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This article explores the expansion of the genetic alphabet through the creation of unnatural nucleobase pairs. These new nucleobase pairs can be incorporated into DNA, allowing for the generation of unique functional proteins. The article discusses the development of xeno-nucleic acids (XNAs) and the use of charge-transfer interactions and click chemistry to design synthetic nucleobases. It also explores the synthesis and potential applications of C-nucleosides, as well as the design and applications of unnatural nucleobases in DNA and RNA. The researchers successfully created a semi-synthetic organism with an expanded genetic alphabet and investigated the stability and pairing selectivity of abasic DNA duplexes containing unnatural nucleobases. The article also discusses the use of fluorescent nucleosides in detecting DNA lesions and the potential applications of chimeric DNA duplexes in various fields. The research provides valuable insights for researchers interested in genetic alphabet expansion and the study of nucleic acids and proteins. [Extracted from the article]

Dissimilar-weld-fabrications are created to capture privilege of certain attributes of each component to enhance the potential of overall structure. Induced residual stress owing to non-uniform thermal cycle, strain developed by virtue of metallurgicaltransformation, and dramatic difference in thermo-physical and thermo-mechanical property, proved to be a major drawback and limits application certainly. Present study includes amalgamation of material-characterization and numerical-modelling to overcome aforementioned issue. The 17-4 precipitation-hardened steel was joined with SS316 steel by CO2 laser-welding technique using different-heat-input. It is noticed that the distribution and amount of d-ferrite controls the on-site behavior relating to thermal stability, microstructural characteristics and residual stress generation. This work is attempted to understand thermal behavior as well as its correlation with d-ferrite formation and residual stress distribution. Sequential-coupled-thermo-mechanical model proposed to developed for dissimilar weld joints at different process conditions. Finally, the interrelation between microstructure and the typical pattern of residual stress believed to be investigated systematically. [ABSTRACT FROM AUTHOR]

Arpan Guha Mazumder,1,2 Swarnadip Chatterjee,3 Saunak Chatterjee,1 Juan Jose Gonzalez,4 Swarnendu Bag,5 Sambuddha Ghosh,6 Anirban Mukherjee,7 Jyotirmoy Chatterjee1 1Multimodal Imaging and Computing for Theranostics Laboratory, School of Medical Science and Technology, Indian Institute of Technology-Kharagpur, Kharagpur, West Bengal, India; 2Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Advanced Technology Development Centre, Indian Institute of Technology-Kharagpur, Kharagpur, West Bengal, India; 4Department of Computer and Electrical Engineering, Rice University, Houston, TX, USA; 5Department of Biotechnology, National Institute of Technology Sikkim, Ravangla Sub-Division, South Sikkim, 6Department of Ophthalmology, Calcutta National Medical College and Hospital, Kolkata, West Bengal, 7Department of Electrical Engineering, Indian Institute of Technology-Kharagpur, Kharagpur, West Bengal, India Introduction: Image-based early detection for diabetic retinopathy (DR) needs value addition due to lack of well-defined disease-specific quantitative imaging biomarkers (QIBs) for neuroretinal degeneration and spectropathological information at the systemic level. Retinal neurodegeneration is an early event in the pathogenesis of DR. Therefore, development of an integrated assessment method for detecting neuroretinal degeneration using spectropathology and QIBs is necessary for the early diagnosis of DR. Methods: The present work explored the efficacy of intensity and textural features extracted from optical coherence tomography (OCT) images after selecting a specific subset of features for the precise classification of retinal layers using variants of support vector machine (SVM). Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy were also performed to confirm the spectropathological attributes of serum for further value addition to the OCT, fundoscopy, and fluorescein angiography (FA) findings. The serum metabolomic findings were also incorporated for characterizing retinal layer thickness alterations and vascular asymmetries.Results: Results suggested that OCT features could differentiate the retinal lesions indicating retinal neurodegeneration with high sensitivity and specificity. OCT, fundoscopy, and FA provided geometrical as well as optical features. NMR revealed elevated levels of ribitol, glycerophosphocholine, and uridine diphosphate N-acetyl glucosamine, while the FTIR of serum samples confirmed the higher expressions of lipids and β-sheet-containing proteins responsible for neoangiogenesis, vascular fragility, vascular asymmetry, and subsequent neuroretinal degeneration in DR.Conclusion: Our data indicated that disease-specific spectropathological alterations could be the major phenomena behind the vascular attenuations observed through fundoscopy and FA, as well as the variations in the intensity and textural features observed in OCT images. Finally, we propose a model that uses spectropathology corroborated with specific QIBs for detecting neuroretinal degeneration in early diagnosis of DR. Keywords: diabetic retinopathy, quantitative imaging biomarkers, QIBs, spectropathology, neuroretinal degeneration, optical coherence tomography, OCT, support vector machine, SVM

