Using continuous wavelet transform of generalized flexibility matrix in damage identification

Generalized flexibility matrix method has recently been introduced for identifying damages with the aim of overcoming some shortcomings of the approaches based on flexibility matrix. Researchers that use flexibility matrix to detect damages in structures face truncation errors ensue from cut off higher-order mode shapes, which are difficult to measure in practice. In this paper, a new procedure is presented to detect the damage site in a beam-type structure, where generalized flexibility matrix in conjunction with continuous wavelet transform (CWT) is utilized. Since flaws and cracks cause changes in flexibility of a system, this characteristic can be used as a damage indicator. Gaussian wavelet transform with four vanishing moments as a signal processing method is implemented to find the irregularity in a vector obtained from generalized flexibility matrix which is considered as a sign of damage. This method does not need to have either prior knowledge about the intact structure or its finite element model. The proposed technique is evaluated by numerical and experimental case studies

Effect of different dietary protein levels and water salinities on biochemical heamolymph parameters of white leg shrimp (Litopenaeus vannamei) juvenile

In this study, biochemical heamolymph parameters indices of the white leg shrimp (Litopenaeus vannamei) with three dietry protein levels (25, 35 and 45%) in the three levels of water salinity(0-3, 12-15 and 32-35 ppt) was studied. For experimental 350 shrimps with the average weight of 5.55±0.18 g and length of 8.81±0.15 cm were distributed randomly in 27 ten tones (length: 600 cm, width: 170 cm and height: 100 cm) concrete tanks. Experimental group were fed to satiation 4 times a day the experimental period. The results showed that at dietary protein levels of 35 and 45% and the water salinity of 32-35 ppt the amount of protein, urea, HDL and LDL increased (p≤ 0/05). Cholesterol and triglycerides levels in treatment with dietry protein level of 45% and the salinity of 32-35 ppt had increased. The glucose level of the plasma changed only by the modification of the protein level and had a revers relation with this variable (p≤ 0/05). However, different levels of protein and salinity had no effect on the amount of hemolymph uric acid. So besed biochemical heamolymph parameters on the results of this study, in dietry protein level 35% and salinity of 32-35 ppt and at least stress in the levels

Alterations in reproductive hormones during heat stress in dairy cattle

In dairy cows inseminated during the hot months of the year, there is a decrease in fertility. Different factors contribute to this situation; the most important are a consequence of increased temperature and humidity that result in a decreased expression of overt estrus and a reduction in appetite and dry matter intake. Heat stress reduces the degree of dominance of the selected follicle and this can be seen as reduced steroidogenic capacity of its theca and granulosa cells and a fall in blood estradiol concentrations. Plasma progesterone levels can be increased or decreased depending on whether the heat stress is acute or chronic, and on the metabolic state of the animal. These endocrine changes reduce follicular activity and alter the ovulatory mechanism, leading to a decrease in oocyte and embryo quality. The uterine environment is also modified, reducing the likelihood of embryo implantation. Systems activated by heat stress can influence reproduction at the hypothalamus, pituitary gland or gonads. However, the major impact is thought to be within the brain or at the pituitary gland. Measurement of plasma concentrations of the gonadotrophins provides a good indication of the effects at these higher levels, since the pulsatile secretion of luteinizing hormone (LH) is a reflection of the secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus. Both the secretion and actions of GnRH are influenced by the feedback actions of gonadal sex steroids and inhibin. Recent studies suggest that the use of gonadotropins to induce follicular development and ovulation can decrease the severity of seasonal postpartum infertility in dairy cows.Key words: Reproductive hormones, dairy cow and heat stress

Quantification of the uterine involution and dimensions, hormonal response and reproductive performance of pyometric and healthy dairy cows treated with Dinoprost

