Digital smart internal fixation surgery for coronal process basal fracture with normal joint spaces or radius-shortening: Occult factor of radius-ulna load sharing.

BACKGROUND: Reasonable postoperative humeroradial and humeroulnar joint spaces maybe an important indicator in biomechanical stability of smart internal fixation surgery for coronoid process basal fractures (CPBF). The aim of this study is to compare elbow articular stresses and elbow-forearm stability under smart internal fixations for the CPBF between normal elbow joint spaces and radius-shortening, and to determine the occult factor of radius-ulna load sharing. METHODS: CT images of 70 volunteers with intact elbow joints were retrospectively collected for accurate three-dimensional reconstruction to measure the longitudinal and transverse joint spaces. Two groups of ten finite element (FE) models were established prospectively between normal joint space and radius-shortening with 2.0 mm, including intact elbow joint and forearm, elbow-forearm with CPBF trauma, anterior or posterior double screws-cancellous bone fixation, mini-plate-cancellous bone fixation. Three sets of physiological loads (compression, valgus, varus) were used for FE intelligent calculation, FE model verification, and biomechanical and motion analysis. RESULTS: The stress distribution between coronoid process and radial head, compression displacements and valgus angles of elbow-forearm in the three smart fixation models of the normal joint spaces were close to those of corresponding intact elbow model, but were significantly different from those of preoperative CPBF models and fixed radius-shortening models. The maximum stresses of three smart fixation instrument models of normal joint spaces were significantly smaller than those of the corresponding fixed radius-shortening models. CONCLUSIONS: On the basis of the existing trauma of the elbow-forearm system in clinical practice, which is a dominant factor affecting radius-ulna load sharing, the elbow joint longitudinal space has been found to be the occult factor affecting radius-ulna load sharing. The stability and load sharing of radius and ulna after three kinds of smart fixations of the CPBF is not only related to the anatomical and biomechanical stability principles of smart internal fixations, but also closely related to postoperative elbow joint longitudinal space.

Concurrent Mechanisms of Hot Electrons and Interfacial Water Molecule Ordering in Plasmon-Enhanced Nitrogen Fixation.

The participation of high-energy hot electrons generated from the non-radiative decay of localized surface plasmons is an important mechanism for promoting catalytic processes. Herein, another vital mechanism associated with the localized surface plasmon resonance (LSPR) effect, significantly contributing to the nitrogen reduction reaction (NRR), is found. That is to say, the LSPR-induced strong localized electric fields can weaken the intermolecular hydrogen bonds and regulate the arrangement of water molecules at the solid-liquid interface. The AuCu pentacle nanoparticles with excellent light absorption ability and the capability to generate strong localized electric fields are chosen to demonstrate this effect. The in situ Raman spectra and theoretical calculations are employed to verify the mechanism at the molecular scale in a nitrogen fixation process. Meanwhile, due to the promoted electron transfer at the interface by the well-ordered interfacial water, as well as the participation of high-energy hot electrons, the optimal catalyst exhibits excellent performance with an NH3 yield of 52.09 µg h-1 cm-2 and Faradaic efficiency (FE) of 45.82% at ─0.20 V versus RHE. The results are significant for understanding the LSPR effect in catalysis and provide a new approach for regulating the reaction process.

Chiral Pearlescent Cellulose Nanocrystals Films with Broad-Range Tunable Optical Properties for Anti-Counterfeiting Applications.

Pearlescent materials are of technological importance in a diverse array of industries from cosmetics to premium paints; however, chiral pearlescent materials remain unexplored. Here, chiral pearlescent films with on-demand iridescence and metallic appearance are simply organized by leveraging vertical pressure to direct the self-assembly of cellulose nanocrystals. The films are formed with a bilayer planar anchored left-handed chiral nematic architecture, in which the bottom layer is featured with a vertical gradient pitch, and the top layer is featured with a uniform pitch. Simultaneous reflection of the rainbow colors and an on-demand color of left-handed polarized light with angle-dependent wavelength and polarization state accounts for the unique optical phenomenon based on experimental observation and theoretical analysis. Such chiroptical property can be readily tuned with architectural design, enabling reproducible optical appearance with high fidelity. Bringing the pearlescence, iridescence, and specular reflection together endows cellulose nanocrystal films with rich and tunable chiroptical properties that can be used for anti-counterfeiting applications. The current work marks the beginning of chiral pearlescent materials from renewable resources, while the pressure-directed self-assembly provides a step toward scalable production.

Anatomical and Biomechanical Stability of Single/Double Screw-Cancellous Bone Fixations of Regan-Morry Type III Ulnar Coronoid Fractures in Adults: CT Measurement and Finite Element Analysis.

