02769nas a2200229   4500008004100000245012000041210006900161260000800230300001100238490000800249520195200257653002702209653001502236653003002251653002102281100002102302700001702323700002602340700002002366700002702386856012602413       2024                        eng d00aBiodegradable and 3D printable lysine functionalized polycaprolactone scaffolds for tissue engineering applications0 aBiodegradable and 3D printable lysine functionalized polycaprola  cMAY  a2138160 v1593 a<p>
	Tissue engineering (TE) has sparked interest in creating scaffolds with customizable properties and functional bioactive sites. However, due to limitations in medical practices and manufacturing technologies, it is challenging to replicate complex porous frameworks with appropriate architectures and bioactivity in vitro. To address these challenges, herein, we present a green approach that involves the amino acid (L-lysine) initiated polymerization of epsilon-caprolactone (CL) to produce modified polycaprolactone (PCL) with favorable active sites for TE applications. Further, to better understand the effect of morphology and porosity on cell attachment and proliferation, scaffolds of different geometries with uniform and interconnected pores are designed and fabricated, and their properties are evaluated in comparison with commercial PCL. The scaffold morphology and complex internal micro-architecture are imaged by micro-computed tomography (micro-CT), revealing pore size in the range of similar to 300-900 mu m and porosity ranging from 30 to 70 %, while based on the geometry of scaffolds the compressive strength varied from 143 +/- 19 to 214 +/- 10 MPa. Additionally, the degradation profiles of fabricated scaffolds are found to be influenced by both the chemical nature and product design, where Lys-PCL-based scaffolds with better porosity and lower crystallinity degraded faster than commercial PCL scaffolds. According to in vitro studies, Lys-PCL scaffolds have produced an environment that is better for cell adhesion and proliferation. Moreover, the scaffold design affects the way cells interact; Lys-PCL with zigzag geometry has demonstrated superior in vitro vitality (&gt;90 %) and proliferation in comparison to other designs. This study emphasizes the importance of enhancing bioactivity while meeting morphology and porosity requirements in the design of scaffolds for tissue engineering applications.</p>
10aAdditive manufacturing10aAmino acid10aMicro-computed tomography10aPolycaprolactone1 aNaik, Sonali, S.1 aTorris, Arun1 aChoudhury, Namita, R.1 aDutta, Naba, K.1 aNair, Kiran, Sukumaran  uhttps://library.ncl.res.in/content/biodegradable-and-3d-printable-lysine-functionalized-polycaprolactone-scaffolds-tissue02747nas a2200241   4500008004100000022001400041245009500055210006900150260000800219490000800227520191500235653002702150653002502177653002402202653002002226653003702246653003002283100001902313700001402332700001702346700002202363856012002385       2026                        eng d  a1087-135700aStrategies to mitigate interlayer porosity in the laser-directed energy deposition process0 aStrategies to mitigate interlayer porosity in the laserdirected   cJUN0 v1483 a<p>
	Laser-directed energy deposition (L-DED) offers unique advantages for fabricating large-scale metallic components and repairing high-value parts. However, recurring interlayer porosity, particularly while depositing targeted geometry and dimensions, remains a major limitation affecting structural integrity. In this study, systematic deposition strategies were developed to mitigate interlayer porosity by controlling track overlap and optimizing energy apportionment, the two aspects that have not been reported together in previous L-DED studies. Experimental analysis showed that increasing the percentage overlap from 30% to 40% significantly reduced porosity, whereas defining the overlap based on the full width at half maximum (FWHM) provided a more geometry-representative approach. A 30% FWHM overlap was found to be most effective in disrupting periodic porosity recurrence. Additionally, introducing skewed track alignment minimized valley-to-valley overlap across layers, further reducing defect formation. Complementary to geometric strategies, interlayer laser polishing with circular and line beams facilitated pore closure while refining the interlayer microstructure. A key novelty of this work lies in coupling overlap optimization with energy apportionment between powder and substrate, achieved by adjusting the stand-off distance (SoD), which is quantified by a unique experimental approach. This enhanced molten pool flow and ensured improved remelting of the previously deposited layer, which, when combined with a 30% FWHM overlap, effectively eliminated visible interlayer porosity, validated by micro-computed tomography analysis. The integrated approach of optimized overlap, energy apportionment, and interlayer polishing enabled defect-free fabrication of straight walls as well as complex turbine blade profiles, while simultaneously enhancing strength and ductility.</p>
10aAdditive manufacturing10aenergy apportionment10ainterlayer porosity10alaser polishing10alaser-directed energy deposition10aMicro-computed tomography1 aJha, Arkajyoti1 aRamji, M.1 aTorris, Arun1 aGopinath, Muvvala  uhttps://library.ncl.res.in/content/strategies-mitigate-interlayer-porosity-laser-directed-energy-deposition-process