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An impact polypropylene copolymer (IPC), composed of polypropylene (PP) and ethylene-propylene copolymer (EPC), was synthesized through two-stage in-reactor polymerization. A systematic investigation of the crystalline structure, thermal behavior, morphology, and tensile properties of the IPC extruded cast film was conducted. Specifically, the morphology of EPC was obtained by confocal Raman imaging by depicting the spatial distribution of the Raman band located at 1064 cm-1. The EPC phase exhibits fibrous morphology with the long axis aligning along the machine direction (MD). A three-dimensional (3D) heterogeneous structure of the IPC cast film obtained by confocal Raman imaging confirms that the fibrous EPC phase is dispersed in a 3D framework of the PP matrix. The mesomorphic phase in the as-prepared cast film transforms to a stable α-form crystal after annealing at 130 °C, which improves the yield strength but decreases the elongation of the cast film. The WAXD and SAXS results indicate that there is no obvious orientation of the crystallites. Thus, the anisotropy of tensile properties in the MD and transverse directions is closely related to the anisotropic phase morphology at the micrometer scale. The results reveal that the mechanical performances of IPC films are determined by the crystalline structure of the PP matrix and the morphology.
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We investigated the glassy dynamics of polystyrene (PS) confined in anodic aluminum oxide (AAO) nanopores by differential scanning calorimetry. Based on the outcome of our experiments, we show that the cooling rate applied to process the 2D confined PS melt has a significant impact on both the glass transition and the structural relaxation in the glassy state. A single glass transition temperature (Tg) is observed in quenched samples, while slow-cooled PS chains show two Tgs corresponding to a core-shell structure. The former phenomenon resembles what is observed in freestanding structures, while the latter is imputed to the adsorption of PS onto AAO walls. A more complex picture was drawn for physical aging. In the case of quenched samples, we observed a non-monotonic trend of the apparent aging rate that in 400 nm pores, reaches a value almost twice as larger than what is measured in bulk and decreases upon further confinement in smaller nanopores. For slow-cooled samples, by adequately varying the aging conditions, we were able to control the equilibration kinetics and either separate the two aging processes or induce an intermediate aging regime. We propose a possible explanation of these findings in terms of distribution in free volume and the presence of different aging mechanisms.
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The excellent combined properties of poly(butylene succinate) (PBS) make it a promising biodegradable plastic. However, the lack of functionality and low impact strength limit its application. Poly(dimethylsiloxane) (PDMS) was introduced to prepare new high-performance and functional poly(butylene succinate)-b-poly(dimethylsiloxane) (PBS-b-PDMS) in this work. The resulting PBS-b-PDMS was found to possess high molecular weight, narrow molecular weight distribution, and excellent combined performance. PBS-b-PDMS had good thermal properties. The decomposition temperature of 5% weight loss (T5%) increased from 324 to 344 °C, and the temperatures at the maximum weight loss rate (Tmax) values increased from 385.1 to 396.7 °C. The impact strength increased significantly from 7.8 kJ/m2 of PBS to 53.9 kJ/m2 of PBS-b-PDMS. As the PDMS block endows copolymers with low surface energy and good liquid resistance, PBS-b-PDMS has excellent antismudge, self-cleaning, and solvent resistance. Finally, to minimize the surface energy, PDMS blocks preferentially enrich the surface, which imparts the polymers with self-cleaning properties.
