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The aim of the present work is to use the latest achievements of nanotechnology (atomic layer deposition, ALD) in the field of food packaging to prevent biofilm formation by food-associated bacteria. Some potential applications of nanotechnology in the food packaging industry are studied in the manuscript, in the field of antibacterial materials for food packaging. The ALD technique was used to synthesize vanadium (V)-doped TiO2 thin nanofilm on commercially available polypropylene (PP) food container to enhance an antibacterial activity for potential use in food packaging, to reduce spoilage, thereby, prolonging the food shelf- life. To better understand the ability and effectiveness of the antimicrobial packaging material of V-doped TiO2, to prevent the biofilm formation by dairy-associated pathogenic bacteria, the coated and uncoated PP containers with a fresh raw cow's milk were tested. We have illustrated the effectiveness of ALD Al2O3 + TiVOx nanocoating against populations of milk-borne pathogenic bacteria.
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The purpose of this study was to evaluate the financial performances of the publicly held healthcare companies in crisis periods in Türkiye. The 2018 economic crisis and the COVID-19 pandemic crisis were included in the study as the crisis periods. We collected the financial data of the publicly held healthcare companies and calculated three liquidity, three turnover, three leverage and three profitability ratios through ratio analysis to use as financial performance indicators. We then conducted Wilcoxon signed-rank tests and we performed separate analyses for the 2018 economic crisis and the COVID-19 pandemic crisis. The results of the analyses showed that there were no statistically significant differences between the publicly held healthcare companies' liquidity, turnover, leverage, profitability ratios and thus their financial performances before the crises and after the crises. While the results are reassuring and give valuable insights to managers and policy makers to determine the areas that needs to be strengthened to be better prepared for possible future crises, our sample was limited. Therefore, this study presents an exploratory foundation for future studies which are needed to make a case for financial stability for the publicly held healthcare companies before and after the crisis periods.
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BACKGROUND: Healthcare-associated infections (HAIs) increase morbidity, mortality and costs. The overall prevalence of HAIs is greater in low- and middle-income countries due to poor resources and infrastructure, with the incidence of HAIs greater among neonates and children. There is a need to understand the current situation in Pakistan including key drivers to improve future care. METHODS: Point prevalence survey (PPS) of HAIs in the children's wards of 19 public sector secondary- and tertiary-care hospitals of Pakistan and associated key drivers. RESULTS: A total of 1147 children were included in the PPS. 35.7% were neonates with 32.8% aged >1-5 years. 35.2% were admitted to the intensive care units (ICUs). Peripheral, central venous and urinary catheters were present in 48%, 2.9% and 5.6% of the patients, respectively. A total of 161 HAIs from various pathogens were observed in 153 cases, giving a prevalence of 13.3%. The majority of HAIs were caused by Staphylococcus aureus (31.7%) followed by Klebsiella pneumoniae (22.9%) and Escherichia coli (17.4%). Bloodstream infections were identified in 42 cases followed by lower-respiratory-tract infections in 35. Increased length of hospital stays and being admitted to the ICU, 'rapidly fatal' patients under the McCabe and Jackson criteria, central and peripheral catheterization, and invasive mechanical ventilation were, associated with higher HAIs (P<0.001). 99.7% of HAI patients fully recovered and were discharged from the hospital. CONCLUSION: There is a high prevalence of HAIs among neonates and children admitted to health facilities in Pakistan. Infection prevention and control measures should be implemented to help prevent future HAIs.
