Search

Electromagnetic properties of conventional radar absorbing materials (RAM) make it difficult to use them to provide remarkable surface electromagnetic waves (SEMW) attenuation with thin thickness at low radar frequencies such as in the UHF and L bands. In this paper, a composite structure realized by a grounded RAM slab covered by a resistive sheet is proposed. The use of a resistive sheet results in a significant increase of SEMW attenuation performance at low frequency, but almost no increase in its thickness. The electromagnetic scattering properties for a target coated with the RAM with/without covered by a resistive sheet are considered for interpreting the improvement of SEMW attenuation with resistive loading. Using a method-of-moments (MoM) computational scheme, we explore the performance of the proposed composite structure as radar backscattering suppression for a metal slab at low radar frequencies. It is found that the RAM with resistive loading has significantly increased SEMW attenuation at low frequencies, and advances the large incidence angle or grazing angle mono-static radar cross section (RCS) reduction of the coating slab further than the RAM without resistive loading case. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical features, surgical effects and factors that may affect prognosis of muscular invasive bladder cancer in young people. Methods: The clinical data of young (aged 44 and below) patients with muscle invasive bladder cancer who underwent robot-assisted radical cystectomy at the First Affiliated Hospital of Zhengzhou University from October 1st, 2014 to October 31st, 2018 were retrospectively analyzed, which included age, gender, body mass index (BMI), tumor discovery method, tumor location, tumor size, comorbid diseases, operation time, intraoperative blood loss, urinary diversion method, postoperative complications, postoperative hospital stay, postoperative pathology and follow-up results. Results: A total of 24 patients were enrolled in this study, and 18(75%) were male and 6(25%) were female. The age was (40.4±3.5) years and the BMI was (24.7±2.5) kg/m 2 . At initial visit, there were 19(79%) patients who presented with hematuria, 4 (17%) with lower urinary tract symptoms, and 1(4%) was discovered by routine examination. Fifteen (62%) patients had single tumor, and 9(38%) had multiple tumors. The tumor diameter of 14(58%) patients were ≥3 cm and 3(13%) patients were combined with hydronephrosis. All patients received robot-assisted radical cystectomy successfully. The operative time was (325.8±57.2) min, and the blood loss during operation was 200(162,300) ml. The duration of postoperative hospital stay was 11(9,22) days. And according to different urinary diversion methods, 17(80%) patients had ileal orthotopic neobladder and 7(20%) had ileal conduit. For patients whose sexual nerves were preserved, 6(6/9) recovered their sexual function after one year of the surgery. The final pathological results showed that 16(67%) patients were in T2 stage, 7(29%) patients were in T3 stage and that 1(4%) patient in T4 stage. There were 6 (25%) patients with lymphatic metastasis, 8(33%) with low-grade papillary urothelial carcinoma, 14(58%) with high-grade papillary urothelial carcinoma, 1(4%) with adenocarcinoma and 1(4%) with small cell neuroendocrine carcinoma. Early complications of the patients were mostly slight, and only 2(8%) patients had Clavien Ⅲdegree complications, while few patients had late complications. The follow-up time was (26±12) months. During the follow-up time, there was 1(4%) patient who died because of liver and kidney failure. Distant metastasis occurred in 4(17%) cases and 1(4%) patient had urothelial carcinoma on one side of the ureter. Lymphatic metastasis ( P =0.018) and ≥ T3 ( P =0.038) stage were associated with the prognosis. Conclusions: For young patients with muscular invasive bladder cancer, the major initial presentation is hematuria, and most of them have advanced tumor stage and high malignant degree. Robot-assisted radical cystectomy is a safe and effective operation method with less postoperative complications, and protecting sexual nerve contributes to the recovery of sexual function. Advanced tumor stage (≥T3) and lymphatic metastasis are associated with distant metastasis and recurrence.

Nerve growth factor (NGF) exerts both stimulatory and inhibitory effects on neuronal and certain nonneuronal tumors with the effect based on the type of tumor. We investigated NGF and its receptors (TrkA and p75) in pancreatic cancer cells (PANC-1, MIA-PaCa-2, CAPAN-1, ASPC-1, and T3M4) by reverse transcription-PCR, Western blot analysis, NGF ELISA, and growth assays. NGF mRNA was present at comparable levels in all five pancreatic cancer cell lines. TrkA expression was relatively high in PANC-1 and MIA-PaCa-2 cells and low in CAPAN-1, ASPC-1, and T3M4 cells. p75 expression was high in PANC-1, MIA-PaCa-2, and T3M4 cells, moderate in CAPAN-1, and low in ASPC-1 cells. By ELISA assay, the intracellular NGF content in all cell lines was approximately 40 pg/10(6) cells. NGF content increased significantly in PANC-1 and MIA-PaCa-2 cells when these cells were cultured with serum-free media, whereas there was no change in the other cancer cell lines. PANC-1 and MIA-PaCa-2 cells but not the other cell lines released NGF in the culture media. Exogenous NGF stimulated the growth of PANC-1 and MIA-PaCa-2 cells, inhibited the growth of T3M4 and CAPAN-1 cells in a dose- and time-dependent manner, and did not affect the growth of ASPC-1 cells. NGF led to the phosphorylation of TrkA, mitogen-activated protein kinase (MAPK), and p38 MAPK but not stress-activated protein kinase/c-Jun NH2-terminal kinase in PANC-1 and MIA-PaCa-2 cells. In contrast, in the other pancreatic cancer cell lines none of these kinases were phosphorylated by NGF. In conclusion, the effects of NGF on pancreatic cancer cell growth are dependent on the expression levels and the balance of its TrkA and p75 receptors. NGF-induced pancreatic cancer cell growth seems to be mediated through the phosphorylation of TrkA and subsequently via MAPK. These results point to a previously unknown autocrine/paracrine pathway in pancreatic cancer, suggesting that NGF-TrkA interactions are important factors influencing cell growth and spread in this malignancy.

Objective: To study the mechanisms that are involved in nerve growth and contribute to pain generation in chronic pancreatitis (CP)., Summary Background Data: Chronic pancreatitis is a painful disease associated with characteristic nerve changes, including an increase in nerve number and diameter. The mechanisms that influence nerve growth are not known. Nerve growth factor (NGF) and its high-affinity tyrosine kinase receptor A (TrkA) are involved in neural development and survival and growth of central and peripheral nerves., Methods: Nerve growth factor and TrkA were investigated by Northern blot analysis, in situ hybridization, and immunohistochemical staining in the pancreases of 24 patients with CP, and the findings were correlated with clinical parameters., Results: By Northern blot analysis, NGF and TrkA mRNA expression were increased in 42% (13.1-fold) and 54% (5.5-fold) of the CP samples (p < 0.01), respectively. In situ hybridization revealed that in CP, enhanced NGF mRNA expression was present in metaplastic ductal cells, in degenerating acinar cells, and in acinar cells dedifferentiating into tubular structures. TrkA mRNA was intensely present in the perineurium. Further, enhanced NGF and TrkA mRNA signals were also present in intrapancreatic ganglia cells in CP samples. Immunohistochemistry confirmed the in situ hybridization findings. Analysis of the molecular findings with clinical parameters revealed a significant relation (p < 0.05) between NGF mRNA levels and pancreatic fibrosis (r = 0.64) and acinar cell damage (r = 0.74) and between TrkA mRNA and pain intensity (r = 0.84)., Conclusion: Activation of the NGF/TrkA pathway occurs in CP. It might influence neural morphologic changes and the pain syndrome in this disorder.