86 research outputs found
Applied Hydrological Modeling with the Use of Geoinformatics: Theory and Practice
Water resource management and catchment analysis are crucial aspects of the twenty-first century in hydrological and environmental sciences. Linked directly with studies and research about climate change effects in global resources (e.g., diminution of rainfall dynamic), as well as continuously growing extreme natural phenomena with catastrophic results (e.g., floods and erosion), hydrological modeling has become a key priority in modern academic research goals. On a national or lower administrative level, the need for coping with natural disasters—affecting mainly human life, property, local economy, infrastructure, etc.—and the need to design management plans and projects for sustainable exploitation of natural resources set hydrological modeling in high demand by government organizations and local authorities. Thus, hazard assessment and risk evaluation modeling have become a strategic aim and an extremely useful tool for stakeholders, decision-makers, and scientific community
Ventricular Pace Suppression Function: Prophylaxing from Iatrogenic Dyssynchrony
A patient with an implanted dual-chamber pacemaker (DDDR) for sick sinus syndrome had a pulse generator exchange due to battery depletion. Apropos with the procedure, it was noted that the patient had continuous ventricular pacing via a pacing lead located at the right ventricular apex. In order to avoid possible deleterious effects of the iatrogenic dyssynchrony conferred by this kind of pacing, the algorithm of ventricular pace suppression function was activated in the new device that practically led to functional AAI pacing, deemed a more physiologic mode of pacing that could prevent the potential harmful effects of right ventricular apical pacing. Rhythmos 2018;13(3):59-61
The impact of stress on tumor growth: peripheral CRF mediates tumor-promoting effects of stress
<p>Abstract</p> <p>Introduction</p> <p>Stress has been shown to be a tumor promoting factor. Both clinical and laboratory studies have shown that chronic stress is associated with tumor growth in several types of cancer. Corticotropin Releasing Factor (CRF) is the major hypothalamic mediator of stress, but is also expressed in peripheral tissues. Earlier studies have shown that peripheral CRF affects breast cancer cell proliferation and motility. The aim of the present study was to assess the significance of peripheral CRF on tumor growth as a mediator of the response to stress in vivo.</p> <p>Methods</p> <p>For this purpose we used the 4T1 breast cancer cell line in cell culture and in vivo. Cells were treated with CRF in culture and gene specific arrays were performed to identify genes directly affected by CRF and involved in breast cancer cell growth. To assess the impact of peripheral CRF as a stress mediator in tumor growth, Balb/c mice were orthotopically injected with 4T1 cells in the mammary fat pad to induce breast tumors. Mice were subjected to repetitive immobilization stress as a model of chronic stress. To inhibit the action of CRF, the CRF antagonist antalarmin was injected intraperitoneally. Breast tissue samples were histologically analyzed and assessed for neoangiogenesis.</p> <p>Results</p> <p>Array analysis revealed among other genes that CRF induced the expression of SMAD2 and β-catenin, genes involved in breast cancer cell proliferation and cytoskeletal changes associated with metastasis. Cell transfection and luciferase assays confirmed the role of CRF in WNT- β-catenin signaling. CRF induced 4T1 cell proliferation and augmented the TGF-β action on proliferation confirming its impact on TGFβ/SMAD2 signaling. In addition, CRF promoted actin reorganization and cell migration, suggesting a direct tumor-promoting action. Chronic stress augmented tumor growth in 4T1 breast tumor bearing mice and peripheral administration of the CRF antagonist antalarmin suppressed this effect. Moreover, antalarmin suppressed neoangiogenesis in 4T1 tumors in vivo.</p> <p>Conclusion</p> <p>This is the first report demonstrating that peripheral CRF, at least in part, mediates the tumor-promoting effects of stress and implicates CRF in SMAD2 and β-catenin expression.</p
Toxins and Secretion Systems of Photorhabdus luminescens
Photorhabdus luminescens is a nematode-symbiotic, gram negative, bioluminescent bacterium, belonging to the family of Enterobacteriaceae. Recent studies show the importance of this bacterium as an alternative source of insecticides, as well as an emerging human pathogen. Various toxins have been identified and characterized in this bacterium. These toxins are classified into four major groups: the toxin complexes (Tcs), the Photorhabdus insect related (Pir) proteins, the “makes caterpillars floppy” (Mcf) toxins and the Photorhabdus virulence cassettes (PVC); the mechanisms however of toxin secretion are not fully elucidated. Using bioinformatics analysis and comparison against the components of known secretion systems, multiple copies of components of all known secretion systems, except the ones composing a type IV secretion system, were identified throughout the entire genome of the bacterium. This indicates that Photorhabdus luminescens has all the necessary means for the secretion of virulence factors, thus it is capable of establishing a microbial infection
