Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 25
Filtrar
1.
Nature ; 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38898283

RESUMEN

Glassy polymers are generally stiff and strong yet have limited extensibility1. By swelling with solvent, glassy polymers can become gels that are soft and weak yet have enhanced extensibility1-3. The marked changes in properties arise from the solvent increasing free volume between chains while weakening polymer-polymer interactions. Here we show that solvating polar polymers with ionic liquids (that is, ionogels4,5) at appropriate concentrations can produce a unique class of materials called glassy gels with desirable properties of both glasses and gels. The ionic liquid increases free volume and therefore extensibility despite the absence of conventional solvent (for example, water). Yet, the ionic liquid forms strong and abundant non-covalent crosslinks between polymer chains to render a stiff, tough, glassy, and homogeneous network (that is, no phase separation)6, at room temperature. Despite being more than 54 wt% liquid, the glassy gels exhibit enormous fracture strength (42 MPa), toughness (110 MJ m-3), yield strength (73 MPa) and Young's modulus (1 GPa). These values are similar to those of thermoplastics such as polyethylene, yet unlike thermoplastics, the glassy gels can be deformed up to 670% strain with full and rapid recovery on heating. These transparent materials form by a one-step polymerization and have impressive adhesive, self-healing and shape-memory properties.

2.
Data Brief ; 53: 110241, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38439993

RESUMEN

The urban building stock dataset consists of synthetic input and output data for the energy simulation of one million buildings. The dataset consists of four different residential types, namely: terraced, detached, semi-detached, and bungalow. Constructing this buildings dataset requires conversion, categorization, extraction, and analytical processes. The dataset (in .csv) format comprises 19 input parameters, including advanced features such as HVAC system parameters, building fabric (walls, roofs, floors, door, and windows) U-values, and renewable system parameters. The primary output parameter in the dataset is Energy Use Intensity (EUI in kWh/(m2*year)), along with Energy Performance Certificate (EPC) labels categorized on an A to G rating scale. Additionally, the dataset contains end-use demand output parameters for heating and lighting, which are crucial output parameters. jEPlus, a parametric tool, is coupled with EnergyPlus and DesignBuilder templates to facilitate physics-based parametric simulations for generating the dataset. The dataset can be a valuable resource for researchers, practitioners, and policymakers seeking to enhance sustainability and efficiency in urban building environments. Furthermore, dataset holds immense potential for future research in the field of building energy analysis and modeling.

3.
ACS Appl Mater Interfaces ; 16(8): 10931-10941, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38377555

RESUMEN

The fluid nature of liquid metals combined with their ability to form a solid native oxide skin enables them to be patterned in ways that would be challenging for solid metals. The present work shows a unique way of patterning liquid metals by injecting liquid metals into a mold. The mold contains a nonstick coating that enables the removal of the mold, thereby leaving just the liquid metal on the target substrate. This approach offers the simplicity and structural control of molding but without having the mold become part of the device. Thus, the metal can be encapsulated with very soft polymers that collapse if used as microchannels. The same mold can be used multiple times for high-volume patterning of liquid metal. The injection molding method is rapid and reliably produces structures with complex geometries on both flat and curved surfaces. We demonstrate the method by fabricating an elastomeric Joule heater and an electroadhesive soft gripper to show the potential of the method for soft and stretchable devices.

5.
ACS Sens ; 7(10): 3169-3180, 2022 10 28.
Artículo en Inglés | MEDLINE | ID: mdl-36250738

RESUMEN

Easy sample collection, physiological relevance, and ability to noninvasively and longitudinally monitor the human body are some of the key attributes of wearable sweat sensors. Examples typically include reversible sensors or an array of single-use sensors embedded in specialized microfluidics for temporal analysis of sweat. However, evolving this field to a level that truly represents "lab-on-skin" technology will require the incorporation of advanced functionalities that give the user the freedom to (1) choose the precise time for performing sample analysis and (2) select sensors from an array embedded within the device for performing condition-specific sample analysis. Here, we introduce new concepts in wearable microfluidic platforms that offer such capabilities. The described technology involves a series of finger-actuated pumps, valves, and sensors incorporated within soft, wearable microfluidics. The incoming sweat collects in the inlet chamber and can be analyzed by the user at the time of their choosing. On-demand sweat analyte assessment is achieved by pulling a thin tab to activate a pump which opens a valve and allows the pooled sweat to enter a chamber embedded with sensors for the desired analytes. The article describes a thorough characterization of the platform that demonstrates the robustness of the pumping, valving, and sensing aspects of the device under conditions mimicking real-life scenarios. A two-day-long human pilot study validates the system and illustrates the device's ability to offer on-demand, longitudinal, and multianalyte sensing. Our work represents the first example of a wearable system with such on-demand sensing capabilities and opens exciting avenues in sweat sensing for acquiring new insights into human physiology.


