bio compatibility
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2021 ◽  
Vol 11 (12) ◽  
pp. 3038-3043
Author(s):  
S. M. Asha Banu ◽  
K. Meena Alias Jeyanthi

The most prevalent cancer that threatens women’s life is Breast cancer. According to WHO Statistics in 2020, 2.3 Million Women were diagnosed with Breast cancer and 685000 death rate were disclosed globally. In this paper, Wearable Health Diagnosis System (WHDS) based antenna for the identification of the early breast cancer is discussed. Conventional methods are limited by their uncomfortable testing setups, panic environment and failure in results. Recently, textile based antenna for microwave imaging stared to work on the detection of the cancer cells at the earlier stage in breast. WHDS antenna has the requirements of wider bandwidth, high resolution, low Specific Absorption Rate (SAR), bio compatibility, and flexibility. The proposed work is based on the textile antenna using Denim substrate (permittivity = 1.67, thickness = 2 mm) to diagnosis the Early Breast Cancer Tissues (EBCT). Using the following antenna parameters (return loss, E-filed, H-field and SAR values), the position and malignancy of the EBCT is identified. Since the dielectric properties of the cancer cells are high, the influence of the effective permittivity is higher on the E-field and SAR. Along with the above parameters, comparison of various substrate materials (Denim, FR4, and RT duroid) were also tested and Denim is selected for our application as it introduces greater reflection co-efficient and wider bandwidth. The proposed antenna is designed to operate at a frequency of 2–4 GHz. This miniaturised antenna has a volume of 30 × 28 × 2 mm3.


2021 ◽  
Vol 21 (6) ◽  
pp. 424
Author(s):  
M. A. Otache ◽  
R. U. Duru ◽  
O. Achugasim ◽  
O. J. Abayeh

Nowadays, Sugar esters (SEs) have become the focus of researchers due to their biocompatibility and extensive industrial applications as surfactants. This trend provides new methods and opportunities for the development of green synthetic chemistry. Taking the above into consideration, a critical review presented in this work emphasized the efficiency of catalyzing the synthesis of SEs with minimal hazardous by-products. These catalytic media have been employed with various impacts involving chemical, biological, and other catalytic materials. Chemical methods have been reported to show limitations in terms of preparation and bio-compatibility. To solve these shortcomings, therefore, other technologies have been adopted; ionic liquids (eutectic solvents), chemo-enzymatic systems and chemo-enzymatic systems on a catalytic surface. The use of chemo-enzymatic systems on catalytic surfaces has proved to be suitable in solving biocompatibility and stability problems and correspondingly increasing the yield of esters formed. Therefore, finding an improved catalytic surface, and the sustainable optimal reaction conditions for enzymes will be vital to improving sugar ester conversion. This study highlights the different catalytic advances employed in the esterification of SEs.


Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1071
Author(s):  
Weiqiang Wang ◽  
Rui Zhang

Lyotropic chromonic liquid crystals (LCLCs) are a special type of hierarchical material in which self-assembled molecular aggregates are responsible for the formation of liquid crystal phases. Thanks to its unusual material properties and bio compatibility, it has found wide applications including the formation of active nematic liquid crystals. Recent experiments have uncovered tumbling character of certain LCLCs. However, how tumbling behavior modifies structure and flow in driven and active nematics is poorly understood. Here, we rely on continuum simulation to study the interplay of extensile active stress and externally driven flow in a flow-tumbling nematic with a low twist modulus to mimic nematic LCLCs. We find that a spontaneous transverse flow can be developed in a flow-tumbling active nematic confined to a hybrid alignment cell when it is in log-rolling mode at sufficiently high activities. The orientation of the total spontaneous flow is tunable by tuning the active stress. We further show that activity can suppress pressure-driven flow of a flow-tumbling nematic in a planar-anchoring cell but can also promote a transition of the director field under a pressure gradient in a homeotropic-anchoring cell. Remarkably, we demonstrate that the frequency of unsteady director dynamics in a tumbling nematic under Couette flow is invariant against active stress when below a threshold activity but exhibits a discontinuous increase when above the threshold at which a complex, periodic spatiotemporal director pattern emerges. Taken together, our simulations reveal qualitative differences between flow-tumbling and flow-aligning active nematics and suggest potential applications of tumbling nematics in microfluidics.


Author(s):  
Mukesh Tak ◽  
Rakesh Mote

Abstract Titanium and its alloys are considered as difficult to cut material classes, and their processing through the traditional machining methods is a painful task. These materials have an outstanding combination of properties like high specific strength, excellent corrosive resistance, and exceptional bio-compatibility; therefore, they have broad fields of application like aerospace, MEMS, bio-medical, etc. Electrochemical micromachining (ECMM) is a very vital process for the production of micro-domain features in difficult-to-machine materials. The machining issue with ECMM for titanium and their alloys is the passive layer formation, which hinders the dissolution and causes stray removal. To overcome these issues, a hybrid ECMM approach has been proposed by using a diamond abrasive tool combined with ECMM. The present study focuses on the detailed characterization of the passive layer formed using the hybrid approach. Through the use abrasive tool, the abrasive grits scoop the passive layer by the mechanical grinding action, formed in micro-drilling on the Ti6Al4V alloy to expose a new surface for further dissolution. The micro-holes were produced incorporating the abrasive tool and then compared by the holes created using a cylindrical tool (tool without abrasive). The taper and the stray dissolution of the micro-holes were also compared, produced at different applied potentials. The minimum average entry overcut and exit overcut of the hole were obtained as 29 µm and 3 µm, respectively, also a micro-hole with the lowest taper of 2.7°, achieved by the use of the abrasive micro tool.