Lateral Gene Expression in Drosophila Early Embryos Is Supported by Grainyhead-Mediated Activation and Tiers of Dorsally-Localized Repression
The general consensus in the field is that limiting amounts of the transcription factor Dorsal establish dorsal boundaries of genes expressed along the dorsal-ventral (DV) axis of early Drosophila embryos, while repressors establish ventral boundaries. Yet recent studies have provided evidence that repressors act to specify the dorsal boundary of intermediate neuroblasts defective (ind), a gene expressed in a stripe along the DV axis in lateral regions of the embryo. Here we show that a short 12 base pair sequence (“the A-box”) present twice within the ind CRM is both necessary and sufficient to support transcriptional repression in dorsal regions of embryos. To identify binding factors, we conducted affinity chromatography using the A-box element and found a number of DNA-binding proteins and chromatin-associated factors using mass spectroscopy. Only Grainyhead (Grh), a CP2 transcription factor with a unique DNA-binding domain, was found to bind the A-box sequence. Our results suggest that Grh acts as an activator to support expression of ind, which was surprising as we identified this factor using an element that mediates dorsally-localized repression. Grh and Dorsal both contribute to ind transcriptional activation. However, another recent study found that the repressor Capicua (Cic) also binds to the A-box sequence. While Cic was not identified through our A-box affinity chromatography, utilization of the same site, the A-box, by both factors Grh (activator) and Cic (repressor) may also support a “switch-like” response that helps to sharpen the ind dorsal boundary. Furthermore, our results also demonstrate that TGF-β signaling acts to refine ind CRM expression in an A-box independent manner in dorsal-most regions, suggesting that tiers of repression act in dorsal regions of the embryo
Sequential treatment with teriparatide and strontium ranelate in a postmenopausal woman with atypical femoral fractures after long-term bisphosphonate administration
AbstrAct ObJEctIVE: Despite the existence of numerous case series, no evidenced-based medical management for atypical fractures associated with bisphosphonate (bP) treatment has been established. DEsIGN: We report the outcome of teriparatide (trP) administration followed by strontium ranelate (sr) in a woman with a complete and an incomplete contralateral atypical fracture of the femoral diaphysis (AFF) associated with bP treatment. the spontaneous complete AFF was managed with intramedullary nailing, discontinuation of bP and initiation trP. rEsULts: Eleven months later, she suffered a contralateral incomplete AFF. At the completion of the trP treatment, she had only slight discomfort in the femur with the incomplete AFF. bMD testing revealed increase of 7.61% at the lumbar spine (Ls) and 0.8% at the hip. Following trP, 1-year sr treatment resulted in further bMD increase of 9.2% at the Ls and 1.4% in the hip, while she does not report any pain. bone markers remain within the normal range. cONcLUsION: Our case indicates that sequential therapy with trP and sr in cases of AFF might be a rational treatment option. However, there is a need for additional information concerning the effect of trP and sr, given alone or sequentially, in these patients in order to incorporate these drugs into the management of AFF
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Evaluation of urban local-scale aerodynamic parameters: implications for the vertical profile of wind speed and for source areas
Nine methods to determine local-scale aerodynamic roughness length (z0) and zero-plane displacement (zd) are compared at three sites (within 60 m of each other) in London, UK. Methods include three anemometric (single-level high frequency observations), six morphometric (surface geometry) and one reference-based approach (look-up tables). A footprint model is used with the morphometric methods in an iterative procedure. The results are insensitive to the initial zd and z0 estimates. Across the three sites, zd varies between 5 – 45 m depending upon the method used. Morphometric methods that incorporate roughness-element height variability agree better with anemometric methods, indicating zd is consistently greater than the local mean building height. Depending upon method and wind direction, z0 varies between 0.1 and 5 m with morphometric z0 consistently being 2 – 3 m larger than the anemometric z0. No morphometric method consistently resembles the anemometric methods. Wind-speed profiles observed with Doppler lidar provide additional data with which to assess the methods. Locally determined roughness parameters are used to extrapolate wind-speed profiles to a height roughly 200 m above the canopy. Wind-speed profiles extrapolated based on morphometric methods that account for roughness-element height variability are most similar to observations. The extent of the modelled source area for measurements varies by up to a factor of three, depending upon the morphometric method used to determine zd and z0
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