162 research outputs found
Sol-Gel Synthesis and in Vitro Characterization of Bioactive Glass Ceramics using Rice Husk Ash Waste Material
Glass-ceramics materials share many properties with both glass and more traditional crystalline ceramics. It is formed as a glass, and then made to crystallize partly by heat treatment. . Bioactive glass-ceramics describes the beneficial or adverse effects of glass-ceramic with living tissue , when placed in body.
Bioactive glasses and glass-ceramics are more and more studied because of their surface chemical reactivity when in contact with body fluids [1–3]; by a complex mechanism of ions leaching and partial dissolution of the glass surface, the precipitation of bone-like apatite from the solution provides a strong chemical bonding with tissues. Since bioactive glasses and glass-ceramic are brittle materials, they are especially used in the field of small bone defects reconstruction, or as coatings on inert substrates for load-bearing prostheses.
Since the discovery of bioglass by Hench et al. [4] in the early 1970s, various types of ceramic, glass and glass–ceramic have been proposed and used as bone replacement biomaterials [5-7]. Specifically, these biomaterials have found clinical applications as coating for prostheses, bone filler, vertebral substitution and, in a porous form, as bone substitutes [8-15]. Most of them are based on the SiO2–P2O5–CaO–Na2O system. Bonding between bioactive glass or glass–ceramic and the surrounding tissues takes place through the formation of a hydroxyapatite layer, which is very similar to the mineral phase of bone. When the bioactive glass is placed in contact with physiological fluids, this layer is formed through a complex ion-exchange mechanism with the surrounding fluids, known as bioactivity.
This biologically-active layer of hydroxyapatite can form on the surface of glasses having a wide compositional range, and is considered as self by the surrounding living tissue; its presence is widely recognized to be a sufficient requirement for the implant to chemically bond with the living bone. Kokubo et al. [16] proposed the Tris-buffered simulated body fluid (SBF) for the in vitro study of bioactive glass and glass–ceramic, since its ion concentration is almost equal to that of human blood plasma. Since then, in vitro tests in SBF have been widely used as preliminary tests on new candidate materials showing bioactive properties. The ion leaching phenomenon involves the exchange of monovalent cations from the glass, such as Na+ or K+, with H3O+ from the solution, and thus causes an increase in the pH of the solution. It is known that osteoblasts prefer a slightly alkaline medium [17, 18], but it is also known that severe changes in pH can inhibit osteoblast activity and cause cell necrosis or apoptosis [19-21].
Different bioactive glass and glass ceramics have been synthesized in order to get desired mechanical, chemical properties by obtaining required microstructure. Some of common components used are Na2O, CaO, P2O5, SiO2 for synthesis of 45S5 and S53P4. In addition to these above components, varying composition of K2O, MgO , B2O3 are used to get 13-93, 3-04, 18-04, 23-04. There are some other glass and glass ceramics which also include ZnO, Ag and Al2O3.
In current study of bioactive glass ceramic we are using rice husk ash as raw material for synthesis of silica, which is amorphous in nature. It is cheap, easily available source with high content of silic
Characterization of amylase and protease activity in the digestive tract of two teleosts (Labeo rohita and Anabas testudineus) with different feeding habits
Two teleosts (Rohu, Labeo rohita and Koi, Anabas testudineus), both with contrasting feeding habits (herbivorous versus carnivorous) were studied for amylase and protease activity concerning diff erent regions of their digestive tracts. Signifi cant diff erences in enzymatic activity across diff erent regions of the digestive tracts were observed. Rohu, with three equal regions of the stomachless gut, showed the highest amylolytic activity at the posterior digestive tract but the highest proteolytic activity is limited to mid region. Contrary to such observation, Koi with three distinct regions of the digestive tract (stomach, pyloric caeca and intestine), the pyloric caeca exhibited the highest specifi c activity for both amylase and total protease. The optimum pH and temperature conditions were determined concerning the activity for both amylase and protease
Wireless Controlled Robotic Automation System
The project is to develope a controller and to control a 6 DOF robotic arm for Pick & Place Application over wireless. The objective is to learn various types of control methods for the pick and place robotic arm for educational purpose uses. The 6-DOF robot arm is controlled by a serial servo controller circuit board. The controller board utilizes a Atmega328 microcontroller ( Boot loaded with Arduino Diecimila Bootloader ) from Atmel Corporation as the control system to control all the activities. The input sensors like potentiometers will send a the input signals to the microcontroller, then microcontroller will analyze the data accordingly and will send control signals to the output devices. This output signal basically turns ON or OFF the output devices such as servo motors. The servo controller board is connected to the serial port on a PC running the Microsoft Windows operating system. The ATMega328 will be programmed to run robot arm sequences independently by help of a FT232RL breakout board. Arduino integrated development environment (IDE) is used to develop the arduino sketch.
