Structural Cues Research Articles

A dual-cue network for multispectral photometric stereo

Estimating pixel-wise surface normal from a single image is a challenging task but offers great values to computer vision and robotics applications. By using the spectrally and spatially variant illumination, multispectral photometric stereo can produce pixel-wise surface normal from just one image. But multispectral photometric stereo methods may encounter the tangle problem of illumination, surface reflectance and camera response, which lead to an under-determined system. Existing approaches rely on either extra depth information or material calibration strategies, assuming a Lambertian surface condition which limits their application in practical systems. Previous learning-based methods employ fully-connected or CNN architectures to estimate surface normal. Compared with fully-connected framework, CNN takes advantage of the information embedded in the neighborhood of a surface point, but losing high-frequency surface normal details. In this paper, we present a new method that addresses this task by designing two stacked deep network. We first apply a CNN-based structural cue network to approximate coarse surface normal on small patches. Then, we use a pixel level fully-connected photometric cue network to further refine surface normal details and correct errors from the first step. The fused network is robust to non-Lambertian surfaces and complex illumination environments, such as ambient light and variant light directions. Experimental results show that our dual-cue fused network outperforms existing methods.

Impaired frequency selectivity and sensitivity to temporal fine structure, but not envelope cues, in children with mild-to-moderate sensorineural hearing loss.

Psychophysical thresholds were measured for 8-16 year-old children with mild-to-moderate sensorineural hearing loss (MMHL; N = 46) on a battery of auditory processing tasks that included measures designed to be dependent upon frequency selectivity and sensitivity to temporal fine structure (TFS) or envelope cues. Children with MMHL who wore hearing aids were tested in both unaided and aided conditions, and all were compared to a group of normally hearing (NH) age-matched controls. Children with MMHL performed more poorly than NH controls on tasks considered to be dependent upon frequency selectivity, sensitivity to TFS, and speech discrimination (/bɑ/-/dɑ/), but not on tasks measuring sensitivity to envelope cues. Auditory processing deficits remained regardless of age, were observed in both unaided and aided conditions, and could not be attributed to differences in nonverbal IQ or attention between groups. However, better auditory processing in children with MMHL was predicted by better audiometric thresholds and, for aided tasks only, higher levels of maternal education. These results suggest that, as for adults with MMHL, children with MMHL may show deficits in frequency selectivity and sensitivity to TFS, but sensitivity to the envelope may remain intact.

Hierarchical micro/nanofibrous membranes of sustained releasing VEGF for periosteal regeneration

The periosteum plays a vital role in both development and injury healing process of bone. However, few researches have focused on artificial periosteum, which was also limited by the complexity on its construction and biological risks for clinical practice. In order to tackle this issue, inspired by the structural development of periosteum, we put forward a hierarchical micro/nanofibrous bionic periosteum with sustained releasing of VEGF as exogenous vascularized fibrous layer of periosteum to induce endogenous cambium layer in vivo for complete regeneration of periosteal and bone tissue, through collagen self-assembly and micro-sol electrospinning technologies. The VEGF encapsulated in hyaluronan-PLLA core-shell structure was demonstrated to be released in a durable way for angiogenesis in fibrous layer and bone defect area. Meanwhile, the self-assembly of collagen together with electrospun fibers contributed to a hierarchical micro/nanostructure which greatly mimicked the microenvironment of extracellular matrix to provide structural and biochemical cues for cell adhesion, proliferation and differentiation, and lead to the formation of cambium layer which mimicked the in-situ ossification manner as intramembranous ossification. As the motif of this study, the periosteal regeneration was characterized both by osteoblasts and periostin, which represented structural and molecular mechanisms respectively. Furthermore, the periosteal biomaterial proposed here possessed the superior abilities of scar inhibition, angiogenesis, osteogenesis to repair the bone defect in a uniform and rapid manner by inherent periosteal ossific mechanism involved in both intramembranous and endochondral ossification. Thus, the endogenous-exogenous combined bionic periosteum proved to be efficient and versatile in triggering periosteal and bone regeneration and hopefully supply a promising strategy for solving clinical issue.