Asunto(s)
Sudor , Dispositivos Electrónicos Vestibles , Humanos , Microfluídica , Cuerpo Humano , Proyectos Piloto
6.
Clin Case Rep ; 10(10): e6352, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36276900

RESUMEN

Mucormycosis is an opportunistic infection that has become a serious concern as a result of the immunosuppressive drugs used during COVID-19. In this report, we describe two cases of rhino-orbital-cerebral mucormycosis with neurological presentation and ophthalmologic problems accompanied by a history of COVID-19 and diabetes.

7.
Data Brief ; 42: 108194, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35515985

RESUMEN

Two hundred people of the line (new and experienced) and staff (new and experienced) armed forces consisted of the samples. Using a flexible ruler, spinal curves (thoracic kyphosis and lumbar lordosis) were measured. The biggest kyphosis and lordosis values were seen in experienced staff and experienced line groups and the smallest kyphosis and lordosis values were seen in new staff and experienced staff groups, respectively. One-way repeated-measures analysis of variance (ANOVA) was carried out on the thoracic kyphosis and lumbar lordosis measures of the line and the staff groups to assess differences between groups and the post hoc test was carried out to define the group that was significantly distinct from the others.

8.
Nutr J ; 21(1): 28, 2022 05 12.
Artículo en Inglés | MEDLINE | ID: mdl-35546233

RESUMEN

BACKGROUND: Chronic low back pain (LBP) is the most common musculoskeletal pain that affects a person's daily activities. This present study aimed at evaluating the relationship between major dietary pattern and Chronic LBP. METHODS: This cross-sectional analysis was examined 7686 Kurdish adults. The RaNCD cohort study physician diagnosed chronic LBP. Dietary patterns were derived using principal component analysis. The three identified dietary patterns derived were named: 1) the vegetarian diet included vegetables, whole grain, legumes, nuts, olive, vegetable oil, fruits, and fruit juice; 2) high protein diet related to higher adherence to red and white meat, legumes, nuts, and egg; and 3) energy-dense diet characterized with higher intake of salt, sweet, dessert, hydrogenated fat, soft drink, refined grain, tea, and coffee. Dietary pattern scores were divided into tertiles. Binary logistic regression in crude, adjusted odds ratios (OR) and 95% confidence intervals (CI) were used to determine this association. RESULTS: Twenty-two per cent of participants had chronic LBP. Higher adherence to high protein dietary pattern was inversely associated with chronic LBP in crude (OR: 0.79, 95% CI: 0.69-0.9) and adjusted model (for age, sex, smoking, drinking, diabetes, physical activity, body mass index, and waist circumference) (OR: 0.84, 95% CI: 0.72-0.97). In addition, after controlling for the mentioned potential confounders, participants in the highest category of energy dense diet were positively associated with chronic LBP compared with those in the lowest category (OR: 1.13, 95% CI: 1.01-1.32). CONCLUSIONS: Higher adherence to the high protein diet was inversely related to chronic LBP prevalence. In addition, we found that following energy dense diet was positively associated with chronic LBP.


Asunto(s)
Dolor de la Región Lumbar , Adulto , Estudios de Cohortes , Estudios Transversales , Dieta , Conducta Alimentaria , Frutas , Humanos , Dolor de la Región Lumbar/epidemiología , Verduras
9.
Nat Mater ; 21(3): 359-365, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35190655

RESUMEN

Ionogels are compelling materials for technological devices due to their excellent ionic conductivity, thermal and electrochemical stability, and non-volatility. However, most existing ionogels suffer from low strength and toughness. Here, we report a simple one-step method to achieve ultra-tough and stretchable ionogels by randomly copolymerizing two common monomers with distinct solubility of the corresponding polymers in an ionic liquid. Copolymerization of acrylamide and acrylic acid in 1-ethyl-3-methylimidazolium ethyl sulfate results in a macroscopically homogeneous covalent network with in situ phase separation: a polymer-rich phase with hydrogen bonds that dissipate energy and toughen the ionogel; and an elastic solvent-rich phase that enables for large strain. These ionogels have high fracture strength (12.6 MPa), fracture energy (~24 kJ m-2) and Young's modulus (46.5 MPa), while being highly stretchable (~600% strain) and having self-healing and shape-memory properties. This concept can be applied to other monomers and ionic liquids, offering a promising way to tune ionogel microstructure and properties in situ during one-step polymerization.


