Testing and analysis of additively manufactured stainless steel corrugated cylindrical shells in compression

Initial geometric imperfections have been identified as the main cause for the large discrepancies between experimental and theoretical buckling loads of thin-walled circular cylindrical shells under axial compression. The extreme sensitivity to imperfections has been previously addressed and mitigated through the introduction of stiffeners; however, sensitivity still remains. Optimized corrugated cylindrical shells are largely insensitive to imperfections and hence exhibit excellent load-bearing capacities, but their complex geometries make their construction difficult and costly using conventional manufacturing techniques. This was overcome in the present study through additive manufacturing (AM). Nine optimized corrugated shells with different diameter-to-thickness ratios, together with one reference circular cylindrical shell, were additively manufactured by means of powder bed fusion (PBF) from austenitic and martensitic precipitation hardening stainless steel. The structural behavior of the AM shells was then investigated experimentally with the testing program comprising tensile coupon tests, measurements of basic geometric properties, and axial compression tests. Numerical analyses were also conducted following completion of the physical experiments. The experimental and numerical results verified the effectiveness of optimized corrugated cylindrical shells in achieving improved local buckling capacity and reduced imperfection sensitivity. Initial recommendations for the structural design of the studied cross-sections are made

Data related to the manufacturing and mechanical performance of 3D-printed metal honeycombs

The data available in this article include 3D mechanical designs used for the computer-aided fabrication of metal honeycombs produced by additive manufacturing and studied in [1]. In addition, the force-displacement data utilized to evaluate the mechanical performance of the metal used in this study are available via the digital image correlation technique. Further, the surface features obtained using 3D scanning microscopy of the fabricated parts are available as raw files and processed data. Finally, the impact test data are presented as high-frame-rate videos showing the time-displacement numerical values. This information has been provided in this data article to complement the related research, serve as a guide for future studies, and ensure the data's repeatability and reliability of the related research paper. The research article [1] investigates the mechanical performance and failure mechanism of additively manufactured metallic honeycombs under various scenarios, from quasi-static to dynamic loading. It also investigates the design optimization of these energy-absorbing hollow structures by comparing hollow structures made of three distinct novel cell designs (triangular, diamond-shaped, and diamond-shaped with curved walls) with traditional honeycombs made of hexagonal cells

Investigating the Effect of Saffron Petal Extract on Antioxidant Activity and Inflammatory Markers in Hypercholesterolemic Rats

Introduction: High-cholesterol diet is one of the major causes of cardiovascular disease leading to the death of millions of people annually. One of the ways to prevent this risk is the use of chemical drugs, but herbal compounds at controlled levels have less adverse effects than chemical compounds. In the present study, we investigated the effect of hydroalcoholic extract of a saffron petal on malondialdehyde (MDA) and superoxide dismutase (SOD) enzymes, inflammatory markers and lipid profile and compared it with lovastatin in hypercholesterolemic rats. Materials and Methods: Thirty adult Wistar rats were randomly divided into 6 equal groups (n = 5). Group 1 (sham) received a normal diet and Group 2 (control) received only a high-cholesterol diet (2). Group 3 to 6 were treated with a high-cholesterol diet (2) in the first 4 weeks and 100, 200, and 300 mg/kg of saffron petal extract and 10 mg/kg of lovastatin, respectively, in the second 4 weeks. At the end of the study, the level of activity of antioxidant enzymes and the level of lipid profile and inflammatory markers were measured. Results: The mean plasma MDA level, SOD enzyme activity of red blood cell, lipid profile and inflammatory markers were significantly increased in the control group (high-cholesterol diet) compared to the sham group (P <0.001). However, these cases in the other groups treated with hydroalcoholic extract of the saffron petal (groups 3, 4 and 5) and lovastatin drug (group 6) showed a significant decrease (minimum significant difference, P <0.05), despite receiving high-cholesterol diet (p<0.05) compared to the control group. Conclusion: The results of this study showed that a non-toxic dose o f saffron petal extract has an effective role in preventing cardiovascular diseases by reducing the risk factors associated with these diseases

Studying the Effect of Hydroalcoholic Extract of Teucrium polium L. Leaves on Antioxidant Activity and Lipid Profile Alterations