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Infección Hospitalaria , Recién Nacido , Humanos , Niño , Prevalencia , Pakistán/epidemiología , Infección Hospitalaria/epidemiología , Infección Hospitalaria/prevención & control , Hospitales , Atención a la SaludRESUMEN
Introduction: The metal-organic frameworks (MOF) have shown fascinating possibilities in biomedical applications, and designing a drug delivery system (DDS) based on the MOF is important. This work aimed at developing a suitable DDS based on Denosumab-loaded Metal Organic Framework/Magnesium (DSB@MOF (Mg)) for attenuating osteoarthritis. Materials and Methods: The MOF (Mg) (Mg3(BPT)2(H2O)4) was synthesized using a sonochemical protocol. The efficiency of MOF (Mg) as a DDS was evaluated by loading and releasing DSB as a drug. In addition, the performance of MOF (Mg) was evaluated by releasing Mg ions for bone formation. The MOF (Mg) and DSB@MOF (Mg) cytotoxicity towards the MG63 cells were explored by MTT assay. Results: MOF (Mg) characterized by using XRD, SEM, EDX, TGA, and BET. Drug loading, and releasing experiments proved that DSB was loaded on the MOF (Mg) and approximately 72% DSB was released from it after 8 h. The characterization techniques showed that MOF (Mg) was successfully synthesized with good crystal structure and thermal stability. The result of BET showed that MOF (Mg) had high surface areas and pore volume. This is the reason why its 25.73% DSB was loaded in the subsequent drug-loading experiment. Drug release and ion release experiments indicated DSB@MOF (Mg) had a good controlled release of DSB and Mg ions in solution. Cytotoxicity assay confirmed that the optimum dose of it had excellent biocompatibility and could stimulate the proliferation of MG63 cells as time went on. Conclusion: Due to the high loading amount of DSB and releasing time, DSB@MOF (Mg) can be promising as a suitable candidate for relieving bone pain caused by osteoporosis, with ossification-reinforcing functions.
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Turbulence is a complex phenomenon that has a chaotic nature with multiple spatio-temporal scales, making predictions of turbulent flows a challenging topic. Nowadays, an abundance of high-fidelity databases can be generated by experimental measurements and numerical simulations, but obtaining such accurate data in full-scale applications is currently not possible. This motivates utilising deep learning on subsets of the available data to reduce the required cost of reconstructing the full flow in such full-scale applications. Here, we develop a generative-adversarial-network (GAN)-based model to reconstruct the three-dimensional velocity fields from flow data represented by a cross-plane of unpaired two-dimensional velocity observations. The model could successfully reconstruct the flow fields with accurate flow structures, statistics and spectra. The results indicate that our model can be successfully utilised for reconstructing three-dimensional flows from two-dimensional experimental measurements. Consequently, a remarkable reduction in the complexity of the experimental setup and the storage cost can be achieved.
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To investigate how plyometric exercise (PLYO-Ex) affects mechanics and morphometrics of the plantar flexor musculotendinous unit in children with unilateral cerebral palsy, 38 participants (aged 10-16 years) were allocated at random to either the PLYO-Ex group (n = 19; received 24 sessions of plyometric muscle loading, conducted 2 times a week for 3 months in succession) or the control group (n = 19; underwent traditional physical therapy for the same frequency and duration). Measurements were taken pre- and post-intervention. Standard ultrasound imaging was applied to evaluate morphometrics of the gastrocnemius muscle and Achilles tendon unit and an isokinetic dynamometer was used to evaluate maximum voluntary isometric plantar flexors contraction (IVCmax). With controlling for pre-treatment values, significant post-treatment changes favoring the PLYO-Ex group were observed for morphological (tendon (p = 0.003, η2p = 0.23) length; belly length (p = 0.001, η2p = 0.27); tendon thickness (p = 0.035, η2p = 0.35); muscle thickness (p = 0.013, η2p = 0.17); fascicle length (p = 0.009, η2p = 0.18); pennation angle (p = 0.015, η2p = 0.16)) and mechanical and material properties (IVCmax (p = 0.009, η2p = 0.18); tendon's elongation (p = 0.012, η2p = 0.17), stiffness (p = 0.027, η2p = 0.13); stress (p = 0.006, η2p = 0.20); strain (p = 0.004, η2p = 0.21)). In conclusion, plyometric exercise induces significant adaptations within the musculotendinous unit of the plantar flexors in children with unilateral cerebral palsy. These adaptations could improve muscular efficiency and consequently optimize physical/functional performance.
