Silica fume concrete in hot and temperate environments

his investigation deals with the influence of hot and temperate curing environments on the hardened properties of concrete and mortar mixes. Condensed silica fume was blended with OPC as a potential alternative cementitious material to plain OPC for use in the hot Iraqi climate, in an attempt to find a cement combination that would overcome some of the durability problems experienced when using a plain OPC concrete in such an environment. Throughout the investigation two curing environments were used: the first simulating the UK temperate climate and the second simulating the hot Iraqi climate. Temperature and humidity were varied to simulate day and night time. The first stage of the experimental study was the development of a mix design method capable of producing an OPC-CSF cement concrete of a medium workability and a specific 28-days compressive strength ranging between 25 to 55 MPa, both with and without superplasticizer. Three grades of concrete strength were chosen (25,40 and 55 MPa) and the effect of four cement replacement levels (5,10,15 and 20%) of silica fume on concrete compressive strength was assessed. Test results showed that CSF was relatively more effective in lean mixes than in rich ones. Compressive strength of CSF concrete increased with increasing CSF percentages for both normal and superplasticized mixes up to an optimum levels of 10-15% and 15-20%, respectively. The amount of OPC (kg/m`3) necessary to bring a change in compressive strength of 1MPa was also determined and the theoritical blend proportions of OPC-CSF necessary to produce 28-day compressive strength equivalent to the plain OPC mixes were determined from the produced data above. The theoretical blend proportions were examined experimentally and the data were used to establish the relationship between strength and water/cementitious ratio for the blend mixes with and, without superplasticizer. Results showed that this basic relationship had changed quantitatively but not qualitatively when CSF was used. A cost study using current OPC and CSF material costs -was performed in an attempt to determine'the- most economic blend proportions. A total of eleven different concrete -mixes were selected to study the effect of curing environment (hot and temperate), initial curing time (0,1,3 and`-7 days) and curing method (water and polythene sheeting) on the compressive strength, permeability and absorption properties of the CSF concretes. Tests were carried out at 3,7, '14, 28,56,90 and 180 days of age. In addition five different mortar, mixes were used to examine the effect of curing environment (temperate and hot) an the *permeability, pore size distribution and durability to magnesium sulphate attack. Test results showed that hot Iraqi curing environment was favourable to the early-age strength, absorption and permeability of plain OPC mixes. However, - the later-age properties were significantly lower than those obtained for concretes cured in a temperate UK environment. For plain OPC mixes a critical curing period of 3 days was found under both temperate and hot environment. For the CSF blend mixes critical curing periods for the temperate and hot environment were found to be 3 and 1 day respectively. Results also reveal the importance of curing specimens immediately after casting for one day. Research work has also confirmed the superiority of water curing over polythene sheeting in a temperate environment for the rich plain OPC and CSF mixes. However, there was no significant difference between water and polythene for lean mixes. The reduction in , permeability and absorption properties of CSF mixes cured in a both temperate and hot environments is thought to be due to the changes in the pore structure brought about by the use of silica fume. Combining CSF with OPC was found to increase the percentages and volume of fine pores at the expense-of coarse pores. This effect may be described as a "refining" effect. Finally, the performance of CSF mortar mixes cured in a temperate and hot environment and their resistance to magnesium sulphate attack was significantly better than the plain OPC ones

Bioactive glass composite for orthodontic adhesives - Formation and characterisation of apatites using MAS-NMR and SEM.

OBJECTIVES: To study the dissolution and fluoroapatite (FAP) formation of a new bioactive glass (BAG)-resin adhesive in an acidic solution in reference to neutral solutions, using the magic angle spinning-nuclear magnetic resonance (MAS-NMR) and the scanning electron microscopy (SEM). METHODS: BAG composite disks (n = 90) were prepared from, novel fluoride-containing BAG-resin. Three sample groups (n = 30) of the disks were immersed in Tris buffer pH = 7.3 (TB), neutral artificial saliva pH = 7 (AS7) and acidic artificial saliva pH = 4 (AS4) at ten time points (from 6 h to 6 months). Half of the immersed disks at each time point were crushed into a powder and investigated by the solid state MAS-NMR. SEM studies were undertaken by embedding the other half of the immersed disk in a self-cure acrylic where the fracture surface was imaged. RESULTS: MAS-NMR results show that the BAG composite degraded significantly faster in AS4 compared to TB and AS7. At the end of the immersion period (6 months), around 80% of the glass particles in AS4 had reacted to form an apatite, evidenced by the sharp peak at 2.82 ppm in 31P signals compared to a broader peak in TB and AS7. It also shows evidence of fluorapatite (FAP) formation, indicated by 19F signal at -103 ppm, while signal around -108 ppm indicated the formation of calcium fluoride, from the excess Ca2+ and F- especially on longer immersion. SEM images confirm higher degradation rate of the BAG composite in AS4 and reveal the impact of time on the dissolution of more glass particles. The images also indicate apatite formation around the glass particles in TB and AS4, while it forms predominantly over the disk surface in AS7. SIGNIFICANCE: BAG composite demonstrate smart reactivity in response to pH change which has a potential clinical benefit against demineralization and promoting remineralisation to form more stable fluorapatites

