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Over the past two decades, there has been extensive research into surveillance methods for the post-endovascular repair of abdominal aortic aneurysms, highlighting the importance of these technologies in supplementing or even replacing conventional image-screening modalities. This review aims to provide an overview of the current status of alternative surveillance solutions for endovascular aneurysm repair, while also identifying potential aneurysm features that could be used to develop novel monitoring technologies. It offers a comprehensive review of these recent clinical advances, comparing new and standard clinical practices. After introducing the clinical understanding of abdominal aortic aneurysms and exploring current treatment procedures, the paper discusses the current surveillance methods for endovascular repair, contrasting them with recent pressure-sensing technologies. The literature on three commercial pressure-sensing devices for post-endovascular repair surveillance is analyzed. Various pre-clinical and clinical studies assessing the safety and efficacy of these devices are reviewed, providing a comparative summary of their outcomes. The review of the results from pre-clinical and clinical studies suggests a consistent trend of decreased blood pressure in the excluded aneurysm sac post-repair. However, despite successful pressure readings from the aneurysm sac, no strong link has been established to translate these measurements into the presence or absence of endoleaks. Furthermore, the results do not allow for a conclusive determination of ongoing aneurysm sac growth. Consequently, a strong clinical need persists for monitoring endoleaks and aneurysm growth following endovascular repair.
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Aneurisma de la Aorta Abdominal , Procedimientos Endovasculares , Aneurisma de la Aorta Abdominal/cirugía , Humanos , Procedimientos Endovasculares/métodos , Procedimientos Endovasculares/instrumentación , Monitoreo Fisiológico/métodos , Monitoreo Fisiológico/instrumentación , Presión Sanguínea/fisiología , Presión , Prótesis e Implantes , Reparación Endovascular de AneurismasRESUMEN
Abdominal aortic aneurysm (AAA) is a dilation of the aorta artery larger than its normal diameter (>3 cm). Endovascular aneurysm repair (EVAR) is a minimally invasive treatment option that involves the placement of a graft in the aneurysmal portion of the aorta artery. This treatment requires multiple follow-ups with medical imaging, which is expensive, time-consuming, and resource-demanding for healthcare systems. An alternative solution is the use of wireless implantable sensors (WIMSs) to monitor the growth of the aneurysm. A WIMS capable of monitoring aneurysm size longitudinally could serve as an alternative monitoring approach for post-EVAR patients. This study has developed and characterised a three-coil inductive read-out system to detect variations in the resonance frequency of the novel Z-shaped WIMS implanted within the AAA sac. Specifically, the spacing between the transmitter and the repeater inductors was optimised to maximise the detection of the sensor by the transmitter inductor. Moreover, an experimental evaluation was also performed for different orientations of the transmitter coil with reference to the WIMS. Finally, the FDA-approved material nitinol was used to develop the WIMS, the transmitter, and repeater inductors as a proof of concept for further studies. The findings of the characterisation from the air medium suggest that the read-out system can detect the WIMS up to 5 cm, regardless of the orientation of the Z-shape WIMS, with the detection range increasing as the orientation approaches 0°. This study provides sufficient evidence that the proposed WIMS and the read-out system can be used for AAA expansion over time.
