Atomic-scale study of TiO2-GR nanohybrid formation by ALD: the effect of the gas phase precursor.

In the present work, we report on a theoretical-computational study of the growth mechanism of the TiO2-Graphene nanohybrid by atomic layer deposition. Hydroxyl groups (OH) are anchoring sites for interacting with the main ALD titanium precursors (Tetrakis (dimethylamino) Titanium, Titanium Tetrachloride, and Titanium Isopropoxide). Results demonstrate that the chemical nature of the precursor directly affects the reaction mechanism in each ALD growth step. Tetrakis(dimethylamino)titanium is the precursor that presents a higher affinity (lower energy barriers for the reaction) to hydroxylated graphene in the growth process. A complete reaction mechanism for each precursor was proposed. The differences between precursors were discussed through the non-covalent interactions index. Finally, the water molecules help reduce the energy barriers and consequently favor the formation of the TiO2-graphene nanohybrid.

Atomic-scale visualization of topological spin textures in the chiral magnet MnGe.

Topological spin textures in chiral magnets such as manganese germanide (MnGe) are of fundamental interest and may enable magnetic storage and computing technologies. Our spin-polarized scanning tunneling microscopy images of MnGe thin films reveal a variety of textures that are correlated to the atomic-scale structure. Our images indicate helical stripe domains, in contrast to bulk, and associated helimagnetic domain walls. In combination with micromagnetic modeling, we can deduce the three-dimensional (3D) orientation of the helical wave vectors, and we find that three helical domains can meet in two distinct ways to produce either a "target-like" or a "π-like" topological spin texture. The target-like texture can be reversibly manipulated through either current/voltage pulsing or applied magnetic field, which represents a promising step toward future applications.

Epidemiology of hospitalised paediatric community-acquired pneumonia and bacterial pneumonia following the introduction of 13-valent pneumococcal conjugate vaccine in the national immunisation programme in Japan.

Studies on community-acquired pneumonia (CAP) and pneumococcal pneumonia (PP) related to the 13-valent pneumococcal conjugate vaccine (PCV13) introduction in Asia are scarce. This study aimed to investigate the epidemiological and microbiological determinants of hospitalised CAP and PP after PCV13 was introduced in Japan. This observational hospital-based surveillance study included children aged ⩽15 years, admitted to hospitals in and around Chiba City, Japan. Participants had bacterial pneumonia based on a positive blood or sputum culture for bacterial pathogens. Serotype and antibiotic-susceptibility testing of Streptococcus pneumoniae and Haemophilus influenzae isolates from patients with bacterial pneumonia were assessed. The CAP hospitalisation rate per 1000 child-years was 17.7, 14.3 and 9.7 in children aged <5 years and 1.18, 2.64 and 0.69 in children aged 5-15 years in 2008, 2012 and 2018, respectively. There was a 45% and 41% reduction in CAP hospitalisation rates, between the pre-PCV7 and PCV13 periods, respectively. Significant reductions occurred in the proportion of CAP due to PP and PCV13 serotypes. Conversely, no change occurred in the proportion of CAP caused by H. influenzae. The incidence of hospitalised CAP in children aged ⩽15 years was significantly reduced after the introduction of PCV13 in Japan. Continuous surveillance is necessary to detect emerging PP serotypes.

Split-mouth evaluation of connective tissue graft with or without enamel matrix derivative for the treatment of isolated gingival recession defects in dogs.

OBJECTIVES: The potential additive effect of an enamel matrix derivative (EMD) to a subepithelial connective tissue graft (CTG) for recession coverage is still controversially discussed. Therefore, the aim of this study was to histologically evaluate the healing of gingival recessions treated with coronally advanced flap (CAF) and CTG with or without EMD in dogs. MATERIALS AND METHODS: Gingival recession defects (5 mm wide and 7 mm deep) were surgically created on the labial side of bilateral maxillary canines in 7 dogs. After 8 weeks of plaque accumulation and subsequent 2 weeks of chemical plaque control, the 14 chronic defects were randomized to receive either CAF with CTG (CAF/CTG) or CAF with CTG and EMD (CAF/CTG/EMD). The animals were sacrificed 10 weeks after reconstructive surgery for histologic evaluation. RESULTS: Treatment with CAF/CTG/EMD demonstrated statistically significantly better results in terms of probing pocket depth reduction (P < 0.05) and clinical attachment level gain (P < 0.001). The length of the epithelium was statistically significantly shorter in the CAF/CTG/EMD group than in the CAF/CTG group (1.00 ± 0.75 mm vs. 2.38 ± 1.48 mm, respectively, P < 0.01). Cementum formation was statistically significantly greater in the CAF/CTG/EMD group than following treatment with the CAF/CTG group (3.20 ± 0.89 mm vs. 1.88 ± 1.58 mm, respectively, P < 0.01). The CAF/CTG/EMD group showed statistically significantly greater complete periodontal regeneration (i.e., new cementum, new periodontal ligament, and new bone) than treatment with CAF/CTG (0.54 ± 0.73 mm vs. 0.07 ± 0.27 mm, respectively, P < 0.05). CONCLUSION: Within their limits, the present findings indicate that the additional use of EMD in conjunction with CAF + CTG favors periodontal regeneration in gingival recession defects. CLINICAL RELEVANCE: The present findings support the use of EMD combined with CTG and CAF for promoting periodontal regeneration in isolated gingival recession defects.