The human amygdala disconnecting from auditory cortex preferentially discriminates musical sound of uncertain emotion by altering hemispheric weighting

How do humans discriminate emotion from non-emotion? The specific psychophysical cues and neural responses involved with resolving emotional information in sound are unknown. In this study we used a discrimination psychophysical-fMRI sparse sampling paradigm to locate threshold responses to happy and sad acoustic stimuli. The fine structure and envelope of auditory signals were covaried to vary emotional certainty. We report that emotion identification at threshold in music utilizes fine structure cues. The auditory cortex was activated but did not vary with emotional uncertainty. Amygdala activation was modulated by emotion identification and was absent when emotional stimuli were chance identifiable, especially in the left hemisphere. The right hemisphere amygdala was considerably more deactivated in response to uncertain emotion. The threshold of emotion was signified by a right amygdala deactivation and change of left amygdala greater than right amygdala activation. Functional sex differences were noted during binaural uncertain emotional stimuli presentations, where the right amygdala showed larger activation in females. Negative control (silent stimuli) experiments investigated sparse sampling of silence to ensure modulation effects were inherent to emotional resolvability. No functional modulation of Heschl’s gyrus occurred during silence; however, during rest the amygdala baseline state was asymmetrically lateralized. The evidence indicates changing hemispheric activation and deactivation patterns between the left and right amygdala is a hallmark feature of discriminating emotion from non-emotion in music.

Quality-guided video aesthetics assessment with social media context

Media aesthetic assessment is a key technique in computer vision, which is widely applied in computer game rendering, video/image classification. Low-level and high-level features fusion-based video aesthetic assessment algorithms have achieved impressive performance, which outperform photo- and motion-based algorithms, however, these methods only focus on aesthetic features of single-frame while ignore the inherent relationship between adjacent frames. Therefore, we propose a novel video aesthetic assessment framework, where structural cues among frames are well encoded. Our method consists of two components: aesthetic features extraction and structure correlation construction. More specifically, we incorporate both low-level and high-level visual features to construct aesthetic features, where salient regions are extracted for content understanding. Subsequently, we develop a structure correlation-based algorithm to evaluate the relationship among adjacent frames, where frames with similar structure property should have a strong correlation coefficient. Afterwards, a kernel multi-SVM is trained for video classification and high aesthetic video selection. Comprehensive experiments demonstrate the effectiveness of our method.

Characterization and in vivo study of decellularized aortic scaffolds using closed sonication system

ABSTRACTExtracellular matrix (ECM) based bioscaffolds prepared by decellularization has increasingly emerged in tissue engineering application because it has structural, biochemical, and biomechanical cues that have dramatic effects upon cell behaviors. Therefore, we developed a closed sonication decellularization system to prepare ideal bioscaffolds with minimal adverse effects on the ECM. The decellularization was achieved at 170 kHz of ultrasound frequency in 0.1% and 2% Sodium Dodecyl Sulphate (SDS) solution for 10 hours. The immersion treatment as control was performed to compare the decellularization efficiency with our system. Cell removal and ECM structure were determined by histological staining and biochemical assay. Biomechanical properties were investigated by the indentation testing to test the stiffness, a residual force and compression of bioscaffolds. Additionally, in vivo implantation was performed in rat to investigate host tissue response. Compared to native tissues, histological staining and biochemical assay confirm the absence of cellularity with preservation of ECM structure. Moreover, sonication treatment has not affected the stiffness [N/mm] and a residual force [N] of the aortic scaffolds except for compression [%] which 2% SDS significantly decreased compared to native tissues showing higher SDS has a detrimental effect on ECM structure. Finally, minimal inflammatory response was observed after 1 and 5 weeks of implantation. This study reported that the novelty of our developed closed sonication system to prepare ideal bioscaffolds for tissue engineering applications.

Graft Alignment Impacts the Regenerative Response of Skeletal Muscle after Volumetric Muscle Loss in a Rat Model

