Healthy Conditions Research Articles

Prediction of air compressor faults with feature fusion and machine learning

Air compressors are critical for many industries, but early detection of faults is crucial for keeping them running smoothly and minimizing maintenance costs. This contribution investigates the use of predictive machine learning models and feature fusion to diagnose faults in single-acting, single-stage reciprocating air compressors. Vibration signals acquired under healthy and different faulty conditions (inlet valve fluttering, outlet valve fluttering, inlet-outlet valve fluttering, and check valve fault) serve as the study’s input data. Diverse features including statistical attributes, histogram data, and auto-regressive moving average (ARMA) coefficients are extracted from the vibration signals. To identify the most relevant features, the J48 decision tree algorithm is employed. Five lazy classifiers viz. k-nearest neighbor (kNN), K-star, local kNN, locally weighted learning (LWL), and random subspace ensemble K-nearest neighbors (RseslibKnn) are then used for fault classification, each applied to the individual feature sets. The classifiers achieve commendable accuracy, ranging from 85.33% (K-star and local kNN) to 96.00% (RseslibKnn) for individual features. However, the true innovation lies in feature fusion. Combining the three feature types, statistical, histogram, and ARMA, significantly improves accuracy. When local kNN is used with fused features, the model achieves a remarkable 100% classification accuracy, demonstrating the effectiveness of this approach for reliable fault diagnosis in air compressors.

Meta-analysis of oral microbiome reveals sex-based diversity in biofilms during periodontitis.

Sex is an often overlooked, yet compulsory, biological variable when performing biomedical research. Periodontitis is a common yet progressively debilitating chronic inflammatory disorder affecting the tissues supporting teeth that ultimately leads to tooth loss if left untreated. The incidence of periodontitis is sex biased, with increased prevalence in males compared with females but with unknown etiology. We performed a sex-specific meta-analysis using publicly available oral microbiome data from different sampling sites of patients with periodontitis and periodontally healthy controls; sex balance was established for each periodontal health condition. Our results show sex-based diversity in oral biofilms of individuals with periodontitis but not in their saliva, with increased abundance of several periodontal pathogens in subgingival plaques from females compared with males. We devised a quantitative measure, uniquely defined as the Microsexome Index (MSI), which indicates that sexual dimorphism in subgingival bacterial composition is a distinct feature of reduced microbial diversity during periodontitis but not under healthy conditions. In addition, we found that smoking exacerbates microsexome diversity in supragingival biofilms, particularly during periodontitis. Taken together, we provide insights regarding sex-based diversity in periodontitis, a disease with multiorgan associations, and provide the rationale for further mechanistic, diagnostic, and therapeutic studies.

Influence of Temperature on Brushless Synchronous Machine Field Winding Interturn Fault Severity Estimation

There are numerous methods for detecting interturn faults (ITFs) in the field winding of synchronous machines (SMs). One effective approach is based on comparing theoretical and measured excitation currents. This method is unaffected by rotor temperature in static excitation SMs. However, this paper investigates the influence of rotor temperature in brushless synchronous machines (BSMs), where rotor temperature significantly impacts the exciter excitation current. Extensive experimental tests were conducted on a special BSM with measurable rotor temperature. Given the challenges of measuring rotor temperature in industrial machines, this paper explores the feasibility of using stator temperature in the exciter field current estimation model. The theoretical exciter field current is calculated using a deep neural network (DNN), which incorporates electrical brushless synchronous generator output values and stator temperature, and it is subsequently compared with the measured exciter field current. This method achieves an error rate below 0.5% under healthy conditions, demonstrating its potential for simple implementation in industrial BSMs for ITF detection.

Orally Ingested Micro- and Nano-Plastics: A Hidden Driver of Inflammatory Bowel Disease and Colorectal Cancer.

Micro- and nano-plastics (MNPLs) can move along the food chain to higher-level organisms including humans. Three significant routes for MNPLs have been reported: ingestion, inhalation, and dermal contact. Accumulating evidence supports the intestinal toxicity of ingested MNPLs and their role as drivers for increased incidence of colorectal cancer (CRC) in high-risk populations such as inflammatory bowel disease (IBD) patients. However, the mechanisms are largely unknown. In this review, by using the leading scientific publication databases (Web of Science, Google Scholar, Scopus, PubMed, and ScienceDirect), we explored the possible effects and related mechanisms of MNPL exposure on the gut epithelium in healthy conditions and IBD patients. The summarized evidence supports the idea that oral MNPL exposure may contribute to intestinal epithelial damage, thus promoting and sustaining the chronic development of intestinal inflammation, mainly in high-risk populations such as IBD patients. Colonic mucus layer disruption may further facilitate MNPL passage into the bloodstream, thus contributing to the toxic effects of MNPLs on different organ systems and platelet activation, which may, in turn, contribute to the chronic development of inflammation and CRC development. Further exploration of this threat to human health is warranted to reduce potential adverse effects and CRC risk.

