Age-dependent Sagittal Plane Remodeling of Pediatric Supracondylar Fractures.

BACKGROUND: Current treatment guidelines for pediatric supracondylar fractures have not fully accounted for age-related variations in the remodeling potential. This study aimed to explore age-dependent sagittal plane remodeling in supracondylar fractures by assessing cases with residual deformities after treatment. METHODS: This study included 62 patients under 16 years of age treated for supracondylar fractures at our institution from 2002 to 2022. The distance between the posterior and anterior aspects of the capitellar ossific nucleus (CON) was defined as the CON size, while the distance from the anterior humeral line to the posterior aspect of CON was termed DAP-CON. The value obtained by subtracting the DAP-CON on the unfractured side from the DAP-CON on the fractured side was divided by the CON size and multiplied by 100 and termed the displacement of CON (d-CON). The absolute value of the difference between d-CON after intervention and d-CON at the last follow-up was denoted as sagittal plane remodeling. RESULTS: For this patient cohort, the mean age was 5.5 years (range, 1.4 to 14.6 years), and the mean follow-up period was 30.4 months (range, 12.0 to 137.1 months). Sagittal plane remodeling was more pronounced in children younger than 5 years (group I) compared with those older (group II) (P<0.001). In multiple regression analysis, only age at the time of injury was found to be a significant variable (P<0.001). The receiver operating characteristic curve analysis identified 4.2 years as the cutoff age for predicting >33% sagittal plane remodeling, with an area under the curve of 0.975. CONCLUSIONS: Children below the age of 5 years exhibit sagittal plane remodeling, with a cutoff age identified at 4.2 years for achieving >33% of d-CON. This indicates that mild deformities (16.5%

Subchondral Radial and Ulnar K-Wire Positioning With Cancellous Bone Graft Shortens Union Time in Scaphoid Waist Nonunion.

BACKGROUND: Bone grafting in patients with scaphoid waist nonunion can present several technical challenges. In this study, we aimed to present a modified surgical technique for scaphoid waist nonunion, which consisted of subchondral radial and ulnar K-wires positions with cancellous bone graft, and to compare the clinical outcome of this modified technique with the conventional method. METHODS: We retrospectively reviewed 72 patients with scaphoid waist nonunion who had been surgically treated between January 2011 and December 2020. Of these, 34 patients were treated with the modified method and 38 with the conventional method. Debridement of the nonunion site was performed using a curette, rongeur, and microburr. Two or 3 K-wires were inserted along the cancellous portion of the scaphoid in the conventional method. In the modified method, 2 K-wires were inserted along the ulnar and radial subchondral portion of the scaphoid to increase the space for bone grafting in the cancellous portion of the scaphoid. The autologous cancellous bone grafted in both the methods. Demographic, radiological, and clinical outcomes were reviewed and compared between the groups. RESULTS: There were no significant differences in demographics and characteristics of nonunion between the 2 groups of patients. The modified method group showed significantly shorter union time than the conventional method group (conventional group: 13.0 ± 1.3 weeks, modified group: 11.4 ± 1.1 weeks; P < 0.001). The bony union rate was 97.1% for the modified method and 89.5% for the conventional method. Satisfactory clinical outcomes (excellent and good Mayo wrist scores) were achieved in 27 cases (81.8%) using the modified method and 22 cases (64.7%) using the conventional method. CONCLUSION: Subchondral radial and ulnar K-wire positioning with cancellous bone graft (modified method) can improve the union time with satisfactory clinical outcomes in the treatment of scaphoid waist nonunion.

Importance of Whole-Body Scintigraphy or Positron Emission Tomography for Early Detection of Femoral Lesions in Breast Cancer Patients Treated with Bisphosphonates.