A key event in the etiology of volumetric muscle loss (VML) injury is the bulk loss of structural cues provided by the underlying extracellular matrix (ECM). To re-establish the lost cues, there is broad consensus within the literature supporting the utilization of implantable scaffolding. However, while scaffold based regenerative medicine strategies have shown potential, there remains a significant amount of outcome variability observed across the field. We suggest that an overlooked source of outcome variability is differences in scaffolding architecture. The goal of this study was to test the hypothesis that implant alignment has a significant impact on genotypic and phenotypic outcomes following the repair of VML injuries. Using a rat VML model, outcomes across three autograft implant treatment groups (aligned implants, 45° misaligned, and 90° misaligned) and two recovery time points (2 weeks and 12 weeks) were examined (n=6-8/group). At 2 weeks post-repair there were no significant differences in muscle mass and force recovery between the treatment groups, however we did observe a significant upregulation of MyoD (2.5 fold increase) and Pax7 (1.7 fold increase) gene expression as well as the presence of immature myofibers at the implant site for those animals repaired with aligned autografts. By 12 weeks post-repair, functional and structural differences between the treatment groups could be detected. Aligned autografts had significantly greater mass and force recovery (77±10% of normal) when compared to 45° and 90° misaligned autografts (64±10% and 61±11%, respectively). Examination of tissue structure revealed extensive fibrosis and a significant increase in non-contractile tissue area fraction for only those animals treated using misaligned autografts. When taken together, the results suggest that implant graft orientation has a significant impact on in-vivo outcomes and indicate that the effect of graft alignment on muscle phenotype may be mediated through genotypic changes to myogenesis and fibrosis at the site of injury and repair.

Acoustically Expressing Affect

Composers convey emotion through music by co-varying structural cues. Although the complex interplay provides a rich listening experience, this creates challenges for understanding the contributions of individual cues. Here we investigate how three specific cues (attack rate, mode, and pitch height) work together to convey emotion in Bach's Well Tempered-Clavier (WTC). In three experiments, we explore responses to (1) eight-measure excerpts and (2) musically “resolved” excerpts, and (3) investigate the role of different standard dimensional scales of emotion. In each experiment, thirty nonmusician participants rated perceived emotion along scales of valence and intensity (Experiments 1 & 2) or valence and arousal (Experiment 3) for 48 pieces in the WTC. Responses indicate listeners used attack rate, Mode, and pitch height to make judgements of valence, but only attack rate for intensity/arousal. Commonality analyses revealed mode predicted the most variance for valence ratings, followed by attack rate, with pitch height contributing minimally. In Experiment 2 mode increased in predictive power compared to Experiment 1. For Experiment 3, using “arousal” instead of “intensity” showed similar results to Experiment 1. We discuss how these results complement and extend previous findings of studies with tightly controlled stimuli, providing additional perspective on complex issues of interpersonal communication.

Exploiting the speech-gesture link to capture fine-grained prosodic prominence impressions and listening strategies

In this paper, we explore the possibility to gather perceptual impressions of prosodic prominence by exploiting the strong prosody-gesture link, i.e., by having listeners transform a perceptual impression into a motor movement, namely drumming, for two domains of prominence: word-level and syllable-level. A feasibility study reveals that such a procedure is indeed easily and speedily mastered by naïve listeners, but more difficult for word-level prominences. We furthermore examine whether “drummed” annotations are comparable to those gathered with more established annotation protocols based on cumulative naïve impressions and fine-grained expert ratings. These comparisons reveal high correspondences across all prominence annotation protocols, thus corroborating the general usefulness of the gestural approach. The analyses also reveal that all annotation protocols are strongly driven by structural linguistic considerations. We then use Random Forest Models to investigate the relative impact of signal and structural cues to prominence annotations. We find that expert ratings of prosodic prominence are guided comparatively more by structural concerns than those of naïve annotators, that word-level annotations are influenced more by structural linguistic cues than syllable-level ones, and that “drummed” annotations are driven least by structural cues. Lastly, we isolate two main listener strategies among our group of “drummers”, namely those integrating structural and signal cues to prominence, and those being guided predominantly by signal cues.

Bioinspired RGD-Engineered Bacteriophage Nanofiber Cues against Oxidative Stress.

Instructive tissue engineering biomaterials provide a vascular niche and protect oxidative stress in injured tissue. In this study, we exploited bioinspired bacteriophage nanofibers, previously recognized by their biochemical and structural cues inducing angiogenesis, as an antioxidant tissue engineering material. We demonstrated that topological cues of Arg-Gly-Asp (RGD)-engineered bacteriophage nanofibers provide angiogenic niches and cytoprotective functions against cellular oxidative stress with increased expression of antioxidant enzymes heme oxygenase-1 (HO-1) and NAD(P)H-quinone oxidoreductase 1 (NQO1) via the extracellular-signal-regulated kinase (ERK)-nuclear factor erythroid 2-related factor2 (Nrf2)-mediated signaling pathway, where a high density of RGD cues on the phage body support efficient interaction of cells with phage cues. These bioinspired RGD-engineered bacteriophage nanofibers can serve as a novel therapeutic platform for curing ischemic diseases.

