Efficiency Drop in Green InGaN/GaN Light Emitting Diodes: The Role of Random Alloy Fluctuations.

White light emitting diodes (LEDs) based on III-nitride InGaN/GaN quantum wells currently offer the highest overall efficiency for solid state lighting applications. Although current phosphor-converted white LEDs have high electricity-to-light conversion efficiencies, it has been recently pointed out that the full potential of solid state lighting could be exploited only by color mixing approaches without employing phosphor-based wavelength conversion. Such an approach requires direct emitting LEDs of different colors, including, in particular, the green-yellow range of the visible spectrum. This range, however, suffers from a systematic drop in efficiency, known as the "green gap," whose physical origin has not been understood completely so far. In this work, we show by atomistic simulations that a consistent part of the green gap in c-plane InGaN/GaN-based light emitting diodes may be attributed to a decrease in the radiative recombination coefficient with increasing indium content due to random fluctuations of the indium concentration naturally present in any InGaN alloy.

Topical corticosteroids with topical cyclosporine A versus topical corticosteroids alone for immunological corneal graft rejection.

PURPOSE: To assess the efficacy and safety of supplementing topical cyclosporine A (CsA) to topical corticosteroids (CS), in the prophylaxis and treatment of corneal graft rejection following penetrating keratoplasty (PK). METHODS: Meta-analysis. Search was performed in PubMed, CENTRAL, ClinicalTrials.gov, reference lists of articles and conference proceedings. Primary outcomes: 1-year rejection-free survival rate (prophylaxis); resolution rate of rejection episodes (treatment). Secondary outcomes: 6- and 24-month rejection-free graft survival rate, number of rejection episodes during follow-up, time-to-resolution of rejection episode, 12- and 24-months graft survival rate, adverse events. Subgroup analyses were planned for high-risk grafts; primary vs. secondary prophylaxis of graft rejection episodes; and CsA concentrations of 0.05%, 1%, and 2%. RESULTS: Five studies of moderate methodological quality were included (one retrospective, four RCT), assessing 459 eyes (CS + CsA 226, CS 233). In the prophylaxis setting, supplemental CsA was associated with a higher rejection-free survival rate at 12-months (RR 1.25, 95% CI: 1.00-1.56, p = 0.05) and 24-months post-PK (RR 1.56, 95% CI: 1.15-2.11, p < 0.01), though no differences were found at the 6-months timepoint (p = 0.93). This effect was mostly verified using CsA 2% in the high-risk subset of patients. In the treatment setting, no differences were found in the resolution rate of rejection episodes (p = 0.23). No differences existed on drug-related adverse events. CONCLUSION: In the prophylaxis of rejection episodes post-PK, the combined regimen of CS + CsA was associated with a higher 1- and 2-year rejection-free graft survival rate. Subgroup analysis mostly supported the use of CsA 2% for high-risk grafts. Further studies are needed to validate these results.

A Non-Infectious Uveitis Multidisciplinary Clinic in a Tertiary Referral Center: Clinical Impact and Added Value.

Non-infectious uveitis (NIU) is a group of sight-threatening diseases that generates significant burden for the healthcare systems due to its adverse outcomes, irreversible structural complications in the eye with loss of visual function, limited clinical expertise and low-grade evidence for best practice. The usefulness of multidisciplinary care, specifically close collaboration between Rheumatologists and Ophthalmologists in NIU, has been emphasized in the literature. In this paper, the assessment tools and protocols used in our clinic are depicted and an overview of our activity with a brief description of the patients included in our registry, between 2018 and 2020 is provided. The cohort of 290 patients assessed in our NIU clinic, their demographics, sources of referral, details about immunosuppression treatment, and internal and external collaborations is described. This experience-based manuscript aims to describe the general functioning of our multidisciplinary NIU clinic, highlighting the benefits and drawbacks of multidisciplinary team management in patients with NIU, ultimately initiating a dialogue on what an NIU clinic should be and providing information for newly NIU clinics start-up. In conclusion, establishing a standardized and multidisciplinary clinic in NIU allows to systematically observe and follow-up this infrequent disease at a tertiary hospital level, thus improving quality of care delivery and research avenues.

Characterization of posterior corneal astigmatism in a population with keratoconus.

