Switchable filtering in vivaldi antenna

Presented is a new frequency switchable Vivaldi antenna that has a capability to operate in a wideband mode (1-3 GHz) and reconfigure to six different subbands of operations. The reconfiguration is realised by coupling and changing the effective electrical length of ring slots inserted in the structure by means of pin diode switches. To examine antenna performances, simulated and measured results are presented. Good impedance matches and radiation patterns have been achieved. The proposed antenna is suitable for wideband and multimode radio applications

Boundary interpolation for slice hyperholomorphic Schur functions

A boundary Nevanlinna-Pick interpolation problem is posed and solved in the quaternionic setting. Given nonnegative real numbers $\kappa_1, \ldots, \kappa_N$, quaternions $p_1, \ldots, p_N$ all of modulus $1$, so that the $2$-spheres determined by each point do not intersect and $p_u \neq 1$ for $u = 1,\ldots, N$, and quaternions $s_1, \ldots, s_N$, we wish to find a slice hyperholomorphic Schur function $s$ so that $$\lim_{\substack{r\rightarrow 1\\ r\in(0,1)}} s(r p_u) = s_u\quad {\rm for} \quad u=1,\ldots, N,$$ and $$\lim_{\substack{r\rightarrow 1\\ r\in(0,1)}}\frac{1-s(rp_u)\overline{s_u}}{1-r}\le\kappa_u,\quad {\rm for} \quad u=1,\ldots, N.$$ Our arguments relies on the theory of slice hyperholomorphic functions and reproducing kernel Hilbert spaces

Enantioselective Gas Chromatographic Analysis of Cyclopropane Derivatives

Chirasil-β-Dex was used as chiral stationary phase for the enantioselective gas chromatographic analysis of several new chiral cyclopropane derivatives. The GC method provides information about the chemical yields of the cyclopropane products, enantioselectivity, substrate specifity, and catalytic activity of the chiral catalysts used in the inter- and intra-molecular cyclopropanation reactions and avoids time-consuming work-up procedure

The impact of the Arab Spring on democracy and development in the MENA region

© 2019 John Wiley & Sons Ltd. In evaluating the consequences of the Arab Spring 8 years later, this paper not only focuses on the short-term consequences of the uprisings that swept through a number of countries in the Middle East and North African region but also analyzes the long-term prospects for democratization and development in the MENA region. The impact of the Arab Spring, despite its promises and the expectations of the rest of the world, has been dismal. While only Tunisia made a successful transition to a democratic polity with a constitution guaranteeing the basic rights of the people, the rest of the Arab Spring countries remain in the grip of the authoritarian rule, and countries such as Syria, Libya, and Yemen have been degenerated into bloody civil wars with dwindling hope of peace and freedom. On economic front, the growth has been tardy, showing little difference with countries that were unaffected by the Arab Spring. Yet, the paper concludes, echoing historian Eric Hobsbawm\u27s view, that revolutionary outcomes need not be judged as failure too quickly as they are likely to be partial success in the long term. The impact may be observed in the area of social opening, newer class alliances, and the emergence of a less rapacious, reformed, hybrid authoritarianism

Does ‘excessive’ anticoagulation predispose to periprosthetic infection?

Background Although persistent drainage and hematoma formation are recognized risk factors for the development of periprosthetic infection, it is not known if excess anticoagulation is a predisposing factor. Methods We conducted a 2 to 1 case-control study with 78 cases who underwent revision for septic failure. The controls underwent the same index procedure but did not develop consequent infection. Patient comorbidities, medications, intraoperative, and postoperative factors were compared. Results Postoperative wound complications including development of hematoma and wound drainage were significant risk factors for periprosthetic infection. A mean international normalized ratio of greater than 1.5 was found to be more prevalent in patients who developed postoperative wound complications and subsequent periprosthetic infection. Conclusions Cautious anticoagulation to prevent hematoma formation and/or wound drainage is critical to prevent periprosthetic infection and its undesirable consequences

Oral Transmission of Listeria Monocytogenes in Mice via Ingestion of Contaminated Food

L. monocytogenes are facultative intracellular bacterial pathogens that cause food borne infections in humans. Very little is known about the gastrointestinal phase of listeriosis due to the lack of a small animal model that closely mimics human disease. This paper describes a novel mouse model for oral transmission of L. monocytogenes. Using this model, mice fed L. monocytogenes-contaminated bread have a discrete phase of gastrointestinal infection, followed by varying degrees of systemic spread in susceptible (BALB/c/By/J) or resistant (C57BL/6) mouse strains. During the later stages of the infection, dissemination to the gall bladder and brain is observed. The food borne model of listeriosis is highly reproducible, does not require specialized skills, and can be used with a wide variety of bacterial isolates and laboratory mouse strains. As such, it is the ideal model to study both virulence strategies used by L. monocytogenes to promote intestinal colonization, as well as the host response to invasive food borne bacterial infection

