<i>miR-103-3p</i> regulates the differentiation of bone marrow mesenchymal stem cells in myelodysplastic syndrome

The pathogenesis of myelodysplastic syndrome (MDS) may be related to the abnormal expression of microRNAs (miRNAs), which could influence the differentiation capacity of mesenchymal stem cells (MSCs) towards adipogenic and osteogenic lineages. In this study, exosomes from bone marrow plasma were successfully extracted and identified. Assessment of miR-103-3p expression in exosomes isolated from BM in 34 MDS patients and 10 controls revealed its 0.52-fold downregulation in patients with MDS compared with controls (NOR) and was downregulated 0.55-fold in MDS-MSCs compared with NOR-MSCs. Transfection of MDS-MSCs with the miR-103-3p mimic improved osteogenic differentiation and decreased adipogenic differentiation in vitro, while inhibition of miR-103-3p showed the opposite results in NOR-MSCs. Thus, the expression of miR-103-3p decreases in MDS BM plasma and MDS-MSCs, significantly impacting MDS-MSCs differentiation. The miR-103-3p mimics may boost MDS-MSCs osteogenic differentiation while weakening lipid differentiation, thereby providing possible target for the treatment of MDS pathogenesis.     

Ultrastructural characteristics of ovine bone marrow‐derived mesenchymal stromal cells cultured with a silicon stabilized tricalcium phosphate bioceramic

Bioceramics are being used in experimental bone engineering application in association with bone marrow derived mesenchymal stem cells (BM‐MSCs) as a new therapeutic tool, but their effects on the ultrastructure of BM‐MSCs are yet unknown. In this study we report the morphological features of ovine (o)BM‐MSCs cultured with Skelite, a resorbable bioceramic based on silicon stabilized tricalcium phosphate (SiTCP), able to promote the repair of induced bone defect in sheep model. oBM‐MSCs were isolated from the iliac crest, cultured until they reached near‐confluence and incubated with SiTCP. After 48 hr the monolayers were highly damaged and only few cells adhered to the plastic. Thus, SiTCP was removed, and after washing the cells were cultured until they became confluent. Then, they were trypsinizated and processed for transmission electron microscopy (TEM) and RT‐PCR analysis. RT‐PCR displayed that oBM‐MSCs express typical surface marker for MSCs. TEM revealed the presence of electron‐lucent cells and electron‐dense cells, both expressing the CD90 surface antigen. The prominent feature of electron‐lucent cells was the concentration of cytoplasmic organelles around the nucleus as well as large surface blebs containing glycogen or profiles of endoplasmic reticulum. The dark cells had a multilocular appearance by the presence of peripheral vacuoles. Some dark cells contained endocytic vesicles, lysosomes, and glycogen aggregates. oBM‐MSCs showed different types of specialized interconnections. The comparison with ultrastructural features of untreated oBM‐MSCs suggests the light and dark cells are two distinct cell types which were differently affected by SiTCP bioceramic. Skelite cultured ovine BM‐MSCs display electron‐dense and electron‐lucent cells which are differently affected by this bioceramic. This suggests that they could play a different role in bioceramic based therapy.     

Nanoscale distribution of CD20 on B‐cell lymphoma tumour cells and its potential role in the clinical efficacy of rituximab

Rituximab is an exciting monoclonal antibody drug approved for treating B‐cell lymphomas and its target is the CD20 antigen which is expressed on the surface of B cells. In recent years, the variable efficacies of rituximab among different lymphoma patients have become an important clinical issue and urgently need to be solved for further development of antibodies with enhanced efficacies. In this work, atomic force microscopy (AFM) was used to investigate the nanoscale distribution of CD20 on the surface of tumour B cells from lymphoma patients to examine its potential role in the clinical therapeutic effects of rituximab. By performing ROR1 fluorescence labelling (ROR1 is a specific tumour cell surface marker) on the bone marrow cells prepared from B‐cell lymphoma patients, the tumour B cells were recognized, and then AFM tips carrying rituximabs via polyethylene glycol crosslinkers were moved to the tumour cells to probe the specific CD20‐rituximab interactions. By applying AFM single‐molecule force spectroscopy (SMFS) at the local areas (500×500 nm²) on the surface of tumour B cells, the nanoscale distributions of CD20 on the surface of tumour B cells were mapped, visually showing that CD20 distributed heterogeneously on the cell surface. Bone marrow cell samples from three clinical B‐cell lymphoma cases were collected to analyze the binding affinity and nanoscale distribution of CD20 on tumour cells. The experimental results showed that CD20 distribution on tumour cells were to some extent related to the clinical therapeutic outcomes while the CD20‐rituximab binding forces did not have distinct effects to the clinical outcomes. These results can provide novel insights in understanding the rituximab's clinical efficacies from the nanoscale distribution of CD20 on the tumour cells at single‐cell and single‐molecule levels.     

