Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 37
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Rep ; 14(1): 9839, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38684724

RESUMO

This study explores the dynamical rotary motion of a charged axisymmetric spinning rigid body (RB) under the effect of a gyrostatic moment (GM). The influence of transverse and invariable body fixed torques (IBFTs), and an electromagnetic force field, is also considered. Euler's equations of motion (EOM) are utilized to derive the regulating system of motion for the problem in a suitable formulation. Due to the lack of torque exerted along the spin axis and the nearly symmetrical nature of the RB, the spin rate is nearly unchanged. Assuming slight angular deviations of the spin axis relative to a fixed direction in space, it is possible to derive approximate analytical solutions (AS) in closed form for the attitude, translational, and rotational movements. These concise solutions that are expressed in complex form are highly effective in analyzing the maneuvers performed by spinning RBs. The study focuses on deriving the AS for various variables including angular velocities, Euler's angles, angular momentum, transverse displacements, transverse velocities, axial displacement, and axial velocity. The graphical simulation of the subsequently obtained solutions is presented to show their precision. Furthermore, the positive impacts that alterations in the body's parameters have on the motion's behavior are presented graphically. The corresponding phase plane curves, highlighting the influence of different values in relation to the electromagnetic force field, the GM, and the IBFTs are drawn to analyze the stability of the body's motion. This study has a significant role in various scientific and engineering disciplines. Its importance lies in its ability to optimize mechanical systems, explain celestial motion, and enhance spacecraft performance.

2.
Sci Rep ; 14(1): 5390, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38443505

RESUMO

This paper aims to explore the rotatory spatial motion of an asymmetric rigid body (RB) under constant body-fixed torques and a nonzero first component gyrostatic moment vector (GM). Euler's equations of motion are used to derive a set of dimensionless equations of motion, which are then proposed for the stability analysis of equilibrium points. Specifically, this study develops 3D phase space trajectories for three distinct scenarios; two of them are applied constant torques that are directed on the minor and major axes, while the third one is the action of applied constant torque on the body's middle axis. Novel analytical and simulation results for both scenarios of constant torque applied along the minor and middle axes are provided in the context of separatrix surfaces, equilibrium manifolds, periodic or non-periodic solutions, and periodic solutions' extreme. Concerning the scenario of a directed torque on the major axis, a numerical solution for the problem is presented in addition to a simulation of the graphed results for the angular velocities' trajectories in various regions. Moreover, the influence of GM is examined for each case and a full modeling for the body's stability has been present. The exceptional impact of these results is evident in the development and assessment of systems involving asymmetric RBs, such as satellites and spacecraft. It may serve as a motivating factor to explore different angles within the GM in similar cases, thereby influencing various industries, including engineering and astrophysics applications.

3.
Sci Rep ; 13(1): 21430, 2023 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-38052918

RESUMO

This study examines the motion of a spring pendulum with two degrees-of-freedom (DOF) in a plane as a vibrating system, in which its pivot point is constrained to move along a Lissajous curve. In light of the system's coordinates, the governing equations of motion (EOM) are obtained utilizing the equations of Lagrange's. The novelty of this work is to use the approach of multiple scales (AMS), as a traditional method, to obtain novel approximate solutions (AS) of the EOM with a higher degree of approximation. These solutions have been compared with the numerical ones that have been obtained using the fourth-order Runge-Kutta algorithm (4RKA) to reveal the accuracy of the analytic solutions. According to the requirements of solvability, the emergent resonance cases are grouped and the modulation equations (ME) are established. Therefore, the solutions at the steady-state case are confirmed. The stability/instability regions are inspected using Routh-Hurwitz criteria (RHC), and examined in accordance with the steady-state solutions. The achieved outcomes, resonance responses, and stability areas are demonstrated and graphically displayed, to evaluate the positive effects of different values of the physical parameters on the behavior of the examined system. Investigating zones of stability/instability reveals that the system's behavior is stable for a significant portion of its parameters. A better knowledge of the vibrational movements that are closely related to resonance is crucial in many engineering applications because it enables the avoidance of on-going exposure to potentially harmful occurrences.

