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1.
Front Immunol ; 13: 916686, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35784346

RESUMO

Antibody response following Omicron infection is reported to be less robust than that to other variants. Here we investigated how prior vaccination and/or prior infection modulates that response. Disease severity, antibody responses and immune transcriptomes were characterized in four groups of Omicron-infected outpatients (n=83): unvaccinated/no prior infection, vaccinated/no prior infection, unvaccinated/prior infection and vaccinated/prior infection. The percentage of patients with asymptomatic or mild disease was highest in the vaccinated/no prior infection group (87%) and lowest in the unvaccinated/no prior infection group (47%). Significant anti-Omicron spike antibody levels and neutralizing activity were detected in the vaccinated group immediately after infection but were not present in the unvaccinated/no prior infection group. Within two weeks, antibody levels against Omicron, increased. Omicron neutralizing activity in the vaccinated group exceeded that of the prior infection group. No increase in neutralizing activity in the unvaccinated/no prior infection group was seen. The unvaccinated/prior infection group showed an intermediate response. We then investigated the early transcriptomic response following Omicron infection in these outpatient populations and compared it to that found in unvaccinated hospitalized patients with Alpha infection. Omicron infected patients showed a gradient of transcriptional response dependent upon whether or not they were previously vaccinated or infected. Vaccinated patients showed a significantly blunted interferon response as compared to both unvaccinated Omicron infected outpatients and unvaccinated Alpha infected hospitalized patients typified by the response of specific gene classes such as OAS and IFIT that control anti-viral responses and IFI27, a predictor of disease outcome.


Assuntos
Imunidade Humoral , Pacientes Ambulatoriais , Anticorpos Antivirais , Humanos , Vacinação
2.
Artigo em Inglês | MEDLINE | ID: mdl-35465056

RESUMO

Background: SARS-CoV-2 infection activates interferon-controlled signaling pathways and elicits a wide spectrum of immune responses and clinical manifestations in human patients. Methods: Here, we investigate the impact of prior vaccination on the innate immune response of hospitalized COVID-19 patients infected with the SARS-CoV-2 Beta variant through RNA sequencing of peripheral blood immune cells. Four patients had received the first dose of BNT162b2 about 11 days prior to the onset of COVID-19 symptoms and five patients were unvaccinated. Patients had received dexamethasone treatment. Immune transcriptomes were obtained at days 7-13, 20-32 and 42-60 after first symptomology. Results: RNA-seq reveals an enhanced JAK-STAT-mediated immune transcriptome response at day 10 in vaccinated patients as compared to unvaccinated ones. This increase subsides by day 35. Expression of the gene encoding the antiviral protein oligoadenylate synthetase (OAS) 1, which is inversely correlated with disease severity, and other key antiviral proteins increases in the vaccinated group. We also investigate the immune transcriptome in naïve individuals receiving their first dose of BNT162b2 and identify a gene signature shared with the vaccinated COVID-19 patients. Conclusions: Our study demonstrates that RNA-seq can be used to monitor molecular immune responses elicited by the BNT162b2 vaccine, both in naïve individuals and in COVID-19 patients, and it provides a biomarker-based approach to systems vaccinology.

3.
Sci Rep ; 12(1): 2784, 2022 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-35181735

RESUMO

Fast-spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) energize the COVID-19 pandemic. While viral infections elicit a conserved immune response, it is not known whether SARS-CoV-2 variants, which display enhanced binding to the ACE2 receptor and reduced neutralizing activity by vaccine-elicited antibodies, prompt specific genomic immune responses. To test this, we generated and investigated the transcriptomes in BCs from hospitalized patients infected with either the Alpha variant (n = 36) or with the Alpha variant that had acquired the E484K escape mutation (Alpha+E484K) (n = 13). We identified a gene module preferentially activated in patients infected with the Alpha+E484K variant and in patients infected with the Beta (n = 9) and Gamma (n = 3) variants that also carry by the E484K escape mutation. The E484K signature was enriched for genes preferentially expressed in monocytes and linked to severe viral infection. However, both cohorts had undergone similar treatments and no differences in disease severity were reported suggesting that this signature reflects a variant response and does not necessarily associate with disease outcome. Additionally, longitudinal transcriptome analyses revealed a more persistent retention of immune signatures in Alpha+E484K patients throughout the entire course of COVID-19 disease and convalescence. While the OAS1 Neanderthal mutation has been linked to a milder COVID-19 pathology, we did not identify significant immune transcriptomes differences in the 25 patients homozygous for this mutation. Our study offers insights into distinct molecular immune responses elicited by SARS-CoV-2 variants carrying the E484K escape mutation throughout the COVID-19 disease.


