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Organometallic molecules are promising for molecular electronic devices due to their potential to improve electrical conductance through access to complex orbital covalency that is not available to light-element organic molecules. However, studies of the formation of organometallic monolayers and their charge transport properties are scarce. Here, we report the cluster formation and charge transport properties of gold-triarylbismuthane-gold molecular junctions. We found that triarylbismuthane molecules with -CN anchoring groups form clusters during the creation of self-assembled submonolayers. This clustering is attributed to strong interactions between the bismuth (Bi) center and the nitrogen atom in the -CN group of adjacent molecules. Examination of the influence of -NH2 and -CN anchoring groups on junction conductance revealed that, despite a stronger binding energy between the -NH2 group and gold, the conductance per molecular unit (i.e., molecule for the -NH2 group and cluster for the -CN group) is higher with the -CN anchoring group. Further analysis showed that an increase in the number of -CN groups from one to three within the junctions leads to a decrease in conductance while increasing the size of the cluster. This demonstrates the significant effects of different anchoring groups and the impact of varying the number of -CN groups on both the charge transport and cluster formation. This study highlights the importance of selecting the appropriate anchoring group in the design of molecular junctions. Additionally, controlling the size and formation of clusters can be a strategic approach to engineering charge transport in molecular junctions.
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BACKGROUND: The use of subtalar arthroereisis as an adjunct to the surgical treatment of stage 1 flexible progressive collapsing foot deformity (PCFD) is controversial. The aim was to investigate the clinical outcomes and report the implant removal rate of subtalar arthroereisis as an adjunct for stage 1 PCFD. METHODS: A retrospective study of 212 consecutive feet undergoing operative management of stage 1 PCFD with adjunctive subtalar arthroereisis between October 2010 and April 2018. The primary outcome was the Foot and Ankle Outcome Score (FAOS). Secondary outcomes included Foot and Ankle Disability Index (FADI), Euroqol-5D-5L Index and implant removal rate. RESULTS: Post-operative clinical FAOS outcomes were collected for 153 feet (72.2%). At mean 2.5-year follow-up, the mean ± standard deviation FAOS for each domain was as follows; Pain: 81.5 ± 18.5, Symptoms: 79.5 ± 12.9, Activities of Daily Living: 82.5 ± 15.4 and Quality of Life: 64.2 ± 23.7. EQ-5D-5L Index was 0.884 ± 0.152. Pre-operative scores were available for 20 of these feet demonstrating a statistically significant improvement in all FAOS, FADI and EQ-5D-5L domains (p < 0.05). The implant removal rate for persistent sinus tarsi pain was 48.1% (n = 102). CONCLUSION: Use of a subtalar arthroereisis implant as an adjunct to conventional procedures in stage 1 flexible PCFD can result in significant improvement in pain and function. Patients should be counselled as to the relatively frequent rate of subsequent implant removal. LEVEL OF EVIDENCE: IV.
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Two hypervalent trifluoromethyl organobismuth complexes were prepared from commercially available chiral amines, (R)-1-cyclohexylethylamine and (1R, 2R, 3R, 5S)-(-)-isopinocampheylamine; however, only the complex from the latter amine was prepared as a single stereoisomer. Both organobismuth complexes were fully characterized by NMR spectroscopy and single-crystal X-ray crystallography, revealing that the structures were similar to previously reported complexes with a hypervalent Bi-N bond. The complexes were catalytically active in olefin difluorocarbenation with Ruppert-Prakash reagent (TMS-CF3 ) used as a terminal source of CF2 . The catalyst derived from isopinocampheylamine was screened with three prochiral olefins of various reactivity in DCM and toluene. All reactions afforded the 1,1-difluorocyclopropanes in good yields, but no enantiomeric excess was observed.
