Collective Antenna Effects in the Terahertz and Infrared Response of Highly Aligned Carbon Nanotube Arrays

We study macroscopically-aligned single-wall carbon nanotube arrays with uniform lengths via polarization-dependent terahertz and infrared transmission spectroscopy. Polarization anisotropy is extreme at frequencies less than $\sim$3 THz with no sign of attenuation when the polarization is perpendicular to the alignment direction. The attenuation for both parallel and perpendicular polarizations increases with increasing frequency, exhibiting a pronounced and broad peak around 10 THz in the parallel case. We model the electromagnetic response of the sample by taking into account both radiative scattering and absorption losses. We show that our sample acts as an effective antenna due to the high degree of alignment, exhibiting much larger radiative scattering than absorption in the mid/far-infrared range. Our calculated attenuation spectrum clearly shows a non-Drude peak at $\sim$10 THz in agreement with the experiment.Comment: 5 pages, 5 figure

Theory of Bi2_2Sr2_2CaCu2_2O8+δ_{8+\delta} Cross-Whisker Josephson Junctions

Takano {\it et al.} [Phys. Rev. B {\bf 65}, 140513 (2002) and unpublished] made Josephson junctions from single crystal whiskers of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ crossed an angle $\phi_0$ about the $c$ axis. From the mesa structures that formed at the cross-whisker interface, they inferred a critical current density $J_c(\phi_0)$. Like the single crystal results of Li {\it et al.} [Phys. Rev. Lett. {\bf 83}, 4160 (1999)], we show that the whisker data are unlikely to result from a predominantly d-wave order parameter. However, unlike the single crystals, these results, if correct, require the whisker c-axis transport to be coherent.Comment: 5 pages, 4 figures, accepted for publication in Physical Review

Gaussian Tunneling Model of c-Axis Twist Josephson Junctions

We calculate the critical current density $J^J_c$ for c-axis Josephson tunneling between identical high temperature superconductors twisted an angle $\phi_0$ about the c-axis. We model the tunneling matrix element squared as a Gaussian in the change of wavevector q parallel to the junction, $<|t({\bf q})|^2>\propto\exp(-{\bf q}^2a^2/2\pi^2\sigma^2)$. The $J^J_c(\phi_0)/J^J_c(0)$ obtained for the s- and extended-s-wave order parameters (OP's) are consistent with the Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ data of Li {\it et al.}, but only for strongly incoherent tunneling, $\sigma^2\ge0.25$. A $d_{x^2-y^2}$-wave OP is always inconsistent with the data. In addition, we show that the apparent conventional sum rule violation observed by Basov et al. might be understandable in terms of incoherent c-axis tunneling, provided that the OP is not $d_{x^2-y^2}$-wave.Comment: 6 pages, 6 figure

Overexpression of Chitinase 3-Like 1/YKL-40 in Lung-Specific IL-18-Transgenic Mice, Smokers and COPD

We analyzed the lung mRNA expression profiles of a murine model of COPD developed using a lung-specific IL-18-transgenic mouse. In this transgenic mouse, the expression of 608 genes was found to vary more than 2-fold in comparison with control WT mice, and was clustered into 4 groups. The expression of 140 genes was constitutively increased at all ages, 215 genes increased gradually with aging, 171 genes decreased gradually with aging, and 82 genes decreased temporarily at 9 weeks of age. Interestingly, the levels of mRNA for the chitinase-related genes chitinase 3-like 1 (Chi3l1), Chi3l3, and acidic mammalian chitinase (AMCase) were significantly higher in the lungs of transgenic mice than in control mice. The level of Chi3l1 protein increased significantly with aging in the lungs and sera of IL-18 transgenic, but not WT mice. Previous studies have suggested Chi3l3 and AMCase are IL-13-driven chitinase-like proteins. However, IL-13 gene deletion did not reduce the level of Chi3l1 protein in the lungs of IL-18 transgenic mice. Based on our murine model gene expression data, we analyzed the protein level of YKL-40, the human homolog of Chi3l1, in sera of smokers and COPD patients. Sixteen COPD patients had undergone high resolution computed tomography (HRCT) examination. Emphysema was assessed by using a density mask with a cutoff of −950 Hounsfield units to calculate the low-attenuation area percentage (LAA%). We observed significantly higher serum levels in samples from 28 smokers and 45 COPD patients compared to 30 non-smokers. In COPD patients, there was a significant negative correlation between serum level of YKL-40 and %FEV1. Moreover, there was a significant positive correlation between the serum levels of YKL-40 and LAA% in COPD patients. Thus our results suggest that chitinase-related genes may play an important role in establishing pulmonary inflammation and emphysematous changes in smokers and COPD patients