Assuntos
COVID-19/imunologia , Redes Reguladoras de Genes , SARS-CoV-2/genética , Transcriptoma , 2',5'-Oligoadenilato Sintetase/genética , Adulto , Idoso , COVID-19/genética , COVID-19/virologia , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Adulto Jovem
4.
Opt Express ; 29(13): 19472-19485, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34266056

RESUMO

The fabrication of highly reflective aluminum coatings is still an important part of current research due to their high intrinsic reflectivity in a broad spectral range. By using thin seed layers of Cu, CuOx, Cr, CrOx, Au, and Ag, the morphology of sputtered (unprotected) aluminum layers and, consequently, their reflectance can be influenced. In this long-term study, the reflectance behavior was measured continuously using spectrophotometry. Particular seed layer materials enhance the reflectance of aluminum coatings significantly and reduce their long-term degradation. Combining such seed layers with evaporation processes and suitable protective layers could further increase the reflectance of aluminum coatings.

5.
Res Sq ; 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34100009

RESUMO

Fast-spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) energize the COVID-19 pandemic. The B.1.351 variant carrying the escape mutation E484K in the receptor binding domain is of particular concern due to reduced immunological protection following vaccination. Protection can manifest as early as 10 days following immunization with full protection two weeks following the second dose, but the course is not well-characterized for variants. Here, we investigated the immune transcriptome of six elderly individuals (average age 82 yr.) from an old people’s home, who contracted B.1.351, with four having received the first dose of BNT162b eight to 11 days prior to the onset of COVID-19 symptoms. The patients were hospitalized and received dexamethasone treatment. Immune transcriptomes were established from PBMCs approximately 10 and 35 days after the onset of COVID-19 symptomology. RNA-seq revealed a more intensive immune response in vaccinated patients as compared to unvaccinated ones. Specifically, transcription factors linked to the JAK/STAT pathway, interferon stimulated genes, and genes associated with innate antiviral immunity and COVID-19-SARS-CoV-2 infection were highly enriched in vaccinated patients. This rendered the transcriptomes of the older vaccinated group significantly different than older unvaccinated individuals infected at the same institution and more similar to the immune response of younger unvaccinated individuals (ages 48-62) following B.1.351 infection. All individuals in this study whether vaccinated or not were hospitalized due to B.1.351 infection and one vaccinated patient died illustrating that although an enhanced immune response was documented infection it was insufficient to protect from disease. This highlights the need for maintaining physical distancing and prevention measures throughout the time course of vaccination in older adults.

6.
medRxiv ; 2021 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-34100027

RESUMO

Fast-spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) energize the COVID-19 pandemic. B.1.1.7 (VOC-202012/01) has become the predominant variant in many countries and a new lineage (VOC-202102/02) harboring the E484K escape mutation in the B.1.1.7 background emerged in February 2021 1 . This variant is of concern due to reduced neutralizing activity by vaccine-elicited antibodies 2,3 . However, it is not known whether this single amino acid change leads to an altered immune response. Here, we investigate differences in the immune transcriptome in hospitalized patients infected with either B.1.1.7 (n=28) or B.1.1.7+E484K (n=12). RNA-seq conducted on PBMCs isolated within five days after the onset of COVID symptoms demonstrated elevated activation of specific immune pathways, including JAK-STAT signaling, in B.1.1.7+E484K patients as compared to B.1.1.7. Longitudinal transcriptome studies demonstrated a delayed dampening of interferon-activated pathways in B.1.1.7+E484K patients. Prior vaccination with BNT162b vaccine (n=8 one dose; n=1 two doses) reduced the transcriptome inflammatory response to B.1.1.7+E484K infection relative to unvaccinated patients. Lastly, the immune transcriptome of patients infected with additional variants (B.1.258, B.1.1.163 and B.1.7.7) displayed a reduced activation compared to patients infected with B.1.1.7. Acquisition of the E484K substitution in the B.1.1.7 background elicits an altered immune response, which could impact disease progression.

