Anomalous transport in Charney-Hasegawa-Mima flows

Transport properties of particles evolving in a system governed by the Charney-Hasegawa-Mima equation are investigated. Transport is found to be anomalous with a non linear evolution of the second moments with time. The origin of this anomaly is traced back to the presence of chaotic jets within the flow. All characteristic transport exponents have a similar value around $\mu=1.75$, which is also the one found for simple point vortex flows in the literature, indicating some kind of universality. Moreover the law $\gamma=\mu+1$ linking the trapping time exponent within jets to the transport exponent is confirmed and an accumulation towards zero of the spectrum of finite time Lyapunov exponent is observed. The localization of a jet is performed, and its structure is analyzed. It is clearly shown that despite a regular coarse grained picture of the jet, motion within the jet appears as chaotic but chaos is bounded on successive small scales.Comment: revised versio

Adsorption of proteins to thin-films of PDMS and its effect on the adhesion of human endothelial cells

This paper describes a simple and inexpensive procedure to produce thin-films of poly(dimethylsiloxane). Such films were characterized by a variety of techniques (ellipsometry, nuclear magnetic resonance, atomic force microscopy, and goniometry) and used to investigate the adsorption kinetics of three model proteins (fibrinogen, collagen type-I, and bovine serum albumin) under different conditions. The information collected from the protein adsorption studies was then used to investigate the adhesion of human dermal microvascular endothelial cells. The results of these studies suggest that these films can be used to model the surface properties of microdevices fabricated with commercial PDMS. Moreover, the paper provides guidelines to efficiently attach cells in BioMEMS devices.Fil: Chumbimuni Torres, Karin Y.. The University of Texas at San Antonio; Estados UnidosFil: Coronado, Ramon E.. The University of Texas at San Antonio; Estados UnidosFil: Mfuh, Adelphe M.. The University of Texas at San Antonio; Estados UnidosFil: Castro Guerrero, Carlos. The University of Texas at San Antonio; Estados UnidosFil: Silva, María Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Biología Agrícola de Mendoza. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Instituto de Biología Agrícola de Mendoza; ArgentinaFil: Negrete, George R.. The University of Texas at San Antonio; Estados UnidosFil: Bizios, Rena. The University of Texas at San Antonio; Estados UnidosFil: Garcia, Carlos D.. The University of Texas at San Antonio; Estados Unido

Chemical Modification of Ginsenoside on Cell Viability and Cytokine Secretion

Background: Rb1 is a ginsenoside steroid glycoside found exclusively in the plant Panax ginseng. In an earlier report, we showed that Rb1 increased cell proliferation and reduced VEGF (vascular endothelial growth factor) secretion by human retinal pigment epithelial (ARPE19) cells. Objective: In the present study, we hypothesized that chemical modification of Rb1 changes the level of VEGF secretion by ARPE19 cells. Method: Three derivatives of Rb1 were chemically synthesized by hydrogenation (Rb1-H2), acetylation (Rb1-Acyl), and epoxidation (Rb1-Epoxy). Structural modifications were confirmed by 1H Nuclear Magnetic Resonance (NMR) spectra and Mass Spectrometry (MS). To test the biological activity, chemically modified compounds were added to cell culture media and incubated for 72 hours at a concentration of 250 nM at 37°C. Conditioned media were collected and cells were harvested/ counted after treatment. Viable cell numbers were determined by the trypan blue dye exclusion method and VEGF levels by Enzyme-Linked Immunosorbent Assays (ELISA). Results: Consistent with the prior report, results of the present study show Rb1 increased cell proliferation and decreased VEGF secretion. Similar to Rb1\u27s effect on cell proliferation, treatment with Rb1-H2, Rb1-Acyl and Rb1-Epoxy resulted in an increase in cell numbers. In contrast to Rb1- induced decrease in VEGF secretion, treatment with Rb1-H2, Rb-Acyl and Rb1-Epoxy resulted in increased VEGF levels. Conclusion: Chemical modifications of the ginsenoside Rb1 significantly affect the biological activity of VEGF secretion by ARPE19 cells. Additional SAR (Structure Activity Relationship) experiments will be conducted to study the detailed mechanisms by which how specific modifications of Rb1 functional groups alter biological activities