Effects of Different Up-Dosing Regimens for Hymenoptera Venom Immunotherapy on Serum CTLA-4 and IL-10

BACKGROUND: Cytotoxic T lymphocyte associated antigen-4 (CTLA-4) is involved in the activation pathways of T lymphocytes. It has been shown that the circulating form of CTLA-4 is elevated in patients with hymenoptera allergy and can be down regulated by immunotherapy. OBJECTIVE: to assess the effects on CTLA-4 of venom immunotherapy, given with different induction protocols: conventional (6 weeks), rush (3 days) or ultra rush (1 day). METHODS: Sera from patients with hymenoptera allergy were collected at baseline and at the end of the induction phase. CTLA-4 and IL-10 were assayed in the same samples. A subset of patients were assayed also after 12 months of VIT maintenance. RESULTS: Ninety-four patients were studied. Of them, 50 underwent the conventional induction, 20 the rush and 24 the ultra-rush. Soluble CTLA-4 was detectable in all patients at baseline, and significantly decreased at the end of the induction, irrespective of its duration. Of note, a significant decrease of sCTLA-4 could be seen already at 24 hours. In parallel, IL-10 significantly increased at the end of the induction. At 12 months, sCTLA-4 remained low, whereas IL-10 returned to the baseline values. CONCLUSIONS: Serum CTLA4 is an early marker of the immunological effects of venom immunotherapy, and its changes persist after one year of maintenance treatment

Responsiveness of blood and sputum inflammatory cells in Japanese COPD patients, non-COPD smoking controls, and non-COPD nonsmoking controls

Tomotaka Kawayama,1 Takashi Kinoshita,1 Kazuko Matsunaga,2 Akihiro Kobayashi,3 Tomoyuki Hayamizu,4 Malcolm Johnson,5 Tomoaki Hoshino11Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, 2Department of Respiratory Medicine, Fukuoka Sanno Hospital, Fukuoka, 3Biomedical Data Science Department, 4Medical Affairs Respiratory Department, GlaxoSmithKline, Shibuya-ku, Tokyo, Japan; 5Respiratory Global Franchise, GlaxoSmithKline, Uxbridge, UKPurpose: To compare pulmonary and systemic inflammatory mediator release, pre- and poststimulation, ex vivo, in cells from Japanese patients with chronic obstructive pulmonary disease (COPD), non-COPD smoking controls, and non-COPD nonsmoking controls (NSC).Patients and methods: This was a nontreatment study with ten subjects per group. Inflammatory biomarker release, including interleukin (IL)-6 and -8, matrix metalloproteinase-9, and tumor necrosis factor (TNF)-&alpha;, was measured in peripheral blood mononuclear cells (PBMC) and sputum cells with and without lipopolysaccharide or TNF-&alpha; stimulation.Results: In PBMC, basal TNF-&alpha; release (mean &plusmn; standard deviation) was significantly different between COPD (81.6&plusmn;111.4 pg/mL) and nonsmoking controls (9.5&plusmn;5.2 pg/mL) (P&lt;0.05). No other significant differences were observed. Poststimulation biomarker release tended to increase, with the greatest changes in the COPD group. The greatest mean increases were seen in the lipopolysaccharide-induced release of matrix metalloproteinase-9, TNF-&alpha;, and IL-6 from PBMC. Pre- and poststimulation data from sputum samples were more variable and less conclusive than from PBMC. In the COPD group, induced sputum neutrophil levels were higher and macrophage levels were lower than in either control group. Significant correlations were seen between the number of sputum cells (macrophages and neutrophils) and biomarker levels (IL-8, IL-6, and TNF-&alpha;).Conclusion: This was the first study to compare cellular inflammatory mediator release before and after stimulation among Japanese COPD, smoking controls, and nonsmoking controls populations. Poststimulation levels tended to be higher in patients with COPD. The results suggest that PBMC are already preactivated in the circulation in COPD patients. This provides further evidence that COPD is a multicomponent disease, involving both airway and systemic inflammation.Keywords: chronic obstructive pulmonary disease, lipopolysaccharide, peripheral blood mononuclear cells, sputum, tumor necrosis factor-&alpha

