| 1. |
- Ans, Muhammad, et al.
(författare)
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Designing of non-fullerene 3D star-shaped acceptors for organic solar cells
- 2019
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Ingår i: Journal of Molecular Modeling. - : Springer. - 1610-2940 .- 0948-5023. ; 25:5
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Tidskriftsartikel (refereegranskat)abstract
- The design and fabrication of solar cells have recently witnessed the exploration of non-fullerene-based acceptor molecules for higher efficiency. In this study, the optical and electronic properties of four new three-dimensional (3D) star-shaped acceptor molecules (M1, M2, M3, and M4) are evaluated for use as acceptor molecules in organic solar cells. These molecules contain a triphenylamine donor core with diketopyrrolopyrrole acceptor arms linked via a thiophene bridge unit. Molecules M1–M4 are characterized by different end-capped acceptor moieties, including 2-(5-methylene-6-oxo-5,6-dihydrocyclopenta-b-thiophen-4-ylidene)malononitrile (M1), 2-(2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (M2), 2-(5-methyl-2-methylene-3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (M3), and 3-methyl-5-methylnene-thioxothiazolidin-4-one (M4). The properties of the newly designed molecules were compared with a well-known reference compound R, which was recently reported as an excellent acceptor molecule for organic solar cells. Molecules M1–M4 exhibit suitable frontier molecular orbital patterns for charge mobility. M2 shows maximum absorption (λmax) at 846.8 nm in dichloromethane solvent, which is ideal for the design of transparent solar cells. A strong electron withdrawing end-capped acceptor causes a red shift in absorption spectra. All molecules are excellent for hole mobility due to a lower value of λh compared to the reference R.
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| 2. |
- Brownstein, Catherine A., et al.
(författare)
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An international effort towards developing standards for best practices in analysis, interpretation and reporting of clinical genome sequencing results in the CLARITY Challenge
- 2014
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Ingår i: Genome Biology. - : Springer Science and Business Media LLC. - 1465-6906 .- 1474-760X. ; 15:3, s. R53-
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Tidskriftsartikel (refereegranskat)abstract
- Background: There is tremendous potential for genome sequencing to improve clinical diagnosis and care once it becomes routinely accessible, but this will require formalizing research methods into clinical best practices in the areas of sequence data generation, analysis, interpretation and reporting. The CLARITY Challenge was designed to spur convergence in methods for diagnosing genetic disease starting from clinical case history and genome sequencing data. DNA samples were obtained from three families with heritable genetic disorders and genomic sequence data were donated by sequencing platform vendors. The challenge was to analyze and interpret these data with the goals of identifying disease-causing variants and reporting the findings in a clinically useful format. Participating contestant groups were solicited broadly, and an independent panel of judges evaluated their performance. Results: A total of 30 international groups were engaged. The entries reveal a general convergence of practices on most elements of the analysis and interpretation process. However, even given this commonality of approach, only two groups identified the consensus candidate variants in all disease cases, demonstrating a need for consistent fine-tuning of the generally accepted methods. There was greater diversity of the final clinical report content and in the patient consenting process, demonstrating that these areas require additional exploration and standardization. Conclusions: The CLARITY Challenge provides a comprehensive assessment of current practices for using genome sequencing to diagnose and report genetic diseases. There is remarkable convergence in bioinformatic techniques, but medical interpretation and reporting are areas that require further development by many groups.
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| 3. |
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| 4. |
- Idris, Alamin, et al.
