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1.
IEEE J Transl Eng Health Med ; 12: 468-479, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38899145

RESUMO

OBJECTIVE: Blood circulation is an important indicator of wound healing. In this study, a tissue oxygen saturation detecting (TOSD) system that is based on multispectral imaging (MSI) is proposed to quantify the degree of tissue oxygen saturation (StO2) in cutaneous tissues. METHODS: A wound segmentation algorithm is used to segment automatically wound and skin areas, eliminating the need for manual labeling and applying adaptive tissue optics. Animal experiments were conducted on six mice in which they were observed seven times, once every two days. The TOSD system illuminated cutaneous tissues with two wavelengths of light - red ([Formula: see text] nm) and near-infrared ([Formula: see text] nm), and StO2 levels were calculated using images that were captured using a monochrome camera. The wound segmentation algorithm using ResNet34-based U-Net was integrated with computer vision techniques to improve its performance. RESULTS: Animal experiments revealed that the wound segmentation algorithm achieved a Dice score of 93.49%. The StO2 levels that were determined using the TOSD system varied significantly among the phases of wound healing. Changes in StO2 levels were detected before laser speckle contrast imaging (LSCI) detected changes in blood flux. Moreover, statistical features that were extracted from the TOSD system and LSCI were utilized in principal component analysis (PCA) to visualize different wound healing phases. The average silhouette coefficients of the TOSD system with segmentation (ResNet34-based U-Net) and LSCI were 0.2890 and 0.0194, respectively. CONCLUSION: By detecting the StO2 levels of cutaneous tissues using the TOSD system with segmentation, the phases of wound healing were accurately distinguished. This method can support medical personnel in conducting precise wound assessments. Clinical and Translational Impact Statement-This study supports efforts in monitoring StO2 levels, wound segmentation, and wound healing phase classification to improve the efficiency and accuracy of preclinical research in the field.


Assuntos
Algoritmos , Saturação de Oxigênio , Pele , Cicatrização , Cicatrização/fisiologia , Animais , Camundongos , Pele/metabolismo , Pele/diagnóstico por imagem , Pele/irrigação sanguínea , Oxigênio/metabolismo , Processamento de Imagem Assistida por Computador/métodos , Masculino , Imageamento Hiperespectral/métodos
2.
Hu Li Za Zhi ; 71(2): 104-111, 2024 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-38532680

RESUMO

The post-operative intensive care experience of a school-aged child who received living-donor bilateral lobar lung transplantation due to acute respiratory distress syndrome and interstitial pulmonary fibrosis is discussed in this paper. The patient received lungs donated by her parents in a "living-donor bilateral lobar lung transplantation" due to severe lung function impairment. The patient felt anxious due to her long-term hospitalization for preoperative evaluation, various invasive treatments, and postoperative rehabilitation. During the care period from October 25th, 2022, to December 29th, 2022, the author collected data via direct care, interviews, medical record reviews, and interactions with the patient and her family. An assessment of the patient's physical, mental, and social integrity was made, and the collected data were organized and analyzed to identify health issues such as lack of activity endurance, imbalanced nutrition below bodily requirements, and anxiety. After the lung transplantation operation, the interdisciplinary team worked collaboratively to develop a care plan to improve cardiopulmonary endurance and enhance the quality of care for the patient through early care and rehabilitation via proactive care. This care plan included encouraging the patient and her parents to express their fears and feelings and using flashcards to teach them about dietary management and the proper performance of lung rehabilitation. These measures encouraged the parents to engage in care, properly prepare for discharge care, and receive care education. As this is the first case of living-donor lobar lung transplantation in Taiwan, this valuable nursing experience is expected to provide future care teams with a reference on the related nursing process and care experience for similar cases.