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A new approach has been developed for environmentally friendly C-C cross-coupling reactions using bi-functional Pd(ii)-salen complex-embedded cellulose filter paper (FP@Si-PdII-Salen-[IM]OH). A Pd(ii)-salen complex bearing imidazolium [OH]-moieties was covalently embedded into a plain filter paper, then used as an efficient portable catalyst for the Heck, Suzuki, and Sonogashira cross-coupling reactions under environmentally friendly conditions via the filtration method. The catalytic filter paper properties were studied by EDX, XPS, TGA, ATR, XRD, and FESEM analyses. The reactions were catalyzed during reactants' filtration over the catalytic filter paper. The modified filter paper was set up over a funnel and the reactants were passed through the catalytic filter paper several times. The effect of reaction parameters including loading of Pd(ii)-salen complex, temperature, solvent, and contact time were carefully studied and also the optimal model of conditions was presented by the design expert software. High to excellent yields were obtained for all C-C coupling types with 5 to 8 filtration times. Under optimal conditions, all coupling reactions showed high selectivity and efficiency. Another advantage of the modified filter paper was its stability and reusability for several times with preservation of catalytic activity and swellability.
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BACKGROUND: Chest High-Resolution Computed Tomography (HRCT) is mandatory for patients with confirmed Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and a high Respiratory Rate (RR) because sublobar consolidation is the likely pathological pattern in addition to Ground Glass Opacities (GGOs). OBJECTIVE: The present study determined the correlation between the percentage extent of typical pulmonary lesions on HRCT, as a representation of severity, and the RR and peripheral oxygen saturation level (SpO2), as measured through pulse oximetry, in patients with Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)-confirmed primary (noncomplicated) SARS-CoV-2 pneumonia. METHODS: The present retrospective study was conducted in 332 adult patients who presented with dyspnea and hypoxemia and were admitted to Prince Mohammed bin Abdulaziz Hospital, Riyadh, Saudi Arabia between May 15, 2020 and December 15, 2020. All the patients underwent chest HRCT. Of the total, 198 patients with primary noncomplicated SARS-CoV-2 pneumonia were finally selected based on the typical chest HRCT patterns. The main CT patterns, GGO and sublobar consolidation, were individually quantified as a percentage of the total pulmonary involvement through algebraic summation of the percentage of the 19 pulmonary segments affected. Additionally, the statistical correlation strength between the total percentage pulmonary involvement and the age, initial RR, and percentage SpO2 of the patients was determined. RESULTS: The mean ± Standard Deviation (SD) age of the 198 patients was 48.9 ± 11.4 years. GGO magnitude alone exhibited a significant weak positive correlation with patients' age (r = 0.2; p = 0.04). Sublobar consolidation extent exhibited a relatively stronger positive correlation with RR than GGO magnitude (r = 0.23; p = 0.002). A relatively stronger negative correlation was observed between the GGO extent and SpO2 (r = - 0.38; p = 0.002) than that between sublobar consolidation and SpO2 (r = - 0.2; p = 0.04). An increase in the correlation strength was demonstrated with increased case segregation with GGO extent (r = - 0.34; p = 0.01). CONCLUSION: The correlation between the magnitudes of typical pulmonary lesion patterns, particularly GGO, which exhibited an incremental correlation pattern on chest HRCT, and the SpO2 percentage, may allow the establishment of an artificial intelligence program to differentiate primary SARS-CoV-2 pneumonia from other complications and associated pathology influencing SpO2.