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Aneurisma de la Aorta Abdominal , Tecnología Inalámbrica , Aneurisma de la Aorta Abdominal/cirugía , Aneurisma de la Aorta Abdominal/diagnóstico , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Tecnología Inalámbrica/instrumentación , Humanos , Monitoreo Fisiológico/métodos , Monitoreo Fisiológico/instrumentación , Prótesis e Implantes , Diseño de EquipoRESUMEN
Birth asphyxia is a potential cause of death that is also associated with acute and chronic morbidities. The traditional and immediate approach for monitoring birth asphyxia (i.e., arterial blood gas analysis) is highly invasive and intermittent. Additionally, alternative noninvasive approaches such as pulse oximeters can be problematic, due to the possibility of false and erroneous measurements. Therefore, further research is needed to explore alternative noninvasive and accurate monitoring methods for asphyxiated neonates. This study aims to investigate the prominent ECG features based on pH estimation that could potentially be used to explore the noninvasive, accurate, and continuous monitoring of asphyxiated neonates. The dataset used contained 274 segments of ECG and pH values recorded simultaneously. After preprocessing the data, principal component analysis and the Pan-Tompkins algorithm were used for each segment to determine the most significant ECG cycle and to compute the ECG features. Descriptive statistics were performed to describe the main properties of the processed dataset. A Kruskal-Wallis nonparametric test was then used to analyze differences between the asphyxiated and non-asphyxiated groups. Finally, a Dunn-Sidák post hoc test was used for individual comparison among the mean ranks of all groups. The findings of this study showed that ECG features (T/QRS, T Amplitude, Tslope, Tslope/T, Tslope/|T|, HR, QT, and QTc) based on pH estimation differed significantly (p < 0.05) in asphyxiated neonates. All these key ECG features were also found to be significantly different between the two groups.
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Asfixia Neonatal , Electrocardiografía , Humanos , Electrocardiografía/métodos , Recién Nacido , Concentración de Iones de Hidrógeno , Asfixia Neonatal/diagnóstico , Asfixia Neonatal/fisiopatología , Algoritmos , Estudios de Factibilidad , Análisis de los Gases de la Sangre/métodos , Análisis de Componente Principal , Femenino , MasculinoRESUMEN
Cardiac wireless implantable medical devices (CWIMD) have brought a paradigm shift in monitoring and treating various cardiac conditions, including heart failure, arrhythmias, and hypertension. One of the key elements in CWIMD is the implant antenna which uses radio frequency (RF) technology to wirelessly communicate and transmit data to external devices. However, wireless communication with a deeply implanted antenna using RF can be challenging due to the significant loss of electromagnetic (EM) signal at the air-skin interface, and second, due to the propagation and reflection of EM waves from different tissue boundaries. The air-skin interface loss of the EM wave is pronounced due to the absence of a matching medium. This paper investigates the EM propagation losses in the human body and presents a choice of optimal frequency for the design of the cardiac implant antenna and the dielectric properties of the matching medium. First, the dielectric properties of all tissues present in the human thorax including skin, fat, muscle, cartilage, and heart are analyzed as a function of frequency to study the EM wave absorption at different frequencies. Second, the penetration of EM waves inside the biological tissues is analyzed as a function of frequency. Third, a transmission line (TL) formalism approach is adopted to examine the optimal frequency band for designing a cardiac implant antenna and the matching medium for the air-skin interface. Finally, experimental validation is performed at two ISM frequencies, 433 MHz and 915 MHz, selected from the optimal frequency band (0.4-1.5 GHz) suggested by our analytical investigation. For experimental validation, two off-the-shelf flexible dipole antennas operating at selected ISM frequencies were used. The numerical and experimental findings suggested that for the specific application of a cardiac implant with a penetration depth of 7-17 cm, the most effective frequency range for operation is within 0.4-1.5 GHz. The findings based on the dielectric properties of thorax tissues, the penetration depth of EM waves, and the optimal frequency band have provided valuable information on developing and optimizing CWIMDs for cardiac care applications.
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Corazón , Prótesis e Implantes , Humanos , Estudios de Factibilidad , Arritmias Cardíacas , Ondas de Radio , Tecnología InalámbricaRESUMEN
The wireless monitoring of key physiological parameters such as heart rate, respiratory rate, temperature, and pressure can aid in preventive healthcare, early diagnosis, and patient-tailored treatment. In wireless implantable sensors, the distance between the sensor and the reader device is prone to be influenced by the operating frequency, as well as by the medium between the sensor and the reader. This manuscript presents an ex vivo investigation of the wireless linkage between an implantable sensor and an external reader for medical applications. The sensor was designed and fabricated using a cost-effective and accessible fabrication process. The sensor is composed of a circular planar inductor (L) and a circular planar capacitor (C) to form an inductor-capacitor (LC) resonance tank circuit. The reader system comprises a readout coil and data acquisition instrumentation. To investigate the effect of biological medium on wireless linkage, the readout distance between the sensor and the readout coil was examined independently for porcine and ovine tissues. In the bench model, to mimic the bio-environment for the investigation, skin, muscle, and fat tissues were used. The relative magnitude of the reflection coefficient (S11) at the readout coil was used as a metric to benchmark wireless linkage. A readable linkage signal was observed on the readout coil when the sensor was held up to 2.5 cm under layers of skin, muscle, and fat tissue. To increase the remote readout distance of the LC sensor, the effect of the repeater coil was also investigated. The experimental results showed that the magnitude of the reflection coefficient signal was increased 3-3.5 times in the presence of the repeater coil, thereby increasing the signal-to-noise ratio of the detected signal. Therefore, the repeater coil between the sensor and the readout coil allows a larger sensing range for a variety of applications in implanted or sealed fields.
