An Array of Ferromagnetic Nanoislands Nondestructively Patterned <i>via</i> a Local Phase Transformation by Low-Energy Proton Irradiation

Low-energy proton irradiation was applied to pattern an array of metallic, ferromagnetic nanoislands through the local phase transformation of an oxidic, paramagnetic phase in a complex superlattice composed of repetitions of an oxidic and metallic layer. The irradiation inflicted minimal damage on the structure, resulting in the absence of unwanted defects and side effects. This nondestructive pattern transfer was clearly confirmed by the contrast between irradiated and unirradiated regions in electrical, chemical, and magnetic images. Simulation based on the magnetic properties suggests that this low-energy proton irradiation can nondestructively pattern an array of ferromagnetic islands with 8.2 nm in diameter and 7.4 nm in spacing between islands, which means it can achieve an areal density of ∼3 Tb/in.² with a thermal stability of over 80 <i>k</i>_B<i>T</i>. Such an array is strong enough to overcome the so-called superparamagnetism limit in magnetic recording. The attributes demonstrated here corroborate that proton irradiation can be applied to design and pattern devices on a nanometer scale not only for magnetic but also for electric and optical materials systems in all such systems in which a local phase transformation is available

Analysis of the causes of recurrence after frontalis suspension using silicone rods for congenital ptosis

<div><p>Background</p><p>Silicone rod is a commonly used synthetic suspension material in frontalis suspension surgery to correct blepharoptosis. The most challenging problem and a decisive drawback of the use of silicone rod is a considerable rate of ptosis recurrence after surgery. We examined patients with recurred ptosis and assessed the physical and micromorphological properties of implanted silicone rods to determine the causative mechanisms of recurred ptosis after frontalis suspension using silicone rod.</p><p>Methods</p><p>This is a prospective observational case series of 22 pediatric patients with recurred ptosis after frontalis suspension using silicone rods for congenital ptosis. Implanted silicone rods were observed and removed during the operation for correction of recurred ptosis. The removed silicone rods were physically and micromorphologically evaluated to determine the cause of recurrence.</p><p>Results</p><p>Pretarsal fixation positions migrated upward, whereas suprabrow fixation positions migrated downward during ptosis recurrence. The breaking strength of implanted silicone rods was reduced by approximately 50% during 3 years. Cracks, debris, and loss of homogenous structure with disintegration were observed on scanning electron micrographs of implanted silicone rods in patients with recurred ptosis. Preoperative severe degree of ptosis also contributed to recurred ptosis.</p><p>Conclusions</p><p>Recurrence of ptosis after frontalis suspension using silicone rod was associated with physical changes of implanted silicone rods, including positional migration, weakened tensile strength, and micromorphological changes in combination with patients’ characteristics.</p></div

Hydrogenated monolayer graphene with reversible and tunable wide band gap and its field-effect transistor

Graphene is currently at the forefront of cutting-edge science and technology due to exceptional electronic, optical, mechanical, and thermal properties. However, the absence of a sizeable band gap in graphene has been a major obstacle for application. To open and control a band gap in functionalized graphene, several gapping strategies have been developed. In particular, hydrogen plasma treatment has triggered a great scientific interest, because it has been known to be an efficient way to modify the surface of single-layered graphene and to apply for standard wafer-scale fabrication. Here we show a monolayer chemical-vapour-deposited graphene hydrogenated by indirect hydrogen plasma without structural defect and we demonstrate that a band gap can be tuned as wide as 3.9 eV by varying hydrogen coverage. We also show a hydrogenated graphene field-effect transistor, showing that on/off ratio changes over three orders of magnitude at room temperature

Physical changes of implanted silicone rods.

<p>Physical changes of implanted silicone rods.</p

Micromorphological grades of implanted silicone rod, harvested from patients with recurred ptosis.

<p>Micromorphological grades of implanted silicone rod, harvested from patients with recurred ptosis.</p

Results of multiple linear regression analysis for factors influencing recurrence time and the degree of re-drooping.

<p>Results of multiple linear regression analysis for factors influencing recurrence time and the degree of re-drooping.</p

Patients’ characteristics.

<p>Patients’ characteristics.</p

Comparisons of the characteristics between early and late recurrence group^a.

<p>Comparisons of the characteristics between early and late recurrence group<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0171769#t004fn001" target="_blank">^a</a>.</p

Representative creep curve of implanted silicone rod.

<p>Representative creep curve of implanted silicone rod.</p