Assuntos
Doadores Vivos , Transplante de Pulmão , Criança , Feminino , Humanos , Taiwan
3.
Child Care Health Dev ; 50(2): e13238, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38380721

RESUMO

PURPOSE: Managing type 1 diabetes (T1D) challenges children and their parents. Parents need to learn the necessary skills and later transfer the responsibility of care to their children as they develop. The transition process involves autonomy in behaviour and decision-making. This study explores the shared management experiences of Taiwanese parents and their children with type 1 diabetes. DESIGN AND METHODS: This study employed a qualitative design using a grounded theory approach. Purposive sampling was used at a medical centre in Taiwan for participant recruitment. Twenty-nine parents of children who had been diagnosed with T1D were interviewed in-depth. Data were analysed using constant comparison and repeated verification. RESULTS: After a child was diagnosed with T1D, the parents initiated 'Life-long lesson: Growing together with the child on the road to normality'. Three main categories emerged: 'confronting the disease diagnosis', 'establishing supportive and collaborative involvement' and 'assisting the child in building a sense of belonging'. Sub-categories within each significant category were also included. CONCLUSIONS: Taiwanese parents perhaps have a controlling or directive role for a long period in their child's lives and shared management of their health condition. This study's findings can help healthcare workers better understand the process of parents' shared management of T1D with their children and how to best communicate with children about the disease and care in accordance with the child's stage of development.


Assuntos
Diabetes Mellitus Tipo 1 , Criança , Humanos , Diabetes Mellitus Tipo 1/terapia , Pais , Pessoal de Saúde , Projetos de Pesquisa , Teoria Fundamentada , Pesquisa Qualitativa
4.
Child Abuse Negl ; 147: 106600, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38118290

RESUMO

BACKGROUND: Among nearly 400,000 children in US foster care, an estimated 10 % are medically complex. Yet, population-level data about children with medical complexity (CMC) served by the child welfare system, both for prevention and foster care services, are largely unavailable. OBJECTIVE: To understand how US child welfare agencies define, identify, and track CMC. PARTICIPANTS AND SETTING: Child welfare agencies across the US. METHODS: Agencies were recruited to complete a survey as part of a larger study exploring how CMC are served by the child welfare system. Survey responses related to defining, identifying, and tracking CMC were included in analysis. Descriptive statistical analysis was conducted with Stata. Qualitative content and thematic analysis were applied to free text responses. RESULTS: Surveys were completed by agencies from 28 states and 2 major cities. Nearly half of the agencies did not have a clear definition to identify CMC; those that did have a definition often lacked standardization. The majority of agencies could not easily identify CMC or access CMC-related data within data systems. Agencies described lack of a clear definition as a barrier to collecting population level data. CONCLUSIONS: Many US child welfare agencies lack a clear definition to identify and track CMC, impacting the ability to tailor care and service delivery to meet their unique needs. To address this, a clear definition for CMC should be developed and consistently applied within child welfare data systems. Once CMC are identifiable, future research can collect population-level data and provide recommendations for best practices and policies.


Assuntos
Proteção da Criança , Cuidados no Lar de Adoção , Criança , Humanos , Serviços de Proteção Infantil , Projetos de Pesquisa
5.
Mater Today Bio ; 19: 100576, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36816601

RESUMO

The tumor microenvironment (TME) is known to direct cancer cell growth, migration, invasion into the matrix and distant tissues, and to confer drug resistance in cancer cells. While multiple aspects of TME have been studied using in vitro, ex vivo, and in vivo tumor models and engineering tools, the influence of matrix viscoelasticity on pancreatic cancer cells and its associated TME remained largely unexplored. In this contribution, we synthesized a new biomimetic hydrogel with tunable matrix stiffness and stress-relaxation for evaluating the effect of matrix viscoelasticity on pancreatic cancer cell (PCC) behaviors in vitro. Using three simple monomers and Reverse-Addition Fragmentation Chain-Transfer (RAFT) polymerization, we synthesized a new class of phenylboronic acid containing polymers (e.g., poly (OEGA-s-HEAA-s-APBA) or PEHA). Norbornene group was conjugated to HEAA on PEHA via carbic anhydride, affording a new NB and BA dually modified polymer - PEHNBA amenable for orthogonal thiol-norbornene photopolymerization and boronate ester diol complexation. The former provided tunable matrix elasticity, while the latter gave rise to matrix stress-relaxation (or viscoelasticity). The new PEHNBA polymers were shown to be highly cytocompatible for in situ encapsulation of PCCs and cancer-associated fibroblasts (CAFs). Furthermore, we demonstrated that hydrogels with high stress-relaxation promoted spreading of CAFs, which in turns promoted PCC proliferation and spreading in the viscoelastic matrix. Compared with elastic matrix, viscoelastic gels upregulated the secretion of soluble proteins known to promote epithelial-mesenchymal transition (EMT). This study demonstrated the crucial influence of matrix viscoelasticity on pancreatic cancer cell fate and provided an engineered viscoelastic matrix for future studies and applications related to TME.

