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1.
J Environ Manage ; 370: 123002, 2024 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-39454379

RESUMO

Inoculating sulfate-reducing bacteria (SRB) habitats offers an eco-friendly method for treating sulfate-metal laden wastewater, characterized by high sulfate levels, low pH, and elevated heavy metals. This study optimizes source habitat selection of SRB by evaluating groundwater, sewage sludge, and lake sediment, focusing on their suitability and adaptability to aerobic-anaerobic transitions in industrial settings. Sewage sludge, with its slightly acidic pH, reducing environment, and high nutrient levels (Total organic carbon: 207.53 g kg-1, Total nitrogen: 47.12 g kg-1), provides robust SRB potential, as supported by its highest diversity index. However, heavy metals and polycyclic aromatic hydrocarbons pose application challenges. All habitats effectively reduced metal concentrations anaerobically, with Cu removal reaching 95%-99%, and groundwater achieved the highest chemical oxygen demand reduction (63.6%) aerobically. Sludge and sediment showed high biomass and extracellular polymeric substances (EPS) accumulation, while groundwater's nucleic acid-rich EPS enhanced metal immobilization, resulting in stable residual metal forms but with potential remobilization under oxidative conditions. Microbial analysis revealed that Proteobacteria and Firmicutes were key players during transitions, with the highest SRB abundance in groundwater. SRB composition varied across habitats, with Sedimentibacter (13.04%), Desulfovibrio (6.33%), and Desulfomonile (8.1%) dominating in groundwater, sludge, and sediment, respectively, during the anaerobic stage. Functional analysis highlighted sludge's persistence in sulfate reduction under aerobic conditions, while groundwater's limited nitrogen cycle involvement indicated broader biogeochemical limitations. Collectively, these findings highlight strengths and limitations of each habitat as SRB inoculum source, emphasizing the importance of tailored anaerobic-to-aerobic strategies for effective wastewater management.

2.
Phys Chem Chem Phys ; 25(16): 11176-11184, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37039244

RESUMO

Photoactivated fluorophores (PAFs) are powerful imaging tools for observing subcellular structures and tracking dynamic biological processes. However, photoremovable protecting groups (PPGs) widely used to construct PAFs suffer from the drawbacks of short-wavelength excitation and/or low photolysis efficiency. Herein, a class of coumarin-based PPGs with electron-rich thiophene derived substitutions at the C3-position of a coumarin scaffold were prepared. The modification not only leads to the redshift of the absorption band to the blue light region (400-500 nm), but also the increases of uncaging quantum yield (Φu) as well as molar extinction coefficient (εmax), thus enhancing the photolysis efficiency (Φu × Îµmax) up to 34.2 × 103 M-1 cm-1. The exceptionally high photolysis efficiency enables efficient photolysis in blue light as weak as 2 mW cm-2 or in blue light from a Luminol chemiluminescence system. Based on the excellent photolysis properties, the PAF constructed by the new PPG exhibits fast photoactivation and a low background signal, and the resulting fluorescence images display a signal-to-noise ratio greater than 780. It is anticipated that the superior photolysis performance makes the PPGs a novel platform for the construction of photo responsive systems in a variety of applications.

3.
Angew Chem Int Ed Engl ; 62(37): e202308793, 2023 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-37496468

RESUMO

Liquid-crystal elastomers (LCEs) capable of performing large and reversible deformation in response to an external stimulus are an important class of soft actuators. However, their manufacturing process typically involves a multistep approach that requires harsh conditions. For the very first time, LCEs with customized geometries that can be manufactured by a rapid one-step approach at room temperature are developed. The LCEs are hydrogen bond (H-bond) crosslinked main chain polymers comprising flexible short side chains. Applying a stretching/shear force to the LCE can simultaneously induce mesogen alignment and H-bond exchange, allowing for the formation of well-aligned LCE networks stabilized by H-bonds. Based on this working principle, soft actuators in fibers and 2D/3D objects can be manufactured by mechanical stretching or melt extrusion within a short time (e.g. <1 min). These actuators can perform reversible macroscopic motions with large, controlled deformations up to 38 %. The dynamic nature of H-bonds also provides the actuators with reprocessability and reprogrammability. Thus, this work opens the way for the one-step and custom manufacturing of soft actuators.

