An update on the ophthalmic features in hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary haemorrhagic telangiectasia (HHT) or Osler-Rendu-Weber syndrome is a rare autosomal dominant disease, characterised by systemic angiodysplasia. Dysfunction of the signalling pathway of β transforming growth factor is the main cause of HHT principally owing to mutations of the genes encoding for endoglin (ENG) and activin A receptor type II-like 1 (ACVRL1). Clinical manifestations can range from mucocutaneous telangiectasia to organ arterio-venous malformations and recurrent epistaxis. The early clinical manifestations may sometimes be subtle, and diagnosis may be delayed. The main ophthalmic manifestations historically reported in HHT are haemorrhagic epiphora, and conjunctival telangiectasia present in 45–65% of cases, however, imaging with wide-field fluorescein angiography has recently shown peripheral retinal telangiectasia in 83% of patients. Optimal management of HHT requires both understanding of the clinical presentations and detection of early signs of disease. Advances in imaging methods in ophthalmology such as wide-field fluorescein angiography, spectral domain optical coherence tomography, and near infrared reflectance promise further insight into the ophthalmic signs of HHT towards improved diagnosis and early management of possible severe complications.

Wavelength-Dependent Seeing Systematically Changes the Normalized Slope of Telescopic Reflectance Spectra of Mercury

Telescopic observations of Mercury consistently report systematic variations of the normalized spectral slope of visible-to-near-infrared reflectance spectra. This effect was previously assumed to be a photometric property of the regolith, but it is not yet fully understood. After the MESSENGER mission, detailed global spectral maps of Mercury are available that better constrain Mercury’s photometry. So far, wavelength-dependent seeing has not been considered in the context of telescopic observations of Mercury. This study investigates the effect of wavelength-dependent seeing on systematic variations of Mercury’s normalized spectral reflectance slope. Therefore, we simulate the disk of Mercury for an idealized scenario, as seen by four different telescopic campaigns using the Hapke and the Kaasalainen–Shkuratov photometric model, the MDIS global mosaic, and a simple wavelength-dependent seeing model. The simulation results are compared with the observations of previous telescopic studies. We find that wavelength-dependent seeing affects the normalized spectral slope in several ways. The normalized slopes are enhanced near the limb, decrease toward the rim of the seeing disk, and even become negative. The decrease of the normalized spectral slope is consistent with previous observations. However, previous studies have associated the spectral slope variations with photometric effects that correlate with the emission angle. Our study suggests that wavelength-dependent seeing may cause these systematic variations. The combined reflectance and seeing model can also account for slope variations between different measurement campaigns. We report no qualitative differences between results based on the Hapke model or the Kaasalainen–Shkuratov model.

The Relative Performance of a Benchtop Scanning Monochromator and Handheld Fourier Transform Near-Infrared Reflectance Spectrometer in Predicting Forage Nutritive Value

Advanced manufacturing techniques have enabled low-cost, on-chip spectrometers. Little research exists, however, on their performance relative to the state of technology systems. The present study compares the utility of a benchtop FOSS NIRSystems 6500 (FOSS) to a handheld NeoSpectra-Scanner (NEO) to develop models that predict the composition of dried and ground grass, and alfalfa forages. Mixed-species prediction models were developed for several forage constituents, and performance was assessed using an independent dataset. Prediction models developed with spectra from the FOSS instrument had a standard error of prediction (SEP, % DM) of 1.4, 1.8, 3.3, 1.0, 0.42, and 1.3, for neutral detergent fiber (NDF), true in vitro digestibility (IVTD), neutral detergent fiber digestibility (NDFD), acid detergent fiber (ADF), acid detergent lignin (ADL), and crude protein (CP), respectively. The R2P for these models ranged from 0.90 to 0.97. Models developed with the NEO resulted in an average increase in SEP of 0.14 and an average decrease in R2P of 0.002.