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BACKGROUND: Recent large studies of third-generation minimally invasive hallux valgus surgery (MIS) have demonstrated significant improvement in clinical and radiologic outcomes. It remains unknown whether these clinical and radiologic outcomes are maintained in the medium to long term. The aim of this study was to investigate the minimum 5-year clinical and radiologic outcomes following third-generation MIS hallux valgus surgery in the hands of a high-volume MIS surgeon. METHODS: A retrospective observational single highly experienced MIS surgeon case series of consecutive patients undergoing primary isolated third-generation percutaneous chevron and Akin osteotomies (PECA) for hallux valgus with a minimum 60-month clinical and radiographic follow-up. Primary outcome was radiographic assessment of the hallux valgus angle (HVA) and intermetatarsal angle (IMA) preoperatively, 6 months, and ≥60 months following PECA. Secondary outcomes included the Manchester-Oxford Foot Questionnaire, patient satisfaction, EuroQol-5D visual analog scale and the visual analog scale for pain. RESULTS: Between 2012 and 2014, 126 consecutive feet underwent isolated third-generation PECA, with complete data available for 78 (61.9%) feet. The median follow-up was 65.0 (IQR 64-69; range 60-88) months. There was a significant improvement in radiographic deformity correction; the median IMA improved from 12.0 degrees (interquartile range [IQR]: 10.8-14.2) to 6.0 degrees (IQR: 4.2-7.3) (P < .001), and the median HVA improved from 27.2 degrees (IQR: 20.6-34.4) to 7.2 degrees (IQR: 3.4-11.6). Median MOXFQ Index score at ≥60-month follow-up was 2.3 (IQR: 0.0-7.8). The radiographic recurrence rate (defined as HVA >15 degrees) was 7.7% at final follow-up. The complication rate was 4.8%. CONCLUSION: Radiologic deformity correction for the 78 feet we were able to follow that had third-generation PECA performed by a single highly experienced MIS surgeon was found to be maintained at a mean follow-up of average 66.8 months, with a radiographic recurrence rate of 7.7%. Clinical PROMs and patient satisfaction levels were high and comparable to other third-generation studies with shorter duration of follow-up. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.
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Juanete , Hallux Valgus , Humanos , Estudios de Seguimiento , Hallux Valgus/diagnóstico por imagen , Hallux Valgus/cirugía , Osteotomía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Coronal and sagittal plane deformities of the lesser toes are common yet challenging to treat. Traditional open releases and translational Weil osteotomies can be unpredictable and lead to postoperative stiffness. We present the results of a percutaneous closing wedge extracapsular osteotomy of the proximal phalanx to treat valgus deformity of the second toe. METHODS: Thirty-one patients underwent 40 percutaneous osteotomies at a median age of 58.6±9.4 years. Using a small dorsomedial incision, a percutaneous proximal metaphyseal medial closing-wedge extracapsular osteotomy of the second toe is performed, leaving the dorsolateral cortex intact. An irrigated low-speed, high-torque 2- × 8-mm burr is used under image guidance. The osteotomy is then closed to correct deformity and taped for 2 weeks. Patient-reported outcomes and weightbearing radiographs were obtained. RESULTS: Questionnaire data was available for 89.7% (n=35) of cases. Most cases (91.4%) were either satisfied or extremely satisfied with the procedure. Radiographs were available for 90.0% of osteotomies, with a median length from surgery to radiographic follow-up of 1.6 years (range 0.5-6.3; SD ±1.5). Median second-toe valgus angle (STVA) decreased from 16.2±10.7 degrees to 5.0±7.0 degrees (P < .001) at final follow-up. All osteotomies united with no delayed union. There were no wound complications or infections. We found 2 cases of radiographic recurrence. CONCLUSION: Percutaneous proximal phalanx base metaphyseal closing wedge extracapsular osteotomies of lesser toes to correct coronal plane deformity is useful adjunct to first-ray corrective surgery and is associated with high levels of patient satisfaction. LEVEL OF EVIDENCE: Level IV, retrospective case series.
