559 research outputs found
Venous drainage of the middle lobe of the right lung in man
The shape of the middle lobe of the right lung may vary greatly because of the
varying extent of its surfaces in different specimens and the profuse branching of
the two segmental bronchi, arteries and veins. The architecture of the middle lobe
is therefore especially difficult to understand. For these reasons, attention must be
paid to the arrangements of the veins which separate its segments. Thus, the aim
of this study was to investigate the ways in which venous drainage of the middle
lobe segments may take place. The studies were performed on 40 organs taken
from adult human cadavers of both sexes. The pulmonary vessels and bronchi
were filled with Plastogen G, after which corrosion casts were made and skeletonised.
The lateral segment (SIV) and the medial segment (SV) of the middle lobe
were drained in 55% of specimens by one vein and in 35% of specimens by two
separately terminated veins. Considerably less frequently there were 3 veins (7.5%
of specimens) and only in 2.5% of specimens - 4 veins. In specimens where the
middle lobe was drained by one vein (55%) it was formed by joining the lateral
(V4) and the medial (V5) segmental veins. In 32.5% of specimens these two segmental
veins were formed by a junction of their typical sub-segmental tributaries,
where the posterior sub-segmental vein V4a and the superior sub-segmental vein
V5a were intra-segmental veins, whereas the anterior sub-segmental vein V4b
and the inferior sub-segmental vein V5b were inter-segmental veins. In the
remaining 22.5% of specimens with one vein of the middle lobe we noticed modifications
in the course of the bronchi, arteries and veins. In the middle lobes
drained by two separate veins (35% of specimens) there were independently running
segmental veins, V4 and V5. These were formed by their typical tributaries
(15%), whereas in the remaining 20% of specimens there were unusual patterns.
Three individual veins of the middle lobe (7.5% of specimens) accompanied the
lateral-medial type of bronchial arrangement in 5% of specimens, while in 2.5%
of specimens the bronchial pattern was of the superior-inferior type. These veins
run so as to form more often two superior and one inferior vein. The venous
pattern of the middle lobe was consistent with the bronchial and arterial patterns
in 35% of specimens. However, this conformation was present in those organs
(32.5% of specimens) where the middle lobe was drained by one vein and only in
2.5% of specimens if there were two veins. If 3 or 4 individually emptied veins
were present, we could not find any organ in which the bronchial, arterial and
venous pattern would be fully compatible. Thus, the research revealed that convenient
conditions for the separation of the segments of the middle lobe of the
right lung were present in approximately 1/3 of the middle lobes
Prostaglandin E2 promotes features of replicative senescence in chronically activated human CD8+ T cells.
Prostaglandin E2 (PGE2), a pleiotropic immunomodulatory molecule, and its free radical catalyzed isoform, iso-PGE2, are frequently elevated in the context of cancer and chronic infection. Previous studies have documented the effects of PGE2 on the various CD4+ T cell functions, but little is known about its impact on cytotoxic CD8+ T lymphocytes, the immune cells responsible for eliminating virally infected and tumor cells. Here we provide the first demonstration of the dramatic effects of PGE2 on the progression of human CD8+ T cells toward replicative senescence, a terminal dysfunctional state associated multiple pathologies during aging and chronic HIV-1 infection. Our data show that exposure of chronically activated CD8+ T cells to physiological levels of PGE2 and iso-PGE2 promotes accelerated acquisition of markers of senescence, including loss of CD28 expression, increased expression of p16 cell cycle inhibitor, reduced telomerase activity, telomere shortening and diminished production of key cytotoxic and survival cytokines. Moreover, the CD8+ T cells also produced higher levels of reactive oxygen species, suggesting that the resultant oxidative stress may have further enhanced telomere loss. Interestingly, we observed that even chronic activation per se resulted in increased CD8+ T cell production of PGE2, mediated by higher COX-2 activity, thus inducing a negative feedback loop that further inhibits effector function. Collectively, our data suggest that the elevated levels of PGE2 and iso-PGE2, seen in various cancers and HIV-1 infection, may accelerate progression of CD8+ T cells towards replicative senescence in vivo. Inhibition of COX-2 activity may, therefore, provide a strategy to counteract this effect
