Label-Free Complete Absorption Microscopy Using Second Generation Photoacoustic Remote Sensing

In the past decades, absorption modalities have emerged as powerful tools for label-free functional and structural imaging of cells and tissues. Many biomolecules present unique absorption spectra providing chromophore-specific information on properties such as chemical bonding, and sample composition. As chromophores absorb photons the absorbed energy is emitted as photons (radiative relaxation) or converted to heat and under specific conditions pressure (non-radiative relaxation). Modalities like fluorescence microscopy may capture radiative relaxation to provide contrast, while modalities like photoacoustic microscopy may leverage non-radiative heat and pressures. Here we show an all-optical non-contact total-absorption photoacoustic remote sensing (TA-PARS) microscope, which can capture both radiative and non-radiative absorption effects in a single acquisition. The TA-PARS yields an absorption metric proposed as the quantum efficiency ratio (QER), which visualizes a biomolecules proportional radiative and non-radiative absorption response. The TA-PARS provides label-free visualization of a range of biomolecules enabling convincing analogues to traditional histochemical staining of tissues, effectively providing label-free Hematoxylin and Eosin (H&E)-like visualizations. These findings represent the establishment of an effective all-optical non-contact total-absorption microscope for label-free inspection of biological media.

On the line shape of the total rovibronic absorption in laser-dressed diatomic molecules

Recently, the rovibronic absorption and emission spectra of diatomic molecules dressed by medium-intensity laser fields have been discussed. By computing the total absorption probability as a function of dressing wavelength an asymmetric line shape has been obtained strongly resembling to the well-known Fano line shape. Applying two-state analytical and three-state numerical models the shape of the total absorption probability function is explained. Further confirmation of the model based results is provided by high resolution accurate numerical computations using large number of basis functions.

Pengaruh Komposisi Larutan Pulsing dan Lama Perendaman Terhadap Kesegaran Bunga Potong Mawar Putih (Rosa Hybride L.) Selama Penyimpanan

ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh dan mendapatkan perlakuan yang terbaik dari larutan pulsing dan lama perendaman sebagai larutan perendam untuk memperpanjang masa kesegaran bunga potong Mawar Putih (Rosa hybrida L.). Penelitian ini menggunakan metode Rancangan Acak Lengkap (RAL) dengan dua faktor percobaan. Faktor pertama adalah komponen larutan pulsing terdiri 3 bagian yaitu: Sukrosa 5% + 250 ppm AgNO3 + Asam Sitrat 75 ppm, Sukrosa 10% + 500 ppm AgNO3 + Asam Sitrat 150 ppm dan Sukrosa 15% + 650 ppm AgNO3 + Asam Sitrat 300 ppm. Faktor kedua adalah lama perendaman terdiri dua bagian yaitu: 4 jam dan 8 jam. Analisa dilakukan setiap dua hari sekali dengan penggantian air setiap dua hari sekali yang disimpan dalam suhu ruang (27±1)0C selama 12 hari. Kombinasi perlakuan larutan pulsing dan lama perendaman berpengaruh sangat nyata (p<0,01) terhadapan serapan total serta tidak berpengaruh nyata (p>0,05) terhadap perubahan berat, uji skor warna, kelayuan, bent neck dan tingkat kemekaran. Kombinasi perlakuan terbaik adalah larutan pulsing Sukrosa 15% + 650 ppm AgNO3 + Asam Sitrat 300 ppm dengan lama perendaman 8 jam menghasilkan rata-rata serapan total 10,48 ml, rata-rata perubahan berat 9,8%, rata-rata uji skor warna 3,2, rata-rata uji skor tingkat kelayuan 3,6, rata-rata uji skor bent neck 3,6 dan rata-rata tingkat kemekaran bunga 63,89%. ABSTRACT The research aims to determine the effect of pulsing solutions and soaking time to extend the freshness of the white roses cut flower (Rosa hybrida L.) as well as to obtain the best treatments combination of the two variables. The research consists of 8 treatment combinations, each treatment was repeated 3 times to obtain 24 treatments. The research uses a completely randomized design (CRD) method with two experiment factors. The first factor is the component of the pulsing solution consisting of 3 parts: Sucrose 5% + 250 ppm AgNO3 + Citric Acid 75 ppm, Sucrose 10% + 500 ppm AgNO3 + Citric Acid 150 ppm and Sucrose 15% + 650 ppm AgNO3 + Citric Acid 300 ppm. The second factor is the immersion time consists of two parts, namely: 4 hours and 8 hours. The analysis was carried out every two days with replacement of water every two days stored at room temperature (27 ± 1)0C for 12 days. The combination of pulsing solution treatment and soaking time had a very significant effect (p<0.01) on the total absorption and had no significant effect (p>0,05) on changes in weight, color score test, withered, bent neck, and efflorescence of level. The best combination of treatments solution pulsing treatment is 15% sucrose + 650 ppm AgNO3 + 300 ppm Citric Acid with 8 hours immersion resulting in an average total absorption of 10,48 ml, an average rate of weight changes 9,8 %, the average color test score was 3.2, the average wilt level test score was 3.6, the average bent neck test score was 3.6 and average rate of flowering 63,89%. It can be concluded that white roses are affected by the concentration of the pulsing solution because the concentration of the pulsing solution gives changes to white rose cut flowers.