Background: We hypothesized that most of the atypical femoral fractures (AFFs) associated with bisphosphonate treatment for breast cancer (BC) could be found before the fracture event in another radiological examination already performed by breast surgeons, rather than on simple radiographs (SRs). Methods: We thoroughly inspected the clinical charts of BC patients treated at our institute between 2008 and 2017. In total, 228 patients were categorized into three groups based on SRs: complete AFF on at least one side (group 1); incomplete fracture on at least one side, but not any complete fracture (group 2); and no suspicious lesion (group X) on either femur. Then, we inspected whole-body scintigraphy (WBS) and positron emission tomography (PET)-computed tomography (CT) images in all groups. For group X, patients with radiological clues from at least one femur were categorized, ultimately, into final group 3 and the rest made up the normal group. Results: About 35% of the patients showed AFFs (complete or incomplete) or suspicious lesions as AFFs, associated with the side effect of Bisphosphonate. In group 1, bilateral lesions (complete or incomplete fractures) were more frequently seen on SRs than unilateral lesions (p = 0.008). The initially identified findings in WBS and PET-CT for the respective complete and incomplete fractures on SRs of groups 1 and 2 were seen at a mean of 7 months previously. SRs did not reveal the lesions in group 3 until 5 months after the initial identification of the lesions in WBS and PET-CT. Conclusions: Even before incomplete AFFs were detectable on SRs, they could be found at check-ups using WBS and PET-CT that had been previously examined by breast surgeons and radiologists for metastasis surveillance. Awareness of the lesions creates an opportunity for prophylactic surgery before complete fractures occur.

Evaluation of overgrowth in pediatric radius fractures.

PURPOSE: Forearm fractures are the most frequent long bone fractures in children. There have been many reports of differences in leg length due to overgrowth in lower extremity fractures. However, reports of such overgrowth in fractures of the upper extremity are rare. The purpose of this study was to investigate the relationship between angulation and overgrowth in pediatric radius fractures. We hypothesized that more angular deformation of the fracture would result in a periosteal transection and more overgrowth. METHODS: Retrospectively, between 2013 and 2022, 14 patients under 16 years of age (mean age 9.43 years; 10 boys, four girls) with unilateral radius shaft or metaphyseal fracture without physeal injury, and a minimum follow-up of 12 months, were included. Demographic factors were analyzed; age, sex, body mass index (BMI), right or left. We evaluated the radiologic parameters; ulnar variances, degree of angularity before intervention, fracture gap and treatment options. The patients underwent conservative or surgical treatment. RESULTS: The mean follow-up period was 27.9 months (range, 13-53 months). Eight patients underwent cast treatment, and six patients underwent surgical treatment. The difference in ulnar variances between the unaffected side and fracture side were statistically significant (P < 0.001). Sex, age, left or right, height, weight, and BMI were not statistically significant. The surgical treatment group (P = 0.013) and the sum of the maximum angularity (P = 0.017) were statistically significant. When the sum of the maximum angularity(SMA) was 30° or more, the ulnar variances were statistically significant, compared with the case where the SMA was less than 30°. The clinical results evaluated at the last outpatient follow-up were good in all patients. CONCLUSIONS: First, this study implies that the degree of angulation of the fracture may affect the overgrowth of the radius in case of radius shaft or metaphyseal fracture, without physeal injury. Second, it implies that the degree of overgrowth may increase with surgical treatment, as opposed to that with conservative treatment. LEVEL OF EVIDENCE: Level IV, Retrospective study.

Enhanced osteogenic differentiation of human mesenchymal stem cells using size-controlled graphene oxide flakes.

Recently, it has been revealed that the physical microenvironment can be translated into cellular mechanosensing to direct human mesenchymal stem cell (hMSC) differentiation. Graphene oxide (GO), a major derivative of graphene, has been regarded as a promising material for stem cell lineage specification due to its biocompatibility and unique physical properties to interact with stem cells. Especially, the lateral size of GO flakes is regarded as the key factor regulating cellular response caused by GO. In this work, GO that had been mechanically created and had an average diameter of 0.9, 1.1, and 1.7 m was produced using a ball-mill process. When size-controlled GO flakes were applied to hMSCs, osteogenic differentiation was enhanced by GO with a specific average diameter of 1.7 µm. It was confirmed that osteogenic differentiation was increased due to the enhanced expression of focal adhesion and the development of focal adhesion subordinate signals via extracellular signal-regulated kinase (ERK)-mitogen-activated protein kinase (MEK) pathway. These results suggest that size-controlled GO flakes could be efficient materials for promoting osteogenesis of hMSCs. Results of this study could also improve our understanding of the correlation between hMSCs and cellular responses to GO.

