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1.
Sensors (Basel) ; 22(20)2022 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-36298142

RESUMEN

A high-efficiency dual-purpose plasmonic perfect absorber sensor based on LiNbO3 and graphene layers was investigated in this paper for the refractive index and thermal sensing. The sensor design was kept simple for easy fabrication, comprising a LiNbO3 substrate with a quartz layer, thin layer of graphene, four gold nanorods, and a nanocavity in each unit cell. The nanocavity is located in the middle of the cell to facilitate the penetration of EM energy to the subsurface layers. The proposed sensor design achieved an output response of 99.9% reflection, which was easy to detect without having any specialized conditions for operability. The performance of the device was numerically investigated for the biomedical refractive index range of 1.33 to 1.40, yielding a sensitivity value of 981 nm/RIU with a figure-of-merit of 61.31 RIU-1. By including an additional polydimethylsiloxane polymer functional layer on the top, the device was also tested as a thermal sensor, which yielded a sensitivity level of -0.23 nm/°C.


Asunto(s)
Grafito , Refractometría , Cuarzo , Temperatura , Oro , Dimetilpolisiloxanos
2.
Pak J Pharm Sci ; 35(6): 1677-1682, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-36789828

RESUMEN

Aegle marmelos is cost-effective valuable South Asian tree. The folklore data reported its wide range pharmacological effects. In spite of vast reported work on various parts, the dry ripe fruit extract has not yet been studied for gastric ulcers. Present study is planned to investigate its potential protective effects against ethanol-induced gastric injury in rats. In current study the gastro protective effect of ethanolic crude extract of A. marmelos dried ripe fruit at 200, 400 and 800mg/kg body weight were studied in albino rats. Ranitidine used as standard drug (50mg/kg body weight). Absolute ethanol increase the degree of ulceration (UI) in rats while a significant improvement in the level of inhibition against ulceration was observed in test and standard groups as compare to control. Pre-fed test drug exhibited a significant reduction in the sore area (UI), accelerate % age protection and increased of gastric content in dose dependence manner. Test drug at 800mg/kg dose showed marked deduction in mean UI 3.0, significant increase in protection 83% with pH 7.3 (p<0.01). Standard drug exhibited 3.25 UI, 81% protection with pH 7.1. In conclusion, it was found that dry ripe fruit of A. marmelos possesses a significant anti-ulcer effect in rats.


Asunto(s)
Aegle , Antiulcerosos , Úlcera Gástrica , Aegle/química , Antiulcerosos/efectos adversos , Etanol , Frutas/química , Extractos Vegetales/análisis , Úlcera Gástrica/inducido químicamente , Úlcera Gástrica/tratamiento farmacológico , Úlcera Gástrica/prevención & control , Animales , Ratas
3.
Pain Pract ; 20(7): 761-768, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32462791

RESUMEN

OBJECTIVE: This prospective, open-label, multicenter study evaluated the feasibility of spinal cord stimulation (SCS) therapy programming for chronic low back pain that uses multiple electrical pulsed signals (Differential Target Multiplexed). METHODS: Twenty-five SCS candidates with low back pain equal to or greater than lower limb pain were enrolled at 7 sites in the United States. The subjects evaluated standard and Differential Target Multiplexed programs, each for 4 ± 1 days. A commercially available SCS trial system was used for standard SCS therapy programming. During the trialing of the multiplexed programs, implanted temporary leads were connected to an investigational external trial stimulator system. RESULTS: Twenty subjects concluded the study. The mean baseline numeric pain rating scale (NPRS) score for low back pain was 7.4, with a mean age of 62.4 years and mean pain duration of 18.0 years. Significant relief in back pain was observed for both treatments, with significantly better response with multiplexed programming. At the end of the trial period, subjects reported a reduction in their mean NPRS score from baseline to 4.2 after standard programming and to 2.4 after Differential Target Multiplexed programming. The difference between standard and multiplexed programming was significant. The responder rate for low back pain relief was 50% for standard programming and 80% for Differential Target Multiplexed programming. Eighty-five percent of subjects who evaluated both programming approaches preferred Differential Target Multiplexed SCS. CONCLUSION: In this difficult-to-treat patient population, subjects reported significant reduction in chronic back pain when using multiplexed programming. A randomized clinical trial is needed to confirm the results from this feasibility study.