Immunophenotypic,immunocytochemistry, ultrastructural,and cytogenetic characterization of mesenchymal stem cells from equine bone marrow

The aim of this study was to isolate, culture, and characterize mesenchymal stem cells (MSCs) from horse bone marrow (BM) using the techniques of flow cytometry, immunocytochemistry, cytogenetics, and electron microscopy. Immunophenotypic analysis revealed the presence of MSCs with high expression of the CD90 marker, lower expression of the CD44 marker, and absent expression of the CD34 marker. In assays of differentiation, the positive response to osteogenic (OST), chondrogenic (CDG), and adipogenic (ADP) differentiation signals was observed and characterized by deposition of calcium‐rich extracellular matrix (OST), proteoglycans and collagen II (CDG) and intracellular deposition of fat drops (ADP). In immunocytochemical characterization, MSCs were immunopositive for CD44, vimentin, and PCNA, and they were negative for CD13. In the ultrastructural analysis of MSCs, the most outstanding characteristic was the presence of rough endoplasmic reticulum with very dilated cisterns filled with a low electrodensity material. Additionally, MSCs had normal karyotypes (2n = 64) as evidenced by cytogenetic analysis, and aneuploidy in metaphase was not observed. The protocols for isolating, culturing, and characterizing equine MSCs used in this study were shown to be appropriate for the production of a cell population with a good potential for differentiation and without aneuploidy that can be used to study future cellular therapies. Microsc. Res. Tech. 76:618–624, 2013. © 2013 Wiley Periodicals, Inc.     

Histochemical evidence of osteoclastic degradation of extracellular matrix in osteolytic metastasis originating from human lung small carcinoma (SBC-5) cells

The aim of this study was to assess the dynamics of osteoclast migration and the degradation of unmineralized extracellular matrix in an osteolytic metastasis by examining a well-standardized lung cancer metastasis model of nude mice. SBC-5 human lung small carcinoma cells were injected into the left cardiac ventricle of 6-week-old BALB/c nu/nu mice under anesthesia. At 25-30 days after injection, the animals were sacrificed and their femora and/or tibiae were removed for histochemical analyses. Metastatic lesions were shown to occupy a considerable area extending from the metaphyses to the bone marrow region. Tartrate resistant acid phosphatase (TRAPase)-positive osteoclasts were found in association with an alkaline phosphatase (ALPase)-positive osteoblastic layer lining the bone surface, but could also be localized in the ALPase-negative stromal tissues that border the tumor nodules. These stromal tissues were markedly positive for osteopontin, and contained a significant number of TRAPase-positive osteoclasts expressing immunoreactivity for CD44. We thus speculated that, mediating its affinity for CD44, osteopontin may serve to facilitate osteoclastic migration after their formation associated with ALPase-positive osteoblasts. We next examined the localization of cathepsin K and matrix metallo-proteinase-9 (MMP-9) in osteoclasts. Osteoclasts adjacent to the bone surfaces were positive for both proteins, whereas those in the stromal tissues in the tumor nests showed only MMP-9 immunoreactivity. Immunoelectron microscopy disclosed the presence of MMP-9 in the Golgi apparatus and in vesicular structures at the baso-lateral cytoplasmic region of the osteoclasts found in the stromal tissue. MMP-9-positive vesicular structures also contained fragmented extracellular materials. Thus, osteoclasts appear to either select an optimized function, namely secreting proteolytic enzymes from ruffled borders during bone resorption, or recognize the surrounding extracellular matrix by mediating osteopontin/CD44 interaction, and internalize the extracellular matrices. Microsc.     

