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1.
Proc Natl Acad Sci U S A ; 116(28): 13867-13872, 2019 07 09.
Artículo en Inglés | MEDLINE | ID: mdl-31239344

RESUMEN

Small variations in the primary amino acid sequence of extracellular matrix proteins can have profound effects on the biomineralization of hard tissues. For example, a change in one amino acid within the amelogenin protein can lead to drastic changes in enamel phenotype, resulting in amelogenesis imperfecta, enamel that is defective and easily damaged. Despite the importance of these undesirable phenotypes, there is very little understanding of how single amino acid variation in amelogenins can lead to malformed enamel. Here, we aim to develop a thermodynamic understanding of how protein variants can affect steps of the biomineralization process. High-resolution, in situ atomic force microscopy (AFM) showed that altering one amino acid within the murine amelogenin sequence (natural variants T21 and P41T, and experimental variant P71T) resulted in an increase in the quantity of protein adsorbed onto hydroxyapatite (HAP) and the formation of multiple protein layers. Quantitative analysis of the equilibrium adsorbate amounts revealed that the protein variants had higher oligomer-oligomer binding energies. MMP20 enzyme degradation and HAP mineralization studies showed that the amino acid variants slowed the degradation of amelogenin by MMP20 and inhibited the growth and phase transformation of HAP. We propose that the protein variants cause malformed enamel because they bind excessively to HAP and disrupt the normal HAP growth and enzymatic degradation processes. The in situ methods applied to determine the energetics of molecular level processes are powerful tools toward understanding the mechanisms of biomineralization.


Asunto(s)
Amelogénesis Imperfecta/genética , Amelogenina/genética , Biomineralización/genética , Proteínas de la Matriz Extracelular/genética , Adsorción/genética , Amelogénesis Imperfecta/metabolismo , Amelogénesis Imperfecta/patología , Amelogenina/química , Secuencia de Aminoácidos/genética , Sustitución de Aminoácidos/genética , Aminoácidos/química , Aminoácidos/genética , Animales , Durapatita/química , Metabolismo Energético/genética , Proteínas de la Matriz Extracelular/química , Humanos , Metaloproteinasa 20 de la Matriz/química , Metaloproteinasa 20 de la Matriz/genética , Ratones , Microscopía de Fuerza Atómica , Conformación Proteica , Termodinámica
2.
Worldviews Evid Based Nurs ; 19(2): 94-99, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35229980

RESUMEN

BACKGROUND: Pressure injury (PI) is a significant health problem among inpatients that affects their health, quality of life, and expenses. AIM: This systematic review aimed to compare effects of alternating pressure air mattresses (APMs) with other types of supporting surfaces as a tool for PI prevention. METHODS: The literature published between 2009 and 2020 was searched using the databases PubMed, EMBASE, CINAHL, and Cochrane. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses process was followed, including independent study selection and data extraction. Quality appraisal was conducted using the Cochrane Risk of Bias Tool (RoB 2.0). RESULTS: A total of six randomized controlled trials (RCTs) were analyzed. The incidence of hospital-acquired PIs at stage 1 or higher was reported in the APM group from 0.3% to 25%. In one study, APMs were found to be less effective than static air mattresses (SAMs); in contrast, two studies found no difference. In one study, the APM was reported to be more effective than the viscoelastic foam mattress (VFM). On the contrary, in a more recent study, the APM was reported to be less effective than the VFM, and there was no difference compared with high-specification foam mattresses in another study. Using the RoB 2.0 tool, one study was evaluated at "low risk of bias," another as "some concern," and four as "high risk." LINKING EVIDENCE TO ACTION: There is insufficient evidence to suggest that APM is more effective in preventing PIs than other supporting surfaces. Evidence to date suggests that APM can be used in patients at risk for PIs. It is important to change position regardless of the type of support surface used. Highly controlled RCTs with low risk of bias are needed to provide strong evidence for identifying the most effective PI prevention support surfaces.