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COVID-19 , SARS-CoV-2 , Humanos , Adulto , Persona de Mediana Edad , COVID-19/diagnóstico por imagen , Estudios Retrospectivos , Inteligencia Artificial , Saturación de Oxígeno , Tomografía Computarizada por Rayos X/métodosRESUMEN
PURPOSE: This study aimed to determine the radioprotective effect of N-acetylcysteine (NAC) on the radiation-induced oxidative stress (OS) in the rats' brainstem. MATERIALS AND METHODS: Eighty rats in four identical groups, including vehicle control (VC), irradiation alone (RAD), irradiation with 1 g/kg of NAC treatment (RAN), and NAC treatment without radiation (NAC) were used. Whole-brain irradiation was performed with a single dose of 25 Gy. The rats received the treatments via intraperitoneal (IP) injection 1 h before the irradiation process. Nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), total antioxidant capacity (TAC), and glutathione peroxidase (GPx) were measured in the rats' brainstem and compared between the groups. Furthermore, the pathological study was performed to assess tissue damage after 24 h, 72 h, and 5 days of irradiation. RESULTS: The levels of NO and MDA in the brainstem tissue for the RAD group were 60.37 ± 3.35 µmol/L and 45.10 ± 2.48 µM, respectively, which were higher than those of VC group (NO: 30.41 ± 1.83 µmol/L; MDA: 31.02 ± 1.71 µM). The level of SOD, CAT, TAC, and GPx declined in the RAD compared to the VC group. Pre-treatment with NAC decreased the level of NO and MDA and also enhanced the antioxidant activities. The greatest pathological changes in the rats' brainstems were seen in RAD animals compared to the VC group at 24 h, 72 h, and 5 days. Furthermore, the pathological changes were not observed in the NAC group in all the assessed times. CONCLUSION: Based on the results, NAC can decrease the irradiation-induced oxidative stress and pathology damages in the rats' brainstem. It can be concluded that NAC can be an appropriate radioprotection candidate for the human brainstem.
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Acetilcisteína , Antioxidantes , Tronco Encefálico , Protectores contra Radiación , Acetilcisteína/farmacología , Animales , Antioxidantes/metabolismo , Tronco Encefálico/metabolismo , Tronco Encefálico/efectos de la radiación , Glutatión Peroxidasa/metabolismo , Malondialdehído/metabolismo , Protectores contra Radiación/farmacología , Ratas , Superóxido Dismutasa/metabolismo , Rayos X/efectos adversosRESUMEN
A compartment fire (a fire in a room or building) creates temperature gradients and inhomogeneous time-varying temperature, density, and flow fields. This work compared experimental measurements of the room acoustic impulse/frequency response in a room with a fire to numerically modeled responses. The fire is modeled using a Fire Dynamics Simulator (FDS). Acoustic modeling was performed using the temperature field computed by FDS. Room acoustics were modeled using two-dimensional ray and finite element modeling. A three-dimensional model was used to simulate an open flame. COMSOLTM Multiphysics was used for finite element acoustic modeling and BELLHOPTM for ray trace acoustics modeling. The results show that the fire causes wave-fronts to arrive earlier (due to the higher sound speed) and with more variation in the delay times (due to the sound speed perturbations). The resonance frequencies of low-frequency modes were shifted upwards. Model results are compared with data and show good agreement in observed trends.
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BACKGROUND: Pain is one of the most feared consequences of cancer for patients and their families. Many barriers may hinder optimal pain management. AIM: Examine the effect of remote-based monitoring and education program on cancer pain management, patient-related barriers, and level of adherence to pain medication. METHODS: A sample of 134 patients was assigned to two groups; 68 in the intervention group and 66 in the control. The intervention group received three educational sessions by telephone. Both groups completed questionnaires at baseline and one month after the initial visit. RESULTS: Significant differences were found between the groups in the levels of pain right now (p = .030), pain at its least (p = .016), and in the percentage of achieved pain relief (p = .048). Moreover, the intervention group experienced lower levels of interference with their general activity (p = < .001), mood (p = .011), and normal work (p = .004) post-intervention. The Attitudinal Barriers differences were statistically significant in the total mean (p = < .001), and the subscales of physiological effects (p = < .001), fatalism (p = < .001), communication (p = < .001), harmful effects (p = < .001). Participants in the intervention group exhibited higher adherence levels (p = .001). CONCLUSIONS: Patients suffering from cancer-related pain can benefit from remote-based monitoring and education programs to improve pain management outcomes, overcome barriers, and increase adherence. Further research is needed to investigate the different available educational methods and long-term effects.