4.
Macromol Rapid Commun ; 43(23): e2200538, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36056702

RESUMO

Carbon fiber reinforced polymer (CFRP) composites are indispensable in a variety of applications, because of their high specific strength. CFRPs are generally constructed by carbon fibers as reinforcements and crosslinked polymers as binders. Due to the irreversible nature of the crosslinked polymers, CFRPs are neither repairable nor recyclable. Once the material is damaged or out of service, landfill or incineration is the typical way to deal with the waste. These methods take no advantages of the residue value of the waste and add burdens to the environment. To reduce waste and cost, it is desirable to develop effective recycling technologies to reserve the residue value of carbon fiber and polymer matrix. In the past decade, chemical recycling by cleaving the covalent bonds in a solvent has been considered as an ideal path for the recycling of CFRP wastes, because it has the potential to recover both valuable CFs and polymer matrix. In this review, the discussion is focused on the progress in the chemical recycling of CFRP. The primary matrix resin of CFRP discussed in this review is epoxy resin which is the most widely used polymer matrix. In addition, the challenges and outlook are provided.

5.
BMC Musculoskelet Disord ; 23(1): 6, 2022 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-34980080

RESUMO

BACKGROUND: Pedicle screw invasion of the proximal articular process will cause local articular process degeneration and acceleration, which is an important factor affecting adjacent segment degeneration. Although lumbar spondylolisthesis is a risk factor for screw invasion of the proximal joint, there is no clear conclusion regarding the two different types of spondylolisthesis. Therefore, the purpose of this study was to explore the influence of pedicle screw placement on proximal facet invasion in the treatment of degenerative spondylolisthesis and isthmic spondylolisthesis. METHODS: In total, 468 cases of lumbar spondylolisthesis treated by decompression and fusion in our hospital from January 2017 to January 2020 were included in this retrospective study. Among them, 238 cases were degenerative spondylolisthesis (group A), and 230 cases were isthmic spondylolisthesis (group B). Sex, age, body mass index, bone mineral density, preoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) scores, postoperative VAS and ODI scores at 1 month and 3 months, and angle of the proximal facet joint at the last follow-up were recorded and compared between the two groups. The degree of pedicle screw invasion of the proximal facet joint was graded and compared by the SEO grading method. RESULTS: There were no significant differences in sex, age, body mass index, bone mineral density, preoperative VAS and ODI scores, or proximal facet joint angle between the two groups (P > 0.05). There was no significant difference in VAS and ODI scores between the two groups at 1 month and 3 months after the operation (P > 0.05). The VAS score of group A at the last follow-up was 1 (1,2). The VAS score of group B at the last follow-up was 3 (1,3). The ODI score of group A at the last follow-up was 6(4,26). The ODI score of group B at the last follow-up was 15(8,36). The VAS and ODI scores of the two groups at the last follow-up were significantly different (P < 0.05). According to the SEO grading method, the invasion of the proximal articular process by pedicle screw placement in group A involved 320 cases in grade 0, 128 cases in grade I and 28 cases in grade II. In group B, there were 116 cases in grade 0, 248 cases in grade I and 96 cases in grade II, with a significant difference (P < 0.01). CONCLUSION: In summary, a certain number of cases involving screws invading the proximal facet joint occurred in the two different types of lumbar spondylolisthesis, but the number in the isthmic spondylolisthesis group was significantly higher than that in the degenerative spondylolisthesis group, which caused more trauma to the proximal facet joint and significantly affected the patient prognosis.


Assuntos
Parafusos Pediculares , Fusão Vertebral , Espondilolistese , Humanos , Lactente , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Estudos Retrospectivos , Fusão Vertebral/efeitos adversos , Espondilolistese/diagnóstico por imagem , Espondilolistese/cirurgia , Resultado do Tratamento
6.
BMC Musculoskelet Disord ; 23(1): 39, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34991578

