Моделювання динамічних силових характеристик плунжерних токарних патронів з компенсаторами відцентрових сил

Efficient energy transfer was demonstrated in the SrF2:Eu2+, Pr3+ phosphor synthesized by the co-precipitation method. Results obtained with X-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray spectroscopy (XPS), photoluminescence (PL) and decay curves proposed the UV-Vis energy transfer process. The energy transfer process between the Eu2+ and Pr3+ ions in SrF2 was investigated to evaluate the potential of the Eu2+ ion as a sensitizer for the Pr3+ ion. The results proposed that Eu2+ could be a good sensitizer for absorbing the UV photons and efficiently enhancing the Pr3+ emission intensity. The energy transfer process was effective until concentration quenching for the Pr3+ ions occurred. The concentration quenching was attributed to cross-relaxation between the Pr3+ ions. (C) 2016 Author(s).Funding Agencies|South African Research Chairs Initiative of the Department of Science and Technology; National Research Foundation of South Africa; National Research Foundation (NRF); Cluster program of the University of the Free State</p

Evaluation of Antimicrobial Activity of Moringa Oleifera Leaf Extracts Against Pathogenic Bacteria Isolated From Urinary Tract Infected Patients

Antibiotic resistance has increased substantially in recent years and is posing an ever-increasing therapeutic problem. One of the methods to reduce the resistance to antibiotics is by using antibiotic resistance inhibitors from plants. The aim of this study is to evaluate the antibacterial properties of aqueous, petroleum ether and methanolic leaf extracts of Moringa oleifera plant against pathogenic bacteria isolated from urinary tract infected patients and five standard strains of American type culture collection. The antibacterial activity of Moringa oleifera leaf extracts was determined in vitro, using Cup plate method, and compared with sensitivity testing of some antibiotic agents using disc diffusion method. The results obtained showed that all concentration of methanolic extracts of Moringa oleifera had high inhibitory effects on S. aureus ATCC25923, K. pneumoniae ATCC35637 standard strains and the S. aureus, S. saprophyticus and E.coli isolated from UTI. The three concentration of water extract had inhibitory effects only on Proteus vulgaris NCTC8196 strain. The petroleum ether extracts showed no inhibitory activity on any organism. These results were compared with standard antibiotics Amikacin, Ciprofloxacin, and Norfloxacin which showed moderate sensitivity against S. aureus and Amikacin was completely resistant to K. pneumoniae isolated from UTI. These results provide valuable information that Moringa oleifera hold great promise as highly effective antibacterial agents

Thyroid disorders, epidemiology and outcome among patients in South Western region: Southern Saudi Arabia

Background: Thyroid gland may have a group of a medical condition that affects its main function. The thyroid gland is located at the front of the neck and produces thyroid hormones. The released hormones go through the blood to many body organs for regulating their function, meaning that it is an endocrine organ. These hormones normally act in the body to regulate energy use, infant development, and childhood development. The study aimed to assess the epidemiology of thyroid disorders among cases in the south-western region, Saudi Arabia, and to assess the reporting quality for these cases data.Methods: A retrospective record based descriptive approach was used through reviewing medical records of all cases that were admitted and diagnosed as thyroid related disorders for different indications in the main hospital (king Khalid Hospital) during the period from January 2018 to January 2020. Data extracted throng pre-structured questionnaire including patient's bio-clinical data, preoperative radiological and laboratory investigations. Also, laryngoscope pre and post operatively was reviewed to record findings.Results: The study included 405 cases with thyroid disorders whose ages ranged from 15 to 71 years old with a mean age of 30.5±10.6 years. Females were 82.7% of the included cases, and 83.8% were Saudi. Thyroid related symptoms were recorded for 1-2 years among 58.1% of the cases and for more than 5 years among 15.8%. Thyroid enlargement was recorded for 73.1% of the cases. The multinodular enlargement was recorded for 53.5% of the cases followed with diffuse thyroid enlargement (27.3%). Regarding the type of surgery undergone, total thyroidectomy was the most recorded followed with lobectomy.Conclusions: The study revealed that the majority of the cases were females at middle age presented with benign lesions with Euthyroid status. The most important conclusion was the significant remarkable underreporting of the different clinical data for the cases with many missing items

Evaluation of Cell Cycle Arrest in Estrogen Responsive MCF-7 Breast Cancer Cells: Pitfalls of the MTS Assay