Morphology and expression status investigations of specific surface markers on B‐cell chronic lymphocytic leukemia cells

The morphology of cells and expression status of specific surface markers [cluster of differentiation (CD)], such as CD5, CD19, CD20, CD38, and CD45, have long been considered as the essential indicators for the diagnosis and prognosis of B‐cell chronic lymphocytic leukemia (B‐CLL). Clinically, it is difficult to simultaneously obtain cell morphology and distribution of surface markers with flow cytometry, especially for some surrogate markers such as CD38. Here, as an alternative and complementary prognostic method, fluorescence microscopy and image processing method are introduced to directly visualize the cells from patients and to quantitatively determine the expression status of surface markers. In this study, the morphological parameters of B‐CLL cells were measured to establish the correlation between the cellular morphology and the surface marker expression. It was clear that the CD38+ and CD38? B‐CLL cells from the same CD38+ patients had hardly any size differences; however, an increase in perimeter was observed for CD38? patients. Moreover, the expression level of the receptors on the cell was independent of the cell size. There was no evidence showing that the expression intensities of CD19 and CD38 were related to each other for the CD38+ B‐CLL cells. On the same cells, CD5 was more selectively expressed on the cell membrane; however, the expression patterns suggested that the cell membrane of CD38? B‐CLL cells contained the least expression level of CD19. Microsc. Res. Tech. 76:1147–1153, 2013. © 2013 Wiley Periodicals, Inc.     

Bones Morphogenic Protein‐4 and retinoic acid combined treatment comparative analysis for in vitro differentiation potential of murine mesenchymal stem cells derived from bone marrow and adipose tissue into germ cells

Nowadays, infertility is no longer considered as an unsolvable disorder due to progresses in germ cells derived from stem lineage with diverse origins. Technical and ethical challenges push researchers to investigate various tissue sources to approach more efficient gametes. The purpose of the current study is to investigate the efficacy of a combined medium, retinoic acid (RA) together with Bone Morphogenic Protein‐4 (BMP4), on differentiation of Bone Marrow Mesenchymal Stem Cells (BMMSCs) and adipose‐derived mesenchymal stem cells (ADMSCs) into germ cells. Murine MSCs were obtained from both Bone Marrow (BM) and Adipose Tissue (AT) samples and were analyzed for surface markers to get further verification of their nature. BMMSCs and ADMSCs were induced into osteogenic and adipogenic lineage cells respectively, to examine their multipotency. They were finally differentiated into germ cells using media enriched with BMP4 for 4 days followed by addition of RA for 7 days (11 days in total). Analyzing of differentiation potential of BMMSCs‐ and ADMSCs were performed via Immunofluorescence, Flowcytometry and Real time‐PCR techniques for germ cell‐specific markers (Mvh, Dazl, Stra8 and Scp3). Mesenchymal surface markers (CD90 and CD44) were expressed on both BMMSCs and ADMSCs, while endothelial and hematopoietic cell markers (CD31 and CD45) had no expression. Finally, all germ‐specific markers were expressed in both BM and AT. Although germ cells differentiated from ADMSCs showed faster growth and proliferation as well as easy collection, they significantly expressed germ‐specific markers lower than BMMSCs. This suggests stronger differentiation potential of murine BMMSCs than ADMSCs.     

β-环糊精催化磷酰化氨基酸水解反应的电喷雾电离质谱研究

利用电喷雾离子阱质谱对 β-环糊精和 N-二异丙氧磷酰化氨基酸的相互作用进行了探讨。结果发现 :β-环糊精能够催化 N-二异丙氧磷酰化氨基酸的水解反应 ,并对 β-环糊精对 N-二异丙氧磷酰化氨基酸的水解反应机制进行了推测。而且还对β-环糊精和 N -二异丙氧磷酰化氨基酸以及氨基酸形成的复合物进行了碰撞诱导裂解 ( CID)研究 ,发现二者具有不同的裂解规律     

