Quantitative assessment of covariants of root canal treatment efficacy in human teeth

Clinically relevant cofactors that can demonstrate aspects of root canal treatment quality are of importance to clinicians, researchers and dental instrument manufacturers. Endodontics has been one of the most developing fields of dental science in recent years. There have been new instruments, materials, and methods introduced, which have been very rapidly adopted since most facilitate the root canal treatment process. Considering the current rate of technological developments and the long-term follow-ups required for clinical evaluation of root canal treatment success, clinical trials are not feasible for assessing every variable in treatment. In search of cofactors that could be used to demonstrate the efficacy and quality of a root canal treatment, the effect of surface roughness was investigated in the present thesis. Clinical relevance of surface roughness and its effect on endodontic treatments was assessed in the second chapter. This aim was achieved by comparing biofilm formation on rough and smooth dentine surfaces. Enterococcus faecalis was the microorganism tested to form biofilms on these surfaces because of its role as one of the most important endodontic pathogens in persistent endodontic infections. A novel methodology utilizing flow cytometry to quantify bacteria attached to the surfaces was designed for this experiment. The results showed that rough surfaces harboured a significantly higher number of bacteria compared to smooth surfaces. This indicated that achieving a final smooth surface in root canal treatment reduces the chance of bacterial biofilm formation. Considering the wide range of instrument designs and functions that are used in endodontic treatments, the results demonstrated the necessity for further investigations into their effect on a treated canal's final surface quality. Practical aspects of root canal treatment that may be effective on the canal surface roughness were the focus of the next experiments of this thesis. The third chapter compares the effect of two different filing motions, continuous rotary and adaptive reciprocation, on root canal surface roughness. Continuous rotation and reciprocation are the two most frequently used filing techniques in root canal instrumentation. In this experiment, a filing system that was compatible to work in both rotary and adaptive reciprocation modes was used to answer whether filing motion can affect surface roughness of a root canal. Experiments showed that surface roughness was significantly higher overall in the root canals of teeth prepared with adaptive reciprocation compared to continuous rotary. The results of this chapter showed that roughness of the root canal is a cofactor that can be modified by the clinician. Treatment strategies with different techniques can be implemented even while using identical instruments to achieve smoother treated surfaces. Based on the findings of this study, using a continuous rotary system to prepare canals or to finish the cleaning and shaping stage of a root canal treatment can be beneficial to reducing roughness of the canal surface. Differences between filing systems consists of differences in a mixture of variables including alloy, surface treatment, cross-section, taper, motion, design, etc. The fourth chapter in this series was aimed to evaluate the effect of three different filing systems with different concepts, on the final root canal surface quality. Cleaning and shaping was carried out on teeth with either a single-file reciprocating (Reciproc), continuous rotary (HyFlex EDM) or oscillating self-adjusting file (SAF) system. The results from this chapter showed that the three completely different filing systems resulted in similarly rough root canal surfaces. The high level of roughness in all groups suggested that the three filing systems tested in this experiment were relatively aggressive. File wear results in reduced cutting efficiency and aggressiveness. Since each file undergoes a life cycle and it is eventually worn out, the fifth chapter of this thesis was designed to assess how the effect of file wear translates into changes on the treated root canal surface roughness. In order to evaluate the impact of file wear effectively, Reciproc single-file reciprocating instruments were used for this study. Reciproc files endure the same stress that is usually distributed among a number of files in multi-file systems. This study showed that the amount of wear during three uses, which is within the range of use recommended by the manufacturer, does not affect the final root canal surface roughness. Without consideration of safety of these files in terms of file separation risk, these files can be used up to three times while expecting a similar treatment outcome. However, similar to the previous study, these files left a relatively rough surface in all cases. The key findings in the present thesis were that root canal surface roughness is an effective and modifiable cofactor that can be used to determine the quality of root canal instrumentation and the performance of the instruments used. The two new methodologies developed can be used to test other available endodontic instruments and techniques. These methods can provide a foundation for generating comparable and quantitative data regarding the roughness values and thresholds associated with biofilm formation and different endodontic instruments. Standard levels can be set for future instrument designs once enough research is available regarding the performance of the current instruments and the ideal levels of surface roughness