Asunto(s)
Dolor de Espalda/terapia , Dolor Crónico/terapia , Estimulación de la Médula Espinal/métodos , Anciano , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos
4.
Acta Pol Pharm ; 74(2): 497-504, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29624255

RESUMEN

The development of an optimal microemulsion of lawsone for transdermal delivery was the core objective of the study. Effects of formulation variable including oils, surfactants and co-surfactants on the per- cutaneous delivery of lawsone microemulsion have also been inspected. Pseudotemary phase diagrams with oil, cosurfactant-surfactant mixtures (Smix) were constructed to recognize the microemulsion areas. Microemulsion prepared was of 5%. The in vitro transdermal penetration of microemulsion of lawsone was determined by Franz diffusion cell. These profiles indicated that the absorption and rate of penetration of lawsone microemul- sion was far better than the saturated solution of lawsone. The formulation was characterized for pH, conduc- tivity, viscosity and passed stability tests. A non-irritant formulation to skin was prepared in this way. The out- comes specify that the transdermal drug delivery ability and phase behavior of microemulsion is affected by the type of cosurfactant and surfactant.


Asunto(s)
Portadores de Fármacos , Lawsonia (Planta)/química , Naftoquinonas/química , Extractos Vegetales/química , Administración Cutánea , Adulto , Composición de Medicamentos , Liberación de Fármacos , Estabilidad de Medicamentos , Conductividad Eléctrica , Emulsiones , Excipientes/química , Femenino , Humanos , Concentración de Iones de Hidrógeno , Masculino , Naftoquinonas/administración & dosificación , Naftoquinonas/aislamiento & purificación , Naftoquinonas/metabolismo , Permeabilidad , Fitoterapia , Extractos Vegetales/administración & dosificación , Extractos Vegetales/aislamiento & purificación , Extractos Vegetales/metabolismo , Plantas Medicinales , Piel/metabolismo , Absorción Cutánea , Solubilidad , Tensoactivos/química , Viscosidad , Adulto Joven
5.
J Ayub Med Coll Abbottabad ; 28(1): 94-8, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27323571

RESUMEN

BACKGROUND: Depression is one of the major problems faced by medical students, which have significant adverse effects on their social, academic and occupational functioning. The objectives of the study were to estimate the prevalence of depression and to explore the gender differences and interrelationship between the depression and negative cognitive style among medical students of First year (FY) Last year (LY) MBBS. METHODS: A Cross sectional questionnaire based study was conducted in Ayub medical college Abbottabad; Khyber medical college Peshawar; Bannu medical college; Rawalpindi medical college; Punjab medical college Faisalabad and Allama Iqbal medical college Lahore, Pakistan. Applying stratified sampling technique a battery of questionnaires naming depression screening test, self-report depression scale and cognitive style questionnaire was filed by a sample of 1000 (first and last year) medical students. The data was analysed by SPSS 16. RESULTS: Positive relationship exists between depression and negative cognitive style (r = .57, p < .05) among medical students. Forty one percent male and 61% female students of FY and 58% males and 69% female of LY students exhibited depressive symptoms. Females have higher scores on cognitive style questionnaire t (998) = 3.70, p < .05, and depression t (998) = 4.28, p < .05. The t-test analysis also revealed that FY students were holding more negative cognitive style t (998) = 6.21, p < .05, whereas LY medical students to be more depressed t (998) = 5.43, p < .05. CONCLUSIONS: The study revealed significant distress among medical students. Negative cognitive style positively correlates with depression among medical students. Furthermore, it is noticed that among female students the prevalence of depressive symptoms and negative cognitive style was higher. Moreover, it is concluded that the prevalence of depression in LY and negative cognitive styles among FY was higher respectively. Students should be provided proper counselling to avoid and cope with faulty thought patterns leading to depression. Keywords: negative cognitive style, depression, gender.


