Bubble Plumes in Crossflow: Laboratory and Field Measurements of Their Fluid Dynamic Properties with Application to Lake Aeration and Management

This dissertation presents laboratory experiments of bubble plumes in crossflows and field measurements in managed lakes aerated by bubble plumes to better understand the behavior of bubble plumes in natural environments. The laboratory experiments were conducted to investigate the detailed time-average and turbulent fluctuating velocity field in the wake region behind the bubble column and above the separation height, at which fluid entrained at the base of the plume separates from the bubbles. These measurements are important for developing predictive models for bubble plume dynamics and for quantifying their mixing characteristics. Two field campaigns, at Carvins Cove in Virginia and at Lake Hallwil in Switzerland, were conducted to measure the detailed bottom boundary currents and oxygen exchange across the sediment-water interface for different diffuser operations. These lakes have different bubble plume diffuser types, and they span a range of shape, bathymetry, and environmental forcing. These field data are useful to elucidate the physical mechanisms by which currents resulting from both natural forcing (e.g., seiches) and artificial forcing (e.g., bubble plumes) affect oxygen uptake at the sediment-water interface, with the ultimate goal of better management of aeration systems in drinking water reservoirs. Experimental techniques applied in the laboratory experiments include Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF). Crossflows were generated in two ways: by towing the source and by forcing a recirculation current. A combination of field equipment was used in the field campaigns, including a microprofiler for temperature and oxygen; point and profiling acoustic Doppler velocimeter (ADV); thermistor chains; conductivity, temperature, and depth (CTD) profiles; and a meteorological station. During the field experiments, the bubble plume flow rate was varied to produce different dynamic and chemical conditions in the lakes. The laboratory experiments present a cohesive view of the flow dynamics in the wake of a bubble plume in crossflow. Using the forced and towed plume validates the analogy of the towed plume to that of the real current. The observations showed that no secondary bubble plume forms above the separation height, but rather the bubble column becomes a continuous source of vertical momentum to the wake region. The resulting vertical velocities impart a rising frame of reference on the separated plume so that its trajectory scales like a buoyant jet despite the absence of buoyancy in the separated fluid. Maximum values of the Reynolds stresses and mixing occur at the base of the separated plumes, and the bubble column elevates both the turbulence intensity and the kinetic energy throughout the wake region. The in situ field measurements provide insight into the role of aeration bubble plumes on the oxygen dynamics at the sediment-water interface. Detailed, simultaneous measurements of turbulence and oxygen uptake in the bottom boundary layer allowed the direct validation of boundary exchange models. The measurements also showed that unsteady operation of the bubble plume results in generation of basin-scale internal waves that drive measurable currents in the bottom boundary layer. Moreover, measurements showed that it is the oxygen concentration outside the diffusive boundary layers that is the dominant mechanism for controlling the uptake at the sediment-water interface

Comparação da concentração de metais pesados em alguns vegetais (aipo, brócolis e alface)

