Reflection is a natural phenomenon that occurs when light passes the interface between materials with different refractive index. In many applications, such as solar cells or photodetectors, ...reflection is an unwanted loss process. Many ways to reduce reflection from a substrate have been investigated so far, including dielectric interference coatings, surface texturing, adiabatic index matching and scattering from plasmonic nanoparticles. Here we present an entirely new concept that suppresses the reflection of light from a silicon surface over a broad spectral range. A two-dimensional periodic array of subwavelength silicon nanocylinders designed to possess strongly substrate-coupled Mie resonances yields almost zero total reflectance over the entire spectral range from the ultraviolet to the near-infrared. This new antireflection concept relies on the strong forward scattering that occurs when a scattering structure is placed in close proximity to a high-index substrate with a high optical density of states.
Sufficient physical activity is important for solid organ transplant recipients (heart, lung, liver, kidney). However, recipients do not meet the recommended amount or required type of physical ...activity. The perceived barriers to and facilitators of physical activity in this population are largely unknown.
Semi-structured in depth interviews were conducted with solid organ transplant recipients in order to explore experienced barriers and facilitators. Qualitative methodology with thematic line-by-line analysis was used for analysis, and derived themes were classified into personal and environmental factors.
The most important indicated barriers were physical limitations, insufficient energy level, fear, and comorbidities. The most frequently mentioned facilitators included motivation, coping, consequences of (in)activity, routine/habit, goals/goal priority, and responsibility for the transplanted organ. Neutral factors acting as a barrier or facilitator were self-efficacy and expertise of personnel. A comparison of barriers and facilitators between transplant recipient groups yielded no overt differences.
Several personal and environmental factors were indicated that should be considered in intervention development to increase physical activity behavior in solid organ transplant recipients.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Plasmonic nanostructures have been recently investigated as a possible way to improve absorption of light in solar cells. The strong interaction of small metal nanostructures with light allows ...control over the propagation of light at the nanoscale and thus the design of ultrathin solar cells in which light is trapped in the active layer and efficiently absorbed. In this paper we review some of our recent work in the field of plasmonics for improved solar cells. We have investigated two possible ways of integrating metal nanoparticles in a solar cell. First, a layer of Ag nanoparticles that improves the standard antireflection coating used for crystalline and amorphous silicon solar cells has been designed and fabricated. Second, regular and random arrays of metal nanostructures have been designed to couple light in waveguide modes of thin semiconductor layers. Using a large-scale, relative inexpensive nano-imprint technique, we have designed a back-contact light trapping surface for a-Si:H solar cells which show enhanced efficiency over standard randomly textured cells.
The process of brain death (BD) detrimentally affects donor lung quality. Ex vivo lung perfusion (EVLP) is a technique originally designed to evaluate marginal donor lungs. Nowadays, its potential as ...a treatment platform to repair damaged donor lungs is increasingly studied in experimental models. Rat models for EVLP have been described in literature before, yet the pathophysiology of BD was not included in these protocols and prolonged perfusion over 3 hours without anti-inflammatory additives was not achieved. We aimed to establish a model for prolonged EVLP of rat lungs from brain-dead donors, to provide a reliable platform for future experimental studies. Rat lungs were randomly assigned to one of four experimental groups (n = 7/group): 1) healthy, directly procured lungs, 2) lungs procured from rats subjected to 3 hours of BD and 1 hour cold storage (CS), 3) healthy, directly procured lungs subjected to 6 hours EVLP and 4), lungs procured from rats subjected to 3 hours of BD, 1 hour CS and 6 hours EVLP. Lungs from brain-dead rats showed deteriorated ventilation parameters and augmented lung damage when compared to healthy controls, in accordance with the pathophysiology of BD. Subsequent ex vivo perfusion for 6 hours was achieved, both for lungs of healthy donor rats as for pre-injured donor lungs from brain-dead rats. The worsened quality of lungs from brain-dead donors was evident during EVLP as well, as corroborated by deteriorated ventilation performance, increased lactate production and augmented inflammatory status during EVLP. In conclusion, we established a stable model for prolonged EVLP of pre-injured lungs from brain-dead donor rats. In this report we describe tips and pitfalls in the establishment of the rat EVLP model, to enhance reproducibility by other researchers.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We demonstrate an enhanced and tailor-made directional emission of light-emitting devices using nanoimprinted hexagonal arrays of aluminum nanoparticles. Fourier microscopy reveals that the ...luminescence of the device is not only determined by the material properties of the organic dye molecules but is also strongly influenced by the coherent scattering resulting from periodically arranged metal nanoparticles. Emitters can couple to lattice-induced hybrid plasmonic-photonic modes sustained by plasmonic arrays. Such modes enhance the spatial coherence of an emitting layer, allowing the efficient beaming of the emission along narrow angular and spectral ranges. We show that tailoring the separation of the nanoparticles in the array yields an accurate angular distribution of the emission. This combination of large-area metal nanostructures fabricated by nanoimprint lithography and light-emitting devices is beneficial for the design and optimization of solid-state lighting systems.