The incidence of deep vein thrombosis after anterior cruciate ligament reconstruction: An analysis using routine ultrasonography of 260 patients.

BACKGROUND: Recent studies regarding deep vein thrombosis (DVT) after anterior cruciate ligament (ACL) reconstruction investigated only symptomatic complications. The purpose of this study was to assess the true incidence of DVT after ACL reconstruction, regardless of symptom manifestation. MATERIALS AND METHODS: Medical records of 260 patients who underwent isolated ACL reconstruction between January 2014 and December 2019 were retrospectively reviewed. Regardless of symptom manifestation, DVT was examined for all patients at 1 week postoperatively using ultrasonography. Demographics, injury mechanism (high energy direct injury and low energy indirect injury), soft tissue injury, preoperative anterior laxity, tourniquet time, and surgical technique (transtibial, anteromedial portal, and outside-in techniques) were investigated. Soft tissue injury was evaluated on magnetic resonance imaging (MRI) scans, based on the Tscherne classification. Risk factors for proximal DVT were identified using logistic regression analyses. RESULTS: A total of 21 (8.1%) patients showed DVT. 5 (1.9%) patients had thrombosis at the popliteal vein; however, none of them exhibited symptoms. The other 16 patients had thrombosis at the distal veins: 1 patient at the anterior tibial vein, 5 patients at the posterior tibial vein, 3 patients at the peroneal vein, 6 patients at the soleal vein, and 1 patient at the muscular branch vein. The risk factors for proximal DVT included high energy direct injury (p = 0.013, odds ratio = 10.62) and grade 2 soft tissue injury (p = 0.039, odds ratio = 6.78). CONCLUSIONS: The true incidence of DVT, including symptomatic and asymptomatic complications, were 8.1% after ACL reconstruction. This rate is higher than the previously known incidence which has been investigated only for symptomatic patients. Injury mechanism and soft tissue injury should be assessed when considering thromboprophylaxis.

Ulnar shortening osteotomy for posttraumatic ulnar impaction syndrome in adolescent (younger than 18 years) - Based on the Cha & Shin assessment.

PURPOSE: We performed ordinary ulnar shortening osteotomy (USO) in patients younger than 18 years old with secondary ulnar impaction syndrome (UIS) after traumatic events. Here, we report the clinical and radiologic outcomes with a review of the previous literature through a retrospective case series. METHODS: Twenty-two adolescents treated by USOs from 2006 to 2018 were investigated. The amount of shortening was classified into three categories. The first category was for a still open physis on the medial half of the radius in those younger than 15. In this category, we osteotomized the ulna for the physis level to be left neutral or negative by 1-2 mm. The second category had no growth potency in the radius. If the patient was younger than 15, we considered only residual growth of the ulna, thus performing USO for the ordinary UV to be negative by 2-3 mm. For patients aged 15-18 years old, if growth potency was nearly absent in the ulna, we performed traditional USO with a neutral ulnar variance (UV). RESULTS: Categories 1, 2, and 3 for the amount of USO were determined for 4, 4, and 14 patients, respectively. All USOs properly healed without substantial complications. The mean preoperative UV was 2.91 mm, and the final value decreased to 0.23 with statistical significance (p < 0.001). The range of wrist motion was improved after USO from 133.86° and 132.73° to 154.77° and 160.68° (all, p < 0.001 in flexion-extension and pronation-supination arcs, respectively). The preoperative VAS and MMWS scores also improved from 2.77 to 75.00 to 0.18 and 88.86, respectively, at the final follow-up (all, p < 0.001). CONCLUSIONS: UIS in adolescent populations after trauma in their children/younger adolescents could be properly treated by USO. Even with an open physis at the ulna, neutral UVs could be achieved, and the clinical outcomes were satisfactory. However, long-term follow-up is still needed regarding TFCC and DRUJ status. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Optorheological Characteristics of Photosynthetic Bacterium Suspension.

