A Phase-Preserving Focusing Technique for TOPS Mode SAR Raw Data Based on Conventional Processing Methods.

We present a new solution for the phase-preserving focusing of synthetic aperture radar (SAR) raw data acquired through the Terrain Observation with Progressive Scan (TOPS) mode. The proposed algorithm consists of a first interpolation stage of the TOPS raw data, which takes into account the Doppler Centroid frequency variations due to the azimuth antenna steering function, and allows us to unfold the azimuth spectra of the TOPS raw data. Subsequently, the interpolated signals are processed by using conventional phase-preserving SAR focusing methods that exploit frequency domain and spectral analyses algorithms, which are extensively used to efficiently process Stripmap and ScanSAR data. Accordingly, the developed focusing approach is easy to implement. In particular, the presented focusing approach exploits one of the available frequency domain Stripmap processing techniques. The only modification is represented by the inclusion, within the 2D frequency domain focusing step, of a spurious azimuth chirp signal with a properly selected azimuthal rate. This allows us to efficiently carry out the TOPS azimuth focusing through the SPECAN method. Furthermore, an important aspect of this algorithm is the possibility to easily achieve a constant and tunable output azimuth pixel size without any additional computing time; this is a remarkable feature with respect to the full-aperture TOPS-mode algorithms available in the existing literature. Moreover, although tailored on Sentinel-1 (S1) raw data, the proposed algorithm can be easily extended to process data collected through the TOPS mode by different radar sensors. The presented experimental results have been obtained by processing real Sentinel-1 raw data and confirm the effectiveness of the proposed algorithm.

Osteochondral regeneration with a tri-layered biomimetic resorbable scaffold: In vivo study in a sheep model up to 12 months of follow-up.

The treatment of osteochondral joint lesions requires the regeneration of both articular cartilage and subchondral bone tissue. Scaffold-based strategies aimed at mimicking the native osteochondral structure have been explored with mixed results. The aim of this study was to evaluate the regenerative potential of a tri-layered osteochondral cell-free scaffold in a large animal model at both 6 and 12 months of follow-up. Bilateral critical-sized osteochondral defects were created in 22 sheep. One defect was filled with the scaffold, whereas the contralateral was left empty. The repair tissue quality was evaluated at 6 and 12 months of follow-up in terms of macroscopic appearance, histology, trabecular bone formation, and inflammation grade. The mean global ICRS II score in the scaffold and control groups was 41 ± 11 vs 30 ± 6 at 6 months (p = 0.004) and 54 ± 13 vs 37 ± 11 at 12 months (p = 0.002), respectively. A higher percentage of bone was found in the treatment group compared to controls both at 6 (BV/TV 48.8 ± 8.6 % vs 37.4 ± 9.5 %, respectively; p < 0.001) and 12 months (BV/TV 51.8 ± 8.8 % vs 42.1 ± 12.6 %, respectively; p = 0.023). No significant levels of inflammation were seen. These results demonstrated the scaffold safety and potential to regenerate both cartilage and subchondral tissues in a large animal model of knee osteochondral lesions.

Lung-to-Heart Nano-in-Micro Peptide Promotes Cardiac Recovery in a Pig Model of Chronic Heart Failure.

BACKGROUND: The lack of disease-modifying drugs is one of the major unmet needs in patients with heart failure (HF). Peptides are highly selective molecules with the potential to act directly on cardiomyocytes. However, a strategy for effective delivery of therapeutics to the heart is lacking. OBJECTIVES: In this study, the authors sought to assess tolerability and efficacy of an inhalable lung-to-heart nano-in-micro technology (LungToHeartNIM) for cardiac-specific targeting of a mimetic peptide (MP), a first-in-class for modulating impaired L-type calcium channel (LTCC) trafficking, in a clinically relevant porcine model of HF. METHODS: Heart failure with reduced ejection fraction (HFrEF) was induced in Göttingen minipigs by means of tachypacing over 6 weeks. In a setting of overt HFrEF (left ventricular ejection fraction [LVEF] 30% ± 8%), animals were randomized and treatment was started after 4 weeks of tachypacing. HFrEF animals inhaled either a dry powder composed of mannitol-based microparticles embedding biocompatible MP-loaded calcium phosphate nanoparticles (dpCaP-MP) or the LungToHeartNIM only (dpCaP without MP). Efficacy was evaluated with the use of echocardiography, invasive hemodynamics, and biomarker assessment. RESULTS: DpCaP-MP inhalation restored systolic function, as shown by an absolute LVEF increase over the treatment period of 17% ± 6%, while reversing cardiac remodeling and reducing pulmonary congestion. The effect was recapitulated ex vivo in cardiac myofibrils from treated HF animals. The treatment was well tolerated, and no adverse events occurred. CONCLUSIONS: The overall tolerability of LungToHeartNIM along with the beneficial effects of the LTCC modulator point toward a game-changing treatment for HFrEF patients, also demonstrating the effective delivery of a therapeutic peptide to the diseased heart.

