Condensate interfaces can accelerate protein aggregation.

Protein aggregates, formed from the assembly of aberrant, misfolded proteins, are a hallmark of neurodegenerative diseases. Disease-associated aggregates such as mutant Huntingtin polyQ inclusions, are typically enriched in p62/SQSTM1, an oligomeric protein that binds to and sequesters aberrant proteins. p62 has been suggested to sequester proteins through formation of liquid-like biomolecular condensates, but the physical mechanisms by which p62 condensates may regulate pathological protein aggregation remain unclear. Here, we use a light-inducible biomimetic condensate system to show that p62 condensates enhance coarsening of mutant polyQ aggregates through interface-mediated sequestration, which accelerates polyQ accumulation into larger aggregates. However, the resulting large aggregates accumulate polyubiquitinated proteins, which depletes free p62, ultimately suppressing further p62 condensation. This dynamic interplay between interface-mediated coarsening of solid aggregates and downstream consequences on the phase behavior of associated regulatory proteins could contribute to the onset and progression of protein aggregation diseases.

Size distributions of intracellular condensates reflect competition between coalescence and nucleation.

Phase separation of biomolecules into condensates has emerged as a mechanism for intracellular organization and affects many intracellular processes, including reaction pathways through the clustering of enzymes and pathway intermediates. Precise and rapid spatiotemporal control of reactions by condensates requires tuning of their sizes. However, the physical processes that govern the distribution of condensate sizes remain unclear. Here we show that both native and synthetic condensates display an exponential size distribution, which is captured by Monte Carlo simulations of fast nucleation followed by coalescence. In contrast, pathological aggregates exhibit a power-law size distribution. These distinct behaviours reflect the relative importance of nucleation and coalescence kinetics. We demonstrate this by utilizing a combination of synthetic and native condensates to probe the underlying physical mechanisms determining condensate size. The appearance of exponential distributions for abrupt nucleation versus power-law distributions under continuous nucleation may reflect a general principle that determines condensate size distributions.

Arthroscopic Reduction and Fixation of Coronoid Fractures with Bending K-Wire: A New Technique.

The ulnar coronoid process plays a key role in maintaining elbow stability; however, there is no gold standard treatment for ulnar coronoid process fractures. We present a novel surgical technique, arthroscopic reduction and bent K-wire fixation, for type II and III coronoid process fractures according to the O'Driscoll classification. Five patients were treated and retrospectively reviewed between January 2016 and December 2019. All the surgeries were performed by a single surgeon. We evaluated clinical outcomes by evaluating a range of motion, disability of arm, shoulder, and hand (DASH) score, Mayo Elbow Performance score (MEPS), and radiographic images. Intraoperative and postoperative radiographs showed that the fractures healed well and were satisfactorily fixed. The average elbow extension/flexion was -3/130, with an average DASH score of 2.42 and MEPS of 97. Coronoid process fractures can be treated successfully with arthroscopic reduction and fixation of bent K-wire, which allows more rigid fixation and early functional exercise, resulting in good outcomes without special tools.

Factors Associated with Mechanical Complications in Intertrochanteric Fracture Treated with Proximal Femoral Nail Antirotation.

PURPOSE: Although proximal femoral nail antirotation (PFNA; Synthes, Switzerland) has demonstrated satisfactory results when used for the treatment of intertrochanteric fractures, mechanical complications may occur. To better quantify the risk of mechanical complications when proximal femoral nail antirotation is used to treat intertrochanteric fractures, this study aimed to: (1) characterize the frequency of mechanical complications and extent of blade sliding and their correlation with reduction quality and (2) identify factors associated with mechanical complications. MATERIALS AND METHODS: A review of medical records from 93 patients treated for intertrochanteric fractures with a minimum of 6-months of follow-up between February 2014 and February 2019 was conducted. Blade position was evaluated using Tip-apex distance (TAD) and Cleveland index. The extent of blade sliding was evaluated using the adjusted Doppelt's method for intramedullary nailing. Individuals were classified as having or not having mechanical complications, and reduction quality and radiologic outcomes were compared between the two groups. RESULTS: Mechanical complications occurred in 12 of 94 hips (12.8%), with 11 out of 12 being from the intramedullary reduction group. There was no significant difference in TAD between groups; however, there were significant differences were noted in Cleveland index, AO/OTA classification, reduction quality and extent of blade sliding. The mean blade sliding distance was 1.17 mm (anatomical group), 3.28 mm (extramedullary group), and 6.11 mm (intramedullary group), respectively (P<0.001). Data revealed that blade sliding was an associated factor for mechanical complications (odds ratio 1.25, 95% confidence interval 1.03-1.51). CONCLUSION: The extent of blade sliding determined using the adjusted Doppelt's method was significantly associated with mechanical complications suggesting that prevention of excessive sliding through proper intraoperative reduction is important to help achieve satisfactory treatment outcomes.