The effect of inflammatory cytokines on occurrence of retained placenta in cattle

Background: In simple terms, retained placenta is a common issue after parturition in cattle that can affect their reproductive ability. In pregnancies with fetal growth restriction (FGR), the placenta has low anti-inflammatory cytokines and high pro-inflammatory cytokines. By looking at variations in cytokine levels in the blood, we can diagnose the condition. The focus of a recent study was to examine the role of some interleukins  (Interleukins -10, Interleukins -6, Interleukins -1β), C-reactive protein (CRP) and Tumor Necrosis Factor (TNF)-α, in retained placenta occurrence in cattle.Methods: The study involved 40 cows, aged 3-8 years in the Salah-Din province. Each animal suffered from retained placenta also eleven healthy cows served as the control group in a period of January to August 2022. The blood serum was analyzed using enzyme immunoassay techniques (ELIZA) to measure the levels of IL-10, IL-6, IL-1β, CRP and TNF-α.Results: Serum levels of IL-10, IL-6, IL-1β, CRP and TNF-α showed a significant increase in cows experiencing retained fetal membranes compared to healthy cows (2.31±0.11 vs 1.41 ±0.07) (10.48±0.24 vs 5.40±0.19), (13.6±2.1 vs 4±0.9), (0.9±0.02 vs 0.32±0.04) and (60.1 ± 12.79 vs 29.5 ± 16.58) respectively.Conclusion: from the present study we conclude that IL10, IL6, IL1β and TNFα play an essential component in retained placenta incidence, and  the estimation levels of these parameters in serum may be considered good indicator for occurrence in cattle. RT-PCR revealed increased expression of SDHA genes in the maternal compartment of the placenta.Keywords: Retained placenta; Cytokines; C-reactive protein 

Analysis of Heavy Metals in Selected Cigarettes and Syrupy Tobacco (Mu'assel) Brands Smoking in Baghdad Market Iraq

Smoking related diseases can be attributed to the inhalation of many different toxins including heavy metals which have a host of detrimental health effects. The current study reports the levels of cadmium (Cd) , Nickel (Ni), cupper(Cu), Iron(Fe), Zinc(Zn) and lead(Pb) in cigarettes and syrupy tobacco(Mu՝ assel)obtained from Baghdad – Iraq Markets.The mean concentrations of Cd,Ni,Cu,Fe,Zn and Pb were (26),(0.29),(0.42),(1000),(45.3)and (0.26) ppm  repectively .There were some differences in metal concentrations of cigarette brands producted by different manufacturers suggesting differences in the source of tobaccos used by different companies . For (Ni) , there were significant pairwis differences between Aspin and Al AMASE (Bountry) Mu՝ assel brands. For (Fe)AlAmase (Bountry)Brands had higher levels than Pine brands. Levels of (Cd) and (Pb) did not differ significantly across manufacturer group. Beacouse of the varity of toxic heavy metals in different brands of cigarette tobacco and their numerous negative health effects metal content in cigarette tobacco should be reduced. Keywords: Metal, Toxicity, Tobacco, smoking, Mu՝asse

Clinical significance of the lipid profile, neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) in different rheumatic disease patients

