Search results for: calcium channel blocker

Authors: Chui Ling Teng, R. Matsa

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We report a case with combined overdose of Lercanidipine (non-dihydropyridine calcium channel blocker), Quetiapine (Atypical antipsychotic), Ramipril and Duloxetine. A 66-year old male presented to the Emergency Department 12-hours after the ingestion of 1.2g Lercanidipine, 3g Quetiapine, 280mg of Ramipril and 420mg of Duloxetine. He describes lethargic, drowsiness and was unable to pass any urine since overdosed. He was found to be bradycardic, hypotensive and anuric. He had refractory hypotension and anuric despite fluid resuscitation, glucagon therapy and intravenous naloxone. His care was escalated to Intensive care, requiring noradrenaline, adrenaline, vasopressin, and hyperinsulinaemic euglycaemia therapy. He achieved haemodynamic stability and kidney function improved gradually with the support received. The total length of therapy lasted for 30 horus in which individual therapy was weaned down based on the requirement. He was then transferred to medical ward for further psychiatric assessment. This is a the first repored case of mixed overdose with lercanidipine, Quetiapine, Rampmipril and Duloxetine.

Keywords: calcium channel blocker, hyperinsulinaemic Euglycaemia therapy, lercanidipine, overdose

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Authors: Engin Metin Kaplan, Kemal Yaman

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In this study, the crash of a medium heavy vehicle onto a designed Road blocker (vehicle barrier) is studied numerically. Structural integrity of the Road blocker is studied by nonlinear dynamic methods under the loading conditions which are defined in the standards. NASTRAN® and LS-DYNA® which are commercial software are used to solve the problem. Outer geometry determination, alignment of the inner part and material properties of the road blocker are studied linearly to yield design parameters. Best design parameters are determined to achieve the most structurally optimized road blocker. Strain and stress values of the vehicle barrier are obtained by solving the partial differential equations.

Keywords: vehicle barrier, truck collision, road blocker, crash analysis

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Authors: Kathryn H. Yull, Lina T. Al Kury, Frank Christopher Howarth

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Cardiovascular diseases are frequently reported in patients with Type-1 Diabetes mellitus (DM). In addition to changes in cardiac muscle inotropy, electrical abnormalities are also commonly observed in these patients. In the present study, using streptozotocin (STZ) rat model of Type-1 DM, we have characterized the changes in L-type calcium channel activity in single atrioventricular nodal (AVN) myocytes. Ionic currents were recorded from AVN myocytes isolated from the hearts of control rats and from those with STZ-induced diabetes. Patch-clamp recordings were used to assess changes in cellular electrical activity in individual myocytes. Type-1 DM significantly altered the cellular characteristics of L-type calcium current (ICaL). A reduction in peak ICaL density was observed, with no corresponding changes in the activation parameters of the current. ICaL also exhibited faster time-dependent inactivation in AVN myocytes from diabetic rats. A negative shift in the voltage dependence of inactivation was also evident. These findings demonstrate that experimentally–induced type-1 DM significantly alters AVN L-type calcium channel cellular electrophysiology. The changes in ion channel activity may underlie the abnormalities in the cardiac electrical function that contribute to the high mortality levels in patients with DM.

Keywords: cardiac, ion-channel, diabetes, atrioventricular node, calcium channel

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Authors: James Patrick A. Diaz, Raul E. Ramboyong

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Background: Hypertensive response during maximal exercise test provides important information on the level of blood pressure control and evaluation of treatment. Method: A single center retrospective descriptive study was conducted among 117 young (aged 20 to 40) and middle age (aged 40 to 65) hypertensive patients, who underwent treadmill stress test. Currently on maintenance frontline medication either monotherapy (Angiotensin-converting enzyme inhibitor/Angiotensin receptor blocker [ACEi/ARB], Calcium channel blocker [CCB], Diuretic - Hydrochlorthiazide [HCTZ]) or combination therapy (ARB+CCB, ARB+HCTZ), who attained a maximal exercise on treadmill stress test (TMST) with hypertensive response (systolic blood pressure: male >210 mm Hg, female >190 mm Hg, diastolic blood pressure >100 mmHg, or increase of >10 mm Hg at any time during the test), on Bruce and Modified Bruce protocol. Exaggerated blood pressure response during exercise (systolic [SBP] and diastolic [DBP]), peak exercise blood pressure (SBP and DBP), recovery period (SBP and DBP) and test for ischemia and their antihypertensive medication/s were investigated. Analysis of variance and chi-square test were used for statistical analysis. Results: Hypertensive responses on maximal exercise test were seen mostly among female population (P < 0.000) and middle age (P < 0.000) patients. Exaggerated diastolic blood pressure responses were significantly lower in patients who were taking CCB (P < 0.004). A longer recovery period that showed a delayed decline in SBP was observed in patients taking ARB+HCTZ (P < 0.036). There were no significant differences in the level of exaggerated systolic blood pressure response and during peak exercise (both systolic and diastolic) in patients using either monotherapy or combination antihypertensives. Conclusion: Calcium channel blockers provided lower exaggerated diastolic BP response during maximal exercise test in hypertensive middle age patients. Patients on combination therapy using ARB+HCTZ exhibited a longer recovery period of systolic blood pressure.

