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In this paper, a numerical solution of the Navier-Stokes equations is considered using the Jameson method in the transonic flow regime over three air gun pellets. The considered pellets have the same caliber of 4.5 mm, but different nose shapes; they are axisymmetric projectiles of three basic types, namely wadcutter, sharp pointed, and roundnose. After these pellets have been modeled geometrically, the Navier-Stokes equations as the governing equations of the flow field around the pellets are solved. Computed aerodynamic results have been used in order to analyze the trajectories of the projectiles,dynamically. The variation of the drag coefficient by Mach number of the free stream flow,which is a key point for the dynamic analysis of the projectile motion, has been obtained. The dynamic analysis of the motion of pellets precisely describes the trajectory and how the velocity of the pellet and the altitude slump with time and location. Relying on these analyses, from both aerodynamic and dynamic points of view, the round-nose pellet in a variable range of Mach numbers shows the best aerodynamic and dynamic behaviors in comparison with other pellets. [ABSTRACT FROM AUTHOR]

In the present study, we evaluated a pretreatment with four LED light sources (red, blue, red + blue, and white) in two genotypes (green and purple) of basil on the growth parameters, stress oxidative markers, non-enzymatic antioxidants, osmoprotectant compounds, ion content, and polyphenolic profile under both control and salinity stress conditions. The results indicated that 150 mM of NaCl decreased biomass, RWC, and K + /Na + ratio but increased the content of proline and antioxidant capacity in the leaves of both genotypes of basil grown under GH (greenhouse) conditions. The results suggested that RB LED-exposed plants in the green genotype and R LED-exposed plants in the purple genotype improved accumulation of shoot biomass, K + /Na + ratio, proline and soluble sugars, glutathione and ascorbate, polyphenolic profile, and thioredoxin reductase activity in the leaves of basil under both control and salinity stress conditions. NaCl stress (150 mM) increased oxidative markers, which are responsible for disturbance of routine functions of various plant cellular modules. LED light pretreatments diminished these markers under both control and salinity stress conditions. It could be concluded that intensification of non-enzymatic antioxidant systems during light-mediated priming can diminish the deleterious effects of ROS induced by NaCl stress (150 mM) through preventing the lipid peroxidation, scavenging cytotoxic H 2 O 2 , and enhancement of antioxidant potentials. Therefore, usage of LED lighting systems as a pretreatment or to supplement natural photoperiods under both control and salinity stress conditions may be advantageous for increasing biomass and phytochemical accumulation in basil., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Curved microchannels allow controllable microparticle focusing, but a full understanding of particle behavior has been limited-even for simple rectangular and trapezoidal shapes. At present, most microfluidic particle separation literature is dedicated to adding "internal" complexity (via sheath flow or obstructions) to relatively simple cross-sectional channel shapes. We propose that, with sufficient understanding of particle behavior, an equally viable pathway for microparticle focusing could utilize complex "external" cross-sectional shapes. By investigating three novel, complex spiral microchannels, we have found that it is possible to passively focus (6, 10, and 13  μ m) microparticles in the middle of a convex channel. Also, we found that in concave and jagged channel designs, it is possible to create multiple, tight focusing bands. In addition to these performance benefits, we report an "additive rule" herein, which states that complex channels can be considered as multiple, independent, simple cross-sectional shapes. We show with experimental and numerical analysis that this new additive rule can accurately predict particle behavior in complex cross-sectional shaped channels and that it can help to extract general inertial focusing tendencies for suspended particles in curved channels. Overall, this work provides simple, yet reliable, guidelines for the design of advanced curved microchannel cross sections.

Inertial microfluidics represents a powerful new tool for accurately positioning cells and microparticles within fluids for a variety of biomedical, clinical, and industrial applications. In spite of enormous advancements in the science and design of these devices, particularly in curved microfluidic channels, contradictory experimental results have confounded researchers and limited progress. Thus, at present, a complete theory which describes the underlying physics is lacking. We propose that this bottleneck is due to one simple mistaken assumption-the locations of inflection points of the Dean velocity profile in curved microchannels are not fixed, but can actually shift with the flow rate. Herein, we propose that the dynamic distance ( δ ) between the real equilibrium positions and their nearest inflection points can clearly explain several (previously) unexplained phenomena in inertial microfluidic systems. More interestingly, we found that this parameter, δ , is a function of several geometric and operational parameters, all of which are investigated (in detail) here with a series of experiments and simulations of different spiral microchannels. This key piece of understanding is expected to open the door for researchers to develop new and more effective inertial microfluidic designs.