Kinsuk Das,1 AP Madhusoodan,1 Bhabesh Mili,1 Ajay Kumar,2 AC Saxena,3 Kuldeep Kumar,1 Mihir Sarkar,1 Praveen Singh,4 Sameer Srivastava,5 Sadhan Bag1 1Division of Physiology and Climatology, 2Biochemistry and Food Science Section, 3Division of Surgery, 4Biophysics, Electron Microscopy and Instrumentation Section, 5Division of Veterinary Biotechnology, Indian Council of Agricultural Research – Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh, India Abstract: In the field of regenerative medicine, numerous potential applications of mesenchymal stem cells (MSCs) can be envisaged, due to their ability to differentiate into a range of tissues on the basis of the substrate on which they grow. With the advances in nanotechnology, carbon nanotubes (CNTs) have been widely explored for use as cell culture substrate in tissue engineering applications. In this study, canine bone marrow-derived MSCs were considered as the cellular model for an in vitro study to elucidate the collective cellular processes, using three different varieties of thin films of functionalized carbon nanotubes (COOH-single-walled CNTs [SWCNTs], COOH-multiwalled CNTs [MWCNTs] and polyethylene glycol [PEG]-SWCNTs), which were spray dried onto preheated cover slips. Cells spread out better on the CNT films, resulting in higher cell surface area and occurrence of filopodia, with parallel orientation of stress fiber bundles. Canine MSCs proliferated at a slower rate on all types of CNT substrates compared to the control, but no decline in cell number was noticed during the study period. Expression of apoptosis-associated genes decreased on the CNT substrates as time progressed. On flow cytometry after AnnexinV-fluorescein isothiocyanate/propidium iodide (PI) staining, total number of apoptotic and necrotic cells remained lower in COOH-functionalized films compared to PEG-functionalized ones. Collectively, these results indicate that COOH-MWCNT substrate provided an environment of low cytotoxicity. Canine MSCs were further induced to differentiate along osteogenic, chondrogenic, and neuronal lineages by culturing under specific differentiation conditions. The cytochemical and immunocytochemical staining results, as well as the expression of the bone marker genes, led us to hypothesize that the COOH-MWCNT substrate acted as a better cue, accelerating the osteogenic differentiation process. However, while chondrogenesis was promoted by COOH-SWCNT, neuronal differentiation was promoted by both COOH-SWNCT and COOH-MWCNT. Taken together, these findings suggest that COOH-functionalized CNTs represent a promising scaffold component for future utilization in the selective differentiation of canine MSCs in regenerative medicine. Keywords: canine MSCs, CNT films, cellular behavior, cytocompatibility, differentiation

Intermetallic formation during dissimilar welding of Inconel and stainless steel significantly hinders producing sound-quality weld. In the present work, a high-power CO2 laser welding system is employed to join Inconel 718 and AISI 316L stainless steel without using any filler materials. The finite element based thermal model provides the temperature distribution in the weld zone and consequently the solidification parameters (G/R and G.R). The micro-segregation and intermetallic formation in laser welding are correlated with these solidification parameters. The segregation of principal alloying elements triggers the formation of intermetallic phases during solidification. The presence of various phases like Laves, NbC, and TiC in the fusion zone reduces with increase in heat input. The amount of these intermetallic phases present in the weld zone is estimated by XRD analysis. With an increase in heat input, the mode of solidification changes from columnar to equiaxed dendrites that is characterized at reduced value of solidification parameter (G/R). The intermetallic Laves particle diminishes significantly (more than 90%) with a reduction of G/R parameter. In equiaxed dendrites, the segregation and formation of these secondary particles reduces to more than 40% compared to the columnar dendritic structure. Overall, the reduction in the intermetallic particles improves the joint efficiency up to 100% with an elongation of 14.2% for the equiaxed structure of the laser welding system. Graphical abstract [ABSTRACT FROM AUTHOR]