In this study we report the clinical features of 32 patients with gamma aminobutyric acid B receptor (GABABR) antibodies, identify additional autoantibodies in patients with anti-GABABR encephalitis ...that mark the presence of an underlying small cell lung carcinoma and optimize laboratory methods for the detection of GABABR antibodies. Patients (n = 3225) were tested for the presence of GABABR antibodies using cell-based assay, immunohistochemistry and live hippocampal neurons. Clinical data were obtained retrospectively. Potassium channel tetramerization domain-containing (KCTD)16 antibodies were identified by immunoprecipitation, mass spectrometry analysis and cell-based assays. KCTD16 antibodies were identified in 23/32 patients with anti-GABABR encephalitis, and in 1/26 patients with small cell lung carcinoma and Hu antibodies, but not in 329 healthy subjects and disease controls. Of the anti-GABABR encephalitis patients that were screened sufficiently, 18/19 (95%) patients with KCTD16 antibodies had a tumour versus 3/9 (33%) anti-GABABR encephalitis patients without KCTD16 antibodies (P = 0.001). In most cases this was a small cell lung carcinoma. Patients had cognitive or behavioural changes (97%) and prominent seizures (90%). Thirteen patients developed a refractory status epilepticus with intensive care unit admittance (42%). Strikingly, 4/32 patients had a rapidly progressive dementia. The addition of KCTD16 to the GABABR cell-based assay improved sensitivity of the in-house fixed cell-based assay, without loss of specificity. Twenty-two of 26 patients improved (partially) to immunotherapy or chemotherapy. Anti-GABABR encephalitis is a limbic encephalitis with prominent, severe seizures, but patients can also present with rapidly progressive dementia. The co-occurrence of KCTD16 antibodies points towards a paraneoplastic origin. The addition of KCTD16 improves the sensitivity of the cell-based assay.
Concerns have been raised on the impact of coronavirus disease (COVID-19) on lung transplant (LTx) patients. The aim of this study was to evaluate the transplant function pre- and post-COVID-19 in ...LTx patients.
Data were retrospectively collected from LTx patients with confirmed COVID-19 from all 3 Dutch transplant centers, between February 2020 and September 2021. Spirometry results were collected pre-COVID-19, 3- and 6-months post-infection.
Seventy-four LTx patients were included. Forty-two (57%) patients were admitted, 19 (26%) to the intensive care unit. The in-hospital mortality was 20%. Twelve out of 19 ICU patients died (63%), a further 3 died on general wards. Patients with available spirometry (78% at 3 months, 65% at 6 months) showed a significant decline in mean FEV1 (ΔFEV1 138 ±39 ml, p = 0.001), and FVC (ΔFVC 233 ±74 ml, p = 0.000) 3 months post-infection. Lung function improved slightly from 3 to 6 months after COVID-19 (ΔFEV1 24 ±38 ml; ΔFVC 100 ±46 ml), but remained significantly lower than pre-COVID-19 values (ΔFEV1 86 ml ±36 ml, p = 0.021; ΔFVC 117 ±35 ml, p= 0.012). FEV1/FVC was > 0.70.
In LTx patients COVID-19 results in high mortality in hospitalized patients. Lung function declined 3 months after infection and gradually improved at 6 months, but remained significantly lower compared to pre-COVID-19 values. The more significant decline in FVC than in FEV1 and FEV1/FVC > 70%, suggested a more restrictive pattern.