Microalgae represent the most promising new source of biomass for the world's growing demands. However, the biomass productivity and quality is significantly decreased by the presence of bacteria or other invading microalgae species in the cultures. We therefore report a low-cost spiral-microchannel that can effectively separate and purify Tetraselmis suecica (lipid-rich microalgae) cultures from Phaeodactylum tricornutum (invasive diatom). Fluorescent polystyrene-microbeads of 6 μm and 10 μm diameters were first used as surrogate particles to optimize the microchannel design by mimicking the microalgae cell behaviour. Using the optimum flowrate, up to 95% of the P. tricornutum cells were separated from the culture without affecting the cell viability. This study shows, for the first time, the potential of inertial microfluidics to sort microalgae species with minimal size difference. Additionally, this approach can also be applied as a pre-sorting technique for water quality analysis., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this study, we report the use of a high-throughput microfluidic spiral chip to screen out eggs from a mixed age nematode population, which can subsequently be cultured to a desired developmental stage. For the sorting of a mixture containing three different developmental stages, eggs, L1 and L4, we utilized a microfluidic spiral chip with a trapezoidal channel to obtain a sorting efficiency of above 97% and a sample purity (SP) of above 80% for eggs at different flow rates up to 10 mL min -1 . The result demonstrated a cost-effective, simple, and highly efficient method for synchronizing C. elegans at a high throughput (∼4200 organisms per min at 6 mL min -1 ), while eliminating challenges such as clogging and non-reusability of membrane-based filtration. Due to its simplicity, our method can be easily adopted in the C. elegans research community.

The separation of micro-sized particles in a continuous flow is crucial part of many industrial processes, from biopharmaceutical manufacturing to water treatment. Conventional separation techniques such as centrifugation and membrane filtration are largely limited by factors such as clogging, processing time and operation efficiency. Microfluidic based techniques have been gaining great attention in recent years as efficient and powerful approaches for particle-liquid separation. Yet the production of such systems using standard micro-fabrication techniques is proven to be tedious, costly and have cumbersome user interfaces, which all render commercialization difficult. Here, we demonstrate the design, fabrication and evaluation based on CFD simulation as well as experimentation of 3D-printed miniaturized hydrocyclones with smaller cut-size for high-throughput particle/cell sorting. The characteristics of the mini-cyclones were numerically investigated using computational fluid dynamics (CFD) techniques previously revealing that reduction in the size of the cyclone results in smaller cut-size of the particles. To showcase its utility, high-throughput algae harvesting from the medium with low energy input is demonstrated for the marine microalgae Tetraselmis suecica. Final microalgal biomass concentration was increased by 7.13 times in 11 minutes of operation time using our designed hydrocyclone (HC-1). We expect that this elegant approach can surmount the shortcomings of other microfluidic technologies such as clogging, low-throughput, cost and difficulty in operation. By moving away from production of planar microfluidic systems using conventional microfabrication techniques and embracing 3D-printing technology for construction of discrete elements, we envision 3D-printed mini-cyclones can be part of a library of standardized active and passive microfluidic components, suitable for particle-liquid separation.

Background: Congenital hypothyroidism (CH), as one of the most common congenital endocrine disorders, may be significantly associated with congenital malformations. This study investigates urogenital abnormalities in children with primary CH (PCH). Methods: This case-control study was conducted on 200 children aged three months to 1 year, referred to Amir-Kabir Hospital, Arak, Iran. One hundred children with PCH, as the case group, and 100 healthy children, as the control group, were selected using convenient sampling. For all children, demographic data checklists were filled, and physical examination, abdomen and pelvic ultrasound and other diagnostic measures (if necessary) were performed to evaluate the congenital urogenital abnormalities including anomalies of the penis and urethra, and disorders and anomalies of the scrotal contents. Results: Among 92 (100%) urogenital anomalies diagnosed, highest frequencies with 37 (40.2%), 26(28.2%) and 9 (9.7%) cases including hypospadias, Cryptorchidism, and hydrocele, respectively. The frequency of urogenital abnormalities among 32 children with PCH, with 52 cases (56.5%) was significantly higher than the frequency of abnormalities among the 21 children in the control group, with 40 cases (43.4%). (OR=2.04; 95%CI: 1.1-3.6; p=0.014). Conclusion: Our study demonstrated that PCH is significantly associated with the congenital urogenital abnormalities. However, due to the lack of evidence in this area, further studies are recommended to determine the necessity of conducting screening programs for abnormalities of the urogenital system in children with CH at birth.

