Pulsed laser processing of dielectric materials

The thesis investigates the wavelength dependent laser ablation in dielectric materials used for the fabrication of high density Printed Circuit Boards (PCBs) in the electronics industry. Here the market for consumer and industrial products of ever-rising complexity has led to a demand for increased miniaturisation and low costs of multi- level printed circuit boards (PCBs) interconnected by microvias, which electrically connect the various circuit layers. Laser machining offers a potential solution to this need. The main objective of the research is to investigate the wavelength-dependence of the laser machining/drilling efficiency of two important sets of PCB materials, categorised as Organics and Ceramics using a carbon dioxide laser which can be tuned across its emission spectrum in the 9pm -II pin spectral region.. The organics include commercially available electronic materials with trade names such as Kapton, Arlon, FR4 and RCC and the ceramics materials studied are alumina and low temperature co- fired ceramic (LTCC). The aim is to determine the optimum laser wavelength for maximum processing efficiency i. e. to find the wavelength where the laser parameters are best matched to the optical, thermal and mechanical properties of each of the materials. A C02 laser machining system was constructed which incorporated a novel laser source developed in the research programmes. The laser source was a MOPA system with a line-tuneable cw oscillator and a five pass power planar waveguide rf discharge-excited power operating in the so-called enhanced power regime to produce maximum peak power. An Acousto-optic modulator between the master oscillator and the amplifier allowed convenient control of pulse amplitude and duration. The system enabled the wavelength dependent studies on the wavelength and pulse energy dependence of the laser ablation properties (e. g. ablation threshold fluence and ablation rates) - to derive the so-called 'ablation spectrum' of the selected materials A comparison is made of the wavelength dependence of ablation with the room temperature absorption spectrum measured for each material using ellipsometry. It was observed that the 'ablation spectrum' information does not always appear to match the simple expectations derived from the room temperature 'absorption spectrum' of the material. This disparity in results is likely due to the change of absorption properties of material because of rise in temperature, chemical decomposition or melting of material during ablation. However, the room temperature absorption spectrum (while not adequate alone), did provide a useful guide to the selection of a sub-set of the 40+ lines that would otherwise have to be studied. The results may be of direct application in the electronics industry to increase the efficiency of laser machinin

Cell mechanotransduction machinery, and signaling defects: small tools and nano-bio interface for influential regenerative remedies

© 2021 The Authors. Published by Longdom Publishing. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://www.longdom.org/open-access/cell-mechanotransduction-machinery-and-cell-signaling-defects-small-tools-and-nanobio-interface-for-influential-regenera.pdfDesigning nanotools and devices offers a wider platform having high therapeutic claims for the discovery of drug discovery and promoting cellular events including cell motility, signaling pathways, cellular proliferation, cell physiology, apoptosis, and microenvironmental conditions during tissue engineering and regeneration. To enhance cellular environment in a physical and chemical context, the nanotools having remedies to care for the endothelial matrix during various cellular processes and mechanisms (nutrient transport, cell health, cellular interactions, differentiation, and proliferation). The influential regenerative remedies were also transported by drug delivery tools and devices for enhancing biophysical interactions with multiple mechanoresponsive that further support healing. Therefore, the small tools and nano-bio interface were also applied for stimulation and rejuvenation. The role of the Wnt/β-Catenin pathway, growth factor-β (TGF-β) signaling, inflammasome, IL-1β, cytokine, cadherin, and Ca2+dependent cell-cell adhesion proteins in the regeneration were underlined and highlighted. The elucidation of interlinked signaling pathways of cellular events offers a new approach for developing novel therapeutic remedies and emerged as new concepts in tissue regeneration and repair. Cell damage tempted injury leads to apoptosis, autophagy, and necroptosis via different processes

Cytokine storm and signaling pathways: pathogenesis of SARS‐CoV‐2 infection, managing and treatment strategies