Simulation of Design Factors of a Clutch Pack for Power-Shift Transmission for an Agricultural Tractor.

The objective of this study is the simulation of the most affected design factors and variables of the clutch pack for the power-shift transmission (PST) of a tractor based measured data. The simulation model, the mathematical model of sliding velocity, a moment of inertia, and clutch engagement pressure of clutch pack were developed using the powertrain and configurations of the real PST tractor. In this study, the sensor fusion method was used to precisely measure the proportional valve pressure by test bench, which was applied to the simulation model. The clutch engagement times were found 1.20 s at all temperatures for determined factors. The engagement pressures have a significant difference at various temperatures (25 to 100 °C) of the hydraulic oils after the 1.20 s but the most affected factors were satisfied with the simulation conditions that ensure the clutch engagement on time. Finally, this sensor fusion method is believed to be helpful in realizing precision agriculture through minimization of power loss and maximum energy efficiency of tractors.

The impact of sequential therapy from short-term teriparatide to denosumab compared with denosumab alone in patients with osteoporotic hip fracture: a 1-year follow-up study.

BACKGROUND: Sequential therapy from bone-forming medication to resorptive agents is reportedly effective for patients with severe osteoporosis. The objective of this study is to determine the impact of implementing short-term teriparatide (TPTD) intervention before denosumab (DMab) therapy compared with DMab therapy alone for 1 year after hip fracture. METHODS: We retrospectively reviewed the medical records and radiographs of patients who were treated due to osteoporotic hip fracture. TPTD was administered to 22 patients for an average of 12.1 weeks after which the intervention was switched to DMab therapy for 12 months (group 1). DMab alone was administered to 16 patients for 12 months (group 2). Bone mineral density (BMD) was evaluated before and after treatment at the 1-year follow-up. The improvement of BMD in hip and spine was compared with the levels of bone turnover marker. RESULTS: The difference in femoral neck BMD was 0.005 ± 0.04 in group 1 and - 0.014 ± 0.10 in group 2 (p = 0.442). The difference of spine BMD was 0.043 ± 0.05 in group 1 and 0.052 ± 0.06 in group 2 (p = 0.640). BMD of the spine improved significantly in groups 1 and 2 (p < 0.001, p = 0.002). There was no statistical difference in C-terminal telopeptide and osteocalcin level. CONCLUSION: Short-term TPTD administration followed by DMab alone was effective only in improving spine BMD. Short-term treatment with TPTD caused mild improvement in femur neck BMD compared with DMab alone. However, further research with a longer duration of TPTD treatment is warranted, as our findings lack statistical significance.

Causes and treatment outcomes of revision surgery after open reduction and internal fixation of tibial plateau fractures.

PURPOSE: Treatment of a tibial plateau fracture (TPF) remains controversial and is generally challenging. Many authors report good results after conventional open reduction and internal fixation in TPF, but complications still occur. This study analyzed causes and outcomes of revision surgery for TPF. The usefulness of a flow chart for revision surgery in TPF was also evaluated. METHODS: We reviewed all patients who underwent more than two operations for a TPF between 2008 and 2015. Finally, 24 cases were selected and retrospectively investigated. The medial tibial plateau angle and proximal posterior tibial angle were radiologically evaluated. The American Knee Society Score (AKSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), range of motion (ROM), and bone union time were investigated after surgery. RESULTS: Revision surgery for infection was performed in eight cases, for nonunion in six cases, for posttraumatic arthritis (with total knee arthroplasty) in six cases, and for other reasons in four cases. The mean clinical AKSS at final follow-up was 87.3 ± 5.3 (range, 75-95), the functional AKSS was 81.9 ± 5.5 (range, 70-90), the WOMAC score was 9.9 ± 3.1 (range, 5-16), the flexion ROM was 119.8 ± 16.5° (range, 100-150°), and the extension ROM was 2.5 ± 3.3° (range, 0-10°). CONCLUSIONS: Although complications cannot be avoided in some cases, good clinical outcomes are possible when patients are divided according to the presence or absence of infection, with selection of appropriate revision surgery as shown in the flow chart. If an infection is present, treatment should be based on the presence or absence of bone union. If there is no infection, treatment should be based on the presence or absence of nonunion, post-traumatic arthritis, malunion, or immediate post-operative malreduction.

A novel method using bone peg fixation for acute osteochondral fracture of the talus: a surgical technique.