Heavy metal contamination is one of the main environmental and food safety concerns. This study was conducted with the objective of determining the concentration of heavy metals such as cadmium, lead, copper, zinc and iron in stems and leaves in various vegetables (celery, broccoli and lettuce) in Shiraz. The metal concentrations in the vegetable samples were determined by atomic absorption spectroscopy (AAS). The results for the vegetable samples showed that the leaves contained much higher concentrations of heavy metals. The concentrations of Cd detected in the vegetable samples varied from a very low infection to 0.0025 mg / kg; very low infection at 0.51 mg / kg Pb; 0.93 to 2.91 mg / kg Cu. 1.44 to 9.69 mg / kg Zn and 2.54 to 11.05mg / kg Fe. The findings of this study indicated that although most of the sampling plants were contaminated, except for lettuce, other crops have an EDI below the Tolerable Daily Intake (PTDI) recommended by the Institute of Standards and Industrial Research of Iran and the FAO / WHO.La contaminación por metales pesados es uno de las principales preocupaciones ambientales y de seguridad alimentaria. Este studio se realizó con el objetivo de determinar la concentración de metales pesados como cadmio, plomo, cobre, zinc y hierro en tallos y hojas en varios vegetales (apio, brócoli y lechuga) en Shiraz. Las concentraciones de metal en las muestras de vegetales se determinaron mediante espectroscopia de absorción atómica (AAS). Los resultados para muestras de vegetales mostraron que las hojas contenían concentraciones mucho más altas de metales pesados. Las concentraciones de Cd detectadas en las muestras de vegetales variaron desde una infección muy baja hasta 0,0025 mg / kg; infección muy baja a 0,51 mg / kg Pb; 0,93 a 2,91 mg / kg Cu. 1.44 a 9.69 mg / kg Zn y 2.54 a 11.05mg / kg Fe. Los hallazgos de este estudio indicaron que aunque la mayoría de las plantas del muestreo estaban contaminadas, la ingesta diaria estimada de cada metal (EDI) mostró que, excepto la lechuga, otros cultivos tienen un EDI por debajo de la ingesta diaria tolerable (PTDI) recomendada por el Instituto de Normas e Investigación Industrial de Irán y FAO / OMS.A contaminação por metais pesados é uma das principais preocupações ambientais e de segurança alimentar. Este estúdio foi realizado a fim de determinar a concentração de metais pesados tais como cádmio, chumbo, cobre, zinco e ferro em caules e folhas em vários produtos hortícolas (aipo, brócolos e alface) em Shiraz. As concentrações de metais nas amostras vegetais foram determinadas por espectroscopia de absorção atômica (AAS). Os resultados par a as amostras vegetais mostraram que as folhas continham concentrações muito mais altas de metais pesados. As concentrações de Cd detectadas nas amostras vegetais variaram de uma infecção muito baixa a 0,0025 mg / kg; infecção muito baixa a 0,51 mg / kg Pb; 0,93 a 2,91 mg / kg Cu. 1,44 a 9,69 mg / kg Zn e 2,54 a 11,05 mg / kg Fe. Os resultados deste estudo indicaram que, embora a maioria das plantas amostradas foram contaminados, exceto alface, outras culturas têm EDI abaixo da ingestão diária tolerável (PTDI) recomendado pelo Instituto de Padrões e Pesquisa Industrial de Irã e FAO / OMS

Microscopic Evaluation of Cleaning Efficiency of Three Different Nickel-Titanium Rotary Instruments

INTRODUCTION: This study compared the cleaning efficiency of Mtwo, Race and Medin Nickel-Titanium (NiTi) rotary instruments. MATERIALS AND METHODS: Sixty mandibular molar mesial roots were selected with angle curvatures between 25-35 degrees and divided into three groups; each containing 20 teeth. Canals were prepared with the rotary files and irrigated with 2.5% NaOCl solution after each instrument. Total of 5mL of normal saline was used as the final rinse; subsequently the canals were dried with paper points. The amount of debris and smear layer in three parts of the root canal walls was evaluated using SEM and the data were analyzed by using the Kruskal-Wallis test and the Mann-Whitney U test. RESULTS: The results for remnant debris in the coronal part of root canals were similar, whereas in the middle third, Mtwo instruments achieved significantly better results compared to Race and Medin instruments. In the apical third of the root canals more debris was created by Race instruments. CONCLUSION: Overall, Mtwo instruments had greater success in producing clean canals

Two cases of near-complete regression of focal nodular hyperplasia of the liver: Case reports and review of the literature

AbstractWhile regression of focal nodular hyperplasia of the liver is not uncommon, reports of near-complete involution or regression of these lesions are rare. We report two cases of focal nodular hyperplasia that underwent near-complete regression—one in a 27-year-old female that regressed over a period of 4 years, and one in a 46-year-old female that regressed over a 7-year period. Both patients discontinued use of exogenous estrogens between the diagnosis of focal nodular hyperplasia and its subsequent regression. Although contemporary cross-sectional imaging has improved the ability to detect and follow these lesions, few studies examining the natural history of focal nodular hyperplasia have been conducted. We discuss pertinent imaging findings on magnetic resonance imaging and computed tomography, and review the literature on regression of focal nodular hyperplasia and the effects of endogenous hormones and exogenous hormone therapy

Sitagliptin Suppresses Apoptotic Cell Death and Histological Changes in the Ovaries of Rats with Polycystic Ovary Syndrome