Asunto(s)
Cognición , Depresión/epidemiología , Negativismo , Estudiantes de Medicina/psicología , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Pakistán/epidemiología , Factores Sexuales , Adulto Joven
6.
J Ayub Med Coll Abbottabad ; 28(2): 348-352, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-28718550

RESUMEN

BACKGROUND: It is believed that the study of personality has the potentials to enhance our prognostic abilities and can better to expose the etiology of mental illness through the relationship of revealed mechanisms. The focus of this study was to investigate and compare the habitual patterns of behavior, thought and emotions of upper and lower limb physically disabled students in terms of personality traits. METHODS: This cross sectional study consisted of 100 upper limbs and lower limbs disabled students taken from Kingston school Inclusive Education System Abottabad, Mashal special education system Haripur, Syed Ahmed Shaheed special education center Abottabad, Al-Munir Foundation Mansehra and Hera Special Education System Haripur and 100 normal students taken from Islamic International School Abottabad, Falcon Public School Haripur, Iqra Academy Mansehra and Alhamd International School Haripur of Hazara Division by purposive sampling technique. This study was conducted during the month of June 2013 to May 2014. Goldberg five big personality scale was used for measuring personality traits of physically disabled and normal students. RESULTS: The significant difference of personality traits scores between physically disabled students (M = 139.2, SD=12.0) and normal students (M=184.5, SD=13.2), t (198) =25.3, p<.05 was observed. CONCLUSIONS: Normal students have high scores as compared to physically disabled students on big five traits, i.e., Extraversion, Agreeableness, Conscientiousness, Emotional Stability and Openness to Experience.


Asunto(s)
Personas con Discapacidad/psicología , Personas con Discapacidad/estadística & datos numéricos , Extremidad Inferior/fisiopatología , Personalidad/fisiología , Extremidad Superior/fisiopatología , Adolescente , Adulto , Estudios Transversales , Femenino , Humanos , Masculino , Pakistán/epidemiología , Adulto Joven
7.
J Spinal Disord Tech ; 28(6): E343-6, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23563341

RESUMEN

STUDY DESIGN: A retrospective cohort study was performed to analyze the effect of a specifically timed glove change on infection rates in lumbar spinal fusion. OBJECTIVES: Postoperative infection is a frequent and taxing complication following posterior lumbar spine fusion with instrumentation. This procedure is associated with infection rates up to 9%. The most common organism responsible for infection is Staphylococcus aureus which, along with many of the other common causative organisms, is often part human skin flora. This implicates the surgeon's gloves as the mode of transfer for these organisms from the patient's skin to the wound. The authors conducted a retrospective study to determine if a simple glove change before handling instrumentation could significantly reduce the rate of postoperative infection for this procedure. MATERIALS AND METHODS: A total of 389 patients requiring lumbar spine fusion were enrolled retrospectively and divided into 2 groups: a control group of 179 patients treated with standard protocol for the procedure (group A) and a treatment group of 210 patients in whom, after initially double gloving, the outer pair of gloves was removed before handling the instrumentation. Infection rates were compared up to 1 year postoperatively. RESULTS: There was a statistically significant reduction of infection rate from 3.35% in group A (control) to 0.48% in group B (P=0.0369). CONCLUSION: This study shows that the removal of an outer pair of gloves before handling instrumentation may be a simple, cost-effective, and practical way to reduce the burden of postoperative infection following lumbar spinal fusion.