Representative discovery of structure cues for coronary heart disease recognition based on quality assessment

Image recognition is an indispensable technique in computer vision, such as face recognition, vehicle recognition. It can be also widely used in medical research. Coronary heart disease recognition is still a big challenge due to artifacts or noise. In addition, recognizing coronary heart disease manually is a huge workload. So in this paper, we exploit representative structure cues for coronary heart disease recognition. More specifically, we first leverage Iterative Reconstruction (IR) algorithm to reduce the radiation dose during CT angiography acquisition. For structure cues discovery, we propose grid-based image segmentation algorithm, where each grid is represented by an according image quality score. High probability grid of disease cues corresponds to high quality score. Then, each training image is represented using quality score matrix. Afterward, we incorporate low-level features (grayscale and texture) with quality score matrix. Finally, image matching algorithm is proposed for structure cues discovery from test images. Experimental results demonstrate the effectiveness of our proposed method.

Estimation of 3D Category-Specific Object Structure: Symmetry, Manhattan and/or Multiple Images

Many man-made objects have intrinsic symmetries and often Manhattan structure. By assuming an orthographic or a weak perspective projection model, this paper addresses the estimation of 3D structures and camera projection using symmetry and/or Manhattan structure cues, for the two cases when the input is a single image or multiple images from the same category, e.g. multiple different cars from various viewpoints. More specifically, analysis on the single image case shows that Manhattan alone is sufficient to recover the camera projection and then the 3D structure can be reconstructed uniquely by exploiting symmetry. But Manhattan structure can be hard to observe from a single image due to occlusion. Hence, we extend to the multiple-image case which can also exploit symmetry but does not require Manhattan structure. We propose novel structure from motion methods for both rigid and non-rigid object deformations, which exploit symmetry and use multiple images from the same object category as input. We perform experiments on the Pascal3D+ dataset with either human labeled 2D keypoints or with 2D keypoints localized from a convolutional neural network. The results show that our methods which exploit symmetry significantly outperform the baseline methods.

Micropatterned conductive hydrogels as multifunctional muscle-mimicking biomaterials: Graphene-incorporated hydrogels directly patterned with femtosecond laser ablation

Multifunctional biomaterials that can provide physical, electrical, and structural cues to cells and tissues are highly desirable to mimic the important characteristics of native tissues and efficiently modulate cellular behaviors. Especially, electrically conductive biomaterials can efficiently deliver electrical signals to living systems; however, the production of conductive biomaterials presenting multiple cell interactive cues is still a great challenge. In this study, we fabricafed an electrically conductive, mechanically soft, and topographically active hydrogel by micropatterning a graphene oxide (GO)-incorporated polyacrylamide hydrogel (GO/PAAm) with femtosecond laser ablation (FLA) and subsequent chemical reduction. FLA parameters were optimized to efficiently produce distinct line patterns on GO/PAAm hydrogels to induce myoblast alignment and maturation. The line patterns distances (PD) were varied to have different topographies (20–80 μm PD). In vitro studies with C2C12 myoblasts revealed that the micopatterned hydrogels are superior to the unpatterned substrates in inducing myogenesis and myotube alignment. Reduced GO/PAAm with 50 μm PD, i.e., PD50/r(GO/PAAm), showed the best results among the various features for differentiation and myotube alignment. Electrical stimulation of myoblasts on the micropatterned conductive hydrogels further promoted the differentiation of myoblasts. In vivo implantation studies indicated good tissue compatibility of PD50/r(GO/PAAm) samples. Altogether, we successfully demonstrated that the micropatterned r(GO/PAAm) may offer multiple properties capable of positively affecting myoblast responses. This hydrogel may serve as an effective multifunctional biomaterial, which possesses the topography for cell alignment/maturation, mechanical properties of the native skeletal muscle tissue, and desirable electrical conductivity for delivering electrical signals to cells, for various biomedical applications such as muscle tissue scaffolds. Statement of SignificanceMicropatterned conductive hydrogels were created by polymerization of a graphene oxide-incorporated polyacrylamide hydrogel, micropatterning with femtosecond laser ablation, and chemical reduction, which can mimic important characteristics of native skeletal muscle tissues. The micropatterned conductive hydro-gels promoted myogenesis/alignment, enabled electrical stimulation of myoblasts, and displayed good tissue compatibility, which can therefore serve as a multifunctional biomaterial that is topographically active, mechanically soft, and electrically conductive for delivering multiple cell stimulating signals for potential skeletal muscle tissue engineering applications.