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Prótesis e Implantes , Tecnología Inalámbrica , Animales , Ovinos , Porcinos , VibraciónRESUMEN
An alternative method of electrochemical oxidation was employed to degrade persistent compounds in the form of antibiotics using strong oxidizing agents such as hydroxyl ions. A 24 factorial design was employed to check the effect of four factors namely pH, current density, electrolysis time and electrolyte concentration set at their high (+) and low (-) levels on the antibiotics (amoxicillin, ciprofloxacin and erythromycin) degradation in water. The response was obtained in the form of COD (chemical oxygen demand) removal. A prediction model was developed to predict the values of COD removal. Later the main effect, contribution and interactions were studied with Design Expert Software 7.0. About 89.5% COD removal was obtained when pH and time were set at their high level and the other two factors at their low level. It was determined that the pH when set at high level (pH 9) had the most effect (24.68) and contribution (43.6) in the degradation process and hence the removal of COD. This technology of electrochemical oxidation can be employed in industries to efficiently remove pharmaceuticals, paints, dyes and other organic compounds.
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Amoxicilina/análisis , Análisis de la Demanda Biológica de Oxígeno/métodos , Ciprofloxacina/análisis , Técnicas Electroquímicas/métodos , Eritromicina/análisis , Agua/análisis , Amoxicilina/metabolismo , Antibacterianos/análisis , Antibacterianos/metabolismo , Ciprofloxacina/metabolismo , Eritromicina/metabolismo , Agua/metabolismo , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/metabolismo , Purificación del Agua/métodosRESUMEN
Microwave tomography (MWT) can be used as an alternative modality for monitoring human bone health. Studies have found a significant dielectric contrast between healthy and diseased human trabecular bones. A set of diverse bone phantoms were developed based on single-pole Debye parameters of osteoporotic and osteoarthritis human trabecular bones. The bone phantoms were designed as a two-layered circular structure, where the outer layer mimics the dielectric properties of the cortical bone and the inner layer mimics the dielectric properties of the trabecular bone. The electromagnetic (EM) inverse scattering problem was solved using a distorted Born iterative method (DBIM). A compressed sensing-based linear inversion approach referred to as iterative method with adaptive thresholding for compressed sensing (IMATCS) has been employed for solving the underdetermined set of linear equations at each DBIM iteration. To overcome the challenges posed by the ill-posedness of the EM inverse scattering problem, the L2-based regularization approach was adopted in the amalgamation of the IMATCS approach. The simulation results showed that osteoporotic and osteoarthritis bones can be differentiated based on the reconstructed dielectric properties even for low values of the signal-to-noise ratio. These results show that the adopted approach can be used to monitor bone health based on the reconstructed dielectric properties.