(författare)
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Oxygen Barrier Performance of Poly (Vinyl Alcohol) Coating Films with Different Induced Crystallinity and Model Predictions
- 2021
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 11, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- The presence of the crystalline regions in poly(vinyl alcohol) coating films acts as barrier clusters forcing the gas molecules to diffuse in a longer pathway in the amorphous region of the polymer, where diffusivity and solubility are promoted in comparison. Evaluating the influence of crystalline regions on the oxygen barrier property of a semi-crystalline polymer is thus essential to prepare better coating films. Poly(vinyl alcohol) coating films with varying induced crystallinity were prepared on a polyethylene terephthalate (PET) substrate by drying at different annealing temperatures for 10 min. The coating films were first delaminated from the PET substrate and then characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and X-ray diffraction (XRD) techniques to determine and confirm the induced percentage of crystallinity. The barrier performance of the coating films, i.e., the oxygen transmission rate (OTR), was measured at room temperature. Results showed a decrease in the OTR values of poly(vinyl alcohol) film with an increase in the degree of crystallinity of the polymer matrix. Tortuosity-based models, i.e., modified Nielsen models, were adopted to predict the barrier property of the semi-crystalline PVOH film with uniform or randomly distributed crystallites. A modified Nielsen model for orderly distributed crystallites with an aspect ratio of 3.4 and for randomly distributed crystallites with an aspect ratio of 10.4 resulted in a good correlation with the experimental observation. For the randomly distributed crystallites, lower absolute average relative errors of 4.66, 4.45, and 5.79% were observed as compared to orderly distributed crystallites when the degree of crystallinity was obtained using FTIR, DSC, and XRD data, respectively.
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| 5. |
- Iftikhar, Bawar, et al.
(författare)
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Experimental study on the eco-friendly plastic-sand paver blocks by utilising plastic waste and basalt fibers
- 2023
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Ingår i: Heliyon. - : Elsevier. - 2405-8440. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- Plastic waste poses a significant hazard to the environment as a result of its high production rates, which endanger both the environment and its inhabitants. Similarly, another concern is the production of cement, which accounts for roughly 8% of global CO2 emissions. Thus, recycling plastic waste as a replacement for cementitious materials may be a more effective strategy for waste minimisation and cement elimination. Therefore, in this study, plastic waste (low-density polyethylene) is utilised in the production of plastic sand paver blocks without the use of cement. In addition to this, basalt fibers which is a green industrial material is also added in the production of eco-friendly plastic sand paver blocks to satisfy the standard of ASTM C902-15 of 20 N/mm2 for the light traffic. In order to make the paver blocks, the LDPE waste plastic was melted outside in the open air and then combined with sand. Variations were made to the ratio of LDPE to sand, the proportion of basalt fibers, and sand particle size. Paver blocks were evaluated for their compressive strength, water absorption, and at different temperatures. Including 0.5% percent basalt fiber of length 4 mm gives us the best result by enhancing compressive strength by 20.5% and decreasing water absorption by 50.5%. The best results were obtained with a ratio of 30:70 LDPE to sand, while the finest sand provides the greatest compressive strength. Moreover, the temperature effect was also studied from 0 to 60 °C, and the basalt fibers incorporated in plastic paver blocks showed only a 20% decrease in compressive strength at 60 °C. This research has produced eco-friendly paver blocks by removing cement and replacing it with plastic waste, which will benefit the environment, save money, reduce carbon dioxide emissions, and be suitable for low-traffic areas, all of which contribute to sustainable development.
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| 6. |
- Javed, Asif, 1982-, et al.
(författare)
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Crack analysis of barrier coatings based on starch and starch-PVOH with and without plasticizer
- 2018
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 33:2, s. 336-347
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Tidskriftsartikel (refereegranskat)abstract
- Barrier coatings based on starch and starch-PVOH plasticized with glycerol and without plasticizer were applied to two different paperboard substrates, a triple coated board and duplex board, in order to investigate the tendency for cracks to develop in the barrier coating layers during creasing and folding. Tensile properties of films based on the starch and starch-PVOH blend were determined to investigate the relationship between the flexibility of the films and the cracking in the barrier coating layers. Furthermore, the oxygen transmission rate through the barrier-coated paperboard was measured before and after creasing and folding. The oxygen transmission rate through the barrier-coated samples was over the measurable range i. e. OTR > 10000 cm 3 / m 2 day\text{OTR}>10000\hspace{0.1667em}{\text{cm}}^{3}/{\text{m}}^{2}\hspace{0.1667em}\text{day} after creasing and folding, which indicated failure in the barrier coating layers. Optical microscopy revealed small cracks in the barrier coating layers, probably related to an increase in flexibility of the barrier coating layers. It was observed in scanning electron micrographs that cracks in the barrier coating layers seemed to follow the fibers when the barrier coating was applied on the rear side of the duplex board. Scanning electron micrographs and surface profiler images revealed that cracks in the barrier coating layers might have originated from the mineral coating layer when the starch and starch/PVOH coating layers were applied on the mineral-coated side of the triple coated board. An increase in the thickness of the barrier coating layer did not seem to increase the resistance to failure.
