Analysis and optimization of process parameters in abrasive waterjet contour cutting of AISI 304L

Abrasive waterjet machining is applied in various industries for contour cutting of heat-sensitive and difficult-to-cut materials like austenitic stainless steel 304L, with the goal of en-suring high surface integrity and efficiency. In alignment with this manufacturing aspiration, experimental analysis and optimization were carried out on abrasive waterjet machining of austenitic stainless steel 304L with the objectives of minimizing surface roughness and maximizing material removal rate. In this machining process, process parameters are critical factors influencing contour cutting performance. Accordingly, Taguchi’s S/N ratio method has been used in this study for the optimization of process parameters. Further in this work, the impacts of input parameters are in-vestigated, including waterjet pressure, abrasive mass flow rate, traverse speed and material thickness on material removal rate and surface roughness. The study reveals that an increasing level of waterjet pressure and abrasive mass flow rate achieved better surface integrity and higher material removal values. The average S/N ratio results indicate an optimum value of waterjet pressure at 300 MPa and abrasive mass flow rate of 500 g/min achieved minimum surface roughness and maximum material removal rate. It was also found that an optimized value of a traverse speed at 90 mm/min generates the lowest surface roughness and 150 mm/min produces the highest rate of material removed. Moreover, analysis of variance in the study showed that material thickness was the most influencing parameter on surface roughness and material removal rate, with a percentage contribution ranging 90.72–97.74% and 65.55–78.17%, respectively

Quercetin and cancer: New insights into its therapeutic effects on ovarian cancer cells

Ovarian cancer is known as a serious malignancy that affects women's reproductive tract and can considerably threat their health. A wide range of molecular mechanisms and genetic modifications have been involved in ovarian cancer pathogenesis making it difficult to develop effective therapeutic platforms. Hence, discovery and developing new therapeutic approaches are required. Medicinal plants, as a new source of drugs, could potentially be used alone or in combination with other medicines in the treatment of various cancers such as ovarian cancer. Among various natural compounds, quercetin has shown great anti-cancer and anti-inflammatory properties. In vitro and in vivo experiments have revealed that quercetin possesses a cytotoxic impact on ovarian cancer cells. Despite obtaining good results both in vitro and in vivo, few clinical studies have assessed the anti-cancer effects of quercetin particularly in the ovarian cancer. Therefore, it seems that further clinical studies may introduce quercetin as therapeutic agent alone or in combination with other chemotherapy drugs to the clinical setting. Here, we not only summarize the anti-cancer effects of quercetin but also highlight the therapeutic effects of quercetin in the ovarian cancer. © 2020 The Author(s)

Comparison of electronic versus conventional assessment methods in ophthalmology residents; a learner assessment scholarship study

Background: Assessment is a necessary part of training postgraduate medical residents. The implementation of methods located at the �shows how� level of Miller�s pyramid is believed to be more effective than previous conventional tools. In this study, we quantitatively compared electronic and conventional methods in assessing ophthalmology residents. Methods: In this retrospective study, eight different conventional methods of assessment including residents� attendance, logbook, scholarship and research skills, journal club, outpatient department participation, Multiple Choice Question (MCQ), Objective Structured Clinical Examination (OSCE), and professionalism/360-degree (as one complex) were used to assess 24 ophthalmology residents of all grades. Electronic media consisting of an online Patient Management Problem (e-PMP), and modified electronic OSCE (me-OSCE) tests performed 3 weeks later were also evaluated for each of the 24 residents. Quantitative analysis was then performed comparing the conventional and electronic assessment tools, statistically assessing the correlation between the two approaches. Results: Twenty-four ophthalmology residents of different grades were included in this study. In the electronic assessment, average e-PMP scores (48.01 ± 12.40) were much lower than me-OSCE (65.34 ± 17.11). The total average electronic score was 56.67 ± 11.28, while the total average conventional score was 80.74 ± 5.99. Female and male residents� average scores in the electronic and conventional method were (59.15 ± 12.32 versus 83.01 ± 4.95) and (55.19 ± 10.77 versus 79.38 ± 6.29), respectively. The correlation between modified electronic OSCE and all conventional methods was not statistically significant (P-value >0.05). Correlation between e-PMP and six conventional methods, consisting of professionalism/360-degree assessment tool, logbook, research skills, Multiple Choice Questions, Outpatient department participation, and Journal club active participation was statistically significant (P-value < 0.05). The overall correlation between conventional and electronic methods was significant (P-value = 0.017). Conclusion: In this study, we conclude that electronic PMP can be used alongside all conventional tools, and overall, e-assessment methods could replace currently used conventional methods. Combined electronic PMP and me-OSCE can be used as a replacement for currently used gold-standard assessment methods, including 360-degree assessment. © 2021, The Author(s)

Motion Rail: A Virtual Reality Level Crossing Training Application

This paper presents the development and usability testing of a Virtual Reality (VR) based system named 'Motion Rail' for training children on railway crossing safety. The children are to use a VR head mounted device and a controller to navigate the VR environment to perform a level crossing task and they will receive instant feedback on pass or failure on a display in the VR environment. Five participants consisting of two male and three females were considered for the usability test. The outcomes of the test was promising, as the children were very engaging and will like to adopt this training approach in future safety training