Various types of control methods have been implemented. Manual control of the Robotic arm by mirroring the designed prototype movements. Prototype was developed by help of sensors like potentiometers. Also automated control of the robotic arm has been realized. The controller is also interfaced with a XBee XBP24-AWI-001 wireless module for remote control of the robotic arm from a PC using a graphical user interface (GUI), which was designed using processing development environment (PDE).The EEPROM present in Atmega328 MC unit has been utilized to make the robotic arm learnable. i.e. it can learn the movements stored in the memory and can replay it whenever prompted remotely. Programming is done remotely and the output data is sent over wireless to control the robotic arm
A study on ultrasound based transdermal drug delivery system
The development of an ultrasound based Transdermal drug delivery device (or sonophoresis) has received increased attention over the past few years. Meaningful enhanced carrying of model drugs such as mannitol and insulin has been determined using commercial sonicators. However, its practical use is hampered by its large size and weight of the common ultrasound transducer devices. In this project work, a remote controlled drug delivery system (sonophoresis device) with a flat flextensional ultrasound transducer was proposed. It is clearly known that low frequency ultrasound can be used to enhance transdermal drug penetration which is known as sonophoresis. Scientifically, acoustic cavitations outcome in the creation of defects in the stratum corneum allows accelerated absorption of currently applied molecules. The aim of this study was to develop a low cast optimized remotely controlled sonophoresis device with variable resonant frequency for studying Transdermal drug delivery in vitro. Following acoustic validation, 21.75 kHz ultrasound was applied for different durations (range: 5 s to1 min) using three different modes (10%, 33% or 100% duty cycles). The simulation result of first resonance frequency was found to be comparable to that of the experimental result. In comparison with the other types of sonophoresis device, it has a simple structure and its fabrication process is easy and inexpensive
Femoral head diameters in Nepalese patients undergoing hemiarthroplasty
Background: Sizing of the femoral head is important for determining the appropriate size of implants to be used for a patient undergoing hip arthroplasty. The present study aimed to determine the mean diameter of femoral head in Nepalese population who underwent hemiarthroplasty in our department.Methods: We retrospectively reviewed the medical records of patients who underwent hemiarthroplasty from December 2016 till December 2020. We included patients aged more than 50 years who underwent hemiarthroplasty. The diameter of the femoral head was measured intraoperatively using standard fully circular templates. For radiological measurements, X-ray of pelvis with hips anteroposterior view were included.Results: A total of 600 femoral heads were evaluated, 400 of women and 200 of men. Of these cases, the femoral head diameter were evaluated based on x-ray pelvis in 500 cases and rest of the 100 cases were evaluated intraoperatively. The mean age of the patients in our sample was 75.2±9.4 (range 50–90) years. Overall, the mean femoral head diameter (with intact articular cartilage) was 44.9±3.2 (range 39–53 mm) mm. Among the male patients, mean femoral head diameter was 47.7±2.8 mm, which was found to be significantly higher than that of female patients, who had a mean femoral head diameter of 43.7±2.4 mm, p value <0.05.Conclusions: Further studies are needed in other geographical locations, so that reference values could be established for specific regions
Pediatric long bone fractures treated by elastic intramedullary nailing