4.
Sci Rep ; 13(1): 20288, 2023 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-37985730

RESUMO

Due to the growing concentration in the field of the nonlinear oscillators (NOSs), the present study aims to use the general He's frequency formula (HFF) to examine the analytical representations for particular kinds of strong NOSs. Three real-world examples are demonstrated by a variety of engineering and scientific disciplines. The new approach is evidently simple and requires less computation than the other perturbation techniques used in this field. The new methodology that is termed as the non-perturbative methodology (NPM) refers to this innovatory strategy, which merely transforms the nonlinear ordinary differential equation (ODE) into a linear one. The method yields a new frequency that is equivalent to the linear ODE as well as a new damping term that may be produced. A thorough explanation of the NPM is offered for the reader's convenience. A numerical comparison utilizing the Mathematical Software (MS) is used to verify the theoretical results. The precise numeric and theoretical solutions exhibited excellent consistency. As is commonly recognized, when the restoration forces are in effect, all traditional perturbation procedures employ Taylor expansion to expand these forces and then reduce the complexity of the specified problem. This susceptibility no longer exists in the presence of the non-perturbative solution (NPS). Additionally, with the NPM, which was not achievable with older conventional approaches, one can scrutinize examining the problem's stability. The NPS is therefore a more reliable source when examining approximations of solutions for severe NOSs. In fact, the above two reasons create the novelty of the present approach. The NPS is also readily transferable for additional nonlinear issues, making it a useful tool in the fields of applied science and engineering, especially in the topic of the dynamical systems.

5.
Sci Rep ; 13(1): 11942, 2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37488150

RESUMO

A remarkable example of how to quantitatively explain the nonlinear performance of many phenomena in physics and engineering is the Van der Pol oscillator. Therefore, the current paper examines the stability analysis of the dynamics of ϕ6-Van der Pol oscillator (PHI6) exposed to exterior excitation in light of its motivated applications in science and engineering. The emphasis in many examinations has shifted to time-delayed technology, yet the topic of this study is still quite significant. A non-perturbative technique is employed to obtain some improvement and preparation for the system under examination. This new methodology yields an equivalent linear differential equation to the exciting nonlinear one. Applying a numerical approach, the analytical solution is validated by this approach. This novel approach seems to be impressive and promising and can be employed in various classes of nonlinear dynamical systems. In various graphs, the time histories of the obtained results, their varied zones of stability, and their polar representations are shown for a range of natural frequencies and other influencing factor values. Concerning the approximate solution, in the case of the presence/absence of time delay, the numerical approach shows excellent accuracy. It is found that as damping and natural frequency parameters increase, the solution approaches stability more quickly. Additionally, the phase plane is more positively impacted by the initial amplitude, external force, damping, and natural frequency characteristics than the other parameters. To demonstrate how the initial amplitude, natural frequency, and cubic nonlinear factors directly affect the periodicity of the resulting solution, many polar forms of the corresponding equation have been displayed. Furthermore, the stable configuration of the analogous equation is shown in the absence of the stimulated force.

6.
Sci Rep ; 13(1): 5570, 2023 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-37020045

RESUMO

The stability analysis of a rocking rigid rod is investigated in this paper using a time-delayed square position and velocity. The time delay is an additional safety against the nonlinearly vibrating system under consideration. Because time-delayed technologies have lately been the core of several investigations, the subject of this inquiry is extremely relevant. The Homotopy perturbation method (HPM) is modified to produce a more precise approximate outcome. Therefore, the novelty of the exciting paper arises from the coupling of the time delay and its correlation with the modified HPM. A comparison with the fourth-order Runge-Kutta (RK4) technique is employed to evaluate the precision between the analytical as well as the numerical solutions. The study allows for a comprehensive examination of the recognition of the outcome of the realistic approximation analytical methodology. For different amounts of the physical frequency and time delay factors, the time histories of the found solutions are depicted in various plots. These graphs are discussed in the context of the shown curves according to the relevant parameter values. The organized nonlinear prototype approach is examined by the multiple-time scale method up to the first approximation. The obtained results have periodic behavior and a stable manner. The current study makes it possible to carefully examine the findings arrived at by employing the analytical technique of practicable estimation. Additionally, the time delay performs as extra protection as opposed to the system potential for nonlinear oscillation.