Background and Aim: Polycystic ovary syndrome (PCOS) is the most typical endocrine disorder affecting reproductive-aged women. The patients with PCOS show decreased follicular granule cells' maturation in their ovaries, probably associated with cell apoptosis. This study was designed to investigate Sitagliptin's protective effect against the apoptotic mechanism in PCOS via evaluating apoptosis rate and the mRNA expressions of apoptotic and anti-apoptotic molecules in PCOS rats. Methods: PCOS was induced by injection of estradiol valerate (4 mg/kg, I.M.). Twenty-two female rats divided into four groups: Control (n=5), PCOS+Vehicle (n=5), PCOS+ Sitagliptin 25 mg/kg (n=6) and PCOS+ Sitagliptin 50 mg/kg (n=6). Hematoxylin and eosin staining were used to determine qualitative changes in the ovary follicles. The apoptotic index was examined by TUNEL assay, and the quantitative polymerase chain reaction was performed to detect expression levels of Bax and Bcl-2. Results: Bax mRNA expression was up-regulated (1.38-folds), and Bcl-2 mRNA expression was down-regulated (0.45-folds) in PCOS rats' ovarian tissues. Sitagliptin did not change Bax expression but increased the Bcl-2 mRNA expression (1.95-folds). The apoptosis index was increased in the PCOS group compared with the control group. The number of cystic follicles and pre-antral follicles increased the number of corpus luteum was decreased in PCOS rats compared to control rats. Sitagliptin decreased apoptosis rate and prevented the increase of cystic and pre-antral follicle numbers compared to the PCOS group. Conclusion: In conclusion, Sitagliptin might have a major role in preventing PCOS development due to its anti-apoptotic properties on PCOS rats' ovaries. *Corresponding Author: Mohammad Ebrahim Rezvani, Email: [email protected]; ORCID: https://orcid.org/0000-0001-6146-806X Please cite this article as: Safaeian A, Zare Mehrjerdi F, Yadegari M, Ebrahim Rezvani M. Sitagliptin Suppresses Apoptotic Cell Death and Histological Changes in the Ovaries of Rats with Polycystic Ovary Syndrome. Arch Med Lab Sci. 2021;7:1-9 (e22). https://doi.org/10.22037/amls.v7.3495

Illustration as a Philosophy Training Tool for Children: analysis of image text in three works by Shell Silverstein and Wolf Erlbruch

This article qualitatively introduces the use of illustrations in children's books as a mediator of intellectual understanding and critical thinking. To show the importance of teaching philosophy with the help of illustration. A Philosophical teaching through picture books enables the development of children's cognitive abilities and it helps them to think and act according to the needs of the society in which they live. Regarding the teaching of philosophy to children, theorists such as Matthew Lipman have developed programs that have been used in recent years. In this article, in addition to the description of Lippmann's method, which emphasizes the literary text, the possibilities of teaching through illustration are examined. The data collection method of this research is based on the information obtained from the library study and internet search, which, while explaining the characteristics of imagery in teaching philosophy to children, selectively examines the relationship between concepts and images in two works by Silverstein and one by Wolff Erlbruch describes and analyzes. The findings show that the ambiguity of abstract forms in Silverstein's works, as well as the interpretability of color connotations in Erlbruch's works, can provide the possibility of questioning, thinking, and subsequently inner knowledge and, finally, the intellectual development of children and make them self-knowledge, self-improvement, and prepare a better society. In this way, it is necessary to pay special attention to all dimensions and elements of children's books so that a direct relationship between the book and the child is formed

Development and characterization of nanostructured pharmacosomal mesophases: An innovative delivery system for bioactive peptides

Purpose: To potentially enhance the bioavailability and extend the bioactivity effectiveness of Isoleucine-Proline-Proline (IPP, an antihypertensive bioactive peptide of dairy origin), a novel Lyotropic Liquid Crystalline Pharmacosomal Nanoparticle (LLCPNP) was synthesized, and its physicochemical and technological characteristics were studied. Methods: LLCPNPs precursors were developed using IPP and soy phosphatidylcholine via complex formation. Polarized light microscopy, small angle X-ray scattering, differential scanning calorimetry, dynamic light scattering and Fourier transform infrared spectroscopy were employed to characterize the physicochemical properties of the nanoparticles. The in-vitro release and its related mechanisms were also studied. Results: Fourier transform infrared spectroscopy confirmed the complexation between the components of LLCPNPs. Phase behavior evaluation by polarized light microscope showed the characteristic birefringent texture. These findings along with those of small angle X-ray scattering and differential scanning calorimetry proved the formation of lamellar LLCPNPs. These particles represented nanometric size (<100 nm), high incorporation efficiency (93.72%) and proper physicochemical stability during long-term storage. In-vitro studies demonstrated a sustained release behavior fitted to non-Fickian diffusion and Higuchi kinetic models. Conclusion: The present study results emphasized that LLCPNPs could be proposed as an unrivaled carrier to promote the bioavailability, stability and shelf-life of nutraceutical and biopharmaceutical formulations containing bioactive peptides