6.
Biomater Adv ; 134: 112712, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35581097

RESUMO

Mesenchymal stem cells (MSCs)-based therapies have been widely used to promote tissue regeneration and to modulate immune/inflammatory response. The therapeutic potential of MSCs can be further improved by forming multi-cellular spheroids. Meanwhile, hydrogels with macroporous structures are advantageous for improving mass transport properties for the cell-laden matrices. Herein, we report the fabrication of MSC-laden macroporous hydrogel scaffolds through incorporating rapidly dissolvable spherical cell-laden microgels. Dissolvable microgels were fabricated by tandem droplet-microfluidics and thiol-norbornene photopolymerization using a novel fast-degrading macromer poly(ethylene glycol)-norbornene-dopamine (PEGNB-Dopa). The cell-laden PEGNB-Dopa microgels were subsequently encapsulated within another bulk hydrogel matrix, whose porous structure was generated efficiently by the rapid degradation of the PEGNB-Dopa microgels. The cytocompatibility of this in situ pore-forming approach was demonstrated with multiple cell types. Furthermore, adjusting the stiffness and cell adhesiveness of the bulk hydrogels afforded the formation of solid cell spheroids or hollow spheres. The assembly of solid or hollow MSC spheroids led to differential activation of AKT pathway. Finally, MSCs solid spheroids formed in situ within the macroporous hydrogels exhibited robust secretion of HGF, VEGF-A, IL-6, IL-8, and TIMP-2. In summary, this platform provides an innovative method for forming cell-laden macroporous hydrogels for a variety of future biomedical applications.


Assuntos
Hidrogéis , Microgéis , Sobrevivência Celular , Di-Hidroxifenilalanina , Hidrogéis/química , Norbornanos/química , Engenharia Tecidual/métodos
7.
Adv Healthc Mater ; 11(7): e2101284, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34608768

RESUMO

A new class of temperature responsive polymer, termed PADO, is synthesized by reversible addition-fragmentation chain-transfer polymerization. Synthesized from copolymerization of diacetone acrylamide (DAAM), di(ethylene glycol) ethyl ether acrylate, and oligo(ethylene glycol) methyl ether acrylate, PADO polymer phase separates at temperature above its lower critical solution temperature (36-42 °C) due to enhanced hydrophobic interactions between the short ethylene glycol side chains. Solution of PADO polymers exhibit injectable shear-thinning properties and reach sol-gel transition rapidly (<5 min) at 37 °C. When the ketone moieties on DAAM are linked by adipic acid dihydrazdie, PADO polymers form crosslinked and injectable acylhydrazone hydrogels, which are hydrolytically degradable at a mild acidic environment owing to the pH sensitive acylhydrazone bonds. The pH-responsive degradation kinetics can be controlled by tuning polymer contents and ketone/hydrazide ratio. Importantly, the injectable PADO hydrogels are highly cytocompatible and can be easily formulated for pH-responsive sustained protein delivery.


