3,453 research outputs found
Ultrasmall Dual-Band Metamaterial Antennas Based on Asymmetrical Hybrid Resonators
A new type of hybrid resonant circuit model is investigated theoretically and experimentally. The resonant model consists of a right hand (RH) patch part and a composite right and left handed (CRLH) part (RH + CRLH), which determines a compact size and also a convenient frequency modulation characteristic for the proposed antennas. For experimental demonstration, two antennas are fabricated. The former dual-band antenna operating at f-1=3.5âGHz (Wimax) and f+1=5.25âGHz (WLAN) occupies an area of 0.21λ0Ă0.08λ0, and two dipolar radiation patterns are obtained with comparable gains of about 6.1 and 6.2âdB, respectively. The latter antenna advances in many aspects such as an ultrasmall size of only 0.16λ0Ă0.08λ0, versatile radiation patterns with a monopolar pattern at f0=2.4âGHz (Bluetooth), and a dipole one at f+1=3.5âGHz (Wimax) and also comparable antenna gains. Circuit parameters are extracted and researched. Excellent performances of the antennas based on hybrid resonators predict promising applications in multifunction wireless communication systems
Agri-food supply chain management : Bibliometric and content analyses
Agri-food supply chain management (ASCM) research has gained attraction in recent years. This study aims to examine the knowledge structure, trace the evolution of, and propose future research directions for ASCM by a systematic literature review combined with bibliometric and content analyses. A total of 1770 articles were selected from Scopus for bibliometric analyses. We conducted a content analysis based on 188 articles in six clusters selected from the co-citation analysis. This review provides insights into key authors, their affiliations, journal quality, and the prestige of the reviewed articles, aspects that have not been fully captured or evaluated by previous reviews. Using bibliometric tools, we identified six clusters for ASCM, based on which, future research directions are proposed. Content analysis provides additional insights in each cluster. In particular, sustainability runs through all the themes identified except for one
Geometric density of states of electronic structures for local responses: Phase information from the amplitudes of STM measurement
Electronic band structures underlie the physical properties of crystalline
materials, their geometrical exploration renovates the conventional cognition
and brings about novel applications. Inspired by geometry phases, we introduce
a geometric amplitude named as the geometric density of states (GDOS) dictated
by the differential curvature of the constant-energy contour. The GDOS
determines the amplitude of the real-space Green's function making it attain
the ultimate expression with transparent physics. The local responses of
crystalline materials are usually formulated by the real-space Green's
function, so the relevant physics should be refreshed by GDOS. As an example of
local responses, we suggest using scanning tunneling microscopy (STM) to
characterize the surface states of three-dimensional topological insulator
under an in-plane magnetic field. The GDOS favors the straightforward
simulation of STM measurement without resorting to Fourier transform of the
real-space measurement, and also excavates the unexplored potential of STM
measurement to extract the phase information of wavefunction through its
amplitude, i.e., the spin and curvature textures. Therefore, the proposed GDOS
deepens the understanding of electronic band structures and is indispensable in
local responses, and it should be universal for any periodic systems.Comment: 6 pages, 2 figure
A Comparison of Low Temperature Alkali and High Temperature Acid Pretreatments for Improving Saccharification of Spent Mushroom Substrate
AbstractLow temperature alkali (LTA) pretreatment and high temperature acid (HTA) pretreatment methods were applied to spent mushroom substrate (SMS) for providing comparative performance data on the enhancement of enzymatic saccharification and the change of composition and structure. LTA pretreatment contributed to higher lignin removal (67.6%) and enzymatic digestibility (85.6%) during enzymatic hydrolysis, while HTA pretreatment resulted in higher hemicellulose reduction (85.3%) but lower enzymatic digestibility (43.5%). The physical structure was destroyed at certain degree and changes in cellulose crystallinity occurred after both LTA and HTA pretreatments. Besides, the effect of lignin reduction in alkali pretreatment on glucose yield was studied. These results indicated that LTA pretreatment had the potential to be developed into a cost effective process for producing bioproducts from lignocellulosic materials
MicroRNA-1 acts as a tumor suppressor microRNA by inhibiting angiogenesis-related growth factors in human gastric cancer
Background
We recently reported that miR-1 was one of the most significantly downregulated microRNAs in gastric cancer (GC) patients from The Cancer Genome Atlas microRNA sequencing data. Here we aim to elucidate the role of miR-1 in gastric carcinogenesis.
Methods
We measured miR-1 expression in human GC cell lines and 90 paired primary GC samples, and analyzed the association of its status with clinicopathological features. The effect of miR-1 on GC cells was evaluated by proliferation and migration assay. To identify the target genes of miR-1, bioinformatic analysis and protein array analysis were performed. Moreover, the regulation mechanism of miR-1 with regard to these predicted targets was investigated by quantitative PCR (qPCR), Western blot, ELISA, and endothelial cell tube formation. The putative binding site of miR-1 on target genes was assessed by a reporter assay.
Results
Expression of miR-1 was obviously decreased in GC cell lines and primary tissues. Patients with low miR-1 expression had significantly shorter overall survival compared with those with high miR-1 expression (P = 0.0027). Overexpression of miR-1 in GC cells inhibited proliferation, migration, and tube formation of endothelial cells by suppressing expression of vascular endothelial growth factor A (VEGF-A) and endothelin 1 (EDN1). Conversely, inhibition of miR-1 with use of antago-miR-1 caused an increase in expression of VEGF-A and EDN1 in nonmalignant GC cells or low-malignancy GC cells.