Evidence supporting the use of peptides and peptidomimetics as potential SARS-CoV-2 (COVID-19) therapeutics

© 2020 Newlands Press. During a disease outbreak/pandemic situation such as COVID-19, researchers are in a prime position to identify and develop peptide-based therapies, which could be more rapidly and cost-effectively advanced into a clinical setting. One drawback of natural peptide drugs, however, is their proteolytic instability; peptidomimetics can help to overcome this caveat. In this review, we summarize peptide and peptide-based therapeutics that target one main entry pathway of SARS-CoV-2, which involves the host ACE2 receptor and viral spike (S) protein interaction. Furthermore, we discuss the advantages of peptidomimetics and other potential targets that have been studied using peptide-based therapeutics for COVID-19

Tracking the invasion of Hemiramphus far and Saurida undosquamis along the southern Mediterranean coasts: A Local Ecological Knowledge study

Local Ecological Knowledge of 92 professional fishers from Tunisia and Libya was used to investigate on the occurrence and establishment of the exotic Hemiramphus far and Saurida undosquamis along the southern Mediterranean coasts. According to fisherman’s knowledge, H. far and S. undosquamis appeared in Libya, in 1980 and 1989 respectively. In Tunisia these species were observed afterwards, in 2004 and 2007. Currently both H. far and S. undosquamis result to be well distributed and established, along the entire surveyed area, from Tubrouk (eastern Libya) to Tabarka (western Tunisia). A statistical analysis of the qualitative trends in abundance perceived by the respondents show that both species have significantly increased in abundance in Tunisia. In Libya an increase of the abundance of H. far was also apparent during the first decade of the 21st century but the current abundance of S. undosquamis resulted to be stable at the level of occasional captures. Given the lack of regular environmental monitoring programmes in the area, these findings provide information that could not have been obtained otherwise. Besides improving our understanding on the status and chronology of these invasions, this approach highlights the value of fisherman’s knowledge to reconstruct ecological process in the course of rapid historical modifications

Coal dust alters β-naphthoflavone-induced aryl hydrocarbon receptor nuclear translocation in alveolar type II cells

<p>Abstract</p> <p>Background</p> <p>Many polycyclic aromatic hydrocarbons (PAHs) can cause DNA adducts and initiate carcinogenesis. Mixed exposures to coal dust (CD) and PAHs are common in occupational settings. In the CD and PAH-exposed lung, CD increases apoptosis and causes alveolar type II (AT-II) cell hyperplasia but reduces CYP1A1 induction. Inflammation, but not apoptosis, appears etiologically associated with reduced CYP1A1 induction in this mixed exposure model. Many AT-II cells in the CD-exposed lungs have no detectable CYP1A1 induction after PAH exposure. Although AT-II cells are a small subfraction of lung cells, they are believed to be a potential progenitor cell for some lung cancers. Because CYP1A1 is induced via ligand-mediated nuclear translocation of the aryl hydrocarbon receptor (AhR), we investigated the effect of CD on PAH-induced nuclear translocation of AhR in AT-II cells isolated from <it>in vivo</it>-exposed rats. Rats received CD or vehicle (saline) by intratracheal (IT) instillation. Three days before sacrifice, half of the rats in each group started daily intraperitoneal injections of the PAH, β-naphthoflavone (BNF).</p> <p>Results</p> <p>Fourteen days after IT CD exposure and 1 day after the last intraperitoneal BNF injection, AhR immunofluorescence indicated that proportional AhR nuclear expression and the percentage of cells with nuclear AhR were significantly increased in rats receiving IT saline and BNF injections compared to vehicle controls. However, in CD-exposed rats, BNF did not significantly alter the nuclear localization or cytosolic expression of AhR compared to rats receiving CD and oil.</p> <p>Conclusion</p> <p>Our findings suggest that during particle and PAH mixed exposures, CD alters the BNF-induced nuclear translocation of AhR in AT-II cells. This provides an explanation for the modification of CYP1A1 induction in these cells. Thus, this study suggests that mechanisms for reduced PAH-induced CYP1A1 activity in the CD exposed lung include not only the effects of inflammation on the lung as a whole, but also reduced PAH-associated nuclear translocation of AhR in an expanded population of AT-II cells.</p

Tip-Leakage Vortex Inception on a Ducted Rotor

The tip-leakage vortex occurring on a ducted rotor was examined using both three component Laser Doppler Velocimetry (LDV) and planar Particle Imaging Velocimetry (PIV). The vortex strength and core size were examined for different vortex cross sections downstream of the blade trailing edge. The variability of these quantities are observed with PIV and the average quantities are compared between LDV and PIV. Developed cavitation is also examined for the leakage vortex. The implication of vortex variability on cavitation inception is discussed