Assuntos
Hidrogéis , Polímeros , Encapsulamento de Células , Etilenoglicóis , Hidrogéis/química , Cetonas , Proteínas , Temperatura
8.
ACS Macro Lett ; 10(3): 341-345, 2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-35549061

RESUMO

An alternate synthesis route was developed to prepare norbornene-functionalized poly(ethylene glycol) (PEG) from reacting multiarm PEG with carbic anhydride. The macromer, PEGNBCA, permits photo-cross-linking of thiol-norbornene hydrogels with kinetics comparable to conventional PEGNB macromer. In addition, PEGNBCA provides an additional carboxylate group for further conjugation with amine-bearing molecules. Interestingly, PEGNBCA thiol-norbornene hydrogels are highly susceptible to hydrolytic degradation through enhanced ester hydrolysis. The ester linkage is further weakened after the secondary conjugation, resulting in extremely rapid degradation of PEGNB hydrogels. More importantly, the degradation can be readily adjusted via tuning macromer compositions, with complete degradation time ranging from hours to weeks. The PEGNBCA hydrogels are also highly cytocompatible toward various cell types, providing opportunities for future applications in tissue engineering and advanced biofabrication.


Assuntos
Norbornanos , Compostos de Sulfidrila , Materiais Biocompatíveis , Ésteres , Hidrogéis
9.
ACS Omega ; 5(7): 3709-3716, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32118186

RESUMO

Vanillic acid, an oxidized form of vanilla, is a flavoring agent with a creamy odor. Several studies have reported the neuroprotective effects of vanillic acid, which are predominantly associated with anti-inflammatory and antioxidative properties. The anti-inflammatory and antioxidative properties may result from Akt or ERK signaling activation. The activation of the mammalian target of rapamycin (mTOR), a key downstream target of Akt and ERK signaling, is a crucial therapeutic target for treating depression. However, the antidepressant effects of vanillic acid remain unknown. The present study applied the forced swim test (FST) to investigate the antidepressant effects of vanillic acid and its association with Akt, ERK, and mTOR signaling and upstream α-amino-3-hydroxy-5-methyl-4-isoxazolepropionaic acid receptor (AMPAR) in the prefrontal cortex (PFC) of mice. Vanillic acid demonstrated antidepressant effects by significantly reducing behavioral despair in the FST. None of the treatments changed locomotor activity. Additionally, vanillic acid increased AMPAR throughput, Akt, and mTOR signaling but not ERK signaling in the PFC. NBQX (an AMPAR blocker), MK 2206 (an Akt blocker), and rapamycin (an mTOR blocker) used in pretreatment attenuated the antidepressant effects of vanillic acid, but SL327 (an ERK inhibitor) did not. The immunochemical results indicated that the antidepressant effects of vanillic acid depend on the AMPAR-Akt-mTOR signaling transduction pathway. Our findings reveal an Akt-dependent, but ERK-independent, the mechanism underlying the antidepressant effects of vanillic acid, which may be beneficial for some patients with depression.

10.
ACS Macro Lett ; 9(6): 781-787, 2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35648526

RESUMO

Here we report microphase-separated poly(styrene-block-dimethylsiloxane) (PS-b-PDMS) as a reinforcing filler in PDMS thermosets that overcomes the long-standing problem of aging in the processing of silica-reinforced silicone. Surprisingly, PS-b-PDMS reinforced composites display comparable mechanical performance to silica-modified analogs, even though the modulus of PS is much smaller than that of silica and there is no evidence of percolation with respect to the rigid PS domains. We have found that a few unique characteristics contribute to the reinforcing performance of PS-b-PDMS. The strong self-assembly behavior promotes batch-to-batch repeatability by having well-dispersed fillers. The structure and size of the fillers depend on the loading and characteristics of both filler and matrix, along with the shear effect. The reinforcing effect of PS-b-PDMS is mostly brought by the entanglements between the corona layer of the filler and the matrix, rather than the hydrodynamic reinforcement of the PS phase.