Asunto(s)
Líquidos Iónicos , Conductividad Eléctrica , Geles/química , Enlace de Hidrógeno , Líquidos Iónicos/química , Polímeros
10.
Heliyon ; 7(9): e08062, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34622066

RESUMEN

Quantitative estimation of mechanical characteristics of soils and determination of their behavior using in-situ experiments have always been one of the main concerns of geotechnical engineers. So far, various methods have been introduced to achieve this goal, among which the Dynamic Cone Penetrometer (DCP) test has become more popular as one of the most accurate and efficient methods. Therefore, in this study, an attempt was made to examine the correlation between different soil parameters by performing DCP test along with a series of conventional tests including Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests on marl soil samples containing 2, 5, 8% lime at 1, 7 and 15 curing days. Furthermore, since the subgrade reaction coefficient (Ks) is needed in the design of pavements and their underlying materials, Plate Load Test (PLT) was performed to determine Ks. The results showed that the addition of lime up to 5% increased UCS, CBR and Ks and decreased dynamic penetrometer index (DPI) of marl soil samples. Further addition of lime had a negative effect on the mechanical characteristics of the samples. Moreover, using the equations obtained from the correlations in this study, strength characteristics and subgrade reaction coefficient of the stabilized marl soil can be estimated by knowing the DPI of the samples. The results of this study showed that the use of the DCP test as a cheap and easy-to-use method can provide a comprehensive view of soil behavior in civil engineering projects with an acceptable coefficient of determination to geotechnical engineers.

11.
Front Hum Neurosci ; 15: 620439, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33994974

RESUMEN

Neurofibromatosis type 1 (NF1) is associated with peripheral and central nervous system tumors. It is noteworthy that the regions in which these tumors frequently arise are the optic pathways (OPs) and the brainstem. Thus, we decided to trace the procedure of diffusion Magnetic Resonance Imaging (dMRI) alterations along with Short-Wavelength Automated Perimetry (SWAP) examinations of the OPs after surgery and chemotherapy over 1 year, which enabled us to evaluate chemotherapy's efficacy in an NF1 patient with an OP tumor. In this study, a 25-year-old woman with NF1 and left optic radiation (OR) glioma underwent surgery to remove the glioma. Immunohistochemistry (IHC) revealed a Pilocytic Astrocytoma (PA) WHO grade I. Post-operation chemotherapy done using nine treatment cycles of administering Temozolomide (TMZ) for 5 days every 4 weeks. Applying the region of interest (ROI) differential tractography method and SWAP four times every 3 months allowed us to follow the patient's visual acuity alterations longitudinally. The differential deterministic tractography method and statistical analyses enabled us to discover the white matter (WM) tracts anisotropy alterations over time. Furthermore, statistical analyses on the SWAP results along time illustrated possible alterations in visual acuity. Then, we could compare and associate the findings with the SWAP examinations and patient symptoms longitudinally. Statistical analyses of SWAP tests revealed a significant improvement in visual fields, and longitudinal differential tractography showed myelination and dense axonal packing in the left OR after 1 year of treatment. In this study, we examined an old hypothesis suggesting that chemotherapy is more effective than radiotherapy for NF1 patients with OP gliomas (OPGs) because of the radiation side effects on the visual field, cognition, and cerebrovascular complications. Our longitudinal clinical case study involving dMRI and SWAP on a single NF1-OPG patient showed that chemotherapy did not suppress the OP myelination over time. However, it should be noted that this is a clinical case study, and, therefore, the generalization of results is limited. Future investigations might focus on genetic-based imaging, particularly in more cases. Further, meta-analyses are recommended for giving a proper Field Of View (FOV) to researchers as a subtle clue regarding precision medicine.

