Quantification of the number of adsorbed bacteria on an optical waveguide

A simple method is presented for determining the number of bacteria adsorbed on a planar optical waveguide from measurements of a single effective refractive index. It requires only knowledge of the shape and mean size of the bacteria

Surface engineering for biological recognition

The underlying idea of this thesis is that the surface chemical and morphological nature of bacterial strains uniquely differentiates one from another and hence can be used as the basis for their identification and control. It follows that their interactions with an artificial substratum uniquely characterize them. In principle, potentially it is easier and faster to evaluate the interfacial energy between a bacterium and a substratum than to characterize its genome or determine molecular biomarkers characteristic of the strain, hence validation of this thesis opens the way to rapid screening and diagnosis. Auxiliary to this main idea, an advanced metrology for evaluating the interfacial energies has been developed, exploiting the power of kinetic analysis

Exploring users’ behavioral model in Web 2.0 applications - The moderating effects of hedonic versus utilitarian motivations

The Web 2.0 trend has enhanced the overwhelming demand for more pervasive human space in online social interaction. Therefore, it is imperative for the practitioners of Web 2.0 websites to understand users’ motivations to participate and develop specific services to stimulate a long-term usage. This study has proposed a research model that explores the factors affecting users’ intentions to use Web 2.0 applications. In addition, user’s usage motivations (i.e. hedonic versus utilitarian) are also compared. The results revealed that users’ intentions to use Web 2.0 applications is influenced by usefulness, ease of use, enjoyment, and social presence. In addition, users’ hedonic versus utilitarian motivations has the moderating influences on the research model

Effects of using different plasmonic metals in metal/dielectric/metal subwavelength waveguides on guided dispersion characteristics

The fundamental guided dispersion characteristics of guided light in a subwavelength dielectric slit channel embedded by two different plasmonic metals are investigated when varying the gap width. As a result, an overall and salient picture of the guided dispersion characteristics is obtained over a wide spectrum range below and above the plasma frequencies of the two different plasmonic metals, which is important preliminary information for analyzing this type of subwavelength waveguide. In particular, the effects of using two different metals on the guided mode dispersions are emphasized in comparison with the effects of using the same plasmonic metal cladding.Comment: 13 pages, 3 figures, typos corrected, reference added, text modifie

Cryo-EM Studies of TMEM16F Calcium-Activated Ion Channel Suggest Features Important for Lipid Scrambling.

As a Ca2+-activated lipid scramblase and ion channel that mediates Ca2+ influx, TMEM16F relies on both functions to facilitate extracellular vesicle generation, blood coagulation, and bone formation. How a bona fide ion channel scrambles lipids remains elusive. Our structural analyses revealed the coexistence of an intact channel pore and PIP2-dependent protein conformation changes leading to membrane distortion. Correlated to the extent of membrane distortion, many tightly bound lipids are slanted. Structure-based mutagenesis studies further reveal that neutralization of some lipid-binding residues or those near membrane distortion specifically alters the onset of lipid scrambling, but not Ca2+ influx, thus identifying features outside of channel pore that are important for lipid scrambling. Together, our studies demonstrate that membrane distortion does not require open hydrophilic grooves facing the membrane interior and provide further evidence to suggest separate pathways for lipid scrambling and ion permeation

