213 research outputs found
A Hybrid Modified Ant Colony Optimization - Particle Swarm Optimization Algorithm for Optimal Node Positioning and Routing in Wireless Sensor Networks
Wireless Sensor Networks (WSNs) have been widely deployed in hostile locations for environmental monitoring. Sensor placement and energy management are the two main factors that should be focused due to certain limitations in WSNs. The nodes in a sensor network might not stay charged when energy draining takes place; therefore, increasing the operational lifespan of the network is the primary purpose of energy management. Recently, major research interest in WSN has been focused with the essential aspect of localization. Several types of research have also taken place on the challenges of node localization of wireless sensor networks with the inclusion of range-free and range-based localization algorithms. In this work, the optimal positions of Sensor Nodes (SNs) are determined by proposing a novel Hybrid M-ACO – PSO (HMAP) algorithm. In the HMAP method, the improved PSO utilizes learning strategies for estimating the relay nodes\u27 optimal positions. The M-ACO assures the data conveyance. A route discovers when it relates to the ideal route irrespective of the possibility of a system that includes the nodes with various transmission ranges, and the network lifetime improves. The proposed strategy is executed based on the energy, throughput, delivery ratio, overhead, and delay of the information packets
Large outbreak of Crimean-Congo haemorrhagic fever in Iraq, 2022
Background Crimean-Congo haemorrhagic fever (CCHF) is reported sporadically in Iraq. The lack of preventive veterinary activities during 2 years of the coronavirus disease 2019 pandemic (2020 and 2021) led to the largest CCHF outbreak in Iraq since 1979. Objective To describe the epidemiological characteristics of CCHF cases that occurred during the first half of 2022 in Iraq in terms of age, sex, residence, history of contact with another case, and history of contact with animals. Materials and methods This descriptive study included laboratory-confirmed cases of CCHF between 1st January 2022 and 26th June 2022. Frequencies and percentages were used to describe the demographic and epidemiologic criteria of the cases. The epidemic curve of the cases was used to describe the timing and duration of the outbreak. Results In total, there were 219 confirmed cases of CCHF from 1st January 2022 to 26th June 2022. The first confirmed case was reported in March 2022, and cases continued to occur through June 2022. The median age of the cases was 34.5 years. The majority of cases were male (n=130, 59.4%), had an unspecified job (n=126, 57.5%) and lived in southern Iraq (n=142, 64.8%). The first case was reported in week 10 of 2022. Case numbers peaked in week 24 (30 cases were reported), and subsequently declined in week 25 (24 cases were reported). The case fatality rate was 16.4%. Conclusion and recommendations The CCHF outbreak in 2022 was the largest in Iraq since the disease was first reported four decades ago. Identification of CCHF strains in Iraq is recommended, together with exploration of the knowledge, attitudes and practices of high-risk groups for CCHF, and a national survey of CCHF vectors in Iraq
A color-based high temperature extraction method in breast thermogram to classify cancerous and healthy cases using SVM
Breast cancer claims thousands of lives every year. Detecting the disease early can save lives. There is a quite growing research towards detecting cancer from breast thermograms; nevertheless few have investigated role of the color channels on segmentation and feature extraction using different measurements which include sensitivity, accuracy, and specificity. The objective of this research is three fold. Firstly, to investigate the impact of using the green and blue channels on segmenting both the left and right breasts toward improving cancer detection. Secondly, the impact of using features based on three channels: Red and Green and Blue. Thirdly, we compare between the impacts on classification performance when using mean based on a grayscale version of the color image and when using the mean based on three color channels. In this research, we use thermogram images from Brazil. Each patient in the images dataset has undergone a mammogram and based on the mammogram the patient is labeled as being sick or not sick. To classify an image as being normal or not, a histograms-based method is developed first. Extracting the high heat which represents the body temperature that exists in the breast area of the image can give a strong indication of some kind of abnormality present in a breast. Here, we used the histogram based technique to process an image to produce either one that represents the high heat, some high heat or none in the breast and then we correlate some features from the extracted image related to three color channels to support the abnormality indication. Using extracted features and SVM, we achieved high measurements in differentiating between cancerous and healthy images and also noticeable improvement over the original cropped images using the same features