12.
Placenta ; 106: 49-57, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33640737

RESUMEN

INTRODUCTION: Gestational diabetes mellitus (GDM) is a metabolic syndrome among pregnant mothers that increases the risk of developing growth disorders in the fetus and the placenta. Adiponectin is an adipokine, which plays a central role in the regulation of glucose and lipid metabolism, energy homeostasis, and insulin resistance in various tissues. Quercetin is a natural flavonoid with beneficial effects in the diabetic animal model, but data related to its effect on histological change and adiponectin system in the placenta of GDM are limited. In the current study, some histological changes and expression of adiponectin and its two receptors in the placenta of rats with GDM were investigated. METHODS: This study was carried out on placentas from the rodent model. To induce GDM, female rats were treated with a single dose of STZ. Placenta tissue was harvested and stained by PAS method. Protein and mRNA levels of adiponectin and its two receptors were assessed by immunohistochemistry and Real time PCR analysis, respectively. RESULTS: The results showed the increased number of glycogen cells and thickness of the labyrinth interhemal membrane (LIM) in the embryonic part of the placenta in diabetic rats, while the use of quercetin significantly prevented their increase in diabetic rats. Treatment of the diabetic group with quercetin caused significantly increased adiponectin expression and decreased its receptors.The immunohistochemical study revealed the expression of AdipoR2 in the cytoplasm of syncytiotrophoblast and cytotrophoblast cells. DISCUSSION: The results indicated that quercetin in pregnant diabetic rats could attenuate the histological abnormalities and improved adiponectin system dysregulation in the placenta.


Asunto(s)
Adiponectina/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Gestacional/metabolismo , Placenta/efectos de los fármacos , Quercetina/farmacología , Receptores de Adiponectina/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Adiponectina/genética , Animales , Femenino , Masculino , Placenta/metabolismo , Embarazo , Ratas , Ratas Wistar , Receptores de Adiponectina/genética
13.
Iran J Pharm Res ; 19(2): 115-126, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33224216

RESUMEN

Biosurfactants, the microbial originated surface active agents, can modify the physicochemical properties of surfaces and reduce the bacterial adhesion via changing bacterial adhesion interactions on surfaces. They were also able to block oxidative chain reactions and might show antioxidant properties. The goal of this study was to evaluate the antioxidant and antibiofilm activities of biosurfactants which were derived from two autochthonous biosurfactant-producing strains, Bacillus amyloliquefaciens NS6 (surfactin), and Pseudomonas aeruginosa MN1 (rhamnolipids). Their antioxidant activities were determined by ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods. Ferric thiocyanate (FTC) assay was used for determination of their lipid peroxidation inhibition capacity. Their effect to reduce the adhesion of Streptococcus mutans on polystyrene surfaces and disruption of its pre-formed biofilms were also investigated. Our results indicated that surfactin showed higher antioxidant activity than rhamnolipids and showed relatively similar efficiency to BHA that suggests it as a good alternative for synthetic antioxidants. In other hand, rhamnolipid conditioned surfaces showed higher antiadhesive and antibiofilm activity in comparison with surfactin treated surfaces.

14.
BMC Musculoskelet Disord ; 21(1): 686, 2020 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-33066753

RESUMEN

BACKGROUND: Musculoskeletal disorders can reduce the quality of life and work capacity. The study assessed handgrip strength (HGS) in relation to low back pain and arthralgia in Kurdish men. METHODS: This cross-sectional study was conducted using data from Ravansar non-communicable diseases (RaNCD) cohort study on 2164 men aged 35-65 years. HGS was measured using a hand-held hydraulic handgrip dynamometer. Low back pain, arthralgia, and joint stiffness were evaluated by the RaNCD cohort study physician using a standard questionnaire. RESULTS: The results showed that 21.39 and 24.58% of studied participants had low back pain and arthralgia, respectively. Among the participants with low back pain, 14.5% had back stiffness, and among those with arthralgia, 12.8% had joint stiffness. The mean of HGS in participants with arthralgia and back & joint stiffness was significantly less than those without these disorders (P < 0.001, P = 0.05, and P = 0.005, respectively). Multiple-adjusted OR and 95% confidence intervals (CI) for arthralgia and back and joint stiffness across muscle strength showed the HGS increase to be associated with a lower risk of arthralgia and back &joint stiffness, but not low back pain. CONCLUSIONS: Higher HGS was associated with a lower risk of arthralgia and back & joint stiffness. However, there was no association between HGS and low back pain. Exercise and adherence to proper nutrition are suggested to enhance muscle strength in order to reduce musculoskeletal pain.