Orbital hemangiopericytoma in an Asian population

Background/PurposeHemangiopericytoma is a very rare orbital tumor. The purpose of this study was to report the clinical and histopathological features of six cases of orbital hemangiopericytoma in an Asian population.MethodsClinical and histopathological features were reviewed in six patients who were histopathologically confirmed as having primary orbital hemangiopericytoma in National Taiwan University Hospital between May 2001 and December 2010.ResultsAmong the six cases who were diagnosed as having primary orbital hemangiopericytoma, all lesions were reported as vascular tumors and featured branching “staghorn appearance” vessels. All patients, including one male and five females, presented with progressive proptosis and some associated symptoms such as extraocular motility limitation with diplopia, displacement of the globe, afferent pupillary defect, congested vessels of conjunctiva, or decreased visual acuity. On computed tomography, the orbital tumors tended to manifest as circumscribed masses with homogeneous medium-to-high enhancement with contrast studies. All six patients received surgical treatments, and four of them had additional radiotherapy. Three patients had recurrence after surgeries, and one of them had multiple metastases to lung and liver. All patients were still alive after a follow-up period of 5–10 years.ConclusionOrbital hemangiopericytoma has malignant potential, which may lead to local recurrence and/or metastasis. Histopathological findings alone are insufficient to predict the behavior of this tumor. Therefore, both clinical and histopathological findings are important to evaluate the treatment outcomes. Total excision accompanied with radiotherapy is suggested and long-term follow-up is required

Triple excitations in Green's function coupled cluster solver for studies of strongly correlated systems in the framework of self-energy embedding theory

Embedding theories became important approaches used for accurate calculations of both molecules and solids. In these theories, a small chosen subset of orbitals is treated with an accurate method, called an impurity solver, capable of describing higher correlation effects. Ideally, such a chosen fragment should contain multiple orbitals responsible for the chemical and physical behavior of the compound. Handing a large number of chosen orbitals presents a very significant challenge for the current generation of solvers used in the physics and chemistry community. Here, we develop a Green's function coupled cluster singles doubles and triples (GFCCSDT) solver that can be used for a quantitative description in both molecules and solids. This solver allows us to treat orbital spaces that are inaccessible to other accurate solvers. At the same time, GFCCSDT maintains high accuracy of the resulting self-energy. Moreover, in conjunction with the GFCCSD solver, it allows us to test the systematic convergence of computational studies. Developing the CC family of solvers paves the road to fully systematic Green's function embedding calculations in solids. In this paper, we focus on the investigation of GFCCSDT self-energies for a strongly correlated problem of SrMnO$_3$ solid. Subsequently, we apply this solver to solid MnO showing that an approximate variant of GFCCSDT is capable of yielding a high accuracy orbital resolved spectral function

Histone deacetylase 2 is required for chromatin condensation and subsequent enucleation of cultured mouse fetal erythroblasts

Background: During the final stages of differentiation of mammalian erythroid cells, the chromatin is condensed and enucleated. We previously reported that Rac GTPases and their downstream target, mammalian homolog of Drosophila diaphanous 2 (mDia2), are required for enucleation of in vitro cultured mouse fetal liver erythroblasts. However, it is not clear how chromatin condensation is achieved and whether it is required for enucleation. Design and Methods: Mouse fetal liver erythroblasts were purified from embryonic day 14.5 pregnant mice and cultured in erythropoietin-containing medium. Enucleation was determined by flow-cytometry based analysis after treatment with histone deacetylase inhibitors or infection with lentiviral short harirpin RNA. Results: We showed that histone deacetylases play critical roles in chromatin condensation and enucleation in cultured mouse fetal liver erythroblasts. Enzymatic inhibition of histone deacetylases by trichostatin A or valproic acid prior to the start of enucleation blocked chromatin condensation, contractile actin ring formation and enucleation. We further demonstrated that histone deacetylases 1, 2, 3 and 5 are highly expressed in mouse fetal erythroblasts. Short hairpin RNA down-regulation of histone deacetylase 2, but not of the other histone deacetylases, phenotypically mimicked the effect of trichostatin A or valproic acid treatment, causing significant inhibition of chromatin condensation and enucleation. Importantly, knock-down of histone deacetylase 2 did not affect erythroblast proliferation, differentiation, or apoptosis. Conclusions: These results identify histone deacetylase 2 as an important regulator, mediating chromatin condensation and enucleation in the final stages of mammalian erythropoiesis.National Institutes of Health (U.S.) (NIH grant P01 HL 32262)Amgen, Inc.National Institutes of Health (U.S.) (Pathway to Independence Award)Leukemia & Lymphoma Society of AmericaTemasek Life Sciences Laborator