7.
Lancet Respir Med ; 9(8): 863-872, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34126053

RESUMO

BACKGROUND: SARS-CoV-2 entry in human cells depends on angiotensin-converting enzyme 2, which can be upregulated by inhibitors of the renin-angiotensin system (RAS). We aimed to test our hypothesis that discontinuation of chronic treatment with ACE-inhibitors (ACEIs) or angiotensin II receptor blockers (ARBs) mitigates the course o\f recent-onset COVID-19. METHODS: ACEI-COVID was a parallel group, randomised, controlled, open-label trial done at 35 centres in Austria and Germany. Patients aged 18 years and older were enrolled if they presented with recent symptomatic SARS-CoV-2 infection and were chronically treated with ACEIs or ARBs. Patients were randomly assigned 1:1 to discontinuation or continuation of RAS inhibition for 30 days. Primary outcome was the maximum sequential organ failure assessment (SOFA) score within 30 days, where death was scored with the maximum achievable SOFA score. Secondary endpoints were area under the death-adjusted SOFA score (AUCSOFA), mean SOFA score, admission to the intensive care unit, mechanical ventilation, and death. Analyses were done on a modified intention-to-treat basis. This trial is registered with ClinicalTrials.gov, NCT04353596. FINDINGS: Between April 20, 2020, and Jan 20, 2021, 204 patients (median age 75 years [IQR 66-80], 37% females) were randomly assigned to discontinue (n=104) or continue (n=100) RAS inhibition. Within 30 days, eight (8%) of 104 died in the discontinuation group and 12 (12%) of 100 patients died in the continuation group (p=0·42). There was no significant difference in the primary endpoint between the discontinuation and continuation group (median [IQR] maximum SOFA score 0·00 (0·00-2·00) vs 1·00 (0·00-3·00); p=0·12). Discontinuation was associated with a significantly lower AUCSOFA (0·00 [0·00-9·25] vs 3·50 [0·00-23·50]; p=0·040), mean SOFA score (0·00 [0·00-0·31] vs 0·12 [0·00-0·78]; p=0·040), and 30-day SOFA score (0·00 [10-90th percentile, 0·00-1·20] vs 0·00 [0·00-24·00]; p=0·023). At 30 days, 11 (11%) in the discontinuation group and 23 (23%) in the continuation group had signs of organ dysfunction (SOFA score ≥1) or were dead (p=0·017). There were no significant differences for mechanical ventilation (10 (10%) vs 8 (8%), p=0·87) and admission to intensive care unit (20 [19%] vs 18 [18%], p=0·96) between the discontinuation and continuation group. INTERPRETATION: Discontinuation of RAS-inhibition in COVID-19 had no significant effect on the maximum severity of COVID-19 but may lead to a faster and better recovery. The decision to continue or discontinue should be made on an individual basis, considering the risk profile, the indication for RAS inhibition, and the availability of alternative therapies and outpatient monitoring options. FUNDING: Austrian Science Fund and German Center for Cardiovascular Research.


Assuntos
Antagonistas de Receptores de Angiotensina , Inibidores da Enzima Conversora de Angiotensina , COVID-19 , Hipertensão , Sistema Renina-Angiotensina , SARS-CoV-2 , Antagonistas de Receptores de Angiotensina/administração & dosagem , Antagonistas de Receptores de Angiotensina/efeitos adversos , Enzima de Conversão de Angiotensina 2/metabolismo , Inibidores da Enzima Conversora de Angiotensina/administração & dosagem , Inibidores da Enzima Conversora de Angiotensina/efeitos adversos , Área Sob a Curva , COVID-19/epidemiologia , COVID-19/metabolismo , COVID-19/terapia , Feminino , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/epidemiologia , Masculino , Pessoa de Meia-Idade , Escores de Disfunção Orgânica , Avaliação de Processos e Resultados em Cuidados de Saúde , Sistema Renina-Angiotensina/efeitos dos fármacos , Sistema Renina-Angiotensina/fisiologia , Risco Ajustado/métodos , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/fisiologia , Índice de Gravidade de Doença , Suspensão de Tratamento/estatística & dados numéricos
8.
medRxiv ; 2021 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-34013280