The Ubiquitin Tale: Current Strategies and Future Challenges.

Ubiquitin (Ub) is often considered a structurally conserved protein. Ubiquitination plays a prominent role in the regulation of physiological pathways. Since the first mention of Ub in protein degradation pathways, a plethora of nonproteolytic functions of this post-translational modification have been identified and investigated in detail. In addition, several other structurally and functionally related proteins have been identified and investigated for their Ub-like structures and functions. Ubiquitination and Ub-like modifications play vital roles in modulating the pathways involved in crucial biological processes and thus affect the global proteome. In this Review, we provide a snapshot of pathways, substrates, diseases, and novel therapeutic targets that are associated with ubiquitination or Ub-like modifications. In the past few years, a large number of proteomic studies have identified pools of ubiquitinated proteins (ubiquitylomes) involved or induced in healthy or stressed conditions. These comprehensive studies involving identification of new ubiquitination substrates and sites contribute enormously to our understanding of ubiquitination in more depth. However, with the current tools, there are certain limitations that need to be addressed. We review recent technological advancements in ubiquitylomic studies and their limitations and challenges. Overall, large-scale ubiquitylomic studies contribute toward understanding global ubiquitination in the contexts of normal and disease conditions.

Fibrin Scaffolds Perfused with Transforming Growth Factor-β1 as an In Vitro Model to Study Healthy and Tendinopathic Human Tendon Stem/Progenitor Cells.

A limited understanding of tendon cell biology in healthy and pathological conditions has impeded the development of effective treatments, necessitating in vitro biomimetic models for studying tendon events. We established a dynamic culture using fibrin scaffolds, bioengineered with tendon stem/progenitor cells (hTSPCs) from healthy or diseased human biopsies and perfused with 20 ng/mL of human transforming growth factor-β1 for 21 days. Both cell types showed long-term viability and upregulated Scleraxis (SCX-A) and Tenomodulin (TNMD) gene expressions, indicating tenogenic activity. However, diseased hTSPCs underexpressed collagen type I and III (COL1A1 and COL3A1) genes and exhibited lower SCX-A and TNMD protein levels, but increased type I collagen production, with a type I/type III collagen ratio > 1.5 by day 14, matching healthy cells. Diseased hTSPCs also showed constant high levels of pro-inflammatory cytokines, such as IL-8 and IL-6. This biomimetic environment is a valuable tool for studying tenogenic and inflammatory events in healthy and diseased tendon cells and identifying new therapeutic targets.

Abstract P451: Effects of Perivascular Adipose Tissue on Arterial Stiffness in an Adiposity-Driven Hypertension Model: A Longitudinal Study

Perivascular adipose tissue (PVAT) is crucial for maintaining arterial function under healthy conditions. This research aims to test the hypothesis that the effect of PVAT on arterial stiffness is lessened as hypertension progresses in an animal model of adiposity-driven hypertension. We examined thoracic aorta samples from male Dahl Salt-Sensitive rats subjected to control (10% fat-CD) and high-fat (60% fat-HFD) diets for 16 and 24 weeks. Systolic blood pressure was significantly higher in HFD rats only at 24 weeks as compared to CD. Uniaxial mechanical tests were then conducted on aorta samples with and without PVAT. Arterial wall stiffness at 20% stretch (matching in vivo measures) was increased but not significantly higher in animals fed a HFD compared to those on a CD at 16 weeks but not 24 weeks. Surprisingly, the calculated stiffness of -PVAT samples significantly decreased by 24 weeks in both groups. Stiffness was reduced at both time points in +PVAT samples compared to -PVAT, but the beneficial effect of PVAT is diminished at 24 weeks. Because lower stretches may be important as hypertension progresses. We also measured stiffness at stretches <10%. Here, the addition of PVAT lost all beneficial effects on stiffness at 24 weeks. These results suggest that while PVAT has a beneficial effect on arterial stiffness in adiposity-driven hypertension, its effectiveness decreases with aging.

Comorbidity, Eating Behaviors and Smartphone Addiction in Italian Nurses' Characteristics.