Recombination directionality factor gp3 binds ϕC31 integrase via the zinc domain, potentially affecting the trajectory of the coiled-coil motif
To establish a prophage state, the genomic DNA of temperate bacteriophages normally becomes integrated into the genome of their host bacterium by integrase-mediated, site-specific DNA recombination. Serine integrases catalyse a single crossover between an attachment site in the host (attB) and a phage attachment site (attP) on the circularized phage genome to generate the integrated prophage DNA flanked by recombinant attachment sites, attL and attR. Exiting the prophage state and entry into the lytic growth cycle requires an additional phage-encoded protein, the recombination directionality factor or RDF, to mediate recombination between attL and attR and excision of the phage genome. The RDF is known to bind integrase and switch its activity from integration (attP x attB) to excision (attL x attR) but its precise mechanism is unclear. Here, we identify amino acid residues in the RDF, gp3, encoded by the Streptomyces phage ϕC31 and within the ϕC31 integrase itself that affect the gp3:Int interaction. We show that residue substitutions in integrase that reduce gp3 binding adversely affect both excision and integration reactions. The mutant integrase phenotypes are consistent with a model in which the RDF binds to a hinge region at the base of the coiled-coil motif in ϕC31 integrase
Gated rotation mechanism of site-specific recombination by ϕC31 integrase
Integrases, such as that of the Streptomyces temperate bacteriophage ϕC31, promote site-specific recombination between DNA sequences in the bacteriophage and bacterial genomes to integrate or excise the phage DNA. ϕC31 integrase belongs to the serine recombinase family, a large group of structurally related enzymes with diverse biological functions. It has been proposed that serine integrases use a “subunit rotation” mechanism to exchange DNA strands after double-strand DNA cleavage at the two recombining att sites, and that many rounds of subunit rotation can occur before the strands are religated. We have analyzed the mechanism of ϕC31 integrase-mediated recombination in a topologically constrained experimental system using hybrid “phes” recombination sites, each of which comprises a ϕC31 att site positioned adjacent to a regulatory sequence recognized by Tn3 resolvase. The topologies of reaction products from circular substrates containing two phes sites support a right-handed subunit rotation mechanism for catalysis of both integrative and excisive recombination. Strand exchange usually terminates after a single round of 180° rotation. However, multiple processive “360° rotation” rounds of strand exchange can be observed, if the recombining sites have nonidentical base pairs at their centers. We propose that a regulatory “gating” mechanism normally blocks multiple rounds of strand exchange and triggers product release after a single round
Alarming update on incidence of Crimean-Congo hemorrhagic fever in Iraq in 2023
Objectives: In 2021, large outbreak of Crimean-Congo hemorrhagic fever (CCHF) was reported in Iraq and cases have increased without any significant control measures. To raise awareness about the increasing cases in different regions of Iraq, hence remind the necessity to tackle contributing factors and potential outbreak interventions. Methods: The study included 511 polymerase chain reaction-confirmed CCHF infection cases out of 1827 suspected cases from 18 Provinces from January to August 2023. Approval from the Ministry of Health for data analyzed. Results: Out of 1827 suspected cases, 511 were confirmed positive by polymerase chain reaction. The total case fatality rate (CFR) was 12.7 with varying severity levels among provinces. Erbil had the highest CFR, 38.5, while Sulaimaniya and Anbar report no deaths. Independent t-test showed a significant difference in CFR between provinces west and south of Baghdad compared to north (P <0.05). Trend showed significant surges after Iftar and Adha holidays. Conclusion: Differences in CFR among provinces around the religious ceremonies, highlight the need for one public health intervention strategy. Increased temperatures affected vector behavior. Uncontrolled animal movement with neighboring countries is an important factor. Virus or host determinants can shape the clinical case outcomes, which need clinical and extensive laboratory studies to unravel the reasons leading to death
Phosphorescence by Trapping Defects in Boric Acid Induced by Thermal Processing
