Design of a Deployable Broadband Mesh Reflector Antenna for a SIGINT Satellite System Considering Surface Shape Deformation

In this paper, we propose a deployable broadband mesh reflector antenna for use in signals intelligence (SIGINT) satellite systems, considering performance degradation due to shape deformation. To maximize gain by increasing the diameter of the reflector while reducing the weight of the antenna, the reflector of the antenna is designed using lightweight silver-coated Teflon mesh. The mesh reflectors are typically expanded by tension to maintain their parabolic structure; thus, shape deformation cannot be avoided. This shape deformation results in shape differences between the surface of the mesh reflector and the ideal parabolic reflector, thus resulting in the degradation of the performance of the mesh reflector antenna. To observe this degradation, we analyze antenna performance according to the number of arms, the number of joints, the feed distance, and the distance from the reflector center to each joint. The performance of the mesh reflector antenna is examined using an effective lossy conducting surface (ELCS) that has the same reflectivity as the silver-coated Teflon mesh to reduce simulation time and computing resources. The designed silver-coated Teflon mesh reflector and the double-ridged feed antenna are fabricated, and the bore-sight gain is measured using the three-antenna method. The measured bore-sight gain of the proposed antenna is 31.6 dBi at 10 GHz, and the measured and simulated results show an average difference of 3.28 dB from 2 GHz to 18 GHz. The proposed deployable mesh reflector antenna can be used in a variety of applications where small stowed volume is required for mobility, such as mobile high-gain antennas as well as satellite antenna systems. Through this study, we demonstrate that shape deformation of the mesh reflector surface significantly affects the performance of reflector antennas.

Design of a mmWave Antenna Printed on a Thick Vehicle-Glass Substrate Using a Linearly Arrayed Patch Director and a Grid-Slotted Patch Reflector for High-Gain Characteristics

This paper proposes a 5G glass antenna that can be printed on the thick window glass of a vehicle. The proposed antenna consists of a coplanar waveguide (CPW), a printed monopole radiator, parasitic elements, a linearly arrayed patch director, and a grid-slotted patch reflector. The linearly arrayed patch director and grid-slotted patch reflector are applied to improve the bore-sight gain of the antenna. To verify the performance improvement and feasibility, the proposed antenna is fabricated, and a reflection coefficient and a radiation pattern are measured and compared with the simulation results. The measured reflection coefficient shows broadband characteristics of less than -10 dB from 24.1 GHz to 31.0 GHz (fractional bandwidth of 24.6%), which agrees well with the simulation results. The reflection coefficients are -33.1 dB by measurement and -25.7 dB by simulation, and the maximum gains are 6.2 dBi and 5.5 dBi at 28 GHz, respectively. These results demonstrate that the proposed antenna has high-gain characteristics being suitable for 5G wireless communications.

Phase transition behavior of silicone based liquid crystalline polymers

Phase transition behavior of silicone based liquid crystalline (LC) polymers with variable isotropic transition temperatures (Ti), synthesized from poly(methyl hydrosiloxane), 10-undecenoic acid based crosslinking agent and cholesterol based side chain mesogen, was studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and X-ray diffraction (XRD) measurements. The chemical structure of the mesogenic monomer and the LC polymers were confirmed by Fourier transform infra-red (FT-IR) spectroscopy and 1HNMR spectroscopy. DSC studies showed that the glass transition temperatures (Tg) and Ti of the LC polymers decreased with increasing proportion of mesogenic crosslinking agent at its low proportion and at its higher proportion Ti disappeared completely indicating that the polymeric chains had less chance to orient in the network structure. The results were consistent with the XRD and POM studies.

(1)H-NMR and NOE studies of 2-cephems and 3-cephems

The(1)H-NMR signals of 2-cephems and 3-cephems have been assigned and the Nuclear Overhauser Effect (NOE) study of these compounds was undertaken.

Clinical outcomes of adjuvant treatments for invasive thymoma: Dose chemotherapy influence prognosis?

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Background: The aim of this study was to evaluate therapeutic outcomes and to validate prognostic factors, including adjuvant chemotherapy, in resected thymoma patients who received adjuvant treatment. Methods: One hundred thymoma patients who received post-surgical adjuvant therapy from 1995 to 2005 were retrospectively reviewed. 55 patients received only radiotherapy for the adjuvant therapy, while 45 patients received both radiotherapy and chemotherapy. The total radiation dose was 45–63 Gy, with a median dose of 50.4 Gy. The chemotherapy consisted of 6 cycles of doxorubicin, cisplatin, vincristine, and cyclophosphamide. Treatments were applied every 3–4 weeks. The median follow-up duration was 65 months (range, 5–200 months). Results: The 5-year overall survival (OS) and disease- free survival (DFS) rates were 75.7% (89.2% in stage II, 67.9% in stage III, and 52.1% in stage IVA) and 70.3% (83% in stage II, 62.4% in stage III, and 33.6% in stage IVA) respectively. According to multivariate analysis, the prognostic factors for OS were age, WHO histology, Masaoka stage, and recurrence, while pleural involvement and WHO histology had statistically significant impacts on DFS. Higher radiation dosage, positive resection margins, and adjuvant chemotherapy did not influence survival outcomes. The most common relapse site was the pleura (15 patients, 53.6%). The toxicity from chemotherapy and radiotherapy was manageable, with no deaths due to toxicity. Conclusion: The prognosis of invasive thymoma was poor despite adjuvant treatments with radiotherapy and chemotherapy. In addition to WHO histology, pleural involvement was the most important prognostic factor for recurrence. The pleura was the most common relapse site. Therefore, new modalities to reduce pleural recurrence are warranted.

