Can Rigid Femoral Nailing Be Used for Pediatric Femoral Shaft Fracture in Children 8 to 10 Years? Use of RIN in Patients With Femoral Shaft Fracture.

BACKGROUND: The treatment modalities for pediatric femoral shaft fractures are determined by their age, weight, and fracture pattern. Rigid intramedullary nailing (RIN) is usually recommended for patients >11 years of age, and elastic intramedullary nailing (EIN) has been used for patients under 10 years. However, little is known about the use of RIN in patients aged 8 to 10 years. We examined the differences in patients with femoral shaft fractures who were treated with EIN or RIN in terms of (1) fracture healing; (2) changes of anatomic parameters; and (3) related complications. METHODS: We retrospectively reviewed 54 patients between 8 and 10 years of age, with femoral shaft fractures, who were treated with either EIN or RIN between 2011 and 2020. Lateral trochanteric entry was used for RIN procedure. The mean follow-up period was 26.4 months (range, 6 to 113 mo). There were 17 patients in the EIN group and 37 patients in the RIN group. The mean age at the time of surgery was 1 year younger in the EIN group ( P <0.01). The mean weight of the patient was significantly heavier in the RIN group compared with the EIN group. RESULTS: Complete union of the fracture was achieved slightly faster in the RIN group at 3.4 months compared with 3.7 months in the EIN group ( P =0.04). There were no clinically significant changes of the anatomic parameters in either group, including neck shaft angle and articulotrochanteric distance. There was no evidence of avascular necrosis at the time of final follow-up for either group. There were no significant differences in postoperative complications between the groups. CONCLUSION: RIN using lateral trochanteric entry is a feasible surgical option for femoral shaft fractures in patients 8 to 10 years of age that are heavier than 40 kg or with unstable fracture patterns. LEVEL OF EVIDENCE: Level III, retrospective cohort study. See the Guidelines for Authors for a complete description of levels of evidence.

Can low-grade chondrosarcoma in flat bones be treated with intralesional curettage and cryotherapy?

BACKGROUND AND OBJECTIVES: Chondrosarcomas in flat bones are thought to be more aggressive in their behavior, and little is known about intralesional treatment outcomes of low-grade chondrosarcoma in these locations. We tried to find the differences between patients who had low-grade chondrosarcoma in their flat bones versus those with long bone involvement with regard to (1) disease outcome, (2) functional outcome, and (3) treatment complications. METHODS: We retrospectively reviewed 44 patients with primary low-grade chondrosarcoma who were treated with intralesional curettage and cryotherapy. The patients were divided by location of tumor, group I (flat bones, seven patients) and group II (long bones, 37 patients). RESULTS: The local recurrence rate was higher in group I with 5 years disease-free survival of 80.0% in group I and 97.0% in group II (p = 0.001). All recurrent cases were noted to have initially presented with soft tissue extension (Enneking stage IB). The mean Musculoskeletal Tumor Society score at the last follow-up was 21.7 in group I and 27.9 in group II (p = 0.045). CONCLUSIONS: Intralesional curettage and cryotherapy for low-grade chondrosarcoma appear to be a safe and reasonable surgical option for patients with lesions confined to bone (Enneking stage IA). LEVEL OF EVIDENCE: Level III, retrospective cohort study. See the Guidelines for Authors for a complete description of levels of evidence.

A Strategy for Accessing Nanobody-Based Electrochemical Sensors for Analyte Detection in Complex Media.

Nanobodies are single variable domain antibodies isolated from camelids and are rapidly distinguishing themselves as ideal recognition elements in biosensors due to their comparative stability, ease of production and isolation, and high binding affinities. However, transducing analyte binding by nanobodies in real time is challenging, as most nanobodies do not directly produce an optical or electrical signal upon target recognition. Here, we report a general strategy to fabricate sensitive and selective electrochemical sensors incorporating nanobodies for detecting target analytes in heterogeneous media, such as cell lysate. Graphite felt can be covalently functionalized with recombinant HaloTag-modified nanobodies. Subsequent encapsulation with a thin layer of a hydrogel using a vapor deposition process affords encapsulated electrodes that directly display a decrease in current upon antigen binding, without added redox mediators. Differential pulse voltammetry affords clear and consistent decreases in electrode current across multiple electrode samples for specific antigen concentrations. The change in observed current vs increasing antigen concentration follows Langmuir binding characteristics, as expected. Importantly, selective and repeatable target binding in unpurified cell lysate is only demonstrated by the encapsulated electrode, with an antigen detection limit of ca. 30 pmol, whereas bare electrodes lacking encapsulation produce numerous false positive signals in control experiments.