Endocrine resistance is a major problem with anti-estrogen treatments and how to overcome resistance is a major concern in the clinic. Reliable measurement of cell viability, proliferation, growth inhibition and death is important in screening for drug treatment efficacy in vitro. This report describes and compares commonly used proliferation assays for induced estrogen-responsive MCF-7 breast cancer cell cycle arrest including: determination of cell number by direct counting of viable cells; or fluorescence SYBR®Green (SYBR) DNA labeling; determination of mitochondrial metabolic activity by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay; assessment of newly synthesized DNA using 5-ethynyl-2′-deoxyuridine (EdU) nucleoside analog binding and Alexa Fluor® azide visualization by fluorescence microscopy; cell-cycle phase measurement by flow cytometry. Treatment of MCF-7 cells with ICI 182780 (Faslodex), FTY720, serum deprivation or induction of the tumor suppressor p14ARF showed inhibition of cell proliferation determined by the Trypan Blue exclusion assay and SYBR DNA labeling assay. In contrast, the effects of treatment with ICI 182780 or p14ARF-induction were not confirmed using the MTS assay. Cell cycle inhibition by ICI 182780 and p14ARF-induction was further confirmed by flow cytometric analysis and EdU-DNA incorporation. To explore this discrepancy further, we showed that ICI 182780 and p14ARF-induction increased MCF-7 cell mitochondrial activity by MTS assay in individual cells compared to control cells thereby providing a misleading proliferation readout. Interrogation of p14ARF-induction on MCF-7 metabolic activity using TMRE assays and high content image analysis showed that increased mitochondrial activity was concomitant with increased mitochondrial biomass with no loss of mitochondrial membrane potential, or cell death. We conclude that, whilst p14ARF and ICI 182780 stop cell cycle progression, the cells are still viable and potential treatments utilizing these pathways may contribute to drug resistant cells. These experiments demonstrate how the combined measurement of metabolic activity and DNA labeling provides a more reliable interpretation of cancer cell response to treatment regimens

Determination of nitrogen dioxide, sulfur dioxide, ozone, and ammonia in ambient air using the passive sampling method associated with ion chromatographic and potentiometric analyses

Concentrations of nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and ammonia (NH3) were determined in the ambient air of Al-Ain city over a year using the passive sampling method associated with ion chromatographic and potentiometric detections. IVL samplers were used for collecting nitrogen and sulfur dioxides whereas Ogawa samplers were used for collecting ozone and ammonia. Five sites representing the industrial, traffic, commercial, residential, and background regions of the city were monitored in the course of this investigation. Year average concentrations of ≤59.26, 15.15, 17.03, and 11.88 μg/m3 were obtained for NO2, SO2, O3, and NH3, respectively. These values are lower than the maxima recommended for ambient air quality standards by the local environmental agency and the world health organization. Results obtained were correlated with the three meteorological parameters: humidity, wind speed, and temperature recorded during the same period of time using the paired t test, probability p values, and correlation coefficients. Humidity and wind speed showed insignificant effects on NO2, SO2, O3, and NH3 concentrations at 95% confidence level. Temperature showed insignificant effects on the concentrations of NO2 and NH3 while significant effects on SO2 and O3 were observed. Nonlinear correlations (R2 ≤ 0.722) were obtained for the changes in measured concentrations with changes in the three meteorological parameters. Passive samplers were shown to be not only precise (RSD ≤ 13.57) but also of low cost, low technical demand, and expediency in monitoring different locations

Enhanced Pr3+ photoluminescence by energy transfer in SrF2:Eu2+, Pr3+ phosphor

Efficient energy transfer was demonstrated in the SrF2:Eu2+, Pr3+ phosphor synthesized by the co-precipitation method. Results obtained with X-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray spectroscopy (XPS), photoluminescence (PL) and decay curves proposed the UV-Vis energy transfer process. The energy transfer process between the Eu2+ and Pr3+ ions in SrF2 was investigated to evaluate the potential of the Eu2+ ion as a sensitizer for the Pr3+ ion. The results proposed that Eu2+ could be a good sensitizer for absorbing the UV photons and efficiently enhancing the Pr3+ emission intensity. The energy transfer process was effective until concentration quenching for the Pr3+ ions occurred. The concentration quenching was attributed to cross-relaxation between the Pr3+ ions. (C) 2016 Author(s).Funding Agencies|South African Research Chairs Initiative of the Department of Science and Technology; National Research Foundation of South Africa; National Research Foundation (NRF); Cluster program of the University of the Free State</p

Metasurface-Based WPT Rectenna with Extensive Input Power Range in the 900 MHz

In this paper, a rectenna is introduced by making use of an adaptive rectifier topology and a low-cost metasurface based printed antenna to cover a wide-range of input power levels. The low-cost metasurface printed antenna is based on flexible substrates while the rectifier can handle a wide input power range by employing a FET as a switch between low power and high power, which overcomes issues related to failure voltage in conventional rectification devices. The proposed rectifier attains an RF-DC efficiency of more than 40% for an input power ranging from -8 dBm to 25dBm. At 15 dBm, it demonstrates a peak power efficiency of 66% at 915 MHz. The low-cost metasurface-based printed antenna achieved a gain of 3 dBi, a directivity of 5.3 dBi and a radiation efficiency of 57%. The rectenna achieved 40% efficiency over a wide-range of input power from -5 dBm to 23 dBm, making it suitable for Wireless Power Transfer applications