Understanding the rheological behavior of materials is of great importance in science. Here, we report a microscopic foundation for optorheology by manipulating the rheological feature through light. A new phenomenon is observed in the photosynthetic bacterial suspension, that the fluid viscosity changes by light-induced electrons. Type IV pili of photosynthetic bacteria is found, and it allows the electron to transport through the exterior of cells and changes the surface potential of cells, which causes an adjustment in the spatial arrangement of cells in the suspension. When an external electric field is applied, the electric dipole of the cells is induced and their dispersion is changed. The rheological properties are measured to evaluate the internal structure of the suspension depending on the light. The photoelectrons enhance the dispersion of the photosynthetic bacteria in the solution, thus leading to a significant increment in the viscosity. We envision that this discovery will provide new applications to the interface of optics, bioengineering, and rheology.

Remodified Mason-Allen suture technique concomitant with high tibial osteotomy for medial meniscus posterior root tears improved the healing of the repaired root and suppressed osteoarthritis progression.

PURPOSE: To evaluate the results of the remodified Mason-Allen suture technique concomitant with high tibial osteotomy (HTO) for medial meniscal posterior root tears (MMPRTs). The hypothesis was that this procedure would improve clinical results, prevent progression of knee osteoarthritis and increase the healing rate of the repaired root. METHODS: Total 17 patients of mean 51.5 ± 4.4 years who were underwent this combined procedure for MMPRT completed this study. Lysholm and Hospital for Special Surgery (HSS) scores, Kellgren-Lawrence (KL) grade reflecting osteoarthritis progression were evaluated preoperatively and at the last follow-up. Medial meniscus extrusion (MME) was measured on magnetic resonance imaging preoperatively and at mean 26.1 ± 2.3 months postoperatively. Second-look arthroscopy was performed at mean 25.1 ± 5.3 months postoperatively. The healing status of the repaired root was classified as complete, partial and failed healing. The Outerbridge (OB) grade of the medial femoral condyle (MFC) was compared between index surgery and second-look arthroscopy. RESULTS: Mean follow-up duration was 66.4 ± 6.5 months. Mean Lysholm and HSS mean scores improved significantly from preoperatively to the last follow-up: Lysholm: 56.9 ± 5.4 to 83.5 ± 6.0 (P < 0.001); HSS: 56.1 ± 6.0 to 81.7 ± 7.7 (P < 0.001). The mean mechanical alignment of the lower extremity was corrected from varus to the neutral range at the last follow-up. The preoperative KL grade was not significantly different from the KL grade at the last follow-up (P = 0.071). On MRI, mean MME increased from 3.0 ± 0.7 mm to 3.1 ± 0.7 mm (P = 0.046). Second-look arthroscopy showed 64.7% complete, 29.4% partial and 5.9% failed healing of the repaired root. The initial OB grade of the MFC showed no progression (P = 0.103). CONCLUSIONS: The remodified Mason-Allen suture technique concomitant with HTO for MMPRTs significantly improved clinical outcomes and suppressed OA progression at 66.4 months. However, this procedure produced limited complete healing of the repaired roots in 64.7% of patients. LEVEL OF EVIDENCE: IV.

Repeated Dry Sauna Therapy Improves Quality of Life in Obese Korean People.