Evidence suggested how nurses experienced worse lifestyles than the general population by recording deterioration rates in healthy conditions. To assess differences between comorbidity, eating behavior, and smartphone addiction according to sex, Body Mass Index (BMI), age, work experience, shift, alcohol assumption, and physical activity in Italian nurses. An online questionnaire was spread through some professional internet pages. Data included demographic characteristics, the Charlson Comorbidity Index (CCI), the Italian Version of the Dutch Eating Behavior Questionnaire, and the Smartphone Addiction Scale (SAS-SV). A total of 456 nurses were recruited. Significant differences were registered in the smartphone addiction score (p=0.030) and BMI scores and work experience (p=0.001), as underweight participants reported higher scores in the smartphone addiction attitude (2.4714 ± 1.25812) than the other subjects and also participants with the highest number of years in work experience also reported higher smartphone addiction scores (2.8074 ± 1.2022). Significant difference was reported in the CCI scores according to age (p<0.001): subjects aged over 61 years recorded higher scores in the CCI (1.67 ± 1.528) and also according to work experience and CCI scores (p<0.001), as participants employed between 21 and 30 years reported higher scores in the CCI (1.27 ± 1.382) and also to night shift (p=0.037), as participants who worked during the night shift also reported higher scores in the CCI. A significant difference was reported only for restrained eating attitude (p=0.034), as participants who declared to assume alcohol 2-3 times per month recorded higher levels in this eating attitude aspect (32.32 ± 7.181). Female nurses, overweight and obese nurses with low physical activity practice, seemed to spend more time with their smartphones. Healthcare organizations should consider findings to prevent unhealthy lifestyles among nurses, which could negatively influence the whole healthcare system.

Performance of a Dual Three-Phase Permanent Magnet Machine for a Steer-By-Wire System Under Healthy and Faulty Conditions

Performance of a Dual Three-Phase Permanent Magnet Machine for a Steer-By-Wire System Under Healthy and Faulty Conditions

Characteristics of clinical manifestation of acute haematogenous osteomyelitis of the bones of the hip joint in children

Aim. To study the characteristics of the clinical manifestations of acute haematogenous osteomyelitis of the hip bones in children.Material and methods. The clinical features of acute osteomyelitis of the hip joint were studied in 90 children aged between 2 and 16 years during 2017-2023. In the early stages of the disease, 9 (10.0%) patients were admitted before 3 days after the onset of the disease, and 81 (90.0%) patients were admitted later than 3 days. The proximal femoral metaepiphysis was involved in 78 (86.7%) cases, the iliac bones in 10 (11.1%), the pubic bone in 1 (1.1%) and the sacroiliac joint in 1 (1.1%).Results and discussion. Examining the clinical picture of the disease, the main symptoms were: pain in the affected area - 87 (96.7%) patients, sometimes with pain radiating to nearby areas of the body, fever - 83 (92.2%), forced position of the affected limb with refusal to walk - 79 (88.8%), and limping in 11 (12.2%) patients. In addition, purulent leakage was observed in 2 cases, in the left pubic bone lesion purulent leakage was observed in the area of the inner surface of the left thigh and in the iliac bone lesion in the iliopsoas muscle.Conclusions. Acute haematogenous osteomyelitis of the bones of the hip joint in children usually begins acutely against the background of a healthy condition of the child with a triad of symptoms: pain, increase in body temperature, forced position of the limb. Local symptoms of the disease depend on the location of the primary focus, the degree of involvement of joints and soft tissues in the process.

A Lyapunov-based adaptive control strategy with fault-tolerant objectives for proton exchange membrane fuel cell air supply systems

Proton exchange membrane fuel cells (PEMFCs) are being extensively studied for large-scale applications. The need for reliable and safe system integration processes emphasizes the importance of health-conscious control research. Considering their high-frequency operation and load variations, the reliability of PEMFCs can be compromised by mechanical failures within air supply systems. Therefore, this paper proposes an adaptive control strategy with fault-tolerant objectives for regulating the oxygen excess ratio (OER). Specifically, it addresses two common faults within air compressors, namely compressor overheating and increased mechanical friction. While these faults have been studied in fault diagnosis research, their treatment within the context of fault-tolerant control is relatively uncommon. To ensure reliable OER regulation under multiple fault occurrences, estimator-based parameter adaptation laws are firstly derived using Lyapunov theory during the stability demonstration process. Then, the baseline controller is designed using an extended state observer and feedback linearization, with a clear presentation of the existence and stability of the state transformation. Furthermore, extensive numerical tests are conducted to demonstrate the effectiveness of the proposed control strategy. The proposed adaptive control strategy ensures consistent regulation outcomes without compromising performance under healthy conditions, highlighting its potential for large-scale application as a standard control approach in practical applications.

