Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors

A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and non-evaporable getter pumps has been developed and used to create a cold atomic sample in a chamber that operates with only passive vacuum pumps. The ion-mass spectrum of evaporated gases from the alkali metal dispenser has been recorded as a function of dispenser current. The efficacy of the non-evaporable getter pumps in promoting and maintaining vacuum has been characterized by observation of the Rb vapor optical absorption on the D2 transition at 780 nm and vacuum chamber pressure rate of rise tests. We have demonstrated a sample of laser-cooled Rb atoms in this chamber when isolated and operating without active vacuum pumps

The COOH terminus of the c-Abl tyrosine kinase contains distinct F- and G-actin binding domains with bundling activity

The myristoylated form of c-Abl protein, as well as the P210bcr/abl protein, have been shown by indirect immunofluorescence to associate with F-actin stress fibers in fibroblasts. Analysis of deletion mutants of c-Abl stably expressed in fibroblasts maps the domain responsible for this interaction to the extreme COOH-terminus of Abl. This domain mediates the association of a heterologous protein with F-actin filaments after microinjection into NIH 3T3 cells, and directly binds to F-actin in a cosedimentation assay. Microinjection and cosedimentation assays localize the actin-binding domain to a 58 amino acid region, including a charged motif at the extreme COOH-terminus that is important for efficient binding. F-actin binding by Abl is calcium independent, and Abl competes with gelsolin for binding to F- actin. In addition to the F-actin binding domain, the COOH-terminus of Abl contains a proline-rich region that mediates binding and sequestration of G-actin, and the Abl F- and G-actin binding domains cooperate to bundle F-actin filaments in vitro. The COOH terminus of Abl thus confers several novel localizing functions upon the protein, including actin binding, nuclear localization, and DNA binding. Abl may modify and receive signals from the F-actin cytoskeleton in vivo, and is an ideal candidate to mediate signal transduction from the cell surface and cytoskeleton to the nucleus

Bleeding changes after levonorgestrel 52-mg intrauterine system insertion for contraception in women with self-reported heavy menstrual bleeding.

BackgroundThe levonorgestrel 52-mg intrauterine system has proven efficacy for heavy menstrual bleeding treatment in clinical trials, but few data exist to demonstrate how rapidly the effects occur and the effects in women with self-reported heavy bleeding, as seen commonly in clinical practice.ObjectiveEvaluate changes in bleeding patterns in women with self-reported heavy menstrual bleeding before levonorgestrel 52-mg intrauterine system insertion.Study designA total of 1714 women aged 16-45 years old received a levonorgestrel 52-mg intrauterine system in a multicenter trial evaluating contraceptive efficacy and safety for up to 10 years. At screening, participants described their baseline menstrual bleeding patterns for the previous 3 months. Participants completed daily diaries with subjective evaluation of bleeding information for the first 2 years. For this analysis, we included women with at least 1 complete 28-day cycle of intrauterine system use and excluded women using a hormonal or copper intrauterine contraception in the month prior to study enrollment. We evaluated changes in menstrual bleeding and discontinuation for bleeding complaints per 28-day cycle over 26 cycles (2 years) in women who self-reported their baseline pattern as heavy. We also compared rates of amenorrhea, defined as no bleeding or spotting, within the entire study population in women with subjective heavy menstrual bleeding at baseline compared with those who did not complain of heavy menstrual bleeding.ResultsOf the 1513 women in this analysis, 150 (9.9%) reported baseline heavy menstrual bleeding. The majority of women reported no longer experiencing heavy menstrual bleeding by the end of cycle 1 (112/150, 74.7%) with even greater rates by cycle 2 (124/148, 83.8%). At the end of cycles 6, 13, and 26, 129 of 140 (92.1%; 95% confidence interval, 87.7%-96.6%), 114 of 123 (92.7%; 95% confidence interval, 88.1%-97.3%), and 100 of 103 (97.1%; 95% confidence interval, 93.8%-100%) women reported no heavy menstrual bleeding, respectively. After cycles 13 and 26, 63 of 123 (51.2%; 95% confidence interval, 42.4%-60.1%) and 66 of 103 (64.1%; 95% confidence interval, 54.8%-73.3%), respectively, reported their bleeding as amenorrhea or spotting only. A lower proportion of women with baseline self-reported heavy menstrual bleeding reported amenorrhea as compared with women in the overall study cohort without heavy menstrual bleeding at the end of 6 cycles (319 [25.5%] vs 21 [15.0%], P=.005) and 13 cycles (382 [34.4%] vs 26 [21.1%], P=.003); differences were not significant after 19 cycles (367 [37.2%] vs 36 [31.0%], P=.022) and 26 cycles (383 [43.5%] vs 38 [36.9%], P=.21). Only 4 (2.7%) women with baseline heavy menstrual bleeding discontinued for bleeding complaints (2 for heavy menstrual bleeding and 2 for irregular bleeding), all within the first year.ConclusionMost women who self-report heavy menstrual bleeding experience significant improvement quickly after levonorgestrel 52-mg intrauterine system insertion. Discontinuation for bleeding complaints among women with baseline heavy menstrual bleeding is very low