Asunto(s)
Úlcera por Presión , Aire , Lechos , Humanos , Incidencia , Úlcera por Presión/epidemiología , Úlcera por Presión/prevención & control , Ensayos Clínicos Controlados Aleatorios como Asunto
3.
Bioconjug Chem ; 26(3): 593-601, 2015 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-25730280

RESUMEN

Methods to covalently conjugate Alexa Fluor dyes to cellulose nanocrystals, at limiting amounts that retain the overall structure of the nanocrystals as model cellulose materials, were developed using two approaches. In the first, aldehyde groups are created on the cellulose surfaces by reaction with limiting amounts of sodium periodate, a reaction well-known for oxidizing vicinal diols to create dialdehyde structures. Reductive amination reactions were then applied to bind Alexa Fluor dyes with terminal amino-groups on the linker section. In the absence of the reductive step, dye washes out of the nanocrystal suspension, whereas with the reductive step, a colored product is obtained with the characteristic spectral bands of the conjugated dye. In the second approach, Alexa Fluor dyes were modified to contain chloro-substituted triazine ring at the end of the linker section. These modified dyes then were reacted with cellulose nanocrystals in acetonitrile at elevated temperature, again isolating material with the characteristic spectral bands of the Alexa Fluor dye. Reactions with Alexa Fluor 546 are given as detailed examples, labeling on the order of 1% of the total glucopyranose rings of the cellulose nanocrystals at dye loadings of ca. 5 µg/mg cellulose. Fluorescent cellulose nanocrystals were deposited in pore network microfluidic structures (PDMS) and proof-of-principle bioimaging experiments showed that the spatial localization of the solid cellulose deposits could be determined, and their disappearance under the action of Celluclast enzymes or microbes could be observed over time. In addition, single molecule fluorescence microscopy was demonstrated as a method to follow the disappearance of solid cellulose deposits over time, following the decrease in the number of single blinking dye molecules with time instead of fluorescent intensity.


Asunto(s)
Microambiente Celular , Celulosa/análisis , Colorantes Fluorescentes/química , Nanopartículas/química , Compuestos de Quinolinio/química , Celulosa/química , Microscopía Fluorescente/métodos
4.
Mater Today Adv ; 182023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37324279

RESUMEN

Organic macromolecules exert remarkable control over the nucleation and growth of inorganic crystallites during (bio)mineralization, as exemplified during enamel formation where the protein amelogenin regulates the formation of hydroxyapatite (HAP). However, it is poorly understood how fundamental processes at the organic-inorganic interface, such as protein adsorption and/or incorporation into minerals, regulates nucleation and crystal growth due to technical challenges in observing and characterizing mineral-bound organics at high-resolution. Here, atom probe tomography techniques were developed and applied to characterize amelogenin-mineralized HAP particles in vitro, revealing distinct organic-inorganic interfacial structures and processes at the nanoscale. Specifically, visualization of amelogenin across the mineralized particulate demonstrates protein can become entrapped during HAP crystal aggregation and fusion. Identification of protein signatures and structural interpretations were further supported by standards analyses, i.e., defined HAP surfaces with and without amelogenin adsorbed. These findings represent a significant advance in the characterization of interfacial structures and, more so, interpretation of fundamental organic-inorganic processes and mechanisms influencing crystal growth. Ultimately, this approach can be broadly applied to inform how potentially unique and diverse organic-inorganic interactions at different stages regulates the growth and evolution of various biominerals.

5.
Anal Biochem ; 421(2): 477-81, 2012 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-22019765

RESUMEN

We report here that under different physiological conditions, biomolecular drugs can be stockpiled in a nanoporous support and afterward can be instantly released when needed for acute responses, and the biomolecular drug molecules can also be gradually released from the nanoporous support over a long time for a complete recovery. Organophosphorus acid anhydrolase (OPAA) was spontaneously and largely entrapped in functionalized mesoporous silica (FMS) due to the dominant electrostatic interaction. The OPAA-FMS composite exhibited a burst release in a pH 9.0 NaHCO3-Na2CO3 buffer system and a gradual release in pH 7.4 simulated body fluid. The binding of OPAA to NH2-FMS can result in less tyrosinyl and tryptophanyl exposure OPAA molecules to aqueous environment. The bound OPAA in FMS displayed lower activity than the free OPAA in solution prior to the enzyme entrapment. However, the released enzyme maintained the native conformational structure and the same high enzymatic activity as that prior to the enzyme entrapment. The in vitro results in the rabbit serum demonstrate that both OPAA-FMS and the released OPAA may be used as a medical countermeasure against the organophosphorus nerve agents.