Keywords: antihypertensive, exercise test, hypertension, hyperytensive response

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Authors: Omid Ghollipoor Bashiri, Farzam Hatefi

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Dichlorvos a synthetic organophosphate poisons are used as insecticide. These toxins can be used insecticides in agriculture and medicine for destruction and/or eradication of ectoparasites of animals. Studies have shown that Dichlorvos creation seizure effects in different animals. Amlodipine, dihydropyridine calcium channel blockers, widely used for treatment of cardiovascular diseases. Studies have shown that the calcium channel blockers are anticonvulsant effects in different animal models. The aim of this study was to determine the effect of Amlodipine on Dichlorvos-induced seizures in mice. In this experiment, the animals were received different doses of Amlodipine (2.5, 5, 10, 20 and 40 mg/ kg b.wt.) intraperitoneally 30 min before intraperitoneal injection of Dichlorvos (50 mg/kg b.wt). After Dichlorvos injection, clonic and tonic seizures, and finally was the fate was investigated. Results showed that Amlodipine dose-dependently reduced the severity of Dichlorvos-induced seizures, so that Amlodipine at a dose of 5mg (The lowest, p<0.05) and 40 mg/kg b.wt. (The highest, p<0.001) which had anticonvulsant effects. The anticonvulsant activity of Amlodipine suggests that possibly due to the antagonistic effect on voltage-dependent calcium channel.

Keywords: dichlorvos, amlodipine, seizures, mice

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Authors: Seok Woo Chang

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Aim: The objective of this study was to compare and evaluate the hydration products of commercial and experimental calcium silicate cement. Materials and Methods: The commercial calcium silicate cement (ProRoot MTA, Dentsply) and experimental calcium silicate cement (n=10) were mixed with distilled water (water/powder ratio = 20 w/w) and stirred at room temperature for 10 hours. These mixtures were dispersed on wafer and dried for 12 hours at room temperature. Thereafter, the dried specimens were examined with Scanning Electron Microscope (SEM). Electron Dispersive Spectrometry (EDS) was also carried out. Results: The commercial calcium silicate cement (ProRoot MTA) and experimental calcium silicate cement both showed precipitation of rod-like and globule-like crystals. Based on EDS analysis, these precipitates were supposed to be calcium hydroxide or calcium silicate hydrates. The degree of formation of these precipitates was higher in commercial MTA. Conclusions: Based on the results, both commercial and experimental calcium silicate cement had ability to produce calcium hydroxide or calcium silicate hydrate precipitates.

Keywords: calcium silicate cement, ProRoot MTA, precipitation, calcium hydroxide, calcium silicate hydrate

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Authors: Huafeng Wei

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Dementia in Alzheimer’s Disease (AD) is the number one cause of dementia internationally, without effective treatments. Increasing evidence suggest that disruption of intracellular calcium homeostasis, primarily pathological elevation of cytosol and mitochondria but reduction of endoplasmic reticulum (ER) calcium concentrations, play critical upstream roles on multiple pathologies and associated neurodegeneration, impaired neurogenesis, synapse, and cognitive dysfunction in various AD preclinical studies. The last federal drug agency (FDA) approved drug for AD dementia treatment, memantine, exert its therapeutic effects by ameliorating N-methyl-D-aspartate (NMDA) glutamate receptor overactivation and subsequent calcium dysregulation. More research works are needed to develop other drugs targeting calcium dysregulation at multiple pharmacological acting sites for future effective AD dementia treatment. Particularly, calcium channel blockers for the treatment of hypertension and dantrolene for the treatment of muscle spasm and malignant hyperthermia can be repurposed for this purpose. In our own research work, intranasal administration of dantrolene significantly increased its brain concentrations and durations, rendering it a more effective therapeutic drug with less side effects for chronic AD dementia treatment. This review summarizesthe progress of various studies repurposing drugs targeting calcium dysregulation for future effective AD dementia treatment as potentially disease-modifying drugs.