2021 ◽  
Author(s):  
Richard Ellingham ◽  
Tim Giffney

Abstract The high stretchability, scalability and bio-compatibility of carbon black nanoparticle (CB)-polydimethylsiloxane (PDMS) elastomer composites are attractive characteristics for diverse applications ranging from the biomedical to aerospace fields. These materials are particularly useful as high strain sensors, but show stress relaxation and resistance relaxation behaviour that must be better understood in order to improve sensing performance and optimize the material design. In this work, we have characterized and modelled the resistance relaxation behaviour of these composites to understand the response of resistance to transient step strain input. CB-PDMS specimens have been fabricated with 7.5 and 10 weight percentage (w.t.%) of CB and subjected to repeated stretching while continually monitoring resistance and stress. A model for the resistive relaxation in time has been developed using 30 relaxations to give maximum coefficients of variance of the constants of 18.54% and 52.72% for 7.5 and 10 w.t.% of CB. The ability to model resistance relaxation is useful for the development of, accurate, highly flexible dynamic strain sensors.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hidehisa Satta ◽  
Tamio Iwamoto ◽  
Yuki Kawai ◽  
Naoaki Koguchi ◽  
Kazuhiko Shibata ◽  
...  

Abstract Background A novel hemodialysis (HD) system employing electrolyzed water containing molecular hydrogen (E-HD) has been developed to improve the bio-compatibility of HD. This study examined the impact of E-HD on changes in redox state during HD and HD-related fatigue. Method This single-arm, prospective observational study examined 63 patients on chronic HD (41 males; mean age, 72 ± 9 years; median duration of HD, 7 years). Redox parameters (serum myeloperoxidase [MPO], malondialdehyde-protein adduct [MDA-a], thioredoxin 1 [TRX]) during HD were compared between control HD (C-HD) and E-HD after 8 weeks. Fatigue was evaluated using a numerical rating scale (NRS) during the 8-week course. Results In C-HD, an increase in serum MPO accompanied increases in both oxidative products (MDA-a) and anti-oxidant molecules (TRX). In E-HD, although increases in MPO were accentuated during HD, changes in MDA-a and TRX were ameliorated as compared with C-HD. In patients who showed HD-related fatigue (47%) during C-HD, change in MDA-a by HD was a risk factor for the presence of fatigue. During the 8 weeks of observation on E-HD, those patients displayed significant decreases in fatigue scores. Conclusion E-HD ameliorates oxidative stress and supports anti-oxidation during HD, suggesting improved bio-compatibility of the HD system. E-HD may benefit patients with HD-related fatigue, but the mechanisms underlying changes to oxidative stress have yet to be clarified.


2021 ◽  
Vol 23 (06) ◽  
pp. 1618-1634
Author(s):  
Bharathi S ◽  
◽  
Dr.Mekala M ◽  
Sanjay Prasad S ◽  
◽  
...  

Acne by definition is a multifactorial continual inflammatory ailment of pilosebaceous units. Although antibiotics play an essential role in acne control, the development of drug resistance among acne-causing bacteria (Propionibacterium acne and Streptococcus sp)had created a need for the development of novel antimicrobial agents. Therefore, the present study focuses on the development of anti-acne cream using extracts of Oscillatoria sp. Oscillatoria extracts were used as a major constituent for acne cream with paraffin wax as the cream base. The Oscillatoria extracts and developed cream were investigated for antibacterial activity against acne-causing bacteria. The biocompatibility of the acne cream was evaluated by a patch test and Brine shrimp lethality assay was performed to determine the toxicity of the developed cream. The extract and acne-cream showed 14mm and 15mm; and 13mm and 11mm against Propioni bacterium acnes and Streptococcus sp. The cream showed no irritation endpoints and it was found to be non-toxic. Thus the developed anti-acne cream can be developed as a product for the treatment of acne.


Author(s):  
Md Ahasan Habib ◽  
Bashir Khoda

Abstract 3D bio-printing is an emerging technology to fabricate tissue scaffold in-vitro through the controlled allocation of biomaterial and cell, which can mimic the in-vivo counterpart of living tissue. Live cells are often encapsulated into the biomaterials (i.e., bio-ink) and extruded by controlling the printing parameters. The functionality of the bioink depends upon three factors: (a) printability, (b) shape fidelity, and (c) bio-compatibility. Increasing viscosity will improve the printability and the shape fidelity; but will require higher applied extrusion pressure, which is detrimental to the living cell dwelling in the bio-ink, which is often ignored in bio-ink optimization process. In this paper, we demonstrate a roadmap to develop and characterize bio-inks ensuring the printability, shape fidelity, and cell survivability, simultaneously. The pressure exerted on the bio-ink during extrusion processes is measured analytically and the information is incorporated in the rheology design of the bio-ink. Cell-laden filament is fabricated with Human Embryonic Kidney (HEK 293) cell and analyzed the cell viability. The overall cell viability of the filament fabricated with 8 psi and 12 psi is 90% and 74% respectively. Additionally, a crossectional live-dead assay of the printed filament with HEK 293 cell is performed which demonstrates the spatial pattern that matches our findings as well.


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