Colorimetric Cotton Swab for Viral Protease Detection.

Reporting the activity of a specific viral protease remains an acute need for rapid point-of-care detection strategies that can distinguish active infection from a resolved infection. In this work, we present a simple colorimetric approach for reporting the activity of a specific viral protease through direct color conversion on a cotton swab, which has the potential to be extended to detect the corresponding virus. We use SARS-CoV-2 viral protease as a proof-of-concept model system. We use 4-aminomalachite green (4-AMG) as the base chromophore structure to design a CoV2-AMG reporter, which is selective toward the SARS-CoV-2 Mpro but does not produce any observable color change in the presence of other viral proteases. The color change is observable by the naked eye, as well as smartphone imaging, which affords a lower limit of detection. The simplicity and generalizability of the method could be instrumental in combating future viral outbreaks.

Immobilization of Nanobodies with Vapor-Deposited Polymer Encapsulation for Robust Biosensors.

To produce next-generation, shelf-stable biosensors for point-of-care diagnostics, a combination of rugged biomolecular recognition elements, efficient encapsulants, and innocuous deposition approaches is needed. Furthermore, to ensure that the sensitivity and specificity that are inherent to biological recognition elements are maintained in solid-state biosensing systems, site-specific immobilization chemistries must be invoked such that the function of the biomolecule remains unperturbed. In this work, we present a widely applicable strategy to develop robust solid-state biosensors using emergent nanobody (Nb) recognition elements coupled with a vapor-deposited polymer encapsulation layer. As compared to conventional immunoglobulin G antibodies, Nbs are smaller (12-15 kDa as opposed to ~150 kDa), have higher thermal stability and pH tolerance, boast greater ease of recombinant production, and are capable of binding antigens with high affinity and specificity. Photoinitiated chemical vapor deposition affords thin, protective polymer barrier layers over immobilized Nb arrays that allow for retention of Nb activity and specificity after both storage under ambient conditions and complete desiccation. Most importantly, we also demonstrate that vapor-deposited polymer encapsulation of Nb arrays enables specific detection of target proteins in complex heterogeneous samples, such as unpurified cell lysate, which is otherwise challenging to achieve with bare Nb arrays.

Metal-Free Organic Chromophores Featuring an Ethynyl-Thienothiophene Linker with an n-Hexyl Chain for Translucent Dye-Sensitized Solar Cells.

We report the simple synthesis of two organic chromophores featuring an ethynyl-thienothiophene linker with an n-hexyl chain (CSD-03 and CSD-04), their optical and electrochemical properties, and their use as photosensitizers in dye-sensitized solar cells (DSSCs). Our theoretical and experimental studies show that adding the second thienothiophene allows for narrowing the bandgap of the molecule and thus ensuring more light harvesting in the visible region. The efficiencies of both CSD-03 (5.46 ± 0.03%) and CSD-04 (5.20 ± 0.03%) are comparable to that of N719 (5.92 ± 0.01%) in translucent DSSCs fabricated with 5 µm-thick TiO2 photoanodes.

Coplanar Donor-π-Acceptor Dyes Featuring a Furylethynyl Spacer for Dye-Sensitized Solar Cells.

Coplanar metal-free organic dyes featuring a furylethynyl spacer with different donor residues (MeO-, MeS-, and Me2N-) have been synthesized. Density functional theory (DFT) calculations predicted that the Me2N- residue would facilitate more effective charge transfer from donor to acceptor than the MeO- and MeS- residues. In agreement with DFT calculations, the dye-sensitized solar cells (DSSCs) fabricated with the Me2N- functionalized dye exhibited the best power conversion efficiency (η), 2.88%. Furthermore, the effect of the furan spacer on the photophysical properties and DSSC parameters are discussed in comparison to a previously reported thiophene counterpart.

Wash-stable, oxidation resistant conductive cotton electrodes for wearable electronics.

Commercial, untreated cotton fabrics have been directly silver coated using one-step electroless deposition and, subsequently, conformally encapsulated with a thin layer of poly(perfluorodecylacrylate) (PFDA) using initiated chemical vapor deposition (iCVD). The surface of these PFDA encapsulated fabrics are notably water-repellent while still displaying a surface resistance as low as 0.2 Ω cm-1, making them suitable for incorporation into launderable wearable electronics. X-ray photoelectron spectroscopy confirms that the PFDA encapsulation prevents oxidation of the silver coating, whereas unencapsulated samples display detrimental silver oxidation after a month of air exposure. The wash stability of PFDA-encapsulated, silver-coated cotton is evaluated using accelerated laundering conditions, following established AATCC protocols, and the samples are observed to withstand up to twenty home laundering cycles without notable mechanical degradation of the vapor-deposited PFDA encapsulation. As a proof-of-concept, PFDA-Ag cotton is employed as a top and bottom electrode in a layered, all-fabric triboelectric generator that produces voltage outputs as high as 25 V with small touch actions, such as tapping.