Effectiveness of BMP-2 and PDGF-BB Adsorption onto a Collagen/Collagen-Magnesium-Hydroxyapatite Scaffold in Weight-Bearing and Non-Weight-Bearing Osteochondral Defect Bone Repair: In Vitro, Ex Vivo and In Vivo Evaluation.

Despite promising clinical results in osteochondral defect repair, a recently developed bi-layered collagen/collagen-magnesium-hydroxyapatite scaffold has demonstrated less optimal subchondral bone repair. This study aimed to improve the bone repair potential of this scaffold by adsorbing bone morphogenetic protein 2 (BMP-2) and/or platelet-derived growth factor-BB (PDGF-BB) onto said scaffold. The in vitro release kinetics of BMP-2/PDGF-BB demonstrated that PDGF-BB was burst released from the collagen-only layer, whereas BMP-2 was largely retained in both layers. Cell ingrowth was enhanced by BMP-2/PDFG-BB in a bovine osteochondral defect ex vivo model. In an in vivo semi-orthotopic athymic mouse model, adding BMP-2 or PDGF-BB increased tissue repair after four weeks. After eight weeks, most defects were filled with bone tissue. To further investigate the promising effect of BMP-2, a caprine bilateral stifle osteochondral defect model was used where defects were created in weight-bearing femoral condyle and non-weight-bearing trochlear groove locations. After six months, the adsorption of BMP-2 resulted in significantly less bone repair compared with scaffold-only in the femoral condyle defects and a trend to more bone repair in the trochlear groove. Overall, the adsorption of BMP-2 onto a Col/Col-Mg-HAp scaffold reduced bone formation in weight-bearing osteochondral defects, but not in non-weight-bearing osteochondral defects.

Surface ruptures and off-fault deformation of the October 2016 central Italy earthquakes from DInSAR data.

Large magnitude earthquakes produce complex surface deformations, which are typically mapped by field geologists within the months following the mainshock. We present detailed maps of the surface deformation pattern produced by the M. Vettore Fault System during the October 2016 earthquakes in central Italy, derived from ALOS-2 SAR data, via DInSAR technique. On these maps, we trace a set of cross-sections to analyse the coseismic vertical displacement, essential to identify both surface fault ruptures and off-fault deformations. At a local scale, we identify a large number of surface ruptures, in agreement with those observed in the field. At a larger scale, the inferred coseismic deformation shows a typical long-wavelength convex curvature of the subsiding block, not directly recognizable in the field. The detection of deformation patterns from DInSAR technique can furnish important constraints on the activated fault segments, their spatial distribution and interaction soon after the seismic events. Thanks to the large availability of satellite SAR acquisitions, the proposed methodological approach can be potentially applied to worldwide earthquakes (according to the environmental characteristics of the sensed scene) to provide a wider and faster picture of surface ruptures. Thus, the derived information can be crucial for emergency management by civil protection and helpful to drive and support the geological field surveys during an ongoing seismic crisis.

Inhalable Microparticles Embedding Calcium Phosphate Nanoparticles for Heart Targeting: The Formulation Experimental Design.

Inhalation of Calcium Phosphate nanoparticles (CaPs) has recently unmasked the potential of this nanomedicine for a respiratory lung-to-heart drug delivery targeting the myocardial cells. In this work, we investigated the development of a novel highly respirable dry powder embedding crystalline CaPs. Mannitol was selected as water soluble matrix excipient for constructing respirable dry microparticles by spray drying technique. A Quality by Design approach was applied for understanding the effect of the feed composition and spraying feed rate on typical quality attributes of inhalation powders. The in vitro aerodynamic behaviour of powders was evaluated using a medium resistance device. The inner structure and morphology of generated microparticles were also studied. The 1:4 ratio of CaPs/mannitol led to the generation of hollow microparticles, with the best aerodynamic performance. After microparticle dissolution, the released nanoparticles kept their original size.