RESUMO

BACKGROUND: To analyze the risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery. METHODS: From January 2019 to January 2021, 1794 patients with lumbar degenerative disease, such as lumbar disc herniation, lumbar spinal stenosis and lumbar spondylolisthesis, were treated at our hospital. In all, 1221 cases were included. General data (sex, age, BMI), bone mineral density, proximal facet joint angle, degenerative lumbar spondylolisthesis, isthmic lumbar spondylolisthesis and fixed segment in the two groups were recorded. After the operation, vertebral CT of the corresponding surgical segments was performed for three-dimensional reconstruction and evaluation of whether the vertebral arch root screw interfered with the proximal facet joint. The included cases were divided into an invasion group and a noninvasion group. Univariate analysis was used to screen the risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery, and the selected risk factors were included in the logistic model for multivariate analysis. RESULTS: The single-factor analysis showed a significant difference in age, BMI, proximal facet joint angle, degenerative lumbar spondylolisthesis, and fixed segment (P < 0.1). Multifactor analysis of the logistic model showed a significant difference for age ≥ 50 years (P < 0.001, OR = 2.291), BMI > 28 kg/m2 (P < 0.001, OR = 2.548), degenerative lumbar spondylolisthesis (P < 0.001, OR = 2.187), gorge cleft lumbar relaxation (P < 0.001, OR = 2.410), proximal facet joint angle (35 ~ 45°: P < 0.001, OR = 3.151; > 45°: P < 0.001, OR = 3.578), and fixed segment (lower lumbar spine: P < 0.001, OR = 2.912). CONCLUSION: Age (≥ 50 years old), BMI (> 28 kg/m2), proximal facet joint angle (35 ~ 45°, > 45°), degenerative lumbar spondylolisthesis, isthmic lumbar spondylolisthesis and fixed segment (lower lumbar spine) are independent risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery. Compared with degenerative lumbar spondylolisthesis, facet joint intrusion is more likely in isthmic lumbar spondylolisthesis.


Assuntos
Parafusos Pediculares , Fusão Vertebral , Espondilolistese , Articulação Zigapofisária , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Pessoa de Meia-Idade , Análise Multivariada , Fusão Vertebral/efeitos adversos , Espondilolistese/diagnóstico por imagem , Espondilolistese/cirurgia , Articulação Zigapofisária/diagnóstico por imagem , Articulação Zigapofisária/cirurgia
7.
BMC Surg ; 22(1): 189, 2022 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-35568832

RESUMO

BACKGROUND: This study aimed to analyze the risk factors for proximal junctional kyphosis (PJK) for patients with chronic symptomatic osteoporotic thoracolumbar fractures (CSOTLF) and kyphosis who underwent long-segment internal fixation. METHODS: We retrospectively reviewed the records of patients with CSOTLF complicated with kyphosis who underwent posterior multilevel internal fixation in our hospital between January 2013 and January 2020. The patients' age, sex, body mass index (BMI), bone mineral density (BMD), smoking status, cause of injury, comorbidities, injury segments, and American Spinal Injury Association (ASIA) grading non-surgical data; posterior ligament complex (PLC) injury, upper and lower instrumented vertebral position (UIV and LIV, respectively), number of fixed segments surgical data, proximal junctional angle (PJA), sagittal vertebral axis (SVA), pelvic incidence (PI), lumbar lordosis (LL), pelvic incidence-lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), and sacral slope (SS) surgical indicators were collected. Patients were divided into postoperative PJK and non-PJK groups. RESULTS: This study included 90 patients; among them, 30 (31.58%) developed PJK postoperatively. All patients were followed up for > 24 months (mean 32.5 months). Univariate analysis showed significant differences in age, BMI, BMD, PLC injury, UIV, and LIV fixation position, number of fixation stages, and preoperative PJA, SVA, PI-LL, and SS between the two groups (P < 0.05). Additionally, no significant differences were observed in sex, smoking, cause of injury, complications, injury segment ASIA grade, and preoperative PT between the two groups (P > 0.05). Multifactorial logistic regression analysis showed that age > 70 years (OR = 32.279, P < 0.05), BMI > 28 kg/m2 (OR = 7.876, P < 0.05), BMD T value < - 3.5 SD (OR = 20.836, P < 0.05), PLC injury (OR = 13.981, P < 0.05), and preoperative PI-LL > 20° (OR = 13.301, P < 0.05) were risk factors for PJK after posterior long-segment internal fixation in elderly patients with CSOTLF complicated with kyphosis. CONCLUSION: CSOTLF patients undergoing posterior long segment internal fixation are prone to PJK, and age > 70 years, BMI > 28 kg/m2, BMD T value < - 3.5 SD, preoperative PI-LL > 20° and PLC injury may increase their risk.