Proximal femoral osteotomy in Legg-Calvé-Perthes disease using a monolateral external fixator: surgical technique, outcome, and complications.

Although external fixation methods have been described for proximal femoral osteotomy for various etiologies, none are dedicated to a single disease entity. Our study introduces a technique of proximal femoral osteotomy and fixation with a monolateral external fixator system in Legg-Calvé-Perthes disease (LCPD). Twenty-three patients (19 males, four females) with LCPD underwent surgery at our institute between 2004 and 2012. Varus osteotomy (group A, 11 hips) and valgus osteotomy (group B, 12 hips) were performed and the monolateral external fixator system was used. The average age of patients at surgery was 13 years (6-23 years) and the mean follow-up duration was 21 months (12-64 months). The mean angular correction of the varus osteotomy in group A was 20° (10°-28°) and the mean medial displacement was 21% (10-49%). The angular correction of valgus osteotomy in group B was 28° (14°-49°) and lateral displacement was 41% (38-58%). The mean fixation time was 14 weeks (8.4-31 weeks). Complications occurred in nine hips (39.1%) and included pin-tract infections (five), hip abduction contracture (one), nonunions (two), and refracture (one). Our surgical technique provides precise correction and stable fixation with minimal intervention. Therefore, the monolateral external fixator could be considered an acceptable alternative fixation device for the correction of proximal femoral deformities in patients with LCPD. LEVEL OF EVIDENCE: Level IV, case series.

Stability Test of White LED with Bilayer Structure of Red InP Quantum Dots and Yellow YAG:Ce3+ Phosphor.

The white-light-emitting diode (white LED), based on the bilayer structure of red InP quantum dots (QDs) with 610 nm peak, and yellow YAG:Ce3+ phosphor with 550 nm peak, were fabricated through a conventional 5050 type LED fabrication process. The white LED exhibited high luminous efficiency of >130 Im/W and high color rendering index of >80 under operating current of 60 mA and color temperature of 5800 K. As an increase of QDs concentrations, the white LED showed higher color rendering index along with lower luminous efficiency, and the energy loss in the reabsorption process between yellow YAG:Ce3+ emission and red QD absorption was observed. As the temperature increases, the x-color coordinates were significantly changed, indicating that the InP QDs still have lower thermal stability. Also our white LED showed about 50% lumen maintenance after 45,000 hours of normal operation.

Transparent Conductive AGZO/Ag/AGZO Multilayers on PET Substrate by Roll-to-Roll Sputtering.

Indium-free Al and Ga-codoped ZnO (AGZO) multilayer films with nanoscale Ag interlayer were deposited by dual target roll-to-roll RF for AGZO and DC sputtering systems for Ag at room temperature for a large scale. The thicknesses of AGZO/Ag/AGZO multilayer were optimized by changing the roll speed: 0.15/1.1/0.15 m/min for AGZO/Ag/AGZO multilayers, respectively. The optimum thicknesses of AGZO/Ag/AGZO multilayer are 9.21, 8.32 and 8.04 nm, respectively. Optimized AGZO/Ag/AGZO multilayer films showed an excellent transparency (84% at 550 nm) and a low sheet resistance (9.2 omega/sq.) on PET substrates for opto-electronic applications. The effects of nanoscale Ag interlayer on optical and electrical properties of AGZO/Ag/AGZO multilayer films were discussed.

Enhanced Near-IR Cutting Performance in the Mixture of Cs(x)WO3 and Sb:SnO2 Nanoparticles.

The Cs(x)WO3 nanoparticles were synthesized at 800 degrees C under a reducing ambient, and then milled up to nanoscale by a high-energy ball planetary miller. They showed a single phase, and a mean particle size of 80 nm. The Cs contents (x) in Cs(x)WO3 nanoparticles were optimized to be x = 0.32 to maximize the shielding performance around the wavelength of 1200 nm. To compensate still lower absorption above the wavelength of 1200 nm, they were mixed with Sb-doped SnO2 nanoparticles. Thus we achieved the visible transmittance of 70% at 540 nm and the near-infrared absorption of 80% at 1000 nm and 94% at 1400 nm.

Optical Properties of Yellow EuSi2O2N2 Nanophosphor.

