22 research outputs found

    Assessing the impacts of COVID-19 on activity-travel scheduling: A survey in the greater Toronto area

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    The COVID-19 lockdown provided many individuals an opportunity to explore changes in their daily routines, particularly when considered in combination with an ever-changing Information and Communication Technology (ICT) landscape. These new routines and alternative activities have the potential to be continued in the post-COVID era. Transportation planners must understand how routines vary to effectively estimate activity-travel scheduling. The purpose of this study is to determine the influence of the COVID-19 pandemic lockdown on activity-travel behavior and the adoption of ICT-based alternative options. A special emphasis is placed on predicting the long-term effects of this disturbance on activity-travel scheduling. This study examines the changes in the frequency and mode of completing five of the most repetitious tasks in the daily schedule (working, grocery and non-grocery shopping, preparing/eating meals, and visiting family/friends) during the lockdown and immediately after reopening. We find an increased preference for home meal preparation over online ordering and a reluctance to engage in in-person shopping until a substantial proportion of the population has acquired a vaccination against the virus. Respondents prefer to work from home if they have adequate access to home office materials (e.g., desk, chair, computer monitor). Individuals with children must also consider suitable childcare before considering a return to work

    Effect of Intra-Canal Direct Current Electric Stimulation on Orthodontic Tooth Movement: An Experimental Study in Canines

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    Objectives: The purpose of this study was to evaluate whether intra-canal application of controlled direct electric current (DEC) could accelerate the amount of orthodontic tooth movement (OTM) in young adult mixed breed dogs.Methods: Fourth premolars of both jaws of five young adult mixed breed dogs were divided into two groups of control and experimental groups. Orthodontic force was applied to both groups using an active NiTi push coil spring. Direct electric stimulation (15µA DC) was conducted by intra-canal usage of electric potential (1.5v). The experimental teeth were compared with controls in terms of clinical OTM results measured with an electronic caliper every two weeks (four time intervals). The animals were sacrificed one month (T2) or two months (T4) after initiation; and tissue sections were decalcified for histological evaluation. The data were analyzed using SPSS 16, Shapiro-Wilk test and paired t-test.Results: Measurements revealed a statistically significant increase in OTM at electrically stimulated sites compared to the control sites in just one time interval (T3: after four weeks) (P< 0.05). Histological sections also showed increased osteoblastic and osteoclastic activity at tension and compression sides of the experimental group compared to the control group, respectively at both time intervals (T2 and T4).Conclusion: Direct intra-canal electric current applied by a miniature electric device is effective for increasing the rate and amount of OTM in canine experimental model

    Ameliorative Effect of Vanillic Acid on Serum Bilirubin, Chronotropic and Dromotropic Properties in the Cholestasis-Induced Model Rats

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    Introduction: The liver modulates several important roles, such as metabolism and liver cirrhosis, which have several cardiovascular problems. Due to preservative role of antioxidant agents in cardiovascular disease, consequently, many of them are applied as medicinal plants in traditional medicine. Vanillic acid (VA), as an antioxidant agent, has a principal preservative role on some diseases. In this study, the effect of vanillic acid was examined on heart rate (as chronotropic property), P-R interval (as dromotropic property), and serum bilirubin in cholestasis-induced model rats. Methods: In this study, 32 male Sprague-Dawley rats weighing 200-250 g were allocated into four groups, and each group contained eight rats as follows: Control (normal saline, 1 ml/kg, gavage, daily for 4 weeks), cirrhotic (normal saline, 1 ml/kg, gavage, daily for 4 weeks), vanillic acid (10 mg/kg, gavage, daily for 4 weeks), cirrhotic treated with vanillic acid (10 mg/kg, gavage, daily for 4 weeks). Chronic biliary cirrhosis was induced in cirrhotic groups by four weeks Bile Duct Ligation (BDL). At the first day and four weeks after surgery, the animals were anesthetized, electrocardiograms were recorded (lead II), and chronotropic and dromotropic properties (HR and PR interval) were investigated. At the end of experimental duration, the animals were anesthetized, and blood samples were taken to measure serum bilirubin. The results were analyzed using t-test and one-way ANOVA by SPSS software, version 22. Results: After induced of BDL, the results presented that laboratory parameter (bilirubin) in the cirrhotic group significantly increased compared to the control group. The P-R interval was reduced in the cirrhotic group compared to the control group, and there was no significant difference between heart rate in all groups. Bilirubin were reduced in cirrhotic groups treated with vanillic acid (VA) compared to cirrhotic group and also administration of VA in the cirrhotic treated with VA increased dromotropic property in comparison with the cirrhotic group. Conclusion: According to the results obtained in this study, preventing elevated bilirubin and increase dromotropic property in cirrhotic group taking the VA suggested that the consumption of vanillic acid as an antioxidant can be effective in the prevention of liver diseases