Gender Differences in Depression: Assessing Mediational Effects of Overt Behaviors and Environmental Reward through Daily Diary Monitoring
Gender differences in the prevalence of depression are well documented. To further explore the relation between gender and depression, this study used daily diaries to examine gender differences within thirteen behavioral domains and whether differential frequency of overt behaviors and environmental reward mediated the relationship between gender and depression severity. The sample included 82 undergraduate students [66% females; 84% Caucasian; Mean age = 20.2 years]. Overall, females engaged in a significantly greater breadth of behavioral domains and reported a higher level of environmental reward. Females spent more time in the domains of health/hygiene, spiritual activities, and eating with others. Males spent more time in the domains of physical activity, sexual activity, and hobbies and recreational experiences. Females found social activities, passive/sedentary behaviors, eating with others, and engagement in “other” activities more rewarding. Gender had a significant direct effect on depression severity, with females reporting increased depression. This effect was attenuated by the mediator (total environmental reward) such that to the extent females exhibited increased environmental reward, the gender effect on depression was attenuated. These data support behavioral models of depression, indicate increased reinforcement sensitivity among females, and have clinical relevance in the context of assessment and behavioral activation interventions for depression
Using Mussel Isotope Ratios to Assess Anthropogenic Nitrogen Inputs to Freshwater Ecosystems
Stable nitrogen isotope ratios (δ15N) of freshwater mussels from a series of lakes and ponds were related to watershed land use characteristics to assess their utility in determining the source of nitrogen inputs to inland water bodies. Nitrogen isotope ratios measured in freshwater mussels from 19 lakes and ponds in Rhode Island, U.S.A., ranged from 4.9–12.6% and were found to significantly correlate with the fraction of residential development in 100 and 200 m buffer zones around the ponds. Mussel δ15N values in 12 of the 19 ponds also showed significant correlation with average dissolved nitrate concentrations, which ranged from 23–327 μg L-1. These observations, in light of previous studies which link elevated δ15N values of nitrogen derived from septic wastewater with those seen in biota, suggest that mussel isotope ratios may reflect nitrogen source in freshwater ecosystems. We followed an iterative approach using multiple regression analysis to assess the relationship between mussel δ15N and the land use categories fraction residential development, fraction feedlot agriculture, fraction row-crop agriculture, and fraction natural vegetation in 100 and 200 m buffer zones and pond watersheds. From this we developed a simple regression model to predict mussel δ15N from the fraction of residential development in the 200 m buffer zone around the pond. Subsequent testing with data from 16 additional sites in the same ecoregion led us to refine the model by incorporating the fraction of natural vegetation. The overall average absolute difference between measured and predicted δ15N values using the two-parameter model was 1.6%. Potential sources of error in the model include differences in the scale and categorization of land-use data used to generate and test the model, differences in physical characteristics, such as retention time and range of residential development, and exclusion of sources of enriched nitrogen such as runoff from feedlot operations or increased nitrogen loading from inefficient or failed septic systems
Physical properties of InF3-based glasses
Results of X-ray diffraction (XRD), differential scanning calorymetry (DSC), electron probe microanalysis (EPMA) and optical absorption of InF3-based glasses are reported. Different concentrations of rare earth ions have been added to a base glass. XRD results show that no crystalline phases are formed. Characteristic temperatures were determined by DSC and values of glass stability parameters were calculated. Also, the effect of rare earth ions on the thermal stability of InF3-based glasses has been investigated. From the optical absorption measurements and Judd- Ofelt method the intensity parameters have been calculated. In consequence the trends of the intensity parameters are discussed as a function of the number of 4/electrons
ReplicationDomain: a visualization tool and comparative database for genome-wide replication timing data
