A Mathematical Simulation of the Ureter: Effects of the Model Parameters on Ureteral Pressure/Flow Relations

Ureteral peristaltic mechanism facilitates urine transport from the kidney to the bladder. Numerical analysis of the peristaltic flow in the ureter aims to further our understanding of the reflux phenomenon and other ureteral abnormalities. Fluid-structure interaction (FSI) plays an important role in accuracy of this approach and the arbitrary Lagrangian–Eulerian (ALE) formulation is a strong method to analyze the coupled fluid-structure interaction between the compliant wall and the surrounding fluid. This formulation, however, was not used in previous studies of peristalsis in living organisms. In the present investigation, a numerical simulation is introduced and solved through ALE formulation to perform the ureteral flow and stress analysis. The incompressible Navier–Stokes equations are used as the governing equations for the fluid, and a linear elastic model is utilized for the compliant wall. The wall stimulation is modeled by nonlinear contact analysis using a rigid contact surface since an appropriate model for simulation of ureteral peristalsis needs to contain cell-to-cell wall stimulation. In contrast to previous studies, the wall displacements are not predetermined in the presented model of this finite-length compliant tube, neither the peristalsis needs to be periodic. Moreover, the temporal changes of ureteral wall intraluminal shear stress during peristalsis are included in our study. Iterative computing of two-way coupling is used to solve the governing equations. Two phases of nonperistaltic and peristaltic transport of urine in the ureter are discussed. Results are obtained following an analysis of the effects of the ureteral wall compliance, the pressure difference between the ureteral inlet and outlet, the maximum height of the contraction wave, the contraction wave velocity, and the number of contraction waves on the ureteral outlet flow. The results indicate that the proximal part of the ureter is prone to a higher shear stress during peristalsis compared with its middle and distal parts. It is also shown that the peristalsis is more efficient as the maximum height of the contraction wave increases. Finally, it is concluded that improper function of ureteropelvic junction results in the passage of part of urine back flow even in the case of slow start-up of the peristaltic contraction wave

Comparison of serum zinc in children younger than 5 years old with febrile convulsion, children with seizures without fever and normal children

Background: Febrile seizures are the most common seizure disorder in children and have a good prognosis. Many theories about the role of neurotransmitters and trace elements in serum and cerebrospinal fluid are introduced as the pathogenesis of febrile seizures. Among these elements, the element can be noted. The purpose of this study to comparison of serum zinc in children younger than 5 years old with febrile convulsion, children with seizures without febrile and normal children.Methods: In this study, 180 children were studied in three groups. 60 children with seizures without fever and 60 children with febrile convulsions admitted to hospital and 60 healthy children without a history of seizures. Afzalipour who were referred to health centers in the city of Kerman. Serum zinc levels in all three groups were measured by atomic absorption spectrophotometry.Results: The mean serum zinc levels in children with febrile seizures in this investigation was 48.4 µg/dl, compared with the other two tense children without fever (64.61 µg/dl) and healthy children (67.33 µg/dl) was significantly lower.Conclusion:Results of this study showed reduced serum zinc levels during febrile seizure. The need for continued research on surface tension in febrile children over several months is recommended.

Yeast Enriched with Selenium: A Promising Source of Selenomethionine and Seleno-Proteins

Organic selenium compound such as selenomethionine plays a significant function in response to oxidative stress. Currently Saccharomyces cerevisiae is one of the best organisms that has ability to accumulate selenomethionine and selenium biotransformation. Addition of mineral selenium to medium culture is a very common practice in order to produce the selenomethionine and Seleno-proteins. Due to the toxicity of selenium for yeasts, selenium tolerant yeast isolation procedures are required. The aim of this investigation was to separate indigenous selenium tolerant S.cerevisiae strains which will not be affected by high selenium concentrations and are able to produce high levels of selenomethionine. In this study, 85 samples were collected from fermentative fruit. Screening was carried out in order to select high yeast cell density and also high selenomethionine accumulation. After confirming yeast strains, selected strains were cultured at a concentration of 25 mg/L sodium selenite and selenomethionine content was measured after 48 hours. The S18 isolate showed had maximum biomass production and selenomethionine accumulation (2655 ppm) and (3.73 g/L) compared to the other isolates.Highlights Selenomethionine is an important amino acid that has a significant role against oxidative stress.Addition of inorganic selenium to the yeast media culture leads to produce the selenomethionine.Saccharomyces cerevisiae is one of the best organisms for selenium biotransformation

