State-of-the-art ensemble learning and unsupervised learning in fatigue crack recognition of glass fiber reinforced polyester composite (GFRP) using acoustic emission

Fatigue strength is one of the most important properties of composite materials because it directly relates to their lifespan. Acoustic emission (AE) is a passive structural health monitoring (SHM) technique that provides real-time damage detection based on stress waves generated by cracks in the structure. This study evaluates the damage progression on glass fiber reinforced polyester composite specimens using different approaches of machine learning. Different methodologies for damage detection and characterization of AE parameters are presented. Three different ensemble learning methods namely, XGboost, LightGBM, and CatBoost were chosen to predict damages and AE parameters. SHAP values were used to select AE key features and K-means algorithms were employed to classify damage severity. The accuracy of these approaches demonstrates the reliability of various machine learning techniques in predicting the fatigue life of composite materials using acoustic emission.

Mitochondrial transfer from cancer associated fibroblasts increases migration in aggressive breast cancer

Cancer associated fibroblasts (CAFs) have distinct roles within the tumor microenvironment, which may impact the mode and efficacy of tumor cell migration. CAFs are known to increase invasion of less-aggressive breast cancer cells through matrix remodeling and leader-follower dynamics. Here, we demonstrate that CAFs communicate with breast cancer cells through the formation of contact-dependent tunneling nanotubes (TNTs) that allow for the exchange of cargo between cell types. The transferring of CAF mitochondria is an integral cargo component, and CAF mitochondria are sufficient to increase the 3D migration of cancer cells. This cargo transfer results in an increase in mitochondrial ATP production in cancer cells while having negligible impact on glycolytic ATP production. Manually increasing mitochondrial oxidative phosphorylation (OXPHOS) by providing extra substrates for OXPHOS fails to enhance cancer cell migration unless glycolysis is maintained at a constant level. Together, these data indicate that tumor-stromal crosstalk via TNTs and the associated metabolic symbiosis is a finely controlled mechanism by which tumor cells co-opt their microenvironment to promote cancer progression and may become a potential therapeutic target.

Fabrication, characterization and biological properties evaluation of bioactive scaffold based on mineralized carbon nanofibers

Tissue engineering as an innovative approach aims to combine engineering, biomaterials and biomedicine to eliminate the drawbacks of conventional bone defect treatment. In the current study, we fabricated bioengineered electroactive and bioactive mineralized carbon nanofibers as the scaffold for bone tissue engineering applications. The scaffold was fabricated using the sol-gel method and thoroughly characterized by SEM imaging, EDX analysis and a 4-point probe. The results showed that the CNFs have a diameter of 200 ± 19 nm and electrical conductivity of 1.02 ± 0.12 S cm-1. The in vitro studies revealed that the synthesized CNFs were osteoactive and supported the mineral crystal deposition. The hemolysis study confirmed the hemocompatibility of the CNFs and cell viability/proliferation sassy using an MTT assay kit showed the proliferative activities of mineralized CNFs. In conclusion, this study revealed that the mineralized CNFs synthesized by the combination of sol-gel and electrospinning techniques were electroactive, osteoactive and biocompatible, which can be considered an effective bone tissue engineering scaffold.Communicated by Ramaswamy H. Sarma.

Synthesis, surface modifications, and biomedical applications of carbon nanofibers: Electrospun vs vapor-grown carbon nanofibers

Engineered nanostructures are materials with promising properties, enabled by precise design and fabrication, as well as size-dependent effects. Biomedical applications of nanomaterials in disease-specific prevention, diagnosis, treatment, and recovery monitoring require precise, specific, and sophisticated approaches to yield effective and long-lasting favorable outcomes for patients. In this regard, carbon nanofibers (CNFs) have been indentified due to their interesting properties, such as good mechanical strength, high electrical conductivity, and desirable morphological features. Broadly speaking, CNFs can be categorized as vapor-grown carbon nanofibers (VGCNFs) and carbonized CNFs (e.g., electrospun CNFs), which have distinct microstructure, morphologies, and physicochemical properties. In addition to their physicochemical properties, VGCNFs and electrospun CNFs have distinct performances in biomedicine and have their own pros and cons. Indeed, several review papers in the literature have summarized and discussed the different types of CNFs and their performances in the industrial, energy, and composites areas. Crucially however, there is room for a comprehensive review paper dealing with CNFs from a biomedical point of view. The present work therefore, explored various types of CNFs, their fabrication and surface modification methods, and their applications in the different branches of biomedical engineering.