INTRODUCTION: The osteochondral fracture of the talus is an uncommon condition, therefore, there are controversies for the optimal treatment. We report a novel surgical technique of bone peg fixation for osteochondral fracture of the talus. MATERIALS AND METHODS: We report two cases that underwent bone peg fixation for the acute osteochondral fractures of talus. Clinical and radiographic evaluations were performed at the last follow-up. RESULTS: At the last follow-up, mean ROM of ankle joint was 50° (range 45°-55°). Additionally, mean VAS and AOFAS score were 0 and 100 at the last follow-up, respectively. All patients obtained bone union without complication at the last follow-up radiographs. CONCLUSIONS: This case study shows good clinical and radiographic results with autologous bone peg fixation in patients with acute osteochondral fractures of the talus. LEVEL OF EVIDENCE: V, expert opinion.

Gelatin/PVA scaffolds fabricated using a 3D-printing process employed with a low-temperature plate for hard tissue regeneration: Fabrication and characterizations.

Tissue engineering aims to repair or replace damaged tissues or organs using biomedical scaffolds cultured with cells. The scaffolds composed of biomaterials should guide the cells to mature into functional tissues or organs. An ideal scaffold to regenerate hard tissues should have mechanical stability as well as biocompatibilities. It has been well known that gelatin can provide outstanding biological activities, but its low mechanical stability can be one of obstacles to be used in hard tissue regeneration. To overcome the issue, we used PVA, which can reinforce the low mechanical stability of the gelatin. The gelatin/PVA scaffolds have been fabricated using a low temperature 3D-printing process. By manipulating various weight fractions of PVA/gelatin, we can obtain the optimal mixture ratio in aspect of the physical and biological properties of the scaffolds. As a result, a weight fraction of 5:5 showed appropriate mechanical strength and enhanced cell activities, such as cell proliferation and differentiation. The gelatin/PVA scaffold showed potential for future application as biomedical scaffold in soft and hard tissue regeneration.

Computational Design of Functional Amyloid Materials with Cesium Binding, Deposition, and Capture Properties.

Amyloid materials are gaining increasing attention as promising materials for applications in numerous fields. Computational methods have been successfully implemented to investigate the structures of short amyloid-forming peptides, yet their application in the design of functional amyloid materials is still elusive. Here, we developed a computational protocol for the design of functional amyloid materials capable of binding to an ion of interest. We applied the protocol in a test case involving the design of amyloid materials with cesium ion deposition and capture properties. As part of the protocol, we used an optimization-based design model to introduce mutations at non-ß-sheet residue positions of an amyloid designable scaffold. The designed amino acids introduced to the scaffold mimic how amino acids bind to cesium ions according to experimentally resolved structures and also aim at energetically stabilizing the bound conformation of the pockets. The optimum designs were computationally validated using a series of simulations and structural analysis to select the top designed peptides, which are predicted to form fibrils with cesium ion binding properties for experimental testing. Experiments verified the amyloid-forming properties of the selected top designed peptides, as well as the cesium ion deposition and capture properties by the amyloid materials formed. This study demonstrates the first, to the best of our knowledge, computational design protocol to functionalize amyloid materials for ion binding properties and suggests that its further advancement can lead to novel, highly promising functional amyloid materials of the future.

Hierarchical, Self-Healing and Superhydrophobic Zirconium Phosphate Hybrid Membrane Based on the Interfacial Crystal Growth of Lyotropic Two-Dimensional Nanoplatelets.

We demonstrate a facile route to in situ growth of lyotropic zirconium phosphate (ZrP) nanoplates on textiles via an interfacial crystal growing process. The as-prepared hybrid membrane shows a hierarchical architecture of textile fibers (porous platform for fluid transport), ZrP nanoplatelets (layered scaffolds for chemical barriers), and octadecylamine (organic species for superhydrophobic functionalization). Interestingly, such a hybrid membrane is able to separate the oily wastewater with a high separation efficiency of 99.9%, even at in harsh environments. After being chemically etched, the hybrid membrane is able to restore its hydrophobicity autonomously and repeatedly, owing to the hierarchical structure that enables facile loading of healing agent. We anticipate that the concept of implanting superhydrophobic self-healing features in anisotropic structure of lyotropic nanoparticles will open up new opportunities for developing advanced multifunctional materials for wastewater treatment, fuel purification, and oil spill mitigation.

Genome-Wide Expression Profiling of OsWRKY Superfamily Genes during Infection with Xanthomonas oryzae pv. oryzae Using Real-Time PCR.