Ionic Liquids and their Toxicity on the Enzyme Activity and Stability

Molecular interactions are crucial between the enzyme molecules and the surrounding solution in an enzymatic catalysis. Although aqueous solutions used as conventional enzymatic reaction media, non-aqueous enzymology emerges as a major area of biotechnology research and development. Ionic liquids, as new generation of promising alternatives to traditional organic solvents, possess potential industrial enzymatic applications. Enzymes in ionic liquids present enhanced activity, stability, and selectivity. In addition, the potential of ionic liquids in bio-catalysis is raised by high ability of dissolving a wide variety of substrates and their extensively tunable solvent properties through appropriate modification of the cations and anions. However, despite the bio-friendly nature of ionic liquids for enzymatic reactions, their growing interests increase concerns associated with toxicity and environmental pollution of such compounds. This mini-review presents a brief highlight of the contemporary knowledge of enzymes activity and stability in ionic liquids and the environmental influences regarding the potential risks related to the growing applications of these green solvents.HIGHLIGHTS•Conventional organic solvents can be replaced by ionic liquids as green solvents.•Ionic liquids are used as additives, catalysts, or reaction media in industries.•Advantages and disadvantages of ionic liquids are discussed.•Potential environmental hazards linked to application of ionic liquids are highlighted.•The environmental fate needs to be considered in designing safer ionic liquids

Two Different Endotracheal Tube Securing Techniques: Fixing Bandage vs. Adhesive Tape

Introduction: Emergency physicians should secure Endotracheal tubes (ETT) properly in order to prevent unplanned extubation (UE) and its complications. Despite various available endotracheal tube holders, using bandages or tape are still the most common methods used in this regards. Objective: This study aimed to compare adhesive tape (AT) versus fixing bandage (FB) method in terms of properly securing ETT. Methods: This was an observational longitudinal trial. All patients older than 15-years-old admitted to the ED who had indication for ETT insertion were eligible. Patients were randomly assigned to one of the two groups in which AT or FB was applied. All patients were observed thoroughly in the first 24 hours after intubation. Using a pre-prepared checklist, encountered UE rate and other data were recorded. Results: Seventy-two patients with the mean age of 55.98 ± 18.39 years were finally evaluated of which 38 cases (52.8%) were male. In total, 12% of patients in our study experienced unplanned extubation. Less than 12% of the patients experienced complete UE; there was no statistically significant difference between the two groups (p = 0.24). Comparison of UE with age showed no significant difference (p = 0.89). Male patients experienced more UE, but this was not statistically significant (p = 0.44). Conclusion: It is likely that whether the AT method or FB was applied for securing the ETT in emergency departments, there was no significant difference in rates of unplanned extubation

Comparison of intracytoplasmic sperm injection outcomes in azoospermic men who underwent testicular sperm extraction vs. microdissection testicular sperm extraction: A cross-sectional study

Background: Outcomes of intracytoplasmic sperm injection (ICSI) may be different in azoospermic men who undergo testicular sperm extraction (TESE) vs. microdissection-TESE (micro-TESE). Objective: This study was conducted to compare the ICSI outcomes in men who underwent TESE vs. micro-TESE due to obstructive azoospermia and nonobstructive azoospermia, respectively. Materials and Methods: A total of 310 azoospermic men who underwent ICSI from September 2016 to September 2020 were enrolled in this cross-sectional study and divided into two groups (172 cases in the TESE and 138 cases in the micro-TESE group). The paternal and maternal age, and the fertilization, biochemical pregnancy, abortion and live birth rates were compared between the two groups. Results: Maternal mean age was significantly higher in the TESE group (34.9 ± 4.2 yr vs. 32.3 ± 5.7 yr). The fertilization and biochemical pregnancy rates were significantly higher in the TESE group, but the abortion rate was similar in the two groups. The live birth rate was higher in the TESE group, but this difference was not significant (p = 0.06). Also, the maternal and paternal age did not affect ICSI outcomes. Conclusion: Individuals who underwent TESE had higher fertilization and biochemical pregnancy rates than those who underwent micro-TESE, but the live birth rate was not significantly different. Keywords: Intracytoplasmic sperm injection, Azoospermia, Testicular sperm extraction, Microdissection testicular sperm extraction, Pregnancy outcome

Success rate and ART outcome of microsurgical sperm extraction in non obstructive azoospermia: A retrospective study