Asunto(s)
Arildialquilfosfatasa/química , Sustancias para la Guerra Química/química , Enzimas Inmovilizadas/química , Sistema Nervioso/efectos de los fármacos , Dióxido de Silicio/química , Animales , Sustancias para la Guerra Química/toxicidad , Microscopía Electrónica de Transmisión , Conejos , Espectrometría de Fluorescencia
6.
Microporous Mesoporous Mater ; 153: 166-170, 2012 May 12.
Artículo en Inglés | MEDLINE | ID: mdl-22287934

RESUMEN

We report here a concept converting carbon dioxide to biocarbonate in a biomimetic nanoconfiguration. Carbonic anhydrase (CA), the fastest enzyme that can covert carbon dioxide to bicarbonate, can be spontaneously entrapped in carboxylic acid group-functionalized mesoporous silica (HOOC-FMS) with super-high loading density (up to 0.5 mg of protein/mg of FMS) in sharp contrast to normal porous silica. The binding of CA to HOOC-FMS resulted in a partial conformational change comparing to the enzyme free in solution, but it can be overcome with increased protein loading density. The higher the protein loading density, the less conformational change, hence the higher enzymatic activity and the higher enzyme immobilization efficiency (up to >60%). The released enzyme still displayed the native conformational structure and the same high enzymatic activity as that prior to the enzyme entrapment, indicating that the conformational change resulted from the electrostatic interaction of CA with HOOC-FMS was not permanent. This work may provide a new approach converting carbon dioxide to biocarbonate that can be integrated with the other part of biosynthesis process for the assimilation of carbon dioxide.

7.
Artículo en Inglés | MEDLINE | ID: mdl-35270615

RESUMEN

This study aimed to understand and describe the experiences of nurses who cared for patients with COVID-19. A descriptive phenomenological approach was used to collect data from individual in-depth interviews with 14 nurses, from 20 October 2020 to 15 January 2021. Data were analyzed using the phenomenological method of Colaizzi. Five theme clusters emerged from the analysis: (1) nurses struggling under the weight of dealing with infectious disease, (2) challenges added to difficult caring, (3) double suffering from patient care, (4) support for caring, and (5) expectations for post-COVID-19 life. The findings of this study are useful primary data for developing appropriate measures for health professionals' wellbeing during outbreaks of infectious diseases. Specifically, as nurses in this study struggled with mental as well as physical difficulties, it is suggested that future studies develop and apply mental health recovery programs for them. To be prepared for future infectious diseases and contribute to patient care, policymakers should improve the work environment, through various means, such as nurses' practice environment management and incentives.


Asunto(s)
COVID-19 , Enfermeras y Enfermeros , Actitud del Personal de Salud , Humanos , Atención al Paciente , SARS-CoV-2
8.
J Phys Chem B ; 126(16): 3135-3142, 2022 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-35420819

RESUMEN

Microsized pore parameters, such as pore size and distance between pores in a series of model EPDM rubbers, were determined in situ under the pressure of 500 psi using 129Xe nuclear magnetic resonance (NMR) techniques: spin-lattice (T1) and spin-spin (T2) relaxation measurements, pulsed-field gradient (PFG) NMR, and two-dimensional exchange spectroscopy (2D EXSY). The T1/T2 (≫1) ratio for the xenon confined in the pores is larger than that for nonconfined free xenon. This suggests that almost the entire pore surface interacts with xenon atoms like a closed pore. While these pores still connect each other through very narrow diffusion/exchange channels, it is possible to observe the echo decay in PFG-NMR and cross-peaks in 2D EXSY. The results show that both diffusion (Dpore ≈ 2.1 × 10-10 m2/s) and exchange (exchange rate, τexch = a few tens of milliseconds) of xenon between a pore within the material and outer surface are prolonged. The exchange distances (l), which correspond to the xenon gas penetration depth, were estimated to be 70-100 µm based on the measured diffusion coefficients and exchange rate (1/τexch). NMR diffraction analysis reveals that pore size (a) and pore distance (b) are on the order of magnitude of micrometers and tens of micrometers, while the diffusion coefficients of xenon gas in the diffusion channels (Deff) are about 10-8 m2/s. Overall, this study suggests that the pores with a few micrometers connected through very narrow flowing channels with the length of several tens of micrometers are developed 70 to 100 µm below the rubber surface. Furthermore, the overall steady-state diffusion of xenon is slower, approximately 2 orders of magnitudes, than the diffusion in the channel between the pores. The pore and exchange distances correlated with the composition of rubbers showed that the properties of EPDM rubber as a high-pressure gas barrier could be improved by reducing the size of cracks and the depth of gas penetration by the addition of both carbon black and silica fillers.