Keywords: alzheimer, calcium, cognitive dysfunction, dementia, neurodegeneration, neurogenesis

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Authors: Ravi Teja Mandapaka, Prasanna Kumar Kukkamalla

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Poor absorption of calcium, elevated levels in serum and loss of bone are major problems of astronauts during space travel. Supplementation of calcium could not reveal this problem. In normal condition only 33% of calcium is absorbed from dietary sources. In this paper effect of space environment on calcium metabolism was discussed. Many surprising study findings were found during literature survey. Clinical trials on ovariectomized mice showed that reduction of calcium particles to nano level make them more absorbable and bioavailable. Control of bone loss in astronauts in critical important In Fortification of milk with nana calcium particles showed reduces urinary pyridinoline, deoxypyridinoline levels. Dietary calcium and supplementation do not show much retention of calcium in zero gravity environment where absorption is limited. So, the fortification of foods with nano calcium particles seemed beneficial for astronauts during and after space travel in their speedy recovery.

Keywords: nano calcium, astronauts, fortification, supplementation

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Authors: Faisal A. Salih, V. V. Egorov

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Verapamil is a drug used in medicine for arrhythmia, angina, and hypertension as a calcium channel blocker. In this study, a Verapamil-selective electrode was prepared, and the concentrations of the components in the membrane were as follows: PVC (32.8 wt %), O-NPhOE (66.6 wt %), and KTPClPB (0.6 wt % or approximately 0.01 M). The inner solution containing verapamil hydrochloride 1 x 10⁻³ M was introduced, and the electrodes were conditioned overnight in 1 x 10⁻³ M verapamil hydrochloride solution in 1 x 10⁻³ M orthophosphoric acid. These studies have demonstrated that O-NPhOE and KTPClPB are the best plasticizers and ion exchangers, while both direct potentiometry and potentiometric titration methods can be used for the determination of verapamil hydrochloride in tablets and injection solutions. Normalized weights of verapamil per tablet (80.4±0.2, 80.7±0.2, 81.0±0.4 mg) were determined by direct potentiometry and potentiometric titration, respectively. Weights of verapamil per average tablet weight determined by the methods of direct potentiometry and potentiometric titration were" 80.4±0.2, 80.7±0.2 mg determined for the same set of tablets, respectively. The masses of verapamil in solutions for injection, determined by direct potentiometry for two ampoules from one set, were (5.00±0.015, 5.004±0.006) mg. In all cases, good reproducibility and excellent correspondence with the declared quantities were observed.

Keywords: verapamil, potentiometry, ion-selective electrode, lipophilic physiologically active amines

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Authors: Martina Šutovská, Marta Jošková, Ivana Kazimierová, Lenka Pappová, Maroš Adamkov, Soňa Fraňová

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Bronchial asthma is characterized by increased bronchoconstrictor responses to provoking agonists, airway inflammation and remodeling. All these processes involve Ca2+ influx through Ca2+-release-activated Ca2+ channels (CRAC) that are widely expressed in immune, respiratory epithelium and airway smooth muscle (ASM) cells. Our previous study pointed on possible therapeutic potency of CRAC blockers using experimental guinea pigs asthma model. Presented work analyzed complex anti-asthmatic effect of long-term administered CRAC blocker, including impact on allergic inflammation, airways hyperreactivity, and remodeling and mucociliary clearance. Ovalbumin-induced allergic inflammation of the airways according to Franova et al. was followed by 14 days lasted administration of CRAC blocker (3-fluoropyridine-4-carboxylic acid, FPCA) in the dose 1.5 mg/kg bw. For comparative purposes salbutamol, budesonide and saline were applied to control groups. The anti-inflammatory effect of FPCA was estimated by serum and bronchoalveolar lavage fluid (BALF) changes in IL-4, IL-5, IL-13 and TNF-α analyzed by Bio-Plex® assay as well as immunohistochemical staining focused on assessment of tryptase and c-Fos positivity in pulmonary samples. The in vivo airway hyperreactivity was evaluated by Pennock et al. and by organ tissue bath methods in vitro. The immunohistochemical changes in ASM actin and collagen III layer as well as mucin secretion evaluated anti-remodeling effect of FPCA. The measurement of ciliary beat frequency (CBF) in vitro using LabVIEW™ Software determined impact on mucociliary clearance. Long-term administration of FPCA to sensitized animals resulted in: i. Significant decrease in cytokine levels, tryptase and c-Fos positivity similar to budesonide effect; ii.Meaningful decrease in basal and bronchoconstrictors-induced in vivo and in vitro airway hyperreactivity comparable to salbutamol; iii. Significant inhibition of airway remodeling parameters; iv. Insignificant changes in CBF. All these findings confirmed complex anti-asthmatic effect of CRAC channels blocker and evidenced these structures as the rational target in the treatment of allergic bronchial asthma.