Background: The curvature of the anterior corneal surface is traditionally used as a surrogate to estimate corneal astigmatism. In recent years, increasing importance has been attributed to posterior corneal astigmatism as an indicator. Our aim is to characterize the posterior corneal surface in a population with keratoconus and investigate its predictive value to keratoconus progression. Methods: Retrospective study from a tertiary care centre (Hospital de Santa Maria, Lisbon, Portugal). Eighty-five patients (85 eyes) with keratoconus were included. All patients had two tomographical examinations ≥12 months apart (Pentacam HR). Vector analysis was used to calculate anterior (ACA), posterior (PCA), and total corneal astigmatism (TCA). Multivariate logistic regression was used to assess the predictive value of PCA to keratoconus progression, adjusting for ACA, TCA and several tomographical indices. Results: Study participants had a mean age of 32 (SD = 12.5) years. Mean tomographical keratoconus classification was 2.16 (SD = 0.95), with a mean Kmax of 55.8D (SD = 7.8). Mean power of PCA, ACA and TCA was, respectively, -0.88D (SD = 0.84), 3.74D (SD = 2.36), and 3.06D (SD = 2.01) and its centroids were 0.44D x 15º, 1.65D x 112º, and 1.61D x 106º, respectively. The power of PCA was ≥0.50, 1.00 and 2.00D in 75.3%, 32.9%, and 3.5% of patients, respectively, inducing against-the-rule astigmatism in 60.0% of patients. On average, ACA overestimated TCA in 0.35D x 151º (p < .01). ACA and TCA were highly correlated but showed a lack of agreement for clinical purposes. A predictive role for PCA was excluded. Conclusions: In this population with keratoconus, PCA contributed substantially to TCA. However, PCA was not a valuable predictor for disease progression.

DMEK versus DSAEK for Fuchs' endothelial dystrophy: A meta-analysis.

PURPOSE:: To compare the safety and efficacy profiles of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in adult patients with Fuchs' endothelial dystrophy. METHODS:: Electronic database search on MEDLINE and CENTRAL from inception to August 2017. We included all comparative studies of DMEK versus DSAEK in patients with diagnosed Fuchs' endothelial dystrophy. Studies assessing rescue procedures were excluded to minimize bias. Primary outcome: mean difference in best-corrected visual acuity (BCVA) at 3, 6, and 12 months postoperatively. Secondary outcomes: rates of graft primary failure, rejection, and rebubbling; other graft-related issues; mean difference in endothelial cell density; subjective visual outcomes; and patient satisfaction. RESULTS:: A total of 10 retrospective studies of moderate methodological quality were included (n = 947 eyes, 646 DMEK). BCVA was better with DMEK at all evaluated time points (0.16 logMAR at 12 months) comparing to DSAEK (0.30 logMAR; p < 0.001). DMEK had a 60% lower rate of rejection (risk ratio (RR) 0.4, 95% CI (0.24, 0.67), p = 0.0005), but required more rebubblings (RR = 2.48, 95% CI (1.32, 4.64), p = 0.005). DMEK had more primary graft failures and less endothelial cell density loss, but statistical difference was not reached. More patients were satisfied after DMEK (odds ratio = 10.29, 95% CI (3.55, 29.80), p < 0.0001). CONCLUSION:: DMEK showed better postoperative results regarding BCVA, patient satisfaction, and graft-related issues. However, the small number of studies with short follow-up times and other methodological issues prompt us to interpret these results carefully.

Sulfur Hexafluoride 20% Versus Air 100% for Anterior Chamber Tamponade in DMEK: A Meta-Analysis.

PURPOSE: To compare intracameral 20% sulfur hexafluoride (SF6) versus 100% air as tamponade for graft attachment in Descemet membrane endothelial keratoplasty (DMEK). METHODS: Using an electronic database search on MEDLINE and CENTRAL from inception to December 2017, we performed a literature review and meta-analysis including all comparative studies of SF6 at a 20% concentration (20% SF6) versus pure air (100% air) for anterior chamber tamponade in DMEK. The primary outcome was the rebubbling rate at the final observation. The secondary outcomes were 1) the graft detachment rate, 2) mean difference (MD) in best-corrected visual acuity (BCVA), 3) manifest refraction spherical equivalent, 4) central corneal thickness (CCT), 5) percentage of endothelial cell loss (ECL), and 6) rate of pupillary block by the final observation. Statistical analysis was performed using RevMan5.3 software. RESULTS: Five retrospective studies were included, assessing 1195 eyes (SF6 277; air 918). The main indication for surgery was Fuchs endothelial dystrophy (SF6 85.2%; air 86.2%) and bullous keratopathy (SF6 10.8%; air 10.0%). Overall, studies were of moderate to good methodological quality. Patients in the SF6 group required 58% less rebubbling procedures (risk ratio 0.42, 95% confidence interval (CI), 0.31-0.56, P < 0.0001). No differences were found regarding BCVA improvement (MD 0.03, 95% CI, -0.05 to 0.11, P = 0.49). SF6 was associated with a minor hyperopic shift (MD 0.37 D, 95% CI, -0.95 to -0.21, P = 0.21). No differences were found regarding CCT, ECL, and rate of pupillary block (P > 0.05). CONCLUSIONS: In DMEK, 20% SF6 tamponade and longer postoperative time supine were associated with 58% fewer rebubbling procedures, and an ECL not statistically different from using 100% air.