Assuntos
Cifose , Lordose , Fraturas por Osteoporose , Fusão Vertebral , Idoso , Humanos , Cifose/complicações , Cifose/cirurgia , Lordose/cirurgia , Vértebras Lombares/cirurgia , Fraturas por Osteoporose/etiologia , Fraturas por Osteoporose/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Fatores de Risco , Fusão Vertebral/efeitos adversos , Vértebras Torácicas/cirurgia
8.
Macromol Rapid Commun ; 42(3): e2000458, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33230871

RESUMO

Conventional carbon fiber reinforced thermosetting polymers (CFRPs) are neither recyclable nor repairable due to their crosslinked network. The rapid growing CFRP market raises a serious concern of the waste management. In this work, a viable method to develop a readily recyclable CFRP based on epoxy vitrimer is introduced. First, a self-catalytic epoxy prepolymer with built-in hydroxy and tertiary amine groups is designed, which upon reaction with an anhydride formed a catalyst-free epoxy vitrimer. The epoxy prepolymer is synthesized from a diamine and an excess of bisphenol A epoxy resin. The hydroxyls and tertiary amines of the epoxy prepolymer efficiently catalyze both curing and the dynamic transesterification of the crosslinked polymer without the need of a catalyst. Then, the epoxy vitrimer is used as the matrix resin to prepare CFRP. The resulting CFRP exhibited a tensile strength as high as 356 MPa. More interestingly, the matrix of the CFRP is efficiently degraded in pure water at above 160 °C. This is because the built-in tertiary amines catalyze the hydrolysis of the ester bonds of the crosslinked network. The simple method developed in this work provides a framework for the development of recyclable CFRP.


Assuntos
Resinas Epóxi , Água , Anidridos , Fibra de Carbono , Polímeros
9.
Eur Spine J ; 30(2): 524-533, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32876731

RESUMO

OBJECTIVE: To propose a novel classification and scoring system called the posterior ligament-bone injury classification and severity score (PLICS) that offers a quantitative score to guide the need for posterior stabilization in addition to anterior reconstruction for subaxial cervical fracture dislocations (SCFDs). METHODS: A total of 456 patients with SCFDs were prospectively included. Patients with PLICS ≥ 7 together with extremely unstable lateral mass fracture (EULMF) were classified as high-risk group, and the other patients were classified as low-risk group. For patients in the low-risk group, anterior-only reconstruction was performed; for patients in the high-risk group, additional posterior lateral mass fixation and fusion was performed after anterior reconstruction. Clinical outcome evaluation included using the visual analogue score (VAS), the Neck Disability Index (NDI), and the American Spinal Injury Association (ASIA) impairment scale. The change in the local sagittal alignment kyphosis Cobb angle was also recorded. RESULTS: A total of 370 patients (81.1%) completed the minimal 12-month follow-ups, including 321 patients of low-risk group and 49 patients of high-risk group. Compared with the average VAS score preoperatively, the score at 12-month follow-up was significantly improved (from 6.1 + 0.3 to 1.1 + 0.2 in the low-risk group, P < 0.001; from 6.4 + 0.2 to 1.4 + 0.2 in the high-risk group, P < 0.001). The average NDI score at the 12-month follow-up was statistically low in the low-risk group (8.8 + 2.5 vs 13.8 + 3.4, P = 0.034). At least more than one grade improvement in the ASIA scale was observed in 80.5% of all patients. The local kyphosis Cobb angle at the injured segment averaged improved in both groups. CONCLUSION: A PLICS score ≥ 7 together with EULMF can be the threshold for posterior stabilization in addition to anterior reconstruction for the patients with SCFDs.


Assuntos
Fratura-Luxação , Fraturas da Coluna Vertebral , Fusão Vertebral , Algoritmos , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/lesões , Vértebras Cervicais/cirurgia , Fixação Interna de Fraturas , Humanos , Ligamentos , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento
10.
Int Orthop ; 45(6): 1531-1538, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32989559