RESUMO

Fast-spreading variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) energize the COVID-19 pandemic. The B.1.351 variant carrying the escape mutation E484K in the receptor binding domain is of particular concern due to reduced immunological protection following vaccination. Protection can manifest as early as 10 days following immunization with full protection two weeks following the second dose, but the course is not well-characterized for variants. Here, we investigated the immune transcriptome of six elderly individuals (average age 82 yr.) from an old people's home, who contracted B.1.351, with four having received the first dose of BNT162b eight to 11 days prior to the onset of COVID-19 symptoms. The patients were hospitalized and received dexamethasone treatment. Immune transcriptomes were established from PBMCs approximately 10 and 35 days after the onset of COVID-19 symptomology. RNA-seq revealed a more intensive immune response in vaccinated patients as compared to unvaccinated ones. Specifically, transcription factors linked to the JAK/STAT pathway, interferon stimulated genes, and genes associated with innate antiviral immunity and COVID-19-SARS-CoV-2 infection were highly enriched in vaccinated patients. This rendered the transcriptomes of the older vaccinated group significantly different than older unvaccinated individuals infected at the same institution and more similar to the immune response of younger unvaccinated individuals (age range 48-62) following B.1.351 infection. All individuals in this study whether vaccinated or not were hospitalized due to B.1.351 infection and one vaccinated patient died illustrating that although an enhanced immune response was documented infection it was insufficient to protect from disease. This highlights the need for maintaining physical distancing and prevention measures throughout the time course of vaccination in older adults.

9.
Sci Rep ; 11(1): 4243, 2021 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-33608566

RESUMO

SARS-CoV-2 infection ranges from asymptomatic to severe with lingering symptomatology in some. This prompted investigation of whether or not asymptomatic disease results in measurable immune activation post-infection. Immune activation following asymptomatic SARS-CoV-2 infection was characterized through a comparative investigation of the immune cell transcriptomes from 43 asymptomatic seropositive and 52 highly exposed seronegative individuals from the same community 4-6 weeks following a superspreading event. Few of the 95 individuals had underlying health issues. One seropositive individual reported Cystic Fibrosis and one individual reported Incontinentia pigmenti. No evidence of immune activation was found in asymptomatic seropositive individuals with the exception of the Cystic Fibrosis patient. There were no statistically significant differences in immune transcriptomes between asymptomatic seropositive and highly exposed seronegative individuals. Four positive controls, mildly symptomatic seropositive individuals whose blood was examined 3 weeks following infection, showed immune activation. Negative controls were four seronegative individuals from neighboring communities without COVID-19. All individuals remained in their usual state of health through a five-month follow-up after sample collection. In summary, whole blood transcriptomes identified individual immune profiles within a community population and showed that asymptomatic infection within a super-spreading event was not associated with enduring immunological activation.


Assuntos
COVID-19/imunologia , SARS-CoV-2/imunologia , Transcriptoma/imunologia , Imunidade Adaptativa/genética , Adolescente , Adulto , Idoso , Anticorpos Antivirais/sangue , Anticorpos Antivirais/isolamento & purificação , Infecções Assintomáticas , Áustria , COVID-19/sangue , COVID-19/diagnóstico , COVID-19/transmissão , Teste Sorológico para COVID-19/estatística & dados numéricos , Criança , Pré-Escolar , Busca de Comunicante/estatística & dados numéricos , Características da Família , Feminino , Seguimentos , Interações entre Hospedeiro e Microrganismos/genética , Interações entre Hospedeiro e Microrganismos/imunologia , Humanos , Imunidade Inata/genética , Lactente , Masculino , Pessoa de Meia-Idade , RNA-Seq/estatística & dados numéricos , SARS-CoV-2/isolamento & purificação , Adulto Jovem
10.
medRxiv ; 2020 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-32908998

RESUMO

To investigate prevalence of ongoing activation of inflammation following asymptomatic SARS-CoV-2 infection we characterized immune cell transcriptomes from 43 asymptomatic seropositive and 52 highly exposed seronegative individuals with few underlying health issues following a community superspreading event. Four mildly symptomatic seropositive individuals examined three weeks after infection as positive controls demonstrated immunological activation. Approximately four to six weeks following the event, the two asymptomatic groups showed no significant differences. Two seropositive patients with underlying genetic disease impacting immunological activation were included (Cystic Fibrosis (CF), Nuclear factor-kappa B Essential Modulator (NEMO) deficiency). CF, but not NEMO, associated with significant immune transcriptome differences including some associated with severe SARS-CoV-2 infection (IL1B, IL17A, respective receptors). All subjects remained in their usual state of health from event through five-month follow-up. Here, asymptomatic infection resolved without evidence of prolonged immunological activation. Inclusion of subjects with underlying genetic disease illustrated the pathophysiological importance of context on impact of immunological response.