7.
Sci Rep ; 13(1): 6507, 2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-37081048

RESUMO

This paper is concerned with a time-delayed controller of a damped nonlinear excited Duffing oscillator (DO). Since time-delayed techniques have recently been the focus of numerous studies, the topic of this investigation is quite contemporary. Therefore, time delays of position and velocity are utilized to reduce the nonlinear oscillation of the model under consideration. A much supplementary precise approximate solution is achieved using an advanced Homotopy perturbation method (HPM). The temporal variation of this solution is graphed for different amounts of the employed factors. The organization of the model is verified through a comparison between the plots of the estimated solution and the numerical one which is obtained utilizing the fourth order Runge-Kutta technique (RK4). The outcomes show that the improved HPM is appropriate for a variety of damped nonlinear oscillators since it minimizes the error of the solution while increasing the validation variety. Furthermore, it presents a potential model that deals with a diversity of nonlinear problems. The multiple scales homotopy technique is used to achieve an estimated formula for the suggested time-delayed structure. The controlling nonlinear algebraic equation for the amplitude oscillation at the steady state is gained. The effectiveness of the proposed controller, the time delays impact, controller gains, and feedback gains have been investigated. The realized outcomes show that the controller performance is influenced by the total of the product of the control and feedback gains, in addition to the time delays in the control loop. The analytical and numerical calculations reveal that for certain amounts of the control and feedback signal improvement, the suggested controller could completely reduce the system vibrations. The obtained outcomes are considered novel, in which the used methods are applied on the DO with time-delay. The increase of the time delay parameter leads to a stable case for the DO, which is in harmony with the influence of this parameter. This drawn curves show that the system reaches a stable fixed point which assert the presented discussion.

8.
Sci Rep ; 12(1): 18916, 2022 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-36344602

RESUMO

This paper studies the shortest time of slowing rotation of a free dynamically asymmetric rigid body (RB), analogous to Euler's case. This body is influenced by a rotatory moment of a tiny control torque with closer coefficients but not equal, a gyrostatic moment (GM) due to the presence of three rotors, and in the presence of a modest slowing viscous friction torque. Therefore, this problem can be regarded as a semi-optimal one. The controlling optimal decelerating law for the rotation of the body is constructed. The trajectories that are quasi-stationary are examined. The obtained new results are displayed to identify the positive impact of the GM. The dimensionless form of the regulating system of motion is obtained. The functions of kinetic energy and angular momentum besides the square module are drawn for various values of the GM's projections on the body's principal axes of inertia. The effect of control torques on the body's motion is investigated in a case of small perturbation, and the achieved results are compared with the unperturbed one. For the case of a lack of GM, the comparison between our results and those of the prior ones reveals a high degree of consistency, in which the deviations between them are examined. As a result, these outcomes generalized those that were acquired in previous studies. The significance of this research stems from its practical applications, particularly in the applications of gyroscopic theory to maintain the stability and determine the orientation of aircraft and undersea vehicles.

9.
Sci Rep ; 12(1): 16942, 2022 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-36210360

RESUMO

In this work, the influence of a gyrostatic moment vector (GMV) and the Newtonian field (NF) on the rotatory motion of a restricted rigid body (RB) according to disc case around a fixed point is examined. The basic equation of the body motion is used to get the regulating motion's system as well as the three available independent first integrals. The system's six equations and these integrals were reduced to two equations of a quasi-linear two-degrees-of-freedom autonomous system and one first integral. The disc has been presumed to be quickly rotating around one of the ellipsoid of inertia's main axis. Poincaré's method of small parameter (PMSP) is applied to acquire the periodic solutions of the controlling system of the body's motion. Euler's angles are utilized to characterize the body's configuration at any instant in which it is graphed, as well as the obtained solutions to explore the good action of the body's parameters on its motion. The phase plane graphs of these solutions are presented to examine their stabilities. The relevance of this work may be traced to its wide range of applications in fields as diverse as physics, engineering, and life sciences, including assembly and machine design.