The EuSi2O2N2 nanophoshor was prepared by high-energy planetary mill. The nanophosphor with 100 nm in a mean size showed a broad yellow emission spectrum with the peak at 557 nm and the half width of 61 nm due to Eu2+ f-d transition. Its excitation spectrum was drastically decreased in shorter and longer wavelength sides. The fabricated white-light-emitting diode by a remote-phosphor structure exhibited the better color rendering index than that of the bulkphosphor, which is similar with that with YAG phosphor.

Fabrication of a Functionally Graded Copper-Zinc Sulfide Phosphor.

Functionally graded materials (FGMs) are compositionally gradient materials. They can achieve the controlled distribution of the desired characteristics within the same bulk material. We describe a functionally graded (FG) metal-phosphor adapting the concept of the FGM; copper (Cu) is selected as a metal and Cu- and Cl-doped ZnS (ZnS:Cu,Cl) is selected as a phosphor and FG [Cu]-[ZnS:Cu,Cl] is fabricated by a very simple powder process. The FG [Cu]-[ZnS:Cu,Cl] reveals a dual-structured functional material composed of dense Cu and porous ZnS:Cu,Cl, which is completely combined through six graded mediating layers. The photoluminescence (PL) of FG [Cu]-[ZnS:Cu,Cl] is insensitive to temperature change. FG [Cu]-[ZnS:Cu,Cl] also exhibits diode characteristics and photo reactivity for 365 nm -UV light. Our FG metal-phosphor concept can pave the way to simplified manufacturing of low-cost and can be applied to various electronic devices.

The Effect of Alendronate Loaded Biphasic Calcium Phosphate Scaffolds on Bone Regeneration in a Rat Tibial Defect Model.

This study investigated the effect of alendronate (Aln) released from biphasic calcium phosphate (BCP) scaffolds. We evaluated the in vitro osteogenic differentiation of Aln/BCP scaffolds using MG-63 cells and the in vivo bone regenerative capability of Aln/BCP scaffolds using a rat tibial defect model with radiography, micro-computed tomography (CT), and histological examination. In vitro studies included the surface morphology of BCP and Aln-loaded BCP scaffolds visualized using field-emission scanning electron microscope, release kinetics of Aln from BCP scaffolds, alkaline phosphatase (ALP) activity, calcium deposition, and gene expression. The in vitro studies showed that sustained release of Aln from the BCP scaffolds consisted of porous microstructures, and revealed that MG-63 cells cultured on Aln-loaded BCP scaffolds showed significantly increased ALP activity, calcium deposition, and gene expression compared to cells cultured on BCP scaffolds. The in vivo studies using radiograph and histology examination revealed abundant callus formation and bone maturation at the site in the Aln/BCP groups compared to the control group. However, solid bony bridge formation was not observed at plain radiographs until 8 weeks. Micro-CT analysis revealed that bone mineral density and bone formation volume were increased over time in an Aln concentration-dependent manner. These results suggested that Aln/BCP scaffolds have the potential for controlling the release of Aln and enhance bone formation and mineralization.

Limb Lengthening in Patients with Achondroplasia.

PURPOSE: Although bilateral lower-limb lengthening has been performed on patients with achondroplasia, the outcomes for the tibia and femur in terms of radiographic parameters, clinical results, and complications have not been compared with each other. We proposed 1) to compare the radiological outcomes of femoral and tibial lengthening and 2) to investigate the differences of complications related to lengthening. MATERIALS AND METHODS: We retrospectively reviewed 28 patients (average age, 14 years 4 months) with achondroplasia who underwent bilateral limb lengthening between 2004 and 2012. All patients first underwent bilateral tibial lengthening, and at 9-48 months (average, 17.8 months) after this procedure, bilateral femoral lengthening was performed. We analyzed the pixel value ratio (PVR) and characteristics of the callus of the lengthened area on serial radiographs. The external fixation index (EFI) and healing index (HI) were computed to compare tibial and femoral lengthening. The complications related to lengthening were assessed. RESULTS: The average gain in length was 8.4 cm for the femur and 9.8 cm for the tibia. The PVR, EFI, and HI of the tibia were significantly better than those of the femur. Fewer complications were found during the lengthening of the tibia than during the lengthening of the femur. CONCLUSION: Tibial lengthening had a significantly lower complication rate and a higher callus formation rate than femoral lengthening. Our findings suggest that bilateral limb lengthening (tibia, followed by femur) remains a reasonable option; however, we should be more cautious when performing femoral lengthening in selected patients.

Developmental pattern of the hip in patients with hereditary multiple exostoses.