Enzymatic Synthesis of Theanine in the Presence of L-glutaminase Produced by Trichoderma koningii

Background and Objective: Since ancient times, it has been said that drinking green tea brings relaxation. The substance that is responsible for a sense of relaxation is theanine. Theanine (γ-glutamylethylamide) is a unique non-protein amino acid. It gives an umami taste and a unique flavor to the tea, and has many physiological and pharmaceutical effects such as anti-tumor, anti-cancer, neuro-protective, anti-hypertensive and anti-obesity effects; it may further help in relaxation and increase focus. So this compound is essential for human body; however, it is not synthesized in the body and should be administrated orally. In the present study, the enzymatic biosynthesis of theanine was examined in the presence of Ethylamine and L-glutamine, and for the first time the enzyme was produced by the fungal strain Trichoderma koningii. Material and Methods: At first, solid state fermentation was carried out for the production of L-glutaminase by the fungal strain Trichoderma koningii using sesamum oil cake as the solid substrate. Then the biosynthesis of theanine was performed in the presence of extracted enzyme solution, and ethylamine and L-glutamine as substrates. The concentration of effective parameters, namely L-glutamine and ethylamine, and the volume of enzyme solution on theanine production were evaluated based on the response surface methodology coupled with central composite design. 16 experiments were designed by the design expert software and carried out to examine the changes of theanine concentration with changes in the concentration of ethylamine and L-glutamine and the volume of enzyme solution. Results and Conclusion: This investigation indicated simultaneous synthesis of theanine as well as hydrolysis of L-glutamine and L-glutamic acid. Selected independent variables (including ethylamine concentration, L-glutamine concentration and enzyme solution volume) were effective on theanine concentration. Increase of enzyme solution volume had a significant effect on theanine concentration. The highest theanine concentration (43 mM) was obtained at the ethylamine concentration of 0.9 M, L-glutamine concentration of 0.3 M and enzyme solution of 3 ml. Conflict of interest: The authors declare no conflict of interest

Prevalence, antibiotic-resistance properties and enterotoxin gene profile of Bacillus cereus strains isolated from milk-based baby foods

Purpose: To investigate the prevalence, distribution of enterotoxins and antibiotic resistance of B. cereus in milk-based infant foods.Methods: Three-hundred milk-based infant foods were collected and immediately transferred to the laboratory. Samples were cultured and B. cereus isolates were also confirmed using polymerase chain reaction (PCR)-based detection of gyrB gene. B. cereus strains were subjected to disk diffusion and PCR-based detection of enterotoxigenic genes.Results: Prevalence of B. cereus in infant foods was 3 %. Contamination was in the range of 12.5 – 41.5 CFU/g. Brand D had the highest prevalence of B. cereus (6.2 %). NheA (88.8 %), nheC (55.5 %) and entFM (55.5 %) were the most commonly detected enterotoxigenic genes. Bacteria showed the highest prevalence of resistance against penicillin (100 %), tetracycline (77.7 %) and oxacillin (66.6 %). Prevalence of resistance against two antibiotics were 100 %.Conclusion: Considerable prevalence of resistant and toxigenic B. cereus and high consumption of milk-based infant foods in Iran, represent an important public health issue which should be considered for further preventive approaches.Keywords: Prevalence, Bacillus cereus, Antibiotic resistance, Enterotoxigenic genes, Milk-based infant foo

VacA, CagA, IceA and OipA Genotype Status of Helicobacter pylori Isolated from Biopsy Samples from Iranian Dogs