11.
Nano Lett ; 19(8): 5102-5108, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31271283

RESUMO

The design of efficient catalysts capable of delivering high currents at low overpotentials for hydrogen evolution reactions (HERs) is urgently needed to use catalysts in practical applications. Herein, we report platinum (Pt) alloyed with titanium (Ti) from the surface of Ti3C2Tx MXenes to form Pt3Ti intermetallic compound (IMC) nanoparticles (NPs) via in situ coreduction. In situ X-ray absorption spectroscopy (XAS) indicates that Pt undergoes a temperature-dependent transformation from single atoms to intermetallic compounds, and the catalyst reduced at 550 °C exhibits a superior HER performance in acidic media. The Pt/Ti3C2Tx-550 catalyst outperforms commercial Pt/Vulcan and has a small overpotential of 32.7 mV at 10 mA cm-2 and a low Tafel slope of 32.3 mV dec-1. The HER current was normalized by the mass and dispersion of Pt, and the mass activity and specific activity of Pt/Ti3C2Tx-550 are 4.4 and 13 times higher, respectively, than those of Pt/Vulcan at an overpotential of 70 mV. The density functional theory (DFT) calculations suggest that the (111)- and (100)-terminated Pt3Ti nanoparticles exhibit *H binding comparable to Pt(111), while the (110) termination has an *H adsorption that is too exergonic, thus poisoned in the low overpotential region. This work demonstrates the potential of MXenes as platforms for the design of electrocatalysts and may spur future research for other MXene-supported metal catalysts that can be used for a wide range of electrocatalytic reactions.

12.
ACS Appl Mater Interfaces ; 11(27): 24552-24559, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31246398

RESUMO

A waterborne, UV-blocking, and visually transparent nanocomposite coating was formulated with ZnO nanoparticles and 2-hydroxyethyl cellulose (HEC). The coating is highly effective (<5% UV and ∼65% visible transmittance), and the film thickness (0.2-2.5 µm) is ∼100 times thinner than the conventional coatings of similar UV-blocking performance. The superior properties are due to the fractal structures of ZnO nanoparticles assembled within the HEC matrix, revealed by scanning electron microscopy and small-angle X-ray scattering (SAXS). Changing the binder to 2-hydroxyethyl starch (HES) diminishes the UV-blocking performance, as ZnO nanoparticles form dense globular aggregates, with an aggregation number measured by SAXS 3 orders of magnitude larger than the HEC coating. Since HEC and HES share the same repeating glucose unit in the polymer backbone, it suggests that the conformational characteristics of the binder polymer have a strong influence on the nanoparticle aggregation, which plays a key role in determining the optical performance. Similar structures were achieved with TiO2 nanoparticles. This study not only offers a cost-effective and readily scalable method to fabricate transparent UV-blocking coating but also demonstrates that the unique fractal aggregation structures in a nanocomposite material can provide high performance and functionality without fully dispersing the nanoparticles.

13.
Phys Med ; 63: 1-6, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31221400

RESUMO

PURPOSE: Polymer gel dosimeters provide three-dimensional absorbed dose information and have gradually become a popular tool for quality assurance in radiotherapy. This study aims to incorporate iodine into the MAGAT-based gel as radiation sensitizer and investigate whether it can be used to measure the radiation dose and slice thickness for CT scans. METHODS: The nMAGAT(I) gel was doped with 0.03, 0.05, and 0.07-M iodine. The absorbed dose was delivered using a CT scanner (Alexion 16, Toshiba Medical Systems, Japan) with tube voltages of 80, 100, 120, and 135 kVp. The irradiated nMAGAT(I) gel was read using a cone beam optical CT scanner to produce dose-response curves. The nMAGAT(I) gel was used to obtain the slice sensitivity profile (SSP) and the CT dose index (CTDI) for quality assurance of CT scans. RESULTS: The 0.07-M iodine-doped nMAGAT(I) gel exhibited maximum sensitivity with the dose enhancement ratio of 2.12. The gel was chemically stable 24 h after its preparation, and the polymerization process was completed 24-48 h after the irradiation. For CT quality assurance, the full width at half maximum measured by the nMAGAT(I) gel matched the nominal slice thickness of CT. The CTDI at center, CTDI at peripheral, and weighted CTDI obtained by the nMAGAT(I) gel differed from those obtained by the ionization chamber by -4.2%, 3.1%, and 0.7%, respectively. CONCLUSIONS: The nMAGAT(I) gel can be used to assess radiation doses and slice thickness in CT scans, thus rendering it a potential quality assurance tool for CT and other radiological diagnostic applications.