OBJECTIVE: At present, it is still uncertain whether single screw has the same stability as double screws in the treatment of ulnar coronal process basal fracture (Regan-Morry type III). So, we aimed to compare the pull-out force and anti-rotation torque of anterior single/double screw-cancellous bone fixation (aSSBF, aDSBF) in this fracture, and further study the influencing factors on anatomical and biomechanical stability of smart screw internal fixations. METHODS: A total of 63 adult volunteers with no history of elbow injury underwent elbow CT scanning with associated three-dimensional reconstruction that enabled the measurements of bone density and fixed length of the proximal ulna and coronoid. The models of coronal process basal fracture, aSSBF and aDSBF, were developed and validated. Using the finite element model test, the sensitivity analysis of pull-out force and rotational torque was carried out. RESULTS: The pull-out force of aSSBF model was positively correlated with the density of the cancellous bone and linearly related to the fixed depth of the screw. The load pattern of pull-out force of aDSBF model was similar to that of aSSBF model. The ultimate torque of aDSBF model was higher than that of aSSBF model, but the load pattern of ultimate torque of both models was similar to each other when the fracture reset was satisfactory, and the screw nut attaches closely to coronoid process. Moreover, with enhancement of initial pre-tightening force, the increase of ultimate torque of both models was small. CONCLUSIONS: In addition to three pull-out stability factors of smart screw fixations, fracture surface fitting degree and nut fitting degree are the other two important anatomical and biomechanical stability factors of smart screw fixations both for rotational stability. When all pull-out stability and rotational stability factors meet reasonable conditions simultaneously, single or double screw fixation methods are stable for the treatments of ulnar coronoid basal fractures.

Gold nanoparticles with helical surface structure transformed from chiral molecules for SERS-active substrates preparation.

Surface-enhanced Raman scattering (SERS) technique has enlarged the application of Raman spectroscopy, and the most crucial problem is the exploration of SERS-active materials. In the paper, a SERS substrate made of helical gold nanoparticles by the directed synthesis of L-glutathione (L-GSH) was proposed. Because of the large surface specific area and the uneven conduction electrons distribution for sharp tips resulted from the complex concave surface and the symmetry breaking structure, The nanostructure has shown an impressive average enhancement factor (EF) of 2.95 × 105 under off-resonant condition. This phenomenon was explained by the experimental results and finite difference time domain (FDTD) method. Finally, the SERS substrates were used to detect thiram on pear with a limit of detection (LOD) of 0.62 mg/kg and R2 of 0.9772. The proposed SERS substrates suggest the potential application of chiral molecules such as amino acids, peptides et al. in the SERS-active materials fabrication.

Tunable Circularly Polarized Luminescence from Inorganic Chiral Photonic Crystals Doped with Quantum Dots.

Chiral semiconductor nanostructures have received enormous attention due to their emerging circularly polarized luminescence (CPL) properties. However, compared with well-studied photoluminescence (PL), the reported CPL is much weaker and more challenging to be modulated. Herein, we describe a new approach for acquiring the intense and tunable CPL from inorganic chiral photonic crystals (CPCs) doped with semiconductor quantum dots (QDs). Unprecedentedly, the sign, position and intensity of CPL peaks can be precisely controlled by manipulating either the photonic band gap of CPCs or luminescence wavelength of QDs and a giant absolute dissymmetry factor |glum | up to 0.25 is obtained. More importantly, the origin of the CPL modulation is clearly elucidated by both experiment and theory. This work lays the foundation for the construction of next-generation high-performance CPL-based devices.

Specific Detection of Carcinoembryonic Antigen Based on Fluorescence Quenching of Hollow Porous Gold Nanoshells with Roughened Surface.

The detection of tumor biomarkers in the early stage is highly desirable for the therapy of cancer. However, rapid, low-cost, sensitive, and selective detection of biomarkers remains a challenge owing to the sequence homology, short length, and low abundance. This Research Article describes the synthesis of a novel carcinoembryonic antigen (CEA) probe using hollow porous gold nanoparticles (HPGNPs) with roughened surface based on fluorescence quenching. For specific detection of CEA, the surface of HPGNP is modified by carboxyl modification, carboxyl activation, and antibody conjugation. Furthermore, to enhance the detection performance, we have systematically optimized the parameters, such as particle size, surfactants, surface roughness, surface hole size, and the molecule-particle distance (MPD). The results demonstrate that the fluorescence quenching efficiency would be enhanced with a larger particle size and surface hole size, roughened surface and a greater MPD. Also, with careful inspection of different surfactants of CTAB and PVP, we find that PVP has the optimal performance on fluorescence quenching. Under these optimized conditions, CEA could be detected with an ultralow detection limit of 1.5 pg/mL, and the probe shows a linear range from 2 to 100 pg/mL. The limit of detection is an order of intensity lower than related methods. Interference experiment results have shown that the influence of the interfering proteins could be neglected in the detection procedure.