Purpose: To investigate the state of vacA, cagA, oipA and iceA genotypes of H. pylori isolated from gastric biopsy samples of dogs.Methods: A total of 240 gastric biopsy samples were taken from 240 dogs using gastric endoscope. All the samples were cultured and H. pylori-positive samples were analyzed for the presence of various genotypes using polymerase chain reaction (PCR).Results: Thirteen out of 240 (5.41 %) samples were positive for H. pylori with a higher prevalence of the bacterium in dogs with gastric ulcer (6.36 %). The most commonly detected genotypes were vacA s1a (53.84 %), cagA (46.15 %) and vacA m2 (38.46 %). Total prevalence of iceA1, iceA2 and oipA genotypes were 23.07, 10.8 and 10.81 %, respectively. M2s1a (30.76 %), m1am2 (30.76 %) and m1as1a (23.07 %) had the highest prevalence among other detected combined genotypes. Twenty-two different genotypic combinations were detected with higher prevalence of s1a/cagA+/iceA1/oipA- (23.07 %), m2/cagA+/iceA1/oipA- (23.07 %), and s1b/cagA+/iceA1/oipA- (15.38 %) genotypes.Conclusion: The presence of similar genotypes in H. pylori strains of gastric biopsy samples of dogs and those of human clinical specimens suggest that dogs may be the source of the bacterium. Proper handwashing and avoidance contact with feces and saliva of dogs are recommended to prevent transmission of H. pylori.Keywords: Helicobacter pylori, Genotype, Genotyping, Gastric biopsy, Iranian dog

MODELLING OF INTERACTION BETWEEN PLASTICITY AND MARTENSITIC PHASE TRANSFORMATION IN SHAPE MEMORY ALLOYS

Ph.DDOCTOR OF PHILOSOPH

Joint Antenna Selection and Power Allocation in Massive MIMO Systems with Cell Division Technique for MRT and ZF Precoding Schemes

One of the most important challenges in the fifth generation (5G) of telecommunication systems is the efficiency of energy and spectrum. Massive multiple-input multiple-output (MIMO) systems have been proposed by researchers to resolve existing challenges. In the proposed system model of this paper, there is a base station (BS) around which several users and an eavesdropper (EVA) are evenly distributed. The information transmitted between BS and users is disrupted by an EVA, which highlights the importance of secure transfer. This paper analyzes secure energy efficiency (EE) of a massive MIMO system, and its purpose is to maximize the secure EE of the system. Several scenarios are considered to evaluate achieving the desired goal. To maximize the secure EE, selecting optimal number of antennas and cell division methods are employed. Each of these two methods is applied in a system with the maximum ratio transmission (MRT) and the zero forcing (ZF) precodings, and then the problem is solved. Maximum transmission power and minimum secure rate for users insert limitations to the optimization problem. Channel state information (CSI) is generally imperfect for users in any method, while CSI of the EVA is considered perfect as the worst case. Four iterative algorithms are designed to provide numerical assessments. The first algorithm calculates the optimal power of users without utilizing existing methods, the second one is related to the cell division method, the third one is based on the strategy of selecting optimal number of antennas, and forth one is based on a hybrid strategy

A finite deformation Cosserat continuum model for uncured carbon fibre composites

A new three-dimensional, finite deformation Cosserat continuum model for the elastic response of uncured carbon fibre composites is presented. The new composite process model captures the bending contribution of bundles of fibres at the microscale within a mesoscale continuum description of a composite ply. This is achieved by introducing higher-order, independent rotational degrees of freedom into the continuum formulation. This paper demonstrates the inclusion of such mechanics is essential to accurately model various bending responses induced during typical composite manufacturing processes. This includes large deformation forming, finite strain consolidation and wrinkling (the formation of an unwanted defect). If such mechanics are not included, the literature demonstrates the resulting finite element solutions have a pathological dependence on the mesh size. As a result, simulations require users to fit mesh-dependent material parameters, which limits confidence in their predictive capabilities. The Cosserat continuum, which can be seen as a form of the regularised continuum model, overcomes these challenges. In particular, this paper presents details of the finite element formulation of the new continuum model within a nonlinear Taylor–Hood Cosserat Element. Implementation details of embedding this new element within the commercial code Abaqus are given, alongside a series of increasingly complex validation simulations. Notably, the examples include modelling the formation of internal fibre wrinkles and large deformation forming, which involves complex ply-to-ply and tool-to-ply contact. The paper concludes by describing: (1) how the elastic Cosserat model can be integrated into existing large deformation process models in the literature. The approach set out readily allows researchers to include the important effects of resin flow, cure kinetics and temperature distribution, not considered in this contribution, and (2) how it is envisaged that the ply scale model can be naturally scaled up to large laminate scale simulation using mathematical upscaling techniques