BACKGROUND: Coxa valga is a common clinical feature of hereditary multiple exostoses (HME). The current study aimed to determine the unique developmental pattern of the hip in patients with HME and evaluate the factors that influence its progression. METHODS: Thirty patients (57 hips) with HME were divided into two groups according to the Hilgenreiner epiphyseal angle (HEA). Twenty-two patients (44 hips) including 13 men and 9 women were assigned to group 1 (HEA <25°), and 8 patients (13 hips) including 3 men and 5 women were assigned to group 2 (HEA ≥25°). The mean age at the initial presentation was 6.0 (4-12) years with 6.8 (4-11) years of follow-up in group 1, and 10.4 (8-13) years with 5.4 (2-9) years of follow-up in group 2. We measured the HEA, neck-shaft angle (NSA), acetabular index (AI), center-edge angle (CEA), and migration percentage (MP) for radiographic evaluation. RESULTS: Among the hips, 50 (87.7%) hips had coxa valga and 27 (47.4%) hips had abnormal MP (42.1% were borderline and 5.3% were subluxated). There was a significant difference in the HEA and NSA between the groups (p < 0.001 and p < 0.05, respectively). The HEA significantly correlated with the development of the NSA and no correlation was found between the HEA and AI, CEA, and MP. CONCLUSIONS: There was a significant relationship between the HEA at the initial presentation and the NSA at skeletal maturity. We should consider guided growth for patients with lower HEA to prevent significant coxa valga deformity with close follow-up.

Self-assembly behavior of alkylated isophthalic acids revisited: concentration in control and guest-induced phase transformation.

The engineering of two-dimensional crystals by physisorption-based molecular self-assembly at the liquid-solid interface is a powerful method to functionalize and nanostructure surfaces. The formation of high-symmetry networks from low-symmetry building blocks is a particularly important target. Alkylated isophthalic acid (ISA) derivatives are early test systems, and it was demonstrated that to produce a so-called porous hexagonal packing of plane group p6, i.e., a regular array of nanowells, either short alkyl chains or the introduction of bulky groups within the chains were mandatory. After all, the van der Waals interactions between adjacent alkyl chains or alkyl chains and the surface would dominate the ideal hydrogen bonding between the carboxyl groups, and therefore, a close-packed lamella structure (plane group p2) was uniquely observed. In this contribution, we show two versatile approaches to circumvent this problem, which are based on well-known principles: the "concentration in control" and the "guest-induced transformation" methods. The successful application of these methods makes ISA suitable building blocks to engineer a porous pattern, in which the distance between the pores can be tuned with nanometer precision.

Assessment of skeletal age in multiple epiphyseal dysplasia.

BACKGROUND: Determining the skeletal age in patients with multiple epiphyseal dysplasia (MED) is essential for predicting the adult height and guiding the timing of limb lengthening, epiphysiodesis, and other surgical procedures. In the present study, we examined the patterns of skeletal age delay using 3 different methods, the Greulich-Pyle (GP) atlas method, the Tanner-Whitehouse 3 (TW3) method using radius-ulna-short bones (RUS) scoring system, and the TW3 method using the carpal bone maturity scoring system. METHODS: Left hand radiographs from 23 patients (age range, 3 to 14 y) with MED were examined to determine the skeletal age. We examined the reliability of the 3 different methods and evaluated the difference between the chronological age and the skeletal age. RESULTS: The interobserver and intraobserver reliabilities were higher with the GP atlas method and the TW3 RUS method compared with the TW3 carpal bone maturity scoring system. There was significant skeletal age delay irrespective of the method used (P<0.01). When we used the TW3 carpal method, the pattern of skeletal age delay was significantly distinct from the other 2 methods. According to the measurement method, there was no statistically significant difference in the developmental skeletal age pattern among the COMP gene group, the MATN3 gene group, and other gene groups. CONCLUSIONS: Our findings indicate that there is a distinct skeletal maturation pattern in patients with MED. The skeletal age is relatively delayed compared with the chronological age irrespective of the measuring method utilized. However, use of either the GP atlas or the TW3 RUS method provided more accurate information on the skeletal development in the patients with MED than that provided by the TW3 carpal bone maturity scoring system. LEVEL OF EVIDENCE: Level I. Diagnostic study.

Humidity effect of domain wall roughening behavior in ferroelectric copolymer thin films.

We have demonstrated that domain switching in ferroelectric copolymer films can be significantly affected by humidity. With increasing relative humidity (RH), we observed larger domains with highly irregular boundaries as a result of lateral spreading of the tip-induced electric field that originates from water adsorption. Fractal dimension study of irregular domains reveals that the fractal dimension is higher in cases where the RH is higher. The results show that the RH is one of the major switching parameters in ferroelectric copolymers, and therefore could allow clear understanding with regard to domain switching behavior in the ferroelectric copolymer films under ambient conditions.