RESUMO

BACKGROUND: The accuracy of robot-assisted pedicle screw implantation is a safe and effective method in lumbar surgery, but it still remains controversial in lumbar revision surgery. This study evaluated the clinical safety and accuracy of robot-assisted versus freehand pedicle screw implantation in lumbar revision surgery. METHODS: This was a retrospective study. From January 2018 to December 2019, 81 patients underwent posterior lumbar revision surgery in our hospital. Among them, 39 patients underwent revision surgery performed with robot-assisted pedicle screw implantation (Renaissance robotic system), whereas the remaining 42 patients underwent traditional freehand pedicle screw implantation. All patients underwent magnetic resonance imaging (MRI), computed tomography (CT), and X-ray before revision surgery. The sex, age, body mass index, bone mineral density, operative time, blood loss, operative segments, intra-operative fluoroscopy time, and complications were compared between the two groups. The accuracy of pedicle screw implantation was measured on CT scans based on Gertzbein Robbins grading, and the invasion of superior level facet joint was evaluated by Babu's method. RESULTS: There was no statistical difference about the baseline between the two groups (P > 0.05). Although there were no significant differences in operative time and complications between the two groups (P > 0.05), the robot-assisted group had significantly less intra-operative blood loss and shorter intra-operative fluoroscopy times than the freehand group (P < 0.05). In the robot-assisted group, a total of 267 screws were inserted, which were marked as grade A in 250, grade B in 13, grade C in four, and no grade D or E in any screw. In terms of invasion of superior level facet joint, a total of 78 screws were inserted in the robot-assisted group, which were marked as grade 0 in 73, grade 1 in four, grade 2 in one, and grade 3 in zero. By comparison, 288 screws were placed in total in the freehand group, which were rated as grade A in 251, grade B in 28, grade C in eight, grade D in one, and no grade E in any screw. A total of 82 superior level facet joint screws were inserted in freehand group, which were marked as grade 0 in 62, grade one in 18, grade 2 in two, and grade 3 in zero. The robot-assisted technique was statistically superior to the freehand method in the accuracy of screw placement (P < 0.05). CONCLUSION: Compared with freehand screw implantation, in lumbar revision surgery, the Renaissance robot had higher accuracy and safety of pedicle screw implantation, fewer superior level facet joint violations, and less intra-operative blood loss and intra-operative fluoroscopy time.


Assuntos
Parafusos Pediculares , Procedimentos Cirúrgicos Robóticos , Robótica , Fusão Vertebral , Cirurgia Assistida por Computador , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Reoperação , Estudos Retrospectivos , Procedimentos Cirúrgicos Robóticos/efeitos adversos
11.
Soft Matter ; 16(7): 1760-1770, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31859322

RESUMO

Photo-initiated thiol-ene click chemistry is used to develop shape memory liquid crystalline networks (LCNs). A biphenyl-based di-vinyl monomer is synthesized and cured with a di-thiol chain extender and a tetra-thiol crosslinker using UV light. The effects of photo-initiator concentration and UV light intensity on the curing behavior and liquid crystalline (LC) properties of the LCNs are investigated. The chemical composition is found to significantly influence the microstructure and the related thermomechanical properties of the LCNs. The structure-property relationship is further explored using molecular dynamics simulations, revealing that the introduction of the chain extender promotes the formation of an ordered smectic LC phase instead of agglomerated structures. The concentration of the chain extender affects the liquid crystallinity of the LCNs, resulting in distinct thermomechanical and shape memory properties. This class of LCNs exhibits fast curing rates, high conversion levels, and tailorable liquid crystallinity, making it a promising material system for advanced manufacturing, where complex and highly ordered structures can be produced with fast reaction kinetics and low energy consumption.

12.
BMC Musculoskelet Disord ; 21(1): 423, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32615953

RESUMO

BACKGROUND: This study aimed to compare the clinical outcomes and complications between laminectomy and fusion (LF) and laminoplasty (LP) for multi-level cervical spondylotic myelopathy (MCSM) with increased signal intensity (ISI) on T2-weighted images (T2WI). METHODS: In this retrospective cohort study, we analyzed 52 patients with MCSM with ISI on T2WI who underwent laminoplasty (LP group). The Japanese Orthopedic Association (JOA) score, the Visual Analogue Scale (VAS) score, the physical and mental component scores (PCS and MCS) of Short-Form 36 (SF-36), and the extension and flexion ranges of motion (ROMs) were recorded. As controls, propensity score matching identified 52 patients who underwent laminectomy and fusion (LF group) from January 2014 to June 2016 using 7 independent variables (preoperation): age, sex, JOA score, SF-36 PCS, SF-36 MCS, preoperative symptom duration and high signal intensity ratio (HSIR). RESULTS: The operative duration in the LF group was significantly higher than that in the LP group. At the last follow-up, the JOA score, VAS score, and SF-36 (PCS and MCS) scores were all significantly improved in both groups. The extension and flexion ROMs were decreased in both groups but significantly better in the LP group than in the LF group. Both groups demonstrated similar clinical improvements at the final follow-up. The complication rate was higher in the LF group. CONCLUSION: The present study demonstrates that LP for MCSM with ISI on T2WI achieves similar clinical improvement as LF. However, longer operative durations, higher complication rates and lower extension and flexion ROMs were found in the LF group.