The use of near-infrared reflectance spectroscopy (NIRS) to predict dairy fibre feeds in vitro digestibility

Information on dairy fibre feed digestibility is important in ration formulation to better predict dairy cattle performance. However, its measurement takes time. Near-infrared reflectance spectroscopy (NIRS) is a rapid, precise, and cost-effective method to predict nutrient value, such as chemical content and digestibility of feedstuffs. This study aims to develop a database for an in vitro digestibility prediction model using NIRS, including dry matter digestibility (DMD), neutral and acid detergent fibre digestibility (NDFD and ADFD), and hemicellulose digestibility (HSD). Eighty dietary fibre feeds consisting of Napier grass, natural grass, rice straw, corn stover, and corn-husk were collected from four dairy farming areas in West Java (Cibungbulang District of Bogor Regency, Parung Kuda District of Sukabumi Regency, Pangalengan District of Bandung Regency, and Lembang District of West Bandung Regency). The spectrum for each sample was collected thrice using NIRSflex 500, which was automatically separated by 2/3 for calibration and 1/3 for validation. External validation was conducted by measuring 20 independent samples. Calibration and validation models were carried out by NIRCal V5.6 using the partial least squares (PLS) regression. The results showed that all parameters produce r2 > 0.5 except for ADFD. Relative prediction deviation (RPD) > 1.5 was only found in hemicellulose digestibility prediction. RPL (SEP/SEL) <1.0 were found in DMD and hemicellulose digestibility. It is concluded that hemicellulose digestibility can be predicted using NIRS accurately while other parameters need improvement.

Near-Infrared Reflectance Spectroscopy (NIRS) detection to differentiate morning and afternoon milk based on nutrient contents and fatty acid profiles

Milking time is one of the factors that affect milk quality. The objective of this study was to differentiate morning milk from afternoon based on milk fatty acid profile and create a prediction model using Near-Infrared Reflectance Spectroscopy (NIRS). This study used explorative research and post-observation analysis. Milk sampling was collected from three different dairy farm locations in West Java Provinces (Pangalengan district of Bandung Regency, Cibungbulang District of Bogor Regency, and Tanah Sareal District of Bogor Municipality). Milk quality observed in this study included milk fat, protein, lactose, solid non-fat (SNF), and fatty acid compositions. Milk fat, protein, lactose, and SNF were analyzed using Lactoscan. Fatty acid compositions were identified using gas chromatography (GC). Sample spectrums were collected using NIRSflex 500. The difference between morning and afternoon milking was tested using a t-test carried out by SPSS ver. 25. Qualitative calibration of milk quality was conducted using NIRSCal v5.6 by applying the cluster (CLU) method. The results from lactoscan and GC showed that milk fat, caprylic acid, and myristoleic acid, and total SFA were significantly different (Sig. (2-tailed) < 0.05) in morning and afternoon milk. However, NIRS failed to generate a sophisticated model for the milk quality differentiation, which shows a low Q-value (0.0011231). The quantitative analysis accurately produced milk fat and total SFA predictions but failed to accurately predict caprylic acid and myristoleic acid. This study concluded that morning milk could be differentiated from afternoon milk based on milk fat, caprylic acid, myristoleic acid, and total SFA content. The NIRS technology can differentiate between morning and afternoon milk based on quantitative calibration of total fat and SFA.

Preliminary analysis of the Hayabusa2 samples returned from C-type asteroid Ryugu

C-type asteroids1 are considered to be primitive small Solar System bodies enriched in water and organics, providing clues to the origin and evolution of the Solar System and the building blocks of life. C-type asteroid 162173 Ryugu has been characterized by remote sensing2–7 and on-asteroid measurements8,9 with Hayabusa2 (ref. 10). However, the ground truth provided by laboratory analysis of returned samples is invaluable to determine the fine properties of asteroids and other planetary bodies. We report preliminary results of analyses on returned samples from Ryugu of the particle size distribution, density and porosity, spectral properties and textural properties, and the results of a search for Ca–Al-rich inclusions (CAIs) and chondrules. The bulk sample mainly consists of rugged and smooth particles of millimetre to submillimetre size, confirming that the physical and chemical properties were not altered during the return from the asteroid. The power index of its size distribution is shallower than that of the surface boulder observed on Ryugu11, indicating differences in the returned Ryugu samples. The average of the estimated bulk densities of Ryugu sample particles is 1,282 ± 231 kg m−3, which is lower than that of meteorites12, suggesting a high microporosity down to the millimetre scale, extending centimetre-scale estimates from thermal measurements5,9. The extremely dark optical to near-infrared reflectance and spectral profile with weak absorptions at 2.7 and 3.4 μm imply a carbonaceous composition with indigenous aqueous alteration, matching the global average of Ryugu3,4 and confirming that the sample is representative of the asteroid. Together with the absence of submillimetre CAIs and chondrules, these features indicate that Ryugu is most similar to CI chondrites but has lower albedo, higher porosity and more fragile characteristics.