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| 7. |
- Javed, Asif, 1982-
(författare)
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Effects of plasticizing and crosslinking on coatings based on blends of starch-PVOH and starch-lignin
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A barrier material is usually needed on a fiber-based food package to protect the packed food from gases and moisture and thus maintain its quality. Barrier materials presently used in food packaging applications are mostly petroleum-based polymers. Over the last few decades, efforts have been made to replace petroleum-based materials with bio-based materials. The present work has focused on the possibility of using a natural barrier material on a fiber-based food package and the effects of plasticizing and cross-linking on the mechanical and barrier properties, and the stability in water of coatings based on starch-poly(vinyl alcohol) (PVOH) and starch-lignin blends.The flexibility of the starch films was increased by adding PVOH further by adding a plasticizer. It was shown that citric acid can act as a compatibilizer and cross-linker for starch and PVOH, and the use of citric acid may slow down the diffusion of both oxygen and water vapor if a multilayer coating strategy is used. The addition of polyethylene glycol to the pre-coating recipe resulted in a lower oxygen transmission rate through polyethylene-extruded board than when citric acid was added to the pre-coating. The flexibility of the barrier coatings and the properties of the base substrate affect the cracking tendency of the barrier coatings during the creasing and folding of a barrier-coated board.The addition of lignin to the starch reduced the migration of starch from the starch-lignin films and the addition of ammonium zirconium carbonate as a cross-linker reduced the migration of both starch and lignin from the films. The addition of starch to the lignin solution increased the solubility of lignin at low pH, and the pilot-coated board showed a significant decrease in migration of lignin from the coatings containing ammonium zirconium carbonate when the pH of the coating solution was decreased.
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| 8. |
- Javed, Asif, 1982-
(författare)
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Effects of plasticizing and crosslinking on the mechanical and barrier properties of coatings based on blends of starch and poly(vinyl alcohol)
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In the last decades, intensive research has been carried out in order to replace oil-based polymers with bio-based polymers due to growing environmental concerns. So far, most of the barrier materials used in food packaging are petroleum-based materials. The purpose of the barrier is to protect the packaged food from oxygen, water vapour, water and fat. The mechanical and barrier properties of coatings based on starch-plasticizer and starch-poly(vinyl alcohol) (PVOH)-plasticizer blends have been studied in the work described in this thesis. The plasticizers used were glycerol, polyethylene glycol and citric acid. In a second step, polyethylene coatings were extruded onto paperboard pre-coated with a starch-PVOH-plasticizer blend. The addition of PVOH to the starch increased the flexibility of the film. Curing of the film led to a decrease in flexibility and an increase in tensile strength. The flexibility of the starch-PVOH films was increased more when glycerol or polyethylene glycol was added than citric acid. The storage modulus of the starch-PVOH films containing citric acid increased substantially at high temperature.It was seen that the addition of polyethylene glycol or citric acid to the starch-PVOH blend resulted in an enrichment of PVOH at the surface of the films. Tensile tests on the films indicated that citric acid acted as a compatibilizer and increased the compatibility of the starch and PVOH in the blend. The addition of citric acid to the coating recipe substantially decreased the water vapour transmission rate through the starch-PVOH coated paperboard, which indicated that citric acid acts as a cross-linker for starch and/or PVOH. The starch-PVOH coatings containing citric acid showed oxygen-barrier properties similar to those of pure PVOH or of a starch-PVOH blend without plasticizer when four coating layers were applied on a paperboard. The oxygen-barrier properties of coatings based on a starch-PVOH blend containing citric acid indicated a cross-linking and increase in compatibility of the starch-PVOH blends.Polyethylene extrusion coating on a pre-coated paperboard resulted in a clear reduction in the oxygen transmission rate for all the pre-coating formulations containing plasticizers. The addition of a plasticizer to the pre-coating reduced the adhesion of polyethylene to pre-coated board. Polyethylene extrusion coating gave a board with a lower oxygen transmission rate when the paperboard was pre-coated with a polyethylene-glycol-containing formulation than with a citric-acid-containing formulation. The addition of polyethylene glycol to pre-coatings indicated an increase in wetting of the pre-coated paperboard by the polyethylene melt, and this may have sealed the small defects in the pre-coating leading to low oxygen transmission rate. The increase in brittleness of starch-PVOH films containing citric acid at a high temperature seemed to have a dominating effect on the barrier properties developed by the extrusion coating process.