Disrupted Surfaces of Porous Membranes Reduce Nuclear YAP Localization and Enhance Adipogenesis through Morphological Changes

The disrupted surface of porous membranes, commonly used in tissue-chip and cellular coculture systems, is known to weaken cell-substrate interactions. Here, we investigated whether disrupted surfaces of membranes with micron and submicron scale pores affect yes-associated protein (YAP) localization and differentiation of adipose-derived stem cells. We found that these substrates reduce YAP nuclear localization through decreased cell spreading, consistent with reduced cell-substrate interactions, and in turn enhance adipogenesis while decreasing osteogenesis.

Microengineered 3D Collagen Gels with Independently Tunable Fiber Anisotropy and Directionality

Cellular processes, including differentiation, proliferation, and migration, have been linked to the alignment (anisotropy) and orientation (directionality) of collagen fibers in the native extracellular matrix (ECM). Given the critical role that biophysical cell-matrix interactions play in regulating biological functions, several microfluidic-based methods have been used to establish 3D collagen gels with defined fiber properties; these gels have helped to establish quantitative relationships between structural ECM cues and observed cell responses. Although existing microfluidic fabrication methods provide excellent definition over collagen fiber anisotropy, they have not demonstrated the independent control over fiber anisotropy and directionality necessary to replicate in vivo collagen architecture. Therefore, to advance collagen microengineering capabilities, we present a user-friendly technology platform that uses controlled fluid flows within a non-uniform microfluidic channel network to create collagen landscapes that can be tuned as a function of extensional strain rate. Herein, we demonstrate capabilities to i) control the degree of fiber anisotropy, ii) create spatial gradients in fiber anisotropy, iii) independently define fiber directionality, and iv) generate multi-material interfaces within a 3D environment. We then address the practical issue of integrating cells into microfluidic systems by using a peel-off template technique to provide direct access to microengineered collagen gels, and demonstrate that cells respond to the defined properties of the landscape. Finally, the platform's modular capability is highlighted by integrating a sub-micrometer thick porous parylene membrane onto the microengineered collagen as a method to define cell-substrate interactions.

Robust and Gradient Thickness Porous Membranes for In Vitro Modeling of Physiological Barriers

Porous membranes are fundamental elements for tissue-chip barrier and co-culture models. However, the exaggerated thickness of commonly available membranes may represent a stumbling block impeding a more accurate in vitro modeling. Existing techniques to fabricate membranes such as solvent cast, spin-coating, sputtering and PE-CVD result in uniform thickness films. Here, we developed a robust method to generate ultrathin porous parylene C (UPP) membranes not just with precise thicknesses down to 300 nm, but with variable gradients in thicknesses, while at the same time having porosities up to 25%. We also show surface etching and increased roughness lead to improved cell attachment. Next, we examined the mechanical properties of UPP membranes with varying porosity and thickness and fit our data to previously published models, which can help determine practical upper limits of porosity and lower limits of thickness. Lastly, we validate a straightforward approach allowing the successful integration of the UPP membranes into a prototyped 3D-printed scaffold, demonstrating mechanical robustness and allowing cell adhesion under varying flow conditions. Collectively, our results support the integration and the use of UPP membranes to examine cell-cell interaction in vitro.

In vitro Studies of Transendothelial Migration for Biological and Drug Discovery

Inflammatory diseases and cancer metastases lack concrete pharmaceuticals for their effective treatment despite great strides in advancing our understanding of disease progression. One feature of these disease pathogeneses that remains to be fully explored, both biologically and pharmaceutically, is the passage of cancer and immune cells from the blood to the underlying tissue in the process of extravasation. Regardless of migratory cell type, all steps in extravasation involve molecular interactions that serve as a rich landscape of targets for pharmaceutical inhibition or promotion. Transendothelial migration (TEM), or the migration of the cell through the vascular endothelium, is a particularly promising area of interest as it constitutes the final and most involved step in the extravasation cascade. While in vivo models of cancer metastasis and inflammatory diseases have contributed to our current understanding of TEM, the knowledge surrounding this phenomenon would be significantly lacking without the use of in vitro platforms. In addition to the ease of use, low cost, and high controllability, in vitro platforms permit the use of human cell lines to represent certain features of disease pathology better, as seen in the clinic. These benefits over traditional pre-clinical models for efficacy and toxicity testing are especially important in the modern pursuit of novel drug candidates. Here, we review the cellular and molecular events involved in leukocyte and cancer cell extravasation, with a keen focus on TEM, as discovered by seminal and progressive in vitro platforms. In vitro studies of TEM, specifically, showcase the great experimental progress at the lab bench and highlight the historical success of in vitro platforms for biological discovery. This success shows the potential for applying these platforms for pharmaceutical compound screening. In addition to immune and cancer cell TEM, we discuss the promise of hepatocyte transplantation, a process in which systemically delivered hepatocytes must transmigrate across the liver sinusoidal endothelium to successfully engraft and restore liver function. Lastly, we concisely summarize the evolving field of porous membranes for the study of TEM.