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Dolor en Cáncer , Neoplasias , Humanos , Manejo del Dolor , Clínicas de Dolor , Pacientes Ambulatorios , Dolor , Dolor en Cáncer/tratamiento farmacológico , Neoplasias/complicacionesRESUMEN
BACKGROUND: High-grade serous ovarian cancer (HGSOC) is the most common subtype of ovarian cancer and is associated with high mortality rates. Surgical outcome is one of the most important prognostic factors. There are no valid biomarkers to identify which patients may benefit from a primary debulking approach. OBJECTIVE: Our study aimed to discover and validate a predictive panel for surgical outcome of residual tumor mass after first-line debulking surgery. STUDY DESIGN: Firstly, "In silico" analysis of publicly available datasets identified 200 genes as predictors for surgical outcome. The top selected genes were then validated using the novel Nanostring method, which was applied for the first time for this particular research objective. 225 primary ovarian cancer patients with well annotated clinical data and a complete debulking rate of 60% were compiled for a clinical cohort. The 14 best rated genes were then validated through the cohort, using immunohistochemistry testing. Lastly, we used our biomarker expression data to predict the presence of miliary carcinomatosis patterns. RESULTS: The Nanostring analysis identified 37 genes differentially expressed between optimal and suboptimal debulked patients (p < 0.05). The immunohistochemistry validated the top 14 genes, reaching an AUC Ø0.650. The analysis for the prediction of miliary carcinomatosis patterns reached an AUC of Ø0.797. CONCLUSION: The tissue-based biomarkers in our analysis could not reliably predict post-operative residual tumor. Patient and non-patient-associated co-factors, surgical skills, and center experience remain the main determining factors when considering the surgical outcome at primary debulking in high-grade serous ovarian cancer patients.
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Cistadenocarcinoma Seroso , Neoplasias Ováricas , Neoplasias Peritoneales , Bancos de Muestras Biológicas , Biomarcadores , Carcinoma Epitelial de Ovario , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/cirugía , Femenino , Humanos , Neoplasia Residual , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Neoplasias Ováricas/cirugía , Estudios Prospectivos , Resultado del TratamientoRESUMEN
Experiences in family, school, and social life during childhood are associated with gender roles and occupational choice capability. This study examines how competent individuals are in occupational choice capability and the relationships of childhood experiences and gender roles with their competencies in occupational choice capability. The research is composed of 805 individuals aged 18 and older, who reside in Turkey. In the research, we used the Personal Information Form, Childhood Experiences Scale, Gender Roles Attitude Scale, and The Scale of Occupational Choice Capability. The SPSS 25 program and PROCESS-Macro were used to analyze the variables. The relationship between the scales was investigated using Pearson correlation analysis and multiple regression analysis. According to the findings we obtained, individuals' family and school life were positively correlated with their career choices, and family function sexism harmed their choice of profession. We also found gender roles had a mediating role in the relationship between school life and career choice.
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This study aims to study the discharging process to verify the influence of geometry modifications and heat transfer flow (HTF) patterns on the performance of a vertical triplex-tube latent heat container. The phase change material (PCM) is included in the middle tube, where the geometry is modified using single or multi-internal frustum tubes instead of straight tubes to enhance the discharging rate. The effects of the HTF flow direction, which is considered by the gravity and opposite-gravity directions, are also examined in four different cases. For the optimal geometry, three scenarios are proposed, i.e., employing a frustum tube for the middle tube, for the inner tube, and at last for both the inner and middle tubes. The effects of various gap widths in the modified geometries are investigated. The results show the advantages of using frustum tubes in increasing the discharging rate and reducing the solidification time compared with that of the straight tube unit due to the higher natural convection effect by proper utilization of frustum tubes. The study of the HTF pattern shows that where the HTF direction in both the inner and outer tubes are in the gravity direction, the maximum discharging rate can be achieved. For the best configuration, the discharge time is reduced negligibly compared with that for the system with straight tubes which depends on the dimensions of the PCM domain.