Assuntos
Iodo/química , Polimetil Metacrilato/química , Dosímetros de Radiação , Tomografia Computadorizada por Raios X/instrumentação , Géis , Imagens de Fantasmas
14.
AJR Am J Roentgenol ; 213(1): 140-146, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30933646

RESUMO

OBJECTIVE. PET/CT provides a fusion of both anatomic and functional information. However, because of the temporal difference of both modalities and respiratory motion of lungs, misregistration of lesions is frequently observed on thoracic PET/CT scans. The effect of cine-averaged CT (CACT) acquisition incorporated with the shallow breathing pattern of patients on the improvement of registration and quantification of lesions was investigated. MATERIALS AND METHODS. Thirty patients with cancer who underwent routine PET/CT followed by CACT of the thoracic region were enrolled. The misalignment between PET/helical CT (HCT) and PET/CACT was calculated. In addition, the PET data were attenuation-corrected by HCT and CACT images, and the maximum standardized uptake value (SUVmax) was evaluated. RESULTS. All lesions in the PET/HCT images showed misalignment larger than 5 mm, whereas only 33% of lesions in the PET/CACT images showed misalignment larger than 5 mm. The mean values of the maximum misalignment of the lesions in PET/HCT and PET/CACT images were 14.10 ± 6.26 mm and 5.92 ± 4.31 mm, respectively. Seven percent of the lesions had an increase in SUVmax of more than 20%, and 47% showed a slight increase in SUVmax of less than 5% after applying CACT. The mean percentage difference between the SUVmax of CACT and that of HCT was 12%. CONCLUSION. Using the CACT technique and the shallow breathing pattern effectively reduces misregistration of lesions and recovers the underestimated SUVmax. The CACT method can be applied in clinical practice of thoracic PET/CT for better cancer management.

15.
Int J Cardiol ; 266: 50-55, 2018 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-29887472

RESUMO

BACKGROUND: The role of false lumen patency related to aortic growth, re-interventions, and post-discharge mortality in the chronic phase of repaired type A acute aortic dissection (TAAAD) remains controversial. We investigated the role of postoperative false lumen patency during long-term follow-up. METHODS: Based on postoperative CT images of 70 candidates, 58 eligible patients without alteration of false lumen status were assigned into three groups: complete patency, partial patency, and complete thrombosis. Aortic growth of 7 levels was analyzed. RESULTS: Persistent complete patency in post-operative TAAAD presents faster expansion of aortic diameter (95% CI, 0.35 to 11.52; P=0.038; B=5.935) and more patients with growth rate>5mm/year (P=0.029). The persistent status of false lumen does not predict post-discharge mortality (P=0.479). History of coronary artery disease (CAD) is the only independent predictor of post-discharge mortality. CONCLUSIONS: In TAAAD patients without change of postoperative false lumen status, completely patent false lumen presents faster aortic growth and more patients with growth rate>5mm/year. False lumen status does not correlate with late survival. Here we provide an insight into persistent postoperative false lumen in TAAAD patients and may help cast light on aortic dissection in this specific subgroup to improve their late outcomes.


Assuntos
Aneurisma da Aorta Torácica/diagnóstico por imagem , Aneurisma da Aorta Torácica/cirurgia , Dissecção Aórtica/diagnóstico por imagem , Dissecção Aórtica/cirurgia , Grau de Desobstrução Vascular/fisiologia , Idoso , Dissecção Aórtica/mortalidade , Aneurisma da Aorta Torácica/mortalidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tomografia Computadorizada por Raios X/tendências , Resultado do Tratamento
16.
Biomacromolecules ; 17(8): 2701-9, 2016 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-27359245