9.
Qual Life Res ; 20(4): 529-35, 2011 May.
Artículo en Inglés | MEDLINE | ID: mdl-21127998

RESUMEN

BACKGROUND: We evaluated the reliability and validity of the Pediatric Functional Assessment of Cancer Therapy-Childhood Brain Tumor Survivor version 2.0 (pedsFACT-BrS; patient version for grade school children aged 7-12 years). METHODS: After translating and cross-culturally adapting it into Korean, the psychometric properties of the pedsFACT-BrS were evaluated in 148 childhood brain tumor survivors (mean age, 9.67 years). Pre-testing was performed in 25 patients. RESULTS: The pedsFACT-BrS showed good symptom coverage and overall user comprehension. Internal consistency was acceptable, with Cronbach's α coefficients ranging from 0.70 to 0.92. The pedsFACT-BrS also demonstrated good convergent and divergent validities when correlated with the Revised Children's Manifest Anxiety Scale and Kovacs' Children's Depression Scale. The pedsFACT-BrS showed good known-group validity and effectively differentiated between clinically distinct patient groups (patient vs. control groups, and among patients having different Karnofsky scores), but offered only partial discrimination of physical well-being (PWB) scores when patients were grouped by treatment type. CONCLUSIONS: Our results indicate that this instrument is reliable and valid and can be used to evaluate the quality of life of Korean childhood brain tumor survivors.


Asunto(s)
Neoplasias Encefálicas/fisiopatología , Calidad de Vida , Encuestas y Cuestionarios/normas , Sobrevivientes , Neoplasias Encefálicas/psicología , Neoplasias Encefálicas/terapia , Niño , Femenino , Humanos , Masculino , Psicometría , República de Corea
10.
Artículo en Inglés | MEDLINE | ID: mdl-34501740

RESUMEN

The aim of this cross-sectional study was to determine the incidence, types, and factors associated with medical adhesive-related skin injuries (MARSIs) among spinal surgery patients. Adult patients who underwent planned spinal surgery under general anesthesia at a tertiary hospital in Seoul, Korea were enrolled. Data were collected from March through April 2019. Skins under surgical wound dressings were evaluated for MARSI once every morning until discharge. Skin injuries lasting for 30 min or more were considered as MARSIs. Logistic regression was performed to identify factors associated with MARSI. The incidence of MARSIs in surgical areas was 36.4% and the rate per 100 medical adhesives was 9.8%. All MARSIs occurred on postoperative day 1 or 2. A history of contact dermatitis (OR = 10.517, 95% CI = 3.540-31.241, p < 0.001) and late ambulation (OR = 1.053, 95% CI = 1.012-1.095, p = 0.010) were identified as risk factors for MARSI. Spinal surgery patients were at high risk of MARSIs associated with surgical wound dressings. Patients with a history of contact dermatitis or prolonged bed rest periods need more active skin assessment and more careful skin care to prevent MARSIs after spinal surgery.


Asunto(s)
Enfermedades de la Piel , Herida Quirúrgica , Adhesivos/efectos adversos , Adulto , Vendajes , Estudios Transversales , Humanos , Piel , Herida Quirúrgica/epidemiología
11.
Artículo en Inglés | MEDLINE | ID: mdl-34639293

RESUMEN

Insufficient research exists for position change intervals to eradicate pressure ulcers. We tried to provide evidence for the position change interval by comparing peak pressure, risk area ratio, and the time to reach 30 mmHg and 60 mmHg, and presented this in detail, according to the angle in the three positions. The study conducted RCTs on a total of 64 healthy adults. For two hours, interface pressure measurements were compared with 30° and 90° tilting at the inclined, 0° and 45° head-of-bed (HOB) elevation at the supine, and 30° and 45° HOB elevation at the Fowler's position. The peak pressure on 30° tilting remained less than 60 mmHg for 2 h, unlike 90° tilting. To reach 60 mmHg took 78.18 min at 30° tilting, within 30 min at the 30° supine, 30° and 45° at the Fowler's position, and 39.55 min at 0° supine. The pressure difference according to the angles was only significant at 30° and 90° tilting, with no difference in the other groups. To prevent pressure ulcers, position changes are required every 2 h in the 30° tilting position, every 1.5 to 2 h at 0° supine, and at least every 1.5 h for all the other positions.


