Raman and photoreflectance study of Cu In,Ga S2 films and solar cells

The structural and optical properties of CuIn1 xGaxS2 CIGS , CdS CuIn1 xGaxS2, and ZnO CdS CuIn1 xGaxS2 polycrystalline films, with applications in photovoltaics, were studied by Raman and Photoreflectance PR spectroscopy for two different compositions, [Ga] [In] [Ga] 0.04 and 0.12, of the CuIn1 xGaxS2 absorber. The energy band gap of the absorber film was determined by fitting the PR spectra with a third derivative functional form. Moreover, the thickness of the film was calculated from the interference fringes observed in the PR spectra below band gap energy. Raman scattering was excited by the 514.5nm line of Ar laser and the 647.1nm line of Kr laser. The Raman spectra of the absorber films consist of phononmodes assigned to CuInS2, CuGaS2 and CuS. The results of the present study are discussed together with the results of SEM and XRD studies of the films and the results of electrical measurements performed on solar cells based on the CIGS absorber

Unravelling the therapeutic potential of IL-33 for atrophic AMD

Age-related macular degeneration (AMD), a degenerative disease affecting the retinal pigment epithelium (RPE) and photoreceptors in the macula, is the leading cause of central blindness in the elderly. AMD progresses to advanced stages of the disease, atrophic AMD (aAMD), or in 15% of cases “wet” or neovascular AMD (nAMD), associated with substantial vision loss. Whilst there has been advancement in therapies treating nAMD, to date, there are no licenced effective treatments for the 85% affected by aAMD, with disease managed by changes to diet, vitamin supplements, and regular monitoring. AMD has a complex pathogenesis, involving highly integrated and common age-related disease pathways, including dysregulated complement/inflammation, impaired autophagy, and oxidative stress. The intricacy of AMD pathogenesis makes therapeutic development challenging and identifying a target that combats the converging disease pathways is essential to provide a globally effective treatment. Interleukin-33 is a cytokine, classically known for the proinflammatory role it plays in allergic disease. Recent evidence across degenerative and inflammatory disease conditions reveals a diverse immune-modulatory role for IL-33, with promising therapeutic potential. Here, we will review IL-33 function in disease and discuss the future potential for this homeostatic cytokine in treating AMD

Laparoscopic Hernia Repair: a Two-Port Technique

Results of this study suggest that laparoscopic herniorrhaphy with a 2-port technique may allow a safe, efficient repair of ventral and incisional hernias

Comparison of Measured and Calculated Specific Resistances of Pd/Pt Interfaces

We compare specific resistances (AR equals area A times resistance R) of sputtered Pd/Pt interfaces measured in two different ways with no-free-parameter calculations. One way gives 2AR(Pd/Pt) of 0.29 (0.03) fohm-m(2) and the other 0.17 (0.13) fohm-m(2). From these we derive a best estimate of 2AR(Pd/Pt) of 0.28 (0.06) fohm-m(2), which overlaps with no-free-parameter calculations: 2AR(predicted) of 0.30 (0.04) fohm-m(2) for flat, perfect interfaces, or 0.33 (0.04) fohm-m(2) for interfaces composed of 2 monolayers of a 50percent-50percent PdPt alloy. These results support three prior examples of agreement between calculations and measurements for pairs of metals having the same crystal structure and the same lattice parameter to within 1 percent. We also estimate the spin-flipping probability at Pd/Pt interfaces as 0.13 (0.08).Comment: 3 pages, 3 figures, submitted for publication New version has corrected value of delta(Pd/Pt

A case of corticosteroid-dependent recurrent pericarditis with different response to two IL-1 blocking agents