&ldquo;Frequent exacerbator&rdquo; is a phenotype of poor prognosis in Japanese patients with chronic obstructive pulmonary disease

Ryusuke Tomioka,1,2 Tomotaka Kawayama,1 Masashi Suetomo,1,2 Takashi Kinoshita,1 Yoshihisa Tokunaga,1 Haruki Imaoka,1 Kazuko Matsunaga,1 Masaki Okamoto,1 Tomoaki Hoshino1 1Division of Respirology, Neurology, and Rheumatology, Department of Medicine, Kurume University School of Medicine, Kurume, 2Respiratory Medicine, Chikugo City Hospital, Chikugo, JapanBackground: The prognosis of Japanese patients with COPD who suffer repeated exacerbations is unclear, although Westerners with such episodes have a poor prognosis.Materials and methods: We conducted a 1-year prospective observational trial involving 90 Japanese patients with COPD: 58 nonexacerbators, 12 infrequent exacerbators, and 20 frequent exacerbators classified on the basis of exacerbation frequency (zero, one, and two or more exacerbations/year), respectively, during the previous year were observed prospectively for 1 year. The characteristics of frequent exacerbators, the frequency of exacerbation, and the period until the first event were then compared among the groups.Results: A total of 78 patients completed the study. Frequent exacerbators had a significantly higher risk of frequent exacerbation in the following year than the case for nonexacerbators (odds ratio [95% confidence interval] 2.94 [1.21&ndash;7.17], P=0.0340), but not in comparison with infrequent exacerbators (1.51 [0.49&ndash;4.63], P&gt;0.05). The mean annual frequency of exacerbations in the following year was significantly (P=0.0020) higher in the frequent exacerbators (1.4 exacerbations/year) than in the nonexacerbators (0.4), but not in the infrequent exacerbators (0.9, P&gt;0.05). The mean period until the first exacerbation was significantly shorter in the frequent exacerbators than in the infrequent or nonexacerbators (P=0.0012). Independent risk factors for future frequent exacerbation included the presence of gastroesophageal reflux disease, more severe airflow obstruction, and use of inhaled corticosteroids.Conclusion: Our present results indicate that Japanese COPD patients suffering frequent exacerbation have a poor prognosis. The characteristics of Japanese and Western COPD patients suffering frequent exacerbation are similar.Keywords: COPD, hospitalization, exacerbation, Japanes

Terahertz emission from coherent phonons in lithium ternary chalcopyrite crystals illuminated by 1560 nm femtosecond laser pulses

We have investigated terahertz (THz) emission from lithium ternary chalcopyrite crystals LiInSe2, LiGaSe2, LiInS2, and LiGaS2 that were illuminated by 1560 nm femtosecond pump laser pulses. Monocyclic THz emission caused by nonlinear optical effects was initially observed in all the illuminated crystals. Narrow-band THz emission from the coherent phonons were observed in LiInSe2 (2.87 THz) and LiGaSe2 (2.60 and 3.45 THz). These phonon modes were most likely caused by impulsive stimulated Raman scattering

Implications of phase-segregation on structure, terahertz emission and magnetization of Bi (Fe

Structural, magnetic and terahertz emission properties of Bi (Fe$_{1-x}$Mnx)O3  (0 $\leqslant$ x $\leqslant$ 0.5) thin films of various thicknesses were studied. A transition from coherently strained structure to relaxed structure at a film thickness (t) of ~ 80– 90 nm occurs only for x < 0.2. It is shown that terahertz-emission efficiency is not deteriorated with increasing Mn-doping (x). The magnetic moment of thin films (t $\leqslant$ 85 nm) exhibits only a weak enhancement with increasing x —a feature suggesting that Mn-doping is ineffective in inducing ferromagnetism in BiFeO3. The thicker films (t $\geqslant$ 150 nm), on the contrary, possess larger magnetic moment which evidently arises from the segregated magnetic MnFe2O4 phase