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Hallux Valgus , Anciano , Hallux Valgus/cirugía , Humanos , Persona de Mediana Edad , Osteotomía/métodos , Radiografía , Estudios Retrospectivos , Dedos del Pie , Resultado del TratamientoRESUMEN
BACKGROUND: Patients with severe hallux valgus deformity present technical and operative challenges with high rates of recurrence and residual deformity. The clinical and radiologic outcomes of percutaneous surgery for severe hallux valgus are not known. METHODS: A retrospective review of consecutive patients with a hallux valgus angle (HVA) >40 degrees or intermetatarsal angle (IMA) >20 degrees who underwent third-generation percutaneous chevron and Akin osteotomy (PECA) for hallux valgus deformity correction. RESULTS: Between December 2012 and August 2019, 59 feet in 50 patients underwent PECA. Preoperative and follow-up radiographic data were available for 53 feet (89.8%). Postoperative clinical patient-reported outcome measures and satisfaction results were available for 51 feet (86.4%). The mean clinical and radiographic follow-up was 3.1 years and the mean postoperative Manchester-Oxford Foot Questionnaire Index score was 15.1. There was a statistically significant improvement (P < .001) in both IMA and HVA following surgery (IMA 17.5-5.1 degrees; HVA 44.1-11.5 degrees). All patients reported they were satisfied with their outcome, with 76.8% reporting they were highly satisfied. The hallux valgus recurrence rate was 7.5%. CONCLUSION: Percutaneous surgery for severe hallux valgus deformity can achieve a large deformity correction, patient satisfaction, and quality of life, with reasonable rates of residual deformity and low rates of recurrence. LEVEL OF EVIDENCE: Level IV, case series.
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Hallux Valgus , Huesos Metatarsianos , Estudios de Seguimiento , Hallux Valgus/diagnóstico por imagen , Hallux Valgus/cirugía , Humanos , Huesos Metatarsianos/diagnóstico por imagen , Huesos Metatarsianos/cirugía , Osteotomía , Calidad de Vida , Radiografía , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
We model the nonlinear response of a lubricated contact composed of a two-dimensional lipid membrane immersed in a simple fluid between two parallel flat and porous walls under shear. The nonlinear dynamics of the membrane gives rise to a rich dynamical behavior depending on the shear velocity. In quiescent conditions (i.e., absence of shear), the membrane freezes into a disordered labyrinthine wrinkle pattern. We determine the wavelength of this pattern as a function of the excess area of the membrane for a fairly general form of the confinement potential using a sine-profile ansatz for the wrinkles. In the presence of shear, we find four different regimes depending on the shear rate. Regime I. For small shear, the labyrinthine pattern is still frozen, but exhibits a small drift which is mainly along the shear direction. In this regime, the tangential forces on the walls due to the presence of the membrane increase linearly with the shear rate. Regime II. When the shear rate is increased above a critical value, the membrane rearranges, and wrinkles start to align along the shear direction. This regime is accompanied by a sharp drop of the tangential forces on the wall. The membrane usually reaches a steady-state configuration drifting with a small constant velocity at long times. However, we also rarely observe oscillatory dynamics in this regime. Regime III. For larger shear rates, the wrinkles align strongly along the shear direction, with a set of dislocation defects which assemble in pairs. The tangential forces are then controlled by the number of dislocations, and by the number of wrinkles between the two dislocations within each dislocation pairs. In this dislocation-dominated regime, the tangential forces in the transverse direction most often exceed those in the shear direction. Regime IV. For even larger shear, the membrane organizes into a perfect array of parallel stripes with no defects. The wavelength of the wrinkles is still identical to the wavelength in the absence of shear. In this final regime, the tangential forces due to the membrane vanish. These behaviors give rise to a non-linear rheological behavior of lubricated contacts containing membranes.