Assuntos
Vértebras Cervicais/cirurgia , Laminectomia/métodos , Laminoplastia/métodos , Doenças da Medula Espinal/cirurgia , Fusão Vertebral/métodos , Idoso , Vértebras Cervicais/diagnóstico por imagem , China , Feminino , Humanos , Laminectomia/efeitos adversos , Laminoplastia/efeitos adversos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Medição da Dor , Complicações Pós-Operatórias , Amplitude de Movimento Articular , Estudos Retrospectivos , Índice de Gravidade de Doença , Doenças da Medula Espinal/diagnóstico por imagem , Fusão Vertebral/efeitos adversos , Resultado do Tratamento
13.
Org Biomol Chem ; 17(37): 8589-8600, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31517383

RESUMO

Herein, a cascade [3 + 2] annulation of N-aryloxyacetamides with 3-(hetero)arylpropiolic acids affording benzofuran-2(3H)-ones via rhodium(iii)-catalyzed redox-neutral C-H functionalization/isomerization/lactonization using an internal oxidative directing group O-NHAc was achieved. This catalytic system provides a regio- and stereoselective approach to synthesize (Z)-3-(amino(aryl)methylene)benzofuran-2(3H)-ones with exclusive Z configuration selectivity, acceptable yields and good functional group tolerance. Preliminary investigations on ultraviolet-visible and fluorescence behaviors reveal that the annulation products may be applied as a promising fluorescent probe for sensing metal cations, especially for cerium (Ce3+).

14.
Macromol Rapid Commun ; 40(7): e1800889, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30721569

RESUMO

Epoxy vitrimers prepared from anhydride-cured epoxies exhibit, repairable and reprocessable properties; however, they generally rely on a large amount of catalyst for accelerating the dynamic transesterification (DTER). If the catalyst loading is not enough, the vitrimer properties will be limited. In this work, a preparation method of catalyst-free epoxy vitrimer is demonstrated by adding glycerol to an epoxy-anhydride curing system. The hydroxyls of glycerol first react with the anhydride to induce the ring-opening of anhydride and form a carboxylic acid, and the latter attacks the epoxy and form a ß-hydroxyester linkage, so the curing can be performed in the absence of catalyst. A significant amount of hydroxy groups are preserved in the crosslinked network, and they serve as both reacting moiety and catalyst for the DTER, which imparts fast relaxation and satisfactory repairability to the materials. By taking advantage of this mechanism, a catalyst-free and self-healing coating is demonstrated. These findings provide a solution to avoid using catalyst in vitrimer preparation and advance the application of vitrimer in coating. However, the addition of glycerol produces a decrease of the T g of the final materials, which needs to be further addressed in the future study.


Assuntos
Anidridos/química , Compostos de Epóxi/química , Glicerol/química , Estrutura Molecular
15.
Med Sci Monit ; 25: 2479-2487, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30946733