<p>Abstract</p> <p>Background</p> <p>Eukaryotic DNA replication is regulated at the level of large chromosomal domains (0.5–5 megabases in mammals) within which replicons are activated relatively synchronously. These domains replicate in a specific temporal order during S-phase and our genome-wide analyses of replication timing have demonstrated that this temporal order of domain replication is a stable property of specific cell types.</p> <p>Results</p> <p>We have developed ReplicationDomain <url>http://www.replicationdomain.org</url> as a web-based database for analysis of genome-wide replication timing maps (replication profiles) from various cell lines and species. This database also provides comparative information of transcriptional expression and is configured to display any genome-wide property (for instance, ChIP-Chip or ChIP-Seq data) via an interactive web interface. Our published microarray data sets are publicly available. Users may graphically display these data sets for a selected genomic region and download the data displayed as text files, or alternatively, download complete genome-wide data sets. Furthermore, we have implemented a user registration system that allows registered users to upload their own data sets. Upon uploading, registered users may choose to: (1) view their data sets privately without sharing; (2) share with other registered users; or (3) make their published or "in press" data sets publicly available, which can fulfill journal and funding agencies' requirements for data sharing.</p> <p>Conclusion</p> <p>ReplicationDomain is a novel and powerful tool to facilitate the comparative visualization of replication timing in various cell types as well as other genome-wide chromatin features and is considerably faster and more convenient than existing browsers when viewing multi-megabase segments of chromosomes. Furthermore, the data upload function with the option of private viewing or sharing of data sets between registered users should be a valuable resource for the scientific community.</p
POSSIBILITIES OF OPEN ERUPTION ELIMINATION BY DRILLING TOOLS
The most important raw materials for different industries are oil and natural gas. With increasing consumption, the demand for drilling and the quality of production increases. Therefore, the exploration and production of hydrocarbons requires not only first-class machinery and technological equipment, but also qualified personnel.
Exploration and drilling, production of hydrocarbons, like any other industry, cannot avoid accidents, emergencies and catastrophes. The worst type of well accident is undoubtedly an open eruption of the extracted crude oil. Open eruption can lead to serious injuries to the rig personnel, damage and destruction of equipment, negative environmental impact and loss of crude oil.
Exploratory drilling can cause the rise of pressure and its subsequent manifestations. During the first deep drilling, there may not be enough information about the drilled horizons. If the reservoir pressure in the production horizon is higher than the hydrostatic pressure of the fluid in the well (for example, drilling mud), the formation fluids flow into the well and move towards the surface, which causes open eruption. The rig personnel must be properly trained to be able to recognize the occurrence of rising pressure by various signs and to respond effectively to the situation. Sometimes, under the influence of the human factor or equipment failure, open eruption still occurs. The article discusses the possibilities of eliminating open eruptions with drilling tools
DNA Replication Timing Is Maintained Genome-Wide in Primary Human Myoblasts Independent of D4Z4 Contraction in FSH Muscular Dystrophy
Facioscapulohumeral muscular dystrophy (FSHD) is linked to contraction of an array of tandem 3.3-kb repeats (D4Z4) at 4q35.2 from 11-100 copies to 1-10 copies. The extent to which D4Z4 contraction at 4q35.2 affects overall 4q35.2 chromatin organization remains unclear. Because DNA replication timing is highly predictive of long-range chromatin interactions, we generated genome-wide replication-timing profiles for FSHD and control myogenic precursor cells. We compared non-immortalized myoblasts from four FSHD patients and three control individuals to each other and to a variety of other human cell types. This study also represents the first genome-wide comparison of replication timing profiles in non-immortalized human cell cultures. Myoblasts from both control and FSHD individuals all shared a myoblast-specific replication profile. In contrast, male and female individuals were readily distinguished by monoallelic differences in replication timing at DXZ4 and other regions across the X chromosome affected by X inactivation. We conclude that replication timing is a robust cell-type specific feature that is unaffected by FSHD-related D4Z4 contraction
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