Micropatterned Poly(ethylene glycol) Islands Disrupt Endothelial Cell-Substrate Interactions Differently from Microporous Membranes

Porous membranes are ubiquitous in cell co-culture and tissue-on-a-chip studies. These materials are predominantly chosen for their semi-permeable and size exclusion properties to restrict or permit transmigration and cell-cell communication. However, previous studies have shown pore size, spacing and orientation affect cell behavior including extracellular matrix production and migration. The mechanism behind this behavior is not fully understood. In this study, we fabricated micropatterned non-fouling polyethylene glycol (PEG) islands to mimic pore openings in order to decouple the effect of surface discontinuity from potential grip on the vertical contact area provided by pore wall edges. Similar to previous findings on porous membranes, we found that the PEG islands hindered fibronectin fibrillogenesis with cells on patterned substrates producing shorter fibrils. Additionally, cell migration speed over micropatterned PEG islands was greater than unpatterned controls, suggesting that disruption of cell-substrate interactions by PEG islands promoted a more dynamic and migratory behavior, similarly to enhanced cell migration on microporous membranes. Preferred cellular directionality during migration was nearly indistinguishable between substrates with identically patterned PEG islands and previously reported behavior over micropores of the same geometry, further confirming disruption of cell-substrate interactions as a common mechanism behind the cellular responses on these substrates. Interestingly, compared to respective controls, there were differences in cell spreading and a lower increase in migration speed over PEG islands compared prior results on micropores with identical feature size and spacing. This suggests that membrane pores not only disrupt cell-substrate interactions, but also provide additional physical factors that affect cellular response.

Body image mediates the impact of pain on depressive symptoms in patients with systemic lupus erythematosus

Objective

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with treatment manifestations that can cause changes in appearance, including skin rashes, alopecia, vitiligo, and scars. SLE has been shown to adversely impact body image outcomes, and previous research has identified that greater disease activity is associated with worse body image outcomes which, in turn, are associated with greater depressive symptoms. For patients with SLE who also experience significant pain, poor body image outcomes may further compromise wellbeing and lead to greater depressive symptoms. The role of pain in body image has not been explored in SLE. Thus, the present study examined whether body image (specifically, body image-related quality of life) serves as a mediator of the relationship between pain and depressive symptoms among patients with SLE.

Methods

Multiple mediation analysis was used to examine the hypothesis that body image-related quality of life mediates the relationship between pain and depressive symptoms in a sample of patients with SLE ( N = 135) from an urban region in Los Angeles, California.

Results

The sample was predominately female (92.6%) with a mean disease duration of approximately 17 years. Approximately one-quarter of the sample had elevated depressive symptoms. Body image-related quality of life was a significant mediator in the relationship between pain and depressive symptoms. The model accounted for 51% of the total variance in depressive symptoms ( R2 = 0.51).

Conclusion

This cross-sectional study suggested that body image-related quality of life may mediate the effects of pain on depressive symptoms among patients with SLE.

Psychometric validation of the Arthritis Helplessness Index in systemic lupus erythematosus

Objective Helplessness is a relevant construct in systemic lupus erythematosus (SLE), an unpredictable chronic illness with no known cure characterized by relapsing and remitting features. However, no measure of helplessness has been validated in this population. The present study examined the structural validity, reliability, and convergent validity of the Arthritis Helplessness Index, a measure initially developed for rheumatoid arthritis populations, in a sample of patients with SLE. Methods Patients with SLE ( N = 136) receiving medical care at a private hospital completed the Arthritis Helplessness Index and other self-report measures. The structural validity of the Arthritis Helplessness Index was examined using confirmatory factor analysis. Internal consistency reliability was evaluated with Cronbach's coefficient alpha. Pearson product-moment correlations were used to examine convergent validity with measures of depression, anxiety and mastery. Results The five-item Arthritis Helplessness Index-Helplessness measure demonstrated a tenable factor structure (comparative fit index 0.98, root mean square error of approximation 0.06, standardized root mean residual 0.04). Internal consistency reliability was fair (α = 0.69). Convergent validity was evidenced by significant correlations with measures of depression, anxiety and mastery. Conclusion The five-item Arthritis Helplessness Index-Helplessness scale can confidently be used as a measure of helplessness in SLE.