Mixing fluid samples or reactants is a paramount function in the fields of micro total analysis system (μTAS) and microchemical processing. However, rapid and efficient fluid mixing is difficult to achieve inside microchannels because of the difficulty of diffusive mass transfer in the laminar regime of the typical microfluidic flows. It has been well recorded that the mixing efficiency can be boosted by migrating from two-dimensional (2D) to three-dimensional (3D) geometries. Although several 3D chaotic mixers have been designed, most of them offer a high mixing efficiency only in a very limited range of Reynolds numbers ( Re ). In this work, we developed a 3D fine-threaded lemniscate-shaped micromixer whose maximum numerical and empirical efficiency is around 97% and 93%, respectively, and maintains its high performance (i.e., >90%) over a wide range of 1 <  Re  < 1000 which meets the requirements of both the μTAS and microchemical process applications. The 3D micromixer was designed based on two distinct mixing strategies, namely, the inducing of chaotic advection by the presence of Dean flow and diffusive mixing through thread-like grooves around the curved body of the mixers. First, a set of numerical simulations was performed to study the physics of the flow and to determine the essential geometrical parameters of the mixers. Second, a simple and cost-effective method was exploited to fabricate the convoluted structure of the micromixers through the removal of a 3D-printed wax structure from a block of cured polydimethylsiloxane. Finally, the fabricated mixers with different threads were tested using a fluorescent microscope demonstrating a good agreement with the results of the numerical simulation. We envisage that the strategy used in this work would expand the scope of the micromixer technology by broadening the range of efficient working flow rate and providing an easy way to the fabrication of 3D convoluted microstructures.

Blood and blood products are critical components of health care. Blood components perform distinct functions in the human body and thus the ability to efficiently fractionate blood into its individual components (i.e., plasma and cellular components) is of utmost importance for therapeutic and diagnostic purposes. Although conventional approaches like centrifugation and membrane filtration for blood processing have been successful in generating relatively pure fractions, they are largely limited by factors such as the required blood sample volume, component purity, clogging, processing time and operation efficiency. In this work, we developed a high-throughput inertial microfluidic system for cell focusing and blood plasma separation from small to large volume blood samples (1-100 mL). Initially, polystyrene beads and blood cells were used to investigate the inertial focusing performance of a single slanted spiral microchannel as a function of particle size, flow rate, and blood cell concentration. Afterwards, blood plasma separation was conducted using an optimised spiral microchannel with relatively large dimensions. It was found that the reject ratio of the slanted spiral channel is close to 100% for blood samples with haematocrit (HCT) values of 0.5% and 1% under an optimal flow rate of 1.5 mL min(-1). Finally, through a unique multiplexing approach, we built a high-throughput system consisting of 16 spiral channels connected together, which can process diluted samples with a total flow rate as high as 24 mL min(-1). The proposed multiplexed system can surmount the shortcomings of previously reported microfluidic systems for plasma separation and cell sorting in terms of throughput, yield and operation efficiency.

Background: Chronic kidney disease (CKD) is a common medical condition among children and obsessive-compulsive disorder (OCD) is a frequent, chronic, costly, and disabling disorder among them., Objectives: The aim of this study was to investigate obsessive-compulsive disorder (OCD) in children with early stages of CKD, and to compare it with the occurrence of OCD in healthy children., Patients and Methods: In this case-control study, we evaluated 160 children aged 7 to 17 years old who were visited in the pediatric clinics of Amir-Kabir hospital, Arak, Iran. The control group consisted of 80 healthy children and the case group included 80 children with Stage 1 to 3 CKD. The ages and sex of the children in the two groups were matched. OCD in children was evaluated using the obsessive compulsive inventory-child version (OCI-CV)., Results: The mean scores of doubting/checking (case: 3.52 ± 2.54, control: 2.5 ± 2.32, P = 0.007) and ordering (case: 2.59 ± 1.81, control: 1.5 ± 2.56, P = 0.005) in the children with CKD was significantly higher than in the healthy ones. Moreover, the mean total scores for the OCI-CV of the children with CKD at 15.32 ± 7.69 was significantly higher than the scores of the healthy ones at 11.12 ± 2.54 (P = 0.021). There was a significant correlation between the CKD duration and doubting/checking (P = 0.004, correlation coefficient (CC): 0.4), obsessing (P = 0.06, CC: 0.02), washing (P = 0.031, CC: 0.8), ordering (P = 0.001, CC: 0.2), and the total scores of the OCI-CV questionnaire (P = 0.04, CC: 0.4)., Conclusions: The risk of OCD in children with CKD is significantly higher than that in healthy children. Although the results seem to suggest that psychiatric intervention can be helpful in treating OCD in children with CKD, further investigation into the medical condition is required so as to obtain more definitive conclusions.