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Materiais Biocompatíveis , Polímeros , Humanos , Succinatos , Redução de PesoRESUMO
BACKGROUND: Most displaced femoral neck fractures can achieve satisfactory anatomical reduction by closed reduction, but there are still some that cannot reset satisfactorily after closed reduction, and open reduction are required. Such fractures that cannot be repositioned successfully by closed reduction are called irreducible displaced femoral neck fractures in this study. The objective of our study was to evaluate the efficacy of direct anterior incision with the Femoral Neck System in the treatment of irreducible displaced femoral fractures. METHODS: A total of 16 young and middle-aged patients with irreducible displaced femoral neck fractures involving Garden type III and IV were treated using Femoral Neck System fixation by open reduction through Direct Anterior Approach between January 2020 to September 2021. Functional outcomes and postoperative complications were assessed during follow-up. Clinical outcomes were evaluated by the Hip Harris score. The postoperative reduction was evaluated by the Garden Index. Observe postoperative complications. RESULTS: All patients were followed up with a mean follow-up time of 21.1(12-30) months, and according to radiological results, all patients achieved fracture healing, with a mean healing time of 4.25 months. All 16 patients received grade Garden I and II reductions, and there was no significant difference in the anteroposterior Garden reduction index between the first day after surgery (166.13 ± 5.61) and the 12th month after surgery(164.94 ± 4.49) (P>0.05) and no significant difference in lateral Garden index between the first day after surgery(171.06 ± 4.46) and the 12th month after surgery(169.38 ± 3.98) (P<0.05). According to the Hip Harris score scale, 13 patients received excellent and 3 patients received good. The postoperative Hip Harris Score(17.19 ± 4.8) was significantly higher than the preoperative score(92.19 ± 3.4), and the difference was statistically significant (P < 0.05). No or mild femoral neck shortness occurred in 12 (75%) patients, moderate shortening occurred in 3 (18.75%) patients, and severe shortening occurred in 1 (6.25%) patient. None of the patients experienced femoral head necrosis, fracture nonunion, or incision infection. One patient developed deep venous thrombosis of the lower extremity. CONCLUSIONS: The Direct Anterior Approach combined with Femoral Neck System is an excellent treatment for irreducible displaced femoral neck fracture and achieved good functional outcomes and anatomical reduction with low complications.
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Fraturas do Colo Femoral , Colo do Fêmur , Pessoa de Meia-Idade , Humanos , Fixação Interna de Fraturas/métodos , Fraturas do Colo Femoral/diagnóstico por imagem , Fraturas do Colo Femoral/cirurgia , Redução Aberta , Infecção da Ferida Cirúrgica , Resultado do Tratamento , Estudos RetrospectivosRESUMO
Crystallization of polymeric materials under nanoscopic confinement is highly relevant for nanotechnology applications. When a polymer is confined within rigid nanoporous anodic aluminum oxide (AAO) templates, the crystallization behavior experiences dramatic changes as the pore size is reduced, including nucleation mechanism, crystal orientation, crystallization kinetics, and polymorphic transition, etc. As an experimental prerequisite, exhaustive cleaning procedures after infiltrations of polymers in AAO pores must be performed to ensure producing an ensemble of isolated polymer-filled nanopores. Layers of residual polymers on the AAO surface percolate nanopores and lead to the so-called "fractionated crystallization", i.e., multiple crystallization peaks during cooling.Because the density of isolated nanopores in a typical AAO template exceeds the density of heterogeneities in bulk polymers, the majority of nanopores will be heterogeneity-free. This means that the nucleation will proceed by surface or homogeneous nucleation. As a consequence, a very large supercooling is necessary for crystallization, and its kinetics is reduced to a first-order process that is dominated by nucleation. Self-nucleation is a powerful method to exponentially increase nucleation density. However, when the diameter of the nanopores is lower than a critical value, confinement prevents the possibility to self-nucleate the material.Because of the anisotropic nature of AAO pores, polymer crystals inside AAO also exhibit anisotropy, which is determined by thermodynamic stability and kinetic selection rules. For low molecular weight poly(ethylene oxide) (PEO) with extended chain crystals, the orientation of polymer crystals changes from the "chain perpendicular to" to the "chain parallel to" the AAO pore axis, when the diameter of AAO decreases to the contour length of the PEO, indicating the effect of thermodynamic stability. When the thermodynamic requirement is satisfied, the orientation is determined by kinetics including crystal growth direction, nucleation, and crystal growth rate. An orientation diagram has been established for the PEO/AAO system, considering the cooling condition and pore size.The interfacial polymer layer has different physical properties as compared to the bulk. In poly(l-lactic acid), the relationship between the segmental mobility of the interfacial layer and crystallization rate is established. For the investigation of polymorphic transition of poly(butane-1), the results indicate that a 12 nm interfacial layer hinders the transition of Form II to Form I. Block and random copolymers have also been infiltrated into AAO nanopores, and their crystallization behavior is analogously affected as pore size is reduced.