RESUMO

BACKGROUND With the in-depth development of minimally invasive spine surgery in recent years, robot- and computer-assisted technologies have been increasingly used and successfully applied to spinal surgery. MATERIAL AND METHODS We performed a retrospective analysis of 60 patients with grade I or II lumbar spondylolisthesis who underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) from January 2017 to December 2017. A robot-assisted surgical system was used in 30 patients for pedicle screw placement. The other 30 patients underwent fluoroscopy-guided percutaneous pedicle screw placement. RESULTS There were 130 screws placed under fluoroscopic guidance, with 26.2% penetration of the pedicle wall. There were 130 screws placed in robotic-assisted surgery, with 6.2% penetration of the pedicle wall. Severe screw deviation (Neo grade III) was identified in 4 screws in the fluoroscopy-guided group, while no severe deviation was noted in the robot-assisted group. In the fluoroscopic group, 15.6% of screws penetrated the superior articular process, and 2.1% screws had severe complications (Babu grade III). However, only 5.1% of screws in the robot-assisted group had severe complications. The mean screw insertion angle was significantly greater in the robot-assisted group than in the fluoroscopy-guided group (23.8±6.1° vs. 18.4±7.2°, P=0.017). CONCLUSIONS Compared to fluoroscopy-guided percutaneous pedicle screw placement, robot-assisted percutaneous pedicle screw placement has the following advantages: greater accuracy, lower incidences of screw penetration of the pedicle wall and invasion of the facet joints, and better screw insertion angle. Combined with MIS-TLIF, robot-assisted percutaneous pedicle screw placement is an effective minimally invasive treatment for lumbar spondylolisthesis.


Assuntos
Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Espondilolistese/cirurgia , Adulto , Idoso , China , Estudos de Coortes , Feminino , Humanos , Região Lombossacral/cirurgia , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Parafusos Pediculares , Estudos Retrospectivos , Robótica , Fusão Vertebral/métodos , Cirurgia Assistida por Computador/métodos , Resultado do Tratamento
16.
Clin Rehabil ; 33(1): 54-63, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30064268

RESUMO

OBJECTIVE:: This study evaluated the possible effect of the combined intervention of physical exercise and cognitive training on cognitive function in stroke survivals with vascular cognitive impairment. DESIGN:: A single-blind (investigator-blinded but not subject-blinded) randomized controlled trial. SETTING:: Medical Rehabilitation Center of Shanghai General Hospital, China. SUBJECTS:: A total of 225 patients (mean age 64.59 years, SD = 4.27) who exhibited vascular cognitive impairment were included in this study. INTERVENTIONS:: Patients were randomly allocated into one of the four groups: (1) physical exercise ( n = 56; 50-minute session), (2) cognitive training ( n = 57; 60-minute session), (3) combined intervention of physical exercise and cognitive training ( n = 55; 50-minute session + 60-minute session), or (4) control groups ( n = 57; 45-minute session). All participants received training for 36 sessions, three days per week, for 12 weeks. PRIMARY MEASURES:: Measures were recorded at baseline, after the intervention and at a six-month follow-up. Primary measurements included the Trail Making Part B, Stroop, forward digit span, and mental rotation tests. RESULTS:: A total of 179 participants (79.56% response rate) completed the study. Cognitive performances on all four tasks in the combined training group improved significantly after the intervention ( P < 0.01). Changes in cognitive performance were greater in the combined intervention group than those in the physical exercise group (e.g. forward digit span, 13.61% vs. 2.18%, P = 0.003), the cognitive training group (e.g. mental rotation, 17.36% vs. 0.87%, P = 0.002), and the control group (e.g. Stroop, -4.11% vs. -0.72%, P = 0.026). CONCLUSION:: The combined intervention produced greater benefits on cognitive function compared to either training alone in stroke survivors with vascular cognitive impairment.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Disfunção Cognitiva/reabilitação , Terapia por Exercício/métodos , Acidente Vascular Cerebral/psicologia , Idoso , China , Cognição/fisiologia , Transtornos Cognitivos , Disfunção Cognitiva/etiologia , Exercício Físico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Método Simples-Cego
17.
BMC Surg ; 19(1): 96, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31337382