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Densidad Ósea , Huesos/diagnóstico por imagen , Imágenes de Microonda , Fantasmas de Imagen , Algoritmos , HumanosRESUMEN
Adrenal gland-induced hypertension results from underlying adrenal gland disorders including Conn's syndrome, Cushing's syndrome, and Pheochromocytoma. These adrenal disorders are a risk for cardiovascular and renal morbidity and mortality. Clinically, treatment for adrenal gland-induced hypertension involves a pharmaceutical or surgical approach. The former presents very significant side effects whereas the latter can be ineffective in cases where the adrenal disorder reoccurs in the remaining contralateral adrenal gland. Due to the limitations of existing treatment methods, minimally invasive treatment options like microwave ablation (MWA) have received significant attention for treating adrenal gland disorders. A precise comprehension of the dielectric properties of human adrenal glands will help to tailor energy delivery for MWA therapy, thus offering the potential to optimise treatments and minimise damage to surrounding tissues. This study reports the ex vivo dielectric properties of human adrenal glands, including the cortex, medulla, capsule, and tumours, based on the data obtained from four patients (diagnosed with Conn's syndrome, Cushing's syndrome, and Pheochromocytoma) who underwent unilateral adrenalectomy at the University Hospital Galway, Ireland. An open-ended coaxial probe measurement technique was used to measure the dielectric properties for a frequency range of 0.5-8.5 GHz. The dielectric properties were fitted using a two-pole Debye model, and a weighted least squares method was employed to optimise the model parameters. Moreover, the dielectric properties of adrenal tissues and tumours were compared across frequencies commonly used in MWA, including 915 MHz, 2.45 GHz, and 5.8 GHz. The study found that the dielectric properties of adrenal tumours were influenced by the presence of lipid-rich adenomas, and the dielectric properties of Cushing's syndrome tumour were lowest in comparison to the tumours in patients diagnosed with Conn's syndrome and Pheochromocytoma. Furthermore, a notable difference was observed in the dielectric properties of the medulla and cortex among patients diagnosed with Conn's syndrome, Cushing's syndrome, and Pheochromocytoma. These findings have significant implications for the diagnosis and treatment of adrenal tumours, including the optimisation of MWA therapy for precise ablation of adrenal masses.
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Neoplasias de las Glándulas Suprarrenales , Glándulas Suprarrenales , Síndrome de Cushing , Hipertensión , Microondas , Feocromocitoma , Humanos , Neoplasias de las Glándulas Suprarrenales/cirugía , Microondas/uso terapéutico , Glándulas Suprarrenales/cirugía , Glándulas Suprarrenales/patología , Hipertensión/terapia , Feocromocitoma/cirugía , Síndrome de Cushing/cirugía , Técnicas de Ablación/métodos , Femenino , Masculino , Hiperaldosteronismo/cirugía , Hiperaldosteronismo/terapia , Adrenalectomía , Persona de Mediana EdadRESUMEN
Wireless implantable medical devices (WIMDs) have seen unprecedented progress in the past three decades. WIMDs help clinicians in better-understanding diseases and enhance medical treatment by allowing for remote data collection and delivering tailored patient care. The wireless connectivity range between the external reader and the implanted device is considered one of the key design parameters in WIMD technology. One of the common modes of communication in battery-free WIMDs is inductive coupling, where the power and data between the reader and the implanted device are transmitted via magnetically coupled inductors. The design and shape of these inductors depend on the requirements of the application. Several studies have reported models of standard planar inductors such as circular, square, hexagonal, and octagonal in medical applications. However, for applications, constrained by narrow implantable locations, elliptical planar inductors may perform better than standard-shaped planar inductors. The aim of this study is to develop a numerical model for elliptical inductors. This model allows for the calculation of the inductance of the elliptical planar inductor and its parasitic components, which are key design parameters for the development of WIMDs powered by inductive coupling. An area transformation technique is used to transform and derive elliptical inductor formulas from standard circular inductor formulas. The proposed model is validated for various combinations of the number of turns, trace width, trace separation, and different inner and outer diameters of the elliptical planar inductor. For a thorough experimental validation of the proposed numerical model, more than 75 elliptical planar inductors were fabricated, measured, and compared with the numerical output of the proposed model. The mean error between the measured inductor parameters and numerical estimates using the proposed model is <5%, with a standard deviation of <3.18%. The proposed model provides an accurate analytical method for estimating and optimizing elliptical planar inductor parameters using a combination of current sheet expression and area transformation techniques. An elliptical planar inductor integrated with a sensing element can be used as a wireless implant to monitor the physiological signal from narrow implantation sites.