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BACKGROUND: The surgical treatment of complex acetabular fractures is one of the most challenging procedures for orthopedic surgeons. The Pararectus approach, as a reasonable alternative to the existing surgical procedures, was performed for the treatment of acetabular fractures involving the anterior column. This study aimed to evaluate outcome using the Pararectus approach for acetabular fractures involving anterior columns. METHODS: Thirty-seven with displaced acetabular fractures involving anterior columns were treated between July 2016 and October 2019 using the Pararectus approach. The functional outcomes (using the Merle d Aubigné and Postel scoring system, WOMAC and modified Harris scoring), the quality of surgical reduction (using the Matta criteria), and postoperative complications were assessed during approximately 26 months follow-up period. RESULTS: Thirty-seven patients (mean age 53 years, range: 30-71; 28 male) underwent surgery. Mean intraoperative blood loss was 840 ml (rang: 400-2000 ml) and mean operating time was 210 min (rang: 140-500 min). The modified Merle d Aubigné score was excellent and good in 27 cases (73%), fair in 6 cases (16%), and poor in 3 cases (11%). The mean score was 88.5 (range:77-96) for the modified Harris Hip scores, and 22 (range:7-35) for the WOMAC scores after operation. Postoperative functional outcomes were significantly improved compared with preoperative outcomes (P < 0.0001). The quality of reduction was anatomical in 21 cases (57%), satisfactory in 9 cases (24%), and unsatisfactory in 7 cases (19%). At follow-up, four patients developed a DVT, and heterotopic bone formation was observed in one patient. The hip osteoarthritis was not observed. CONCLUSION: The Pararectus approach achieved good functional outcomes and anatomical reduction in the treatment of acetabular fractures involving anterior column with minimal access morbidity.
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Fraturas Ósseas , Fraturas do Quadril , Lesões do Pescoço , Fraturas da Coluna Vertebral , Acetábulo/diagnóstico por imagem , Acetábulo/lesões , Acetábulo/cirurgia , Feminino , Fixação Interna de Fraturas/efeitos adversos , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/cirurgia , Fraturas do Quadril/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do TratamentoRESUMO
BACKGROUND: The surgical treatment of high-grade acromioclavicular joint dislocation remains a matter of debate. Clavicular hook plate internal fixation was widely used in the treatment of acromioclavicular dislocation because of its easy-to-master surgical technique. This study aimed to evaluate outcomes using hook plate fixation for acromioclavicular dislocation. METHODS: A consecutive series of 57 patients with acute acromioclavicular joint dislocation involving Rockwood type V were treated between November 2013 and September 2019 using hook plate fixation. The functional outcomes (using the visual analogue score, Constant-Murley score, and University of California Los Angeles score), the quality of surgical reduction (using the coracoclavicular distance), and post-operative complications were assessed with about 46 months of follow-up. RESULTS: The mean Constant-Murley score increased from 72.6 before surgery to 87.6 at final follow-up. The mean University of California Los Angeles score was 14.1 pre-operatively and 31.6 at final follow-up. Meanwhile, the visual analogue scores were significantly reduced from 3.4 pre-operatively to 1.3 post-operatively. The coracoclavicular distance decreased from 19.4 mm pre-operatively to 10.9 mm at the last follow-up. Post-operative functional and radiological outcomes were significantly improved compared with pre-operative outcomes (P < 0.01). The overall excellent and good result was 35.1% (20/57) and 54.1% (31/57), respectively. At follow-up, the overall complication rate was 15.8% (9/57) including subacromial impingement (three patients), acromial osteolysis (three patients), reduction loss (one patient), acromioclavicular joint osteoarthritis (one patient), and calcification (one patient). CONCLUSION: Hook plate fixation was a viable treatment approach, and achieved good clinical outcomes in the treatment of acute acromioclavicular dislocation involving V. But some complications of hook plate fixation should not be ignored.
