Oxygen reduction on bimodal nanoporous palladium-copper catalyst synthesized using sacrificial nanoporous copper

Nanoporous copper (NP-Cu), as a sacrificial support, was used for the synthesis of bimodal nanoporous palladium–copper (BNP-PdCu) for oxygen reduction reaction (ORR) electrodes in fuel cells. The catalytic performance of BNP-PdCu in ORR per electrochemical surface area was enhanced by the dissolution and removal of supporting NP-Cu, which indicates that the intrinsic catalytic properties of palladium are improved by the proposed synthesis strategy including galvanic replacement of copper with palladium, following copper dissolution. Cu remained on Pd surfaces even after dissolution of Cu. Additionally, significant local lattice contraction was observed at the ligament surface. First-principles calculations on the adsorbing oxygen species on Pd show that both lattice contraction and alloying with copper increase the binding energies of oxygen species to the Pd surface. The high ORR activity of the present BNP-PdCu is suggested to be mainly due to the Cu-ligand effect

Antibacterial activity of ultrathin platinum islands on flat gold against Escherichia coli

Nanoporous Au exhibits high antibacterial activity (AA) without releasing reactive oxygen species or metal ions, instead its AA depends on the work function (WF) because cell walls are affected by peculiar electronic states at the surface. Based on this mechanism, a flat surface without nanostructure should show high AA if the WF of the surface is suitably tuned. To verify this, ultrathin Pt islands with high WF was fabricated on flat Au by underpotential deposition (UPD) of copper and subsequent redox replacement with Pt, and the AA of the Pt/Au substrate on Escherichia coli was evaluated. The Pt/Au substrate showed higher AA than Pt and Au surfaces, and a positive relationship between AA and WF was demonstrated. In addition, first principles calculations were performed to investigate the mechanism for the high WF of the Pt/Au substrate. The findings suggest that the high WF of the Pt/Au substrate is at least partly due to charge transfer from Au to Pt

Comparison between normal and loose fragment chondrocytes in proliferation and redifferentiation potential

Loose fragments in osteochondritis dissecans (OCD) of the knee require internal fixation. On the other hand, loose fragments derived from spontaneous osteonecrosis of the knee (SONK) are usually removed. However, the difference in healing potential between OCD- and SONK-related loose fragments has not been elucidated. In this study, we investigated proliferative activity and redifferentiation potential of normal cartilage-derived and loose fragment-derived chondrocytes. Cells were prepared from normal articular cartilages and loose fragment cartilages derived from knee OCD and SONK. Cellular proliferation was compared. Redifferentiation ability of pellet-cultured chondrocytes was assessed by real-time PCR analyses. Mesenchymal differentiation potential was investigated by histological analyses. Positive ratio of a stem cell marker CD166 was evaluated in each cartilaginous tissue. Normal and OCD chondrocytes showed a higher proliferative activity than SONK chondrocytes. Chondrogenic pellets derived from normal and OCD chondrocytes produced a larger amount of safranin O-stained proteoglycans compared with SONK-derived pellets. Expression of chondrogenic marker genes was inferior in SONK pellets. The CD166-positive ratio was higher in normal cartilages and OCD loose fragments than in SONK loose fragments. The OCD chondrocytes maintained higher proliferative activity and redifferentiation potential compared with SONK chondrocytes. Our results suggest that chondrogenic properties of loose fragment-derived cells and the amount of CD166-positive cells may affect the repair process of osteochondral defects

Contrast-enhanced Computed Tomography Screening Is Effective for Detecting Venous Thromboembolism not Prevented by Prophylaxis after Total Knee Arthroplasty

Venous thromboembolism (VTE) is a potential complication occurring after total knee arthroplasty (TKA). We investigated the incidence of VTE after TKA using contrast-enhanced computed tomography (CT), and assessed the efficacy of VTE prophylaxis (fondaparinux and enoxaparin). At our hospital, 189 patients (225 knees) underwent TKA between April 2007 and October 2011. The 225 knees were divided into a control group with no VTE prophylaxis (31 cases), a fondaparinux group (107 cases), and an enoxaparin group (87 cases). Contrast-enhanced CT screening for VTE was performed in all cases on day 5 or 6 after TKA. D-dimer levels were measured on day 5 after TKA, and were significantly lower in the fondaparinux (9.8±3.8) and enoxaparin groups (9.4±4.9) than in the control group (15.6±9.8) (p＜0.001). However, no statistically significant difference in the incidence of VTE was observed among the groups (control, 61.3%;fondaparinux, 49.5%;enoxaparin, 50.6%). Prophylaxis was not effective for the prevention of VTE as detected by contrast-enhanced CT after TKA. CT should be performed after TKA, even when VTE prophylaxis is used

Mechanical characterization of nanoporous Au modified with self-assembled monolayers