Abstract P2-03-07: Digital image analysis of Ki67 in hot spots is superior to alternative proliferation associated markers in breast cancer

INTRODUCTION

Proliferative activity is one of the most important prognostic parameters in cancer. During the pathological examination of breast tumors, it is routinely evaluated by a count of the number of mitoses. Adding immunohistochemical stains of the nuclear protein Ki67 provides extra prognostic and predictive information. However, the currently used methods for both of these evaluations battle imperfections, primarily in reproducibility. In this study, we make an equally broad and detailed evaluation of mitoses, Ki67 and the more recently described Phosphohistone H3 (PHH3) in primary breast cancer using digital image analysis (DIA). Furthermore, we aim to investigate the prognostic and predictive value of proliferation-associated biomarkers in breast cancer stromal cells in relation to patient outcome.

MATERIALS AND METHODS

Two cohorts of primary breast cancer specimens (total n=297) with clinicopathological data including >10 years survival data, were sectioned and stained for Ki67, PHH3 and pancytokeratin (CKMNF116) and all glass slides were digitally scanned at x20. The DIA software used was the Visiopharm Integrator System (VIS) by Visiopharm A/S, Hoersholm, Denmark. VIS operates by a 'digital fusion' method that automatically excludes non-epithelial tissue restricting the analysis of the biomarkers (Ki67 and PHH3) to CKMNF116 positive cells. Both manual and DIA scores were compared for sensitivity and specificity for the gene expression based Luminal B versus A subtype, for high versus low transcriptomic grade as well as for their prognostic value in terms of Cox regression hazard ratios and breast cancer specific and overall survival. Further, we investigated whether the expression of Ki67 in the tumors' hot spots, invasive edges or as an average across all regions should be assessed for maximum power in relation to these outcomes. In addition, by inverting the DIA algorithm run by the VIS on the same cohorts, the expression of Ki67 and PHH3 was evaluated in the tumor stromal compartment.

RESULTS

Regardless of tumor region, DIA of Ki67 outperformed the other markers in sensitivity and specificity for gene expression subtypes and transcriptomic grade. In contrast to mitotic counts, tumors with high expression of Ki67 as defined by DIA, had significantly increased hazard ratio for all-cause mortality within 10 years from diagnosis. DIA of Ki67 was superior to manual Ki67 and PHH3 evaluations as well as to mitotic counts in terms of separation of patients with poor versus relatively good survival. Finally, we replaced the manual mitotic counts with DIA of Ki67 in hot spots as the marker for proliferation when determining histological grade. This increased the differences in estimated mean overall survival between the highest and lowest grades and added significantly more prognostic information to the classic Nottingham histological grade.

CONCLUSIONS

We conclude that digital image analysis of Ki67 in hot spots should be suggested as the marker of choice for proliferative activity in breast cancer.

Citation Format: Robertson S, Stålhammar G, Wedlund L, Gholizadeh S, Lippert M, Rantaleinen M, Bergh J, Hartman J. Digital image analysis of Ki67 in hot spots is superior to alternative proliferation associated markers in breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-03-07.

The mediational role of helplessness in psychological outcomes in systemic lupus erythematosus

Objective Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can result in disability and psychological distress. Although pain has been associated with depressive symptomatology and stress in SLE, a paucity of theoretical models have been used to explain the relationship between pain and psychological distress in this population. Thus, the present study examined helplessness as a mediator of the relationship between pain and psychological distress among patients with SLE. Methods Multiple mediation analysis was used to examine the hypothesis that learned helplessness mediates the relationship between pain and symptoms of anxiety, depression, and stress in a sample of patients with SLE ( N = 136) receiving medical care at Cedars Sinai Medical Center. Results The mean score on the Helplessness subscale was 14.5 ( SD = 5.4). Helplessness fully mediated the relationship between pain vitality and symptoms of anxiety (BCa 95% CI (-0.073, -0.015)), depression (BCa 95% CI (-0.502, -0.212)), and stress (BCa 95% CI (-0.063, -0.027)). Conclusion Participants reported a high level of perceived inability to control one's disease. Helplessness fully mediated the relationship between pain and measures of anxiety, depression, and perceived stress among patients with SLE.