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Articulação Acromioclavicular , Doenças Ósseas , Luxações Articulares , Luxação do Ombro , Articulação Acromioclavicular/diagnóstico por imagem , Articulação Acromioclavicular/cirurgia , Placas Ósseas/efeitos adversos , Humanos , Luxações Articulares/diagnóstico por imagem , Luxações Articulares/cirurgia , Luxação do Ombro/cirurgia , Resultado do TratamentoRESUMO
The non-invasive brain-computer interface (BCI) has gradually become a hot spot of current research, and it has been applied in many fields such as mental disorder detection and physiological monitoring. However, the electroencephalography (EEG) signals required by the non-invasive BCI can be easily contaminated by electrooculographic (EOG) artifacts, which seriously affects the analysis of EEG signals. Therefore, this paper proposed an improved independent component analysis method combined with a frequency filter, which automatically recognizes artifact components based on the correlation coefficient and kurtosis dual threshold. In this method, the frequency difference between EOG and EEG was used to remove the EOG information in the artifact component through frequency filter, so as to retain more EEG information. The experimental results on the public datasets and our laboratory data showed that the method in this paper could effectively improve the effect of EOG artifact removal and improve the loss of EEG information, which is helpful for the promotion of non-invasive BCI.
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Artefatos , Interfaces Cérebro-Computador , Humanos , Eletroculografia/métodos , Algoritmos , Eletroencefalografia/métodos , Processamento de Sinais Assistido por ComputadorRESUMO
Biomedical applications of polymers require precise control of the solid-state structure, which is of particular interest for biodegradable copolymers. In this work, we evaluated the influence of crystallization conditions on the comonomer exclusion/inclusion balance of biodegradable poly(butylene succinate-ran-butylene adipate) (PBSA) isodimorphic random copolymers. Regardless of the crystallization conditions, the copolymers retain their isodimorphic character, displaying a pseudo-eutectic behavior with crystallization in the entire composition range. This illustrates the thermodynamic nature of the isodimorphic behavior for PBSA random copolymers. However, depending on the composition, the crystallization conditions affect the exclusion/inclusion balance of the comonomers. Fast cooling favors butylene adipate (BA) inclusion inside the poly(butylene succinate) (PBS) crystals, whereas isothermal crystallization strongly limits it. PBA-rich compositions behave differently. Both fast and slow crystallization formed the ß-phase, whereas BS unit inclusion is favored independently of the cooling conditions. During successive self-nucleation and annealing, the BA inclusion is intermediate between non-isothermal and isothermal conditions, while the crystalline structure of the PBA phase changes from the ß-phase to the more stable α-phase. We propose a simple crystallographic model to explain the changes in the unit cell dimension of the copolymers.
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Adipatos , Polímeros , Alcenos , Butileno Glicóis , Cristalização , SuccinatosRESUMO
While a relatively complete understanding of the nucleation and orientation of polymers under confinement in one-dimensional nanochannels has been achieved, crystallization kinetics investigation of confined polymers is still rare. In this work, we investigated the crystallization kinetics of poly(ethylene oxide) confined in anodic alumina oxide templates with different pore sizes using in situ wide-angle X-ray scattering (WAXS). The crystallization kinetics results were fitted with the Avrami equation. The Avrami index was determined by both "isothermal step crystallization" and in situ WAXS. The crystallization process of polymers under one-dimensional nanopore confinement was simulated by a "one-dimensional lattice model". Based on this model, it is shown that homogeneous nucleation with the simultaneous growth of multiple crystal planes with drastically different growth rates could result in Avrami indexes lower than 1.
