31 research outputs found

    Design and Applications of Multi-Frequency Holographic Subsurface Radar: Review and Case Histories

    Get PDF
    Holographic subsurface radar (HSR) is not currently in widespread usage. This is due to a historical perspective in the ground-penetrating radar (GPR) community that the high attenuation of electromagnetic waves in most media of interest and the inability to apply time-varying gain to the continuous-wave (CW) HSR signal preclude sufficient effective penetration depth. While it is true that the fundamental physics of HSR, with its use of a CW signal, does not allow amplification of later (i.e., deeper) arrivals in lossy media (as is possible with impulse subsurface radar (ISR)), HSR has distinct advantages. The most important of these is the ability to do shallow subsurface imaging with a resolution that is not possible with ISR. In addition, the design of an HSR system is simpler than for ISR due to the relatively low-tech transmitting and receiving antennae. This paper provides a review of the main principles of HSR through an optical analogy and describes possible algorithms for radar hologram reconstruction. We also present a review of the history of development of systems and applications of the RASCAN type, which is possibly the only commercially available holographic subsurface radar. Among the subsurface imaging and remote sensing applications considered are humanitarian demining, construction inspection, nondestructive testing of dielectric aerospace materials, surveys of historic architecture and artworks, paleontology, and security screening. Each application is illustrated with relevant data acquired in laboratory and/or field experiments

    Neo-generation of neogenetic bullae after surgery for spontaneous pneumothorax in young adults: a prospective study

    No full text
    Abstract Background To investigate the development of neogenetic bullae or blebs on 1-year postoperative chest computed tomography after video-assisted thoracic surgery (VATS) in young patients with primary spontaneous pneumothorax (PSP). Methods In this prospective study, 10- to 20-year-old patients with PSP were treated via VATS with additional procedures (bullectomy, cold coagulation, coverage, pleural abrasion, or chemical pleurodesis). All patients underwent the additional procedures and computed tomography of the chest 1 year postoperatively for the assessment of neogenetic bullae. Postoperative PSP recurrence was monitored, and recurrence-free survival was evaluated using Kaplan-Meier analysis. Results Fifty-seven patients (66 cases) aged 17 ± 2 years underwent VATS for PSP and were followed up for 938 ± 496 days. Of the 36 cases at 1-year follow-up, 23 (63.9%) showed neogenetic bullae, which were adjacent to the staple lines in 16 cases (69.6%). The 1- and 2-year recurrence-free survival rates were 88.9 and 85.1%, respectively. Nine of the 66 cases (13.6%) showed recurrence after 869 ± 542 days. A history of contralateral PSP was significantly associated with recurrence. Conclusions VATS, combined with additional procedures, provides acceptable long-term results in young patients with PSP. Additional procedures reduce the recurrence rate of PSP but do not prevent the occurrence of neogenetic bullae. A history of contralateral PSP is a potential risk factor for post-VATS recurrence in young patients

    Invasive Thymoma with Pure Red Cell Aplasia and Amegakaryocytic Thrombocytopenia

    No full text
    We here describe a case involving a 67-yearold female patient who was referred to our hospital due to severe anemia (hemoglobin, 5.0 g/dL), thrombocytopenia (platelet count, 0.6 × 104/μL), and a mediastinal shadow with calcification noted on X-ray. On admission, an anterior mediastinal tumor was detected, and bone marrow biopsy revealed few megakaryocytes and severely reduced numbers of erythroid cells. The diagnosis was thymoma with pure red cell aplasia (PRCA) and acquired amegakaryocytic thrombocytopenia (AAMT). On Day 8 of admission, the patient received immunosuppressive therapy together with cyclosporine for the 2 severe hematologic diseases, which were stabilized within 2 months. Subsequently, total thymectomy was performed. The diagnosis of the tumor invading the left lung was invasive thymoma, Masaoka- Koga stage III. The histological diagnosis was World Health Organization type AB. Thymoma accompanied with PRCA and AAMT is very rare, and, based on our case, immunotherapeutic therapy for the hematologic disorders should precede surgical intervention

    Dietary Fat-Accelerating Leptin Signaling Promotes Protumorigenic Gastric Environment in Mice

    No full text
    Excess of fat intake leads to obesity and causes a variety of metabolic diseases and cancer. We previously demonstrated that high-lard diet induces intestinal metaplasia, a precancerous lesion of the stomach mediated by leptin signaling. This study aims to investigate which kinds of dietary fat cause the intestinal metaplasia onset. We fed eight kinds of high-fat diets (HFDs) of animal or plant origin to mice evaluated their effect on gastric pathogenesis. Five types of dietary fat were divided according to their observed effects: Obese with high metaplasia (group I; beef tallow, lard, and hydrogenated coconut oil), non-obese with high metaplasia (group II; linseed oil), obese without metaplasia (group III; corn oil and olive oil), non-obese without metaplasia (group IV, soybean oil) and lean without metaplasia (group V; cocoa butter). The group I and II diets induced leptin, phosphorylated leptin receptor (ObR), signal transducer and activator 3 (STAT3), and increased intracellular β-catenin accumulation in the stomach. Moreover, mice fed these HFDs with 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), a gastric carcinogen, and further accelerated dysplasia in the stomach. Lactobacillus occupancy in the stomach increased in all HFDs except hydrogenated coconut oil. Our findings suggest that HFDs inducing leptin signaling accelerate the enhancement of protumorigenic gastric microenvironment independent of body mass gain or microbiome changes

    腎移植における Ureteroneocystostomy の問題点 : Intravesical UreteroneocystostomyとExtravesical Ureteroneocystostomy の比較

    Get PDF
    The authors have made extensive studies of ureteroneocystostomies, that are intravesical and extravesical methods, and postoperative urological complications on 58 cases of living related renal transplants and 12 cases of cadaveric renal transplants at the Second Department of Surgery, Hiroshima University School of Medicine. Among the 21 cases in whom intravesical ureteroneocystostomy was employed, there was one case of urinary fistula. Among the 49 cases in whom extravesical ureteroneocystostomy was employed, two case of postoperative bleeding, a case of stenosis of the ureter and a case of urinary fistula of the anastomosis were observed. There was one case of graft loss in each method, but no case died. The incidence of complications is low on both methods. But extravesical ureteroneocystostomy does not require a large incision of the vesical wall and is advantageous in having a possibility to conduct the submucosal tunnel visually and a easy doing of anastomosis between the ureter and the vesical mucosa. Then, the procedure of our modified extravesical ureteroneocytostomy was reported
    corecore