Changes in the hematology and blood metabolites of guinea pigs (Cavia porcellus) under intensive rearing system in humid tropical conditions

Guinea pigs in intensive production generates an imperative necessity of physio-pathological bases for diagnosing their state of welfare, health, and production; those which are available for this species are referred to as laboratory or companion animal. The aim of this research is to determine changes in hematological and blood metabolites profiles in relation to age of Cavia porcellus reared in intensive system at 660 masl in humid tropic. For this purpose, forty 15-120 days old guinea pig in healthy conditions from the inti x Peru lines born in the humid tropic were used and the evaluation ages were 15-21, 22-35, 36-60 and 61-120 days. Blood samples were obtained by puncture of the cephalic vein; profiles of erythrocytes (RBC), total leucocytes (WBC), lymphocytes, granulocytes, hematocrit, hemoglobin, MCV, MCH and MCHC indices were determined. In serum, profiles of glucose, total protein (TP), albumin, total cholesterol (TC), triglycerides, total bilirubin (TB), and direct bilirubin (DB), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. Hemoglobin profile, MCH and MCHC indices increased as age increased (p &lt; 0,05) and the erythrocytes, leucocytes, hematocrit, hemoglobin profiles and MCV, MCH, MCHC indices showed the narrower interval ranges in the 15-35and 61-120-days old guinea pigs. Profiles of TP, DB and AST showed increase with age (p &lt; 0,05) and the DB, AST, ALT, and TC profiles showed the narrower interval range at 36-120 days old. The hematological and blood metabolites profiles of guinea pigs raised in intensive system in humid tropical conditions show significant changes with production age. .

Analisa Laporan Keuangan untuk Menilai Kinerja Keuangan CV. D’printing

This study aims to evaluate the financial performance of CV. D'Printing by analyzing liquidity, solvency, profitability, and activity ratios. The research is quantitative with a descriptive approach. The data analyzed comprises the financial statements of CV. D'Printing for the 2019-2023 period. The analysis techniques used are quantitative analysis and time series analysis, comparing financial ratios from one period to another. The results indicate that the company's liquidity and solvency ratios are in good and healthy condition. However, the activity ratios show suboptimal performance, with a decline in percentages each year. Overall, CV. D'Printing has a solid financial performance, although some areas need improvement..

Study of ZnO nanoparticle-doped dental adhesives on enamels with fluorosis: Electron microscopy, elemental composition and shear bond strength analysis.

This study aimed to evaluate dental adhesives containing different concentrations of zinc oxide nanoparticles (ZnO-NPs) for their use in the treatment of dental fluorosis, observe the interaction of the adhesive on healthy enamel surfaces and with mild and moderate fluorosis, measure the adhesive strength and fluorosis, and determine the phosphorus (P) and calcium (Ca) content on these surfaces, as a reference for the potential use of this adhesive with ZnO-NPs for dental fluorosis treatment. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) were used to characterise the ZnO-NPs and analyse the weight percentages of P and Ca in the enamel using X-ray energy dispersive spectroscopy (EDS) and the adhesive strength using a universal mechanical testing machine. FESEM characterisation revealed that the ZnO-NPs were less than 100nm in size, with quasi-spherical and hexagonal prism shapes. The synthesis of the ZnO-NPs was confirmed by TEM, revealing their hexagonal crystalline structure. The adhesive strength by the universal mechanical testing machine showed that the adhesive with a 3% wt. concentration of ZnO-NPs was better in the three groups of teeth, showing higher adhesive strength in teeth with mild (15.15MPa) and moderate (12.76MPa) fluorosis surfaces, and was even higher than that in healthy teeth (9.65MPa). EDS analysis showed that teeth with mild and moderate fluorosis had the highest weight percentages of P and Ca, but there were no statistically significant differences compared to healthy teeth and teeth treated with adhesives. Lay description: This study focused on testing a new dental adhesive containing small particles called ZnO nanoparticles (ZnO-NPs). This study aimed to demonstrate whether this adhesive with ZnO-NPs could be useful for treating dental fluorosis by improving its adhesion to teeth. One of the first objectives was to determine whether the dental adhesive could adhere better to teeth affected by mild or moderate fluorosis than to healthy teeth by measuring whether the levels of two important elements for healthy teeth, calcium (Ca) and phosphorus (P), were affected by the adhesive. The size and shape of the small particles and teeth with mild or moderate fluorosis were observed using scanning electron microscopy. The nanoparticles were small (< 100nm) and had specific quasi-spherical and hexagonal prismatic shapes. More damage to the enamel was observed in teeth with mild or moderate fluorosis than in healthy teeth. The adhesive strength test demonstrated that the dental adhesive with 3% ZnO-NPs had the best adhesion on all healthy conditions of teeth. It was particularly effective in teeth with mild or moderate fluorosis. Finally, the evaluation of the levels of P and Ca on the enamel showed that teeth with fluorosis had higher levels of these elements, but using the dental adhesive with ZnO-NPs did not change the levels of these elements significantly because the adhesive avoided greater detachment because of greater adhesion to these surfaces. In conclusion, adding these small particles to dental adhesives could be an option for treating teeth affected by fluorosis. It stuck well and did not affect the levels of the important elements in the teeth.