Conceptualizing the origin of life in terms of evolution.

In this opinion piece, we discuss how to place evolution in the context of origin-of-life research. Our discussion starts with a popular definition: 'life is a self-sustained chemical system capable of undergoing Darwinian evolution'. According to this definition, the origin of life is the same as the origin of evolution: evolution is the 'end' of the origin of life. This perspective, however, has a limitation, in that the ability of evolution in and of itself is insufficient to explain the origin of life as we know it, as indicated by Spiegelman's and Lincoln and Joyce's experiments. This limitation provokes a crucial question: What conditions are required for replicating systems to evolve into life? From this perspective, the origin of life includes the emergence of life through evolution: evolution is a 'means' of the origin of life. After reviewing Eigen's pioneering work on this question, we mention our ongoing work suggesting that a key condition might be conflicting multi-level evolution. Taken together, there are thus two questions regarding the origin of life: how evolution gets started, and how evolution produces life. Evolution is, therefore, at the centre of the origin of life, where the two lines of enquiry must meet.This article is part of the themed issue 'Reconceptualizing the origins of life'.

Symmetric Peripheral Running Sutures are Superior to Asymmetric Peripheral Running Sutures for Increasing the Tendon Strength in Flexor Tendon Repair.

BACKGROUND: The fatigue strength of three peripheral suture techniques for flexor tendon repair was compared by cyclic loading of the repairs in the porcine flexor digitorum tendon. METHODS: Thirty-six tendons were sutured using only peripheral sutures with 6-0 Nylon. An initial cyclic load of 10 N for 500 cycles was applied and increased by 10 N for an additional 500 cycles at each new load until rupture. RESULTS: The fatigue strength of the symmetric running peripheral suture was 85.0% and 144.8% greater than that of the two kinds of the asymmetric running peripheral sutures. CONCLUSIONS: Symmetric running sutures can enhance the suture strength and appears to be a useful technique for increasing the strength of the peripheral suture.

Brodie's Abscess of the Radius in a Child.

We herein report an unusual case of Brodie's abscess of the radius in a child. A 13-year-old boy presented with pain on his right distal forearm. A plain radiograph showed an 8 cm translucent lesion in the distal radius. MRI showed a penumbra sign on the T1-weighted image, hyperintensity on T2-weighted images, and ring enhancement on the contrast-enhanced T1 image. 18F-FDG PET/CT images showed an uptake at the margin of the radius. Curettage and iliac cancellous bone grafting were undertaken for Brodie's abscess. Bacteriological examinations were found to be negative, however, the pathologic diagnosis showed chronic osteomyelitis. Eight months after surgery, the patient was asymptomatic and there was no sign of recurrence of infection. For Brodie's abscess in a child, thorough debridement is mandatory in addition to cancellous bone grafting. Brodie's abscess should be considered in the differential diagnosis of a patient who presents with forearm pain and exhibit the radiolucent osteolytic lesion on simple radiography.

Asymmetric six-strand core sutures enhance tendon fatigue strength and the optimal asymmetry.

Under cyclic loading, we recorded the fatigue strength of a six-strand tendon repair with different symmetry in the lengths of suture purchase in two stumps of 120 dental rolls and in 30 porcine tendons. First, the strengths of the repairs with 1, 2, 3, 4 and 5 mm asymmetry were screened using the dental rolls. The asymmetric core suture repairs were then made with a Kessler repair of equal suture purchase (10 mm) in two tendon stumps, and shifting two other Kessler repairs by 1, 3 or 5 mm, respectively, along the longitudinal axis of the tendon in relation to the first (symmetric) Kessler repair. The core repairs with 3 mm or more asymmetry in suture purchases in two tendon ends showed significantly greater fatigue strength and significantly smaller gaps compared with 1 mm asymmetry in core suture repair. Our results support that asymmetric placement of core sutures in two tendon ends favour resisting gapping at the repair site and 3 mm or more asymmetry is needed to produce such beneficial effects.