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This work describes the successful melt infiltration of poly(butylene succinate) (PBS) and poly(butylene adipate) (PBA) within 70 nm diameter anodic aluminum oxide (AAO) templates. The infiltrated samples were characterized by SEM, Raman, and FTIR spectroscopy. The crystallization behaviors and crystalline structures of both polymers, bulk and confined, were analyzed by differential scanning calorimetry (DSC) and grazing incidence wide angle X-ray scattering (GIWAXS). DSC revealed that a change in the nucleation process occurred from heterogeneous nucleation for bulk samples to homogeneous nucleation for infiltrated PBA and to surface-induced nucleation for infiltrated PBS. GIWAXS results indicate that PBS nanofibers crystallize in the α-phase, as well as their bulk samples. However, PBA nanofibers crystallize just in the ß-phase, whereas PBA bulk samples crystallize in a mixture of α- and ß-phases. The crystal orientation within the pores was determined, and differences between PBS and PBA were also found. Finally, broadband dielectric spectroscopy was applied to study the segmental dynamics for bulk and infiltrated samples. The glass temperature was found to significantly decrease in the PBS case upon infiltration, while that of PBA remained unchanged. These differences were correlated with the higher affinity of PBS to the AAO walls than PBA, in accordance with their nucleation behavior (surface-induced versus homogeneous nucleation, respectively).
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BACKGROUND: Knee osteoarthritis (OA) is one of the most common joint diseases, and pharmacotherapy is necessary to control its symptoms. AIM: To evaluate efficacy and tolerability of duloxetine in patients with knee OA. METHODS: PubMed, Web of Science, Embase, Cochrane Library and ClinicalTrials.gov were searched to identify randomised controlled trials comparing duloxetine with placebo for knee OA. Data including pain, stiffness, physical function, and adverse events were extracted for meta-analysis. The protocol was prospectively registered in PROSPERO (CRD42018097110). RESULTS: Data from six randomised controlled trials including 2059 participants were pooled. Duloxetine achieved significant reductions in primary outcomes including Brief Pain Inventory 24-h average pain score (weighted mean difference (WMD) = -0.74, 95% confidence interval (CI) = -0.92 to -0.57), weekly mean of the 24-h average pain score (WMD = -0.76, 95% CI = -0.96 to -0.56), WOMAC stiffness score (WMD = -0.47, 95% CI = -0.60 to -0.34) and WOMAC physical function score (WMD = -4.44, 95% CI = -5.24 to -3.64). Furthermore, duloxetine demonstrated a higher number of treatment-emergent adverse events (risk ratio (RR) = 1.31, 95% CI = 1.20-1.44) and discontinuations (RR = 2.26, 95% CI = 1.63-3.12); however, no difference in serious adverse events (RR = 0.92, 95% CI = 0.40-2.11) was observed. CONCLUSION: Duloxetine is effective in the management of chronic pain and loss of physical function in knee OA with acceptable adverse events despite having no advantage in treating joint stiffness. Future trials should focus on determining the optimal treatment regimen.
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Analgésicos/uso terapêutico , Cloridrato de Duloxetina/uso terapêutico , Osteoartrite do Joelho/tratamento farmacológico , Manejo da Dor/métodos , Humanos , Osteoartrite do Joelho/fisiopatologia , Medição da Dor , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
The longan industry produces a large amount of byproducts such as pericarp and seed, resulting in environmental pollution and resource wastage. The present study was performed to systematically evaluate functional components, i.e., polyphenols (phenolics and flavonoids) and alkaloids, in longan byproducts and their bioactivities, including antioxidant activities, nitrite scavenging activities in simulated gastric fluid and anti-hyperglycemic activities in vitro. Total phenolic and total flavonoid contents in pericarp were slightly higher than those in seeds, but seeds possessed higher alkaloid content than pericarp. Four polyphenolic substances, i.e., gallic acid, ethyl gallate, corilagin and ellagic acid, were identified and quantified using high-performance liquid chromatography. Among these polyphenolic components, corilagin was the major one in both pericarp and seed. Alkaloid extract in seed showed the highest DPPH radical scavenging activity and oxygen radical absorbance capacity. Nitrite scavenging activities were improved with extract concentration and reaction time increasing. Flavonoids in seed and alkaloids in pericarp had potential to be developed as anti-hyperglycemic agents. The research result was a good reference for exploring longan byproducts into various valuable health-care products.