Asunto(s)
Guantes Quirúrgicos , Fusión Vertebral/métodos , Infección de la Herida Quirúrgica/prevención & control , Estudios de Cohortes , Humanos , Procedimientos Neuroquirúrgicos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/prevención & control , Estudios Retrospectivos , Fusión Vertebral/efectos adversos , Infecciones Estafilocócicas/prevención & control , Instrumentos Quirúrgicos
10.
PLoS One ; 19(3): e0299350, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38427638

RESUMEN

Agricultural Remote Sensing has the potential to enhance agricultural monitoring in smallholder economies to mitigate losses. However, its widespread adoption faces challenges, such as diminishing farm sizes, lack of reliable data-sets and high cost related to commercial satellite imagery. This research focuses on opportunities, practices and novel approaches for effective utilization of remote sensing in agriculture applications for smallholder economies. The work entails insights from experiments using datasets representative of major crops during different growing seasons. We propose an optimized solution for addressing challenges associated with remote sensing-based crop mapping in smallholder agriculture farms. Open source tools and data are used for inter and intra-sensor image registration, with a root mean square error of 0.3 or less. We also propose and emphasize on the use of delineated vegetation parcels through Segment Anything Model for Geospatial (SAM-GEOs). Furthermore a Bidirectional-Long Short-Term Memory-based (Bi-LSTM) deep learning model is developed and trained for crop classification, achieving results with accuracy of more than 94% and 96% for validation sets of two data sets collected in the field, during 2 growing seasons.


Asunto(s)
Agricultura , Imágenes Satelitales , Agricultura/métodos , Granjas , Estaciones del Año , Productos Agrícolas
11.
PeerJ Comput Sci ; 10: e1894, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38660216

RESUMEN

Heart failure is a complex cardiovascular condition characterized by the heart's inability to pump blood effectively, leading to a cascade of physiological changes. Predicting survival in heart failure patients is crucial for optimizing patient care and resource allocation. This research aims to develop a robust survival prediction model for heart failure patients using advanced machine learning techniques. We analyzed data from 299 hospitalized heart failure patients, addressing the issue of imbalanced data with the Synthetic Minority Oversampling (SMOTE) method. Additionally, we proposed a novel transfer learning-based feature engineering approach that generates a new probabilistic feature set from patient data using ensemble trees. Nine fine-tuned machine learning models are built and compared to evaluate performance in patient survival prediction. Our novel transfer learning mechanism applied to the random forest model outperformed other models and state-of-the-art studies, achieving a remarkable accuracy of 0.975. All models underwent evaluation using 10-fold cross-validation and tuning through hyperparameter optimization. The findings of this study have the potential to advance the field of cardiovascular medicine by providing more accurate and personalized prognostic assessments for individuals with heart failure.

12.
Nat Prod Res ; : 1-11, 2023 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-38018814

RESUMEN

Anti-hyperlipidaemic effect of chloroform fraction of aerial parts of Zygophyllum indicum (Fagonia indica Burm.f.) was studied in rats. Adult Wistar albino rats were distributed into five groups. Rats of all groups except group I were given an intraperitoneal injection (Triton X-100) to induce hyperlipidaemia. Groups (I and II) served as normal and hyperlipidaemic control groups respectively. Group III and group IV were administered with 250 and 500 mg/kg chloroform fraction of the plant respectively after 18 h of inducing hyperlipidaemia. Group V was given 10 mg/kg of the standard atorvastatin. Chloroform fraction had significant (p < 0.05) hypolipidaemic effects on lipid profile and biochemical parameters with a protective effect on the liver in comparison to group II. F. indica with hypolipidaemic effect is useful in the management of hyperlipidaemia. Chloroform fraction with its constituents can be used as an antihyperlipidaemic supplement in developing countries for the development of novel therapeutic agents.