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A reductive filter paper for selective nitro reduction has been prepared by modification of a pristine cellulose filter paper by Pd/C nanoparticles, as a portable catalyst. The reaction was performed in two different set-ups including (i) filtration and (ii) sealed systems, in the presence of ammonium formate and ex situ generated hydrogen gas reducing agents, respectively. In the sealed system in the presence of H2 gas, the halogenated nitroarenes were completely reduced, while in the filtration system, different derivatives of the nitroarenes were selectively reduced to aryl amines. In both systems, the reduction of nitroarenes to aryl amines was performed with high efficiency and selectivity, comparable to a heterogeneous system. Reaction parameters were comprehensively designed using Design Expert software and then studied. The properties of the catalytic filter paper were studied in detail from the points of view of swellability, shrinkage, reusability, and stability against acidic, alkaline, and oxidative reagents.
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The Personal Alert Safety System (PASS) is an alarm signal device carried by firefighters to help rescuers locate and extricate downed firefighters. A fire creates temperature gradients and inhomogeneous time-varying temperature, density, and flow fields that modify the acoustic properties of a room. To understand the effect of the fire on an alarm signal, experimental measurements of head-related transfer functions (HRTF) in a room with fire are presented in time and frequency domains. The results show that low-frequency (<1000 Hz) modes in the HRTF increase in frequency and higher-frequency modal structure weakens and becomes unstable in time. In the time domain, the time difference of arrival between the ears changes and becomes unstable over time. Both of these effects could impact alarm signal detection and localization. The receive level of narrowband tones is presented that shows that the fire makes the receive level of a source vary by > 10 dB. All of these effects could impact the detection and localization of the PASS alarm and have life safety consequences.
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Localización de Sonidos , Acústica , CefalometríaRESUMEN
The quality of atmospheric air of Burgas city, Bulgaria was analyzed in relation to PAHs in two particulate matter fractions - 2.5 µm and 10 µm. It was found that PAHs registered in PM10 represent entirely the ones registered in PM2.5 - an indication that the particulate PAHs in ambient air of Burgas for the sampling period are associated with the fine PM fraction. The PAH compounds with highest concentrations are mainly associated with coal combustion, diesel and gasoline vehicle and biomass burning, which is further confirmed by the calculated diagnostic ratios. The combustion-derived PAHs represent on average 86.6 ± 2.8% of total PAHs concentration. The linear regression analysis showed strong and statistically meaningful correlations between PM fractions and PAHs indicating the influence of similar local events and emission sources of pollution. PM2.5 or PM10 relationships with PAHs were significant but lower correlation coefficients were observed for low-molecular weight (LMW) PAHs in comparison to middle-molecular weight (MMW) and higher-molecular weight (HMW) PAHs, due to their lower presence in particulates and higher partition in gaseous atmospheric phase. Further significant correlations were found with wind speed, solar radiation and atmospheric pressure as well as NO2 and O3 ambient concentration. The calculated excess cancer risks are twice as much as acceptable limit.