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BACKGROUND: There are many options for incision closure in forefoot surgery. The aim of this study was to compare topical skin adhesive (2-octyl-cyanoacrylate) to simple interrupted nylon sutures. METHODS: A prospective randomized controlled trial comparing topical skin adhesive (TSA) and nylon sutures (NSs) for elective open forefoot surgery. Primary outcome was Hollander Wound Evaluation Scale (HWES) assessed 2 weeks following surgery. Secondary objectives included time taken for wound closure, wound assessment, patient satisfaction with wound cosmesis, incision pain, and infection rate. RESULTS: Between January and December 2018, 84 feet (70 patients) underwent hallux valgus scarf/Akin osteotomy or first metatarsophalangeal arthrodesis and were randomized to receive either intervention (topical skin adhesive) or control (3/0 nylon sutures). We found worse HWES scores when using TSA compared to NSs (1.07 vs 0.60). Incision closure time was slower for TSA (mean, 272 vs 229 seconds). At 2 weeks postoperatively, wound care was faster for TSA (mean 71 secs) vs NSs (mean 120), and patient-reported pain was less with TSA (visual analog scale: TSA 1.2 vs NSs 2.1). A high degree of overall patient satisfaction was reported in both groups, without significant difference. CONCLUSION: Closure of elective forefoot surgery incisions with topical skin adhesive or interrupted nylon sutures offers high satisfaction rates, low pain scores, and low complications. However, topical skin adhesive was associated with more inflammation and areas of wound separation compared to nylon sutures. We recommend the use of sutures for wound closure in forefoot surgery. LEVEL OF EVIDENCE: Level I, randomized controlled trial.
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Nylons , Adhesivos Tisulares , Adhesivos , Humanos , Estudios Prospectivos , Técnicas de Sutura , Suturas , Cicatrización de HeridasRESUMEN
Gap-filling eddy covariance flux data using quantitative approaches has increased over the past decade. Numerous methods have been proposed previously, including look-up table approaches, parametric methods, process-based models, and machine learning. Particularly, the REddyProc package from the Max Planck Institute for Biogeochemistry and ONEFlux package from AmeriFlux have been widely used in many studies. However, there is no consensus regarding the optimal model and feature selection method that could be used for predicting different flux targets (Net Ecosystem Exchange, NEE; or Evapotranspiration -ET), due to the limited systematic comparative research based on the identical site-data. Here, we compared NEE and ET gap-filling/prediction performance of the least-square-based linear model, artificial neural network, random forest (RF), and support vector machine (SVM) using data obtained from four major row-crop and forage agroecosystems located in the subtropical or the climate-transition zones in the US. Additionally, we tested the impacts of different training-testing data partitioning settings, including a 10-fold time-series sequential (10FTS), a 10-fold cross validation (CV) routine with single data point (10FCV), daily (10FCVD), weekly (10FCVW) and monthly (10FCVM) gap length, and a 7/14-day flanking window (FW) approach; and implemented a novel Sliced Inverse Regression-based Recursive Feature Elimination algorithm (SIRRFE). We benchmarked the model performance against REddyProc and ONEFlux-produced results. Our results indicated that accurate NEE and ET prediction models could be systematically constructed using SVM/RF and only a few top informative features. The gap-filling performance of ONEFlux is generally satisfactory (R2 = 0.39-0.71), but results from REddyProc could be very limited or even unreliable in many cases (R2 = 0.01-0.67). Overall, SIRRFE-refined SVM models yielded excellent results for predicting NEE (R2 = 0.46-0.92) and ET (R2 = 0.74-0.91). Finally, the performance of various models was greatly affected by the types of ecosystem, predicting targets, and training algorithms; but was insensitive towards training-testing partitioning. Our research provided more insights into constructing novel gap-filling models and understanding the underlying drivers affecting boundary layer carbon/water fluxes on an ecosystem level.
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Cell crawling on two-dimensional surfaces is a relatively well-understood phenomenon that is based on actin polymerization at a cell's front edge and anchoring on a substrate, allowing the cell to pull itself forward. However, some cells, such as cancer cells invading a three-dimensional matrigel, can also swim in the bulk, where surface adhesion is impossible. Although there is strong evidence that the self-organized engine that drives cells forward in the bulk involves myosin, the specific propulsion mechanism remains largely unclear. Here, we propose a minimal model for in-bulk self-motility of a droplet containing an isotropic and compressible contractile gel, representing a cell extract containing a disordered actomyosin network. In our model, contraction mediates a feedback loop between myosin-induced flow and advection-induced myosin accumulation, which leads to clustering and locally enhanced flow. The symmetry of such flow is then spontaneously broken through actomyosin-membrane interactions, leading to self-organized droplet motility relative to the underlying solvent. Depending on the balance between contraction, diffusion, detachment rate of myosin, and effective surface tension, this motion can be either straight or circular. Our simulations and analytical results shed new light on in-bulk myosin-driven cell motility in living cells and provide a framework to design a novel type of synthetic active matter droplet potentially resembling the motility mechanism of biological cells.