13.
PLoS One ; 18(4): e0284791, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37098024

RESUMEN

An electrocardiograph (ECG) is widely used in diagnosis and prediction of cardiovascular diseases (CVDs). The traditional ECG classification methods have complex signal processing phases that leads to expensive designs. This paper provides a deep learning (DL) based system that employs the convolutional neural networks (CNNs) for classification of ECG signals present in PhysioNet MIT-BIH Arrhythmia database. The proposed system implements 1-D convolutional deep residual neural network (ResNet) model that performs feature extraction by directly using the input heartbeats. We have used synthetic minority oversampling technique (SMOTE) that process class-imbalance problem in the training dataset and effectively classifies the five heartbeat types in the test dataset. The classifier's performance is evaluated with ten-fold cross validation (CV) using accuracy, precision, sensitivity, F1-score, and kappa. We have obtained an average accuracy of 98.63%, precision of 92.86%, sensitivity of 92.41%, and specificity of 99.06%. The average F1-score and Kappa obtained were 92.63% and 95.5% respectively. The study shows that proposed ResNet performs well with deep layers compared to other 1-D CNNs.


Asunto(s)
Algoritmos , Enfermedades Cardiovasculares , Humanos , Redes Neurales de la Computación , Arritmias Cardíacas/diagnóstico , Electrocardiografía , Procesamiento de Señales Asistido por Computador
14.
Gene ; 852: 147065, 2023 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-36435508

RESUMEN

Alternative splicing (AS) and alternative polyadenylation (APA) are common mechanisms in eukaryotes to increase the complexity of transcriptomes and subsequently proteomes. Analysis of long reads transcriptomics data can result in the discovery of novel transcripts, splice sites, AS or APA events. Gossypium arboreum is an important cultivated cotton species and a putative contributor of the A sub-genome to the modern tetraploid cotton; and inherently tolerant to several biotic and abiotic stresses. Specifically, its variety 'FDH228' is considered to be an important resistance source. In this study, we sequenced the G. arboreum (var. FDH228) transcriptome using PacBio IsoSeq and illumina short read sequencing under three different conditions i.e. untreated/healthy, treated with biotic stress through whitefly infestation, and treated with abiotic stress via water deprivation, for the discovery and surveying of canonical and non-canonical AS, APA and transcript fusion events. We were able to obtain 15,419 unique transcripts from all samples representing 11,343 genes, out of which 10,832 were annotated and 520 were novel with respect to the published reference genome. These transcripts were grouped into different structural categories including 60 Antisense, 11,959 having a full-splice match, 999 with incomplete-splice match, 30 fusion transcripts, 177 genic, 479 intergenic, 771 novels in the catalog, and 944 Novel but not found in the catalog. Subsequently, randomly selected candidate transcripts were experimentally validated using qRT-PCR. Our comprehensive identification of canonical and non-canonical splicing events, and novel and fusion transcripts aids in the understanding of the resistance mechanisms for this specific germplasm.


Asunto(s)
Hemípteros , Transcriptoma , Animales , Transcriptoma/genética , Gossypium/genética , Hemípteros/genética , Sequías , Perfilación de la Expresión Génica , Regulación de la Expresión Génica de las Plantas
15.
Heliyon ; 9(8): e18547, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37576202

RESUMEN

There are numerous scenarios where the photographer is in difficulty and unable to capture or shoot video as required. This could be due to several factors such as limited space, decreased visibility, and an obstacle in the way. Therefore, this project implements the idea to capture and shoot video of the desired subject through an automatically controlled robotic camera with no need for a photographic bloke. The system comprises functions such as detection, tracking, live streaming, and video/audio recording along with the features of Radio-Frequency-Identification (RFID). Therefore, this robotic camera will detect the desired subject, track and focus it with the help of its position driven through movable motors sensing the RFID tag in case the object is non-stationary. The video/audio will be recorded on a computer along with the live streaming available on an Android-based device. The Viola-Jones algorithm of the image processing technique is used to detect the particular subject features and C for accessing the movable camera protocols. The RFID transmitter and receiver are used to sense the RFID card and serve the purpose to track the subject using the algorithms of image processing, with the advantage of ignoring other obstacles between the camera and the detected subject. Thus, adding a novel functionality to the existing systems, that lacks the feature of focusing the camera on the subject, when an obstacle is detected in between. The live streaming is achieved wirelessly through an open-source platform X-operating system, Apache, MySQL, Php, Perl (XAMPP). The idea is verified through concluded arrangements in self-made scenarios in response to the speed, distance, light, and background noise of the detected subject, which delivered encouraging results. Therefore, the designed system can be used for live conferences, seminars, and other multimedia-required arrangements.