The phosphorescence of boric acid (BA, H3BO3) at room temperature is a puzzling phenomenon subject to controversial interpretations although the role of structural defects has not yet been considered. Heat treatments of boric acid cause its transformation into the metaboric phase and amorphous boron oxide (B2O3). The structural changes after thermal processing can create defects that become centers of luminescence and recombination channels in the visible range. In the present work, commercial boric acid is thermally processed at different temperatures. Samples treated between 200 and 400 degrees C exhibit remarkable phosphorescence in the visible range. At approximate to 480 and 528 nm, two distinct phosphorescent emissions occur, associated with trapped charge carriers recombinations identified by thermoluminescence (TL) and electron paramagnetic resonance spectroscopy (EPR). The structural and optical studies suggest that the activation of boric acid phosphorescence after heat treatment is correlated with the presence of defects. The afterglow results from a trapping and detrapping process, which delays the recombination at the active optical centers. Time-dependent density functional study (DFT) of defective BOH molecules and clusters shows the emergence of near UV and blue optical transitions in absorption. These defects trigger the photoluminescence in thermally processed boric acid samples.Boric acid emits phosphorescence in visible range only after dehydration and melting. Defects activate two distinct phosphorescent emissions, with trapping and detrapping process delaying recombination at active optical centers. Time-dependent density functional study reveals near UV and blue optical transitions in absorption due to oxygen vacancies and non-bridging oxygens, triggering photoluminescence.imag
Validity and reliability of Squegg device in measuring isometric handgrip strength
OBJECTIVE: The quantitative measurement of handgrip strength is important in assessing and charting the progress of patients with neuromuscular diseases. The aim of this research was to determine the intra-rater and inter-rater reliability and the validity of the Squegg digital dynamometer. SUBJECTS AND METHODS: Twenty-one females and nine male participants with an age range between 18 and 40 years volunteered for the study. Three testers each took three measurements with a Squegg device and a Jamar dynamometer using standardized measurement techniques. Intra- and inter-tester reliability were calculated using the intra-class correlation coefficient (ICC). To investigate the relationship between hand measures and isometric handgrip strength, the Pearson correlation coefficient test was used. To determine the agreement between the two devices, a Bland Altman plot was constructed, and the concurrent validity of Squegg was calculated. RESULTS: The intra-rater reliability coefficients for both Jamar and Squegg were greater than 0.99 for all three testers, indicating excellent intra-rater reliability. The inter-rater reliability of Jamar (ICC=0.93) and Squegg (ICC=0.87) was excellent. With an ICC of 0.844 and an r-value of 0.720, Squegg with Jamar demonstrates good validity and statistical significance (p=0.001). CONCLUSIONS: The isometric handgrip strength and hand measures showed a moderate correlation in the study population. The Squegg isometric handgrip dynamometer has good concurrent validity and great intra- and inter-rater reliability in healthy individuals. The validity of Squegg in patients with neuromuscular diseases that affect hand function has to be investigated further.</p
Mental stress causes vasoconstriction in subjects with sickle cell disease and in normal controls
Vaso-occlusive crisis (VOC) is a hallmark of sickle cell disease (SCD) and occurs when deoxygenated sickled red blood cells occlude the microvasculature. Any stimulus, such as mental stress, which decreases microvascular blood flow will increase the likelihood of red cell entrapment resulting in local vaso-occlusion and progression to VOC. Neurally mediated vasoconstriction might be the physiological link between crisis triggers and vaso-occlusion. In this study, we determined the effect of mental stress on microvascular blood flow and autonomic nervous system reactivity. Sickle cell patients and controls performed mentally stressful tasks, including a memory task, conflict test and pain anticipation test. Blood flow was measured using photoplethysmography, autonomic reactivity was derived from electrocardiography and perceived stress was measured by the State-Trait Anxiety Inventory questionnaire. Stress tasks induced a significant decrease in microvascular blood flow, parasympathetic withdrawal and sympathetic activation in all subjects. Of the various tests, pain anticipation caused the highest degree of vasoconstriction. The magnitude of vasoconstriction, sympathetic activation and perceived stress was greater during the Stroop conflict test than during the N-back memory test, indicating the relationship between magnitude of experimental stress and degree of regional vasoconstriction. Baseline anxiety had a significant effect on the vasoconstrictive response in sickle cell subjects but not in controls. In conclusion, mental stress caused vasoconstriction and autonomic nervous system reactivity in all subjects. Although the pattern of responses was not significantly different between the two groups, the consequences of vasoconstriction can be quite significant in SCD because of the resultant entrapment of sickle cells in the microvasculature. This suggests that mental stress can precipitate a VOC in SCD by causing neural-mediated vasoconstriction
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