RESUMO

Here we report the reversible addition-fragmentation chain transfer (RAFT) polymerization of acrylated epoxidized soybean oil (AESO), a cross-linker molecule, to high conversion (>50%) and molecular weight (>100 kDa) without macrogelation. Surprisingly, gelation is suppressed in this system far beyond the expectations predicated both on Flory-Stockmeyer theory and multiple other studies of RAFT polymerization featuring cross-linking moieties. By varying AESO and initiator concentrations, we show how intra- versus intermolecular cross-linking compete, yielding a trade-off between the degree of intramolecular linkages and conversion at gel point. We measured polymer chain characteristics, including molecular weight, chain dimensions, polydispersity, and intrinsic viscosity, using multidetector gel permeation chromatography and NMR to track polymerization kinetics. We show that not only the time and conversion at macrogelation, but also the chain architecture, is largely affected by these reaction conditions. At maximal AESO concentration, the gel point approaches that predicted by the Flory-Stockmeyer theory, and increases in an exponential fashion as the AESO concentration decreases. In the most dilute solutions, macrogelation cannot be detected throughout the entire reaction. Instead, cyclization/intramolecular cross-linking reactions dominate, leading to microgelation. This work is important, especially in that it demonstrates that thermoplastic rubbers could be produced based on multifunctional renewable feedstocks.


Assuntos
Reagentes de Ligações Cruzadas/química , Géis/química , Polímeros/química , Óleo de Soja/química , Ciclização , Cinética , Polimerização , Viscosidade
17.
Asian Pac J Trop Med ; 8(12): 1013-1021, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26706672

RESUMO

OBJECTIVE: To evaluate the antioxidant activity, antiglycation property, and bioactive components content of different solvent extracts from Chinese olive (Canarium album L.) fruit. METHODS: The dry powder of Chinese olive fruit was extracted with different solvents, i.e., water, water/ethanol (1/1, v/v), ethanol, methanol, acetone and ethyl acetate. The total phenolic, total flavonoids and total triterpenoids contents of various extracts were determined by spectrophotometric methods. Phenolic compounds were identified by high performance liquid chromatography. The assayed antioxidant activity was determined in vitro models such as antioxidant capacity by radical scavenging activity using 2,2'-Azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picryl- hydrazyl (DPPH) and nitrite oxide methods, chelating activity on metal ions, lipid and protein peroxidation methods. In vitro glucose-bovine serum albumin assay was used to evaluate the antiglycation of various extracts. RESULTS: The water/ethanol extracts of Chinese olive fruit exerted significant scavenging effects on free radicals and strong inhibitory effects on advanced glycation end products formation. The Chinese olive fruit extracts were rich in phenolic compounds and triterpenoids. Gallic acid, ferulic acid and rutin were identified from the water/ethanol extracts. Correlation analysis indicated that there was a linear relationship between the antioxidant potency, free radical scavenging ability and phenolic compounds content of the Chinese olive fruit extracts. CONCLUSIONS: Chinese olive fruit could be a natural candidate for studies of dietary complement to diabetes treatment since it combines antioxidant and antiglycation activities.

18.
J Agric Food Chem ; 63(42): 9232-8, 2015 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-26308886

RESUMO

This study investigates the effects of Trametes versicolor (L.:Fr.) Pilát (TVP, also known as Yunzhi) on bone properties in diabetic rats. Forty-five male Wistar rats (8 weeks old) were fed either a chow diet (control) or a high-fat diet throughout the study period of 28 days. Animals in the high-fat-diet group were injected with nicotinamide and streptozotocin to induce diabetes mellitus (DM). The DM rats were divided into a group receiving distilled water (vehicle) and another group receiving TVP at 0.1 g/kg weight by gavage. Relative to the vehicle group, TVP gavage lowered postprandial blood sugar (225 ± 18 mg/dL for TVP vs 292 ± 15 mg/dL for vehicle, p < 0.001) on day 26. Compared to the vehicle group, TVP mitigated DM-induced bone deterioration as determined by increasing bone volume of proximal tibia (22.8 ± 1.4% for TVP vs 16.8 ± 1.3% for vehicle, p = 0.003), trabecular number (p = 0.011), and femoral bone strength (11% in maximal load, 22% in stiffness, 14% in modulus, p < 0.001), and by reducing loss of femoral cortical porosity by 25% (p < 0.001). Our study demonstrates the protective effect of TVP on bone properties was mediated through, in part, the improvement of hyperglycemic control in DM animals.