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Citoesqueleto de Actina , Actomiosina , Actinas , Movimiento Celular , Contracción Muscular , MiosinasRESUMEN
BACKGROUND: It is common clinical practice to use either flat or reverse camber shoes to protect the foot for up to 6 weeks after surgery for hallux valgus or hallux rigidus. To date there is a paucity of evidence as to whether there is any difference between these 2 postoperative shoes, in either patient satisfaction or clinical outcomes. METHODS: One hundred consecutive patients undergoing scarf/Akin osteotomies or first metatarsophalangeal joint (MTPJ) arthrodesis were recruited. Patients were randomized 50:50 to either flat or reverse camber postoperative shoes. Patients undergoing ancillary lesser toe procedures were not excluded. Patient satisfaction was assessed by visual analog scale (VAS) pain score and Likert satisfaction survey. Radiographic outcomes were reviewed at 1 year observing differences in fusion rates or deformity recurrence. There were 47 patients in the reverse cam and 43 in the flat shoe group. No difference in primary forefoot operation, additional operation, age at surgery, or preop VAS pain score was seen. RESULTS: At 6 weeks, there was no significant difference in postop VAS pain score. The flat shoe group was significantly more likely to be satisfied with their general mobility (86.0% vs 61.7%; P = .01) and with their stability in the shoe (90.7% vs 69.6%; P = .03). No significant difference was seen between groups for nonunion or hallux valgus recurrence rates. CONCLUSION: Both forms of postoperative footwear were effective in enabling patients to mobilize and in preventing adverse outcomes. Patients were more likely to be satisfied with a flat postoperative shoe due to improved stability and ease of mobilizing. The results of this study aid surgeon decision making for postoperative footwear in forefoot surgery. LEVEL OF EVIDENCE: Level II, prospective randomized controlled trial.
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Hallux Rigidus/cirugía , Hallux Valgus/cirugía , Procedimientos Ortopédicos , Zapatos , Adulto , Anciano , Anciano de 80 o más Años , Diseño de Equipo , Hallux Rigidus/diagnóstico por imagen , Hallux Valgus/diagnóstico por imagen , Humanos , Persona de Mediana Edad , Dimensión del Dolor , Satisfacción del Paciente , Estudios Prospectivos , Radiografía , Encuestas y CuestionariosRESUMEN
We report on the modeling of the dynamics of confined lipid membranes. We derive a thin film model in the lubrication limit which describes an inextensible liquid membrane with bending rigidity confined between two adhesive walls. The resulting equations share similarities with the Swift-Hohenberg model. However, inextensibility is enforced by a time-dependent nonlocal tension. Depending on the excess membrane area available in the system, three different dynamical regimes, denoted as A, B and C, are found from the numerical solution of the model. In regime A, membranes with small excess area form flat adhesion domains and freeze. Such freezing is interpreted by means of an effective model for curvature-driven domain wall motion. The nonlocal membrane tension tends to a negative value corresponding to the linear stability threshold of flat domain walls in the Swift-Hohenberg equation. In regime B, membranes with intermediate excess areas exhibit endless coarsening with coexistence of flat adhesion domains and wrinkle domains. The tension tends to the nonlinear stability threshold of flat domain walls in the Swift-Hohenberg equation. The fraction of the system covered by the wrinkle phase increases linearly with the excess area in regime B. In regime C, membranes with large excess area are completely covered by a frozen labyrinthine pattern of wrinkles. As the excess area is increased, the tension increases and the wavelength of the wrinkles decreases. For large membrane area, there is a crossover to a regime where the extrema of the wrinkles are in contact with the walls. In all regimes after an initial transient, robust localised structures form, leading to an exact conservation of the number of adhesion domains.