© 2021 The Authors. Published by Biomedical Research Network. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://biomedres.us/pdfs/BJSTR.MS.ID.005715.pdfCoronavirus disease is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to date, no novel treatment so far is available to cure it. Therefore, it is an urgent need to develop an effective treatment for the patients who are suffering from it. Naturally, when SARS-CoV-2 infection transpired, the nervous system of the body of the patient responds to it immediately by activating the immune cells that further triggered inflammation to counter it. In this fight, the cytokine storms originated in the host cells and it becomes life-threatening and finally, in absence of treatment, it eventually results in death. Therefore, the dysregulation of inflammatory immune responses, by any mean can improve the health of the patients. It was evident that most patients who were suffering from severe SARS-CoV-2, exhibit a high level of pro-inflammatory cytokines, including interferon (IFN)-α, and interleukin (IL)-1β. In these circumstances, an immunotherapeutic strategy will be effective for the suppression of cytokine storms and will prevent any respiratory failure in the patients

Experimental and simulation study of the effect of cut-out defect in carbon fibres twill weave composite

This is an accepted manuscript of an article published by Springer in SN Applied Sciences on 03/05/2020, available online: https://doi.org/10.1007/s42452-020-2605-7 The accepted version of the publication may differ from the final published version.The automated fibre placement (AFP) is an effective manufacturing process that produces a large complex structure with high quality at low secondary waste. Although, the AFP is highly accurate and reproducible and very common in the aerospace application, break and cut-out defect in the plies are inevitable. In this study, we have investigated 4 different types of geometrical cut-out defect that have an equal area (38.4 mm2) that cut from identical locations in the specimen plies. The effect of triangular, rectangular, square and circular cut-out defect has been investigated and compared to a virgin material that has no flaw or cut-out defect in the plies. It has been observed and hence reported that the circle induced flaw has caused 73% reduction in the impact strength due its 360° distortion of carrying stress. The failure mode of the circular cut-out defect specimens was proven to be matrix crack due to miscarriage of the stresses in the fibre, while a pull-out fibres failure mode has been observed in the virgin specimen. The experimental work has been validated using FEA analysis that identically simulate the boundary condition of both bending and impact test.Published versio

SARS-CoV-2, influenza virus and nanoscale particles trapping, tracking and tackling using nanoaperture optical tweezers: A recent advances review

This is the published version of an article published by iScienceIn Publishing in Journal of Materials NanoScience on 02/12/2020, available online: http://pubs.iscience.in/journal/index.php/jmns/article/view/1174Recent advances in nanoscale technologies have provided advanced tools that can be easily used to trap, track, and manipulate individual nanoscale particles and viruses such as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and influenza viruses accurately. Among the promising strategies that exist to date, optical forces based techniques are the leading tools in this task. Perfectly, focused lasers act as “optical tweezers,” and can trap individual particles and viruses. These forces can be applied to study nanomaterials, viruses, the building blocks of a quantum computer, and collision processes occurring between molecules in a better way than ever before. These cutting-edge tools are capable of trapping, tracking, and manipulating at the nanoscale in three dimensions. The optical tweezers have been used within biological and nanotechnological fields for trapping, tracking, and manipulating nanoparticles, and viruses with high flexibility, precision, and integration. The outcomes are important breakthroughs in the field of molecular mechanics. Here, we review the state-of-the-art optical tools employed in optical trapping, tracking, and manipulation of different particles at the nanoscale. The trapping of nanoparticles down to single-digit nanometer range and individual SARS-CoV-2 are the main features discussed here. Optical tweezers are also capable of sizing and probing acoustic modes of a small virus such as SARS-CoV-2 and influenza. The optical tweezers can perform tracking of nanoparticles in three-dimensional with high-resolution by forwarding scattered light. Optical tweezers are used to grab single molecules and measure events that are occurring and employed for measuring forces and measuring distance. A miniature and modular system creates a reliable and mobile optical trap that has more potential to be applied in optical trapping technologies

Cleaning the molecular machinery of cells via proteostasis, proteolysis and endocytosis selectively, effectively, and precisely: intracellular self-defense and cellular perturbations