Objectives. To assess the lipid profile, neutrophil-lymphocyte ratio(NLR) and platelet-lymphocyte ratio(PLR) in different rheumatic diseases and to study their relation to disease activity and/or severity. Patients and methods. 257 patients (47 rheumatoid arthritis (RA), 100 systemic lupus erythematosus (SLE), 49 systemic sclerosis (SSc), 33 axial spondyloarthritis (axSpA) and 28 vasculitis (21with primary vasculitis and 7 with Behçet’s disease ‘BD’) and 70 controls were recruited. The disease activity and/or severity were assessed for each disease. The lipid profile was measured including: total cholesterol (TC), high-density lipoprotein (HDL),triglycerides (TG), low-density lipoprotein (LDL), very-low density lipoprotein (VLDL) and the LDL:HDL was calculated. The NLR and PLR were recorded. Results. In RA, NLR, PLR and HDL were significantly higher (p<0.0001, p=0.001, p=0.01). The disease activity score (DAS28) was significantly associated with dyslipidemia (p=0.02) and correlated inversely with NLR (r=-0.3, p=0.02). NLR and PLR correlated significantly with TG (p=0.02, p=0.03) respectively. In SLE, NLR, PLR and TG were significantly higher (p<0.0001, p<0.0001, p<0.001). The SLE disease activity index (SLEDAI) was significantly related to dyslipidemia (p=0.01) and NLR (p=0.005).PLR correlated inversely with the damage index (r=-0.2, p=0.01). SLEDAI correlated significantly with TG, (r=0.4, p<0.0001) and LDL: HDL (r=0.4, p<0.0001) and inversely with HDL(r=-0.4, p<0.0001). In SSc, NLR and PLR were significantly higher (p<0.0001, p=0.03). HDL correlated inversely with modified Rodnan skin score (mRss) (r=-0.3, p=0.04). In axSpA, NLR, PLR and lipid profile were similar to controls. In vasculitis, HDL was significantly higher (p=0.02) and TG correlated inversely with vasculitis damage index (VDI) (r=-0.5, p=0.03). In BD, PLR correlated significantly with the Arabic BD current activity form (Ar-BDCAF) (r=0.9, p=0.003). NLR correlated significantly with TC (r=0.4,p=0.03) and PLR inversely with TG(r=-0.5, p=0.04). NLR, PLR and ESR were valuable predictors of disease activity in RA, SLE, SSc and vasculitis. On comparing the different rheumatic diseases, NLR and TG were significantly higher in SLE (p<0.0001, p=0.002) and PLR in vasculitis (p=0.004). Conclusion. Dyslipidemia is frequently associated with the rheumatic diseases. NLR and PLR are feasible markers with a promising role in evaluation of their disease activities

Silica fume concrete in hot and temperate environments

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Improved 2D Discrete Hyperchaos Mapping with Complex Behaviour and Algebraic Structure for Strong S-Boxes Generation

This paper proposes to present a novel method of generating cryptographic dynamic substitution-boxes, which makes use of the combined effect of discrete hyperchaos mapping and algebraic group theory. Firstly, an improved 2D hyperchaotic map is proposed, which consists of better dynamical behaviour in terms of large Lyapunov exponents, excellent bifurcation, phase attractor, high entropy, and unpredictability. Secondly, a hyperchaotic key-dependent substitution-box generation process is designed, which is based on the bijectivity-preserving effect of multiplication with permutation matrix to obtain satisfactory configuration of substitution-box matrix over the enormously large problem space of 256!. Lastly, the security strength of obtained S-box is further elevated through the action of proposed algebraic group structure. The standard set of performance parameters such as nonlinearity, strict avalanche criterion, bits independent criterion, differential uniformity, and linear approximation probability is quantified to assess the security and robustness of proposed S-box. The simulation and comparison results demonstrate the effectiveness of proposed method for the construction of cryptographically sound S-boxes

Comparative study of three methods of esophageal anastomosis in dogs

This study was performed to compare three methods of esophageal anastomosis. Twenty four healthy adult dogs were used in this study. The animals were divided into three groups; each one consisted of 8 animals. In group 1; two layers were used to perform the esophageal anastomosis. The first layer represented simple interrupted suture to close the mucosa with knot inside the lumen, and the second layer represented horizontal mattress interrupted suture to close the other layers of esophagus. While in group 2; one layer of cross interrupted mattress suture was used to close all layers of esophageal wall, and in group 3; one layer of Schmieden's suture was used to close all layers of esophageal wall. The results of clinical, radiological and histopathological studies after 15 and 30 days of surgical operation revealed that most of the animals showed different degrees of difficulty concerning the moderate dysphagia and regurgitation. The radiological study showed significant difference of stenosis. The best results were recorded in the second group where the mean degree of stenosis was 7.69%, however the mean degree of stenosis was 42.80% in the first group, while the mean degree of stenosis in the third groups was 37.81%, through 30 days. The histopathological study of group 2 showed rapid healing of the site of anastomosis, lack of granulation tissue and consequently the less degree of stricture and other complications as compared with groups 1 and 3. The Schmieden's suture was characterized by its standard short time as compared with group 1 and 2, although accompanied by some complications. In conclusion this study revealed that the cross mattress suture used in the second group characterized by faster healing and minimal amount of fibrous tissue formation manifested by decrease in moderate degree of stenosis as compared with the two other suture patterns used in the first and third groups