Background: Antioxidants are the most important factors preventing oxidative stress and scavenging free radicals. Nowadays, natural antioxidant compounds are highly important in prevention of cardiovascular diseases. In this study, we have investigated the effect of hydroalcoholic extract of Teucrium polium L. leaves (HETPL) on enzymes related to antioxidant activity and lipid profile alterations in rats. Materials and Method: Male Wistar rats were divided into four equal groups for 8 weeks: Experimental groups of 1 and 2, which had a normal diet and high cholesterol diet (2) respectively, and experimental groups of 3 and 4, which were treated with high cholesterol diet (2) with HETPL at doses of 85 and 170 mg/kg, respectively. The levels of malondialdehyde (MDA) and plasma superoxide dismutase (SOD) of red blood cell (RBC) and lipid profile were measured at the beginning and at the end of the study. Results: The levels of SOD in RBC and plasma MDA in the experimental Group 2 had a significant increase compared to the experimental Group 1 (P < 0.001). The level of these two enzymes in the experimental groups of 3 and 4 was significantly lower than the experimental Group 2 (SOD by P < 0.05 and P < 0.001 and MDA by P < 0.01 and P < 0.001, respectively). The mean serum high-density lipoprotein cholesterol level in experimental Groups 1 and 4 at the end of study had no significant alteration compared to the beginning of the study, but in the experimental groups of 2 and 3, a significant decrease was observed at the end of the study than the beginning of the study (P < 0.001 and P < 0.01, respectively). Mean serum levels of triglyceride (TG), cholesterol, and low-density lipoprotein cholesterol (LDL-c) in experimental Groups 2 (LDL-c and cholesterol: P < 0.001 and TG: P < 0.01) and 3 (P < 0.01) significantly increased compared to the beginning of the study. Conclusion: We conclude that T. polium can play an important role in preventing cardiovascular diseases caused by oxidative stress through its antioxidant and hypolipidemic activities

INVESTIGATING THE METHADONE EFFECTS ON AST, ALT AND ALP ENZYMES OF SERUM OF MALE WISTAR RATS

Narcotics abuse and addiction have been turned to a major problem in the communities. Addiction to any type of narcotics is known to be followed by side effects both physically and psychologically. One way to control addiction is the use of another maintenance medication. The current research paper aims at investigating the effect of one such a drug as methadone on the serum levels of Alkaline phosphatase, Alanine aminotransferase, Aspartate aminotransferase enzymes. A total number of 28 male adult Wistar rats were completely haphazardly assigned to four group (n=7): a control group that received an ordinary daily dietary regime and Experimental groups one, two and three that were administered through oral gavage with 5mg/ml, 20mg/ml and 40mg/ml of methadone syrup, respectively, on a daily basis besides the ordinary dietary regime for eight weeks. Blood samples were collected from the animals at the beginning and at the end of the study for the determination of serum levels of alkaline phosphatase, alanine aminotransferase and aspartate aminotransferase enzymes. In the end, the data were analyzed via taking advantage of one-way variance analysis (one-way ANOVA) and TUKEY Test. The serum levels of all three ALT, AST and ALP enzymes were significantly increased in the groups that had been given different doses of methadone (P < 0.001). According to the results obtained herein and the effects that methadone has on the elevation of liver enzymes levels and also due to the fact that this maintenance medication is being increasingly administered on a daily basis for the treatment of addiction to various narcotics, it seems that there is a need for devising better strategies and better planning for the amount and method of methadone use as well as the way this medication has to be distributed within the society