Assuntos
Fenômenos Mecânicos , Rotação
10.
Sci Rep ; 12(1): 12628, 2022 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-35871675

RESUMO

The current work focuses on the motion of a simple pendulum connected to a wheel and a lightweight spring. The fundamental equation of motion is transformed into a complicated nonlinear ordinary differential equation under restricted surroundings. To achieve the approximate regular solution, the combination of the Homotopy perturbation method (HPM) and Laplace transforms is adopted in combination with the nonlinear expanded frequency. In order to verify the achievable solution, the technique of Runge-Kutta of fourth-order (RK4) is employed. The existence of the obtained solutions over the time, as well as their related phase plane plots, are graphed to display the influence of the parameters on the motion behavior. Additionally, the linearized stability analysis is validated to understand the stability in the neighborhood of the fixed points. The phase portraits near the equilibrium points are sketched.

11.
Pharmaceutics ; 13(7)2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34371789

RESUMO

Nanoparticle development demonstrates use in various physicochemical, biological, and functional properties for biomedical applications, including anti-cancer applications. In the current study, a cancer therapeutic conjugate was produced consisting of tamoxifen (TAM) and resveratrol (RES) by layer-by-layer (LbL) nanoparticles based on lipid-based drug delivery systems and liquid crystalline nanoparticles (LCNPs) coated with multiple layers of positively charged chitosan and negatively charged hyaluronic acid for the evaluation of biocompatibility and therapeutic properties against cancer cells. Multiple techniques characterized the synthesis of TAM/RES-LbL-LCNPs, such as Fourier-transform infrared spectroscopy (FTIR), X-ray crystallography (XRD), Zeta potential analysis, particle size analysis, Field Emission Scanning Electron Microscope (FESEM), and Transmission electron microscopy (TEM). The in vitro cytotoxic effects of TAM/RES-LbL-LCNPs were investigated against human breast cancer cell line, Michigan Cancer Foundation-7 (MCF-7), and human triple-negative breast cancer cell line, Centre Antoine Lacassagne-51 (CAL-51), using various parameters. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay confirmed that the treatment of cells with TAM/RES-LbL-LCNPs caused a reduction in cell proliferation, and no such inhibition was observed with human normal liver cell line: American Type Culture Collection Cell Line-48 (WRL-68 [ATCC CL-48]). Fluorescent microscopy examined the ability of Fluorescein isothiocyanate (FITC) to bind to TAM/RES-LbL-LCNPs along with their cellular uptake. Apoptosis determination was performed using hematoxylin-eosin and acridine orange-propidium iodide double staining. The expression of P53 and caspase-8 was analyzed by flow cytometry analysis. An in vivo study determined the toxicity of TAM/RES-LbL-LCNPs in mice and assessed the functional marker changes in the liver and kidneys. No significant statistical differences were found for the tested indicators. TAM/RES-LbL-LCNP treatment showed no apparent damages or histopathological abnormalities in the heart, lung, liver, spleen, and kidney histological images. The current findings observed for the first time propose that TAM/RES-LbL-LCNPs provide a new and safer method to use phytochemicals in combinatorial therapy and provide a novel treatment approach against breast cancers.

12.
Nanomedicine (Lond) ; 16(22): 1937-1961, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34431317

RESUMO

Aims: To evaluate the anti breast-cancer activity, biocompatibility and toxicity of poly(d,l)-lactic-co-glycolic acid (PLGA)-encapsulated quercetin nanoparticles (Q-PLGA-NPs). Materials & methods: Quercetin was nano-encapsulated by an emulsion-diffusion process, and the nanoparticles were fully characterized through Fourier transform infrared spectroscopy, x-ray diffractions, FESEM and zeta-sizer analysis. Activity against CAL51 and MCF7 cell lines were assessed by DNA fragmentation assays, fluorescence microscopy, and acridine-orange, and propidium-iodide double-stainings. Biocompatibility towards red blood cells and toxicity towards mice were also explored. Results: The Q-PLGA-NPs exhibited apoptotic activity against the cell lines. The murine in vivo studies showed no significant alterations in the liver and kidney's functional biomarkers, and no apparent abnormalities, or tissue damages were observed in the histological images of the liver, spleen, lungs, heart and kidneys. Conclusion: The study established the preliminary in vitro efficacy and in vivo safety of Q-PLGA-NPs as a potential anti-breast cancer formulation.