Keywords: allergic asthma, CRAC channels, cytokines, respiratory epithelium

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Authors: Nisha Singh, Neeru Adlakha

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Calcium signalling is one of the most important intracellular signalling mechanisms. A lot of approaches and investigators have been made in the study of calcium signalling in various cells to understand its mechanisms over recent decades. However, most of existing investigators have mainly focussed on the study of calcium signalling in various cells without paying attention to the dependence of calcium signalling on other chemical ions like inositol-1; 4; 5 triphosphate ions, etc. Some models for the independent study of calcium signalling and inositol-1; 4; 5 triphosphate signalling in various cells are present but very little attention has been paid by the researchers to study the interdependence of these two signalling processes in a cell. In this paper, we propose a coupled mathematical model to understand the interdependence of inositol-1; 4; 5 triphosphate dynamics and calcium dynamics in a myocyte cell. Such studies will provide the deeper understanding of various factors involved in calcium signalling in myocytes, which may be of great use to biomedical scientists for various medical applications.

Keywords: calcium signalling, coupling, finite difference method, inositol 1, 4, 5-triphosphate

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Authors: Salma Ahmed, Anil Kumar

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This paper develops and estimates a model for understanding the drivers and barriers for Omni-Channel retail. This study serves as one of the first attempt to empirically test the effect of various factors on Omni-channel retail. Omni-channel is relative new and evolving, we hypothesize three drivers: (1) Innovative sales and marketing opportunities, (2) channel migration, (3) Cross channel synergies; and three barriers: (1) Integrated sales and marketing operations, (2) Visibility and synchronization (3) Integration and Technology challenges. The findings from the study strongly support that Omni-channel effects exist between cross channel synergy and channel migration. However, it partially supports innovative sales and marketing operations. We also found the variables which we identified as barriers to Omni-channel retail have a strong impact on Omni-channel retail.

Keywords: retailing, multichannel, Omni-channel, emerging market

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Authors: Daniel C. S. Lim, Eric Y. M. Yeo, W. Y. Tan

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This paper presents an overview of how calcium interacts with the various essential nutrients within an environment of cellular and hormonal interactions for the purpose of increasing bioavailability to the human body. One example of such interactions can be illustrated with calcium homeostasis. This paper gives an in-depth discussion on the possible interactive permutations with various nutrients and factors leading to the promotion of calcium bioavailability to the body. The review hopes to provide further insights into how calcium supplement formulations can be improved to better influence its bioavailability in the human body.

Keywords: bioavailability, environment of cellular and hormonal interactions, nutritional combinations, synergistic

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Authors: Zhongyang Sun, Shu Zhang

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In osteoblasts, L-type voltage sensitive calcium channels (LTCCs), especially the Cav1.2 LTCCs, play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. Several lines of evidence have revealed that the density of bone is increased and the resorption of bone is decreased when these calcium channels in osteoblasts are activated. And numerous studies have shown that mechanical loading promotes bone formation in the modeling skeleton, whereas removal of this stimulus in microgravity results in a reduction in bone mass. However, the effect of microgravity on LTCCs in osteoblasts is still unknown. The aim of this study was to determine whether microgravity exerts influence on LTCCs in osteoblasts and the possible mechanisms underlying. In this study, we demonstrate that simulated microgravity substantially inhibits LTCCs in osteoblast by suppressing the expression of Cav1.2. Then we show that the up-regulation of miR-103 is involved in the down-regulation of Cav1.2 expression and inhibition of LTCCs by simulated microgravity in osteoblasts. Our study provides a novel mechanism of simulated microgravity-induced adverse effects on osteoblasts, offering a new avenue to further investigate the bone loss caused by microgravity.