Low‐temperature glycol methacrylate resin embedding method: A protocol suitable for bone marrow immunohistochemistry,PCR, and fish analysis

Molecular analyses such as fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) are demanded to improve diagnostic accuracy in addition to immunohistopathology of bone marrow (BM) trephine specimens. Conventional BM embedding method needs decalcification, and its procedure may impair tissue morphology and DNA quality. Here, we report an undecalcified method by which glycol methacrylate resin is polymerized at low temperature (4°C). Using this method, BM enzyme activity and antigenic determinants are well preserved, and moreover, DNA extracted from plastic embedding sections is suitable for PCR amplification and sequencing, FISH analysis can be well done because of the DNA integrity of BM sections. If working with BM trephine specimen, our protocol offers the possibility to combine superior morphology with modern molecular analysis. Microsc. Res. Tech. 73:1067–1071, 2010. © 2010 Wiley‐Liss, Inc.     

Angioarchitecture of the terminal vascular system in inflammatory bowel disease—A comparative corrosion-anatomic study

The vascular origin of Crohn's disease (CD) and ulcerative colitis has been discussed but is poorly understood and investigated. A comparison of both diseases on the basis of the angioarchitecture had yet to be performed to investigate vascular morphology further and to evaluate its relevance for the etiology and differential diagnosis. The vascular system of 29 human colonic specimens of patients with CD (n=10), ulcerative colitis (n=11), and colon cancer (n=8), which were taken as controls, was perfused blood-free immediately after resection. Corrosion casts were obtained by injection of Mercox Cl and consecutive digestion with potassium hydroxide. Casts were then cut into sections, sputter coated with gold, and examined in a blinded fashion by scanning electron microscopy. Normal intestine showed a typical honeycomb appearance, the mucosal capillary network was smooth and regular, and the subepithelial vascular plexus was supplied by regularly arranged arterioles. In CD, a partially intact capillary net with alterations, dominant collecting veins, and a characteristic pattern of diameter changes with narrow segments in the capillary bed was seen. In ulcerative colitis a disruption of the colonic vascular architecture was found. The capillarization was rarefied and irregular lumps of subepithelial capillary structures were observed. The morphology of the terminal vascular bed in inflammatory bowel disease in contrast to normal controls is uniquely described. The technique of injecting fresh, human specimens was applied for the first time. The homogeneity of vascular changes within each entity seems to allow a differentiation between CD and ulcerative colitis.     

紫外光接枝丙烯酸改性废胶粉工艺优化及其复合材料的力学性能

以丙烯酸为接枝单体,二苯甲酮为光敏剂,在紫外光的引发下对废胶粉进行表面接枝,用正交方法对改性工艺进行了优化,制备了改性废胶粉/天然橡胶复合材料,表征了改性前后废胶粉的表面形貌和结构,考察了其加入量对复合材料力学性能的影响。结果表明:当丙烯酸和二苯甲酮与废胶粉的质量比分别为10%和9%,废胶粉粒径为150μm和光照时间为4min时,为最佳工艺条件,此时接枝率最高,达3.38%;接枝改性后的废胶粉表面粗糙度增加;随改性废胶粉含量的增加,复合材料的拉伸强度和邵氏A硬度先增大后降低,并在质量分数10%时达到最大值,分别为27.28MPa和69.2HSA。     

Nanoscale organization of CD4 molecules of human T helper cell mapped by NSOM and quantum dots

CD4 molecule, the surface marker of T helper cell, has been confirmed to be the main cellular receptor for the human immunodeficiency viruses HIV-1, HIV-2 and SIV. Recent research demonstrated the importance of the spatial arrangement of CD4 on the cell membrane to its binding efficiency to virus. In this article, the combined near-field scanning optical microscopy (NSOM) and quantum dots (QDs) fluorescent labeling technology were performed to investigate the nanoscale organization of CD4 molecules with a spatial resolution about 100 nm. Simultaneous topographic image of the T helper cell and fluorescent image of QDs have been directly gained by NSOM/QDs-based system. Intensity- and size-distribution histograms of the QDs fluorescent spots verify that approximately 80% of the CD4 molecules are organized in nanosized domains randomly distributed on the cell surface. Intensity-size correlation analysis revealed heterogeneity in the molecular packing density of the domains. Our results also illustrated the combination of NSOM imaging and QDs labeling is an ultrasensitive, high-resolution technique to probe nanoscale organization of molecules on the cell surface.     