Lay abstract Quercetin is a flavonoid, a type of chemical, antioxidant in nature, found in many fruits and vegetables. It is known to have anticancer properties. In this study, quercetin was encased into nano-sized particles of biologically compatible and bio-degradable synthetic polymer, named PLGA (poly-[D,L]-lactic-co-glycolic acid). The effects of the quercetin nanoparticles/nano-quercetin were tested against two types of breast cancer cell lines in the laboratory. The quercetin-loaded nanoparticles were able to kill the breast cancer cells, suggesting they could be able to kill the cancer cells in the body. Also, when given to mice, the quercetin nanoparticles did not appear to damage any organ, or change the functions of the liver, and kidneys, thereby suggesting that they are not toxic. Further work is required to assess how well they could be used to treat breast cancer in people.


Assuntos
Nanopartículas , Neoplasias , Animais , Apoptose , Expressão Gênica , Humanos , Ácido Láctico , Células MCF-7 , Camundongos , Quercetina/farmacologia
14.
Ann R Coll Surg Engl ; 102(4): 243-247, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31918554

RESUMO

INTRODUCTION: Since the seminal works by Singh and Blandy in the 1970s, the management of staghorn stones has almost exclusively involved surgical intervention. In contrast, a more recent study found that conservative management was not as unsafe as previously believed. The present review sought to examine the available literature to understand the implications of a conservative strategy. METHODS: A systematic search of the literature was carried out using MEDLINE®, Embase™ and the Cochrane Central Register of Controlled Trials. All papers looking at management of staghorn calculi were reviewed and studies with a conservative management arm were identified. Outcomes of interest were recurrent or severe urinary tract infections, progressive renal deterioration, dialysis requirements, morbidity and disease specific mortality. Owing to the lack of relevant data, a descriptive review was carried out. RESULTS: Our literature search yielded 10 suitable studies involving a total of 304 patients with staghorn stones managed conservatively. Progressive renal deterioration occurred in 0-100% of cases (mean 27.5%) with a higher rate among bilateral staghorn sufferers (44% vs 9%). Dialysis was required in 9% of patients (20% bilateral, 6% unilateral). The mean rate of severe infection was 8.7% and recurrent urinary tract infections occurred in as high as 50% of cases (80% bilateral, 41% unilateral). Disease specific mortality ranged from 0% to 67% (mean 20.5%). CONCLUSIONS: It appears that conservative management of staghorn calculi is not as unsafe as previously thought and selection of patients with unilateral asymptomatic stones with minimal infection should be considered.


Assuntos
Tratamento Conservador/efeitos adversos , Insuficiência Renal/epidemiologia , Cálculos Coraliformes/terapia , Infecções Urinárias/epidemiologia , Tratamento Conservador/métodos , Humanos , Diálise Renal/estatística & dados numéricos , Insuficiência Renal/etiologia , Insuficiência Renal/terapia , Índice de Gravidade de Doença , Cálculos Coraliformes/complicações , Cálculos Coraliformes/mortalidade , Infecções Urinárias/diagnóstico , Infecções Urinárias/etiologia
15.
Appl Radiat Isot ; 135: 135-141, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29413828

RESUMO

A neutron irradiation facility consisting of six 241Am-Be neutron sources of 30 Ci total activity and 6.6 × 107 n/s total neutron yield is designed. The sources are embedded in a cubic paraffin wax, which plays a dual role as both moderator and reflector. The sample passage and irradiation channel are represented by a cylindrical path of 5 cm diameter passing through the facility core. The proposed design yields a high degree of space symmetry and thermal neutron homogeneity within 98% of flux distribution throughout the irradiated spherical sample of 5 cm diameter. The obtained thermal neutron flux is 8.0 × 104 n/cm2.s over the sample volume, with thermal-to-fast and thermal-to-epithermal ratios of 1.20 and 3.35, respectively. The design is optimized for maximizing the thermal neutron flux at sample position using the MCNP-5 code. The irradiation facility is supposed to be employed principally for neutron activation analysis.

