Design of compact polarization rotator using simple silicon nanowires

In this paper, an ultracompact design of a polarization rotator (PR) based on a silicon-on-insulator (SOI) platform is presented. The design contains two simple silicon nanowires but with unequal width, which will be easier to fabricate. It is shown here that a low-loss, wide-bandwidth, and 52.8-μm-long compact PR with polarization cross talk of −20  dB can be achieved. A full-vectorial finite element method and the least-squares boundary residual method are used to study the effects of the fabrication tolerances. This design shows reasonably stable performances

Design of a Compact Polarization Splitter by Using Identical Coupled Silicon Nanowires

Design of an ultra-compact polarization splitter (PS) based on silicon-on-insulator platform is presented. The design incorporates two simply coupled identical silicon nanowires, which can be easily fabricated by using standard Complementary Metal-Oxide-Semiconductor technology and fully compatible with standard active silicon photonics platforms. It is shown here that a low-loss, 17.90 μm long compact PS, and wide bandwidth over the entire C-band can be achieved. Important waveguide design parameters such as the guide width, height, and separation between them have been optimized, and modal birefringence and wavelength dependence have been calculated by using a full-vectorial H-Field finite element method. The optical power transfer characteristics have been calculated by using a rigorous least squares boundary residual method

Jet thermalization in QCD kinetic theory

We perform numerical studies in QCD kinetic theory to investigate the energy and angular profiles of a high energy parton - as a proxy for a jet produced heavy ion collisions - passing through a Quark-Gluon Plasma (QGP). We find that the fast parton loses energy to the plasma mainly via a radiative turbulent gluon cascade that transport energy locally from the jet down to the temperature scale where dissipation takes place. In this first stage, the angular structure of the turbulent cascade is found to be relatively collimated. However, when the lost energy reaches the plasma temperature is it rapidly transported to large angles w.r.t. the jet axis and thermalizes. We investigate the contribution of the soft jet constituents to the total jet energy. We show that for jet opening angles of about 0.3 rad or smaller the effect is negligible. Conversely, larger opening angles become more and more sensitive to the thermal component of the jet and thus to medium response. Our result showcase the importance of the jet cone size in mitigating or enhancing the details of dissipation in jet quenching observables.Comment: 41 pages, 11 figures

Study the effect of echinacea purpurea extract on cellular delayed type hypersensitivity and splenocyte proliferation in BALB/c mice

Objective: Purple cone flower plant (Echinacea purpurea) is one of the most important Herbal products in many countries. Up to now a lot of experiments demonstrated the controversial effects of this herb on immune system . In this research we study the in vivo and in vitro effect of Iranian E.purpurea extract on cellular immunity. Materials and Methods: At first we determined the lethal dose of E.purpurea extract after intraperitoneal injection in BALB/c mice. Then we made five groups of mice and treat them by four times intraperitoneal injection of 1 ml extract at different doses (0, 0.4, 2, 10 and 50 mg/ml) during two weeks. Splenocyte proliferation response to extract was assessed by MTT method. Delayed-Type Hypersensitivity (DTH) response was evaluated by priming mice with 1×108 Sheep Red Blood Cell (SRBC) injected subcutaneously in the back on day 7after treatment. Results: As a result no significant variation in weight and spleen index of test groups to control was observed. Splenocyte proliferation and DTH response of test groups to control increased significantly (p<0.05). Conclusion: However these data confirmed the results of previous studies, in addition presented the first results about significant increase in DTH response that could not be seen before. Scince the main reason of this difference refers to active compounds of herb extract, comparing effective component of this extract with that of E.purpurea cultivated in other geographical condition will consider as the next studies

Echinacea purpurea polysaccharide reduces the latency rate in herpes simplex virus type-1 infections