Preparation and characterization of novel functionalized multiwalled carbon nanotubes/chitosan/β-Glycerophosphate scaffolds for bone tissue engineering

A major limitation in current tissue engineering scaffolds is that some of the most important characteristics of the intended tissue are ignored. As piezoelectricity and high mechanical strength are two of the most important characteristics of the bone tissue, carbon nanotubes are getting a lot of attention as a bone tissue scaffold component in recent years. In the present study, composite scaffolds comprised of functionalized Multiwalled Carbon Nanotubes (f-MWCNT), medium molecular weight chitosan and β-Glycerophosphate were fabricated and characterized. Biodegradability and mechanical tests indicate that while increasing f-MWCNT content can improve electrical conductivity and mechanical properties, there are some limitations for these increases, such as a decrease in mechanical properties and biodegradability in 1w/v% content of f-MWCNTs. Also, MTT cytotoxicity assay was conducted for the scaffolds and no significant cytotoxicity was observed. Increasing f-MWCNT content led to higher alkaline Phosphatase activity. The overall results show that composites with f-MWCNT content between 0.1w/v% and 0.5w/v% are the most suitable for bone tissue engineering application. Additionally, Preliminary cell electrical tests proved the efficiency of the prepared scaffolds for cell electrical applications.

Optimization of electrical stimulation parameters for MG-63 cell proliferation on chitosan/functionalized multiwalled carbon nanotube films

Combination of electrical stimulation with CNT-based conductive films and obtaining optimum signal parameters for MG-63 cells.

The Anopheles stephensi odorant binding protein 1 (AsteObp1) gene: a new molecular marker for biological forms diagnosis

Anopheles (Cellia) stephensi Liston 1901 is known as an Asian malaria vector. Three biological forms, namely "mysorensis", "intermediate", and "type" have been earlier reported in this species. Nevertheless, the present morphological and molecular information is insufficient to diagnose these forms. During this investigation, An. stephensi biological forms were morphologically identified and sequenced for odorant-binding protein 1 (Obp1) gene. Also, intron I sequences were used to construct phylogenetic trees. Despite nucleotide sequence variation in exon of AsteObp1, nearly 100% identity was observed at the amino acid level among the three biological forms. In order to overcome difficulties in using egg morphology characters, intron I sequences of An. stephensi Obp1 opens new molecular way to the identification of the main Asian malaria vector biological forms. However, multidisciplinary studies are needed to establish the taxonomic status of An. stephensi.

Molecular detection of knockdown resistance (kdr) in Blattella germanica (Blattodea: Blattellidae) from northwestern Iran

Pyrethroid insecticides are highly insecticidal compounds that are widely used against the German cockroach, a significant household insect pest. In several insect species, there is a point mutation in the para-type sodium channel gene associated with knockdown resistance (kdr). In the current study, genomic DNA was analyzed in the region where the kdr and super-kdr (an enhanced form of pyrethroid resistance) mutations reside in Blatella germanica (L., 1767) (Blattodea: Blattellidae) collected from Iran. Studies on the extracted DNA from hand-captured German cockroach specimens were conducted by polymerase chain reaction and sequencing to detect related mutations. The kdr mutation, substitution of G for C (L1014F), which results in amino acid replacement (leucine with phenylalanine), was detected in all 18 sequenced specimens from three different locations. However, the super-kdr mutation (M918T), which is detected in super-kdr house flies, was not found in the sequences of the current study. The high ratio of the kdr mutation in a field population of B. germanica in Urmia confirms that the individuals are homozygous. These data should be helpful in designing and implementing a control program and resistance management.

First record of a new member of Anopheles Hyrcanus Group from Iran: molecular identification, diagnosis, phylogeny, status of kdr resistance and Plasmodium infection

The current study aimed to provide further evidence on the status of species composition, insecticide resistance, and vectorial capacity within the members of Anopheles (Anopheles) Hyrcanus Group in Ardebil, Giulan, and Khuzestan provinces of Iran. Sequencing the internal transcribed spacer 2 (ITS2) of ribosomal DNA gene led to identification of two members of Hyrcanus complex: Anopheles hyrcanus Pallas and a new species/form, hereafter called Anopheles hyrcanus sp(IR) as a world record. Furthermore, we identified and compared partial sequences of exons I and II and the whole intron I region of insecticide resistance-related voltage-gated sodium channel (vgsc) gene in populations of Hyrcanus Group and other main old world Anopheles species. The ITS2 and vgsc sequences in members of Hyrcanus Group and other Anopheles species were used for construction of phylogenetic tree, which demonstrated the evolutionary relatedness among Western and Eastern Palearctic taxa within the Hyrcanus Group. A nested polymerase chain reaction assay for detection of Plasmodium species revealed the infection of Plasmodium falciparum within An. hyrcanus collected from Fooman district in Guilan province. The data from this study led to the introduction of a new member/form within the Hyrcanus Group, identification and definition of the status of knockdown resistance related to pyrethroids and DDT in their vgsc gene, detection of Plasmodium infection, and further evidence on genetic relatedness within these taxa. The overall results may suggest reconsidering the role ofAn. hyrcanus in malaria transmission, which would be useful for implementation and evaluation of malaria control programs in Western Palearctic region.