This is an accepted manuscript of an article published by Royal Society of Chemistry in Molecular Omics on 02/11/2020, available online: https://doi.org/10.1039/D0MO00085J The accepted version of the publication may differ from the final published version.Network coordinates of cellular processes (proteostasis, proteolysis, and endocytosis), and molecular chaperones are the key complements in the cell machinery and processes. Specifically, cellular pathways are responsible for the conformational maintenance, cellular concentration, interactions, protein synthesis, disposal of misfolded proteins, localization, folding, and degradation. The failure of cellular processes and pathways disturbs structural proteins and the nucleation of amyloids. These mishaps further initiate amyloid polymorphism, transmissibility, co-aggregation of pathogenic proteins in tissues and cells, prion strains, and mechanisms and pathways for toxicity. Consequently, these conditions favor and lead to the formation of elongated amyloid fibrils consisting of many-stranded β-sheets (N,N-terminus and C,C-terminus), and abnormal fibrous, extracellular, proteinaceous deposits. Finally, these β-sheets deposit, and cells fail to degrade them effectively. The essential torsion angles (φ, ψ, and ω) define the conformation of proteins and their architecture. Cells initiate several transformations and pathways during the regulation of protein homeostasis based on the requirements for the functioning of the cell, which are governed by ATP-dependent proteases. In this process, the kinetics of the molding/folding phenomenon is disturbed, and subsequently, it is dominated by cross-domain misfolding intermediates; however, simultaneously, it is opposed by small stretching forces, which naturally exist in the cell. The ubiquitin/proteasome system deals with damaged proteins, which are not refolded by the chaperone-type machinery. Ubiquitin-protein ligases (E3-Ub) participate in all the cellular activity initiated and governed by molecular chaperones to stabilize the cellular proteome and participate in the degradation phenomenon implemented for damaged proteins. Optical tweezers, a single-resolution based technique, disclose the folding pathway of linear chain proteins, which is how they convert themselves into a three-dimensional architecture. Further, DNA-protein conjugation analysis is performed to obtain folding energies as single-molecule kinetic and thermodynamic data.Published versio

Review insights of nanotheranostics for molecular mechanisms underlying psychiatric disorders and commensurate nanotherapeutics for neuropsychiatry: the mind-knockout

© 2021 The Authors. Published by Ivyspring International Publisher. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://dx.doi.org/10.7150%2Fntno.49619Bio-neuronal led psychiatric abnormalities transpired by the loss of neuronal structure and function (neurodegeneration), pro-inflammatory cytokines, microglial dysfunction, altered neurotransmission, toxicants, serotonin deficiency, kynurenine pathway, and excessively produced neurotoxic substances. These uncontrolled happenings in the etiology of psychiatric disorders initiate further changes in neurotransmitter metabolism, pathologic microglial, cell activation, and impaired neuroplasticity. Inflammatory cytokines, the outcome of dysfunctional mitochondria, dysregulation of the immune system, and under stress functions of the brain are leading biochemical factors for depression and anxiety. Nanoscale drug delivery platforms, inexpensive diagnostics using nanomaterials, nano-scale imaging technologies, and ligandconjugated nanocrystals used for elucidating the molecular mechanisms and foremost cellular communications liable for such disorders are highly capable features to study for efficient diagnosis and therapy of the mental illness. These theranostic tools made up of multifunctional nanomaterials have the potential for effective and accurate diagnosis, imaging of psychiatric disorders, and are at the forefront of leading technologies in nanotheranostics openings field as they can collectively and efficiently target the stimulated territories of the cerebellum (cells and tissues) through molecular-scale interactions with higher bioavailability, and bio-accessibility. Specifically, the nanoplatforms based neurological changes are playing a significant role in the diagnosis of psychiatric disorders and portraying the routes of functional restoration of mental disorders by newer imaging tools at nano-level in all directions. Because of these nanotherapeutic platforms, the molecules of nanomedicine can penetrate the Blood-Brain Barrier with an increased half-life of drug molecules. The discoveries in nanotheranostics and nanotherapeutics inbuilt unique multi-functionalities are providing the best multiplicities of novel nanotherapeutic potentialities with no toxicity concerns at the level of nano rangeThe authors thank the National Institute of Medical Sciences, India, for financial support

Biomolecular interaction simulation of supramolecular topologies of organometallic assemblies of Bi(V) with antibiotic Tetracycline Amoxicillin drugs and their experimental activities evaluation