WRKY transcription factors (TFs) are involved in regulating a range of biological processes such as growth, development, and the responses to biotic and abiotic stresses. Genome-wide expression profiling of OsWRKY TF superfamily genes in rice after infection with Xanthomonas oryzae pv. oryzae (Xoo) was performed to elucidate the function of OsWRKY TFs in the interaction between rice and Xoo. Of the 111 OsWRKY TF genes tested, the transcription of 94 genes changed after Xoo infection. The OsWRKY TF genes were classified into eight types according to their expression profiles. Eighty-two genes in Groups I, II, III, IV, VII were up-regulated after exposure to a compatible or an incompatible race of Xoo. Examination of salicylic acid (SA)-deficient rice lines revealed that SA was involved in Xa1-mediated resistance to Xoo infection. OsWRKY TF genes involved in Xa1-mediated resistance were classified according to their SA-dependent or -independent expression. In SA-deficient rice, the expression of 12 of 57 OsWRKY TF genes involved in Xa1-mediated resistance was compromised. Of these six OsWRKY TF genes were induced by SA. OsWRKY88, an example of a gene possibly involved in SA-dependent Xa1-mediated resistance, activated defense related genes and increased resistance to Xoo. Thus, expression profiling of OsWRKY TF genes may help predict the functions of OsWRKY TF genes involved in Xa1-mediated resistance.

Versatile design of hydrogel-based scaffolds with manipulated pore structure for hard-tissue regeneration.

In recent years, a variety of biomimetic hydrogel scaffolds have been used in tissue engineering because hydrogels can provide reasonable soft-tissue-like environmental conditions for various cell responses. However, although hydrogels can provide an outstanding biofunctional platform, their poor mechanical stability and low processability have been obstacles for their usage as biomedical scaffolds. To overcome this limitation, we propose a simple and versatile method using 3D printing supplemented with a low-temperature working plate and coating process to reinforce the mechanical properties and various cellular activities by accommodating the poly(ε-caprolactone) (PCL). To determine the efficiency of the method, we used two typical hydrogels (alginate and collagen), which were deposited in a multi-layer configuration, and PCL as a coating agent. The scaffolds were evaluated in terms of various physical and cellular activities (metabolic activity and osteogenic activity). Throughout the experiments, significant increases in the tensile modulus (>6-fold), cell proliferation (>1.2-fold), and calcium deposition (>1.3-fold) were observed for the hydrogel/PCL scaffolds compared to those for pure hydrogel. Based on the experimental results, we can confirm that the proposed hydrogel scaffold can be a highly promising biomedical scaffold for application in tissue regeneration.

Mechanically reinforced cell-laden scaffolds formed using alginate-based bioink printed onto the surface of a PCL/alginate mesh structure for regeneration of hard tissue.

Cell-printing technology has provided a new paradigm for biofabrication, with potential to overcome several shortcomings of conventional scaffold-based tissue regeneration strategies via controlled delivery of various cell types in well-defined target regions. Here we describe a cell-printing method to obtain mechanically reinforced multi-layered cell-embedded scaffolds, formed of micron-scale poly(ε-caprolactone) (PCL)/alginate struts coated with alginate-based bioink. To compare the physical and cellular activities, we used a scaffold composed of pure alginate (without cells) coated PCL/alginate struts as a control. We systematically varied the ratio of alginate cross-linking agent, and determined the optimal cell-coating conditions to form the PCL/alginate struts. Following fabrication of the cell (MG63)-laden PCL/alginate scaffold, the bioactivity was evaluated in vitro. The laden cells exhibited a substantially more developed cytoskeleton compared with those on a control scaffold consisting of the same material composition. Based on these results, the printed cells exhibited a significantly more homogenous distribution within the scaffold compared with the control. Cell proliferation was determined via MTT assays at 1, 3, 7, and 14 days of culture, and the proliferation of the cell-printed scaffold was substantially in excess (∼2.4-fold) of that on the control. Furthermore, the osteogenic activity such as ALP was measured, and the cell-laden scaffold exhibited significantly greater activity (∼3.2-fold) compared with the control scaffold.

Dose optimization of breast balloon brachytherapy using a stepping 192Ir HDR source.

There is a considerable underdosage (11%-13%) of PTV due to anisotropy of a stationary source in breast balloon brachytherapy. We improved the PTV coverage by varying multiple dwell positions and weights. We assumed that the diameter of spherical balloons varied from 4.0 cm to 5.0 cm, that the PTV was a 1-cm thick spherical shell over the balloon (reduced by the small portion occupied by the catheter path), and that the number of dwell positions varied from 2 to 13 with 0.25-cm steps, oriented symmetrically with respect to the balloon center. By assuming that the perfect PTV coverage can be achieved by spherical dose distributions from an isotropic source, we developed an optimization program to minimize two objective functions defined as: (1) the number of PTV-voxels having more than 10% difference between optimized doses and spherical doses, and (2) the difference between optimized doses and spherical doses per PTV-voxel. The optimal PTV coverage occurred when applying 8-11 dwell positions with weights determined by the optimization scheme. Since the optimization yields ellipsoidal isodose distributions along the catheter, there is relative skin sparing for cases with source movement approximately tangent to the skin. We also verified the optimization in CT-based treatment planning systems. Our volumetric dose optimization for PTV coverage showed close agreement to linear or multiple-points optimization results from the literature. The optimization scheme provides a simple and practical solution applicable to the clinic.