Padrões eletroforéticos das proteínas de reserva em grãos de sorgo com presença e ausência de tanino / Electrophoretic patterns of grain storage proteins of sorghum with presence and absence of tannin

Muitos métodos para determinar a presença de taninos são descritos na literatura, mas nenhum deles é universalmente aceito como ideal ou utilizado de forma unânime. Alguns métodos colorimétricos não diferenciam taninos de outros compostos fenólicos, outros utilizam substâncias que não são adequadas como padrão. Métodos que utilizam a capacidade dos taninos de precipitar as proteínas podem causar resultados divergentes devido às diferenças na conformação dessas moléculas. Assim, objetivou-se, neste estudo, identificar a presença de taninos em 10 híbridos de sorgo através da análise de padrões proteicos obtidos por eletroforese. O método colorimétrico Azul da Prússia foi utilizado para quantificar os taninos nas amostras. A precipitação das proteínas pelos taninos permitiu identificar os genótipos de sorgo com tanino através dos padrões proteicos das frações albuminas, globulinas e prolaminas. A análise eletroforética das prolaminas mostrou que as bandas produzidas pelo polipeptídeo kafirina, podem ser utilizadas na identificação de sorgo sem tanino no grão.

Several methods are described on the literature to determine the presence of tannin, however none of them is universally accepted as the ideal or even are used in a unanimous way. Some colorimetric methods do not differentiate tannins from others phenolic compounds, others use substances which are not appropriate to use as standard. Methods that use the capacity of tannins to precipitate proteins may end up with divergent results due to differences on the molecule conformation. Thus, the objective of this study was to identify the presence of tannin in 10 hybrids of sorghum throughout analysis of pattern proteins obtained by electrophoresis. The colored method Prussian Blue was used to quantify tannins on the samples. The protein precipitation by tannins permitted to identify the sorghum genotypes with grain tannin through protein standards of fractions of albumin, globulin and prolamins. The electrophoresis analysis of the prolamins showed that the bands produced by the kafirin polypeptide may be used in sorghum identification without the presence of tannin in grain.

Plantas medicinais utilizadas como calmantes por agricultores ecológicos da Região Sul do Rio Grande do Sul, Brasil / Medicinal plants used as sedative by ecological farmers from southern Rio Grande do Sul state, Brazil

Objetivo: identificar as plantas medicinais utilizadas como calmantes, por famílias de agricultores de base ecológica daRegião Sul do Rio Grande do Sul, Brasil. Método: a pesquisa é de abordagem qualitativa, exploratória e descritiva, sendoos dados coletados de janeiro a maio de 2009. Os sujeitos foram de oito famílias de agricultores, residentes nos municípiosde Pelotas, Morro Redondo, Canguçu e Arroio do Padre. Estudo aprovado pelo Comitê de Ética em Pesquisa da Faculdadede Medicina da Universidade Federal de Pelotas (072/2007). Resultados: encontramos citações de 196 plantas medicinais,entre nativas e exóticas, e sete elixires. Destas, doze plantas (Lactuca sativa L., Aloysia gratissima (Gillies & Hook.)Tronc., Chamomilla recutita L., Cymbopogon citratus (DC.), Aloysia triphylla Royle, Aristolochia cymbifera Mart. & Zucc.,Ageratum conyzoides L., Eucalyptus sp., Citrus sinensis (L.) Osbeck, Passiflora caerulea L., Melissa officinalis L., Cunilamicrocephala Benth.) e um elixir foram mencionados com efeito calmante. Conclusão: o enfermeiro pode atuar naorientação do uso das plantas medicinais objetivando a promoção da saúde, na prevenção e tratamento de doenças. Éfundamental a ampliação dos estudos farmacológicos em relação às plantas utilizadas pelo conhecimento popular nocuidado à saúde.