Keywords: L-type voltage sensitive calcium channels, Cav1.2, osteoblasts, microgravity

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Authors: V. Surena, B. Nazemisalman, F. Noghrehkar

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Introduction: Gingival overgrowth (GO) is a common side effect involving users of antiepileptic, immunosuppressive and calcium channel blocker drugs. Cyclosporine and phenytoin are amongst the most widely used drugs associated with GO. Gingival fibroblasts seem to have a significant role in the production of certain enzymes after administration of the drugs contributing to GO. Previous studies have shown a higher prevalence of GO in children and adolescents. The aim of this study was to compare normal human gingival fibroblasts with those exposed to Cyclosporine or phenytoin in measuring the production levels of certain enzymes that could have a possible role in GO. Methods: samples were obtained from the gingival biopsies of seven adult and seven children and were cultured into plates. With the growth of fibroblast cells, they were treated with or without either Cyclosporine or phenytoin. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to determine the expressed levels of R-EGF, cathepsin B,L, Lysyl oxidase, COL1, TGF β1, MMP-1,2, and TIMP1. Results: according to RT-PCR analyses, the expressed levels of R-EGF, cathepsin B, L, Lysyl oxidase, COL1, TGF β1, MMP-1, 2 and TIMP1 were affected by Cyclosporine and phenytoin. TGF-β1, TIMP, Cathepsin B and EGF showed comparable values in the adult and pediatric groups. Conclusions: Different expressed levels of enzymes after treatment of the gingival fibroblasts of adults and pediatrics with phenytoin or Cyclosporine could be the reason for the higher severity of GO in children. More studies need to be performed on the pathogenesis of GO at different age groups.

Keywords: cyclosporine, fibroblasts, phenytoin, gingivae

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Authors: Faisal A. Salih

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Verapamil hydrochloride (Ver) is a drug used in medicine for arrythmia, angina and hypertension as a calcium channel blocker. For the quantitative determination of Ver in dosage forms, the HPLC method is most often used. A convenient alternative to the chromatographic method is potentiometry using a Verselective electrode, which does not require expensive equipment, can be used without separation from the matrix components, which significantly reduces the analysis time, and does not use toxic organic solvents, being a "green", "environmentally friendly" technique. It has been established in this study that the rational choice of the membrane plasticizer and the preconditioning and measurement algorithms, which prevent nonexchangeable extraction of Ver into the membrane phase, makes it possible to achieve excellent analytical characteristics of Ver-selective electrodes based on commercially available components. In particular, an electrode with the following membrane composition: PVC (32.8 wt %), ortho-nitrophenyloctyl ether (66.6 wt %), and tetrakis-4-chlorophenylborate (0.6 wt % or 0.01 M) have the lower detection limit 4 × 10−8 M and potential reproducibility 0.15–0.22 mV. Both direct potentiometry (DP) and potentiometric titration (PT) methods can be used for the determination of Ver in tablets and injection solutions. Masses of Ver per average tablet weight determined by the methods of DP and PT for the same set of 10 tablets were (80.4±0.2 and80.7±0.2) mg, respectively. The masses of Ver in solutions for injection, determined by DP for two ampoules from one set, were (5.00±0.015 and 5.004±0.006) mg. In all cases, good reproducibility and excellent correspondence with the declared quantities were observed.

Keywords: verapamil, potentiometry, ion-selective electrode, pharmaceutical analysis

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Authors: Marwa Ben Abdessalem, Amin Zribi, Ammar Bouallègue

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In this paper, a Joint Source Channel coding scheme based on LDPC codes is investigated. We consider two concatenated LDPC codes, one allows to compress a correlated source and the second to protect it against channel degradations. The original information can be reconstructed at the receiver by a joint decoder, where the source decoder and the channel decoder run in parallel by transferring extrinsic information. We investigate the performance of the JSC LDPC code in terms of Bit-Error Rate (BER) in the case of transmission over an Additive White Gaussian Noise (AWGN) channel, and for different source and channel rate parameters. We emphasize how JSC LDPC presents a performance tradeoff depending on the channel state and on the source correlation. We show that, the JSC LDPC is an efficient solution for a relatively low Signal-to-Noise Ratio (SNR) channel, especially with highly correlated sources. Finally, a source-channel rate optimization has to be applied to guarantee the best JSC LDPC system performance for a given channel.

