189 research outputs found
Thermal Diffusivity of Zinc Aluminum – Layered Double Hydroxide Using Photoflash Technique
Thermal diffusivity of zinc aluminum layered double hydroxide (Zn-Al-LDH) was
measured by using photoflash technique. It used a simple camera flash and
polyvinlidene diflouride (PVDF) film as signal generating source and detector
respectively.
Three series of sample were prepared at pH 7, 8 and 10 and with molar ratios of Zn to Al
in a range from 2 to 6 (Zn/Al = 2, 3, 4, 5 and 6).
The ZnO peaks appeared in x-ray diffraction pattern for all samples except for samples
prepared at pH 7 with ratio 2 and 3 (Zn/Al = 2 and 3) and sample prepared at pH 8 with
ratio 4. The ZnO peaks observed were between 2 = 30° to 2 = 37°. Thermal diffusivity for all three series samples (pHs 7, 8 and 10) was measured at room
temperature. The thermal diffusivity for all three series of samples was found to increase
for the case of molar ratio 2 to 6.
The thermal diffusivity for Zn-Al-LDH at different ratios of Zn-Al-LDH increased with
increasing ratio of Zn to Al. The increasing of thermal diffusivity is due to increasing of
ZnO. Thermal diffusivity at pH 7, increased from 0.15 10−6m2 / s × to 0.22 10−6m2 / s × .
Thermal diffusivity of sample prepared at pH 8 increased from 0.16 10−6m2 / s × to
0.20 10−6m2 / s × while at pH 10, if increased from 0.20 10−6m2 / s × to 0.25 10−6m2 / s × .
Thermal diffusivity at pH 7 has the lowest value and at pH 10 has the highest value.
The sample prepared at pH 7 with ratio 4 (Zn/Al = 4) was heat-treated at different
temperature from 200°C to 600°C, prior to thermal diffusivity measurement at room
temperature.
In the case of heat treated samples, the thermal diffusivity increased from
0.25 10−6m2 / s × to 0.40 10−6m2 / s × with increasing treatment temperature
Increased rate of elective cesarean delivery following assisted reproductive technology: A letter to the editor
This is a Letter to Editor and does not have an abstract
Dynamical Wormhole Solutions in Rastall Theory
Wormhole configurations in Einstein's general theory of relativity (GR)
require exotic matter sources violating the weak energy condition (WEC).
Rastall's theory is a generalization of GR in its matter source considering a
nonconserved energy-momentum (EM) tensor. Hence, on one hand, the nature of
this generalization of the matter source of field equations and, on the other
hand, the possibility of respecting energy conditions for dynamical wormholes
in contrast to static ones motivates us to study the possibility of the
existence of wormhole configurations respecting energy conditions or minimizing
the violations of them in Rastall's modified theory. We derive general
analytical solutions considering a constant redshift function and a particular
equation of state for energy density and pressure profiles. We show that
because of the modification in the EM source of the field equations, there
exist solutions respecting the WEC in the vicinity of the wormhole's throat for
specified values of the parameters. Some particular solutions are discussed in
detail.Comment: 24 pages, 8 figure
CD73 a novel marker for the diagnosis of benign and malignant salivary gland tumors
Ecto-5?-nucleotidase (CD73) plays an important role in the development of several types of cancer; however, its prognostic significance in salivary gland tumors remains unknown. The current study was conducted to investigate the expression of CD73 in such tumors. In this retrospective study, immunohistochemical expression of CD73 was evaluated in 25 pleomorphic adenomas, 20 mucoepidermoid carcinomas and 20 adenoid cystic carcinomas using the Envision technique. Labeling indices of CD73 expression were calculated and compared between lesions. Immunohistochemical analysis demonstrated that the CD73 expression was significantly higher in salivary gland tumors than in normal salivary gland tissue (p0.05). The findings suggest that CD73 can be an independent and useful biomarker for predicting the clinical behavior of salivary gland tumors
Prenatal attachment in pregnancy following assisted reproductive technology:a literature review
Objective: To summarise the literature on prenatal attachment in pregnancies following Assisted Reproductive Technology (ART). Background: Prenatal attachment can predict the quality of the postpartum parent–infant relationship and is linked to perinatal mental health of the parents and their adjustment to the parental role. It might be expected prenatal attachment will be influenced by fertility treatment such as ART, but there are contradictory results. Methods: In this review, studies with a cross-sectional and longitudinal design, published in 1990–2019 were included. A search was conducted in MEDLINE/PubMed, EMbase, Web of Science and Scopus, and using the Google Scholar search engine. A total of 17 articles were found which met the inclusion criteria and after these articles were reviewed using the STROBE-checklist, 15 articles were included in the study. Results: In most couples who conceived following ART, the level of prenatal attachment was either similar to or higher than in couples who conceive without ART. Conclusions: The findings challenge the idea that infertility problems affect attachment in pregnancies following ART. However, ART- couples may be more susceptible to anxiety due to pregnancy loss and support may be better focused on the pregnancy-related anxiety in these couples rather than any attachment intervention
A Review on Epigenome Editing using CRISPR-based Tools to Rejuvenate Skin Tissues