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Alcaloides/análise , Polifenóis/análise , Sapindaceae/química , Alcaloides/farmacologia , Antioxidantes/análise , Antioxidantes/farmacologia , Cromatografia Líquida de Alta Pressão , Hipoglicemiantes/análise , Hipoglicemiantes/farmacologia , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Sementes/químicaRESUMO
No consensus had been reached about the optimal treatment for syndesmotic fixation. We performed a review of randomized controlled trials (RCTs) to assist in clarifying many of the controversies that were debated for years despite new technology and options. PubMed, Embase, and the Cochrane Library were searched through specific terms and limits. Only RCTs were selected for final inclusion. Study screening and data extraction were performed independently by 2 reviewers. Thirteen RCTs, including 828 cases, met the inclusion criteria and are summarized in this review. Pooled results demonstrated that dynamic fixation had better functional outcomes as well as lower rates of malreduction and complications compared with syndesmotic screw fixation. Both absorbable screw and tricortical screw fixation showed similar results to quadricortical metallic screws. Therefore, dynamic fixation is recommended for the treatment of syndesmosis injuries.
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Fraturas do Tornozelo/cirurgia , Implantes Absorvíveis , Parafusos Ósseos , Fixação Interna de Fraturas/métodos , Humanos , Dispositivos de Fixação Ortopédica , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
PURPOSE: The purpose of this study was to evaluate the efficacy of an extracellular matrix scaffold with multilayer decellularized tendon slices (MDTSs) for reconstructing large rotator cuff tears in a rabbit model. METHODS: Large defects in the infraspinatus tendons were created bilaterally in 36 rabbits. The graft group underwent bridging repair of the defects with the MDTSs grafts from Achilles tendons of adult beagle dogs, and the control group underwent repair with the autologous excised tendon. Specimens underwent histologic observation, biomechanical testing, and microcomputed tomography analysis at 2, 4, and 8 weeks after surgery. RESULTS: Histologic analysis confirmed that the MDTSs graft promoted cell ingrowth and tissue integration, and fibrocartilage and Sharpey fibers formed at the enthesis at 8 weeks. Accordingly, the MDTSs graft generated a histologic appearance similar to that of the autogenous tendon graft. Mechanical testing revealed a significant increase of the regenerated tendons in ultimate load and stiffness from 4 to 8 weeks postoperatively, which was similar to autologous tendon repair. Microcomputed tomography analysis demonstrated that the MDTSs graft promoted bone formation at the tendon-bone insertion, thus improving the mechanical properties of the repair tendon. CONCLUSIONS: The MDTSs graft used to bridge large rotator cuff defects in a rabbit model promoted host cell ingrowth, enhanced the remodeling of regenerated tendon, and promoted fibrocartilage formation, thus improving the biomechanical properties of the repaired tendon. This study thereby provides fundamental information for rotator cuff regeneration with the MDTSs graft. CLINICAL RELEVANCE: Rotator cuff regeneration using MDTSs grafts is a promising procedure for large rotator cuff tears.