11.
Res Sq ; 2020 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-32995765

RESUMO

To investigate prevalence of ongoing activation of inflammation following asymptomatic SARS-CoV-2 infection we characterized immune cell transcriptomes from 43 asymptomatic seropositive and 52 highly exposed seronegative individuals with few underlying health issues following a community superspreading event. Four mildly symptomatic seropositive individuals examined three weeks after infection as positive controls demonstrated immunological activation. Approximately four to six weeks following the event, the two asymptomatic groups showed no significant differences. Two seropositive patients with underlying genetic disease impacting immunological activation were included (Cystic Fibrosis (CF), Nuclear factor-kappa B Essential Modulator (NEMO) deficiency). CF, but not NEMO, associated with significant immune transcriptome differences including some associated with severe SARS-CoV-2 infection (IL1B, IL17A, respective receptors). All subjects remained in their usual state of health from event through five-month follow-up. Here, asymptomatic infection resolved without evidence of prolonged immunological activation. Inclusion of subjects with underlying genetic disease illustrated the pathophysiological importance of context on impact of immunological response.

12.
Appl Opt ; 54(16): 4966-71, 2015 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-26192652

RESUMO

In the visible to infrared spectral range, highly-reflective silver mirrors are applied in the manufacture of optical instruments such as telescopes. However, it is still difficult to combine high reflectivity and long-term stability of the protected silver coating. We show that the deposition of impervious protective layers is necessary but often not sufficient for long-term environmental stability. Hygroscopic air borne particles absorbed by the protections surface attract water molecules and form a solution. This solution first damages the protection, subsequently permeates the protection and finally damages the silver whereby the reflectivity is reduced. We demonstrate this particular damage mechanism with different experiments and describe this mechanism in detail.

13.
Opt Express ; 23(4): 4289-95, 2015 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-25836465

RESUMO

In this paper, the authors report on La/B(4)C multilayer mirrors designed for an incidence angle of 45° with both maximum reflectivity at a wavelength of 6.7 nm and reflectivity suppression at a wavelength of 20.1 nm. These mirrors were deposited for the EIS-TIMER at the FERMI@Elettra Free Electron Laser. The multilayer structure and optical properties were characterized using grazing incidence X-ray reflectometry with Cu-K(α) radiation and EUV reflectometry in the spectral region of 6.5 - 21.0 nm. An anti-reflective coating designed at the wavelength of 20.1 nm had to be deposited on top of the high reflective La/B(4)C multilayer mirror optimized at a wavelength of 6.7 nm. Measured reflectivities of 53.4% at the wavelength of 6.72 nm and 0.15% at the wavelength of 20.1 nm were simultaneously achieved. It is shown that the reflectivity loss at the wavelength of 6.7 nm due to the utilization of antireflective coating designed at the wavelength of 20.1 nm can be minimized up to 1.0%.

14.
Lancet Neurol ; 14(1): 48-56, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25435129

RESUMO

BACKGROUND: Intravenous thrombolysis for ischaemic stroke remains underused worldwide. We aimed to assess whether our statewide comprehensive stroke management programme would improve thrombolysis use and clinical outcome in patients. METHODS: In 2008-09, we designed the Tyrol Stroke Pathway, which provided information campaigns for the public and standardised the entire treatment pathway from stroke onset to outpatient rehabilitation. It was commenced in Tyrol, Austria, as a long-term routine-care programme and aimed to include all patients with stroke in the survey area. We focused on thrombolysis use and outcome in the first full 4 years of implementation (2010-13). FINDINGS: We enrolled 4947 (99%) of 4992 patients with ischaemic stroke who were admitted to hospitals in Tyrol; 675 (14%) of the enrollees were treated with alteplase. Thrombolysis administration in Tyrol increased after programme implementation, from 160 of 1238 patients (12·9%, 95% CI 11·1-14·9) in 2010 to 213 of 1266 patients (16·8%, 14·8-19·0) in 2013 (ptrend 2010-13<0·0001). Differences in use of thrombolysis in the nine counties of Tyrol in 2010 (range, 2·2-22·6%) were reduced by 2013 (12·1-22·5%). Median statewide door-to-needle time decreased from 49 min (IQR 35-60) in 2010 to 44 min (29-60) in 2013; symptomatic post-thrombolysis intracerebral haemorrhages occurred in 28 of 675 patients (4·1%, 95% CI 2·8-5·9) during 2010-13. In four Austrian states without similar stroke programmes, thrombolysis administration remained stable or declined between 2010 and 2013 (mean reduction 14·4%, 95% CI 10·9-17·9). Although the 3-month mortality was not affected by our programme (137 [13%] of 1060 patients in 2010 vs 143 [13%] of 1069 patients in 2013), 3-month functional outcome significantly improved (modified Rankin Scale score 0-1 in 375 [40%] of 944 patients in 2010 vs 493 [53%] of 939 in 2013; score 0-2 in 531 [56%] patients in 2010 and 615 [65%] in 2013; ptrend 2010-13<0·0001). INTERPRETATION: During the period of implementation of our comprehensive stroke management programme, thrombolysis administration increased and clinical outcome significantly improved, although mortality did not change. We hope that these results will guide health authorities and stroke physicians elsewhere when implementing similar programmes for patients with stroke. FUNDING: Reformpool of the Tyrolean Health Care Fund.