Assessment the prevalence of high-risk human papillomavirus types 16 and 18 in 15 to 45 years old women

Background: Cervical cancer is the fourth most common cancer in incidence and the first genital cancer in women around the world, which 95% of them are related to human papillomavirus (HPV) infections. The risk of cervical cancer increases 10-12 time in women with HPV infection. This study aim to evaluate the prevalence of high-risk HPV infections among 15-45 years old women.Materials and Methods: This cross sectional study was carried out on 92 normal women who admitted at Semnan hygiene center and has 15-45 years old. Cervical samples were collected using Cytobrush cell collector and consequently DNA extraction was performed using commercial DNA extraction kit. Polymerase Chain Reaction (PCR) was done using HPV (GP5, GP6) universal primers accompanied by positive and negative control in each PCR run. In order to extracted DNA template quality control, actin gene used as housekeeping gene.Results: In this investigation, study subjects age range found to be 15-45 with mean of 30±0.9 years old. HPV infection was not found in patient group. Thus, further approach in order to HPV16 and HPV18 types detection, was not performed. However, other studies represented low to moderate prevalence for HPV in some regions of Iran.Conclusion: Cervical cancer is one the major health concern and the fourth most common cancer around the world. This cancer is more common in developing countries than developed countries due to lack of screening program. Regard to possible high prevalence rate of HPV virus and its association with cervical cancer, we suggest further determination of the HPV prevalence as well as planning in large-scale vaccination in high risk group

Effects of Bubble Plumes on Lake Dynamics, Near-Bottom Turbulence, and Transfer of Dissolved Oxygen at the Sediment-Water Interface

We quantify the lake dynamics, near-bottom turbulence, flux of dissolved oxygen (DO) across the sediment-water interface (SWI) and their interactions during oxygenation in two lakes. Field observations show that the lake dynamics were modified by the bubble plumes, showing enhanced mixing in the near-field of the plumes. The interaction of the bubble-induced flow with the internal density structure resulted in downwelling of warm water into the hypolimnion in the far-field of the plumes. Within the bottom boundary layer (BBL), both lakes show weak oscillating flows primarily induced by seiching. The vertical profile of mean velocity within 0.4 m above the bed follows a logarithmic scaling. One lake shows a larger drag coefficient than those in stationary BBLs, where the classic law-of-the-wall is valid. The injection of oxygen elevated the water column DO and hence, altered the DO flux across the SWI. The gas transfer velocity is driven by turbulence and is correlated with the bottom shear velocity. The thickness of the diffusive boundary layer was found to be consistent with the Batchelor length scale. The dynamics of the surface renewal time follow a log-normal distribution, and the turbulent integral time scale is comparable to the surface renewal time. The analyses suggest that the effect of bubble plumes on the BBL turbulence is limited and that the canonical scales of turbulence emerge for the time-average statistics, validating the turbulence scaling of gas transfer velocity in low-energy lakes

Effects of Bubble Plumes on Lake Dynamics, Near-Bottom Turbulence, and Transfer of Dissolved Oxygen at the Sediment-Water Interface

We quantify the lake dynamics, near-bottom turbulence, flux of dissolved oxygen (DO) across the sediment-water interface (SWI) and their interactions during oxygenation in two lakes. Field observations show that the lake dynamics were modified by the bubble plumes, showing enhanced mixing in the near-field of the plumes. The interaction of the bubble-induced flow with the internal density structure resulted in downwelling of warm water into the hypolimnion in the far-field of the plumes. Within the bottom boundary layer (BBL), both lakes show weak oscillating flows primarily induced by seiching. The vertical profile of mean velocity within 0.4 m above the bed follows a logarithmic scaling. One lake shows a larger drag coefficient than those in stationary BBLs, where the classic law-of-the-wall is valid. The injection of oxygen elevated the water column DO and hence, altered the DO flux across the SWI. The gas transfer velocity is driven by turbulence and is correlated with the bottom shear velocity. The thickness of the diffusive boundary layer was found to be consistent with the Batchelor length scale. The dynamics of the surface renewal time follow a log-normal distribution, and the turbulent integral time scale is comparable to the surface renewal time. The analyses suggest that the effect of bubble plumes on the BBL turbulence is limited and that the canonical scales of turbulence emerge for the time-average statistics, validating the turbulence scaling of gas transfer velocity in low-energy lakes