The gastric acid pocket is attenuated in H. pylori infected subjects

Objective Gastric acid secretory capacity in different anatomical regions, including the postprandial acid pocket, was assessed in Helicobacter pylori positive and negative volunteers in a Western population. Design We studied 31 H. pylori positive and 28 H. pylori negative volunteers, matched for age, gender and body mass index. Jumbo biopsies were taken at 11 predetermined locations from the gastro-oesophageal junction and stomach. Combined high-resolution pH metry (12 sensors) and manometry (36 sensors) was performed for 20 min fasted and 90 min postprandially. The squamocolumnar junction was marked with radio-opaque clips and visualised radiologically. Biopsies were scored for inflammation and density of parietal, chief and G cells immunohistochemically. Results Under fasting conditions, the H. pylori positives had less intragastric acidity compared with negatives at all sensors >1.1 cm distal to the peak lower oesophageal sphincter (LES) pressure (p<0.01). Postprandially, intragastric acidity was less in H. pylori positives at sensors 2.2, 3.3 and 4.4 cm distal to the peak LES pressure (p<0.05), but there were no significant differences in more distal sensors. The postprandial acid pocket was thus attenuated in H. pylori positives. The H. pylori positives had a lower density of parietal and chief cells compared with H. pylori negatives in 10 of the 11 gastric locations (p<0.05). 17/31 of the H. pylori positives were CagA-seropositive and showed a more marked reduction in intragastric acidity and increased mucosal inflammation. Conclusions In population volunteers, H. pylori positives have reduced intragastric acidity which most markedly affects the postprandial acid pocket

\u3cem\u3eChlamydomonas\u3c/em\u3e mutants display reversible deficiencies in flagellar beating and axonemal assembly

Axonemal complexes in flagella are largely prepackaged in the cell body. As such, one mutation often results in the absence of the co-assembled components and permanent motility deficiencies. For example, a Chlamydomonas mutant defective in RSP4 in the radial spoke (RS), which is critical for bend propagation, has paralyzed flagella that also lack the paralogue RSP6 and three additional RS proteins. Intriguingly, recent studies showed that several mutant strains contain a mixed population of swimmers and paralyzed cells despite their identical genetic background. Here we report a cause underlying these variations. Two new mutants lacking RSP6 swim processively and other components appear normally assembled in early log phase indicating that, unlike RSP4, this paralogue is dispensable. However, swimmers cannot maintain the typical helical trajectory and reactivated cell models tend to spin. Interestingly the motile fraction and the spokehead content dwindle during stationary phase. These results suggest that (1) intact RS is critical for maintaining the rhythm of oscillatory beating and thus the helical trajectory; (2) assembly of the axonemal complex with subtle defects is less efficient and the inefficiency is accentuated in compromised conditions, leading to reversible dyskinesia. Consistently, several organisms only possess one RSP4/6 gene. Gene duplication in Chlamydomonas enhances RS assembly to maintain optimal motility in various environments

Brief Note Effects of Diquat on Amphibian Embryo Development

Author Institution: Department of Biology, State University of New York at Fredoni

