142 research outputs found
Sea surface temperature and paleo-El Niño events in Santa Barbara Basin, AD 1841-1941
Like pages of a "natural coastal diary", successive layers of anoxic varved sediment in the central Santa Barbara Basin have been used by paleoceanographers to reconstruct aspects of past coastal climate. This report focuses on the end of the "Little Ice Age" (15th to 19th century) and on the beginning of this century, a period known to encompass extreme climate excursions and weather events in the Santa Barbara Basin and other parts of Southern California. El Niño events are known to disrupt Southern California's coastal ecosystems and to cause anomalous weather conditions, but El Niño events in Southern California before 1990 have been largely undocumented
Infusion of five percent dextrose increases mortality and morbidity following six minutes of cardiac arrest in resuscitated dogs
The aim of this study was to assess the effect of dextrose administration during and following cardiac resuscitation on mortality and morbidity. Thirty-one dogs anesthetized with halothane were subjected to six minutes of ventricular fibrillation and were resuscitated with open chest cardiac message. All dogs were successfully resuscitated. Thirteen received no dextrose infusion and were fully ambulatory, eating and drinking at 24 hours. Ten of the 18 dogs receiving an infusion of 5% dextrose died before 24 hours and the eight that survived were profoundly impaired. Significantly greater neurologic deficits were recorded for dogs with higher blood glucose concentrations. We conclude that the inclusion of dextrose in fluids used in resuscitation increases mortality and morbidity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26775/1/0000328.pd
New Beta Cephei Stars from the KELT Project
We present the results of a search for Galactic β Cephei stars, which are massive pulsating stars with both pressure modes and mixed modes. Thus, these stars can serve as benchmarks for seismological studies of the interiors of massive stars. We conducted the search by performing a frequency analysis on the optical light curves of known O- and B-type stars with data from the Kilodegree Extremely Little Telescope exoplanet survey. We identify 113 β Cephei stars, of which 86 are new discoveries, which altogether represent a 70% increase in the number currently known. An additional 97 candidates are identified. Among our targets, we find five new eclipsing binaries and 22 stars with equal frequency spacings suggestive of rotational splitting of nonradial pulsation modes. Candidates for runaway stars among our targets and a number of interesting individual objects are discussed. Most of the known and newly discovered β Cephei stars will be observed by the Transiting Exoplanet Survey Satellite mission, providing by far the most comprehensive observational data set of massive main-sequence pulsating stars of sufficient quality for detailed asteroseismic studies. Future analysis of these light curves has the potential to dramatically increase our understanding of the structure of stellar interiors and the physical processes taking place therein
A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone
Recommended standardized procedures for determining exhaled lower respiratory
nitric oxide and nasal nitric oxide have been developed by task forces of the
European Respiratory Society and the American Thoracic Society. These
recommendations have paved the way for the measurement of nitric oxide to
become a diagnostic tool for specific clinical applications. It would be
desirable to develop similar guidelines for the sampling of other trace gases
in exhaled breath, especially volatile organic compounds (VOCs) which reflect
ongoing metabolism. The concentrations of water-soluble, blood-borne substances
in exhaled breath are influenced by: (i) breathing patterns affecting gas
exchange in the conducting airways; (ii) the concentrations in the
tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations
of the compound. The classical Farhi equation takes only the alveolar
concentrations into account. Real-time measurements of acetone in end-tidal
breath under an ergometer challenge show characteristics which cannot be
explained within the Farhi setting. Here we develop a compartment model that
reliably captures these profiles and is capable of relating breath to the
systemic concentrations of acetone. By comparison with experimental data it is
inferred that the major part of variability in breath acetone concentrations
(e.g., in response to moderate exercise or altered breathing patterns) can be
attributed to airway gas exchange, with minimal changes of the underlying blood
and tissue concentrations. Moreover, it is deduced that measured end-tidal
breath concentrations of acetone determined during resting conditions and free
breathing will be rather poor indicators for endogenous levels. Particularly,
the current formulation includes the classical Farhi and the Scheid series
inhomogeneity model as special limiting cases.Comment: 38 page
New Beta Cephei Stars from the KELT Project
We present the results of a search for Galactic β Cephei stars, which are massive pulsating stars with both pressure modes and mixed modes. Thus, these stars can serve as benchmarks for seismological studies of the interiors of massive stars. We conducted the search by performing a frequency analysis on the optical light curves of known O- and B-type stars with data from the Kilodegree Extremely Little Telescope exoplanet survey. We identify 113 β Cephei stars, of which 86 are new discoveries, which altogether represent a 70% increase in the number currently known. An additional 97 candidates are identified. Among our targets, we find five new eclipsing binaries and 22 stars with equal frequency spacings suggestive of rotational splitting of nonradial pulsation modes. Candidates for runaway stars among our targets and a number of interesting individual objects are discussed. Most of the known and newly discovered β Cephei stars will be observed by the Transiting Exoplanet Survey Satellite mission, providing by far the most comprehensive observational data set of massive main-sequence pulsating stars of sufficient quality for detailed asteroseismic studies. Future analysis of these light curves has the potential to dramatically increase our understanding of the structure of stellar interiors and the physical processes taking place therein
Transcriptomic and proteomic analysis of arbovirus-infected tick cells
Ticks are important vectors of a wide variety of pathogens including protozoa,
bacteria and viruses. Many of the viruses transmitted by ticks are of medical or
veterinary importance including tick-borne encephalitis virus (TBEV) and Crimean-
Congo hemorrhagic fever virus causing disease in humans, and African swine fever
virus and Nairobi sheep disease virus affecting livestock. Although several studies
have elucidated tick antimicrobial mechanisms including cellular immune responses
such as nodulation, encapsulation and phagocytosis and humoral immune responses
such as the JAK/STAT pathway, complement-like proteins, antimicrobial peptides,
lectin like pattern-recognition molecules and lysozymes, very little is known about
the innate immune response of ticks towards viral infection. This study therefore
aimed to identify molecules that might be involved in the response of ticks to viral
infection. The hypothesis was that TBEV infection leads to changes in the expression
of immunity-related transcripts and proteins in Ixodes spp. tick cells and that at least
some of these might be antiviral. Ixodes scapularis-derived cell lines IDE8 and ISE6
were chosen since I. scapularis is currently the only tick species with a sequenced
genome and an Ixodes ricinus-derived cell line, IRE/CTVM19, was used because I.