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| 9. |
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| 10. |
- Javed, Asif, 1982-, et al.
(författare)
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Lignin-containing coatings for packaging materials
- 2018
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Ingår i: Nordic Pulp & Paper Research Journal. - : Walter de Gruyter GmbH. - 0283-2631 .- 2000-0669. ; 33:3, s. 548-556
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical properties and chemical stability in water of self-supporting films made from aqueous solutions of starch and lignin, and the barrier properties of paperboard coated with solutions of these polymers have been studied. The dissolution of starch from the starch-lignin films in contact with the model liquids was decreased significantly when lignin was added to the starch films. The addition of ammonium zirconium carbonate (AZC) to the formulations as a crosslinking agent substantially increased the storage modulus of the starch-lignin films, which indicated that crosslinking had occurred. The addition of AZC to the formulations also led to a decrease in dissolution of both starch and lignin from the starch-lignin films in contact with model liquids. The effect of AZC on the water stability of the films was greater when the pH of the starch-lignin-AZC solution was adjusted with ammonia rather than NaOH. The addition of NH4Cl solution as a presumed catalyst to the recipe when the pH adjustment was performed with NaOH did not improve the effect of AZC on the water stability of the films. The water vapour transmission rate of the coated paperboard decreased slightly when AZC was added to the coating formulation.
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| 11. |
- Javed, Asif, 1982-, et al.
(författare)
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Lignin-containing coatings for packaging materials—pilot trials
- 2021
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Ingår i: Polymers. - : MDPI AG. - 2073-4360. ; 13:10
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Tidskriftsartikel (refereegranskat)abstract
- One severe weakness of most biopolymers, in terms of their use as packaging materials, is their relatively high solubility in water. The addition of kraft lignin to starch coating formulations has been shown to reduce the water solubility of starch in dry coatings. However, lignin may also migrate into aqueous solutions. For this paper, kraft lignin isolated using the LignoBoost process was used in order to examine the effect of pH level on the solubility of lignin with and without ammonium zirconium carbonate (AZC). Machine-glazed (MG) paper was coated in a pilot coating machine, with the moving substrate at high speed, and laboratory-coated samples were used as a reference when measuring defects (number of pinholes). Kraft lignin became soluble in water at lower pH levels when starch was added to the solution, due to the interactions between starch and lignin. This made it possible to lower the pH of the coating solutions, resulting in increased water stability of the dry samples; that is, the migration of lignin to the model liquids decreased when the pH of the coating solutions was reduced. No significant difference was observed in the water vapor transmission rate (WVTR) between high and low pH for the pilot-coated samples. The addition of AZC to the formulation reduced the migration of lignin from the coatings to the model liquids and led to an increase in the water contact angle, but also increased the number of pinholes in the pilot-coated samples. © 2021 by the authors
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| 12. |
- Javed, Asif, 1982-, et al.