Asunto(s)
Úlcera por Presión , Adulto , Humanos , Presión , Úlcera por Presión/prevención & control , Posición Supina
12.
Membranes (Basel) ; 11(5)2021 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-33925914

RESUMEN

Graphene oxide (GO) is a promising membrane system for chemical separation applications due to its 2-D nanofluidics properties and an ability to control interplanar spacing for selectivity. The permeance of water, methanol (MeOH) and isopropyl alcohol (IPA) through 5 µm thick membranes was found to be 0.38 ± 0.15, 0.33 ± 0.16 and 0.42 ± 0.31 LMH/bar (liter/m2·h·bar), respectively. Interestingly, the permeance of a water-alcohol mixture was found to be dramatically lower (~0.01 LMH/bar) than any of its components. Upon removing the solvent mixture, the transmembrane flux of the pure solvent was recovered to near the original permeance. The interlayer space of a dried GO membrane was found to be 8.52 Å, which increased to 12.19 Å. 13.26 Å and 16.20 Å upon addition of water, MeOH and IPA. A decrease in d-space, about 2 Å, was consistently observed when adding alcohol to water wetted GO membrane and an optical color change and reduction in permeance. A newly proposed mechanism of a partial reduction of GO through a catalytic reaction with the water-alcohol mixture is consistent with experimental observations.

13.
RSC Adv ; 11(26): 15512-15518, 2021 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-35481209

RESUMEN

Since the 1950's the Earth's natural carbon cycle has not sufficiently sequestrated excess atmospheric CO2 contributed by human activities. CO2 levels rose above 400 ppm in 2013 and are forecasted to exceed 500 ppm by 2070, a level last experienced during the Paleogene period 25-65 MYA. While humanity benefits from the extraction and combustion of carbon from Earth's crust, we have overlooked the impact on global climate change. Here, we present a strategy to mine atmospheric carbon to mitigate CO2 emissions and create economically lucrative green products. We employ an artificial carbon cycle where agricultural plants capture CO2 and the carbon is transformed into silicon carbide (SiC), a valuable commercial material. By carefully quantifying the process we show that 14% of plant-sequestered carbon is stored as SiC and estimate the scale needed for this process to have a global impact.

14.
J Am Chem Soc ; 132(20): 6906-7, 2010 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-20433206

RESUMEN

We report that antibodies can be spontaneously loaded in functionalized mesoporous silica (FMS) with superhigh density (0.4-0.8 mg of antibody/mg of FMS) due to their comprehensive noncovalent interaction. The superhigh loading density and noncovalent interaction between FMS and antibodies allow long-lasting local release of the immunoregulatory molecules from FMS under physiological conditions. Preliminary data indicate that FMS-anti-CTLA4 antibody injected directly into a mouse melanoma induces much greater and extended inhibition of tumor growth than the antibody given systemically. Our findings open up a novel approach for local delivery of therapeutically active proteins to tumors and, potentially, other diseases.


Asunto(s)
Anticuerpos Inmovilizados/administración & dosificación , Anticuerpos Inmovilizados/uso terapéutico , Inmunoterapia , Nanoestructuras/química , Neoplasias/terapia , Animales , Anticuerpos Inmovilizados/química , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/uso terapéutico , Humanos , Inmunoglobulina G/química , Inmunoglobulina G/uso terapéutico , Ratones , Porosidad , Ratas , Dióxido de Silicio/química
15.
Anal Chem ; 82(7): 2989-95, 2010 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-20201502