ricinus is the natural vector of TBEV. Basic parameters required to study the
responses of tick cells to infection were determined, including levels of virus
infection, kinetics of virus replication and production, formation of replication
complexes and uptake of dsRNA or siRNA. The cell lines IDE8, ISE6 and
IRE/CTVM19 were infected with either of two tick-borne flaviviruses, TBEV and
Langat virus (LGTV), or with the mosquito-borne alphavirus Semliki Forest virus
(SFV). Infection was characterised using techniques including plaque assay,
luciferase assay, immunostaining and conventional, confocal and electron
microscopy. Two time points for transcriptomics and proteomics analysis of TBEVinfected
IDE8 and IRE/CTVM19 cells were selected: day 2 post-infection (p.i.) when
virus production was increasing and day 6 p.i. when virus production was decreasing.
RNA and protein were isolated from TBEV-infected and mock-infected tick cells at
days 2 and 6 p.i. and RNA-Seq and mass spectrometric technologies were used to
identify changes in, respectively, transcript and protein abundance. Differential
expression of transcripts was determined using the data analysis package DESeq
resulting in a total of 43 statistically significantly differentially expressed transcripts
in IDE8 cells and 83 in IRE/CTVM19 cells, while differential protein representation
using Χ2 test statistics with Bonferroni correction in IDEG6 software resulted in 76
differentially represented proteins in IDE8 cells and 129 in IRE/CTVM19 cells.
These included transcripts and proteins which could affect stages of the virus
infection, including virus entry, replication, maturation and protein trafficking, and
also innate immune responses such as phagocytosis, RNA interference (RNAi), the
complement system, the ubiquitin-proteasome pathway, cell stress and the
endoplasmic reticulum (ER) stress response. After verification of sequencing data by
qRT-PCR, the ability of several of the identified transcripts or proteins to affect virus
infection was determined by knockdown experiments in IDE8 and IRE/CTVM19
cells using wild type LGTV, LGTV replicons or TBEV replicons. Knockdown of
genes encoding proteins including the ER chaperone gp96 and the heat-shock protein
HSP90 resulted in increased virus production in both cell lines, hinting at an antiviral
role. In contrast, knockdown of calreticulin, another ER chaperone, resulted in a
decrease in virus production in IRE/CTVM19 cells but not in IDE8 cells, implying a
requirement for virus production. This functional genomics approach has identified
possible novel genes/proteins involved in the interaction between flaviviruses and
tick cells and also revealed that there might be antiviral innate immune pathways
present in ticks additional to the exogenous RNAi pathway
Comparative Genomic Hybridization (CGH) Reveals a Neo-X Chromosome and Biased Gene Movement in Stalk-Eyed Flies (Genus Teleopsis)
Chromosomal location has a significant effect on the evolutionary dynamics of genes involved in sexual dimorphism, impacting both the pattern of sex-specific gene expression and the rate of duplication and protein evolution for these genes. For nearly all non-model organisms, however, knowledge of chromosomal gene content is minimal and difficult to obtain on a genomic scale. In this study, we utilized Comparative Genomic Hybridization (CGH), using probes designed from EST sequence, to identify genes located on the X chromosome of four species in the stalk-eyed fly genus Teleopsis. Analysis of log2 ratio values of female-to-male hybridization intensities from the CGH microarrays for over 3,400 genes reveals a strongly bimodal distribution that clearly differentiates autosomal from X-linked genes for all four species. Genotyping of 33 and linkage mapping of 28 of these genes in Teleopsis dalmanni indicate the CGH results correctly identified chromosomal location in all cases. Syntenic comparison with Drosophila indicates that 90% of the X-linked genes in Teleopsis are homologous to genes located on chromosome 2L in Drosophila melanogaster, suggesting the formation of a nearly complete neo-X chromosome from Muller element B in the dipteran lineage leading to Teleopsis. Analysis of gene movement both relative to Drosophila and within Teleopsis indicates that gene movement is significantly associated with 1) rates of protein evolution, 2) the pattern of gene duplication, and 3) the evolution of eyespan sexual dimorphism. Overall, this study reveals that diopsids are a critical group for understanding the evolution of sex chromosomes within Diptera. In addition, we demonstrate that CGH is a useful technique for identifying chromosomal sex-linkage and should be applicable to other organisms with EST or partial genomic information
ISOpureR: an R implementation of a computational purification algorithm of mixed tumour profiles
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