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We have modeled the nonlinear dynamics and the rheological behavior of a system under shear containing a membrane confined between two attractive walls. The presence of the membrane induces additional tangential forces on the walls that always increase the global friction. At low shear rates, the membrane exhibits chaotic dynamics with slow coarsening leading to thixotropy, i.e. to a slow decrease of the membrane-induced tangential forces on the walls. At intermediate shear rates, the membrane profile presents stationary periodic patterns. At higher shear rates, membrane dynamics are governed by a nonlinear evolution equation which is similar to the Kuramoto-Sivashinski equation, but with a sixth-order stabilizing term. The membrane experiences chaotic dynamics without coarsening. As a consequence of the nonlinear dynamics of the membrane at intermediate and large shear rates, the system exhibits shear thinning.
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Modification of the classic terpyridine pincer ligand with pendent NHR (R = mesityl) groups provides enhanced activity and stability in Ru-catalyzed dehydrogenation catalysis. These second sphere modifications furnish highly active catalysts for the oxidant-free dehydrogenative oxidation of primary alcohols to carboxylates and facilitate catalyst recycling.
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INTRODUCTION: Femoral impaction bone allografting in revision hip arthroplasty facilitates physiological reconstruction with restoration of bone stock, allowing implantation of a standard cemented femoral component. The purpose of this study was to report our experience in femoral component revision arthroplasty with impaction morsellised cancellous bone allograft using custom impactors and a cemented triple-taper polished stem. METHODS: Retrospective analysis of all cases of femoral component revision hip arthroplasty with impaction bone grafting undertaken by a single surgeon from 2005 to 2011. Outcome measures included radiographic analysis of stem subsidence over time, graft remodelling and incorporation, and clinical progress. RESULTS: We reviewed 47 consecutive hips in 44 patients, mean age 62 years (37-88). Femoral impaction with allograft was performed as either single stage (41 cases) or 2-stage (6 cases) procedures. All patients received a cemented C-stem prosthesis. The mean follow-up period was 5.1 (1.3-9.4) years. The median preoperative bone defect score was 3 (interquartile range [IQR] 2-3) using the Endo-Klinik classification. Radiological evidence of graft incorporation was observed in 89% (281 of 315 zones) with additional remodelling observed in 33% (103 of 315 zones). The median stem subsidence at 1-year follow-up was 1.1 mm (standard deviation [SD] 1.24 mm, range 0-6 mm). The median Oxford Hip Score at the most recent follow-up was 36.5. To date no femoral component has undergone further revision. CONCLUSIONS: Encouraging results have been obtained with this technique for the treatment of significant bone loss in revision hip arthroplasty, allowing implantation of a standard prosthesis.
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Artroplastia de Reemplazo de Cadera/efectos adversos , Trasplante Óseo/métodos , Fémur/cirugía , Prótesis de Cadera/efectos adversos , Osteólisis/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Cementos para Huesos , Femenino , Fémur/diagnóstico por imagen , Estudios de Seguimiento , Articulación de la Cadera , Humanos , Masculino , Persona de Mediana Edad , Osteólisis/etiología , Complicaciones Posoperatorias , Diseño de Prótesis , Falla de Prótesis , Radiografía , Reoperación/métodos , Estudios Retrospectivos , Factores de Tiempo , Trasplante HomólogoRESUMEN
We discuss the nonlinear dynamics and fluctuations of interfaces with bending rigidity under the competing attractions of two walls with arbitrary permeabilities. This system mimics the dynamics of confined membranes. We use a two-dimensional hydrodynamic model, where membranes are effectively one-dimensional objects. In a previous work [T. Le Goff et al., Phys. Rev. E 90, 032114 (2014)], we have shown that this model predicts frozen states caused by bending rigidity-induced oscillatory interactions between kinks (or domain walls). We here demonstrate that in the presence of tension, potential asymmetry, or thermal noise, there is a finite threshold above which frozen states disappear, and perpetual coarsening is restored. Depending on the driving force, the transition to coarsening exhibits different scenarios. First, for membranes under tension, small tensions can only lead to transient coarsening or partial disordering, while above a finite threshold, membrane oscillations disappear and perpetual coarsening is found. Second, potential asymmetry is relevant in the nonconserved case only, i.e., for permeable walls, where it induces a drift force on the kinks, leading to a fast coarsening process via kink-antikink annihilation. However, below some threshold, the drift force can be balanced by the oscillatory interactions between kinks, and frozen adhesion patches can still be observed. Finally, at long times, noise restores coarsening with standard exponents depending on the permeability of the walls. However, the typical time for the appearance of coarsening exhibits an Arrhenius form. As a consequence, a finite noise amplitude is needed in order to observe coarsening in observable time.