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Asphyxia, a leading cause of illness and death in newborns, can be improved by early detection and management. Arterial blood gas (ABG) analysis is commonly used to diagnose and manage asphyxia, but it is invasive and carries risks. Dermal interstitial fluid (ISF) is an alternative physiological fluid that can provide valuable information about a person's health. ISF is more sensitive to severe hypoxia and metabolic disorders compared to blood, making it an attractive option for minimally invasive asphyxia detection using biosensors. However, obtaining ISF samples from humans is challenging due to ethical concerns and sampling difficulties. To address this, researchers are developing ISF-mimicking solutions as substitutes for early testing and evaluation of biosensors. This paper focuses on the development of these solutions for bench-based testing and validation of continuous asphyxia-monitoring biosensors. With an understanding of the factors influencing system quality and performance, these solutions can aid in the design of biosensors for in vivo monitoring of dermal ISF. Monitoring interstitial fluid pH levels can provide valuable insights into the severity and progression of asphyxia, aiding in accurate diagnosis and informed treatment decisions. In this study, buffer solutions were prepared to mimic the pH of ISF, and their electrical properties were analyzed. The results suggest that certain buffers can effectively mimic metabolic acidosis associated with asphyxia (pH < 7.30), while others can mimic metabolic alkalosis (pH > 7.45). Overall, this research contributes to the development of ISF-mimicking solutions and lays the groundwork for biosensor systems that monitor dermal ISF in real time.
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Cardiac catheter ablation (CCA) is a common method used to correct cardiac arrhythmia. Pulsed Field Ablation (PFA) is a recently-adapted CCA technology whose ablation is dependent on electrode and waveform parameters (factors). In this work, the use of the Design of Experiments (DoE) methodology is investigated for the design and optimization of a PFA device. The effects of the four factors (input voltage, electrode spacing, electrode width, and on-time) and their interactions are analyzed. An empirical model is formed to predict and optimize the ablation size responses. Based on the ranges tested, the significant factors were the input voltage, the electrode spacing, and the on time, which is in line with the literature. Two-factor interactions were found to be significant and need to be considered in the model. The resulting empirical model was found to predict ablation sizes with less than 2.1% error in the measured area and was used for optimization. The findings and the strong predictive model developed highlight that the DoE approach can be used to help determine PFA device design, to optimize for certain ablation zone sizes, and to help inform device design to tackle specific cardiac arrhythmias.
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Self-assembled polymer vesicles have emerged as exciting and promising materials for their potential application in drug delivery, but the dynamics of stimuli-responsive polymers in these areas with pendant functionality in order to understand the structure-property relationship under different physicochemical conditions is still open to discussion. In this work, nitroxide radical-containing copolymers were synthesized and utilized to investigate local dynamics in their vesicular assemblies. Herein, electron paramagnetic resonance (EPR) spectroscopy was applied to reveal the smart supramolecular vesicular structure and polymer chain dynamics in stimuli-responsive controlled assemblies by considering molecular-level interactions. These interactions and dynamics were dependent on the microenvironment of the assemblies, which might be affected by physicochemical parameters such as radical concentration, pH, redox agent, polarity, and viscosity. These observations help to accomplish quantitative insights into the stimuli-responsive colloidal vesicular assemblies. The vesicles were used as an anticancer drug carrier, which showed high drug loading efficiency (63.65%). The reduction-responsive prompt disassembly accelerated the release. Furthermore, the biocompatibility and anticancer activity were examined by cellular experiments against normal fibroblasts (L929) and human cervical cancer (HeLa) cell lines, respectively. The results demonstrate that this effort provides an easy strategy for designing controllable stimuli-responsive polymer nanosystems which promotes their promising application in cancer treatment.