Comparison of Serum Zinc Levels among Children with Simple Febrile Seizure and Control Group: A Systematic Review

How to Cite This Article: Nasehi MM, Sakhaei R, Moosazadeh M, Aliramzany M. Comparison of Serum Zinc Levels among Children with Simple Febrile Seizure and Control Group: A Systematic Review. Iran J Child Neurol. 2015 Winter;9(1):17-24 .AbstractObjectiveSeveral factors are involved in the etiology of febrile seizure (FS), among themis zinc (Zn), which has been discussed in various studies. The present systematic review compares Zn levels in children with FS and a control group.Materials & MethodsWe searched keywords of febrile seizure, febrile convulsion, children, childhood,fever, trace elements, risk factor, predisposing, zinc, Zn, and epilepsy in thefollowing databases: SCOPUS, PubMed, and Google Scholar. The quality ofresearch papers was assessed using a checklist. Data was extracted from primarystudies based on demographic variables and amounts of Zn in case and controlgroups.ResultsTwenty primary studies were entered in the present study. Of which, eighteenstudies, reported that Zn serum levels were significantly lower in the case group(patients with FS) than the control group.ConclusionThe present systematic review indicated that Zn is one factor for predicting FS.A low level of this element among children can be regarded as a contributingfactor for FS, a conclusion with a high consensus among different studies carriedout in different parts of the world. ReferencesHeydarian F, Ashrafzadeh F, Ghasemian A. Serum ZINC level in Patients with simple febrile seizure. Iran J Child Neurology 2010; 14(2):41-44.Mahyar A, Pahlavan AA, Varasteh-Nejad A. Serum zinc level in children with febrile seizure. Acta Medica Iranica 2008; 46(6): 477-80.Kunda GK, Rabin F, Nandi ER, Sheikh N, Akhter S. Etiology and Risk Factors of Febrile Seizure – An Update. Bangladesh J Child Health 2010; 34 (3):103-112.Abbaskhaniyan A, Shokrzadeh M, Rafati MR, Mashhadiakabr M, Arab A, Yazdani J. 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Evaluation of antioxidant activity of the purified peptides from hydrolysis of rotifer (Brachionus plicatilis)

Rotifers are an important group of zooplankton in aquatic ecosystems that contain relatively high amounts of unsaturated fatty acids, proteins and peptides. Rotifers, especially Brachionus plicatilis species, are one of the important live food sources for marine fish larvae in aquaculture. The aim of this study was to evaluate the antioxidant activities of purified peptides from B. plicatilis. Antioxidant peptides of the B. plicatilis have been hydrolyzed by Alcalase, α¬Chymotrypsin, Papain, Neutrase, Pepsin, and Trypsin. Their antioxidant activity was evaluated by the free radical inhibitory effect of diphenylpicrylhydrazyl (DPPH). Also the sequential chromatography method was used for extraction and purification of the peptides. The results showed that peptides obtained from the pepsin hydrolysate have a higher inhibitory effect than other peptides. Pepsin showed 58% inhibitory effect in 0.015 mM DPPH. Finally, the pepsin hydrolysate constitutes were purified and isolated by gel-filtration chromatography (Sephadex G-250) and reverse-phase liquid chromatography on Eurospher C18 column (250×4.6 mm), respectively. The results of this study have been recognized the high antioxidant activities of extracted hydrolysate from B. plicatilis and their feasibility of using them in food industries as a food complement