Background: Pediatric long bone fractures can have a high morbidity and long term disability among the survivors. The present study was aimed to study the clinical outcomes of children with long bone fractures managed by elastic intramedullary nail.Methods: We retrospectively reviewed the medical records of children (aged 2 to 15 years) who were admitted and treated for unilateral femoral, tibial or forearm fractures with elastic intramedullary nail from January 2018 till February 2020. All were managed with elastic intramedullary nailing. The union times and complications were noted from the medical records.Results: Femoral, tibial and forearm bones were involved in 15 patients each (33.3%). Road traffic accident was reported by 31%) and physical abuse by one case (2%). The mean time of union was 10 weeks, ranging from 6 to 12 weeks. The mean time for union of the femur and tibia was 11.54 and 11.34 weeks respectively. It was significantly lower for forearm (6.67 weeks, p value <0.05). Two patients reported of bursitis and impingement, which were resolved after nail removal. One case had limb length discrepancy of about 0.5 cm in femur fracture, which was not impairing functional activity. Functional status was assessed based on Flynn criteria was found to be excellent in 36%, good in 44% and fair in 20%.Conclusions: The results of the present study show that titanium elastic nail (TEN) is an effective treatment modality for managing pediatric long bone fractures. We recommend the use of TEN in managing long bone fractures in children
Regeneration and Preliminary Characterization of Asian and African Okra (Abelmoschus spp.) Germplasm
The morphological variability of 56 okra (Abelmoschus spp.) Accessions was evaluated over two years (2008 and 2009). Ten (10) agromorphological characters were evaluated in the Sadoré station in Niger. The hierarchical ascendant classification (CAH) and the discriminant factor analysis (AFD) revealed four groups (GI, GII, GIII and GIV). The accessions in groups I and IV have high values of Lfm, Dfm, Height, and Nloc, Nepi and cons by low values. However, Flo or Fruct values are relatively higher in accessions of group III and IV than in accessions of group I. Similarly, accessions of group II have higher values in Flo and Fruct than group II. However, accessions of group II are much later in terms of which accessions in group I, which, in turn, have lower values in Flo and Fruct, so these are compared to those of Group II. The results show that the most discriminating variables that make it possible to describe Variability among the groups identified are the diameter of mature fruits (Dfm), Plant height (Height) and branch of plant number (Nbrch). The characters analyzed can thus constitute basic criteria to differentiate accessions from other regions of West Africa and serve for a study of variability between the remains of okra accessions collected in Niger. Opportunities for improvement can also be considered to identify varieties that have a high adaptive potential due to climate change
Invasive Alien Flora in and around an Urban Area of India
Invasive alien species are non-native exotic organisms which can disperse and destroy the biodiversity and change the ecosystem. The present study deals with the comprehensive list of invasive alien plants (IAPs) of Rourkela Steel City, Sundargarh, Odisha, with background information on family, habit, and nativity. A total of 165 invasive alien species under 132 genera and 59 families have been recorded. From the nativity study, among 25 geographic regions, the majority of invasive plants reported from American continent (62%) with 103 species. While in life form analysis, the herbs (114 species) are dominant, followed by trees (23 species), shrubs (22 species), climber (5 species), and undershrub (1 species). Ageratum conyzoides, Blumea lacera, Cassia alata, Lantana camara, Cassia tora, Parthenium hysterophorus, Xanthium sp., Datura sp., Cardamine scutata, Argemone mexicana, Grangea maderaspatana, Hyptis suaveolens, and Gnaphalium polycaulon are some noxious species found during the study. Parthenium hysterophorus is the highly noxious plant which is grown everywhere after Ageratum conyzoides and Lantana camara. Most of the invasive species are locally used for medicinal purposes as well as for food, fuel, and fodder purposes. A better planning and reporting of the spread of new plants in the area are needed for early identification and control of the invasive alien plant species in different seasons. Since the flora of Sundargarh districts has not been beneficially explored, this study will help in the compilation of flora of Sundargarh district and Rourkela in particular. Further studies will reveal the allelopathic effects on different agricultural crops as well as the different ethnobotanical values
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