A collagen-based microwell migration assay to study NK-target cell interactions

Natural killer (NK) cell cytotoxicity in tissue is dependent on the ability of NK cells to migrate through the extracellular matrix (ECM) microenvironment. Traditional imaging studies of NK cell migration and cytotoxicity have utilized 2D surfaces, which do not properly reproduce the structural and mechanical cues that shape the migratory response of NK cells in vivo. Here, we have combined a microwell assay that allows long-term imaging and tracking of small, well-defined populations of NK cells with an interstitial ECM-like matrix. The assay allows for long-term imaging of NK–target cell interactions within a confined 3D volume. We found marked differences in motility between individual cells with a small fraction of the cells moving slowly and being confined to a small volume within the matrix, while other cells moved more freely. A majority of NK cells also exhibited transient variation in their motility, alternating between periods of migration arrest and movement. The assay could be used as a complement to in vivo imaging to study human NK cell heterogeneity in migration and cytotoxicity.

Variability of signal sequences in turn-taking exchanges induces agency attribution in 10.5-mo-olds

Infants' sensitivity to contingent reactivity as an indicator of intentional agency has been demonstrated by numerous referential gaze-following studies. Here we propose that variability of signal sequences in a turn-taking exchange provides an informative cue for infants to recognize interactions that may involve communicative information transfer between agents. Our experiment demonstrates that based on the abstract structural cue of variability of exchanged signal sequences, 10.5-mo-olds gaze-followed an entity's subsequent object-orienting action to fixate the same object. This gaze-following effect did not depend on the specific acoustic features of the sound signals produced. However, no orientation following to target was induced when the exchanged signal sequences were identical, or when only a single entity produced the variable sound sequences. These results demonstrate infants' early sensitivity to detect signal variability in turn-taking interactions as a relevant feature of communicative information transfer, which induces them to attribute intentional agency and communicative abilities to the participating entities. However, when no variability was present in the exchanged signals, or when the variable signal sequences were produced by a single entity alone, infants showed no evidence of attributing agency. In sum, we argue that perceiving contingent turn-taking exchange of variable signal sequences induce 10.5-mo-old preverbal infants to recognize such interactions as potentially involving communicative information transmission and attribute agency to the participating entities even if both the entities and the signals they produce are unfamiliar to them.

Anterior Chamber Angles Classification in Anterior Segment OCT Images via Multi-Scale Regions Convolutional Neural Networks.

Angle-closure glaucoma is one of the major causes of blindness in Asia. In this paper, we present a new approach for the classification of the anterior chamber angles into open, narrowed, and closure, in anterior segment optical coherence tomography (AS-OCT), by learning the manual annotations from gonioscopy, so as to further assist the assessment of angle-closure glaucoma. The proposed framework firstly localizes the anterior chamber angle region automatically, which is the primary structural image cue for clinically identifying glaucoma. Then three scales of cropped chamber angle images are fed into our Multi-Scale Regions Convolutional Neural Networks (MSRCNN) architecture, in which three parallel convolutional neural networks are applied to extract feature representations. Finally, the representations are stacked to fully-connected layer for glaucoma type classification. The proposed method is evaluated across a dataset of 9728 anterior chamber angle images, and the experimental results show that the proposed method outperforms existing state-of-the-art methods in applicability, effectiveness, and accuracy.

The effect of musicianship, contralateral noise, and ear of presentation on the detection of changes in temporal fine structure.