Asunto(s)
Fuerza de la Mano , Enfermedades no Transmisibles , Adulto , Anciano , Artralgia/diagnóstico , Artralgia/epidemiología , Estudios de Cohortes , Estudios Transversales , Humanos , Masculino , Persona de Mediana Edad , Calidad de Vida
18.
J Perianesth Nurs ; 34(6): 1232-1240, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31324446

RESUMEN

PURPOSE: The present study aimed to evaluate the effect of Benson's muscle relaxation on postoperative spinal anesthesia-induced pain. DESIGN: Randomized clinical trial. METHODS: Sixty-four patients were randomly assigned to intervention and control groups. Benson's muscle relaxation was performed on the intervention group for 10 to 20 minutes based on the patients' tolerance. Before and after the intervention, the two groups were assessed using the visual analog scale and compared. SPSS version 23 was used to analyze data. FINDINGS: The mean pain score in the control group before and after the intervention was 5.34 and 5.62, respectively (P < .003), and in the intervention group, 5.28 and 4.03, respectively (P < .001). CONCLUSION: Benson's relaxation technique effectively influenced the intensity of postoperative spinal anesthesia-induced pain. Therefore, it can be used by nurses as a safe, simple, and inexpensive nonmedicinal treatment method to relieve spinal anesthesia-induced pain.


Asunto(s)
Anestesia Raquidea/efectos adversos , Manejo del Dolor/métodos , Dolor Postoperatorio/etiología , Dolor Postoperatorio/terapia , Terapia por Relajación/métodos , Femenino , Humanos , Masculino
19.
J Pharm Sci ; 106(12): 3623-3630, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28826879

RESUMEN

The objective of this work was to prepare the streptokinase (SK) entrapped in chitosan nanoparticles (CS NPs) using bulk mixing (BM) and microfluidic (MF) techniques. The physicochemical properties of the samples were characterized by means of scanning electron microscopy and dynamic light scattering analysis for optimizing CS and SK solution concentrations as well as pH values. The obtained results showed that CS NPs fabricated using MF chip have the most uniform morphology, spherical shape, and average diameter of 67 ± 13 nm along with a narrow polydispersity. Conversely, the NP samples prepared via BM method have an irregular and disordered morphology as well as a broad distribution in their particle size (452 ± 300 nm). The in vitro drug release from microfluidically generated CS NPs depicted the controlled release of SK without plateau regime compared to those samples prepared using BM method during 48 h. Also, the drug release kinetic followed Higuchi model which revealed that the Fickian diffusion was the predominant mechanism. Subsequently, in in vivo animal model test, the performance of SK in blood plasma exhibited higher amidolytic activity for SK entrapped in CS NP samples fabricated via MF technique compared to those NPs prepared using BM and also SK alone.


Asunto(s)
Quitosano/química , Nanopartículas/química , Estreptoquinasa/química , Animales , Portadores de Fármacos/química , Liberación de Fármacos , Masculino , Microfluídica/métodos , Microscopía Electrónica de Rastreo/métodos , Tamaño de la Partícula , Ratas , Ratas Wistar , Terapia Trombolítica/métodos
20.
Int J Biol Macromol ; 99: 433-442, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28274863

RESUMEN

The aim of this work was to provide a microfluidic-aided fabrication of nanoparticles based on chitosan/poly(N-isopropylacrylamide-co-acrylic acid)/cellulose laurate [CS/P(NIPAAm-co-AAc/CL] blend for transdermal multidrug delivery applications. The scanning electron microscopy (SEM) and dynamic light scattering (DLS) results showed that the diameter sizes of samples were in the range from 200 to 300nm along with a narrow size distribution. Also, the CS-based nanoparticles containing tretinoin and clindamycin phosphate prepared using microfluidic technique exhibited a sustained control release of the drugs as well as minimum inhibitory and bactericidal concentrations compared to the samples fabricated via bulk mixing method. The thermal stability of the drugs loaded nanoparticles revealed a reduction in degradation for those fabricated by using microfluidic technique at 45°C for one month. Afterward, the in vivo assessments confirmed that by applying the microfluidically generated nanoparticles containing two drugs, a declined superficial reddening (erythema) and suitable transdermal permeation as well as residency were happened with respect to the those samples prepared via bulk mixing method and also the drugs solution alone. Finally, these CS-based nanoparticles showed sufficient potential used for transdermal multidrug delivery applications.


Asunto(s)
Quitosano/química , Portadores de Fármacos/química , Microfluídica , Nanopartículas/química , Nanotecnología , Piel/metabolismo , Acrilamidas/química , Animales , Celulosa/química , Liberación de Fármacos , Estabilidad de Medicamentos , Tamaño de la Partícula , Permeabilidad , Polímeros/química , Conejos , Temperatura
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...