Targeting high-affinity nicotinic receptors protects against the functional consequences of β-amyloid in mouse hippocampus.

The accumulation of β-amyloid oligomers is a hallmark of Alzheimer's disease, inducing neural and network dysfunction in the early stages of pathology. The hippocampus is affected early in the pathogenesis of AD, however the impact of soluble β-amyloid on the dentate gyrus (DG) subregion of the hippocampus and its interaction with nicotinic acetylcholine receptors (nAChRs) within this region are not known. Using a localized model of over-expression, we show that β-amyloid induces early-onset neuronal hyperactivity and hippocampal-dependent memory deficits in mice. Further, we find the DG region to be under potent and sub-type specific nicotinic control in both healthy and pathophysiological conditions, with targeted receptor inhibition leading to a mnemonic rescue against localized amyloidosis. We show that while neurogenesis and synaptic functions are not severely affected in our model, reducing β2-containing nAChR function is associated with the promotion of young adult-born neurons within the pathological network, suggesting a possible protective mechanism. Our data thus reveal the DG network level changes which occur in the early-stages of β-amyloid accumulation and highlight the downstream consequences of targeted nicotinic neuromodulation.

Wind Turbine Blade Fault Diagnosis: Approximate Entropy as a Tool to Detect Erosion and Mass Imbalance

Wind energy is a clean, sustainable, and renewable source. It is receiving a large amount of attention from governments and energy companies worldwide as it plays a significant role as an alternative source of energy in reducing carbon emissions. However, due to long-term operation in reduced and difficult weather conditions, wind turbine blades are always seriously damaged. Hence, damage detection in blade structure is essential to evaluate its operational condition and ensure its structural integrity and safety. We aim to use fractal, entropy, and chaos concepts as descriptors for the diagnosis of wind turbine blade condition. They are, respectively, estimated by the correlation dimension, approximate entropy, and the Lyapunov exponent. Formal statistical tests are performed to check how they are different across wind turbine blade conditions. The experimental results follow. First, the correlation dimension is not able to distinguish between all conditions of wind turbine blades. Second, approximate entropy is suitable to distinguish between healthy and erosion conditions and between healthy and mass imbalance conditions. Third, chaos is not a discriminative feature to distinguish between wind turbine blade conditions. Fourth, wind turbine blades with either erosion or mass imbalance exhibit less irregularity in their respective signals than healthy wind turbine blades.

Peculiarities of working conditions for employees with a remote form of employment

Today, the problem of improving working conditions and improving their organization is quite urgent, in particular, the issue of working conditions for workers with non-standard forms of employment, in particular remote employment, which is gaining importance today, needs to be resolved. The purpose of the article is to study the peculiarities of working conditions for employees with remote employment, to identify problems and to propose ways to eliminate them. It is noted that with the appearance of non-typical (non-traditional) forms of employment on the domestic labor market, both practitioners and scientists are increasingly questioning the employer’s ability to fulfill the duty assigned to him to guarantee employees whose work does not fit into the traditional framework of labor relations, safe and healthy working conditions. Therefore, the employer using this type of employment should also take care of additional protection of employees, in particular, in matters of occupational health and safety, especially today, when the danger is different, external, military. At the same time, analyzing the current labor legislation, it was established that the employer is responsible only for “the safety and proper technical condition of the equipment and means of production, which are transferred to the employee to perform remote work”, and he does not have the obligation to ensure safe and harmless working conditions for the employee. Therefore, supporting other researchers of this issue, it is suggested that among the special conditions of the labor contract on remote work, there should also be a condition on ensuring labor safety, in order to oblige the employer to ensure the safety of the work of employees of the remote form of employment, in particular, to make sure that the assigned work can be performed safely at home by such an employee, has appropriate equipment and tools for safe work at home, received appropriate information, instructions and training (including in the event of an emergency), and also took measures to ensure the physical and psychological well-being of employees. Since remote work should not entail any restrictions on the scope of labor rights of employees, that is, a remote worker should have the same rights and obligations as other employees.