Comprehensive analysis reveals an arachidonic acid metabolism-related gene signature in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is highly heterogeneous, making its prognosis prediction difficult. The arachidonic acid (AA) cascade is involved in carcinogenesis. Therefore, the metabolic enzymes of the AA cascade consist of lipoxygenases (LOXs), phospholipase A2s (PLA2s), and cyclooxygenases (COXs) along with their metabolic products, including leukotrienes. Nevertheless, the prognostic potential of AA metabolism-associated PDAC has not been explored. Herein, the mRNA expression patterns and the matching clinical information of individuals with PDAC were abstracted from online data resources. We employed the LASSO Cox regression model to develop a multigene clinical signature in the TCGA queue. The GEO queue and the ICGC queue were employed as the validation queue. There was differential expression of a significant number of AA metabolism-associated genes (56.8%) between PDAC and neighboring nonmalignant tissues in the TCGA queue. Univariate Cox regression demonstrated that 13 of the differentially expressed genes (DEGs) were linked to overall survival (OS) (p < 0.05). A 6-gene clinical signature was developed for stratifying the PDAC patients into two risk groups, with the high-risk group patients exhibiting remarkably lower OS than the low-risk group patients (p < 0.001 in the TCGA data set and the ICGC queue, and p = 0.001 in the GEO data set). The multivariate Cox data revealed the risk score as an independent OS predictor (HR > 1, p < 0.01). The receiver operating characteristic (ROC) curve verified the predictive potential of our signature. The expression and alteration of the six genes in PDAC were also validated using online databases. Functional analyses demonstrated that immune-linked cascades were enriched, and the immune status was remarkably different between the high- and low-risk groups. In summary, an AA metabolism-associated clinical gene signature can be applied for prognostic estimation in PDAC.     

Imaging and Measuring the Molecular Force of Lymphoma Pathological Cells Using Atomic Force Microscopy

Atomic force microscopy (AFM) provides a new technology to visualize the cellular topography and quantify the molecular interactions at nanometer spatial resolution. In this work, AFM was used to image the cellular topography and measure the molecular force of pathological cells from B‐cell lymphoma patients. After the fluorescence staining, cancer cells were recognized by their special morphological features and then the detailed topography was visualized by AFM imaging. The AFM images showed that cancer cells were much rougher than healthy cells. CD20 is a surface marker of B cells and rituximab is a monoclonal antibody against CD20. To measure the CD20‐rituximab interaction forces, the polyethylene glycol (PEG) linker was used to link rituximab onto the AFM tip and the verification experiments of the functionalized probe indicated that rituximab molecules were successfully linked onto the AFM tip. The CD20‐rituximab interaction forces were measured on about 20 pathological cells and the force measurement results indicated the CD20‐rituximab binding forces were mainly in the range of 110–120 pN and 130–140 pN. These results can improve our understanding of the topography and molecular force of lymphoma pathological cells. SCANNING 35:40‐46, 2013. © 2012 Wiley Periodicals, Inc.     