BACKGROUND: Dry sauna treatments improve the quality of life for chronic pain, congestive heart failure, and type 2 diabetes patients. This study aimed to determine whether dry sauna therapy improved the quality of life of obese people. METHODS: A total of 38 consecutive participants aged over 20 years with a body mass index of ≥25 kg/m2 were recruited for the study. The participants were treated with a 90°C dry sauna for 15 minutes, twice daily for 4 consecutive days. To assess the quality of life, all participants completed the 5 level EQ-5D questionnaires and the EQ-Visual Analog Scale. Study parameters were measured on the same day prior to commencing the sauna sessions in a fasted state and 2 days after the last sauna session. RESULTS: The average age was 62.3±9.5 years; 84.2% of the participants were female. The mean body mass index was 28.5±2.4 kg/m2. Dry sauna significantly improved the mean 5 level EQ-5D index scores from 0.83±0.12 to 0.89±0.11 and increased the mean EQ-Visual Analog Scale from 79.0±15.2 to 91.1±9.7. However, there were no significant changes in body mass index, blood pressure, heart rate, or body composition before and after the 8-session sauna therapy. CONCLUSION: Dry sauna improved the health-related quality of life of obese patients without adverse events. Further clinical studies in larger study populations are needed to verify these findings and provide concrete evidence for obesity treatment.

Facile Synthesis of Co3O4-Incorporated Multichannel Carbon Nanofibers for Electrochemical Applications.

Considering their superior electrochemical performances, extensive studies have been carried out on composite nanomaterials based on porous carbon nanofibers. However, the introduction of inorganic components into a porous structure is complex and has a low yield. In this study, we propose a simple synthesis of cobalt-oxide-incorporated multichannel carbon nanofibers (P-Co-MCNFs) as electrode materials for electrochemical applications. The cobalt oxide component is directly formed in the carbon structure by a simple oxygen plasma exposure of the phase-separated polymer nanofibers. P-Co-MCNF displays high specific capacitance (815 F g-1 at 2.0 A g-1), rate capability (821 F g-1 at 1 A g-1 and 786 F g-1 at 20 A g-1), and cycle stability (92.1% for 5000 cycles) as a supercapacitor electrode. Moreover, excellent sensitivity (down to 1 nM) and selectivity to the glucose molecule is demonstrated for nonenzyme sensor applications.

Risk factors for failure of eradicating infection in a single arthroscopic surgical procedure for septic arthritis of the adult native shoulder with a focus on the volume of irrigation.

BACKGROUND: Septic arthritis of a native joint is relatively rare but is still a challenging and important orthopedic emergency. Most previous reports have focused on the clinical outcomes rather than the risk factors for failure in arthroscopic surgery. METHODS: We retrospectively reviewed the records of patients with septic monoarthritis of the shoulder who underwent arthroscopic irrigation and débridement between January 2007 and January 2019. All patients were divided into 2 groups according to recurrence after a single arthroscopic surgical procedure: eradicated group or recurred group. To identify risk factors affecting the recurrence of septic arthritis of the shoulder after arthroscopic surgery, the following parameters were considered: age; sex; involved side; presentation of rotator cuff tear; volume of irrigation; bacterial organism involved; preoperative erythrocyte sedimentation rate, C-reactive protein level, and white blood cell count in blood and joint fluid; diabetes mellitus; and hypertension. We compared the eradicated and recurred groups regarding the presence of potential risk factors. RESULTS: The study included 97 patients with a mean age of 61 years. Septic arthritis of the shoulder was eradicated completely with a single arthroscopic surgical procedure in 85 patients. However, a second arthroscopic surgical procedure was necessary in 12 patients (12.4%) because of infection recurrence. No significant differences were found between groups except in the volume of irrigation (P < .001). CONCLUSIONS: Most patients with septic arthritis (87.6%) of native shoulders were effectively treated with a single arthroscopic irrigation and débridement. The amount of irrigation may be the most important factor for preventing the need for additional surgical management.

Comparison of low-profile locking plate fixation versus antegrade intramedullary nailing for unstable metacarpal shaft fractures--A prospective comparative study.