The surface of nanoporous Au was modified with self-assembled monolayers (SAMs) of 6-mercapto-1-hexanol and the hardness tests were performed on the SAM-modified and non-modified nanoporous Au to investigate the effects of SAM modification on the mechanical properties of nanoporous Au. In addition, the origin of the chemomechanical effects was investigated by first principles shear test simulations on an Au–S alloy. The SAM-modified nanoporous Au showed lower hardness than the non-modified nanoporous Au. The loading rate dependence tests showed that the activation volume was low for both, indicating that events of a short range play an important role in deformation of nanoporous Au, regardless of whether the nanoporous Au was modified with SAMs. It was suggested from the simulations that the lower hardness for the SAM-modified nanoporous Au is because movement of dislocation endpoints at the surface is facilitated by chemical effects of Au–S bonding

A histological study of the medial meniscus posterior root tibial insertion

Purpose/Aim of the study: Posterior root injury of the medial meniscus often leads to articular cartilage degeneration due to altered biomechanics. To avoid dysfunction, the attachment must be repaired using the transtibial pullout technique. To guide appropriate placement of the tibial tunnel, additional details on the normal anatomy of the meniscus insertion are needed. Therefore, we performed a histological analysis of a tibial bone slice with the medial meniscus posterior insertion obtained during total knee arthroplasty surgery. Materials and methods: Horizontal slices of the proximal tibia were obtained from 7 patients with osteoarthritis who underwent total knee arthroplasty. After decalcification, the region of the posterior horn was cut out and segmented into four pieces (2.0 mm thickness; medial to lateral). Sagittal sections were evaluated by safranin O staining or immunohistochemistry with anti-type collagen antibody. Results: Safranin O staining showed that the insertion of the posterior root consisted primarily of fibrocartilaginous layers in segment 2. Anatomically, segment 2 corresponded to the sagittal plane passing through the peak of the medial intercondylar tubercle. In this section, safranin O staining and immunohistochemistry revealed that the anterior one-third of the posterior root insertion was richer in proteoglycans and type II collagen than the central and posterior one-third. Conclusions: Anatomical insertion of the posterior root of the medial meniscus was located at the sagittal plane passing through the peak of the medial intercondylar tubercle. The structure of the medial meniscus posterior insertion was mainly localized in the anterior one-third

Arthroscopic scoring system of meniscal healing following medial meniscus posterior root repair

PURPOSE: Medial meniscus posterior root tear (MMPRT) leads to a rapid degradation of articular cartilage. In the treatment of MMPRT, transtibial pullout repair demonstrates a high clinical survival rate. However, there is no reliable method to evaluate the meniscal healing after surgery. We propose an arthroscopic scoring system for evaluating the meniscal healing status. The aim of this study was to investigate the correlations between second-look arthroscopic scores and clinical outcomes after transtibial pullout repair. METHODS: Twenty patients who had MMPRTs underwent transtibial pullout repairs. Clinical outcomes were assessed using the Japanese Knee Injury and Osteoarthritis Outcome Score (KOOS) and pain score evaluated by visual analogue scale at preoperatively and 1 year postoperatively. The healing status of repaired MM was assessed at one year post-operatively using a semi-quantitative arthroscopic scoring system (total, 10 points) composed of three evaluation criteria: (i) anteroposterior width of bridging tissues, (ii) stability of the MM posterior root, and (iii) synovial coverage of the sutures. Linear regression analysis was used to assess the correlation between second-look arthroscopic scores and clinical outcomes. RESULTS: Transtibial pullout repairs of MMPRTs significantly improved clinical evaluation scores at one year post-operatively. A median of second-look arthroscopic scores was 6.5 (5.75-8). A good correlation was observed between the arthroscopic score and KOOS quality of life (QOL) subscale. A moderate negative correlation between the arthroscopic score and pain score was observed. CONCLUSIONS: This study demonstrated that our semi-quantitative scoring system of meniscal healing correlated with the KOOS QOL subscale following MMPRT transtibial pullout repair. Our results suggest that the second-look arthroscopic score using this system may be a useful scale to determine and compare the healing status of the MM posterior root