Source-specific light absorption by carbonaceous components in the complex aerosol matrix from yearly filter-based measurements

Understanding the sources of light-absorbing organic (brown) carbon (BrC) and its interaction with black carbon (BC) and other non-refractory particulate matter (NR-PM) fractions is important for reducing uncertainties in the aerosol direct radiative forcing. In this study, we combine multiple filter-based techniques to achieve long-term, spectrally resolved, source- and species-specific atmospheric absorption closure. We determine the mass absorption efficiency (MAE) in dilute bulk solutions at 370 nm to be equal to 1.4 m2 g−1 for fresh biomass smoke, 0.7 m2 g−1 for winter-oxygenated organic aerosol (OA), and 0.13 m2 g−1 for other less absorbing OA. We apply Mie calculations to estimate the contributions of these fractions to total aerosol absorption. While enhanced absorption in the near-UV has been traditionally attributed to primary biomass smoke, here we show that anthropogenic oxygenated OA may be equally important for BrC absorption during winter, especially at an urban background site. We demonstrate that insoluble tar balls are negligible in residential biomass burning atmospheric samples of this study and thus could attribute the totality of the NR-PM absorption at shorter wavelengths to methanol-extractable BrC. As for BC, we show that the mass absorption cross-section (MAC) of this fraction is independent of its source, while we observe evidence for a filter-based lensing effect associated with the presence of NR-PM components. We find that bare BC has a MAC of 6.3 m2 g−1 at 660 nm and an absorption Ångström exponent of 0.93 ± 0.16, while in the presence of coatings its absorption is enhanced by a factor of ∼ 1.4. Based on Mie calculations of closure between observed and predicted total light absorption, we provide an indication for a suppression of the filter-based lensing effect by BrC. The total absorption reduction remains modest, ∼ 10 %–20 % at 370 nm, and is restricted to shorter wavelengths, where BrC absorption is significant. Overall, our results allow an assessment of the relative importance of the different aerosol fractions to the total absorption for aerosols from a wide range of sources and atmospheric ages. When integrated with the solar spectrum at 300–900 nm, bare BC is found to contribute around two-thirds of the solar radiation absorption by total carbonaceous aerosols, amplified by the filter-based lensing effect (with an interquartile range, IQR, of 8 %–27 %), while the IQR of the contributions by particulate BrC is 6 %–13 % (13 %–20 % at the rural site during winter). Future studies that will directly benefit from these results include (a) optical modelling aiming at understanding the absorption profiles of a complex aerosol composed of BrC, BC and lensing-inducing coatings; (b) source apportionment aiming at understanding the sources of BC and BrC from the aerosol absorption profiles; (c) global modelling aiming at quantifying the most important aerosol absorbers.

Optimization of space-constrained micro-perforated absorbers by causality criteria

The problem of space-constrained absorbers in the low frequency range constitutes an area of continuous research. Micro-perforated panels are advantageous because they can be tuned by a proper selection of their constitutive physical parameters including the diameter of the perforations and their separation distance, their thickness and the length of the backing cavity. However, such optimal selection is not straightforward, especially when considering multi-layer partitions. Current optimization algorithms are based on the maximization of the total absorption coefficient averaged over a frequency band, that requires a compromise between the bandwidth and the thickness of the control device. In this work, the problem is analysed on the basis of a causality criterion. This principle is generalized from its formulation in the field of electromagnetism to obtain a relation that correlates the thickness-to-bandwidth performance of a micro-perforated absorber to its total absorption coefficient. Using this relation, an optimization procedure is presented for the sequential selection of the optimal physical parameters for single-layer partitions. An excellent agreement has been found between the optimal values obtained by the causality criterion and those achieved by critical coupling conditions.

Impact of Temperature on Absorption Coefficient of Pure Seawater in the Blue Wavelengths Inferred from Satellite and In Situ Measurements

There has been a long history of interest on how (if) the absorption coefficient of “pure” fresh water (afwλ) and “pure” seawater (aswλ) changes with temperature (T), yet the impact of T reported in the literature differs significantly in the blue domain. Unlike the previous studies based on laboratory measurements, we took an approach based on ~18 years (2002–2020) of MODIS ocean color and temperature measurements in the oligotrophic oceans, along with field measured chlorophyll concentration and phytoplankton absorption coefficient, to examine the relationship between T and the total absorption coefficient (aλ) at 412 and 443 nm. We found that the values of a412 and a443 in the summer are nearly flat (slightly decreasing) for the observed T range of ~19–27 °C. Since there are no detectable changes of chlorophyll during this period, the results suggest that T has a negligible impact on asw412 and asw443 in this T range. As a complement, the impact of salinity on afwλ was also evaluated using three independent determinations of aswλ and afwλ, where good agreements were found from these observations.