    The effects of olive leaf extract and 28 days forced treadmill exercise on electrocardiographic parameters in rats

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    Background: There is evidence that regular activity can prevent of cardiovascular diseases. There are many reports that exercise and the consumption of olive leaf extract (OLE) have a positive effect on cardiovascular parameters. This study was conducted to compare the effects of exercise and OLE alone and together on electrocardiographic parameters in rats. Materials and Methods: Male Sprague–Dawley rats were randomly divided into six groups (n = 8 rats in each): Control, exercise, OLE (100, 200, and 400 mg/kg, orally for 14 days), and exercise + OLE (200 mg/kg of extract, orally for 14 days). Exercise training in rats was performed using treadmill for 28 days (1 h/day). Electrophysiological parameters including heart rate, PR interval, QT interval, QT corrected (QTc), RR interval, QRS voltage, and duration were obtained from lead II electrocardiogram (ECG) recorded by a PowerLab system. Statistical evaluation was done by one-way analysis of variance followed by Fisher's least significant difference test and P < 0.05 was considered statistically significant. Results: The amounts of QT (P = 0.0009) and QTc interval (P = 0.0004), RR interval (P < 0.0001), QRS duration (P = 0.004), and QRS voltage (P = 0.003) in the exercise group were significantly higher than those of the control group. However, there were no significant differences in PR interval in comparison with the control group. Exercise (P < 0.0001) and OLE (400 mg/kg, P = 0.043) alone and both in combination (P = 0.007) reduced heart rate and increased the amount of QRS voltage (P = 0.003, P = 0.047, and P = 0.046, respectively) and RR interval (P < 0.0001, P = 0.046, and P = 0.0009, respectively). Conclusion: Results of this study indicated that administration of OLE alone and in combination with exercise has negative chronotropic and positive inotropic effects and also it can prevent of prolongation of QT and QTc interval induced by severe exercise

    Therapeutic effects of ellagic acid on memory, hippocampus electrophysiology deficits, and elevated TNF-α level in brain due to experimental traumatic brain injury

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    Objective(s): Cognitive defects such as learning and memory impairment are amongst the most repetitious sequelae after sever and moderate traumatic brain injury (TBI). It was suggested that ellagic acid (EA), an innate phenol product, display neuroprotective properties against oxidative and inflammatory damages after brain injury. The object of the current study was therapeutic properties of EA on blood-brain barrier (BBB) interruption and elevated content of TNF-α in brain tissue followed by neurologic aftereffects, cognitive and brain electrophysiology deficits as outcomes of diffuse TBI in rat. Materials and Methods: TBI was induced by a 200 g weight falling by a 2-m height through a free-falling tube onto the head of anesthetized rat. TBI rats treated immediately after trauma with EA             (100 mg/kg, IP) once every 8 hr until 48 hr later. Neurologic outcomes, passive avoidance task (PAT), hippocampal long-term potentiation (LTP), BBB permeability and content of TNF-α in brain tissue were evaluated. Results: TBI induced significant impairments in neurological score, BBB function, PAT and hippocampal LTP in TBI+Veh group in compare with Sham+Veh (