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A challenging case of a nonunion of the proximal femur complicated by infection attributed to microbial and fungal pathogens requiring a combination of novel surgical techniques to achieve eradication of infection, preservation of the native hip joint, and restoration of function.
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Antibacterianos/administración & dosificación , Antifúngicos/administración & dosificación , Candidiasis/tratamiento farmacológico , Fijación Intramedular de Fracturas/efectos adversos , Fracturas no Consolidadas/cirugía , Fracturas de Cadera/cirugía , Infecciones Estafilocócicas/tratamiento farmacológico , Infección de Heridas/tratamiento farmacológico , Adulto , Amoxicilina/administración & dosificación , Anfotericina B/administración & dosificación , Cementos para Huesos , Candidiasis/complicaciones , Candidiasis/diagnóstico , Fluconazol/administración & dosificación , Curación de Fractura , Humanos , Masculino , Recuperación de la Función , Infecciones Estafilocócicas/complicaciones , Infecciones Estafilocócicas/diagnóstico , Resultado del Tratamiento , Vancomicina/administración & dosificación , Infección de Heridas/diagnóstico , Infección de Heridas/cirugíaRESUMEN
The adhesion dynamics of a membrane confined between two permeable walls is studied using a two-dimensional hydrodynamic model. The membrane morphology decomposes into adhesion patches on the upper and the lower walls and obeys a nonlinear evolution equation that resembles that of phase-separation dynamics, which is known to lead to coarsening, i.e., to the endless growth of the adhesion patches. However, due to the membrane bending rigidity, the system evolves toward a frozen state without coarsening. This frozen state exhibits an order-disorder transition when increasing the permeability of the walls.
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Membrana Celular/química , Congelación , Hidrodinámica , Dinámicas no Lineales , Membrana Celular/metabolismo , Lubrificación , PermeabilidadRESUMEN
The current available evidence for the use of bone graft substitutes in the management of subchondral bone defects associated with tibial plateau fractures as to their efficiency and safety has been collected following a literature review of the Ovid MEDLINE (1948-Present) and EMBASE (1980-Present). Nineteen studies were analysed reporting on 672 patients (674 fractures), with a mean age of 50.35 years (range 15-89), and a gender ratio of 3/2 males/females. The graft substitutes evaluated in the included studies were calcium phosphate cement, hydroxyapatite granules, calcium sulphate, bioactive glass, tricalcium phosphate, demineralised bone matrix, allografts, and xenograft. Fracture healing was uneventful in over 90% of the cases over a variant period of time. Besides two studies reporting on injectable calcium phosphate cement excellent incorporation was reported within 6 to 36 months post-surgery. No correlation was made by any of the authors between poor incorporation/resorption and adverse functional or radiological outcome. Secondary collapse of the knee joint surface ≥ 2 mm was reported in 8.6% in the biological substitutes (allograft, DBM, and xenograft), 5.4% in the hydroxyapatite, 3.7% in the calcium phosphate cement, and 11.1% in the calcium sulphate cases. The recorded incidence of primary surgical site and donor site infection (3.6%) was not statistically significant different, however donor site-related pain was reported up to 12 months following autologous iliac bone graft (AIBG) harvest. Shorter total operative time, greater tolerance of early weight bearing, improved early functional outcomes within the first year post-surgery was also recorded in the studies reporting on the use of injectable calcium phosphate cement (Norian SRS). Despite a lack of good quality randomised control trials, there is arguably sufficient evidence supporting the use of bone graft substitutes at the clinical setting of depressed plateau fractures.