16.
Mol Biotechnol ; 65(7): 1052-1061, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36437439

RESUMEN

Virus-induced gene silencing (VIGS) by deploying viral-based vectors such as tobacco rattle virus (TRV) is a homology-based gene silencing technique in post-transcriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) to validate the function of particular genes. The study presented here showed the induction of DNA methylation in the promoter regions of three phenotypic marker genes in different cotton accessions, including two endogenous genes such as phytoene desaturase (PDS) and phytoene synthase (PSY), and an exogenous gene, such as green fluorescent protein (GFP). First, DNA methylation was established in transgenic GFP cotton where methylation persisted up to S3 generation. Afterward, the promoter of PSY was targeted following the same conditions. Significant silencing of PSY was observed and methylation of the promoter was found up to S2 generation in red leaf cotton as detected in GFP cotton. Silencing of PDS resulted in a photobleaching phenotype; interestingly, the strength of this phenotype was diverse within the plants and was not observed in the next generation. Bisulfite sequencing results showed methylation percentage of the cytosine residues was high at CG and CHG sites of the targeted promoter sequences in the silenced plants. The findings of this paper suggest that TRV-based vector system can be used to monitor DNA methylation for both exogenous and endogenous gene levels in cotton and offer a very useful tool for plant epigenetic modification.


Asunto(s)
Silenciador del Gen , Virus de Plantas , Proteínas Fluorescentes Verdes/genética , Metilación de ADN , Virus de Plantas/genética , Regiones Promotoras Genéticas , Regulación de la Expresión Génica de las Plantas , Vectores Genéticos/genética , Nicotiana/genética
17.
Micromachines (Basel) ; 14(6)2023 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-37374701

RESUMEN

Optical switching is an essential part of photonic integrated circuits and the focus of research at the moment. In this research, an optical switch design working on the phenomenon of guided-mode resonances in a 3D photonic-crystal-based structure is reported. The optical-switching mechanism is studied in a dielectric slab-waveguide-based structure operating in the near-infrared range in a telecom window of 1.55 µm. The mechanism is investigated via the interference of two signals, i.e., the data signal and the control signal. The data signal is coupled into the optical structure and filtered utilizing guided-mode resonance, whereas the control signal is index-guided in the optical structure. The amplification or de-amplification of the data signal is controlled by tuning the spectral properties of the optical sources and structural parameters of the device. The parameters are optimized first using a single-cell model with periodic boundary conditions and later in a finite 3D-FDTD model of the device. The numerical design is computed in an open-source Finite Difference Time Domain simulation platform. Optical amplification in the range of 13.75% is achieved in the data signal with a decrease in the linewidth up to 0.0079 µm, achieving a quality factor of 114.58. The proposed device presents great potential in the field of photonic integrated circuits, biomedical technology, and programmable photonics.

18.
Materials (Basel) ; 16(7)2023 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-37048923

RESUMEN

In this paper a perfect absorber with a photonic crystal cavity (PhC-cavity) is numerically investigated for carbon dioxide (CO2) gas sensing application. Metallic structures in the form of silver are introduced for harnessing plasmonic effects to achieve perfect absorption. The sensor comprises a PhC-cavity, silver (Ag) stripes, and a host functional material-Polyhexamethylene biguanide polymer-deposited on the surface of the sensor. The PhC-cavity is implemented within the middle of the cell, helping to penetrate the EM waves into the sublayers of the structure. Therefore, corresponding to the concentration of the CO2 gas, as it increases, the refractive index of the host material decreases, causing a blue shift in the resonant wavelength and vice versa of the device. The sensor is used for the detection of 0-524 parts per million (ppm) concentration of the CO2 gas, with a maximum sensitivity of 17.32 pm (pico meter)/ppm achieved for a concentration of 366 ppm with a figure of merit (FOM) of 2.9 RIU-1. The four-layer device presents a straightforward and compact design that can be adopted in various sensing applications by using suitable host functional materials.