Objective: During the latency period of herpes simplex virus type-1 (HSV-1), the virus can occasionally reactivate, travel back to the eye and cause recurrent ocular disease. As this condition arises from the ability of HSV-1 to produce a dormant infection, effective medication to prevent the virus enter a latent state should prevent it. In this study, we applied Echinacea polysaccharide (EP) fraction as prophylactic mediator for latency prevention. Methods: In order to investigate the protective properties of EP, we evaluated its immunostimulatory functions on different immune aspects that play important roles in latency prevention (particularly IFN-γ as one of the main indicators of cellular immunity and latency). Finally, we assessed establishment of latency by detection of thymidine kinase gene in trigeminal ganglia of BALB/c mice. Results: We demonstrated that EP promotes immune response, leading to a reduced latency rate, and it has a promising effect on latency prevention. Conclusion: EP was able to exert an antiviral action on the development of recurrent HSV-1 disease when supplied prior to infection. © 2009 S. Karger AG, Basel

Cryoprotectant contents of overwintering adults of elm leaf beetle, Xanthogaleruca luteola (Col.: Chrysomelidae)

The elm leaf beetle, Xanthogaleruca luteola (Muller), is one of the most destructive pests of elm trees that overwinters as diapausing adult. The main cryoprotectants and their seasonal fluctuations in the elm leaf beetles were analyzed based on the monthly level of polyhydric alcohol from October 2008 through June 2009, using high performance liquid chromatography (HPLC). The compounds myo-inositol, trehalose, glucose and glycerol were found to be the most important polyols in the overwintering adults, of which myo-inositol content exhibited an inversely significant correlation with temperature fluctuations (r = -0.814, P = 0.014). The highest level of myo-inositol was observed in December (32.6 ± 2.7 µmol g-1 fresh body weight), while its lowest level was recorded in April (3.0 ± 0.4 µmol g-1 fresh body weight). The total concentration of all cryoprotectants was 100.7 ± 7.6 µmol g-1 fresh body weights in January. The results underline the influential role of myo-inositol, trehalose and glucose compounds in enhancing the cold tolerance of elm leaf beetles and their chance of survival during freezing winter days

Hypothesis for the management and treatment of the COVID-19-induced acute respiratory distress syndrome and lung injury using mesenchymal stem cell-derived exosomes

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of the coronaviridae that causes respiratory disorders. After infection, large amounts of inflammatory cytokines are secreted, known as the cytokine storm. These cytokines can cause pulmonary damage induced by inflammation resulting in acute respiratory distress syndrome (ARDS), and even death. One of the therapeutic approaches for treatment of ARDS is a mesenchymal stem cell (MSC). MSCs suppress inflammation and reduce lung injury through their immunomodulatory properties. MSCs also have the potential to prevent apoptosis of the lung cells and regenerate them. But our suggestion is using MSCs-derived exosomes. Because these exosomes apply the same immunomodulatory and tissue repair effects of MSCs and they don't have problems associated to cell maintenance and injections. For investigation the hypothesis, MSCs should be isolated from tissues and characterized. Then, the exosomes should be isolated from the supernatants and characterized. These exosomes should be injected into a transgenic animal for COVID-19. In the final section, lung function assessment, histological examination, micro-CT, differential leukocyte, viral load analysis, cytokine assay, and CRP level analysis can be investigated. COVID-19 treatment is currently focused on supportive therapies and no vaccine has been developed for it. So, numerous researches are needed to find potential therapies. Since the pathogenesis of this disease was identified in previous studies and can cause lung injury with ARDS, investigation of the therapeutic approaches that can suppress inflammation, cytokine storm and ARDS can be helpful in finding a novel therapeutic approach for this disease. © 202

The 4 per 1000 initiative.

Soil organic matter is at the nexus of global challenges: food security, climate change adaptation and mitigation, soil security. The 4 per 1000 initiative, launched at the Climate COP21 within the Lima-Paris Action Agenda proposes to increase soil organic carbon (SOC) stocks to simultaneously address all these challenges. It directly addresses three sustainable development goals: SDG2 ?no hunger?, SDG13 ?Climate action?, and SDG15 ?Life on land? and indirectly concerns several others. The initiative targets agricultural soils in priority, which are often the most degraded soils and because of the high expected benefits in terms of soil fertility and hence of productivity. A range of agricultural practices are available that allow to increase SOC stocks while ensuring a resilient, productive and environmentally friendly agriculture, so that a large-scale deployment can be aimed at. Here, we review and discuss the main limits and criticisms addressed to the 4 per 1000 initiative