BACKGROUND: The purpose of this study was to compare the effectiveness of mini-open antegrade intramedullary nailing (AIN) and open reduction and internal fixation (ORIF) using the low-profile locking plate for angulated metacarpal shaft fractures, through prospective comparative trial. METHODS: Group 1 (mini-open AIN; 40 patients) and the other consecutive patients in group 2 (locking plate; 35 patients) who met our inclusion/exclusion criteria were investigated between January 2010 and December 2016. We compared radiological findings (e.g., union and residual angulation or shortening); clinical conditions (e.g., pain, measured on a visual analog scale (VAS), and Disabilities of the Arm, Shoulder, and Hand (DASH) scores); active range of motion (ROM); and grip strength. RESULTS: Union was achieved in both groups without any major complications. The final angulation measurements were not significantly different (p = 0.402). The final VAS scores were not different (p = 0.868); however, the final DASH score was better in group 1 than in group 2 (p = 0.034). The plates were removed in 14 patients at 9.6 months postoperatively for various reasons. Mean ROM at the time of hardware removal in these 14 patients was significantly lower compared with the final ROM in groups 1 and 2 (non-removal patients). Final grip strengths recovered significantly more in group 1 than in group 2 (p = 0.029). Extension lag was found in four patients in group 2, and the mean amount was 15°; however, it was resolved by tenolysis during hardware removal. CONCLUSIONS: Both mini-open AIN and low-profile plate fixation are excellent options for metacarpal shaft fractures without significant radiological or clinical problems; however, some clinical outcomes evaluated at least 2 years postoperatively, such as DASH scores and grip strength, were better in the AIN group than in the locking plate group. Plate removal was performed under anesthesia in some patients in the plate group for various reasons, and this may have caused the small differences in the final outcomes evaluated 2 years after surgery.

Arthroscopic Treatment for Femoroacetabular Impingement with Extraspinal Diffuse Idiopathic Skeletal Hyperostosis.

BACKGROUND: Patients with extraspinal diffuse idiopathic skeletal hyperostosis (DISH) involving the hip joint have symptoms like femoroacetabular impingement (FAI). To date, no reported study has determined the clinical outcomes of arthroscopic treatment in extraspinal DISH involving the hip joint. METHODS: A total of 421 hips with FAI that underwent arthroscopic treatment were reviewed retrospectively. We determined the extraspinal involvement of DISH with three-dimensional computed tomography (3D-CT) and simple radiography of the pelvis and hip joint. Clinical outcomes were evaluated at a minimum of 2 years postoperatively. The visual analog scale score (VAS), modified Harris hip score (MHHS), and hip outcome score-activity of daily living scale (HOS-ADL) were used, and hip range of motion (ROM) was evaluated pre- and postoperatively and at the time of the final follow-up. RESULTS: Among the 421 hips (372 patients) with FAI that underwent arthroscopic treatment, 17 hips (12 patients, 4.04%) had extraspinal DISH on the hip joints. The mean age of the patients was 51.5 years. The 3D-CT scans and simple radiographs showed extraspinal DISH on multiple points around the pelvis and hip joint. Nine of the 17 hips (seven of 12 patients) had spinal DISH. At the final follow-up, VAS, MHHS, and HOS-ADL improved significantly from 6.5, 65.3, and 66.6, respectively, to 1.2, 87.8, and 89.5, respectively, and hip flexion and internal rotation improved significantly from 97.7° and 7.9°, respectively, to 117.1° and 18.2°, respectively. CONCLUSIONS: This study has demonstrated that extraspinal DISH involving the hip joint could lead to FAI, and arthroscopic treatment could result in relief of symptoms, including pain and ROM limitation, in extraspinal DISH patients.

Highly porous structured polyaniline nanocomposites for scalable and flexible high-performance supercapacitors.

Recently, flexible energy devices have been used to power up portable electronics such as E-skins, smart clothes, and bendable displays. However, the usage of rigid and inactive components in electrode materials limits the application in flexible energy devices. Here, we report a novel method to fabricate porous polyaniline composites (Pt_CPPy/PANI:CSA) using Pt decorated carboxyl polypyrrole nanoparticles (Pt_CPPyNPs) as a nucleating agent for electrodes of supercapacitors. The specific capacitance and electrical conductivity of the Pt_CPPy/PANI:CSA film are 325.0 F g-1 and 814 S cm-1, respectively, which are much higher than those of the pristine PANI:CSA film. Furthermore, the porous PANI:CSA composites exhibit excellent rate capability and cycling stability as the pores in the PANI structure enhance the active surface area between PANI and the ions of the electrolytes. This unique fabrication technique is an effective approach for preparing large scale highly porous polyaniline nanomaterials for diverse electrochemical applications.