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Tendão do Calcâneo/transplante , Matriz Extracelular , Lesões do Manguito Rotador/cirurgia , Alicerces Teciduais , Tendão do Calcâneo/diagnóstico por imagem , Tendão do Calcâneo/fisiologia , Animais , Modelos Animais de Doenças , Cães , Fibrocartilagem/fisiologia , Regeneração Tecidual Guiada , Masculino , Osteogênese , Coelhos , Lesões do Manguito Rotador/diagnóstico por imagem , Resistência à Tração , Cicatrização , Microtomografia por Raio-XRESUMO
How polymers crystallize can greatly affect their thermal and mechanical properties, which influence the practical applications of these materials. Polymeric materials, such as block copolymers, graft polymers, and polymer blends, have complex molecular structures. Due to the multiple hierarchical structures and different size domains in polymer systems, confined hard environments for polymer crystallization exist widely in these materials. The confined geometry is closely related to both the phase metastability and lifetime of polymer. This affects the phase miscibility, microphase separation, and crystallization behaviors and determines both the performance of polymer materials and how easily these materials can be processed. Furthermore, the size effect of metastable states needs to be clarified in polymers. However, scientists find it difficult to propose a quantitative formula to describe the transition dynamics of metastable states in these complex systems. Normal alkanes [CnH2n+2, n-alkanes], especially linear saturated hydrocarbons, can provide a well-defined model system for studying the complex crystallization behaviors of polymer materials, surfactants, and lipids. Therefore, a deeper investigation of normal alkane phase behavior in confinement will help scientists to understand the crystalline phase transition and ultimate properties of many polymeric materials, especially polyolefins. In this Account, we provide an in-depth look at the research concerning the confined crystallization behavior of n-alkanes and binary mixtures in microcapsules by our laboratory and others. Since 2006, our group has developed a technique for synthesizing nearly monodispersed n-alkane containing microcapsules with controllable size and surface porous morphology. We applied an in situ polymerization method, using melamine-formaldehyde resin as shell material and nonionic surfactants as emulsifiers. The solid shell of microcapsules can provide a stable three-dimensional (3-D) confining environment. We have studied multiple parameters of these microencapsulated n-alkanes, including surface freezing, metastability of the rotator phase, and the phase separation behaviors of n-alkane mixtures using differential scanning calorimetry (DSC), temperature-dependent X-ray diffraction (XRD), and variable-temperature solid-state nuclear magnetic resonance (NMR). Our investigations revealed new direct evidence for the existence of surface freezing in microencapsulated n-alkanes. By examining the differences among chain packing and nucleation kinetics between bulk alkane solid solutions and their microencapsulated counterparts, we also discovered a mechanism responsible for the formation of a new metastable bulk phase. In addition, we found that confinement suppresses lamellar ordering and longitudinal diffusion, which play an important role in stabilizing the binary n-alkane solid solution in microcapsules. Our work also provided new insights into the phase separation of other mixed system, such as waxes, lipids, and polymer blends in confined geometry. These works provide a profound understanding of the relationship between molecular structure and material properties in the context of crystallization and therefore advance our ability to improve applications incorporating polymeric and molecular materials.
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PURPOSE: Although varieties of surgical repair techniques and materials have been used to repair rotator cuff defects, re-tearing frequently occurs. The purpose of this study is to evaluate the postoperative outcomes of rotator cuff repairs with a decellularized tendon slices (DTSs) graft in a rabbit model. METHODS: Large defects in the infraspinatus tendons were created bilaterally in 21 rabbits. The graft group underwent reconstruction of the defects with the DTSs grafts, while the defect group did not undergo any treatment. The specimens underwent histological observation, biomechanical testing, and magnetic resonance imaging (MRI) detection at 4, 8, and 12 weeks after surgery. In addition, 2 rabbits that were not operated on were used for MRI detection as a normal reference. RESULTS: Histological analysis revealed that the graft promoted host cell ingrowth and tissue integration, and a tendon-like structure developed at 12 weeks. The ultimate tensile load had a significant difference between specimens at 4 and 12 weeks in the graft group, but there was no significant difference between the graft group and the defect group. In the graft group, the stiffness at 12 weeks was significantly greater than that at 4 or 8 weeks, and it was also greater than the stiffness in the defect group at 12 weeks. MRI demonstrated that the signal strength of the regenerative tissue from the graft group at 12 weeks was similar to that of normal infraspinatus tendon. CONCLUSION: The DTSs graft allowed for incorporation of host tendon and improved the biomechanical performance of the regenerative tendon. Therefore, the graft could be a promising bioscaffold to enhance the surgical repair of large rotator cuff defects and consequently improve the clinical outcome of rotator cuff tears.