Conclusions
MiR-1 acts as a tumor suppressor by inhibiting angiogenesis-related growth factors in human gastric cancer. Downregulated miR-1 not only promotes cellular proliferation and migration of GC cells, but may activates proangiogenesis signaling and stimulates the proliferation and migration of endothelial cells, indicating the possibility of new strategies for GC therapy
Endoscopic Ultrasonography in the Diagnosis and Treatment Strategy Choice of Esophageal Leiomyoma
OBJECTIVES: Esophageal leiomyoma is the most common benign tumor of the esophagus, and it originates from mesenchymal tissue. This study analyzed the clinicopathological characteristics of esophageal leiomyoma and aimed to evaluate the role of endoscopic ultrasonography in the diagnosis and treatment selection for these lesions. METHODS: Two hundred and twenty-five patients who had suspected esophageal leiomyomas in endoscopic ultrasonography were enrolled at the Endoscopy Center of The First Affiliated Hospital, Zhejiang University from January 1st, 2009 to May 31th, 2015. The main outcomes included the demographic and morphological characteristics, symptoms, comparisons of diagnosis and treatment methods, adverse events, and prognosis. RESULTS: One hundred and sixty-seven patients were diagnosed as having an esophageal leiomyoma by pathological examination. The mean patient age was 50.57±9.983 years. In total, 62.9% of the lesions originated from the muscularis mucosa, and the others originated from the muscularis propria. The median distance to the incisors was 30±12 cm. The median diameter was 0.72±0.99 cm. As determined by endoscopic ultrasonography, most existing leiomyomas were homogeneous, endophytic, and spherical. The leiomyomas from the muscularis mucosa were smaller than those from the muscularis propria and much closer to the incisors (
Up-Regulation of hsa-miR-210 Promotes Venous Metastasis and Predicts Poor Prognosis in Hepatocellular Carcinoma
Objective: To investigate the potential biomarkers for venous metastasis of hepatocellular carcinoma (HCC), and briefly discuss their target genes and the signaling pathways they are involved in.Materials and Method: The dataset GSE6857 was downloaded from GEO. Significantly differentially expressed miRNAs were identified using the R package âlimma,â After that, the survival analysis was conducted to discover the significance of these up-regulated miRNAs for the prognosis of HCC patients. Additionally, miRNAs which were up-regulated in venous metastasis positive HCC tissues and were significant for the prognosis of HCC patients were further verified in clinical samples using RT-qPCR. The miRNAs were then analyzed for their correlations with clinical characteristics including survival time, AFP level, pathological grade, TNM stage, tumor stage, lymph-node metastasis, distant metastasis, child-pugh score, vascular invasion, liver fibrosis and race using 375 HCC samples downloaded from the TCGA database. The target genes of these miRNAs were obtained using a miRNA target gene prediction database, and their functions were analyzed using the online tool DAVID.Results: 15 miRNAs were differentially expressed in samples with venous metastasis, among which 7 were up-regulated in venous metastasis positive HCC samples. As one of the up-regulated miRNAs, hsa-miR-210 was identified as an independent prognostic factor for HCC. Using RT-qPCR, it was evident that hsa-miR-210 expression was significantly higher in venous metastasis positive HCC samples (p = 0.0036). Further analysis indicated that hsa-miR-210 was positively associated with AFP level, pathological grade, TNM stage, tumor stage and vascular invasion. A total of 168 hsa-miR-210 target genes, which are mainly related to tumor metastasis and tumor signaling pathways, were also predicted in this study.Conclusion: hsa-miR-210 might promote vascular invasion of HCC cells and could be used as a prognostic biomarker
Complications after radical gastrectomy following FOLFOX7 neoadjuvant chemotherapy for gastric cancer
<p>Abstract</p> <p>Background</p> <p>This study assessed the postoperative morbidity and mortality occurring in the first 30 days after radical gastrectomy by comparing gastric cancer patients who did or did not receive the FOLFOX7 regimen of neoadjuvant chemotherapy.</p> <p>Methods</p> <p>We completed a retrospective analysis of 377 patients after their radical gastrectomies were performed in our department between 2005 and 2009. Two groups of patients were studied: the SURG group received surgical treatment immediately after diagnosis; the NACT underwent surgery after 2-6 cycles of neoadjuvant chemotherapy.</p> <p>Results</p> <p>There were 267 patients in the SURG group and 110 patients in the NACT group. The NACT group had more proximal tumours (P = 0.000), more total/proximal gastrectomies (P = 0.000) and longer operative time (P = 0.005) than the SURG group. Morbidity was 10.0% in the NACT patients and 17.2% in the SURG patients (P = 0.075). There were two cases of postoperative death, both in the SURG group (P = 1.000). No changes in complications or mortality rate were observed between the SURG and NACT groups.</p> <p>Conclusion</p> <p>The FOLFOX7 neoadjuvant chemotherapy is not associated with increased postoperative morbidity, indicating that the FOLFOX7 neoadjuvant chemotherapy is a safe choice for the treatment of local advanced gastric cancer.</p
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