Background: Nephrolithiasis in children is associated with a high rate of complications and recurrence., Objectives: Since some evidences reported that zinc has an important place amongst inhibitors of crystallization and crystal growth, we decided to assess the effectiveness of oral zinc sulfate as adjuvant treatment in children with nephrolithiasis., Patients and Methods: This was a randomized, double-blind, placebo-controlled clinical trial. 102 children in the age range 1 month to 11 years with first nephrolithiasis were recruited. Patients were randomly divided into two equal groups (intervention and control groups). Intervention group received conservative measures for stones and 1 mg/kg/day (maximum 20 mg/day) oral zinc sulfate syrup for 3 months. Control group received placebo in addition to conservative measures, also for 3 months. Patients were followed up by ultrasonography for 9 months, in 5 steps (at the end of 1st, 2nd, 3rd, 6th and 9th month after treatment) assessing size and number of stones in the kidneys., Results: Only at the end of the first month, the average number (intervention: 1.15 ± 3.78, control: 1.3 ± 2.84) (P = 0.001) and size (cm) (intervention: 0.51 ± 1.76, control: 0.62 ± 1.39) (P = 0.001) of stones was significantly lower in the intervention group, and in other points there was no significant therapeutic efficacy in oral zinc adjuvant treatment compared to conservative treatment alone. Also, during the 9-month follow-up, the number and size of stones in both groups decreased significantly (both: P < 0.0001) in a way that the decrease in the intervention group showed no difference with the control group., Conclusions: Adjuvant treatment with zinc is not more effective than consecutive treatment in children with nephrolithiasis. However, further studies are recommended due to the lack of clinical evidence in this field.

Introduction: Congenital hypothyroidism (CH) may be significantly associated with congenital malformations. However, there is little evidence on the relationship between renal and urinary tract anomalies and CH., Objectives: The aim of this study was to compare the renal and upper urinary tract anomalies in children with and without primary CH (PCH)., Patients and Methods: This case-control study was conducted on 200 children aged 3 months to 1 year, referring to Amir-Kabir hospital, Arak, Iran. One hundred children with PCH, as the case group, and 100 children without CH, as the control group, were selected. For all children, ultrasonography and other diagnostic measures (if necessary) were performed to evaluate renal and upper urinary tract anomalies (ureter and bladder)., Results: The frequency of renal and upper urinary tract anomalies among 43 children with primary CH, with 83 cases (72.8%), was significantly higher than the frequency of anomalies among the 19 children in the control group, with 31 cases (27.1%) (OR = 3; CI 95%: 1.6-5.4; P = 0.001). Among the anomalies studied, only the differences in frequency of uretero-pelvic junction obstruction (UPJO) (OR = 6; CI 95%: 1.3-28; P = 0.018) and hydronephrosis (OR = 22; CI 95%: 5-95; P = 0.001) was significant between the two groups., Conclusion: Our study demonstrated that PCH is significantly associated with the frequency of congenital anomalies of the kidneys and upper urinary tracts. However, further studies are recommended to determine the necessity of conducting screening programs for anomalies of the kidneys and urinary tract in children with CH at birth.

Background: Idiopathic hypercalciuria (IHC) can be one of the causes of nocturnal enuresis (NE) and hydrochlorothiazide (HCT) ameliorates hypercalciuria., Objectives: The aim of this study was to assess the therapeutic efficacy of HCT in boys with primary monosymptomatic NE (PMNE)., Patients and Methods: This study was a randomized double-blind placebo-controlled clinical trial. A hundred boys with PMNE and IHC were randomly assigned into two groups of experimental (treated with HCT 1 mg/kg/day) and control and all patients were followed for 4 months for the number of wet-night episodes., Results: The mean numbers of wet-night episodes in the first (intervention: 8.34 ± 8.54, control: 9.1 ± 9.3, P = 0.3), second (7.1 ± 7.3, 7.9 ± 8.1, P = 0.4), third (7.8 ± 8, 7.9 ± 8.1, P = 0.1) and fourth (4.9 ± 5.1, 5.9 ± 6, P = 0.3) months were not significantly different between the two groups. However, the decrease in the average wet-night episodes during the 4 months of treatment in the intervention group (P = 0.019) unlike the control group. Not more significant compared to control group (P = 0.191). All patients who were treated by HCT became normocalciuric. However, in 21 patients the dose was increased to 2 mg/kg/day., Conclusions: Single daily dose of HCT is a safe and effective therapeutic option in the treatment of PMNE in children with IHC.