Rationalising the role of Keratin 9 as a biomarker for Alzheimer’s disease

Keratin 9 was recently identified as an important component of a biomarker panel which demonstrated a high diagnostic accuracy (87%) for Alzheimer’s disease (AD). Understanding how a protein which is predominantly expressed in palmoplantar epidermis is implicated in AD may shed new light on the mechanisms underlying the disease. Here we use immunoassays to examine blood plasma expression patterns of Keratin 9 and its relationship to other AD-associated proteins. We correlate this with the use of an in silico analysis tool VisANT to elucidate possible pathways through which the involvement of Keratin 9 may take place. We identify possible links with Dickkopf-1, a negative regulator of the wnt pathway, and propose that the abnormal expression of Keratin 9 in AD blood and cerebrospinal fluid may be a result of blood brain barrier dysregulation and disruption of the ubiquitin proteasome system. Our findings suggest that dysregulated Keratin 9 expression is a consequence of AD pathology but, as it interacts with a broad range of proteins, it may have other, as yet uncharacterized, downstream effects which could contribute to AD onset and progression

DNA methylation of intragenic CpG islands depends on their transcriptional activity during differentiation and disease

The human genome contains ∼30,000 CpG islands (CGIs). While CGIs associated with promoters nearly always remain unmethylated, many of the ∼9,000 CGIs lying within gene bodies become methylated during development and differentiation. Both promoter and intragenic CGIs may also become abnormally methylated as a result of genome rearrangements and in malignancy. The epigenetic mechanisms by which some CGIs become methylated but others, in the same cell, remain unmethylated in these situations are poorly understood. Analyzing specific loci and using a genome-wide analysis, we show that transcription running across CGIs, associated with specific chromatin modifications, is required for DNA methyltransferase 3B (DNMT3B)-mediated DNA methylation of many naturally occurring intragenic CGIs. Importantly, we also show that a subgroup of intragenic CGIs is not sensitive to this process of transcription-mediated methylation and that this correlates with their individual intrinsic capacity to initiate transcription in vivo. We propose a general model of how transcription could act as a primary determinant of the patterns of CGI methylation in normal development and differentiation, and in human disease.</p

Ultra Wide Band Low Noise Amplifier for Communication Receivers in 0.18 um CMOS technology

This paper presents an inductorless low-noise amplifier (LNA) design for an ultra-wideband (UWB) receiver frontend. A current-reuse gain-enhanced noise canceling architecture is proposed, and the properties and limitations of the gainenhancement stage are discussed. Capacitive peaking is employed to improve the gain flatness and 3-dB bandwidth, at the cost of absolute gain value. The LNA circuit is fabricated in a 0.18-microm triple-well CMOS technology. Measurement resultnbspnbsp goodnbsp matching in the implementations and a small-signal gain of 11 dB and a 3-dB bandwidth of 2ndash9.6 GHz are obtained. The LNA consumes 19 mW from a low supply voltage of 1.5 V. It is shown that the LNA designed without on-chip inductors achieves comparable performances with inductor-based designs. The silicon area is reduced significantly in the inductorless design, the LNA core occupies only 0.05 mm2, which is among the smallest reported designs

Pollen morphology of Amygdalus L. [Rosaceae] in Iran

Pollen grain of 16 species and three hybrids of the genus Amygdalus L., representing two subgenera and two sections distributed in Iran were examined by light and scanning electron microscopy. All pollen grains are tricolporate. The shape of grains varies from subprolate through prolate. Regarding outline, in polar view, pollen grains are triangular-circular and in equatorial view, elliptic. Regarding sculpturing of exine, the frequent type like many members of family Rosaceae is striate with or without perforations that can be subdivided into three subtypes: type I (A-B), type II (A-B) and type V. In three species, A. trichamygdalus, A. spinosissima and A. orientalis, exine sculpture type is completely different. In the first species is rugulate, in the second species is reticulate and in A. orientalis, it is gemmate-perforate. Ornamentation of ridges (muri) in the striate sculpture is parallel to ectocolpus. Number of perforations in tectum, diameter of them, striae intervals and the thickness of ridges varies among studied taxa. The striae have different depth and slope. Results showed that among pollen grain characters, shape is useful character solely for separating of taxonomic ranks in Iranian Amygdalus specially in subgeneric or section level

Infrared temperature measurement and increasing infrared measurement accuracy in the context of machining process

One of the major challenges in the machining process is measuring the temperature accurately which has a considerable importance in calibrating finite element models and investigating thermodynamic of machining process. In the present paper, one of the effective methods for measuring temperature in the machining processes - i.e. infrared imaging - is used and effective parameters which increase measurement accuracy are investigated. One of the most effective parameter in the temperature measurement accuracy of infrared imaging is extracting and calibrating the emissivity coefficient for different temperature ranges. The obtained results show that the lack of precision calibration of the emissivity for different temperature ranges may cause high error in the measurement results. To measure temperature, several experiments are performed for turning a thin walled workpiece which is made of aluminium alloy Al-7075 and the effects of the machining parameters and tool material - polycrystalline diamond (PCD) and cemented carbide - are studied. Based on the achieved results, it can be concluded that the generated temperature in the cutting area can be decreased significantly by using PCD tools and selecting appropriate machining parameters