4.5-/4.9-GHz-Band Selective High-Efficiency GaN HEMT Power Amplifier by Characteristic Impedance Switching

A 4.5-/4.9-GHz band-selective GaN HEMT high-efficiency power amplifier has been designed and evaluated for next-generation wireless communication systems. An optimum termination impedance for each high-efficiency operation band was changed by using PIN diodes inserted into a harmonic treatment circuit at the output side. In order to minimize the influence of the insertion loss of the PIN diodes, an additional line is arranged in parallel with the open-ended stub used for second harmonic treatment, and the line and stub are connected with the PIN diodes to change the effective characteristic impedance. The fabricated GaN HEMT amplifier achieved a maximum power-added efficiency of 57% and 66% and a maximum drain efficiency of 62% and 70% at 4.6 and 5.0GHz, respectively, with a saturated output power of 38dBm, for each switched condition

Lubiprostone Increases Small Intestinal Smooth Muscle Contractions Through a Prostaglandin E Receptor 1 (EP1)-mediated Pathway

Background/Aims Lubiprostone, a chloride channel type 2 (ClC-2) activator, was thought to treat constipation by enhancing intestinal secretion. It has been associated with increased intestinal transit and delayed gastric emptying. Structurally similar to prostones with up to 54% prostaglandin E2 activity on prostaglandin E receptor 1 (EP1), lubiprostone may also exert EP1-mediated procontractile effect on intestinal smooth muscles. We investigated lubiprostone's effects on intestinal smooth muscle contractions and pyloric sphincter tone. Methods: Isolated murine small intestinal (longitudinal and circular) and pyloric tissues were mounted in organ baths with modified Krebs solution for isometric recording. Basal muscle tension and response to electrical field stimulation (EFS; 2 ms pulses/10 V/6 Hz/30 sec train) were measured with lubiprostone (10-10-10-5 M) ± EP1 antagonist. Significance was established using Student t test and P < 0.05. Results: Lubiprostone had no effect on the basal tension or EFS-induced contractions of longitudinal muscles. With circular muscles, lubiprostone caused a dose-dependent increase in EFS-induced contractions (2.11 ± 0.88 to 4.43 ± 1.38 N/g, P = 0.020) that was inhibited by pretreatment with EP1 antagonist (1.69 ± 0.70 vs. 4.43 ± 1.38 N/g, P = 0.030). Lubiprostone had no effect on circular muscle basal tension, but it induced a dose-dependent increase in pyloric basal tone (1.07 ± 0.01 to 1.97 ± 0.86 fold increase, P < 0.05) that was inhibited by EP1 antagonist. Conclusions: In mice, lubiprostone caused a dose-dependent and EP1-mediated increase in contractility of circular but not longitudinal small intestinal smooth muscles, and in basal tone of the pylorus. These findings suggest another mechanism for lubiprostone's observed clinical effects on gastrointestinal motility

Stretta Radiofrequency Treatment for GERD: A Safe and Effective Modality

Gastroesophageal reflux disease is one of the leading gastrointestinal disorders. Current treatments include lifestyle modifications, pharmacological therapies, surgical fundoplications, and, more recently, endoscopic procedures. The rising concern of long-term side effects of the popular proton-pump inhibitors and the more recent evidence raising doubts about the durability of fundoplication have spurred reinterest in endoscopic procedures to treat reflux disorders. In the aftermath of several innovative antireflux procedures that were introduced and failed clinically or financially over the past decade, there is lingering confusion regarding the merits of the presently available interventions. This paper focuses on one endoscopic procedure, Stretta, which now enjoys the longest experience, a recent meta-analysis, and robust data supporting its safety, efficacy, and durability. Stretta reduces esophageal acid exposure, decreases the frequency of transient lower esophageal relaxation, increases patient satisfaction, decreases medication use, and improves quality of life. As such, this procedure remains a valuable nonsurgical treatment option in the management of gastroesophageal reflux disease

Homogeneous minimal submanifolds in spheres

Thesis--University of Tsukuba, D.Sc.(B), no. 280, 1985. 10. 3

Degree of the standard isometric minimal immersions of complex projective spaces into spheres

Let (Mm, g) be an irreducible symmetric space of compact type, and △ be the Laplace-Beltrami operator of (M, g) acting on C∞ functions. We denote by [?]k the k-th eigen-value of △1 0=[?]0<[?]1<･･･, and by Vk the corresponding ..

Embryological evidence substantiates the subcoxal theory on the origin of pleuron in insects

The lateral body plate pleuron is a significant structure in insects that contributes to the development and elaboration of wings and limbs (appendages). Although the pleuron is thought to originate from the proximal-most appendicular segment, the subcoxa, details remain unclear, and the morphological boundary between the dorsal body plate tergum and appendage (BTA) has not been clearly specified. Employing low-vacuum scanning electron microscopy (SEM) and the nano-suit method for SEM, we followed, in detail, the development of the thoracic segments of the two-spotted cricket Gryllus bimaculatus and succeeded in clearly defining the BTA. This study demonstrates the subcoxal origin of the pleuron, suggests the tergal origin of spiracles, and reveals that the wing proper originates exclusively from the tergum, whereas the wing hinge and direct muscles may be appendicular in origin, suggesting the dual origin (i.e., tergal plus appendicular origin) of wings