Objective: To determine the diagnostic value of blood cells surface markers in patients with acute appendicitis., Methods: In this cross-sectional study, 71 patients who underwent appendectomy following a diagnosis of appendicitis were recruited during a one-year period. The patients were divided into two groups: patients with histopathologically confirmed acute appendicitis and subjects with normal appendix. Blood cell surface markers of all patients were measured. Univariate and multivariate analytical methods were applied to identify the most useful markers. Receiver operating characteristics (ROC) curves were also used to find the best cut-off point, sensitivity, and specificity., Results: Overall we included 71 patients with mean age of 22.6±10.7 years. Of the 71 cases, 45 (63.4%) had acute appendicitis while 26 (36.6%) were normal. There was no significant difference between two study groups regarding the age (p=0.151) and sex (p=0.142). The initial WBC count was significantly higher in those with acute appendicitis (p=0.033). Maximum and minimum area under the ROC curve in univariate analysis was reported for CD3/RA (0.71) and CD38 (0.533), respectively. Multivariate regression models revealed the percentage of accurate diagnoses based on the combination of γ/δ TCR, CD3/RO, and CD3/RA markers to be 74.65%. Maximum area under the ROC curve (0.79) was also obtained for the same combination., Conclusion: the best blood cell surface markers in the prediction of acute appendicitis were HLA-DR+CD19, a/β TCR, and CD3/RA. The simultaneous use of γ/δ TCR, CD3/RA, and CD3/RO showed the highest diagnostic value in acute appendicitis.

Background: Attention-deficit/hyperactivity disorder (ADHD) is the most common childhood psychiatric disorder. This disorder is more prevalent in some chronic disease., Objectives: The aim of this study was to investigate ADHD in children with end-stage renal disease (ESRD) undergoing continuous ambulatory peritoneal dialysis (CAPD) and to compare the results with those of healthy children., Patients and Methods: This case-control study was conducted for six months (December 22, 2013 to June 21, 2014) on five to 16-year-old children, visiting the Pediatric Dialysis Unit of Amirkabir Hospital, Arak, Iran, and Taleghani Hospital, Kermanshah, Iran. A total of 100 children with ESRD who had undergone CAPD for at least six months and 100 healthy children were included in this study as case and control groups, respectively. ADHD was diagnosed by Conner's Parent Rating Scale-48 (CPRS-48) and DSM-IV-TR criteria, and was confirmed through consultation by psychologist. Data were analyzed by Binomial test in SPSS 18., Results: The ADHD inattentive type was observed in 16 cases (16%) with CAPD and five controls (5%) (P = 0.01). Moreover, ADHD hyperactive-impulsive type was observed in 27 cases (27%) with CAPD and seven controls (9%) (P = 0.002). Despite these significant differences, no children were diagnosed with ADHD combined type among all subjects., Conclusions: Inattentive type and hyperactive-impulsive type of ADHD are more prevalent in children with ESRD undergoing CAPD. Therefore screening methods for ADHD is necessary in these patients.

Introduction: Vitamin E is a fat-soluble vitamin that functions as an antioxidant. The aim of this study was to investigate the effects of vitamins E supplementation in combination with antibiotics for the treatment of girls with acute pyelonephritis., Materials and Methods: This double-blinded randomized controlled trial was conducted on 152 girls aged 5 to 12 years with a first acute pyelonephritis episode based on technetium Tc 99m dimercaptosuccinic acid (99mTc-DMSA). They were randomized to receive a 14-day treatment with only antibiotics (control group; n = 76) and 14-day treatment with supplements of vitamin E (intervention group; n = 76) in addition to the antibiotics. Patients' clinical symptoms were monitored for 14 days and urine culture was performed 3 to 4 days and 7 to 10 days after the start of the treatment and its completion, respectively. All of the girls once underwent DMSA scan 4 to 6 months after the treatment., Results: During the follow-up days, the mean frequency of fever (P = .01), urinary frequency (P = .001), urgency (P = .003), dribbling (P = .001), and urinary incontinence (P = .006) were significantly lower in the intervention group compared to the control group. There was no significant difference in the results of urine culture 3 to 4 days after the start of treatment (P = .16) and 7 to 10 days after its termination (P = .37). There was also no significant difference between the results of DMSA scan 4 to 6 months after the start of treatment (P = .31)., Conclusions: Vitamin E supplementation has a significant effect in ameliorating sign and symptoms of UTI. However, further studies are recommended to confirm these findings.