We demonstrate a soft-imprint nanofabrication technique offering nanometer resolution over an area as large as a 150 mm diameter wafer. It makes use of a composite imprint stamp composed of a ...quaternary siloxane-modified poly-di-methyl-siloxane patterned rubber layer with a relatively high Young's modulus that is laminated on a thin glass support. The in-plane stiffness of the stamp avoids pattern deformation over large areas, while out-of-plane flexibility allows conformal contact to be made over the entire substrate area. The stamp is used in conjunction with a novel tetra-methyl-ortho-siloxane/methyl-tri-methoxy-siloxane sol-gel imprint resist material developed to replicate nanoscale features in rigid silica at room temperature. We demonstrate better than 10 nm resolution in imprinted line gratings and individual pillars with aspect ratio as high as 5:1. Gaps as small as 6 nm can be reproduced. The patterns can be used as an etch mask to pattern 150 mm diameter silicon and quartz substrates while maintaining sub-10 nm resolution.
Background
Coronavirus disease 2019 (COVID-19) social distancing measures led to a dramatic decline in non-COVID-19 respiratory virus infections, providing a unique opportunity to study their impact ...on annual forced expiratory volume in 1 s (FEV
1
) decline, episodes of temporary drop in lung function (TDLF) suggestive of infection and chronic lung allograft dysfunction (CLAD) in lung transplant recipients (LTRs).
Methods
All FEV
1
values of LTRs transplanted between 2009 and April 2020 at the University Medical Center Groningen (Groningen, The Netherlands) were included. Annual FEV
1
change was estimated with separate estimates for pre-social distancing (2009–2020) and the year with social distancing measures (2020–2021). Patients were grouped by individual TDLF frequency (frequent/infrequent). Respiratory virus circulation was derived from weekly hospital-wide respiratory virus infection rates. Effect modification by TDLF frequency and respiratory virus circulation was assessed. CLAD and TDLF rates were analysed over time.
Results
479 LTRs (12 775 FEV
1
values) were included. Pre-social distancing annual change in FEV
1
was −114 (95% CI −133– −94) mL, while during social distancing FEV
1
did not decline: 5 (95% CI −38–48) mL (difference pre-social distancing
versus
during social distancing: p<0.001). The frequent TDLF subgroup showed faster annual FEV
1
decline compared with the infrequent TDLF subgroup (−150 (95% CI −181– −120)
versus
−90 (95% CI −115– −65) mL; p=0.003). During social distancing, we found significantly lower odds for any TDLF (OR 0.53, 95% CI 0.33–0.85; p=0.008) and severe TDLF (OR 0.34, 0.16–0.71; p=0.005) as well as lower CLAD incidence (OR 0.53, 95% CI 0.27–1.02; p=0.060). Effect modification by respiratory virus circulation indicated a significant association between TDLF/CLAD and respiratory viruses.
Conclusions
During COVID-19 social distancing the strong reduction in respiratory virus circulation coincided with markedly less FEV
1
decline, fewer episodes of TDLF and possibly less CLAD. Effect modification by respiratory virus circulation suggests an important role for respiratory viruses in lung function decline in LTRs.
Short-term survival after solid-organ transplantation has substantially improved, and the focus has shifted to long-term survival, including the role of physical activity (PA). Knowledge about PA and ...sedentary time in recipients of solid-organ transplantation is limited, and identification of the levels and associated factors is necessary for intervention development.
The objectives of this study were to investigate the level of PA and sedentary time in recipients of solid-organ transplantation and to identify factors associated with these behaviors.
The design consisted of a cross-sectional survey.
Questionnaires on PA level, sedentary time, and potential associated factors were used for recipients of solid-organ transplantation (kidney, liver, lung, and heart N = 656). Multiple regression analyses with a variable selection procedure were used.
Fewer than 60% of the recipients fulfilled the PA guideline. Factors significantly associated with a lower level of PA included being a woman, younger age (nonlinear), not actively working or being retired, physical limitations, and low expectations and self-confidence. Factors significantly associated with less sedentary time included exercise self-efficacy and not actively working or being retired. Significantly associated with more sedentary time were a high education level, fear of negative effects, physical limitations, and the motivator "health and physical outcomes." The type of transplantation did not significantly influence either of the outcome measures.
The design did not allow for causal inferences to be made. The studied associated factors were limited to individual and interpersonal factors. Self-reported measures of PA and sedentary time were used.
In intervention development directed at increasing the level of PA and reducing sedentary time in recipients of solid-organ transplantation, attention should be paid to physical limitations, fear of negative effects, low expectations and self-confidence, health and physical outcomes, and exercise self-efficacy.
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