The artifacts may mask osseointegration, shallow bone defects, and other types of radiolucency, which make it difficult to establish an early diagnosis of bone loss. Proper diagnosis of bone defect is necessary to decide about surgical intervention. The aim of this literature review is to assess the CBCT exposure causing artifacts on the peri-implant structures. An electronic search of MEDLINE (PubMed) database includes studies published before July 2021 and supplemented by manual research. Clinical, ex vivo, in vitro, and animal studies evaluating the relationship between exposition parameters and occurrence of artifacts around the dental implant in CBCT studies were included. A literature review revealed that kilovoltage, tube current, and field of view may affect the occurrence of artifacts around dental implants, all of which would compromise radiological evaluation. Therefore, it is feasible to reduce the incidence of artifacts and improve the image quality by appropriate modification of the exposure parameters. However, the reduction of artifacts is often associated with a significant increase in radiation exposure; hence, an effort should be made to minimize the radiation dose in line with the ALARA (as low as reasonably achievable) principle.

Validation of HER2 Status in Whole Genome Sequencing Data of Breast Cancers with the Ploidy-Corrected Copy Number Approach.

BACKGROUND AND OBJECTIVE: Human epidermal growth factor receptor 2 (HER2) protein overexpression is one of the most significant biomarkers for breast cancer diagnostics, treatment prediction, and prognostics. The high accessibility of HER2 inhibitors in routine clinical practice directly translates into the diagnostic need for precise and robust marker identification. Even though multigene next-generation sequencing methodologies have slowly taken over the field of single-biomarker molecular tests, the copy number alterations such as amplification of the HER2-coding ERBB2 gene are hard to validate on next-generation sequencing platforms as they are characterized by chromosomal structural heterogeneity, polysomy, and genomic context of ploidy. In our study, we tested the approach of using whole genome sequencing instead of next-generation sequencing panels to determine HER2 status in the clinical set-up. METHODS: We used a large dataset of 876 patients with breast cancer whole genomes with curated clinical data and an additional set of 551 patients' external genomic data. We used the decision-tree-based algorithm for optimization of the diagnostic tool for HER2 status assessment by whole genome sequencing. RESULTS: The most efficient approach to assess HER2 status in whole genome sequencing data was the ploidy-corrected copy number, utilizing ERBB2 copy number and mean tumor ploidy. The classifier achieved sensitivity of 91.18% and specificity of 98.69% on the internal validation dataset and 89.86% and 96.06% on the external data, which is similar to other next-generation sequencing methods, currently tested in the clinic. CONCLUSIONS: We provide evidence that the HER2 status may be reliably determined by whole genome sequencing and is applicable across different laboratory protocols and pipelines. We suggest using the ploidy-corrected copy number for diagnostic purposes.

Methodology for preparing a cosmetic sample for the development of Microorganism Detection System (SDM) software and artificial intelligence learning to recognize specific microbial species.

INTRODUCTION AND OBJECTIVE: The article presents the methodology of preparing a cosmetic sample for analysi, and the creation of a dataset for teaching artificial intelligence to recognize specific species of microorganisms in cosmetic samples in terms of compliance with the ISO standard document, to develop of the Microorganism Detection System (SDM). MATERIAL AND METHODS: Methodology of preparation a cosmetic sample for testing covers the steps from taking a cosmetic sample to obtaining separated living microorganisms through staining to photos, which in the final stage are used for analysis of the purity of cosmetics by SDM, as well as for learning and testing of the deep convolutional neural network (CNN) for detecting and classifying cells of specific species of bacteria, fungi and yeast in cosmetics, according to the document of standard PN-EN ISO 17516-2014:11. RESULTS: A new techique was devised for preparing a cosmetic sample for the development of Microorganism Detection System (SDM) software, and artificial intelligence learning to recognize specific microbial species. Based on metod demonstrated, the Intelligent algorithms of SDM proved to be effective in counting and recognizing specific microorganisms (average accuracy for Candida albicans - 97%, Escherichia coli - 76%, Pseudomonas aeruginosa - 70%, Staphylococcus aureus - 85%), which are the most important species for the assessment of the purity of cosmetics. In addition, the reproducibility of the developed method was verified, and the results obtained were comparable to the breeding methods currently used, based on specific standards. CONCLUSIONS: The experiments confirmed the high sensitivity and specificity of the SDM method, its repeatability and, above all, the comparability of the results with clasic methods of European standards.

The Microorganism Detection System (SDM) for microbiological control of cosmetic products.

The Microorganism Detection System (SDM) is a new solution using artificial intelligence, unique on the international scale, to correctly identify and count microorganisms, with particular emphasis on specificlisted microorganisms (Document of Standard PN-EN ISO 17516-2014:11) - Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus. SDM enables the use of algorithms for microscopic image interpretation in the microbiological assessment of the cosmetics in accordance with the standard, providing an answer to whether the tested product complies with the standard. Apart from the software part of SDM, an integral part of the system is an innovative methodology for preparing a cosmetic sample for testing. The experiments confirm the high sensitivity and specificity of the SDM method, its repeatability and, above all, the comparability of the results with the methods of European standards.