Keywords: AWGN channel, belief propagation, joint source channel coding, LDPC codes

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Authors: Konstantinos Sotiriadis, Radosław Mróz

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In the present work the internal sulfate attack on pastes made from pure clinker phases was studied. Two binders were produced: (a) a binder with 2% C3A and 18% C4AF content; (b) a binder with 10% C3A and C4AF content each. Gypsum was used as the sulfate bearing compound, while calcium carbonate added to differentiate the binders produced. The phases formed were identified by XRD analysis. The results showed that ettringite was the deterioration phase detected in the case of the low C3A content binder. Carbonation occurred in the specimen without calcium carbonate addition, while portlandite was observed in the one containing calcium carbonate. In the case of the high C3A content binder, traces of thaumasite were detected when calcium carbonate was not incorporated in the binder. A solid solution of thaumasite and ettringite was found when calcium carbonate was added. The amount of C3A had not fully reacted with sulfates, since its corresponding peaks were detected.

Keywords: tricalcium aluminate, calcium aluminate ferrite, sulfate attack, calcium carbonate, low temperature

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Authors: Khelifi Mustapha, A. Moulay lakhdar, I. Elawady

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We will study the unequal error protection for VQ image. We have used the Reed Solomon (RS) Codes as Channel coding because they offer better performance in terms of channel error correction over a binary output channel. One such channel (binary input and output) should be considered if it is the case of the application layer, because it includes all the features of the layers located below and on the what it is usually not feasible to make changes.

Keywords: vector quantization, channel error correction, Reed-Solomon channel coding, application

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Authors: Jessica A. Soto-Bear, Virginia González-Vélez, Norma Castañeda-Villa, Amparo Gil

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Glutamate release of the cochlear inner hair cell (IHC) ribbon synapse is a fundamental step in transferring sound information in the auditory pathway. Otoferlin is the calcium sensor in the IHC and its activity has been related to many auditory disorders. In order to simulate secretion dynamics occurring in the IHC in a few milliseconds timescale and with high spatial resolution, we proposed an active-zone model solved with Monte Carlo algorithms. We included models for calcium buffered diffusion, calcium-binding schemes for vesicle fusion, and L-type voltage-gated calcium channels. Our results indicate that calcium influx and calcium binding is managing IHC secretion as a function of voltage depolarization, which in turn mean that IHC response depends on sound intensity.

Keywords: inner hair cells, Monte Carlo algorithm, Otoferlin, secretion

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Authors: Mansha Kotwani

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The specific spatio-temporal calcium concentration patterns are required by the fibroblasts to maintain its structure and functions. Thus, calcium concentration is regulated in cell at different levels in various activities of the cell. The variations in cytosolic calcium concentration largely depend on the buffers present in cytosol and influx of calcium into cytosol from ER through IP3Rs or Raynodine receptors followed by reuptake of calcium into ER through sarcoplasmic/endoplasmic reticulum ATPs (SERCA) pump. In order to understand the mechanisms of wound repair, tissue remodeling and growth performed by fibroblasts, it is of crucial importance to understand the mechanisms of calcium concentration regulation in fibroblasts. In this paper, a model has been developed to study calcium distribution in NRK fibroblast in the presence of buffers and ER flux with SERCA pump. The model has been developed for two dimensional unsteady state case. Appropriate initial and boundary conditions have been framed along with physiology of the cell. Finite element technique has been employed to obtain the solution. The numerical results have been used to study the effect of buffers, ER flux and source amplitude on calcium distribution in fibroblast cell.

Keywords: buffers, IP3R, ER flux, SERCA pump, source amplitude

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Authors: Seok Min Choi, Minho Bang, Seuong Yun Kim, Hyungmin Lee, Won-Gu Joo, Hyung Hee Cho

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The matrix cooling channel was used for gas turbine blade cooling passage. The matrix cooling structure is useful for the structure stability however the cooling performance of internal cooling channel was not enough for cooling. Therefore, we designed the rib configurations in the matrix cooling channel to enhance the cooling performance. The numerical simulation was conducted to analyze cooling performance of rib configured matrix cooling channel. Three different rib configurations were used which are vertical rib, angled rib and c-type rib. Three configurations were adopted in two positions of matrix cooling channel which is one fourth and three fourth of channel. The result shows that downstream rib has much higher cooling performance than upstream rib. Furthermore, the angled rib in the channel has much higher cooling performance than vertical rib. This is because; the angled rib improves the swirl effect of matrix cooling channel more effectively. The friction factor was increased with the installation of rib. However, the thermal performance was increased with the installation of rib in the matrix cooling channel.