Synthesis of Hierarchical Silica/Titania Hollow Nanoparticles and Their Enhanced Electroresponsive Activity.

Wrinkled silica nanoparticle (WSN)-based hollow SiO2/TiO2 nanoparticles (W-HNPs) with hierarchically arrayed internal surfaces were prepared via the combination of sol-gel, TiO2 coating, and etching of core template techniques. The hierarchical internal surface of W-HNPs was attained using WSNs as a core template. Compared with SiO2 sphere-templated hollow SiO2/TiO2 nanoparticles (S-HNPs) with flat inner surfaces, W-HNPs displayed distinctive surface areas, TiO2 loading amounts, and dielectric properties arising from the hierarchical internal surface. The unique properties of W-HNPs were further investigated as an electrorheological (ER) material. W-HNP-based ER fluids exhibited ca. 1.9-fold enhancement in the ER efficiency compared to that of S-HNP-based ER fluids. Such enhancement was attributed to the unique inner surface of W-HNPs, which effectively enhanced the polarizability by increasing the number of charge accumulation sites, and to the presence of the high-dielectric TiO2. This study demonstrated the advantages, in terms of practical ER applications, of hollow nanomaterials having uniquely arrayed internal spaces.

Large Grain-Based Hole-Blocking Layer-Free Planar-Type Perovskite Solar Cell with Best Efficiency of 18.20.

There remains tremendous interest in perovskite solar cells (PSCs) in the solar energy field; the certified power conversion efficiency (PCE) now exceeds 20%. Along with research focused on enhancing PCE, studies are also underway concerning PSC commercialization. It is crucial to simplify the fabrication process and reduce the production cost to facilitate commercialization. Herein, we successfully fabricated highly efficient hole-blocking layer (HBL)-free PSCs through vigorously interrupting penetration of hole-transport material (HTM) into fluorine-doped tin oxide by a large grain based-CH3NH3PbI3 (MAPbI3) film, thereby obtaining a PCE of 18.20%. Our results advance the commercialization of PSCs via a simple fabrication system and a low-cost approach in respect of mass production and recyclability.

Long-term stability improvement of light-emitting diode using highly transparent graphene oxide paste.

A highly transparent paste adhesive is successfully fabricated by introducing graphene oxide (GO) to silicone paste adhesive by using a solvent-exchange method. The GO incorporated in the paste adhesive has a significant role in improving thermal conductivity, transparency and adhesive strength. The GO-embedded silicone paste is applied as a die-attach paste to light-emitting diodes (LEDs) in order to enhance the optical quality of the LEDs. The presence of GO in the die-attach layer of the LEDs gives rise to the enhancement of luminous intensity, effective heat dissipation, improvement of moisture barrier property as well as high adhesive strength. Consequently, the LEDs with the GO-embedded die-attach paste exhibit enhanced long-term stability. This novel approach provides a feasible and effective strategy for improving LED performance.

Electro-response of MoS2 Nanosheets-Based Smart Fluid with Tailorable Electrical Conductivity.

The correlation between electrical conductivity and electro-responsive behavior is identified by introducing few-layer molybdenum disulfide (MoS2) nanosheets to electrorheological (ER) fluid. Few-layer MoS2 nanosheets are successfully fabricated, with a high yield of above 60%, using a straightforward method, and applied to an electro-responsive smart fluid. The electrical conductivity of MoS2 is easily tunable by adjusting the annealing temperature because of its semiconducting behavior. From an in-depth study on the conductivity-dependent ER behavior of few-layer MoS2 nanosheets, it can be verified that an optimum value of the electrical conductivity exists for the electro-responsive material, corresponding to the Wagner model. To the best of our knowledge, this is the first report on the potential of a transition-metal dichalcogenide as a candidate material for an ER fluid. This study may provide promising approaches for the performance improvement of electro-responsive smart fluids.