19.
Heliyon ; 9(11): e21488, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-38034628

RESUMEN

The heliostat field layout in a central receiver solar thermal power plant has significant optical losses that can ultimately affect the overall output power of the plant. In this paper, an optimized heliostat field layout based on annual efficiency and power of 50 MW for the local coordinates of Quetta, Pakistan, is proposed. The performance of two different heliostat field layouts such as radial staggered and Fermat's spiral distribution are evaluated and different design points in a year are considered for the analysis. The field layouts are then optimized using a rejection sampling based Genetic Algorithm (GA). It considers the output power and mean overall efficiency for vernal equinox, summer solstice, autumnal equinox, and winter solstice as objective functions. The GA optimizes the heliostat field parameters, namely, security distance (DS), tower height (TH), heliostat width to length ratio (WR), and the length of heliostats (LH). The study system was developed in MATLAB for validation. It was observed that for the radial staggered layout, the number of heliostats decreased by 364 and the efficiency was improved by 8.52 % using GA optimization relative to unoptimized results field layout. The annual efficiency for Fermat's spiral configuration was improved by 14.62 % and correspondingly, the number of heliostats decreased by 434.

20.
Big Data ; 10(1): 65-80, 2022 02.
Artículo en Inglés | MEDLINE | ID: mdl-34227852

RESUMEN

In image registration, the search space used to compute the optimal transformation between the images depends on the group of pixels in the vicinity. Favorable results can be achieved by significantly increasing the number of neighboring pixels in the search space; however, this strategy increases the computational load, thus making it challenging to realize the most desirable solution in a reasonable amount of time. To address the mentioned problem, the genetic algorithm is used to find the optimum solution and the solution lies in finding the best chromosomes. In rigid image registration problem, chromosomes contain a set of three parameters, x-translation, y-translation, and rotation. The genetic algorithm iteratively improves chromosomes from generation to generation and selects the best one having the best fittest value. Chromosomes with high fitness value are the ones with an optimal solution where the template image best aligns reference image. Fitness function in the genetic algorithm for image registration problem uses similarity measure index measure to find the amount of similarity between two images. The best fittest value is the one with a high similarity measure that shows the best-aligned template and reference image. Here we used the structural similarity index measure in fitness function that helps in evaluating the best chromosome, even for the compressed images with low quality, intensity nonuniformity (INU), and noise degradation. Building on the genetic algorithm, we propose a novel approach called multistage forward path regenerative genetic algorithm (MFRGA), abbreviated as MFRGA, with reducing search space at each stage. Compared with the single stage of genetic algorithm, our approach proved to be more reliable and accurate in terms of finding true rigid image transformation for alignment. At each increasing stage of MFRGA, results are computed with decreasing search space and increasing precision levels. Moreover, to prove the robustness of our algorithm, we utilized compressed images of brain magnetic resonant imaging that vary in compression qualities ranging from 10 to 100. Furthermore, we added noise levels of 1%, 3%, 5%, 7%, and 9% with an INU of 20% and 40%, respectively, provided by the online BrainWeb simulator. We achieved the monomodal rigid image registration that proves to be successful using MFRGA, even when the noise is critical, the compression quality is the least, and the intensity is nonuniform.


Asunto(s)
Algoritmos , Encéfalo , Encéfalo/diagnóstico por imagen , Fenómenos Magnéticos
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