INVESTIGATION THE ANTI-HYPERLIPIDEMIC EFFECTS OF SAFFRON PETALS' OF HYDROALCOHOLIC EXTRACT IN RATS

The use of medicinal herbs has been customary in traditional medicine since very long ago and according to the intolerances exhibited by some of the patients for chemical drugs due to the emergence of side effects, the medicinal herbs can be utilized as alternative treatments through adhering to evidence-based medical principles. The current research paper investigates the effects of saffron petal hydroalcoholic extract on the lipid profiles. Thirty Wistar rats were assigned to six groups: a control group and a sham group that received ordinary dietary regime and high cholesterol (2) dietary regime, respectively, and experimental groups one to four that, besides the high cholesterol dietary regime, were also, correspondingly, treated by 50, 100 and 200 mg/kg of their body weights saffron petal hydroalcoholic extract per day and 10 mg/kg of the body weight lovastatin per day. Blood samples were collected of the animals after eight weeks to determine their serum lipid profiles. SPSS (version16) was employed to perform the analysis. The serum levels of cholesterol, triglyceride and LDL-C were found significantly increased in sham group and experimental group three (high cholesterol dietary regime plus 200 mg/kg of the extract) in contrast to the control group (P<0.001). The significance level was found lower in experimental group 1 (high cholesterol regime plus 50 mg/kg of the extract) (P<0.05, P<0.001 and P<0.05, respectively). The serum levels of these three factors and HDL-c were not found significantly different in experimental groups two and four in comparison to the control group. The results are indicative of the favorable effects of saffron petal hydroalcoholic extract, especially in lower dosages, on the regulation and correction of the serum lipid profile

ANTIHYPERLIPIDEMIC EFFECTS OF HYDROALCOHOLIC LEAF EXTRACT OF TEUCRIUM POLIUM IN HYPERCHOLESTEROLEMIC RATS

Hyperlipidemia is one of the most important factors contributing to the cardiovascular diseases. There are various chemical drugs for regulating the lipid profile level. According to the side effects proved for the chemical drugs, we, in the current research paper, investigate the effect of wall germander (Teucrium polium) hydroalcoholic extract effect on the lipid profile in the hypercholesterolemic rats. Wistar male rats, ranging in weight from 150 g to 180 g, were assigned to four groups (n=5): control group (ordinary diet), sham group (high, 2, cholesterol dietary regime), experimental group one (high, 2, cholesterol dietary regime plus 0.85mg/ml Teucrium polium hydroalcoholic extract) and experimental group two (high, 2, cholesterol dietary regime plus 1.7mg/ml Teucrium polium hydroalcoholic extract). The treatment was run in an eight-week period with the termination of which blood samples were collected from the animals. To determine the lipid profile, commercial diagnostic kits were applied. The results were analyzed by the use of SPSS software, ver. 16. From the week six on, the weights of the rats from the experimental group two (high, 2, cholesterol diet plus 1.7 mg/ml Teucrium polium hydroalcoholic extract) showed a significant decrease (P<0.05) even in comparison to the control group (ordinary diet). The serum level of triglycerides, cholesterol and LDL-c was found significantly decreased in the experimental group two (P<0.001) as compared to Sham group but it did not any significant change in contrast to the control group. In experimental group one (high, 2, cholesterol dietary regime plus 0.85 mg/ml Teucrium polium hydroalcoholic extract), only the cholesterol and TG serum levels were found significantly decreased in respect to the sham group (P<0.05 and P<0.001, respectively). Regarding the lipoprotein amount, a significant increase was documented in the experimental group two, featuring high density cholesterol (HDL-c), in contrast to the sham group (P<0.001). The present study's findings indicated that an appropriate dosage of T. Polium can cause the regulation of lipid profile as well as the weights of the hypercholesterolemic rats. According to the side effects of the chemical drugs similar in their functions to the effect of T. polium, it can be suggested as an antihyperlipidemic drug

The effect of hydroalcoholic extract of Teucrium polium L. on the inflammatory markers and lipid profile in hypercholesterolemic rats