No significant financial relationships to disclose.

A phase II study of erlotinib treatment in advanced non-small cell lung cancer after failure of gefitinib: Is a clinical benefit still achievable?

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Background: To evaluate the efficacy and toxicity of erlotinib in patients (pts) with advanced NSCLC who had progression after treatment with gefitinib. Methods: The study included stage IIIB/IV recurrent or metastatic NSCLC pts who have received 2 or 3 prior chemotherapy regimens and showed documented disease progression during or within 4 months after treatment with gefitinib. Pts received erlotinib 150 mg daily until disease progression or unacceptable toxicity. We analyzed EGFR mutations and other genetic abnormality from available tumor samples. Results: Pts and disease characteristics (n = 21) included median age 56 years; number of prior chemotherapy regimens (two, n=10; three, n=11); male (n=10); adenocarcinoma (n=15); and smoking status (never, n=11; former, n=3; current, n=7). Among the 17 pts with tumor samples available, EGFR mutation were detected in 5 (29.4 %). The DCR and RR for all pts were 28.6% (95% CI, 16.7 to 59.6%) and 9.5% (95% CI, 5.6 to 19.8%). All responders were EGFR nonmutants, with long duration of disease control on prior gefitinib therapy (>180 days). The median duration of disease control was 125 days (95% CI, 73–261 days). The median progression-free survival and overall survival were 60 days (95% CI, 43–77 days) and 158 days (95% CI, 141–175 days), respectively. Pts who had SD on gefitinib showed significantly higher DCR (75% vs. 17.6% in non-SD pts, P= 0.050) and RR (50.0% vs. 0% in non-SD pts, P= 0.029). These pts also showed longer median PFS (140 vs. 37 days in non-SD pts, P= 0.005) and OS (not reached vs. 120 days in non-SD pts, P= 0.043). Among 17 pts with biomarker results available, EGFR nonmutants who had SD on gefitinib showed significantly higher DCR (100% vs. 21.4% in non-SD and/or EGFR mutants, P= 0.029) and RR (RR, 66.7 % vs. 0 % in non-SD and/or EGFR mutants, P= 0.022). Conclusions: Erlotinib seems to be a potential therapeutic option for the treatment of selected pts with gefitinib-nonresponsive, EGFR nonmutant, advanced NSCLC.

No significant financial relationships to disclose.

[Table: see text]

Synthesis of 6-exomethylenepenams as beta-lactamase inhibitors

The 6,6-dibromopenam (6) was treated with CH3MgBr and carbaldehyde 5 to afford the hydroxy compound 7, which was reacted with acetic anhydride to give acetoxy compound 8. The deacetobromination of 8 with zinc and acetic acid gave 6-exomethylenepenams, E-isomer 10 and Z-isomer 9, which was oxidized to sulfone 11 by m-CPBA. The p-methoxybenzyl compounds were deprotected by AlCl3 and neutralized to give the sodium salts 12, 13 and 14.

Detection of a dup(17q) and inv(16) by fluorescence in situ hybridization in acute myelomonocytic leukemia

Two cases of acute myelomonocytic leukemia (AMMoL) of FAB type M4Eo are described in which a primary subclone containing a dup(17)(q21q25) and a subclone containing dup(17)(q21q25), inv(16)(p13q22) were seen in one patient, and -7, dup(17)(q21q25) in another. Fluorescence in situ hybridization (FISH) was carried out for the confirmation of the duplicated segment and breakpoint of inv(16). Inv(16) is a well known anomaly in AMMoL, whereas dup(17q) is rare though as not yet confirmed, this anomaly could be a nonrandom or novel change in AMMoL.

Synthesis and beta-lactamase inhibitory activity of 6-[(1-heteroarylthioethyl-1,2,3-triazol-4-yl)-methylene]penam sulfones

The synthesis of beta-lactamase inhibitory activity of a series of sodium 6-[(1-heteroarylthioethyl-1,2,3-triazol-4-yl)methylene]pe nicillanate, 1,1-dioxides are described. Their activity was compared with tazobactam and sulbactam. The Z-isomers were more active than the E-isomers. The in vitro activity of the Z-isomers of the phenylthiadiazole derivatives (13a and 15a) was better than sulbactam against the tested beta-lactamases and comparable to tazobactam especially against TEM-2 and cephalosporinase. But their synergistic activity with five antibiotics was inferior to tazobactam.

Synthesis and cytotoxic activity of (E)-1-(2-nitrovinyl) and 1-[N-(tert-butylformiminyl)]-substituted 1,4-dihydropyridines and 2-pyridones

1-(2-Nitrovinyl) derivatives of nuclear substituted 1,4-dihydropyridines (7a-c), and 1-(N-tert-butyl-formiminyl) derivatives of 1,4-dihydropyridines (9a-c) or 2-pyridones (11a-c) were synthesized for evaluation as cytotoxic agents (see Table I for structures). The in vitro cytotoxic activities, determined in the L1210 assay, indicated that the 4-substituent on a 1,4-dihydropyridine ring system was a determinant of activity in both the 1-(2-nitrovinyl) (7) and 1-(N-tert-butylformiminyl) (9) series, the relative activity order being n-Bu > Ph > Me. In the 1-(N-tert-butylformiminyl) series, the 1,4-dihydropyridine derivatives (9) were generally more cytotoxic than the 2-pyridone derivatives (11). The most active compound was 1-(N-tert-butylformiminyl)-3-(4,4-dimethyloxazolin-2-yl)-4-n -butyl-1,4- dihydropyridine (9b), but it was 2-3 log units less active than the reference standard melphalan.