(författare)
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Study of starch and starch-PVOH blends and effects of plasticizers on mechanical and barrier properties of coated paperboard
- 2016
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Ingår i: Nordic Pulp & Paper Research Journal. - : Swedish Association of Pulp and Paper Engineers. - 0283-2631 .- 2000-0669. ; 31:3, s. 499-510
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical properties of self-supporting films based on starch-plasticizer and starch-PVOH-plasticizer and the barrier properties of paperboard coated with solutions of these polymers have been studied. The plasticizers used were glycerol, polyethylene glycol and citric acid. It was shown that the addition of a plasticizer and PVOH to starch substantially increases the flexibility of starch films. It was seen that curing the self-supporting films led to a decrease in flexibility. After heat-treatment, a substantial increase in storage modulus was observed only in the starch-PVOH-citric-acid blend films. Tensile tests on the films indicate that citric acid did not cause any noticeable phase separation. Citric acid acted as a compatibilizer for starch-PVOH blends even though a similar enrichment of PVOH at the air-solid interface was observed with both citric acid and polyethylene glycol as plasticizer. The properties of barrier coatings greatly reflected the compatibility of starch-PVOH blends containing citric acid. The only plasticizer that resulted in a lower water vapour transmission rate through the starch and starch-PVOH coatings was citric acid, which suggests that cross-linking took place. With four layers, coatings based of starch-PVOH possessed the same oxygen- transmission rate with citric acid as without citric acid.
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| 13. |
- Javed, Muhammad Faisal, et al.
(författare)
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Evaluation of machine learning models for predicting TiO2 photocatalytic degradation of air contaminants
- 2024
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Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- The escalation of global urbanization and industrial expansion has resulted in an increase in the emission of harmful substances into the atmosphere. Evaluating the effectiveness of titanium dioxide (TiO2) in photocatalytic degradation through traditional methods is resource-intensive and complex due to the detailed photocatalyst structures and the wide range of contaminants. Therefore in this study, recent advancements in machine learning (ML) are used to offer data-driven approach using thirteen machine learning techniques namely XG Boost (XGB), decision tree (DT), lasso Regression (LR2), support vector regression (SVR), adaBoost (AB), voting Regressor (VR), CatBoost (CB), K-Nearest Neighbors (KNN), gradient boost (GB), random Forest (RF), artificial neural network (ANN), ridge regression (RR), linear regression (LR1) to address the problem of estimation of TiO2 photocatalytic degradation rate of air contaminants. The models are developed using literature data and different methodical tools are used to evaluate the developed ML models. XGB, DT and LR2 models have high R2 values of 0.93, 0.926 and 0.926 in training and 0.936, 0.924 and 0.924 in test phase. While ANN, RR and LR models have lowest R2 values of 0.70, 0.56 and 0.40 in training and 0.62, 0.63 and 0.31 in test phase respectively. XGB, DT and LR2 have low MAE and RMSE values of 0.450 min-1/cm2, 0.494 min-1/cm2 and 0.49 min-1/cm2 for RMSE and 0.263 min-1/cm2, 0.285 min-1/cm2 and 0.29 min-1/cm2 for MAE in test stage. XGB, DT, and LR2 have 93% percent errors within 20% error range in training phase. XGB has 92% and DT, and LR2 have 94% errors with 20% range in test phase. XGB, DT, LR2 models remained the highest performing models and XGB is the most robust and effective in predictions. Feature importances reveal the role of input parameters in prediction made by developed ML models. Dosage, humidity, UV light intensity remain important experimental factors. This study will impact positively in providing efficient models to estimate photocatalytic degradation rate of air contaminants using TiO2.
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| 14. |
- Javed, Sana, et al.
(författare)
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Biophysics and the nonlinear dynamics instigated by a special hormone
- 2020
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Ingår i: Progress in Biophysics and Molecular Biology. - : Elsevier BV. - 0079-6107 .- 1873-1732. ; 150, s. 62-66
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Forskningsöversikt (refereegranskat)abstract
- Calcitonin, a potent hypocalcemic hormone, plays a vital role in inhibiting osteoclastic activities and suppressing bone removal. The physiological characteristics of calcitonin have long been discussed, along a few recommending calcitonin as a vestigial hormone. The basis for this article is to discuss the role of low and high levels of calcitonin in normal and osteoprotic bone turnover. The effect of calcitonin on the receptor activator of nuclear factor kappa-ligand and osteoclasts has been demonstrated using numerical simulations. This behavior recommends that treatment of osteoporosis via calcitonin does not provide the required upshots. For effectiveness calcitonin must be advised along with a combined therapy like aspirin which agrees with the experimental results available in the literature.
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| 15. |
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| 16. |
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