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Manguito Rotador/cirurgia , Traumatismos dos Tendões/cirurgia , Transferência Tendinosa/métodos , Tendões/transplante , Animais , Modelos Animais de Doenças , Masculino , Coelhos , Lesões do Manguito Rotador , RupturaRESUMO
BACKGROUND: Recent studies have demonstrated that the CC chemokine receptor 6 (CCR6) may be involved in tumorigenesis and tumor progression of various human malignancies. The aim of this study was to investigate the clinical significance and prognostic value of CCR6 expression in human hepatocellular carcinoma (HCC). METHODS: CCR6 protein levels were evaluated by Western blot in samples from 25 HCC and matched adjacent noncancerous liver tissues. CCR6 protein expression levels were also examined by immunohistochemistry in association with clinicopathologic features and prognosis in 212 HCC patients. The effects of CCR6 on HCC cell proliferation and invasion were examined in vitro. RESULTS: Western blot analysis showed significantly higher CCR6 protein in HCC than that in matched adjacent noncancerous liver tissues. By immunohistochemistry, CCR6 expression correlated with multicentricity (P = 0.014) and vascular invasion (P = 0.009). Importantly, CCR6 expression was an independent prognostic factor for the overall survival of HCC patients [hazard ratio = 3.07, 95% confidence interval (CI) = 1.94-4.76, P = 0.013]. In vitro data revealed that CCR6 promoting HCC cell proliferation through regulating p21, p27, and cyclin D1. CONCLUSIONS: CCR6 could be used as a molecular marker to predict prognosis for HCC. J. Surg. Oncol. 2014; 110:151-155. © 2014 Wiley Periodicals, Inc.
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Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/metabolismo , Neoplasias Hepáticas/metabolismo , Receptores CCR6/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Western Blotting , Carcinoma Hepatocelular/mortalidade , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Proliferação de Células , Feminino , Seguimentos , Humanos , Imuno-Histoquímica , Estimativa de Kaplan-Meier , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/patologia , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Prognóstico , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taxa de SobrevidaRESUMO
Cross-linked Fe(III)-chitosan composite (Fe-CB) was used as the adsorbent for removing perchlorate from the aqueous solution. The adsorption experiments were carried out by varying contact time, initial concentrations, temperatures, pH, and the presence of co-existing anions. The morphology of the adsorbent was discussed using FT-IR and SEM with X-EDS analysis. The pH ranging from 3.0-10.2 exhibited very little effect on the adsorption capability. The perchlorate uptake onto Fe-CB obeyed Langmuir isotherm model. The adsorption process was rapid and the kinetics data obeyed the pseudo second-order model well. The eluent of 2.5% (W/V) NaCl could regenerate the exhausted adsorbent efficiently. The adsorption mechanism was also discussed.
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Quitosana/química , Compostos Férricos/química , Percloratos/isolamento & purificação , Poluentes Químicos da Água/isolamento & purificação , AdsorçãoRESUMO
We propose a methodology to characterize the crystalline content of interfacial polymer layers in systems confined at the nanoscale level in a 2D geometry. Based on the crystallinity data of a set of polymers, we introduce a simple model to describe the gradient in crystallinity introduced by confining polymer chains in nanopores. Our model underscores the pivotal role that interfaces play in crystallization and unequivocally contradicts the existence of interfacial "dead" layers where crystallization cannot take place. Further, we verified that the organization of crystals near the pore walls resembles the macromolecular architecture of adsorbed layers, hinting at a strong interplay between crystallization and adsorption.