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Contaminantes Atmosféricos , Contaminación del Aire , Contaminantes Ambientales , Hidrocarburos Policíclicos Aromáticos , Contaminantes Atmosféricos/análisis , Contaminación del Aire/análisis , Bulgaria , China , Carbón Mineral/análisis , Monitoreo del Ambiente , Contaminantes Ambientales/análisis , Material Particulado/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Estaciones del AñoRESUMEN
The human epidermal growth factor receptor 2 (HER-2) protein is a member of the epidermal growth factor receptor (EGFR or ErbB) family and is a transmembrane tyrosine kinase receptor. HER-2 is highly regulated in ovarian, lung, gastric, oral, and breast cancers. The low specificity, complexity, expensiveness and the lack of sensitivity are essential restrictions in traditional diagnosis methods such as FISH, immunohistochemistry and PCR and these disadvantages led to the need for more studies on alternative methods. Biosensor technology has greatly affected the quality of human life owing to its features including, sensitivity, specificity, and rapid diagnosis and monitoring of different patient diseases. In this review article, we examine various biosensors, considering that they have been categorized based on the transducers used including piezoelectric biosensors, optical sensors such as fluorescence and surface plasmon resonance, and electrochemical types for the diagnosis of HER-2 and the effectiveness of some drugs against that. Attention to developing some types of biosensor devices such as colorimetric biosensors for HER-2 detection can be an important point in future studies.
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Técnicas Biosensibles , Neoplasias , Biomarcadores de Tumor , Técnicas Biosensibles/métodos , Técnicas Electroquímicas/métodos , Humanos , Neoplasias/diagnóstico , Receptor ErbB-2/genéticaRESUMEN
Employing phase-change materials (PCM) is considered a very efficient and cost-effective option for addressing the mismatch between the energy supply and the demand. The high storage density, little temperature degradation, and ease of material processing register the PCM as a key candidate for the thermal energy storage system. However, the sluggish response rates during their melting and solidification processes limit their applications and consequently require the inclusion of heat transfer enhancers. This research aims to investigate the potential enhancement of circular fins on intensifying the PCM thermal response in a vertical triple-tube casing. Fin arrays of non-uniform dimensions and distinct distribution patterns were designed and investigated to determine the impact of modifying the fin geometric characteristics and distribution patterns in various spatial zones of the heat exchanger. Parametric analysis on the various fin structures under consideration was carried out to determine the most optimal fin structure from the perspective of the transient melting evolution and heat storage rates while maintaining the same design limitations of fin material and volume usage. The results revealed that changing the fin dimensions with the heat-flow direction results in a faster charging rate, a higher storage rate, and a more uniform temperature distribution when compared to a uniform fin size. The time required to fully charge the storage system (fully melting of the PCM) was found to be reduced by up to 10.4%, and the heat storage rate can be improved by up to 9.3% compared to the reference case of uniform fin sizes within the same fin volume limitations.
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Herein, two distinct nanocomposites of CaTiO3 micro-cubes and polygonal SrFe12O19, both decorated with NiO nanoparticles, were successfully synthesized using hydrothermal method. The physico-chemical features of as-prepared samples were evaluated via XRD, FTIR, UV-vis, BET, XPS, FESEM and EDS analysis. Microwave attenuation features of as-prepared single layer absorbers were determined by VNA analysis in 2-18 GHz. Simulation confirmation was checked by preparing a bi-layer samples and evaluating it using VNA analysis after finding the appropriate thickness of each layer. The reflection loss from each single layer samples containing 20 wt% of each CaTiO3/NiO and SrFe12O19/NiO nanocomposites were -16 dB and -35 dB at 6.3 GHz with 2.5 mm matching thickness respectively. However, the RL was -34 dB at 10 GHz frequency with 2 mm thickness in a bilayer absorber with SrFe12O19/NiO nanocomposite layer put as absorbing layer with 1 mm thickness and CaTiO3/NiO positioned as matching layer with 1 mm thickness. Furthermore, at the X-band frequency, approximately entire band absorption is obtained. The findings demonstrate that adjusting the order and thickness of the layers in a bilayer absorber may readily improve microwave absorption performance. By comparing the results of simulation with real prepared bilayer absorbers, we found that with a 2 mm overall thickness, the bi-layer absorbers display accurate RL values, but not the matching frequency monitored in the simulation process. In reality, this discrepancy was unavoidable.