The aim of the present study was to investigate the effects of a PGF2α analogue (Dinoprost) on involution of the puerperal uterus, especially with pyometra during 35 to 45 days postpartum in multiparous high yielding Holstein dairy cows. At days 40 ± 5 postpartum, 1250 cows were ultrasonographically examined. Fifty cows were diagnosed as pyometric. Fifty pyometric and 50 clinically healthy cows were assigned randomly to one of four groups. Groups were: 1.) Pyometric+Dinoprost cows (PD, n = 25 treated with 25 mg of Dinoprost), 2.) Pyometric+Saline cows (PS, n = 25 treated with saline), 3.) Healthy+Dinoprost cows (HD, n = 25 treated with 25 mg of Dinoprost), and 4.) Healthy+Saline cows (HS, n = 25 treated with saline). All treatments were given intramuscularly. Ultrasonography was performed at the time of examination and 7 days later to evaluate changes in uterine diameter. Treatment with Dinoprost significantly reduced gross uterine diameter in PD in comparison to the PS group in the presence or absence (P4 concentrations <1 ng/ml) of an active corpus luteum. Dinoprost treatment did not decrease gross uterine diameter in groups HD and HS. Luminal diameter was significantly smaller in the PD than in the PS group. Pregnancy rate of PD was greater than PS cows (36% vs 20%, respectively). Days to first service (110 d vs. 140 d) and open days (160 d vs. 190 d) were shorter in PD cows than PS cows. It was concluded that injection of 25 mg of Dinoprost to pyometric cows had uterotonic effects in presence or absence of functional corpus luteum. Therefore, this treatment can help uterine involution in puerperal dairy cows affected by pyometra and consequently improved reproductive performance.Keywords: Cattle, Dinoprost, pregnancy rate, pyometra, uterine healt

Heparinized and saline solutions in the maintenance of arterial and central venous catheters after cardiac surgery

Background: Heparinized saline solution is used to prevent occlusion in the arterial catheters and central venous pressure monitoring catheters. Even at low dose, heparin administration can be associated with serious complications. Normal saline solution can maintain patency of arterial catheters and central venous pressure monitoring catheters. Objectives: The current study aimed to compare the efficacy of normal saline with that of heparinized one to maintain patency of arterial and central venous catheters after cardiac surgery. Patients and Methods: In the current randomized controlled trial, 100 patients, with an age range of 18 - 65 years of valve and coronary artery surgery were studied in Rajaie heart center, Tehran, Iran. Patients were randomized to receive either heparinized saline (n = 50) or normal saline flush solutions (n = 50). In the study, arterial catheters and central venous pressure monitoring catheters were daily checked for any signs of occlusion in three postoperative days as primary end-point of the study. Results: According to the information obtained from the study, four (8) arterial catheters in the saline group (P value: 0.135) and three (6) arterial catheters in the heparin group (P value = 0.097) were obstructed. Statistical analysis showed that the incidence of obstruction and changes in all other parameters between the two groups during the three-day follow-up was not significant (all P values > 0.05). Conclusions: It seems that there is no difference in the use of heparinized and normal saline solutions to prevent catheter occlusion of arterial and central venous pressure. © 2015, Iranian Society of Regional Anesthesia and Pain Medicine (ISRAPM)

The effect of combined conventional and modified ultrafiltration on mechanical ventilation and hemodynamic changes in congenital heart surgery

Background: Cardiopulmonary bypass is associated with increased fluid accumulation around the heart which influences pulmonary and cardiac diastolic function. The aim of this study was to compare the effects of modified ultrafiltration (MUF) versus conventional ultrafiltration (CUF) on duration of mechanical ventilation and hemodynamic status in children undergoing congenital heart surgery. Materials and Methods: A randomized clinical trial was conducted on 46 pediatric patients undergoing cardiopulmonary bypass throughout their congenital heart surgery. Arteriovenous MUF plus CUF was performed in 23 patients (intervention group) and sole CUF was performed for other 23 patients (control group). In MUF group, arterial cannula was linked to the filter inlet through the arterial line, and for 10 min, 10 ml/kg/min of blood was filtered and returned via cardioplegia line to the right atrium. Different parameters including hemodynamic variables, length of mechanical ventilation, Intensive Care Unit (ICU) stay, and inotrope requirement were compared between the two groups. Results: At immediate post�MUF phase, there was a statistically significant increase in the mean arterial pressure, systolic blood pressure, and diastolic blood pressure (P < 0.05) only in the study group. Furthermore, there was a significant difference in time of mechanical ventilation (P = 0.004) and ICU stay (P = 0.007) between the two groups. Inotropes including milrinone (P = 0.04), epinephrine (P = 0.001), and dobutamine (P = 0.002) were used significantly less frequently for patients in the intervention than the control group. Conclusion: Administration of MUF following surgery improves hemodynamic status of patients and also significantly decreases the duration of mechanical ventilation and inotrope requirement within 48 h after surgery. � 2016 Journal of Research in Medical Sciences