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The dielectric properties of bones are found to be influenced by the demineralisation of bones. Therefore, microwave imaging (MWI) can be used to monitor in vivo dielectric properties of human bones and hence aid in the monitoring of osteoporosis. This paper presents the feasibility analysis of the MWI device for monitoring osteoporosis. Firstly, the dielectric properties of tissues present in the human heel are analysed. Secondly, a transmission line (TL) formalism approach is adopted to examine the feasible frequency band and the matching medium for MWI of trabecular bone. Finally, simplified numerical modelling of the human heel was set to monitor the penetration of E-field, the received signal strength, and the power loss in a numerical model of the human heel. Based on the TL formalism approach, 0.6-1.9-GHz frequency band is found to feasible for bone imaging purpose. The relative permittivity of the matching medium can be chosen between 15 and 40. The average percentage difference between the received signal for feasible and inconvenient frequency band was found to be 82%. The findings based on the dielectric contrast of tissues in the heel, the feasible frequency band, and the finite difference time domain simulations support the development of an MWI prototype for monitoring osteoporosis.
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Imágenes de Microonda , Osteoporosis , Huesos/diagnóstico por imagen , Estudios de Factibilidad , Humanos , Microondas , Osteoporosis/diagnóstico por imagenRESUMEN
HYPOTHESIS: Organic radical polymers with tailored pendant functionalities have emerged as exciting and promising materials for their application versatility. Moreover, eco-friendly polymer-based organic nanomaterials with redox-active pendant side groups can replace the harmful heavy metal-based inorganic materials. On the other hand, self-assembled nanomaterials are of great interest and attracted more attention recently for their promising application in different advanced fields, but it is yet challenging to predict suitable hydrophilic-lipophilic balance (HLB) for stimuli-responsive random copolymers assembly due to structural irregularity. Among several experimental techniques, electron paramagnetic resonance (EPR) spectroscopy plays a unique and promising role in revealing structural and dynamic information of nanostructured radical containing materials. EXPERIMENTS: In this study, a series of spin labeled amphiphilic random copolymers poly(methyl methacrylate-co-acrylic acid) have been synthesized and characterized by FT-IR, UV-Vis spectroscopies, TGA, DSC and water contact angle (CA) techniques. Their electrochemical properties have been determined by cyclic voltammetry (CV) in different organic solvents. EPR spectroscopy has been applied with other analytical techniques to elucidate the smart supramolecular nanoparticles (SNPs) formation, stimuli-responsiveness and structural changes through the dynamics of different molecular interactions. FINDINGS: The structural and dynamic information of self-assembled nanoparticles have been observed to be dependent on multiple-stimuli-responsiveness in different microenvironments by applying physiological and chemical parameters such as the different concentration of radicals, pH, temperature, nature of the solvent and reducing agent. The obtained results reveal the knowledge to understand insight into the mechanism for the formation of stimuli-responsive colloidal nanoparticles assembled from amphiphilic random copolymers with apt HLB value. The CV results reveal that the charge transfer process of the nanoparticles in solution was diffusion regulated and depended on the accessibility of radicals. The radical (spin labeled) polymers offer a broad way to develop stimuli-responsive materials in various colloidal nanostructures by changing the microenvironment, appreciating their potential advanced applications in electronic devices, catalysis, stimuli-triggered drug/gene delivery and reactive oxygen species (ROS) scavenger.
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Different hydrogels of poly(acrylamide-co-3-acrylamido phenylboronic acid-co-chitosan grafted maleic acid) (P(AM-co-AAPBA-co-CSMA)s) were synthesized using poly(ethylene glycol) diacrylate (PEGDA) as a crosslinker to serve for glucose sensing and insulin delivery. The structure and morphology of the hydrogels, named as CSPBA were studied by FTIR and SEM, while the mechanical properties were tested using dynamic mechanical analysis (DMA) and universal testing machine. The prepared hydrogels shrinked at low glucose concentration due to the 2:1 boronate-glucose binding, and swelled at high glucose concentration because of 1:1 boronate-glucose complexation. Both binding mechanisms are useful for glucose sensing and insulin delivery. The integration of CSMA into hydrogels network not only enhanced the response to glucose at physiological pH, but also improved the mechanical properties and increased the encapsulation efficiency of the prepared hydrogels. These CSPBA may find potential as implantable hydrogels in applications were continuous glucose monitoring and controlled release is beneficial.
