337 research outputs found
CEMB research: The Force from Within
Determining your readiness for the application process (REU and grad school) How to maximize your likelihood of success through the application process Understanding the perks of being a part of the CEMB The next steps beyond your application
The flyer for the event can be downloaded by clicking on the blue download button
Low Molecular Weight Fluorescent Probes (LMFPs) to Detect the Group 12 Metal Triad
Fluorescence sensing, of d-block elements such as Cu2+, Fe3+, Fe2+, Cd2+, Hg2+, and Zn2+ has significantly increased since the beginning of the 21st century. These particular metal ions play essential roles in biological, industrial, and environmental applications, therefore, there has been a drive to measure, detect, and remediate these metal ions. We have chosen to highlight the low molecular weight fluorescent probes (LMFPs) that undergo an optical response upon coordination with the group 12 triad (Zn2+, Cd2+, and Hg2+), as these metals have similar chemical characteristics but behave differently in the environment
Volatile Organic Compounds and Pulmonary Function in the Third National Health and Nutrition Examination Survey, 1988–1994
BACKGROUND: Volatile organic compounds (VOCs) are present in much higher concentrations indoors, where people spend most of their time, than outdoors and may have adverse health effects. VOCs have been associated with respiratory symptoms, but few studies address objective respiratory end points such as pulmonary function. Blood levels of VOCs may be more indicative of personal exposures than are air concentrations; no studies have addressed their relationship with respiratory outcomes. OBJECTIVE: We examined whether concentrations of 11 VOCs that were commonly identified in blood from a sample of the U.S. population were associated with pulmonary function. METHODS: We used data from 953 adult participants (20–59 years of age) in the Third National Health and Nutrition Examination Survey (1988–1994) who had VOC blood measures as well as pulmonary function measures. Linear regression models were used to evaluate the relationship between 11 VOCs and measures of pulmonary function. RESULTS: After adjustment for smoking, only 1,4-dichlorobenzene (1,4-DCB) was associated with reduced pulmonary function. Participants in the highest decile of 1,4-DCB concentration had decrements of −153 mL [95% confidence interval (CI), −297 to −8] in forced expiratory volume in 1 sec and −346 mL/sec (95% CI, −667 to −24) in maximum mid-expiratory flow rate, compared with participants in the lowest decile. CONCLUSIONS: Exposure to 1,4-DCB, a VOC related to the use of air fresheners, toilet bowl deodorants, and mothballs, at levels found in the U.S. general population, may result in reduced pulmonary function. This common exposure may have long-term adverse effects on respiratory health
Carbon nanotubes for stabilization of nanostructured lipid particles
Carbon nanotubes (CNTs) are increasingly studied for innovative biotechnological applications particularly where they are combined with essential biological materials like lipids. Lipids have been used earlier for enhancing the dispersibility of CNTs in aqueous solutions. Here we report a novel application of CNTs for stabilization of internally self-assembled nanostructured lipid particles of 2–5 μm size. Single-walled (pristine) as well as –OH and –COOH functionalized multi-walled CNTs were employed to produce nanostructured emulsions which stayed stable for months and could be re-dispersed after complete dehydration. Concentrations of CNTs employed for stabilization were very low; moreover CNTs were well-decorated with lipid molecules. These features contribute towards reducing their toxicity and improving biocompatibility for biomedical and pharmaceutical applications. Our approach paves the way for future development of combination therapies employing both CNTs and nanostructured lipid self-assembly together as carriers of different drugs
Placental glucocorticoid receptor isoforms in a sheep model of maternal allergic asthma
Maternal asthma increases the risk of adverse pregnancy outcomes and may affect fetal growth and placental function by differential effects on the expression of glucocorticoid receptor (GR) isoforms, leading to altered glucocorticoid signalling. Our aim was to examine the effect of maternal asthma on placental GR profiles using a pregnant sheep model of asthma. Nine known GR isoforms were detected. There was a significant increase in the expression of placental GR isoforms that are known to have low trans-activational activity in other species including GR A, GR P and GRγ which may result in a pro-inflammatory environment in the presence of allergic asthma
Maternal age effect and severe germ-line bottleneck in the inheritance of human mitochondrial DNA
The manifestation of mitochondrial DNA (mtDNA) diseases depends on the frequency of heteroplasmy (the presence of several alleles in an individual), yet its transmission across generations cannot be readily predicted owing to a lack of data on the size of the mtDNA bottleneck during oogenesis. For deleterious heteroplasmies, a severe bottleneck may abruptly transform a benign (low) frequency in a mother into a disease-causing (high) frequency in her child. Here we present a high-resolution study of heteroplasmy transmission conducted on blood and buccal mtDNA of 39 healthy mother–child pairs of European ancestry (a total of 156 samples, each sequenced at ∼20,000× per site). On average, each individual carried one heteroplasmy, and one in eight individuals carried a disease-associated heteroplasmy, with minor allele frequency ≥1%. We observed frequent drastic heteroplasmy frequency shifts between generations and estimated the effective size of the germ-line mtDNA bottleneck at only ∼30–35 (interquartile range from 9 to 141). Accounting for heteroplasmies, we estimated the mtDNA germ-line mutation rate at 1.3 × 10−8 (interquartile range from 4.2 × 10−9 to 4.1 × 10−8) mutations per site per year, an order of magnitude higher than for nuclear DNA. Notably, we found a positive association between the number of heteroplasmies in a child and maternal age at fertilization, likely attributable to oocyte aging. This study also took advantage of droplet digital PCR (ddPCR) to validate heteroplasmies and confirm a de novo mutation. Our results can be used to predict the transmission of disease-causing mtDNA variants and illuminate evolutionary dynamics of the mitochondrial genome