Hyaluronan stimulates chondrogenic gene expression in human meniscus cells

As the cost of short-read, high-throughput DNA sequencing continues to fall rapidly, new uses for the technology have been developed aside from its original purpose in determining the genome of various species. Many of these new experiments use the sequencer as a digital counter for measuring biological activities such as gene expression (RNA-Seq) or protein binding (ChIP-Seq). A common problem faced in the analysis of these data is that of sequenced fragments that are "ambiguous", meaning they resemble multiple loci in a reference genome or other sequence. In early analyses, such ambiguous fragments were ignored or were assigned to loci using simple heuristics. However, statistical approaches using maximum likelihood estimation have been shown to greatly improve the accuracy of downstream analyses and have become widely adopted Optimization based on the expectation-maximization (EM) algorithm are often employed by these methods to find the optimal sets of alignments, with frequent enhancements to the model. Nevertheless, these improvements increase complexity, which, along with an exponential growth in the size of sequencing datasets, has led to new computational challenges. Herein, we present our model for ambiguous fragment assignment for RNA-Seq, which includes the most comprehensive set of parameters of any model introduced to date, as well as various methods we have explored for scaling our optimization procedure. These methods include the use of an online EM algorithm and a distributed EM solution implemented on the Spark cluster computing system. Our advances have resulted in the first efficient solution to the problem of fragment assignment in sequencing. Furthermore, we are the first to create a fully generalized model for ambiguous fragment assignment and present details on how our method can provide solutions for additional high-throughput sequencing assays including ChIP-Seq, Allele-Specific Expression (ASE), and the detection of RNA-DNA Differences (RDDs) in RNA-Seq

Single-Session Versus Staged Multivessel Optimal IVUS-Guided PCI in Patients With CCS or NSTE-ACS

[Background] There are no studies comparing single-session vs staged multivessel intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) in patients with chronic coronary syndrome (CCS) or non–ST-segment-elevation acute coronary syndrome (NSTE-ACS). [Objectives] The authors aimed to compare single-session vs staged multivessel IVUS-guided PCI in patients with CCS or NSTE-ACS. [Methods] The OPTIVUS-Complex PCI study multivessel cohort was a prospective multicenter single-arm trial enrolling 1, 021 patients with CCS or NSTE-ACS undergoing multivessel PCI including left anterior descending coronary artery using IVUS aiming to meet the prespecified OPTIVUS criteria for optimal stent expansion. We compared single-session vs staged multivessel PCI. The primary endpoint was a composite of death, myocardial infarction, stroke, or any coronary revascularization. [Results] There were 246 patients (24.1%) undergoing single-session multivessel PCI, and 775 patients (75.9%) undergoing staged multivessel PCI. There was a wide variation in the prevalence of single-session multivessel PCI across the participating centers. The staged multivessel PCI group more often had complex coronary anatomy such as 3-vessel disease, chronic total occlusion, and calcified lesions requiring an atherectomy device compared with the single-session multivessel PCI group. The rates of PCI success, procedural complications, and meeting OPTIVUS criteria were not different between groups. The cumulative 1-year incidence of the primary endpoint was not different between single-session and staged multivessel PCI groups (9.0% vs 10.8%, log-rank P = 0.42). After adjusting confounders, the effect of single-session multivessel PCI relative to staged multivessel PCI was not significant for the primary endpoint (HR: 0.95; 95% CI: 0.58-1.55; P = 0.84). [Conclusions] Single-session and staged multivessel IVUS-guided PCI had similar 1-year outcomes

Optimal Intravascular Ultrasound-Guided Percutaneous Coronary Intervention in Patients With Multivessel Disease

BACKGROUND: Intravascular ultrasound (IVUS) was only rarely used in landmark trials comparing percutaneous coronary intervention (PCI) with coronary artery bypass grafting (CABG) in patients with multivessel disease. OBJECTIVES: The authors aimed to evaluate clinical outcomes after optimal IVUS-guided PCI in patients undergoing multivessel PCI. METHODS: The OPTIVUS (OPTimal IntraVascular UltraSound)-Complex PCI study multivessel cohort was a prospective multicenter single-arm study enrolling 1, 021 patients undergoing multivessel PCI, including left anterior descending coronary artery using IVUS, aiming to meet the prespecified criteria (OPTIVUS criteria: minimum stent area > distal reference lumen area [stent length ≥28mm], and minimum stent area >0.8 × average reference lumen area [stent length <28mm]) for optimal stent expansion. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE) (death/myocardial infarction/stroke/any coronary revascularization). The predefined performance goals were derived from the CREDO-Kyoto (Coronary REvascularization Demonstrating Outcome study in Kyoto) PCI/CABG registry cohort-2 fulfilling the inclusion criteria in this study. RESULTS: In this study, 40.1% of the patients met OPTIVUS criteria in all stented lesions. The cumulative 1-year incidence of the primary endpoint was 10.3% (95% CI: 8.4%-12.2%), which was significantly lower than the predefined PCI performance goal of 27.5% (P < 0.001), and which was numerically lower than the predefined CABG performance goal of 13.8%. The cumulative 1-year incidence of the primary endpoint was not significantly different regardless of meeting or not meeting OPTIVUS criteria. CONCLUSIONS: Contemporary PCI practice conducted in the OPTIVUS-Complex PCI study multivessel cohort was associated with a significantly lower MACCE rate than the predefined PCI performance goal, and with a numerically lower MACCE rate than the predefined CABG performance goal at 1 year