16.
Biotechnol Prog ; 34(1): 218-230, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28960911

RESUMO

Copper oxide nanoparticles (CUNPs) were synthesized using Olea europaea leaf extract as reducing and protecting agent. The formation of nanoparticles was observed through a color change from yellowish to brownish black. The CUNPs were confirmed with UV-Vis spectrophotometer, which revealed a peak absorbance at 289 nm. The synthesized CUNPs were characterized by XRD, FTIR, SEM, and TEM. The XRD pattern revealed that CUNPs were crystalline in nature with a diameter around 20 nm. FTIR spectral analysis showed that CUNPs were capped with plant constituents. From SEM and TEM analyses, the CUNPs were generally found to be spherical in shape, and the size range was 20-50 nm. Free radical scavenging potential of CUNPs against DPPH was confirmed by its stable antioxidant effects. In addition, the toxicity of CUNPs in mice was also assessed by body weight and weights of liver, kidneys, spleen, and thymus. The immune response in mice was signaled through an obvious change in spleen and thymus index, with a decrease of ADA enzyme activity in serum, spleen, and thymus after CUNPs treatment. The CUNPs were found to exert cell growth arrest against AMJ-13 and SKOV-3 cancer cells in a dose-dependent manner and induce cell death by apoptosis. Less significant cytotoxic effect was observed in normal dermal fibroblast cells. These findings suggest that CUNPs may have the potential to be anticancer agents. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:218-230, 2018.


Assuntos
Cobre/química , Nanopartículas Metálicas/química , Olea/química , Extratos Vegetais/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Sequestradores de Radicais Livres/química , Química Verde , Humanos , Camundongos , Extratos Vegetais/síntese química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Espectroscopia de Infravermelho com Transformada de Fourier
17.
Artif Cells Nanomed Biotechnol ; 46(6): 1215-1229, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28826240

RESUMO

Magnetic iron oxide nanoparticles (MNPs) were synthesized using Albizia adianthifolia leaf extract as reducing and protecting agent. Colour changing, UV-Vis spectrum, X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) confirmed the biosynthesis and characterization of MNPs. The XRD pattern revealed that MNPs are crystalline in nature. FT-IR spectral analysis showed that MNPs was capped with plant constituents. From SEM analysis, the MNPs were generally found to be spherical in shape and the size was ranged 32-100 nm. Free radical scavenging potentials of the MNPs against DPPH were confirmed based on its stable anti-oxidant effects. The synthesized MNPs were used to capture Staphylococcus aureus under the magnetic field effect. Further, it was observed that the MNPs are able to exert cytotoxic effect towards human breast (AMJ-13) and (MCF-7) cancer cells. The anti-proliferative effect of this treatment is due to cell death and inducing apoptosis. Mitochondrial membrane potential, acridine orange-propidium iodide staining assays as well as single cell and DNA gel electrophoresis analyses indicated that MNPs induce cell death only by apoptosis. The findings of present study suggest that the MNPs might be used for medicinal applications particularly for cancer therapeutics.


Assuntos
Albizzia/química , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Dano ao DNA/efeitos dos fármacos , Compostos Férricos/química , Nanopartículas de Magnetita/toxicidade , Extratos Vegetais/química , Linhagem Celular Tumoral/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Compostos Férricos/farmacologia , Humanos , Células MCF-7 , Nanopartículas de Magnetita/química , Nanopartículas de Magnetita/ultraestrutura , Tamanho da Partícula , Extratos Vegetais/farmacologia , Folhas de Planta/química
18.
Saudi J Kidney Dis Transpl ; 28(5): 1064-1068, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28937064