Background: The management of non-obstructive azoospermia (NOA) disease relies on microdissection testicular sperm extraction (micro-TESE). Few studies have assessed the role of micro-TESE in men with NOA in our country. Objective: The aim of the current study was to investigate the success rate of micro- TESE. Materials and Methods: This retrospective descriptive-analytical study was conducted on 463 men with NOA in Yazd Reproductive Sciences Institute during September 2017 through September 2019. Sperm were retrieved and frozen according to the rapid sperm freezing protocol. After preparing the oocyte of the male partner’s spouse, sperms were thawed and then entered the intracytoplasmic sperm injection process. The clinical pregnancy of individuals was confirmed via ultrasound. Demographic data were extracted from medical records. Results: The success rate of micro-TESE was 38% and successful fertilization, biochemical pregnancy, clinical pregnancy, and live birth were observed in 111 (85.4%), 29 (22.3%), 29 (22.3%) and 14 (10.7%) men, respectively. A significant difference was seen between the two groups, regarding age (p = 0.01). In addition, the mean follicle-stimulating hormone in men with positive micro-TESE was significantly lower than in men with negative micro-TESE (p = 0.02). Conclusion: The success of pregnancy in couples with NOA managed via micro-TESE was significant. The study found that the success rate of micro-TESE was higher in older men and in those with lower follicle-stimulating hormone levels. Key words: Azoospermia, Fertilization, Microdissection, Testicular

Comparison of zeta potential and physiological intracytoplasmic sperm injection in obtaining sperms with a lower DNA fragmentation index: A cross-sectional study

Background: The sperm DNA fragmentation index (DFI) is one of the men’s reproductive health criteria that affects assisted reproductive technique outcomes. Efforts in obtaining high-quality mature sperms seem to be necessary. Advanced sperm selection techniques (including physiological intracytoplasmic sperm injection [PICSI], zeta potential, microfluidic, etc.) have gained popularity in this regard. Objective: The study aimed to compare the efficacy of zeta potential and PICSI sperm selection in obtaining sperms with better DNA integrity. Materials and Methods: In this cross-sectional study, 48 couples were enrolled where the male partner had increased sperm DFI in his ejaculated sample and the female was in normal reproductive health. For each male partner, the semen sample was processed with zeta potential and PICSI techniques, then the sperm DFI of neat semen was compared to zeta and PICSI samples by the sperm chromatin dispersion test. Results: Data showed that both the zeta potential and PICSI technique decreased sperm DFI in comparison with the neat semen sample (p < 0.001 for both). In addition, there was a statistically significant difference in sperm DFI between the PICSI and zeta potential samples (p < 0.01). Conclusion: The current study showed that both zeta potential and PICSI could result in sperm with a lower DFI. However, PICSI seems to be superior to zeta potential in this regard. Key words: PICSI, ZETA potential, Hyaluronic acid, DNA integrity

Predisposing Factors for Methadone Poisoning in Children Hospitalized at ‎Kerman Afzalipour Hospital, Iran

Background: Methadone is a synthetic opioid that has been used to relieve severe pain in addiction withdrawal. Unfortunately, due to non-standard supply and storage, the incidence of poisoning and deaths caused by this drug is increasing daily. The purpose of this study was to determine the underlying causes of methadone poisoning in children admitted to Kerman Afzalipour Hospital, Kerman University of Medical Sciences, Iran, during 2012. Methods: This cross-sectional study was performed on 105 children diagnosed with methadone poisoning and admitted to the pediatric emergency ward at Kerman Afzalipour Hospital. The required information was recorded through interviews with parents, patient examination, and if necessary telephone calls with the parents. The data were analyzed using SPSS software. Findings: Mean age of children was 3.9 ± 2.4 years and 59.0% of them were boys. Most parents had a high school diploma or a lower level of education. In all cases, a family member or relative, or at least one person in a party they attended was an addict. In most cases, methadone was fed to the child by mistake instead of water or other drugs. Parental substance abuse, employment status, and family income were significantly associated with methadone poisoning. Conclusion: Training of methadone storage in individuals who need to use this drug can help to prevent accidental ingestion and poisoning of children

Responsible sourcing of critical metals

This is the author accepted manuscript. The final version is available from Mineralogical Society of America via the DOI in this recordMost critical raw materials, such as the rare earth elements (REE), are starting products in long manufacturing supply chains. It is difficult for consumers, buying cars or smartphones for example, to engage with the original mines and demand environmental and social best practice. Geoscientists can become involved in responsible sourcing because geology is related to environmental impact factors such as energy requirements, resource efficiency, radioactivity and the amount of rock mined. The energy and material inputs and emissions and waste from mining and processing can be quantified using life cycle assessment (LCA). Preliminary LCA studies for REE show little over all difference between ‘hard rocks’ such as carbonatites and easily leachable ion adsorption clays, mainly because of the embodied energy in chemicals used for leaching, dissolution and separation.This work is part funded by the NERC SoS RARE project, NE/M011429/1