Search for gravitational waves from binary inspirals in S3 and S4 LIGO data
We report on a search for gravitational waves from the coalescence of compact
binaries during the third and fourth LIGO science runs. The search focused on
gravitational waves generated during the inspiral phase of the binary
evolution. In our analysis, we considered three categories of compact binary
systems, ordered by mass: (i) primordial black hole binaries with masses in the
range 0.35 M(sun) < m1, m2 < 1.0 M(sun), (ii) binary neutron stars with masses
in the range 1.0 M(sun) < m1, m2 < 3.0 M(sun), and (iii) binary black holes
with masses in the range 3.0 M(sun)< m1, m2 < m_(max) with the additional
constraint m1+ m2 < m_(max), where m_(max) was set to 40.0 M(sun) and 80.0
M(sun) in the third and fourth science runs, respectively. Although the
detectors could probe to distances as far as tens of Mpc, no gravitational-wave
signals were identified in the 1364 hours of data we analyzed. Assuming a
binary population with a Gaussian distribution around 0.75-0.75 M(sun), 1.4-1.4
M(sun), and 5.0-5.0 M(sun), we derived 90%-confidence upper limit rates of 4.9
yr^(-1) L10^(-1) for primordial black hole binaries, 1.2 yr^(-1) L10^(-1) for
binary neutron stars, and 0.5 yr^(-1) L10^(-1) for stellar mass binary black
holes, where L10 is 10^(10) times the blue light luminosity of the Sun.Comment: 12 pages, 11 figure
All-sky search for periodic gravitational waves in LIGO S4 data
We report on an all-sky search with the LIGO detectors for periodic
gravitational waves in the frequency range 50-1000 Hz and with the frequency's
time derivative in the range -1.0E-8 Hz/s to zero. Data from the fourth LIGO
science run (S4) have been used in this search. Three different semi-coherent
methods of transforming and summing strain power from Short Fourier Transforms
(SFTs) of the calibrated data have been used. The first, known as "StackSlide",
averages normalized power from each SFT. A "weighted Hough" scheme is also
developed and used, and which also allows for a multi-interferometer search.
The third method, known as "PowerFlux", is a variant of the StackSlide method
in which the power is weighted before summing. In both the weighted Hough and
PowerFlux methods, the weights are chosen according to the noise and detector
antenna-pattern to maximize the signal-to-noise ratio. The respective
advantages and disadvantages of these methods are discussed. Observing no
evidence of periodic gravitational radiation, we report upper limits; we
interpret these as limits on this radiation from isolated rotating neutron
stars. The best population-based upper limit with 95% confidence on the
gravitational-wave strain amplitude, found for simulated sources distributed
isotropically across the sky and with isotropically distributed spin-axes, is
4.28E-24 (near 140 Hz). Strict upper limits are also obtained for small patches
on the sky for best-case and worst-case inclinations of the spin axes.Comment: 39 pages, 41 figures An error was found in the computation of the C
parameter defined in equation 44 which led to its overestimate by 2^(1/4).
The correct values for the multi-interferometer, H1 and L1 analyses are 9.2,
9.7, and 9.3, respectively. Figure 32 has been updated accordingly. None of
the upper limits presented in the paper were affecte
Search for Gravitational Waves Associated with 39 Gamma-Ray Bursts Using Data from the Second, Third, and Fourth LIGO Runs
We present the results of a search for short-duration gravitational-wave
bursts associated with 39 gamma-ray bursts (GRBs) detected by gamma-ray
satellite experiments during LIGO's S2, S3, and S4 science runs. The search
involves calculating the crosscorrelation between two interferometer data
streams surrounding the GRB trigger time. We search for associated
gravitational radiation from single GRBs, and also apply statistical tests to
search for a gravitational-wave signature associated with the whole sample. For
the sample examined, we find no evidence for the association of gravitational
radiation with GRBs, either on a single-GRB basis or on a statistical basis.
Simulating gravitational-wave bursts with sine-gaussian waveforms, we set upper
limits on the root-sum-square of the gravitational-wave strain amplitude of
such waveforms at the times of the GRB triggers. We also demonstrate how a
sample of several GRBs can be used collectively to set constraints on
population models. The small number of GRBs and the significant change in
sensitivity of the detectors over the three runs, however, limits the
usefulness of a population study for the S2, S3, and S4 runs. Finally, we
discuss prospects for the search sensitivity for the ongoing S5 run, and beyond
for the next generation of detectors.Comment: 24 pages, 10 figures, 14 tables; minor changes to text and Fig. 2;
accepted by Phys. Rev.
A Joint Search for Gravitational Wave Bursts with AURIGA and LIGO
The first simultaneous operation of the AURIGA detector and the LIGO
observatory was an opportunity to explore real data, joint analysis methods
between two very different types of gravitational wave detectors: resonant bars
and interferometers. This paper describes a coincident gravitational wave burst
search, where data from the LIGO interferometers are cross-correlated at the
time of AURIGA candidate events to identify coherent transients. The analysis
pipeline is tuned with two thresholds, on the signal-to-noise ratio of AURIGA
candidate events and on the significance of the cross-correlation test in LIGO.
The false alarm rate is estimated by introducing time shifts between data sets
and the network detection efficiency is measured with simulated signals with
power in the narrower AURIGA band. In the absence of a detection, we discuss
how to set an upper limit on the rate of gravitational waves and to interpret
it according to different source models. Due to the short amount of analyzed
data and to the high rate of non-Gaussian transients in the detectors noise at
the time, the relevance of this study is methodological: this was the first
joint search for gravitational wave bursts among detectors with such different
spectral sensitivity and the first opportunity for the resonant and
interferometric communities to unify languages and techniques in the pursuit of
their common goal.Comment: 18 pages, IOP, 12 EPS figure
- …