Assuntos
Doenças Ósseas/prevenção & controle , Diabetes Mellitus Experimental/tratamento farmacológico , Extratos Vegetais/administração & dosagem , Polissacarídeos/administração & dosagem , Trametes/química , Animais , Fenômenos Biomecânicos , Glicemia/metabolismo , Doenças Ósseas/etiologia , Doenças Ósseas/fisiopatologia , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/metabolismo , Fêmur/química , Fêmur/fisiopatologia , Humanos , Masculino , Ratos , Ratos Wistar , Tíbia/química , Tíbia/fisiopatologia
19.
Int J Med Mushrooms ; 17(2): 141-50, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25746619

RESUMO

Xylaria nigripes, a local rare medicinal fungus, has multi-antioxidant activities owing to its water extraction as shown by previous research. However, the main indicator causing the antioxidant effect was not clear, so this research focused on the antioxidant activities from different sources of X. nigripes such as fruiting body polysaccharides, mycelium intracellular polysaccharides, mycelium extracellular polysaccharides, and their deproteinization products. The mycelium intracellular polysaccharide (XnIPS-1) from X. nigripes showed the highest reducing power of antioxidant activity, since it revealed the lowest IC50 values in all the assayed methodologies. The IC50 values of chelating ferrous ion ability, ABTS radical scavenging activity, and DPPH free radical scavenging were 1412, 174.25, and 351.56 µg/mL, respectively. In addition to these results, this research also explored the mechanism between polysaccharides and antioxidants compared by FT-IR analysis. The spectrum shows that the X. nigripes polysaccharide structure changed after the proteins were removed.


Assuntos
Antioxidantes/farmacologia , Produtos Biológicos/farmacologia , Polissacarídeos Fúngicos/farmacologia , Micélio/química , Xylariales/química , Benzotiazóis/metabolismo , Compostos de Bifenilo/metabolismo , Medicamentos de Ervas Chinesas/farmacologia , Estruturas Fúngicas/química , Concentração Inibidora 50 , Estrutura Molecular , Picratos/metabolismo , Ácidos Sulfônicos/metabolismo
20.
Int J Med Mushrooms ; 16(5): 431-47, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25271979

RESUMO

The optimal culture conditions were investigated to maximize the production of mycelial biomass and bioactive ingredients in submerged cultivation of Xylaria nigripes, a Chinese medicinal fungus. The one-factor-at-a-time method was used to explore the effects of medium components, including carbon, nitrogen, mineral sources, and initial pH of the medium and environmental factors, such as culture temperature and rotation speed, on mycelial growth and production of bioactive ingredients. The results indicated that the optimal culture temperature and rotation speed were 25°C and 100 rpm in a medium with 20 g fructose, 6 g yeast extract, and 2 g magnesiun sulfate heptahydrate as carbon, nitrogen, and mineral sources, respectively, in 1 L distilled water with an initial medium pH of 5.5. With optimal medium components and conditions of cultivation, the maximal production of mycelial biomass was 6.64 ± 0.88 g/L, with maximal production of bioactive ingredients such as extracellular polysaccharides (2.36 ± 0.18 mg/mL), intracellular polysaccharides (2.38 ± 0.07 mg/g), adenosine (43.27 ± 2.37 mg/g), total polyphenols (36.57 ± 1.36 mg/g), and triterpenoids (31.29 ± 1.17 mg/g) in a shake flask culture. These results suggest that different bioactive ingredients including intracellular polysaccharides, adenosine, total polyphenols and triterpenoids in mycelia and extracellular polysaccharides in broth can be obtained from one simple medium for submerged cultivation of X. nigripes.


Assuntos
Produtos Biológicos/metabolismo , Meios de Cultura/química , Micélio/crescimento & desenvolvimento , Micélio/metabolismo , Xylariales/crescimento & desenvolvimento , Xylariales/metabolismo , Biomassa , Concentração de Íons de Hidrogênio , Temperatura
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