Background: Cardiovascular diseases are among the most common causes of mortality worldwide. Therefore, it is necessary to control the risk factors of these patients. Since the level of inflammatory markers and lipid profiles has increased in cardiovascular diseases and due to the increasing role of plants in the treatment of diseases, the current study aimed to investigate the effect of hydroalcoholic extract of Teucrium polium on inflammatory markers and lipid profile in hypercholesterolemic rats. Materials and methods: A total of 24 adult male Wistar rats were randomly divided into four groups of six each and treated with oral administration for 8 weeks. The control group received normal diet, the sham group received high-cholesterol diet and experimental groups 1 and 2 received high-cholesterol diet in the 8 weeks and doses of 85 and 170 mg/kg, respectively, of the T. polium hydroalcoholic extract (TPHAE) in the second 4 weeks. At the beginning and the end of the study, rats were examined for biochemical parameters. The mean level of variables for each group was presented as mean +/- standard error of mean. Results: The results of this study showed that, after administration of TPHAE, there was a significant decrease in the mean of inflammatory markers in all groups compared to sham group (P<0.001). Also, administration of the extract significantly reduced the serum levels of triglyceride, cholesterol and LDL-cholesterol and significantly increased the serum HDL-cholesterol levels. In addition, the 170 mg/kg dose of TPHAE was the most effective in reducing serum levels of inflammatory and lipid markers. Conclusion: Treatment with TPHAE caused dose-dependent decrease in serum levels of inflammatory markers and lipid profile in hypercholesterolemic rats. Therefore, it can be applied as a natural product for the management of cardiovascular diseases

Fracture risk in patients with type 2 diabetes mellitus and possible risk factors: a systematic review and meta-analysis

Aim: Patients with type 2 diabetes mellitus (T2DM) have an increased risk of bone fractures. A variable increase in fracture risk has been reported depending on skeletal site, diabetes duration, study design, insulin use, and so on. The present meta-analysis aimed to investigate the association between T2DM with fracture risk and possible risk factors. Methods: Different databases including PubMed, Institute for Scientific Information, and Scopus were searched up to May 2016. All epidemiologic studies on the association between T2DM and fracture risk were included. The relevant data obtained from these papers were analyzed by a random effects model and publication bias was assessed by funnel plot. All analyses were done by R software (version 3.2.1) and STATA (version 11.1). Results: Thirty eligible studies were selected for the meta-analysis. We found a statistically significant positive association between T2DM and hip, vertebral, or foot fractures and no association between T2DM and wrist, proximal humerus, or ankle fractures. Overall, T2DM was associated with an increased risk of any fracture (summary relative risk = 1.05, 95 confidence interval: 1.04, 1.06) and increased with age, duration of diabetes, and insulin therapy. Conclusion: Our findings strongly support an association between T2DM and increased risk of overall fracture. These findings emphasize the need for fracture prevention strategies in patients with diabetes

THE EFFECTS OF TEUCRIUM POLIUM L. ON ATHEROSCLEROTIC PLAQUES IN HYPERCHOLESTEROLEMIC IN RATS

Cardiovascular diseases are amongst the most important mortality causes worldwide. Therefore, it is necessary to offer a drug that meanwhile lacking the side effects of the similar chemical medications is capable of reducing the risk factors of such diseases. In the present study, the effect of hydroalcoholic extract taken from the plant Teucrium Polium on the atherosclerotic plaques has been studied herein. In the current research paper, 20 male Wistar rats with mean weights ranging from 150 g to 180 g were randomly divided to four groups: a control group and a sham group that, respectively, received ordinary dietary regimen and high cholesterol (2) nutrition. Experimental groups 1 and 2 that received ordinary dietary regimens plus Teucrium Polium extracts, with dosages equal to 0.85 mg/ml and 1.7 mg/ml, respectively, on a daily basis. After eight weeks of treatment, the rats' aortas were dissected and kept in 10 formalin solution to undergo histological evaluations. The weight results were analyzed in SPSS software by the use of one-way variance analysis (ANOVA). There was not observed any atherogenic lesion in the control group that had received a normal nutrition. In sham group that had received high cholesterol dietary regimen, atheroma plaques were visible. Experimental groups 1&2 that had been treated with extract dosages of 0.85 mg/ml and 1.7 mg/ml, no sign of any atherogenic lesion and plaque formation was observed even with their being fed on a high cholesterol dietary regime. Also, the sham group members' mean weights showed a significant increase in respect to the control group. Experimental group two demonstrated a significant reduction of weight in contrast to the control group. The hydroalcoholic extract of Teucrium Polium was interestingly successful in preventing the atherosclerotic plaques. According to the side effects of the anti-atherosclerotic chemical medications, it seems that the use of traditional medicine and the medicinal herbs can be an appropriate solution to the reduction of cardiovascular diseases