Background: Recurrent pericarditis (RP) represents the most troublesome presentation of pericarditis and has a controversial pathogenesis that crosses infectious, auto-immune and auto-inflammatory pathways. It has been suggested that in some cases it might be an unrecognized auto-inflammatory disease. Recent studies have demonstrated that anakinra, an interleukin-1 receptor antagonist (IL-1RA), represents an effective treatment for the control of corticosteroid-dependent cases. Objectives: To describe a case of cortico-dependent recurrent pericarditis with a different response to two IL-1 blocking agents, anakinra and canakinumab. Methods: Case report Results: 11 years old boy who was admitted to our hospital because of acute precordial pain, orthopnea, fever and increased levels of acute phase reactants. Acute pericarditis was confirmed by echocardiography and a treatment with prednisone was started with prompt clinical improvement. Pericarditis recurred twice during steroid tapering (1mg/kg/day and 0.5mg/kg/day respectively). After exclusion of infectious origin, therapy with anakinra (2mg/kg/day) was established (to avoid long term steroid side effects) followed by dramatic clinical response and normalisation of laboratory findings despite tapering and discontinuation of prednisone. Treatment with anakinra was discontinued after 5 months with recurrence of pericarditis one week later. Anakinra was resumed with an excellent response. Five months later, while being in complete remission, anakinra was replaced with canakinumab (2mg/kg/dose) due to patient’s intolerance of daily injections. One week later, the patient experienced a new episode of pericarditis requiring corticotherapy. Two more relapses occured during steroid tapering, after 6 weeks and 2 months, in spite of the uptitration of canakinumab to 4mg/kg/dose. Anakinra was restarted with prompt clinical and biological remission and prednisone was discontinuated without recurrence of pericarditis. After further four weeks follow-up under anakinra alone, the pericarditis is still in remission. Conclusion: We describe a case of steroid-dependent RP with a dramatic therapeutic response to IL-1RA (anakinra) but without response to IL-1β monoclonal antibody (canakinumab). This unexpected observation could suggest that Il-1α might have a role in the pathogenesis of RP. The definitive potential usefulness of each IL-1 blocking agent requires confirmation in prospective controlled trials

Interleukin-33 regulates tissue remodelling and inhibits angiogenesis in the eye

Age-related macular degeneration (AMD) is the leading cause of central vision loss worldwide. Loss of retinal pigment epithelium (RPE) is a major pathological hallmark in AMD with or without pathological neovascularization. Although activation of the immune system is implicated in disease progression, pathological pathways remain diverse and unclear. Here, we report an unexpected protective role of a pro-inflammatory cytokine, interleukin-33 (IL-33) in ocular angiogenesis. IL-33 and its receptor (ST2) are expressed constitutively in human and murine retina and choroid. When RPE was activated, IL-33 expression was markedly elevated in vitro. We found that IL-33 regulated tissue remodelling by attenuating wound-healing responses, including reduction in migration of choroidal fibroblasts and retinal microvascular endothelial cells, and inhibition of collagen gel contraction. In vivo, local administration of recombinant IL-33 inhibited murine choroidal neovascularization (CNV) formation, a surrogate of human neovascular AMD, and this effect was ST2-dependent. Collectively, these data demonstrate IL-33 as a potential immunotherapy and distinguishes pathways for subverting AMD pathology

Exchange anisotropy, disorder and frustration in diluted, predominantly ferromagnetic, Heisenberg spin systems

Motivated by the recent suggestion of anisotropic effective exchange interactions between Mn spins in Ga$_{1-x}$Mn$_x$As (arising as a result of spin-orbit coupling), we study their effects in diluted Heisenberg spin systems. We perform Monte Carlo simulations on several phenomenological model spin Hamiltonians, and investigate the extent to which frustration induced by anisotropic exchanges can reduce the low temperature magnetization in these models and the interplay of this effect with disorder in the exchange. In a model with low coordination number and purely ferromagnetic (FM) exchanges, we find that the low temperature magnetization is gradually reduced as exchange anisotropy is turned on. However, as the connectivity of the model is increased, the effect of small-to-moderate anisotropy is suppressed, and the magnetization regains its maximum saturation value at low temperatures unless the distribution of exchanges is very wide. To obtain significant suppression of the low temperature magnetization in a model with high connectivity, as is found for long-range interactions, we find it necessary to have both ferromagnetic and antiferromagnetic (AFM) exchanges (e.g. as in the RKKY interaction). This implies that disorder in the sign of the exchange interaction is much more effective in suppressing magnetization at low temperatures than exchange anisotropy.Comment: 9 pages, 8 figure

Ferromagnetism in Diluted Magnetic Semiconductor Heterojunction Systems

Diluted magnetic semiconductors (DMSs), in which magnetic elements are substituted for a small fraction of host elements in a semiconductor lattice, can become ferromagnetic when doped. In this article we discuss the physics of DMS ferromagnetism in systems with semiconductor heterojunctions. We focus on the mechanism that cause magnetic and magnetoresistive properties to depend on doping profiles, defect distributions, gate voltage, and other system parameters that can in principle be engineered to yield desired results.Comment: 12 pages, 7 figures, review, special issue of Semicon. Sci. Technol. on semiconductor spintronic