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Quitosano/química , Glucosa/química , Hidrogeles/química , Técnicas Biosensibles , Fenómenos Químicos , Técnicas de Química Sintética , Portadores de Fármacos , Liberación de Fármacos , Insulina/administración & dosificación , Espectroscopía de Resonancia Magnética , Maleatos , Polietilenglicoles , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
Antibiotics discovery was a significant breakthrough in the field of therapeutic medicines, but the over (mis)use of such antibiotics (in parallel) caused the increasing number of resistant bacterial species at an ever-higher rate. This study was thus devised to assess the multi-drug resistant bacteria present in sanitation-related facilities in human workplaces. In this regard, samples were collected from different gender, location, and source-based facilities, and subsequent antibiotic sensitivity testing was performed on isolated bacterial strains. Four classes of the most commonly used antibiotics i.e., ß-lactam, Aminoglycosides, Macrolides, and Sulphonamides, were evaluated against the isolated bacteria. The antibiotic resistance profile of different (70) bacterial strains showed that the antibiotic resistance-based clusters also followed the grouping based on their isolation sources, mainly the gender. Twenty-three bacterial strains were further selected for their 16s rRNA gene based molecular identification and for phylogenetic analysis to evaluate the taxonomic evolution of antibiotic resistant bacteria (ARB). Moreover, the bacterial resistance to Sulphonamides and beta lactam was observed to be the most and to Aminoglycosides and macrolides as the least. Plasmid curing was also performed for multidrug resistant (MDR) bacterial strains, which significantly abolished the resistance potential of bacterial strains for different antibiotics. These curing results suggested that the antibiotic resistance determinants in these purified bacterial strains are present on respective plasmids. Altogether, the data suggested that the human workplaces are the hotspot for the prevalence of MDR bacteria and thus may serve as the source of horizontal gene transfer and further transmission to other environments.
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Bacterias/efectos de los fármacos , Bacterias/aislamiento & purificación , Farmacorresistencia Bacteriana Múltiple , Cuartos de Baño , Lugar de Trabajo , Bacterias/genética , Farmacorresistencia Bacteriana Múltiple/genética , Microbiología Ambiental , Femenino , Humanos , Higiene , Masculino , Exposición Profesional , Pakistán , Filogenia , Plásmidos , Prevalencia , Factores R , ARN Ribosómico 16S/genética , SaneamientoRESUMEN
The objective of this study is to determine whether in vitro dielectric properties of human trabecular bones, can distinguish between osteoporotic and osteoarthritis patients' bone samples. Specifically this study enlightens intra-patient variation of trabecular bone microarchitecture and dielectric properties, inter-disease comparison of bone dielectric properties, and finally establishes the correlation to traditional bone histomorphometry parameter (bone volume fraction) for diseased bone tissue. Bone cores were obtained from osteoporotic and osteoarthritis patients (n = 12). These were scanned using microCT to examine bone volume fraction. An open-ended coaxial probe measurement technique was employed to measure dielectric properties over the 0.5 - 8.5 GHz frequency range. The dielectric properties of osteoarthritis patients are significantly higher than osteoporotic patients; with an increase of 41% and 45% for relative permittivity and conductivity respectively. The dielectric properties within each patient vary significantly, variation in relative permittivity and conductivity was found to be greater than 25% and 1.4% respectively. A weak correlation (râ = â 0.5) is observed between relative permittivity and bone volume fraction. Osteoporotic and osteoarthritis bones can be differentiated based on difference of dielectric properties. Although these do not correlate strongly to bone volume fraction, it should be noted that bone volume fraction is a poor predictor of fracture risk. The dielectric properties of bones are found to be influenced by mineralization levels of bones. Therefore, dielectric properties of bones may have potential as a diagnostic measure of osteoporosis.
