In the context of hydraulic fracturing, microseismic events are basically very small earthquakes characterized by generally negative moment magnitude. With the increased interest in induced seismicity and human-caused earthquakes associated with shale gas and heavy oil plays, and related activities associated with injection practices, a significant increase in microseismic monitoring has been reported in Canada, the United States, Eastern Europe, and the United Kingdom. The quantitative measure of an earthquake's size at its source is its magnitude. The severity of an earthquake can be expressed in terms of intensity and magnitude. Developed in the 1970s to succeed the 1930s-era Richter magnitude scale, the moment magnitude scale is used by seismologists to measure the size of earthquakes. Historically, anthropogenic-induced earthquakes have been documented for such activities as reservoir impoundment, fluid injection, fluid extraction, mining, and construction.
Oligonucleotide structural information can be obtained by observing heat-induced changes in UV absorption at wavelengths above 280 nm.The experimental method is simple, requiring two absorption measurements on the same sample, which are used to calculate the percentage hyperchromicity for the helix to coil conversion Y>,, (where Yx = 100[(EX, at T20C)/(E, at T1 °C)] -100; T1 and T2 are temperatures at which essentially all molecules of the oligomer are in their structured form or in their random coil form, respectively).We find that, at long wavelengths, Yx is very sensitive to the type of stacking present in the structured form of the oligonucleotide; for example, the B-helical form of the duplex d(CGCGCG) has a strong positive
Introduction: Proton pump inhibitors (PPI) are amongst the most widely prescribed classes of medication in the United States, commonly prescribed by primary care providers and specialists from a variety of disciplines. Indications for the initiation and maintenance of PPI therapy are well established. However, because they are so widely prescribed, responsibility for the management of PPIs is often diffused over numerous providers. This study evaluated the rates of PPI de-escalation in patients receiving PPIs from GI versus non-GI prescribers. Methods: A retrospective chart review of randomly selected medical records during a 1 year period of patients on >6 months PPI therapy seen by a faculty gastroenterologist at an urban university medical center was conducted. Data was collected regarding the indication, length, and prescriber of PPIs and whether there was a documented PPI de-escalation discussion. De-escalation was defined as attempts at reduction in dose, reduction in frequency, or complete PPI discontinuation. Patients prescribed PPIs for Barrett's esophagus or gastrointestinal bleeding were excluded. A Microsoft Excel database maintaining subject confidentiality was used. Statistical analysis was conducted using a two-tailed Fisher's Exact Test with significance set at p < 0.05. Results: A total of 600 charts were initially reviewed, of which, 324 were included in the analysis. PPIs were primarily prescribed by GI providers in 141 patients and non-GI providers in 183 patients. Of the 141 patients prescribed PPIs by their GI provider, 41 (29%) had an attempt to de-escalate therapy. Of the 183 patients prescribed PPIs by a non-GI provider, 25 (16%) had a de-escalation discussion. There was a significant increase in documented attempts at PPI de-escalation in patients whose PPIs were primarily prescribed by GI providers versus non-GI providers (p=0.0008). Conclusion: PPIs are highly effective, safe, and commonly prescribed. However, these medications are not without risks and there is evidence to suggest that patients with uncomplicated GERD who have obtained symptomatic relief with PPIs, should undergo attempts at de-escalation of therapy. Our data suggest that gastroenterologists are more likely to have a discussion about PPI de-escalation if the patient's primary PPI prescriber is a GI provider as compared to a non-GI provider (29% vs 16%, p = 0.0008). Increased efforts at PPI de-escalation should be made in all patients if appropriate.
Pneumocystis carinii is a mammalian pathogen that contains a self-splicing group I intron in its large subunit rRNA precursor. We report the binding of methylphosphonate/DNA chimeras and neutral methylphosphonate oligonucleotides to a ribozyme that is a truncated form of the intron. At 15 mM Mg2+, the nuclease-resistant all-methylphosphonate hexamer, d(AmTmGmAmCm)rU, with a sequence that mimics the 3' end of the precursor's 5' exon, binds with a dissociation constant of 272 nM. The hexamer's dissociation constant for binding by base-pairing alone to the ribozyme's binding site sequence is 8.3 mM. Thus there is a 30 000-fold binding enhancement by tertiary interactions (BETI), which is close to the 60 000-fold enhancement previously observed with the all-ribo hexamer, r(AUGACU). Evidently, backbone charge and 2' hydroxyl groups are not required for BETI. At 3−15 mM Mg2+, the all-methylphosphonate and DNA oligonucleotides trans-splice to a truncated form of the rRNA precursor, but do not compete with cis-splicing when pG is present. These results suggest that uncharged or partially charged backbones may be used to design therapeutics to target RNAs through binding enhancement by tertiary interactions and suicide inhibition strategies.
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