血清MIP-1α、sFas水平诊断自身免疫性甲状腺病价值

目的探究血清巨噬细胞炎性蛋白-1α(MIP-1α)、可溶性Fas(sFas)水平诊断自身免疫性甲状腺病价值及与细胞免疫功能关系。方法选取2017年5月~2019年5月我院收治的83例自身免疫性甲状腺病患者作为观察组,含41例桥本甲状腺炎(HT),42例Graves病(GD),同期选取61例健康体检者作为对照组。对比两组血清MIP-1α、sFas水平、甲状腺自身相关抗体[甲状腺球蛋白抗体(TGAb)、甲状腺过氧化物酶抗体(TPOAb)]、细胞免疫功能(CD4+/CD8+、CD4+),Spearman分析血清MIP-1α、sFas水平与甲状腺自身相关抗体、细胞免疫功能相关性,受试者工作特征曲线(ROC)分析血清MIP-1α、sFas水平诊断自身免疫性甲状腺病价值,Logistic回归分析自身免疫性甲状腺病发生的影响因素。结果观察组GD患者血清MIP-1α、sFas、TPOAb水平高于HT患者、对照组,TGAb低于HT患者、对照组(P<0.05);自身免疫性甲状腺病患者血清MIP-1α、sFas水平与TGAb呈负相关,与TPOAb呈正相关(P<0.05);观察组GD患者CD4+、CD4+/CD8+水平高于HT患者、对照组(P<0.05);自身免疫性甲状腺病血清MIP-1α、sFas水平与CD4+、CD4+/CD8+呈正相关(P<0.05);ROC曲线显示,血清MIP-1α诊断自身免疫性甲状腺病的AUC最大,为0.815,截断值≤157.85pg/ml,敏感度及特异度分别为78.05%、80.95%;血清MIP-1α、sFas、病程、疾病类型是引起自身免疫性甲状腺病发生危险因素(P<0.05)。结论血清MIP-1α、sFas水平变化与甲状腺自身相关抗体、细胞免疫功能有关,可作为诊断自身免疫性甲状腺病重要指标,为临床确定治疗措施提供依据。     

Influence of glass particle size of resin cements on bonding to glass ceramic: SEM and bond strength evaluation

This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass‐ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne‐particle abrasion (AA). Cements were obtained from a Bis‐GMA/TEGDMA mixture filled with 60 mass% micron‐sized (1 ± 0.2 µm) or submicron‐sized (180 ± 30 µm) Ba‐Si‐Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student‐Newman‐Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA‐submicron group had lower bond strengths than the other groups. All AA‐submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb‐like aspect in the HFA‐treated ceramic, whereas the AA‐treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA‐treated compared to AA‐treated specimens. Cracks toward the bulk of the ceramic were observed in AA‐treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect. Microsc. Res. Tech. 77:363–367, 2014. © 2014 Wiley Periodicals, Inc.     

新型冲击驱动器及其在扫描隧道显微镜中的应用

提出了一种基于压电陶瓷的新型冲击式微位移驱动器，该驱动器利用摩擦力和惯性原理使目标产生步进式的微位移。其特点是最小位移可达几纳米，并在几纳米至几微米之间连续可调，运动范围几乎不受限制，具有实用的运动速度，系统结构简单，操作与控制方便，因而可能在微纳米技术中得到广泛应用。阐述了该驱动器的工作原理和机构设计，给出了它在扫描隧道显微镜中用于探针一样品间的自动定位控制的应用实例，得到了理想的结果。     

Parametric study of the dry sliding wear behaviour of AA6082-T6/SiC and AA6082-T6/B<Subscript>4</Subscript>C composites using RSM

In this paper a parametric study of the wear behaviour of Aluminum matrix composites has been carried out. AA6082-T6/SiC and AA6082-T6/B₄C composites were fabricated using stir casting technique. The percentage of reinforcement was taken as 5, 10, 15 and 20 wt.% for both SiC and B₄C particulates. Dry sliding wear tests were conducted using pin-on-disc apparatus at room temperature and process optimization was done using Response surface methodology (RSM). Weight percentage (wt.%) of reinforcement, sliding speed, load and sliding distance were the four process parameters considered to analyse these composites wear behaviour. Analysis of variance (ANOVA) showed that sliding distance exerted the highest contribution (60.24 %) to AA6082-T6/SiC wear, followed by sliding speed (14.28 %), load (11.88 %) and reinforcement content (4.31 %). The same trend was found in AA6082-T6/B₄C composites with slightly different contribution values, namely sliding distance (63.28 %), sliding speed (14.02 %), load (10.10 %) and reinforcement content (4.05 %). RSM analysis revealed that increases in the reinforcement content and sliding speed reduce the wear rate in both composites. On the other hand, increases in load and sliding distance led to higher AA6082-T6/SiC and AA6082-T6/B₄C composites wear. The two predictive models were validated by conducting confirmation tests and certified that the developed wear predictive models are accurate and can be used as predictive tools for wear apllications.