Seismic stratigraphy of the Ontong Java Plateau

The Ontong Java Plateau, a large, deep-water carbonate plateau in the western equatorial Pacific, is an ideal location for studying responses of carbonate sedimentation to the effects of changing paleoceanographic conditions. These carbonate responses are often reflected in the physical properties of the sediment, which in turn control the appearance of seismic reflection profiles. Seismic stratigraphy analyses, correlating eight reflector horizons to each drill site, have been conducted in an attempt to map stratigraphic data. Accurate correlation of seismic stratigraphic data to drilling results requires conversion of traveltime to depth in meters. Synthetic seismogram models, using shipboard physical properties data, have been generated in an attempt to provide this correlation. Physical properties, including laboratory-measured and well-log data, were collected from sites drilled during Deep Sea Drilling Project Legs 30 and 89, and Ocean Drilling Program Leg 130, on the top and flank of the Ontong Java Plateau. Laboratory-measured density is corrected to in-situ conditions by accounting for porosity rebound resulting from removal of the sediment from its overburden. The correction of laboratory-measured compressional velocity to in situ appears to be largely a function of increases in elastic moduli (especially shear rigidity) with depth of burial, more than a function of changes in temperature, pressure, or density (porosity rebound). Well-log velocity and density data for the ooze intervals were found to be greatly affected by drilling disturbance; hence, they were disregarded and replaced by lab data for these intervals. Velocity and density data were used to produce synthetic seismograms. Correlation of seismic reflection data with synthetic data, and hence with depth below seafloor, at each drill site shows that a single velocity-depth function exists for sediments on the top and flank of the Ontong Java Plateau. A polynomial fit of this function provides an equation for domain conversion: Depth (mbsf) = 44.49 + 0.800(traveltime[ms]) + 3.308 × 10 4 (traveltime[ms]2 ) Traveltime (ms) = -35.18 + 1.118(depth[mbsf]) - 1.969 × KT* (depth[mbsf]2 ) Seismic reflection profiles down the flank of the plateau undergo three significant changes: (1) a drastic thinning of the sediment column with depth, (2) changes in the echo-character of the profile (development of seismic facies), and (3) loss of continuous, coherent reflections. Sediments on the plateau top were largely deposited by pelagic processes, with little significant postdepositional or syndepositional modification. Sediments on the flank of the plateau are also pelagic, but they have been modified by faulting, erosion, and mass movement. These processes result in disrupted and incoherent reflectors, development of seismic facies, and redistribution of sediment on the flank of the plateau. Seismic stratigraphic analyses have shown that the sediment section decreases in thickness by as much as 65% between water depths of 2000 m water depth (at the top of the plateau) and 4000 m (near the base of the plateau). Thinning is attributed to increasing carbonate dissolution with depth. If this assumption is correct, then changes in the relative thicknesses of seismostratigraphic units at each drill site are indicative of changes in the position of the lysocline and the dissolution gradient between the lysocline and the carbonate compensation depth. We think that a shallow lysocline in the early Miocene caused sediment thinning. A deepening of the lysocline in the late-early Miocene caused relative thickening at each site. Within the middle Miocene, a sharp rise in lysoclinal depth occurs, concurrent with a steepening of the dissolution gradient. These events result in sediment thinning at all four sites. The thicker sections in the late Miocene likely correspond to a deepening of the lysocline, and a subsequent rise in the lysocline again hinders accumulation of sediment in the very late Miocene and Pliocene

Bacteria isolated from Bengal cat (Felis catus × Prionailurus bengalensis) anal sac secretions produce volatile compounds potentially associated with animal signaling.

In social animals, scent secretions and marking behaviors play critical roles in communication, including intraspecific signals, such as identifying individuals and group membership, as well as interspecific signaling. Anal sacs are an important odor producing organ found across the carnivorans (species in the mammalian Order Carnivora). Secretions from the anal sac may be used as chemical signals by animals for behaviors ranging from defense to species recognition to signaling reproductive status. In addition, a recent study suggests that domestic cats utilize short-chain free fatty acids in anal sac secretions for individual recognition. The fermentation hypothesis is the idea that symbiotic microorganisms living in association with animals contribute to odor profiles used in chemical communication and that variation in these chemical signals reflects variation in the microbial community. Here we examine the fermentation hypothesis by characterizing volatile organic compounds (VOC) and bacteria isolated from anal sac secretions collected from a male Bengal cat (Felis catus × Prionailurus bengalensis), a cross between the domestic cat and the leopard cat. Both left and right anal sacs of a male Bengal cat were manually expressed (emptied) and collected. Half of the material was used to culture bacteria or to extract bacterial DNA and the other half was used for VOC analysis. DNA was extracted from the anal sac secretions and used for a 16S rRNA gene PCR amplification and sequencing based characterization of the microbial community. Additionally, some of the material was plated out in order to isolate bacterial colonies. Three taxa (Bacteroides fragilis, Tessaracoccus, and Finegoldia magna) were relatively abundant in the 16S rRNA gene sequence data and also isolated by culturing. Using Solid Phase Microextraction (SPME) gas chromatography-mass spectrometry (GC-MS), we tentatively identified 52 compounds from the Bengal cat anal sac secretions and 67 compounds from cultures of the three bacterial isolates chosen for further analysis. Among 67 compounds tentatively identified from bacterial isolates, 51 were also found in the anal sac secretion. We show that the bacterial community in the anal sac consists primarily of only a few abundant taxa and that isolates of these taxa produce numerous volatiles that are found in the combined anal sac volatile profile. Several of these volatiles are found in anal sac secretions from other carnivorans, and are also associated with known bacterial biosynthesis pathways. This is consistent with the fermentation hypothesis and the possibility that the anal sac is maintained at least in part to house bacteria that produce volatiles for the host