RESUMO

Nephrocalcinosis (NC) is defined as deposition of calcium crystals in the renal parenchyma and tubules. This is a retrospective review of all the data of 63 children presented to Pediatric Nephrology Clinic at King Hussein Medical Center (KHMC) over a 15-year period with bilateral NC. We determine their causes, clinical presentation and evaluate their growth and renal function during their follow-up. Thirty-five (55.5%) cases were males and 28 (44.5%) were females. The median (range) age at presentation was four (2-192) months. The most common leading cause to NC was hereditary tubulopathy in 48% followed by hyperoxaluria in 35%. The cause of NC remained unknown in 3% and Vitamin D excess accounts for 5% of the cases. The most presenting symptom was a failure to thrive (68%) and the second most common symptom was abdominal pain and recurrent urinary tract infection was found in 40%, polyuria and polydipsia were found in 32% of cases, and 16% of cases were diagnosed incidentally. At a median follow-up of 38 (14-200) months, estimated glomerular filtration rate had decreased from 84.0 (42-110) mL/min per 1.73 m2 body surface area to 68.2 (10-110) mL/min/1.73 m2 body surface (P = 0.001). This study illustrated the need for a national registry of rare renal diseases to help understand the causes of these conditions in our populations and provide support to affected patients and their families.


Assuntos
Nefrocalcinose/epidemiologia , Nefrocalcinose/terapia , Dor Abdominal/epidemiologia , Dor Abdominal/terapia , Adolescente , Fatores Etários , Criança , Pré-Escolar , Insuficiência de Crescimento/epidemiologia , Insuficiência de Crescimento/terapia , Feminino , Taxa de Filtração Glomerular , Humanos , Lactente , Rim/fisiopatologia , Masculino , Nefrocalcinose/diagnóstico , Nefrocalcinose/fisiopatologia , Polidipsia/epidemiologia , Polidipsia/terapia , Poliúria/epidemiologia , Poliúria/terapia , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento , Infecções Urinárias/epidemiologia , Infecções Urinárias/terapia
19.
Ann R Coll Surg Engl ; 98(8): e184-e185, 2016 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27502347

RESUMO

Angiosarcoma is an extremely rare vascular malignancy with a 1-year survival rate of 50%, regardless of tumour origin. Distant metastases are common and occur in the lungs, bone, lymph nodes and soft tissues. The majority of patients with angiosarcoma present with localised disease, although 25-45% have distant metastases at presentation. There are few reported cases of angiosarcomas of the bladder and we report the second case in the literature of primary angiosarcoma of the ureter. We suggest that, in atypical manifestations of suspected urothelial malignancy, the multidisciplinary team considers the possibility of rarer, aggressive tumours early. This may influence clinical decision making towards offering radical treatments earlier, before it is too late to do so owing to aggressive oncological behaviour.


Assuntos
Hemangiossarcoma/diagnóstico , Neoplasias Ureterais/diagnóstico , Idoso , Hemangiossarcoma/patologia , Hemangiossarcoma/cirurgia , Humanos , Masculino , Ureter/patologia , Ureter/cirurgia , Neoplasias Ureterais/patologia , Neoplasias Ureterais/cirurgia
20.
J Obstet Gynaecol ; 35(8): 832-4, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25710101

RESUMO

Transabdominal sonoelastography (TASE) is a new imaging technique that maps the elastic properties of soft tissue. We evaluated 34, consecutive women with suspected scar endometrioma using standard B-mode ultrasound and elastography. Twenty-three women (23/34) underwent surgical excision and had the diagnosis confirmed by histopathology. All endometriomas (23 patients) in B-mode imaging appeared as hypoechoic masses along the line of a previous caesarean section incision and the outer borders were difficult to define precisely. By TASE, the endometrioma presented a typical blue-green-red appearance and the outer borders were clearly defined. (red and green area corresponds with the central hypoechoic soft areas). Strain ratios varied from 0.02 to 0.75. Real-time TASE is a simple, useful technique in confirming a clinical diagnosis of endometrioma in a caesarean section scar. Compared with B-mode ultrasound, it provides additional, preoperative information about the extent of the lesion that may be helpful to the surgeon.


Assuntos
Cesárea/efeitos adversos , Técnicas de Imagem por Elasticidade , Endometriose/diagnóstico por imagem , Adulto , Endometriose/etiologia , Feminino , Humanos , Projetos Piloto , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...