13,349 research outputs found
Suppression of cell-spreading and phagocytic activity on nano-pillared surface: in vitro experiment using hemocytes of the colonial ascidian Botryllus schlosseri.
Nano-scale nipple array on the body surface has been described from various invertebrates including endoparasitic and mesoparasitic copepods, but the functions of the nipple array is not well understood. Using the hydrophilized nanopillar sheets made of polystyrene as a mimetic material of the nipple arrays on the parasites\u2019 body surface, we assayed the cell spreading and phagocytosis of the hemocytes of the colonial ascidian Botryllus schlosseri. On the pillared surface, the number of spreading amebocytes and the number of phagocytizing hemocytes per unit area were always smaller than those on the flat surface (Mann-Whitney test, p < 0.05 - 0.001), probably because the effective area for the cell attachment on the pillared surface is much smaller than the area on the flat sheet. The present results supports the idea that the nipple array on the parasites' body surface reduces the innate immune reaction from the host hemocytes
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Epidemiology of gastroschisis: A population-based study in California from 1995 to 2012.
BackgroundAlthough the incidence of gastroschisis is increasing, risk factors are not clearly identified.MethodsUsing the Linked Birth Database from the California Office of Statewide Health Planning and Development from 1995 to 2012, patients with gastroschisis were identified by ICD-9 diagnosis/procedure code or birth certificate designation. Logistic regressions examined demographics, birth factors, and maternal exposures on risk of gastroschisis.ResultsThe prevalence of gastroschisis was 2.7 cases per 10,000 live births. Patients with gastroschisis had no difference in fetal exposure to alcohol (p = 0.609), narcotics (p = 0.072), hallucinogenics (p = 0.239), or cocaine (p = 0.777), but had higher exposure to unspecified/other noxious substances (OR 3.27, p = 0.040; OR 2.02, p = 0.002). Gastroschisis was associated with low/very low birthweight (OR 5.08-16.21, p < 0.001) and preterm birth (OR 3.26-10.0, p < 0.001). Multivariable analysis showed lower risk in black (OR 0.44, p < 0.001), Asian/Pacific Islander (OR 0.76, p = 0.003), and Hispanic patients (OR 0.72, p < 0.001) compared to white patients. Risk was higher in rural areas (OR 1.24-1.76, p = 0.001). Compared to women age < 20, risk decreased with advancing maternal age (OR 0.49-OR 0.03, p < 0.001). Patients with gastroschisis had increased total charges (9012, p < 0.001) and length of stay (38.1 vs. 2.9 days, p < 0.001). Mortality was 4.6%.ConclusionsThis is the largest population-based study summarizing current epidemiology of gastroschisis in California.Type of studyRetrospective comparative cohort study.Level of evidenceIII
First-principles study on dielectric properties of NaCl crystal and ultrathin NaCl films under finite external electric field
We present a first-principles study on the dielectric properties of an NaCl
crystal and ultrathin NaCl films under a finite external electric field. Our
results show that the high-frequency dielectric constant of the films is not
affected by the finite size effect from crystal surfaces and is close to that
of the crystal, whereas the static one is sensitive to the thickness of the
film due to the difference in the atomic configurations between the surface and
inside of the film.Comment: 11 pages and 4 figure
Concentration fluctuations and phase transitions in coupled modulated bilayers
We consider the formation of finite-size domains in lipid bilayers consisting
of saturated and hybrid lipids. First, we describe a monolayer model that
includes a coupling between a compositional scalar field and a two-dimensional
vectorial order-parameter. Such a coupling yields an effective two-dimensional
microemulsion free-energy for the lipid monolayer, and its characteristic
length of compositional modulations can be considered as the origin of
finite-size domains in biological membranes. Next, we consider a coupled
bilayer composed of two modulated monolayers, and discuss the static and
dynamic properties of concentration fluctuations above the transition
temperature. We also investigate the micro-phase separation below the
transition temperature, and compare the micro-phase separated structures with
statics and dynamics of concentration fluctuations above the transition.Comment: 14 pages, 12 figures, 1 tabl
Si/Ge hole-tunneling double-barrier resonant tunneling diodes formed on sputtered flat Ge layers
We have demonstrated Si/Ge hole-tunneling double-barrier resonant tunneling diodes (RTDs) formed on flat Ge layers with a relaxation rate of 89% by our proposed method; in this method, the flat Ge layers can be directly formed on highly B-doped Si(001) substrates using our proposed sputter epitaxy method. The RTDs exhibit clear negative differential resistance effects in the static current–voltage (I–V) curves at room temperature. The quantized energy level estimation suggests that resonance peaks that appeared in the I–V curves are attributed to hole tunneling through the first heavy- and light-hole energy levels
Biologia de ninfas de mosca branca Bemisia tabaci Biótipo B (Hemiptera: Aleyrodidae) em cultivares de soja.
First-Principles Study on Leakage Current through Si/SiO Interface
The relationship between the presence of defects at the stacking structure of
the Si/SiO interface and leakage current is theoretically studied by
first-principles calculation. I found that the leakage current through the
interface with dangling bonds is 530 times larger than that without any
defects, which is expected to lead to dielectric breakdown. The direction of
the dangling bonds is closely related to the performance of the oxide as an
insulator. In addition, it is proved that the termination of the dangling bonds
by hydrogen atoms is effective for reducing the leakage current.Comment: 11 pages. to be published in Phys. Rev.
Wigner crystallization in the two electron quantum dot
Wigner crystallization can be induced in a quantum dot by increasing the
effective electron-electron interaction through a decrease of the electron
density or by the application of a strong magnetic field. We show that the
ground state in both cases is very similar but the energy scales are very
different and therefore also the dynamics.Comment: 4 pages, 4 figure
Sparse Exploratory Factor Analysis
Sparse principal component analysis is a very active research area in the last decade. It produces component loadings with many zero entries which facilitates their interpretation and helps avoid redundant variables. The classic factor analysis is another popular dimension reduction technique which shares similar interpretation problems and could greatly benefit from sparse solutions. Unfortunately, there are very few works considering sparse versions of the classic factor analysis. Our goal is to contribute further in this direction. We revisit the most popular procedures for exploratory factor analysis, maximum likelihood and least squares. Sparse factor loadings are obtained for them by, first, adopting a special reparameterization and, second, by introducing additional [Formula: see text]-norm penalties into the standard factor analysis problems. As a result, we propose sparse versions of the major factor analysis procedures. We illustrate the developed algorithms on well-known psychometric problems. Our sparse solutions are critically compared to ones obtained by other existing methods
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