Background: Simple febrile convulsion is the most common disease of the nervous system in children. There are hypotheses that iron deficiency may affect febrile convulsion and the threshold of neuron excitation., Aims: This study was conducted with the objective of finding the effects of iron deficiency anemia on simple febrile convulsion episodes., Settings and Design: The study was conducted at AmirKabir Hospital of Arak Medical Sciences University, Arak, Iran. This is a case-control study., Materials and Methods: In this study, 382 children who were selected according to our inclusion and exclusion factors, were divided into two groups of case (febrile convulsion) and control (other factors causing fever) by their cause of hospitalization. After fever subsided, 5 ml blood sample was taken from each child and complete blood count and iron profile tests were performed., Statistical Analysis: The results were interpreted using descriptive statistics and independent t-test., Results: The prevalence of anemia in the group with febrile convulsion was significantly less than that in the control group: 22.5% of the children in the group with febrile convulsion and 34% in the control group exhibited anemia (P < 0.001). Moreover, the group with febrile convulsion had significantly higher blood indices, such as Hb, Hct, MCV, MCH, and MCHC, compared to the control group (P < 0.001)., Conclusions: Iron deficiency can prevent febrile convulsion in children and probably increases the threshold of neuron excitation in fever.

Background: According to the reports of the World Health Organization 20% of world population suffer from pain and 33% of them suffer to some extent that they cannot live independently., Methods: This is a cross-sectional study which was conducted in the emergency department (ED) of Valiasr Hospital of Arak, Iran, in order to determine the causes of delay in prescription of analgesics and to construct a model for prediction of circumstances that aggravate oligoanalgesia. Data were collected during a period of 7 days., Results: Totally, 952 patients participated in this study. In order to reduce their pain intensity, 392 patients (42%) were treated. Physicians and nurses recorded the intensity of pain for 66.3% and 41.37% of patients, respectively. The mean (SD) of pain intensity according to visual analogue scale (VAS) was 8.7 (1.5) which reached to 4.4 (2.3) thirty minutes after analgesics prescription. Median and mean (SD) of delay time in injection of analgesics after the physician's order were 60.0 and 45.6 (63.35) minutes, respectively. The linear regression model suggested that when the attending physician was male or intern and patient was from rural areas the delay was longer., Conclusions: We propose further studies about analgesics administration based on medical guidelines in the shortest possible time and also to train physicians and nurses about pain assessment methods and analgesic prescription.

Background: Misconceptions are mental models of phenomena that are at variance with accepted scientific models of these phenomena., Aim: The goal of this study was to investigate the prevalence of some misconceptions among students about cardiovascular physiology and to evaluate the effectiveness of cardiovascular physiology teaching in alleviating these misconceptions., Method: A descriptive-analytic survey was undertaken with 348 undergraduates from the fields of medicine, nursing, and biology. Students were divided into two groups on the basis of whether they had passed or not taken the cardiovascular physiology course. The students were asked to answer four questions relating to cardiovascular. Descriptive statistic analysis and two-tailed comparison of the proportions was used to analyze their answers., Results: The prevalence of misconceptions about the left ventricular output versus the right ventricular output ranged from 80% to 98%. The misconception about pulse velocity compared with blood velocity in the vessels was 74% to 89%. Between 95% and 99% of answers to the effect of increased resistance on blood flow were incorrect in all groups. Between 69% and 73% of the students had trouble answering the question on parallel resistance and the effect of the removal of one limb on total peripheral resistance. For most of the questions, university lectures had no effect on alleviating these misconceptions., Conclusions: These results indicate that there is a high prevalence of misconceptions among students about at least four cardiovascular concepts associated with cardiovascular physiology and that teaching has failed to alleviate these misconceptions.