RESUMEN

A novel electrochemical immunosensor for sensitive detection of cancer biomarker alpha-fetoprotein (AFP) is described that uses a graphene sheet sensor platform and functionalized carbon nanospheres (CNSs) labeled with horseradish peroxidase-secondary antibodies (HRP-Ab2). Greatly enhanced sensitivity for the cancer biomarker is based on a dual signal amplification strategy: first, the synthesized CNSs yielded a homogeneous and narrow size distribution, which allowed several binding events of HRP-Ab2 on each nanosphere. Enhanced sensitivity was achieved by introducing the multibioconjugates of HRP-Ab2-CNSs onto the electrode surface through "sandwich" immunoreactions. Second, functionalized graphene sheets used for the biosensor platform increased the surface area to capture a large amount of primary antibodies (Ab1), thus amplifying the detection response. On the basis of the dual signal amplification strategy of graphene sheets and the multienzyme labeling, the developed immunosensor showed a 7-fold increase in detection signal compared to the immunosensor without graphene modification and CNSs labeling. The proposed method could respond to 0.02 ng mL(-1) AFP with a linear calibration range from 0.05 to 6 ng mL(-1). This amplification strategy is a promising platform for clinical screening of cancer biomarkers and point-of-care diagnostics.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Técnicas Biosensibles/métodos , Carbono/química , Inmunoensayo/métodos , Nanosferas/química , Anticuerpos Inmovilizados/química , Anticuerpos Inmovilizados/metabolismo , Técnicas Electroquímicas , Enzimas Inmovilizadas/metabolismo , Peroxidasa de Rábano Silvestre/química , Peroxidasa de Rábano Silvestre/metabolismo , alfa-Fetoproteínas/metabolismo
16.
Environ Sci Technol ; 44(16): 6390-5, 2010 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-20608701

RESUMEN

Copper has been identified as a pollutant of concern by the U.S. Environmental Protection Agency (EPA) because of its widespread occurrence and toxic impact in the environment. Three nanoporous sorbents containing chelating diamine functionalities were evaluated for Cu(2+) adsorption from natural waters: ethylenediamine functionalized self-assembled monolayers on mesoporous supports (EDA-SAMMS), ethylenediamine functionalized activated carbon (AC-CH(2)-EDA), and 1,10-phenanthroline functionalized mesoporous carbon (Phen-FMC). The pH dependence of Cu(2+) sorption, Cu(2+) sorption capacities, rates, and selectivity of the sorbents were determined and compared with those of commercial sorbents (Chelex-100 ion-exchange resin and Darco KB-B activated carbon). All three chelating diamine sorbents showed excellent Cu(2+) removal (approximately 95-99%) from river water and seawater over the pH range 6.0-8.0. EDA-SAMMS and AC-CH(2)-EDA demonstrated rapid Cu(2+) sorption kinetics (minutes) and good sorption capacities (26 and 17 mg Cu/g sorbent, respectively) in seawater, whereas Phen-FMC had excellent selectivity for Cu(2+) over other metal ions (e.g., Ca(2+), Fe(2+), Ni(2+), and Zn(2+)) and was able to achieve Cu below the EPA recommended levels for river and sea waters.


Asunto(s)
Quelantes/química , Cobre/aislamiento & purificación , Diaminas/química , Nanoestructuras/química , Ríos/química , Agua de Mar/química , Contaminantes Químicos del Agua/aislamiento & purificación , Adsorción , Cationes Bivalentes/química , Concentración de Iones de Hidrógeno , Cinética , Porosidad , Soluciones , Temperatura
17.
ACS Omega ; 5(23): 13894-13901, 2020 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-32566856

RESUMEN

Wood and plant fibers have been studied as natural sorbent materials for treating aquatic oil spills; however, the effectiveness of these materials is limited by their tendency to absorb water as well as oil. Chemical pretreatment of cotton fibers with fatty acids was examined as a means of enhancing the performance of cotton as a sorbent for crude oil. A raw cotton fiber was chemically modified with C18 fatty acid by simple leaving group chemistry. Free surface hydroxyl groups were modified with long alkyl chains to create fibers that displayed increased water contact angles, indicative of a significant decrease in surface energy. The increased affinity for oil and corresponding repulsion of water on the individual modified fibers translated to greater sorption of oil and rejection of water by loose assemblies of fibers (i.e., balls or yarn) when compared with unmodified cotton. X-ray diffraction (XRD) pattern, Fourier transform infrared (FT-IR), 13C cross-polarization/magic angle spinning solid-state nuclear magnetic resonance (CP/MAS SSNMR), and scanning electron microscopy (SEM) showed that cotton fibers were significantly exfoliated by the intercalation of C18 fatty acids about 2.4 times in its diameter. In the presence of seawater, the highly oleophilic C18 fatty acid-modified cotton fiber showed a maximum oil sorption capacity of 35.58 g per gram of fiber, about ∼49% greater than that of the corresponding raw cotton fiber.