RESUMO

BACKGROUND: Occipital neuralgia is one of the postoperative complications of C1 lateral mass screw insertion, which was deemed to be related with the C2 nerve root dysfunction. CASE PRESENTATION: A 52-year-old female patient presented with gradually progressive numbness and weakness in her extremities for 6 months. X-ray and computed tomography (CT) scan revealed obvious anterior atlantoaxial dislocation (ADD), which was reducible on extensive view. Atlantoaxial pedicle screw fixation and bone graft was performed. Immediately after the operation, the neurological symptom significantly improved. The patient complained of restricted cervical rotation and suboccipital neuralgia which was exacerbated by rotation with an intensity of 7 on a visual analog scale (VAS) ranging from 0 to 10 at postoperative day 5. While a satisfactory reduction was detected in the postoperative CT, violation of the left atlantooccipital joint was observed in the left C1 screw. Nimesulide (daily dosage of 0.2 g) and bracing were recommended immediately. At the 2 month follow-up, both the neurological improvement and reduction were maintained. The VAS of suboccipital neuralgia is 3 and decreased to 1 at 6 months postoperative. Bony fusion of the left atlantooccipital joint was confirmed by CT scan at 6 months postoperative. The patient complained that the suboccipital neuralgia was tolerable without the assistance of braces or medications for pain. At the 18 month follow-up, only stiffness of head flexion and rotation was observed without suboccipital neuralgia. CONCLUSION: Suboccipital neuralgia after atlantooccipital joint violation of C1 pedicle screw placement most likely results from C1 nerve root irritation. As the corresponding dermatome differs from the distributing region and aggravated factor of C2 nerve root dysfunction, neuralgia due to C1 irritation was only localized at suboccipital region and exacerbated by rotation.


Assuntos
Articulação Atlantoaxial/cirurgia , Articulação Atlantoccipital , Neuralgia/etiologia , Parafusos Pediculares/efeitos adversos , Complicações Pós-Operatórias/etiologia , Fusão Vertebral/instrumentação , Transplante Ósseo/efeitos adversos , Feminino , Humanos , Instabilidade Articular/cirurgia , Pessoa de Meia-Idade , Neuralgia/diagnóstico por imagem , Complicações Pós-Operatórias/diagnóstico por imagem , Fusão Vertebral/efeitos adversos , Tomografia Computadorizada por Raios X , Resultado do Tratamento
19.
Phys Chem Chem Phys ; 18(6): 4295-9, 2016 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-26804709

RESUMO

The strong fluorescence, in both the solution and the bulk state, of a chromophore-free aliphatic hyperbranched polyether which does not contain N and P atoms was reported for the first time. Effects of concentration and solvent solubility were measured. Its ethanol solution shows a strong blue-green fluorescence (Yu = 0.11-0.39), and its fluorescence shows a strong selective quenching with respect to Fe(3+).

20.
Eur Spine J ; 24(4): 694-701, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25563198

RESUMO

PURPOSE: Several techniques have been introduced to manage irreducible atlantoaxial dislocation (IAAD). However, no study has reported the surgical method for the management of IAAD caused by odontoid fracture malunion. This study aimed to introduce a surgical method of transoral anterior release, odontoid partial resection, and reduction with sequential posterior fusion for the treatment of IAAD caused by odontoid fracture malunion. We also evaluated the clinical efficacy of this surgery. METHODS: This study included seven cases of IAAD caused by odontoid fracture malunion, collected from January 2008 to January 2011. Anterior atlantoaxial release was performed through anterior transoral approach, followed by partial resection of the odontoid process. C1-C2 were then fixed through pedicle screws and rods, and then fused posteriorly by single stage. Neurologic status was evaluated using the Japanese Orthopaedic Association (JOA) scoring system. RESULTS: All seven patients had complete release, and satisfactory reduction. Bony fusion was seen in all patients postoperatively. The patients were followed up for an average of 19.6 months (ranged from 9 to 36 months). The average of patients JOA scores at the final follow-up was significantly higher than that of their preoperative scores. Furthermore, the average improvement in neurological function was 87.4 %. No screw loosening, implant migration or implant failures, atlantoaxial redislocation, or signs of instability were observed in any of the patients during the follow-up period. CONCLUSIONS: Transoral anterior release, odontoid partial resection, and reduction combined with posterior fusion are effective, reliable, and safe procedures for the treatment of IAAD caused by odontoid fracture malunion.


Assuntos
Articulação Atlantoaxial/cirurgia , Fraturas Mal-Unidas/complicações , Luxações Articulares/cirurgia , Processo Odontoide/cirurgia , Fusão Vertebral/métodos , Adulto , Articulação Atlantoaxial/diagnóstico por imagem , Articulação Atlantoaxial/lesões , Parafusos Ósseos , Vértebras Cervicais/cirurgia , Descompressão Cirúrgica/métodos , Feminino , Fraturas Mal-Unidas/diagnóstico por imagem , Fraturas Mal-Unidas/cirurgia , Humanos , Fixadores Internos , Luxações Articulares/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Processo Odontoide/diagnóstico por imagem , Processo Odontoide/lesões , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Adulto Jovem
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