Design and control of photoflash capacitor sharing circuits

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references (leaves 111-112).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.This thesis develops an optimal strategy for charging photoflash capacitors. Photoflash capacitors need to be charged to voltages as high as 350V in low-voltage battery-powered portable devices. With the decreasing size of digital cameras, existing solutions are too large. This thesis will study the operation and losses of a flyback capacitor charger. Specifically, the thesis will focus on minimizing the solution size, given an input current, in addition to keeping efficiency acceptable.by Michael G. Negrete.M.Eng

Absence of DNA Polymerase η Reveals Targeting of C Mutations on the Nontranscribed Strand in Immunoglobulin Switch Regions

Activation-induced cytosine deaminase preferentially deaminates C in DNA on the nontranscribed strand in vitro, which theoretically should produce a large increase in mutations of C during hypermutation of immunoglobulin genes. However, a bias for C mutations has not been observed among the mutations in variable genes. Therefore, we examined mutations in the μ and γ switch regions, which can form stable secondary structures, to look for C mutations. To further simplify the pattern, mutations were studied in the absence of DNA polymerase (pol) η, which may produce substitutions of nucleotides downstream of C. DNA from lymphocytes of patients with xeroderma pigmentosum variant (XP-V) disease, whose polymerase η is defective, had the same frequency of switching to all four γ isotypes and hypermutation in μ-γ switch sites (0.5% mutations per basepair) as control subjects. There were fewer mutations of A and T bases in the XP-V clones, similar to variable gene mutations from these patients, which confirms that polymerase η produces substitutions opposite A and T. Most importantly, the absence of polymerase η revealed an increase in C mutations on the nontranscribed strand. This data shows for the first time that C is preferentially mutated in vivo and pol η generates hypermutation in the μ and γ switch regions

4,10-Diall­yloxy-1,2,3,6b,7,8,9,12b-octa­hydro­perylene

In the title compound, C26H28O2, the central atoms are coplanar, with the –CH2—CH2– links of the cyclo­hexene groups lying to either side of the plane and with the diall­yloxy residues twisted out of this plane [C—C—O—C torsion angles = 16.6 (3) and −13.9 (3)°]. In the crystal structure, mol­ecules are connected into chains propagating in [100] via C—H⋯π inter­actions

The Test Re-Test Reliability of A Novel Single Leg Hop Test (T-Drill Hop Test)

# Background Functional training and testing are an important part of a comprehensive rehabilitation program stressing the neuromuscular system in ways that simulate athletic performance to help determine criteria for return to sport. There are numerous single leg hop tests that have been used for these purposes, however, the validity and clinical relevance has been questioned. Many of the functional performance tests assess only the sagittal plane or forward direction and may only partially assess a person’s athletic abilities. There is a need for reliable and valid functional tests to assess in a multi-directional manner. # Purpose/Hypothesis The purpose of this study is to determine the test re-test reliability of a novel multi-directional timed single leg hop test (T-Drill Hop Test) for use in rehabilitation and performance assessments. # Study Design Cross-sectional reliability study. # Methods Fifty healthy recreationally active college age subjects, (23 males and 27 females) between the ages of 18 and 35, (mean age 23.48 with SD 3.82) consented to perform the test. The subjects hopped along a 10ft. x 10ft. “T” shaped course. Subjects performed two timed maximum effort trials of the T-Drill Hop Test on each leg with an interval of 3-7 days between the two testing days. Intraclass Correlation Coefficients (ICC) were calculated to determine intersession reliability. # Results The inter-rater reliability (ICC’s) for the entire group of 50 subjects ranged between .98 and 1.00 suggesting excellent reliability. The bilateral comparison, utilizing paired t-tests, of the T-Drill Hop Test demonstrated no significant differences between the time scores for the dominant and non-dominant legs for either males or females (p>.05). # Conclusion This study demonstrates the T-Drill Hop Test has excellent test re-test reliability. These results are important prior to validation and utilization as a clinical functional performance test. # Levels of Evidence Level

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Search for narrow resonances in dilepton mass spectra in proton-proton collisions at root s=13 TeV and combination with 8 TeV data

Peer reviewe