Keywords: matrix cooling, rib, heat transfer, gas turbine

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Authors: Jiji Jose, R. Narayanacharyulu, Molly Mathew, Jisha Prems

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Introduction: Lercanidipine hydrochloride (LD), an effective calcium channel blocker, widely used for the treatment of chronic stable angina and hypertension seems to be potential transdermal therapeutic system candidate, mainly due to its low oral bio availability, short half life and high first-pass metabolism. Objective: To develop transdermal therapeutic systems for LD and to evaluate its in vivo performance in rabbits. Methodology: Transdermal patches of LD were formulated using the polymer blend of eudragit RL100 (ERL) and polyvinyl pyrolidone (PVP) by casting method Propylene glycol (PG) and tween 80 were used as plasticizer and permeation enhancer respectively. The pharmaco kinetic parameters of LD after the administration of transdermal patches was compared with that of oral administration. The study was carried out in a two way crossover design in male New Zealand albino rabbits. Results: The formulation with ERL: PVP ratio 1:4 with 15% w/w PG as plasticizer and 4% w/w tween 80 as permeation enhancer showed the best drug release results. The pharmacokinetic parameters such as Cmax, tmax, mean residence time (MRT) and area under the curve (AUC 0-∞) were significantly different following transdermal administration compared to oral administration. The terminal half life of transdermally administered LD was found to similar that of oral administration. A sustained drug release over a period of 24 hrs was observed after transdermal administration. Conclusion: The fabricated transdermal delivery system have the potential to provide controlled and extended drug release, better bio availability and thus, this may improve the patient compliance.

Keywords: transdermal therapeutic system, lercanidipine hydrochloride, eudragit, skinpermeation

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Authors: Achmad Buhori, Reza Imam Pratama, Tissa Wiraatmaja, Wanti Megawati

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Data from many countries indicates that there is a marked increase of dental caries. The increases in caries appear to occur in lower socioeconomic groups. It is possible that the benefits of prevention of dental caries are not reaching these groups. However, there is a way to decrease dental caries by adding 5% of bromelain and calcium as an active agent in toothpaste. Bromelain can break glutamine-alanine bond and arginine-alanine bond which is a constituent of amino acid that causes dental plague which is one of the factors of dental caries. Calcium help rebuilds the teeth by strengthening and repairing enamel. Bromelain can be found from the extraction of pineapple (Ananas comosus) cobs (88.86-94.22 % of bromelain recovery during extraction based on the enzyme unit) and calcium can be taken from eggshell (95% of dry eggshell consist of calcium). The aim of this experiment is to make a toothpaste which contains bromelain and calcium as an effective, cheap, and healthy way to decrease dental caries around the world.

Keywords: bromelain, calcium, dental caries, dental plague, toothpaste

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Authors: Seung-Jun Yu, Yong-Jun Kim, Jung-In Baik, Hyoung-Kyu Song

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In this paper, a dual-hop relay based on channel state is studied. In the conventional relay scheme, a relay uses the same modulation method without reference to channel state. But, a relay uses an adaptive modulation method with reference to channel state. If the channel state is poor, a relay eliminates latter 2 bits and uses Quadrature Phase Shift Keying (QPSK) modulation. If channel state is good, a relay modulates the received symbols with 16-QAM symbols by using 4 bits. The performance of the proposed scheme for Symbol Error Rate (SER) and throughput is analyzed.

Keywords: adaptive transmission, channel state, dual-hop, hierarchical modulation, relay

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Authors: Ali Abdelnabi, Nermeen Hamza

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Coral calcium is a boasting natural product and dietary supplement which is considered a source of alkaline calcium carbonate, this study is a comparative study, comparing the remineralization effect of the new product of coral calcium with that of nano-hydroxyapatite. Methodology: a total of 35 extracted molars were collected, examined and sectioned to obtain 70 sound enamel discs, all discs were numbered and examined by scanning electron microscope coupled with Energy Dispersive Analysis of X-rays(EDAX) for mineral content, subjected to artificial caries, and mineral content was re-measured, discs were divided into seven groups according to the remineralizing agent used, where groups 1 to 3 used 10%, 20%, 30% nanohydroxyapatite gel respectively, groups 4 to 6 used 10%, 20%, 30% coral calcium gel and group 7 with no remineralizing agent (control group). All groups were re-examined by EDAX after remineralization; data were calculated and tabulated. Results: All groups showed a statistically significant drop in calcium level after artificial caries; all groups showed a statistically significant rise in calcium content after remineralization except for the control group; groups 1 and 5 showed the highest increase in calcium level after remineralization. Conclusion: coral calcium can be considered a comparative product to nano-hydroxyapatite regarding the remineralization of enamel initial carious lesions.