Genomic activity is controlled by a sophisticated series of cell functions known as the epigenome. The creation of tools capable of directly altering various processes is required to unravel this intricacy. Additionally, by employing tailored DNA-binding platforms connected with effector domains to serve as targeted transcription factors or epigenetic modifiers, it is possible to control the chemical modifiers that regulate the genome's activity. Neoplastic disorders have received the most attention in the study of epigenetics, though the epigenome's significance in a variety of disease processes is now well acknowledged. Researchers are inspired to investigate novel approaches to revert these pathogenic alterations to their normal patterns by considering the fact that the epigenome profile of individuals with aging skin cells or other skin disorders, including atopic dermatitis, differs from that of healthy individuals. Here in this review, we discuss the use of CRISPR/dCas9 as a cutting-edge and flexible tool for fundamental studies on chromatin structure, transcription regulation, and epigenetic landscapes, as well as the potential of this method in these fields. Furthermore, we review on common and recently invented methods to make epigenetic alterations possible in daughter cells after any mitotic differentiations. In the very near future, CRISPR-based epigenomic editing will become a potent tool for comprehending and regulating biological functions
Changes in some chemical properties of saline-sodic soils over time as affected by organic residues: An incubation study
Salinization and sodification of agricultural lands in arid and semi-arid regions of the world are two limiting factors in the crop production. This study was conducted to evaluate the effect of readily available agricultural residues on changing some chemical properties of saline-sodic soils. Wheat, potato, sunflower, and canola residues were separately added into three saline-sodic soils at a rate of 2% by weight and thoroughly mixed with soils. Control and treated soils were incubated for 168 days at a constant moisture and temperature. The pH, electrical conductivity (EC), soluble cations, available nitrate (NO3-) and phosphorous (P), cation exchange capacity (CEC), and exchangeable sodium percentage (ESP) were measured during the incubation. The EC increased in the response to the incorporation of plant residues, whereas the pH was reduced. The application of organic components in soils increased CEC and decreased ESP. The results showed that the maximum reduction in ESP was observed in the potato treatment because of the highest Ca2+ concentration. The average reduction in ESP of treated soil samples at the end of incubation followed this order: 16.1% (potato residue-treated soil) >12.7% (canola residue-treated soil) >11.1% (wheat residue-treated soil) >9.6% (sunflwer residue-treated soil). The potato residue was the most effective amendment in changing the chemical properties of saline-sodic soils in comparison with other organic residues. The results indicated that the application of organic residues had a positive impact on reducing the soil sodicity and improving the soil fertility depending on their chemical composition
The Efficacy of Buccal Infiltration of 4% Articaine and PSA Injection of 2% Lidocaine on Anesthesia of Maxillary Second Molars
Introduction: During the early mixed dentition period, the location of the deciduous maxillary second molar results in ineffectiveness of the infiltration technique in this area. In such cases, administration of posterior superior alveolar (PSA) nerve block is recommended; however, such a technique has some complications. The present study was undertaken to compare the effects of buccal infiltration of 4% Articaine and PSA technique with 2% Lidocaine on the success of anesthesia of maxillary deciduous second molars in 6 to 9-year old children. Methods and Materials: In the present double-blind randomized clinical trial, 56 children aged 6-9 years requiring vital pulp therapy of deciduous maxillary second molar were included. In group 1, 4% Articaine was injected using a buccal infiltration technique. In group 2, 2% Lidocaine was injected using the PSA nerve block technique. After 10 min, the caries was removed and access cavity preparation was instituted. The patients were asked to report the presence or absence of pain during the procedure. Therefore, the existence of pain was measured by the patient's self-report. Data were analyzed with descriptive statistical methods and the chi-squared test. Results: Pain was reported by 6 (21.4%) and 9 (32.1%) subjects in the Articaine and Lidocaine groups, respectively. Chi-squared test did not reveal any significant differences between the two groups (P=0.54). Conclusion: Under the limitations of the present study, there was no significant differences between the results of Articaine buccal infiltration and Lidocaine PSA technique, so Articaine buccal infiltration can be used as a substitute for the PSA technique.Keywords: Articaine; Buccal Infiltration Technique; Deciduous Second Molar; Lidocaine; Posterior Superior Alveolar Nerve Bloc
The effect of melatonin on aerobic capacity and time of exhaustion during a sub-maximum activity in girl students of physical education
Background: Preservation and storage of muscle glycogen is the most important factor limiting the success of individuals in performing the following activities. It has been shown that melatonin supplementation before exercise can maintain glycogen stores. This study aimed to investigate the effect of melatonin consumption (6 mg) on the time of exhaustion during a submaximal-activity and also the maximum oxygen consumption during an increasing activity in physical education girl students of Shahid Chamran University of Ahvaz. Materials and Methods: In this clinical trial study, 13 girls with the mean age of 21.5±1.29 years, the mean weight of 58.36±2.69 kg and vo2max 39.08±4.17 mg/kg/min were participated and received melatonin (6 mg) and placebo (starch capsules) in two complementary steps. Supplements were administered acutely 30 minutes before the exercise. Each test was repeated in placebo and supplement conditions. To ensure the elimination of exercise and supplement impact, the interval of 5 to 7 days was considered between the two tests. The sub-maximal and progressive protocols respectively included running below the maximum intensity (70 of the heart rate reserve) to exhaustion and the Bruce's test on the treadmill. Results: The results showed that consumption of 6 mg melatonin significantly increased the time to reach exhaustion (P=0.01) and the maximum oxygen consumption (P=0.002). Conclusion: It appears that trained girls can use 6 mg of melatonin supplement 30 minutes before starting the exercise to improve endurance performance and aerobic capacity
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