3,026 research outputs found
Coarsening model of cavity nucleation and thin film delamination from single-crystal BaTiO3 with proton implantation
The layer splitting mechanism of a proton implanted single crystal ferroelectric BaTiO3 thin film layer from its bulk BaTiO3 substrate has been investigated. The single crystal BaTiO3 thin film layer splits as the hydrogen gas diffuses and the internal cavity pressure increases. Ripening mechanism driven by the pressurized hydrogen in the implantation-induced damage zone makes coarsening of the cavities and causes the delamination of the thin layer during the annealing. A unique criterion relation of blister nucleation and evolution has been derived and a simplified debonding criterion is proposed in terms of dimensionless parameters based on the force equilibrium condition. A numerical simulation of two-bubble evolution and delamination of thin film is performed using a finite element method
Surfactant Therapy for Neonatal Respiratory Distress Syndrome: A Review of Korean Experiences over 17 Years
We undertook a multi-hospital collective study to evaluate outcomes of neonatal respiratory distress syndrome (RDS) patients treated with pulmonary surfactant (PS) over 17 yr in Korea (Group I; 1990/91, Group II; 1996, Group III; 2002, and Group IV; 2007). There were 60 neonates in Group I (16 hospitals), 1,179 in Group II (64), 1,595 in Group III (62), and 1,921 in Group IV (57). We adopted Bomsel's classification to evaluate initial chest radiographic findings, categorized RDS severities, and classified response types to PS therapy. Almost all cases were treated using a single dose in Groups I and II, but 19.5% received multiple-dose therapy in Group IV. In Group IV, Bomsel's stages III and IV composed 62.9% and initial severities of mild, moderate, and severe RDS were 23.0%, 42.0%, and 35.0%. More infants showed good response in Groups II, III, and IV than in Group I (71.7%, 66.8%, and 69.2% vs. 58.3%). Complications and mortality rate were lower in Group IV than in Groups I, II, and III (mortality rate: 14.3% vs. 40.0%, 30.0%, and 18.7%). We conclude that PS therapy in neonates with RDS had a remarkable impact on improving clinical course and outcomes over 17 yr in Korea
Role of remote interfacial phonons in the resistivity of graphene
The temperature () dependence of electrical resistivity in graphene
has been experimentally investigated between 10 and 400 K for samples prepared
on various substrates; HfO, SiO and h-BN. The resistivity of graphene
shows a linear -dependence at low and becomes superlinear above
a substrate-dependent transition temperature. The results are explained by
remote interfacial phonon scattering by surface optical phonons at the
substrates. The use of an appropriate substrate can lead to a significant
improvement in the charge transport of graphene
Clinical Characteristics of Monomorphic Post-transplant Lymphoproliferative Disorders
Post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous group of lymphoproliferative disorders associated with immunosuppression and Epstein-Barr virus infection. PTLD is classified into three major categories: early lesions, polymorphic PTLD, and monomorphic PTLD. The majority of monomorphic PTLD cases are non-Hodgkin's lymphoma of B-cell origin. This retrospective study was conducted to investigate the incidence, clinical manifestation, treatment, and outcomes of monomorphic PTLD among 5,817 recipients of solid organ or allogeneic hematopoietic stem cell transplantation from five institutions. Fourteen patients with monomorphic PTLD were identified (male:female 11:3; median age 42.6 yr, range 24-60). The overall incidence rate was 0.24%. The most common disease type was diffuse large B cell lymphoma (n=7). The median time between the transplant and diagnosis of PTLD was 85.8 months. However, all cases of PTLD after allogeneic hematopoietic stem cell transplantation occurred within 1 yr after transplantation. Ten of the 14 patients had EBV-positive tumor. Fourteen patients received combination systemic chemotherapy and four patients were treated with radiation therapy. Ten patients achieved a complete response (CR) and two patients a partial response (PR). The median follow-up period for surviving patients was 36.6 months. Nine patients remain alive (eight CR, one PR). Nine of 11 solid organ transplantations preserved graft function. The present study indicates a lower incidence rate and a longer median time before the development of PTLD than those of previous reports. Careful monitoring was needed after allogeneic hematopoietic stem cell transplantation for PTLD
Hemophagocytic Lymphohistiocytosis (HLH) Associated with Plasmodium vivax Infection: Case Report and Review of the Literature
Hemophagocytic lymphohistiocytosis (HLH) is an unusual syndrome characterized by fever, hepatosplenomegaly, cytopenias, hypertriglyceridemia, hypofibrinogenemia, and pathologic findings of hemophagocytosis in the bone marrow and other tissues. HLH may be familial or associated with different types of infections, autoimmune disorders, or malignancies. Infection-associated HLH has been reported in various viral, bacterial, fungal, and parasitic infections, and case reports of parasitic infections implicated in HLH include rare cases from Plasmodium vivax infection, which occasionally affects both military personnel and civilians in Korea. We describe an unusual case of HLH resulting from Plasmodium vivax infection and review the literature. This case suggests that clinical suspicion of HLH is important when P. vivax infection is accompanied by cytopenias. Administration of antimalarial drugs may prevent irreversible end organ damage resulting from P. vivax-associated HLH
Pseudogap Behavior Revealed in Interlayer Tunneling in Overdoped BiSrCaCuO
We report heating-compensated interlayer tunneling spectroscopy (ITS)
performed on stacks of overdoped BiSrCaCuO intrinsic
junctions, where most of bias-induced heating in the ITS was eliminated. The
onset temperature of the pseudogap (PG), revealed in the hump structure of the
electronic excitation spectra, reached nearly room temperature for our
overdoped intrinsic junctions, which represented the genuine PG onset. At a
temperature below but close to , both the superconducting coherence peak
and the pseudogap hump coexisted, implying that the two gaps are of separate
origins. The hump voltage increased below , following the superconducting
gap voltage, which led to a conclusion that the hump structure below in
our ITS arose from the combined contribution of the quasiparticle spectral
weights of two different characters; one of the superconducting state and
another of the PG state near the antinodal region.Comment: accepted in Phys. Rev.
- …