Assuntos
Fibrinolíticos/farmacologia , Programas Governamentais/estatística & dados numéricos , Acidente Vascular Cerebral/tratamento farmacológico , Terapia Trombolítica/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Áustria/epidemiologia , Feminino , Fibrinolíticos/administração & dosagem , Humanos , Masculino , Estudos Retrospectivos , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/mortalidade , Ativador de Plasminogênio Tecidual/administração & dosagem , Ativador de Plasminogênio Tecidual/farmacologia , Resultado do Tratamento
15.
Appl Opt ; 51(19): 4436-47, 2012 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-22772117

RESUMO

Copper island films have been prepared by thermal evaporation in vacuum and characterized by in situ as well as ex situ spectrophotometry. The parallel investigation of the island morphology by means of transmission electron microscopy allowed us to establish a clear correlation between film structure and optical properties. The effective optical constants of the copper island films could be determined by means of a fit of their ex situ transmission and reflection spectra. The effective optical constants have been used for designing and preparing optical multilayer coatings applicable for attenuator or color filter specifications. Measured characteristics of the multilayer coatings are in very good agreement with the calculated spectra.

16.
Appl Opt ; 50(9): C232-8, 2011 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-21460944

RESUMO

We realized metal fluoride coatings with a high packing density and a low extinction coefficient by plasma (ion)-assisted deposition. The densification can be performed by different types of plasma sources, e.g., by a Leybold LION source and a Leybold APSpro, respectively. But the as-deposited coatings show a characteristic absorption behavior, whereas the absorption losses can be reduced in a postdeposition UV treatment step. We show experimental results of the plasma-assisted metal fluorides before and after the UV treatment and present a new model that allows us to describe and calculate the characteristic absorption losses of LaF3, MgF2, and AlF3.

17.
Appl Opt ; 50(9): C253-6, 2011 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-21460948

RESUMO

Antireflective coatings on sapphire were optimized by variation of the coating design, the total thickness, and the highly refractive material used. The coatings were characterized with a focus on their scratch resistance. An increased resistance against scratching wear is shown for hafnia-containing coatings with a total thickness of about 500 nm.

18.
Appl Opt ; 50(9): C31-5, 2011 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-21460957

RESUMO

Organic layers can be used to realize special functions in optical interference coatings. Suitable compounds for such layers were thermally evaporated and characterized. A plasma etching procedure was applied to produce nanostructures on top of the organic layers to reduce their effective refractive indices. Broadband antireflective coatings were obtained by combining these artificial low-index layers with conventionally prepared interference stacks.

19.
Appl Opt ; 50(9): C5-10, 2011 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-21460981

RESUMO

The combination of in situ spectrophotometry during film deposition and ex situ spectrophotometry allows insight into the depth distribution of optical losses in plasma ion assisted deposition coatings. An adapted optical characterization strategy for absorbing coatings using only in situ transmittance data has been developed and is exemplified in application to magnesium fluoride coatings. Measurements and simulation results strongly indicate an increased absorption caused by local understoichiometry of the fluoride material close to the fused silica substrate.

20.
Appl Opt ; 50(9): C69-74, 2011 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-21460985

RESUMO

Material mixtures offer new possibilities for synthesizing coating materials with tailored optical and mechanical properties. We present experimental results on mixtures of HfO2, ZrO2, and Al2O3, pursuing applications in UV coating technology, while the mixtures are prepared by magnetron sputtering, ion beam sputtering, plasma ion-assisted deposition (PIAD), and electron beam evaporation without assistance. The properties investigated include the refractive index, optical gap, thermal shift, and mechanical stress. The first high reflectors for UV applications have been deposited by PIAD.

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