This is an accepted manuscript of an article published by IS Publications in Journal of Biomedical & Therapeutic Sciences on 30/09/2020, available online: http://www.pubs.iscience.in/journal/index.php/jbts/article/view/926/594 The accepted version of the publication may differ from the final published version.Antibiotic drugs i.e. tetracycline and amoxicillin, were used mixed ligands (ML), for designing, architecturing, tailoring and synthesis for synthesis of supramolecular topologies of organometallic assemblies of Bi(V), represented as OMCs‐Bi(V), having O5 set for bonding. Molecular models were proposed as a standard to judge specific interactions in topologies of molecules of ML and derived organometallic assemblies. In OMCs‐Bi(V), on chelation, polarity of Bi(V) get reduced to great extent due to overlap of ML orbital. As a result, delocalization of π‐electrons density clouds get spread over the surface of chelating ring and enhances penetration power of OMCs‐Bi(V) into lipid membranes. This influenced binding with enzyme sites in microorganisms. Some electron set for bonding groups present in ligands moieties display extensive biological activity that may be responsible for increase in hydrophobic character and liposolubility of supramolecular topologies of organometallic of assemblies; ultimately enhanced biological activity of OMCs‐Bi(V)

Laser Cleaning of Grey Cast Iron Automotive Brake Disc: Rust Removal and Improvement in Surface Integrity

There is a great need for removal of rust and surface damage from corroded engineering parts. This enables the retention of strength and increased longevity of metals and alloys in general. The use of lasers for cleaning, polishing and ablation has proven to be effective and promising overtime. This research is focused on a parametric study of laser cleaning a corroded grey cast iron brake disc. A continuous wave CO2 laser having a wavelength of 10.6μm was used for the study. A systematic approach was employed for the experiments where one parameter was changed while other parameters remained constant. Additional effects of laser cleaning were predicted by a Gaussian process regression approach. The results revealed that the best parameters which cleanly removed the rust were 60W of laser power, 900mm/s traverse speed, and a spot size of 722μm. The enhancement of surface microhardness of laser cleaned specimen was 37% compared to the rusted specimen surfaces. The roughness of the laser cleaned surface was, 1.29μm while the rusted surface comprised of 55.45μm (Ra). Microstructural analysis showed a presence of randomly distributed graphite flakes surrounded by a pearlitic matrix containing ferrite and cementite after laser cleaning. This was similar to that of the un-rusted surface. The hardness, roughness and microstructural content were in close relation with the respective properties of the unrusted automotive brake disc. This showed that the mechanical and physical properties of the brake disc were not altered negatively during the laser cleaning process. Implementation of the laser-cleaning technique in automotive and manufacturing industries should be embraced as it provides a faster, safer and cheaper way of enhancing the surface integrity of components and also paves way for other surface enhancement methodologies to be applied such as blast cleaning or laser shock cleaning for inducing extra strength, by beneficial residual stresses

Chronic pain evaluation in breast cancer patients using the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS): a single center cross-sectional retrospective study

Background: Breast cancer is the most common cancer in India, and the number of survivors has increased over the last few years. Pain is one of the most common symptoms during cancer treatment due to either the disease itself or adverse effects of treatment. The available data suggests that breast cancer patients have a high prevalence of neuropathic pain. Patients and methods: A cross sectional observational study was done at the Department of Radiation Oncology, between November 2021 to June 2022. The patients were admitted and screened for participation, non-metastatic post operative breast cancer on regular follow up for 2 years after their last chemotherapy or radiotherapy and not having any chronic neuropathy disease and the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale was used to assess the neuropathy pain status of patients. Patients’ demographics, clinical characteristics, and treatment of surgery, radiation therapy, and chemotherapy were collected and the comparison of the pain score between the patients was analysed. Results: Total of 149 patients were included in the study. S-LANSS score was calculated in the study population and more than 61% of participants reported a score equal or greater than 12, suggesting a predominant neuropathic pain component. Autonomic dysfunction, thermal pain, and allodynia were more prevalent in patients who underwent mastectomies compared to breast-conserving surgery. Whereas the dysesthesia and autonomic dysfunction score was higher in only the anthracycline group. Conclusions: The most important index for quality of life in cancer patients is the presence of persistent chronic pain and it is important to classify it accordingly in order to provide the best management. Using the S-LANSS score, the pattern of neuropathic pain can be determined early which leads to early intervention