Keywords: artificial caries, coral calcium, nanohydroxyapatite, re-mineralization

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Authors: A. Zahra, G. de Cesare, D. Caputo, A. Nascetti

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PDMS (Polydimethylsiloxane) polymer is a suitable material for biological and MEMS (Microelectromechanical systems) designers, because of its biocompatibility, transparency and high resistance under plasma treatment. PDMS round channel is always been of great interest due to its ability to confine the liquid with membrane type micro valves. In this paper we are presenting a very simple way to form round shape microfluidic channel, which is based on reflow of positive photoresist AZ® 40 XT. With this method, it is possible to obtain channel of different height simply by varying the spin coating parameters of photoresist.

Keywords: lab-on-chip, PDMS, reflow, round microfluidic channel

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Authors: J. Suwanprateeb, F. Thammarakcharoen

Abstract:

Calcium phosphate coating (CaP) has been employed for protein delivery, but the typical direct protein adsorption on the coating led to low incorporation content and fast release of the protein from the coating. By using bovine serum albumin (BSA) as a model protein, rapid biomimetic co-precipitation between calcium phosphate and BSA was employed to control the distribution of BSA within calcium phosphate coating during biomimetic formation on titanium surface for only 6 h at 50 oC in an accelerated calcium phosphate solution. As a result, the amount of BSA incorporation and release duration could be increased by using a rapid biomimetic co-precipitation technique. Up to 43 fold increases in the BSA incorporation content and the increase from 6 h to more than 360 h in release duration compared to typical direct adsorption technique were observed depending on the initial BSA concentration used during co-precipitation (1, 10, and 100 microgram/ml). From X-ray diffraction and Fourier transform infrared spectroscopy studies, the coating composition was not altered with the incorporation of BSA by this rapid biomimetic co-precipitation and mainly comprised octacalcium phosphate and hydroxyapatite. However, the microstructure of calcium phosphate crystals changed from straight, plate-like units to curved, plate-like units with increasing BSA content.

Keywords: biomimetic, Calcium Phosphate Coating, protein, titanium

Procedia PDF Downloads 348

Authors: Masoud Baghalian, Musa Arshad

Abstract:

In order to investigate the effect of foliar application of calcium chloride on the resistance of fruits such as Red and Golden Lebanese apple varieties to blue mold, a split plot experiment in time and space, based on accidental blocks, with three replications under foliar application were done (Control, one in a thousand, two in thousands) and the results of the variance analysis showed that there is a significant difference between the levels of foliar and variety at 5% level and between time, there is significant difference in interaction of variety × time and three way interaction of foliar×variety×time, at 1% level. The highest resistance to the blue mold disease in foliar application was observed at two in thousands calcium (calcium chloride) level.

Keywords: apple, blue mold, foliar calcium, resistance

Procedia PDF Downloads 235

Authors: T. Mdzinarashvili, M. Khvedelidze, E. Shekiladze, S. Chinchaladze, M. Mdzinarashvili

Abstract:

The study of the possible interaction between calcium ions and lipids is of great importance for the studies of complexes of calcium drug-carrying nanoparticles. We prepared calcium-containing complex liposomes from Dipalmitoylphosphatidylcholine (DPPC) lipids and studied their thermodynamic properties. In calorimetric studies, we determined that the phase transition temperature of these complexes is close to 420 C. It was shown that both hydrophobic and hydrophilic connections take part in the formation of calcium nanoparticles. We were interested in hydrophilic bonds represented by hydrogen bonds. We have shown that these hydrogen bonds are formed between the phospholipid heads, and the main contributor is the oxygen atoms in the phosphoric acid residues. In addition, based on the amount of heat absorbed during the breaking of hydrogen bonds formed between calcium-containing nanoparticle complexes, it can be concluded that the hydrogen atoms in the head of DPPC lipids form hydrogen bonds between P=O and P-O groups of phosphate. The energy of heat absorption measured by the calorimeter is of the order obtained by breaking the hydrogen bonds we have specified. Thus, we conclude that our approach to the model of liposome formation from lipids is correct. As for calcium atoms - due to the fact that it is present in the form of positive ions in the liposome, they will connect only with negatively charged phosphorus ions.

Keywords: DPPC, liposomes, calcium, complex nanoparticles

Procedia PDF Downloads 67