Hyalograft C: hyaluronan-based scaffolds in tissue-engineered cartilage.

Articular cartilage injuries have poor reparative capability and, if left untreated, may progress to osteo-arthritis. Unsatisfactory results with conventional treatment methods have prompted the development of innovative solutions including the use of cell transplantations, with or without a supporting scaffold. Tissue engineering combines cells, scaffolds and bio-active factors, which represents one of the most promising approaches for the restoration of damaged tissues. Available today, hyaluronan, also known as hyaluronic acid, is a natural glycosaminoglycan present in all soft tissues of higher organisms and in particularly high concentrations in the extracellular matrix of articular cartilage and in the mesenchyme during embryonic development in which it plays a number of biological functions, not only as a structural component but as an informational molecule as well. Moreover, hyaluronan can be manufactured in a variety of physical forms including hydrogels, sponges, fibres and fabrics allowing to develop a variety of hyaluronan-based scaffolds. This review will present both theoretical and experimental evidences that led to the development of Hyalograft C, an exploitation of hyaluronic acid technology and a tissue engineering approach for the resolution of articular cartilage defects.

Maturation of tissue engineered cartilage implanted in injured and osteoarthritic human knees.

The regeneration of damaged organs requires that engineered tissues mature when implanted at sites of injury or disease. We have used new analytic techniques to determine the extent of tissue regeneration after treatment of knee injury patients with a novel cartilage tissue engineering therapy and the effect of pre-existing osteoarthritis on the regeneration process. We treated 23 patients, with a mean age of 35.6 years, presenting with knee articular cartilage defects 1.5 cm2 to 11.25 cm2 (mean, 5.0 cm2) in area. Nine of the patients had X-ray evidence of osteoarthritis. Chondrocytes were isolated from healthy cartilage removed at arthroscopy. The cells were cultured for 14 days, seeded onto esterified hyaluronic acid scaffolds (Hyalograft C), and grown for a further 14 days before implantation. A second-look biopsy was taken from each patient after 6 to 30 months (mean, 16 months). After standard histological analysis, uncut tissue was further analyzed using a newly developed biochemical protocol involving digestion with trypsin and specific, quantitative assays for type II collagen, type I collagen, and proteoglycan, as well as mature and immature collagen crosslinks. Cartilage regeneration was observed as early as 11 months after implantation and in 10 out of 23 patients. Tissue regeneration was found even when implants were placed in joints that had already progressed to osteoarthrosis. Cartilage injuries can be effectively repaired using tissue engineering, and osteoarthritis does not inhibit the regeneration process.

Tissue engineering of white adipose tissue using hyaluronic acid-based scaffolds. I: in vitro differentiation of human adipocyte precursor cells on scaffolds.

BACKGROUND AND AIM OF THE STUDY: Reconstruction of soft tissue defects is a challenge in plastic surgery and there is clinical need for adequate solutions. Aim of this study was to develop a biohybrid construct consisting of hyaluronic acid-based scaffolds and human adipocyte precursor cells as a soft tissue filler. METHODS: Human adipocyte precursor cells were obtained by collagenase digestion of adipose tissue samples and seeded on hyaluronic acid-based spongy scaffolds of various degrees of esterification and pore size using different techniques. After cell attachment, adipose differentiation was induced by defined adipogenic factors under serum-free culture conditions. RESULTS: Among the five different scaffold types under investigation the highest cell attachment rate was observed for the HYAFF scaffold with 100% esterification and a mean pore size of 400microm (HYAFF 11lp). For inoculation of human adipocyte precursor cells on hyaluronic acid-based scaffolds a "drop-on" technique and low-pressure centrifugation using a Speed Vac airfuge were compared. With respect to efficacy, cell distribution and simpleness the drop-on method proved to be the method of choice. In a serum-free medium supplemented with 66nM insulin, 100nM cortisol and 1microg/ml troglitazone a substantial proportion of cells underwent adipose differentiation as assessed by lipid accumulation and emergence of glycerol-3-phosphate dehydrogenase activity, a lipogenic marker enzyme. CONCLUSION: Hyaluronic acid-based scaffolds appear to be a suitable three-dimensional carrier for the culture and in vitro differentiation of human adipocyte precursor cells.