18.
Midwifery ; 89: 102788, 2020 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-32615484

RESUMEN

BACKGROUND: Most women experience perineal pain after childbirth. Sustained perineal pain affects mother's daily living. Various methods have been used to relieve postpartum perineal pain, such as cold or warm therapy, but the pain-control effects of cryotherapy are still controversial. AIMS: The purpose of this study was to verify the effectiveness of cryotherapy in relieving perineal pain in women after childbirth. METHODS: The researchers searched the CINAHL, Cochrane, EMBASE, PubMed, Korea Education and Research Information Service, NDSL, KoreaMed, LILACS and SciELO databases for studies to include in this review, and selected studies using PICO criteria. Methodological quality was assessed based on Cochrane's risk of bias 2 for randomized controlled trials. Data were analyzed with the Comprehensive Meta-Analysis program. FINDINGS: Eleven published studies encompassing 1,492 participants were included. Cryotherapy significantly reduced pain two days postpartum. Ice packs and gel packs had similar pain-relieving effects. Cryotherapy did not differ significantly from Epifoam therapy (hydrocortisone-pramoxine) in its effects on perineal pain one day or five days after childbirth. CONCLUSIONS: Cryotherapy can be an effective non-pharmacological nursing intervention to reduce pain after childbirth.


Asunto(s)
Crioterapia/normas , Dolor/etiología , Parto/psicología , Perineo/lesiones , Adulto , Crioterapia/métodos , Episiotomía/efectos adversos , Episiotomía/psicología , Femenino , Humanos , Dolor/psicología , Manejo del Dolor/métodos , Perineo/fisiopatología , Embarazo
19.
Biochem Biophys Res Commun ; 390(4): 1177-81, 2009 Dec 25.
Artículo en Inglés | MEDLINE | ID: mdl-19874798

RESUMEN

We have previously reported that organophosphorus hydrolase (OPH) can be spontaneously entrapped in functionalized mesoporous silica (FMS) with HOOC- as the functional groups and the entrapped OPH in HOOC-FMS showed enhanced enzyme specific activity. This work is to study the mechanisms that why OPH entrapped in FMS displayed the enhanced activity in views of OPH-FMS interactions using spectroscopic methods. The circular dichroism (CD) spectra show that, comparing to the secondary structure of OPH free in solution, OPH in HOOC-FMS displayed increased alpha-helix/beta-strand transition of OPH with increased OPH loading density. The fluorescence emission spectra of Trp residues were used to assess the tertiary structural changes of the enzyme. There was a 42% increase in fluorescence. This is in agreement with the fact that the fluorescence intensity of OPH was increased accompanying with the increased OPH activity when decreasing urea concentrations in solution. The steady-state anisotropy was increased after OPH entrapping in HOOC-FMS comparing to the free OPH in solution, indicating that protein mobility was reduced upon entrapment. The solvent accessibility of Trp residues of OPH was probed by using acrylamide as a collisional quencher. Trp residues of OPH-FMS had less solvent exposure comparing with free OPH in solution due to its electrostatical binding to HOOC-FMS thereby displaying the increased fluorescence intensity. These results suggest the interactions of OPH with HOOC-FMS resulted in the protein immobilization and a favorable conformational change for OPH in the crowded confinement space and accordingly the enhanced activity.


Asunto(s)
Arildialquilfosfatasa/química , Enzimas Inmovilizadas/química , Dióxido de Silicio/química , Catálisis , Dicroismo Circular , Porosidad , Estructura Secundaria de Proteína , Espectrometría de Fluorescencia
20.
Inorg Chem Commun ; 12(11): 1099-1103, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23762013

RESUMEN

Functional mesoporous carbon has been built using 1,10-phenanthroline as the fundamental building block, resulting in a nanoporous, high surface area sorbent capable of selectively binding transition metal ions. This material had a specific surface area of 870 m2/g, an average pore size of about 30 Å, and contained as much as 8.2 wt% N. Under acidic conditions, where the 1,10-phenanthroline ligand is protonated, this material was found to be an effective anion exchange material for transition metal anions like [Formula: see text] and [Formula: see text]. 1,10-Phenanthroline functionalized mesoporous carbon ("Phen-FMC") was found to have a high affinity for Cu(II), even down to a pH of 1. At pHs above 5, Phen-FMC was found to bind a variety of transition metal cations (e.g. Co(II), Ni(II), Zn(II), etc.) from filtered ground water, river water and seawater. Phen-FMC displayed rapid sorption kinetics with Co(II) in filtered river water, reaching equilibrium in less than an hour, and easily lowering the [Co(II)] to sub-ppb levels. Phen-FMC was found to be more effective for transition metal ion capture than ion-exchange resin or activated carbon.

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