Fault Detection of Rotating Machines Using poly-Coherent Composite Spectrum of Measured Vibration Responses with Machine Learning

This study presents an efficient vibration-based fault detection method for rotating machines utilising the poly-coherent composite spectrum (pCCS) and machine learning techniques. pCCS combines vibration measurements from multiple bearing locations into a single spectrum, retaining amplitude and phase information while reducing background noise. The use of pCCS significantly reduces the number of extracted parameters in the frequency domain compared to using individual spectra at each measurement location. This reduction in parameters is crucial, especially for large industrial rotating machines, as processing and analysing extensive datasets demand significant computational resources, increasing the time and cost of fault detection. An artificial neural network (ANN)-based machine learning model is then employed for fault detection using these reduced extracted parameters. The methodology is developed and validated on an experimental rotating machine at three different speeds: below the first critical speed, between the first and second critical speeds, and above the second critical speed. This range of speeds represents the diverse dynamic conditions commonly encountered in industrial settings. This study examines both healthy machine conditions and various simulated fault conditions, including misalignment, rotor-to-stator rub, shaft cracks, and bearing faults. By combining the pCCS technique with machine learning, this study enhances the reliability, efficiency, and practical applicability of fault detection in rotating machines under varying dynamic conditions and different machine conditions.

Numerical assessment of using various outlet boundary conditions on the hemodynamics of an idealized left coronary artery model.

Vascular diseases are greatly influenced by the hemodynamic parameters and the accuracy of determining these parameters depends on the use of correct boundary conditions. The present work carries out a two-way fluid-structure interaction (FSI) simulation to investigate the effects of outlet pressure boundary conditions on the hemodynamics through the left coronary artery bifurcation with moderate stenosis (50%) in the left anterior descending (LAD) branch. The Carreau viscosity model is employed to characterise the shear-thinning behaviour of blood. The results of the study reveal that the employment of zero pressure at the outlet boundaries significantly overestimates the values of hemodynamic variables like wall shear stress (WSS), and time-averaged wall shear stress (TAWSS) compared with human healthy and pulsatile pressure outlet conditions. However, the difference between these variables is marginally low for human healthy and pulsatile pressure outlets. The oscillatory shear index (OSI) remains the same across all scenarios, indicating independence from the outlet boundary condition. Furthermore, the magnitude of negative axial velocity and pressure drop across the plaque are found to be higher at the zero pressure outlet boundary condition.

Hepatic stellate cells in zone 1 engage in capillarization rather than myofibroblast formation in murine liver fibrosis

The combination of lineage tracing and immunohistochemistry has helped to identify subpopulations and fate of hepatic stellate cells (HSC) in murine liver. HSC are sinusoidal pericytes that act as myofibroblast precursors after liver injury. Single cell RNA sequencing approaches have recently helped to differentiate central and portal HSC. A specific Cre line to lineage trace portal HSC has not yet been described. We used three Cre lines (Lrat-Cre, PDGFRβ-CreERT2 and SMMHC-CreERT2) known to label mesenchymal cells including HSC in combination with a tdTomato-expressing reporter. All three Cre lines labeled populations of HSC as well as smooth muscle cells (SMC). Using the SMMHC-CreERT2, we identified a subtype of HSC in the periportal area of the hepatic lobule (termed zone 1-HSC). We lineage traced tdTomato-expressing zone 1-HSC over 1 year, described fibrotic behavior in two fibrosis models and investigated their possible role during fibrosis. This HSC subtype resides in zone 1 under healthy conditions; however, zonation is disrupted in preclinical models of liver fibrosis (CCl4 and MASH). Zone 1-HSC do not transform into αSMA-expressing myofibroblasts. Rather, they participate in sinusoidal capillarization. We describe a novel subtype of HSC restricted to zone 1 under physiological conditions and its possible function after liver injury. In contrast to the accepted notion, this HSC subtype does not transform into αSMA-positive myofibroblasts; rather, zone 1-HSC adopt properties of capillary pericytes, thereby participating in sinusoidal capillarization.