    Effect of vanillic acid on ischemia-reperfusion of isolated rat heart: Hemodynamic parameters and infarct size assays

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    641-646<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" letter-spacing:-.1pt;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="" lang="EN-GB">Vanillic acid is an oxidized form of vanillin produced during the conversion of vanillin to ferulic acid and has free radical scavenging, antioxidant and anti-inflammatory properties. In this study, we investigated the effects of vanillic acid on hemodynamic parameters and infarct size in ischemia-reperfusion of isolated rat heart. Adult male Sprague Dawley rats were randomly divided into control and treatment groups (n=10). The treatment groups were administered vanillic acid 5, 10 and 20 mg/kg orally for 10 days, then the hearts isolated and were exposed to 30 min ischemia and 1 h reperfusion, using langendorff apparatus. The effects of vanillic acid, on left ventricular developed pressure (LVDP), LV end diastolic pressure (LVEDP), LV pressure (LVP), peak rate of rise and fall of LVP (±dp/dt), coronary flow (CF), rate pressure product (RPP) and infarct size were examined. Rats administered with vanillic acid (10 and 20 mg/kg), displayed significantly improved recovery of LVEDP, RPP, LVDP, LVP and ± dp/dt as compared to control group. There was also significant beneficial effect of these two doses to reduce infarct size. Our results suggest that vanillic acid can effectively improve ventricular function and reduce infarct size in ischemia-reperfusion of isolated rat heart.</span

    The effects of gallic acid on pain and memory following transient global ischemia/reperfusion in Wistar rats

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    Objective: It is generally agreed that most of the phenomena observed during brain ischemia and reperfusion can be explained by the damage to membrane structure. Oxidative stress is resulted in an imbalance between high consumption of oxygen and low levels of endogenous antioxidants. It is known that gallic acid (GA) is a strong antioxidant. The present study was carried out to evaluate the effect of GA on ischemia/reperfusion (I/R)-induced brain injury in rats.  Materials and Methods: Wistar adult male rats weighing 200–250 g were divided into six groups as sham operated (Sh), ischemia/reperfusion (I/R) received normal saline (I+Veh), I/R groups treated with gallic acid (I+GA, 50, 100, or 200 mg/kg, orally, respectively), or with 100 mg /kg phenytoin (I+Phen). The global cerebral I/R injury was induced by occluding bilateral common carotid arteries (BCCA) for 20 min, followed by 5 days reperfusion in adult male rats. Results: It was found that administration of 100 mg/kg GA for 5 days before and 5 days after I/R induction reversed gait performance, sensorimotor disorders (

    Effect of crocin on nitric oxide synthase expression in post-ischemic isolated rat heart

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    Objective: Oxidative stress damages cells and brings about the pathogenesis of ischemia/reperfusion injury. This study was carried out to investigate the preconditioning and cardio protective potential effects of crocin and vitamin E by the eNOS and iNOS express gene in ischemia/reperfusion in rats. Material & Methods: Male rats were divided into seven groups, namely: sham, control group and experimental groups treated with crocin(10, 20 and 40 mg/kg), vitamin E (100 mg/kg) and combination of crocin (40 mg/kg) with vitamin E (100 mg/kg) that were gavaged The heart was removed and relocated to a Langendorff apparatus and subjected to global ischemia and then the left ventricular end diastolic pressure (LVEDP) were measured as a hemodynamic parameter. Total RNA was extracted from heart frozen tissues. RT-PCR technique was performed by specific primers designed for nitric oxide gene and the results were assessed by agarose gel electrophoresis. Results: Results after ischemia and reperfusion showed that crocin 40 mg/kg produced a significant improvement of LVEDP as a mechanical function (
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