From numerical solutions of a gyrokinetic model for ion temperature gradient turbulence it is shown that nonlinear coupling is dominated by three-wave interactions that include spectral components of ...the zonal flow and damped subdominant modes. Zonal flows dissipate very little energy injected by the instability, but facilitate its transfer from the unstable mode to dissipative subdominant modes, in part due to the small frequency sum of such triplets. Although energy is transferred to higher wave numbers, consistent with shearing, a large fraction is transferred to damped subdominant modes within the instability range. This is a new aspect of regulation of turbulence by zonal flows.
Using a combination of iterative structure-based design and an analysis of oral pharmacokinetics and antiviral activity, AG1343 (Viracept, nelfinavir mesylate), a nonpeptidic inhibitor of HIV-1 ...protease, was identified. AG1343 is a potent enzyme inhibitor (K i = 2 nM) and antiviral agent (HIV-1 ED50 = 14 nM). An X-ray cocrystal structure of the enzyme−AG1343 complex reveals how the novel thiophenyl ether and phenol−amide substituents of the inhibitor interact with the S1 and S2 subsites of HIV-1 protease, respectively. In vivo studies indicate that AG1343 is well absorbed orally in a variety of species and possesses favorable pharmacokinetic properties in humans. AG1343 (Viracept) has recently been approved for marketing for the treatment of AIDS.
Tumors of the Esophagus Hatch, George F.; Wertheimer‐Hatch, Laura; Hatch, Kathryn F. ...
World journal of surgery,
April 2000, 2000-Apr, 2000-04-00, 20000401, Letnik:
24, Številka:
4
Journal Article
Recenzirano
.
This collective review includes all available case reports of smooth muscle (stromal) tumors of the esophagus in the world literature. Compiling this review, we endeavored to examine cumulative and ...recently collected data of both benign and malignant esophageal smooth muscle tumors found in the literature spanning the period from 1875 to 1996, which totaled 1679 leiomyomas (LMs) and 165 leiomyosarcomas (LMSs). The peak age of occurrence of benign smooth muscle tumors in the esophagus was found to be between the ages of 30 and 59, whereas the highest frequency of malignant tumors was seen later in life, during the decade from age 60 to 69. The most common location of both LMs and LMSs was the lower third of the esophagus. Their patterns of growth differed; LMs were more likely to grow intramurally, and LMSs were predominantly intraluminal. Most patients with LMs presented with dysphagia and pain or discomfort; patients with LMSs additionally commonly complained of weight loss. As with smooth muscle tumors of other areas of the gastrointestinal tract, the duration of symptoms averaged 1 month to 1 year, and malignant tumors grew to larger sizes than benign neoplasms. Approximately one‐third of LMSs had metastasized at diagnosis, and there was a 5‐year survival rate of approximately 20%.
Tumors of the Small Intestine Blanchard, D. Kay; Budde, Jason M.; Hatch, George F. ...
World journal of surgery,
April 2000, 2000-Apr, 2000-04-00, 20000401, Letnik:
24, Številka:
4
Journal Article
Recenzirano
.
This collective review includes all available case reports and series of smooth muscle (stromal) tumors of the small intestine in the world literature from 1881 to 1996. We identified 1074 patients ...with leiomyoma (LM) and 1689 with leiomyosarcoma (LMS). Our purpose was to update our previous review, which encompassed case reports and series from 1881 to 1959, which included 350 LMs and 257 LMSs. The peak incidence of smooth muscle tumors in the small intestine in both male and female patients was between the ages of 50 and 59. Most commonly, the presenting complaint was gastrointestinal bleeding. Computed tomography was found to detect LM and LMS most successfully and had the additional advantage of locating metastatic disease. The jejunum contained the highest numbers of smooth muscle tumors, followed by the ileum and then the duodenum, with malignant lesions in all locations typically attaining larger diameters than benign tumors. The overall rate of metastatic spread of LMS ranged from 24% to 50%, with the liver being most commonly involved. Unlike other sarcomas, both hematogenous and lymphatic spread were common. The 5‐year survival of 705 patients with LMS from 22 series was 27.8%. For both benign and malignant smooth muscle tumors of the small intestine, surgery remains the treatment of choice, with little efficacy reported for irradiation, chemotherapy, or both.
Peatland environments provide important ecosystem services including water and carbon storage, nutrient processing and retention, and wildlife habitat. However, these systems and the services they ...provide have been degraded through historical anthropogenic agricultural conversion and dewatering practices. Effective wetland restoration requires incorporating site hydrology and understanding groundwater discharge spatial patterns. Groundwater discharge maintains wetland ecosystems by providing relatively stable hydrologic conditions, nutrient inputs, and thermal buffering important for ecological structure and function; however, a comprehensive site-specific evaluation is rarely feasible for such resource-constrained projects. An improved process-based understanding of groundwater discharge in peatlands may help guide ecological restoration design without the need for invasive methodologies and detailed site-specific investigation. Here we examine a kettle-hole peatland in southeast Massachusetts historically modified for commercial cranberry farming. During the time of our investigation, a large process-based ecological restoration project was in the assessment and design phases. To gain insight into the drivers of site hydrology, we evaluated the spatial patterning of groundwater discharge and the subsurface structure of the peatland complex using heat-tracing methods and ground-penetrating radar. Our results illustrate that two groundwater discharge processes contribute to the peatland hydrologic system: diffuse lower-flux marginal matrix seepage and discrete higher-flux preferential-flow-path seepage. Both types of groundwater discharge develop through interactions with subsurface peatland basin structure, often where the basin slope is at a high angle to the regional groundwater gradient. These field observations indicate strong correlation between subsurface structures and surficial groundwater discharge. Understanding these general patterns may allow resource managers to more efficiently predict and locate groundwater seepage, confirm these using remote sensing technologies, and incorporate this information into restoration design for these critical ecosystems.
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