Musicians are better than non-musicians at discriminating changes in the fundamental frequency (F0) of harmonic complex tones. Such discrimination may be based on place cues derived from low resolved harmonics, envelope cues derived from high harmonics, and temporal fine structure (TFS) cues derived from both low and high harmonics. The present study compared the ability of highly trained violinists and non-musicians to discriminate changes in complex sounds that differed primarily in their TFS. The task was to discriminate harmonic (H) and frequency-shifted inharmonic (I) tones that were bandpass filtered such that the components were largely or completely unresolved. The effect of contralateral noise and ear of presentation was also investigated. It was hypothesized that contralateral noise would activate the efferent system, helping to preserve the neural representation of envelope fluctuations in the H and I stimuli, thereby improving their discrimination. Violinists were significantly better than non-musicians at discriminating the H and I tones. However, contralateral noise and ear of presentation had no effect. It is concluded that, compared to non-musicians, violinists have a superior ability to discriminate complex sounds based on their TFS, and this ability is unaffected by contralateral stimulation or ear of presentation.

Sound, structure and meaning: The bases of prominence ratings in English, French and Spanish

This study tests the influence of acoustic cues and non-acoustic contextual factors on listeners’ perception of prominence in three languages whose prominence systems differ in the phonological patterning of prominence and in the association of prominence with information structure—English, French and Spanish. Native speakers of each language performed an auditory rating task to mark prominent words in samples of conversational speech under two instructions: with prominence defined in terms of acoustic or meaning-related criteria. Logistic regression models tested the role of task instruction, acoustic cues and non-acoustic contextual factors in predicting binary prominence ratings of individual listeners. In all three languages we find similar effects of prosodic phrase structure and acoustic cues (F0, intensity, phone-rate) on prominence ratings, and differences in the effect of word frequency and instruction. In English, where phrasal prominence is used to convey meaning related to information structure, acoustic and meaning criteria converge on very similar prominence ratings. In French and Spanish, where prominence plays a lesser role in signaling information structure, phrasal prominence is perceived more narrowly on structural and acoustic grounds. Prominence ratings from untrained listeners correspond with ToBI pitch accent labels for each language. Distinctions in ToBI pitch accent status (nuclear, prenuclear, unaccented) are reflected in empirical and model-predicted prominence ratings. In addition, words with a ToBI pitch accent type that is typically associated with contrastive focus are more likely to be rated as prominent in Spanish and English, but no such effect is found for French. These findings are discussed in relation to probabilistic models of prominence production and perception.

Filming the airways

Innate Lymphoid Cells Group 2 innate lymphoid cells (ILC2s) are key drivers of immune responses in the lung. Puttur et al. used an interleukin-13 (IL-13) reporter mouse strain to visualize migration of ILC2s in allergic airway inflammation. ILC2s exhibited dynamic ameboid-like movement in response to IL-33. IL-3 induced up-regulation of chemokine receptor 8 on ILC2s, which promoted their homing to deposits of chemokine ligand 8 within the airways. Collagen-I, a component of the extracellular matrix (ECM), played a role in directly regulating ILC2 cell migration. Thus, structural cues from the ECM work in conjunction with immune mediators to influence immune cell functions in tissues. Sci. Immunol. 4 , eaav7638 (2019).

Biomimetic cartilage scaffold with orientated porous structure of two factors for cartilage repair of knee osteoarthritis

A dual-layer biomimetic cartilage scaffold was prepared by mimicking the structural design, chemical cues and mechanical characteristics of mature articular cartilage. The surface layer was made from collagen (COL), chitosan (CS) and hyaluronic acid sodium (HAS). The transitional layer with microtubule array structure was prepared with COL, CS and silk fibroin (SF). The PLAG microspheres containing kartogenin (KGN) and the polylysine-heparin sodium nanoparticles containing TGF-β1 (TPHNs) were constructed for the surface, transitional layer, respectively. The SEM result showed that the dual-layer composite scaffold had a double structure similar to natural cartilage. The vitro biocompatibility experiment showed that the biomimetic cartilage scaffold with orientated porous structure was more conducive to the proliferation and adhesion of BMSCs. A rabbit KOA cartilage defect model was established and biomimetic cartilage scaffolds were implanted in the defect area. Compared with the surface layer and transitional layer scaffolds group, the results of dual-layer biomimetic cartilage scaffold group showed that the defects had been completely filled, the boundary between new cartilage and surrounding tissue was difficult to identify, and the morphology of cells in repair tissue was almost in accordance with the normal cartilage after 16 weeks. All those results indicated that the biomimetic cartilage scaffold could effectively repair the defect of KOA, which is related to the fact that the scaffold could guide the morphology, orientation, and proliferation and differentiation of BMSCs. This work could potentially lead to the development of multilayer scaffolds mimicking the zonal organization of articular cartilage.