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Hueso Esponjoso , Microondas , Hueso Esponjoso/diagnóstico por imagen , Impedancia Eléctrica , Humanos , Osteoartritis/diagnóstico por imagen , Osteoporosis/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
Osteoporosis is one of the most common diseases that leads to bone fractures. Dual-energy X-ray absorptiometry is currently employed to measure the bone mineral density and to diagnose osteoporosis. Alternatively, the dielectric properties of bones are found to be influenced by bone mineral density; hence, dielectric properties of bones may potentially be used to diagnose osteoporosis. Microwave tomographic imaging is currently in development to potentially measure in vivo dielectric properties of bone. Therefore, the foci of this work are to summarize all available dielectric data of bone in the microwave frequency range and to analyze the confounders that may have resulted in variations in reported data. This study also compares the relationship between the dielectric properties and bone quality reported across different studies. The review suggests that variations exist in the dielectric properties of bone and the relationship between bone volume fraction and dielectric properties is in agreement across all studies. Conversely, the evidence of a relationship between bone mineral density and dielectric properties is inconsistent across the studies. This summary of dielectric data of bone along with a comparison of the relationship between the dielectric properties and bone quality will accelerate the development of microwave tomographic imaging devices for the monitoring of osteoporosis. Graphical abstract á .
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Huesos/fisiopatología , Electricidad , Osteoporosis/diagnóstico , Osteoporosis/fisiopatología , Animales , Densidad Ósea , Huesos/patología , Conductividad Eléctrica , HumanosRESUMEN
The dielectric properties are key parameters that quantify the interaction between electromagnetic waves and human biological tissues. In particular, the development of electromagnetic-based medical technologies rely on knowledge of the dielectric properties of bone, specifically for applications such as electrical stimulation and bone health monitoring. Electrical stimulation is used in clinics to promote the healing of bone fractures, treating non-unions, congenital pseudarthrosis, bone regeneration and during bone implant procedures. The response of the bone to any external electrical stimulation is governed by the dielectric properties of the bone, which vary with the applied frequency of the stimuli. Bone mineral density is considered a key indicator of osteoporosis diagnosis, and is assumed to be related to the dielectric properties of the bone. Therefore, dielectric properties of bones may potentially be used to diagnose osteoporosis. The bone dielectric properties can be assessed non-invasively for bone health monitoring. Several research studies have reported dielectric properties of cortical and trabecular bones in recent literature. Since dielectric properties of bone determine the response of the tissue to therapies, it is important to compile and analyze the reported dielectric data in order to have a thorough understanding of these properties. It is established from the literature that the low frequency (10 Hz-1 GHz) dielectric properties of bone are particularly important in diagnostic applications, as the correlation between the dielectric properties and bone mineral density is more significant than at higher frequencies. In this paper, the low frequency dielectric properties of the bone reported in the literature are compiled and quantitatively analysed. The results suggest that there is a significant inter- and intra-species variation in the reported dielectric data from human, bovine, porcine, and rat bone tissues. Moreover, the relationship between the dielectric properties and bone mineral density is inconsistent across the various studies, indicating that further research in this area is needed.
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Microbially enhanced availability and phytoextraction is a promising technique for phytoremediation of lead (Pb). In this study, Pb resistant strains were isolated and investigated for potential effects on plant growth and Pb phytoextraction. Incubation experiments were carried for inoculated and un-inoculated soil containing different levels of Pb. Results revealed that 20% of the isolated bacteria could tolerate Pb up to 800â¯mgâ¯L-1. Five Pb resistant strains with plant growth promoting (PGP) abilities were evaluated for possible influence on water soluble Pb through soil incubation experiments and significant increase i.e. 1.85- and 1.49-folds in water soluble Pb was observed for NCCP-1848 and NCCP-1862 strains, respectively. Pot experiments indicated significantly higher uptake by Pelargonium hortorum than that by Mesembryanthemum criniflorrum at all levels of soil Pb concentrations with the highest increase (1.9-folds) in plants inoculated with NCCP-1848 followed by NCCP-1862 (1.8-folds increase) compared to the control (Pb and without bacterial strain). The strains NCCP-1848 and NCCP-1862 were identified by 16S rRNA gene sequencing as Microbacterium sp. and Klebsiella sp. The results of present study suggest that Pb resistant plant growth promoting bacteria can serve as an effective bio-inoculant through wide action spectrum for maximizing efficiency of phytoremediation system.