| 1. |
|
|
| 2. |
- Hsiao, Tiger Yu-Yang, et al.
(author)
-
JWST Reveals a Possible z similar to 11 Galaxy Merger in Triply Lensed MACS0647-JD
- 2023
-
In: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8205 .- 2041-8213. ; 949:2
-
Journal article (peer-reviewed)abstract
- MACS0647-JD is a triply lensed z similar to 11 galaxy originally discovered with the Hubble Space Telescope. The three lensed images are magnified by factors of similar to 8, 5, and 2 to AB mag 25.1, 25.6, and 26.6 at 3.5 mu m. The brightest is over a magnitude brighter than other galaxies recently discovered at similar redshifts z > 10 with JWST. Here, we report new JWST imaging that clearly resolves MACS0647-JD as having two components that are either merging galaxies or stellar complexes within a single galaxy. The brighter larger component "A" is intrinsically very blue (ss similar to-2.6 +/- 0.1), likely due to very recent star formation and no dust, and is spatially extended with an effective radius similar to 70 +/- 24 pc. The smaller component "B" (r similar to 20-+ 58 pc) appears redder (ss similar to-2 +/- 0.2), likely because it is older (100-200 Myr) with mild dust extinction (AV similar to 0.1 mag). With an estimated stellar mass ratio of roughly 2:1 and physical projected separation similar to 400 pc, we may be witnessing a galaxy merger 430 million years after the Big Bang. We identify galaxies with similar colors in a high-redshift simulation, finding their star formation histories to be dissimilar, which is also suggested by the spectral energy distribution fitting, suggesting they formed further apart. We also identify a candidate companion galaxy "C" similar to 3 kpc away, likely destined to merge with A and B. Upcoming JWST Near Infrared Spectrograph observations planned for 2023 January will deliver spectroscopic redshifts and more physical properties for these tiny magnified distant galaxies observed in the early universe.
|
|
| 3. |
- Katsiotis, Christos S.
(author)
-
Additive Manufacturing and Mesoporous Materials for Pharmaceutical Applications
- 2024
-
Doctoral thesis (other academic/artistic)abstract
- Additive Manufacturing (AM), over the past decade, has evolved into a versatile technology with significant applications in pharmaceutical research. This technology enables the production of drug formulations tailored to individual patients, offering customization in both dosage and dissolution profiles. While challenges in mass production persist, 3D printing, particularly through techniques like Fused Deposition Modeling (FDM) and Semi Solid Extrusion (SSE), proves ideal for crafting smaller batches of personalized dosage forms.A prevalent issue in drug development revolves around poor water solubility, impacting bioavailability upon oral administration. To combat this, the integration of mesoporous materials emerges as a promising strategy to enhance the dissolution of poorly water-soluble drugs. Here, the applicability of mesoporous materials is explored, as well as their incorporation with various AM techniques. Overall, the thesis dives into the investigation of combinatorial formulations, incorporating at least one 3D printed component to address specific requirements in drug delivery. By combining FDM with Selective Laser Sintering (SLS), a hybrid two-compartmental formulation is developed. The durable FDM-printed shell regulates buffer medium access to the contained SLS-produced inserts loaded with the drug. Varying printing parameters and insert combinations within the shell showcase the adjustability and flexibility of this hybrid approach.Tablets with different infill percentages, containing drug-loaded mesoporous materials, are developed. Poorly water-soluble drugs are successfully amorphized within mesoporous material pores, formulated into filaments through Hot Melt Extrusion (HME), and printed via FDM. These tablets exhibit improved dissolution compared to the crystalline drug, with the dissolution behavior regulated also by the infill percentage.The study explores the impact of drug-loaded mesoporous materials on HME-produced filament properties, studying their effect on maximum tensile strength and Young’s modulus. The relationship between these properties and filament printability is investigated. Additionally, a protective effect of mesoporous materials on drugs from thermal degradation is revealed.For Semi Solid Extrusion (SSE) manufactured formulations, a paste is developed, comprising mesoporous material loaded with a poorly water-soluble drug and an excipient. This paste demonstrates favorable rheological properties and easy extrudability via a syringe. The formulation proves versatile for printing dosage forms for both oral and rectal administration, with the printed tablet and suppository exhibiting effective drug release.In conclusion, this work presents valuable strategies for developing patient-tailored dosage forms, addressing specific pharmaceutical challenges like poor solubility. The integration of mesoporous materials and various 3D printing techniques showcases a promising direction for personalized medicine in the pharmaceutical field.
|
|
| 4. |
- Viñuela, Ana, et al.
(author)
-
Genetic variant effects on gene expression in human pancreatic islets and their implications for T2D
- 2020
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1, s. 4912-4912
-
Journal article (peer-reviewed)abstract
- Most signals detected by genome-wide association studies map to non-coding sequence and their tissue-specific effects influence transcriptional regulation. However, key tissues and cell-types required for functional inference are absent from large-scale resources. Here we explore the relationship between genetic variants influencing predisposition to type 2 diabetes (T2D) and related glycemic traits, and human pancreatic islet transcription using data from 420 donors. We find: (a) 7741 cis-eQTLs in islets with a replication rate across 44 GTEx tissues between 40% and 73%; (b) marked overlap between islet cis-eQTL signals and active regulatory sequences in islets, with reduced eQTL effect size observed in the stretch enhancers most strongly implicated in GWAS signal location; (c) enrichment of islet cis-eQTL signals with T2D risk variants identified in genome-wide association studies; and (d) colocalization between 47 islet cis-eQTLs and variants influencing T2D or glycemic traits, including DGKB and TCF7L2. Our findings illustrate the advantages of performing functional and regulatory studies in disease relevant tissues.
|
|
| 5. |
- Welch, Brian, et al.
(author)
-
JWST Imaging of Earendel, the Extremely Magnified Star at Redshift z=6.2
- 2022
-
In: Astrophysical Journal Letters. - : Institute of Physics (IOP). - 2041-8205 .- 2041-8213. ; 940
-
Journal article (peer-reviewed)abstract
- The gravitationally lensed star WHL 0137-LS, nicknamed Earendel, was identified with a photometric redshift z (phot) = 6.2 +/- 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8-5.0 mu m. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to mu > 4000 and restricting the source plane radius further to r < 0.02 pc, or similar to 4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T (eff) similar to 13,000-16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from log(L)=5.8 L-theta, which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.
|
|
| 6. |
- Windhorst, Rogier A., et al.
(author)
-
JWST PEARLS. Prime extragalactic areas for reionization and lensing science : project overview and first results
- 2023
-
In: Astronomical Journal. - : Institute of Physics (IOP). - 0004-6256 .- 1538-3881. ; 165:1
-
Journal article (peer-reviewed)abstract
- We give an overview and describe the rationale, methods, and first results from NIRCam images of the JWST “Prime Extragalactic Areas for Reionization and Lensing Science” (PEARLS) project. PEARLS uses up to eight NIRCam filters to survey several prime extragalactic survey areas: two fields at the North Ecliptic Pole (NEP); seven gravitationally lensing clusters; two high redshift protoclusters; and the iconic backlit VV 191 galaxy system to map its dust attenuation. PEARLS also includes NIRISS spectra for one of the NEP fields and NIRSpec spectra of two high-redshift quasars. The main goal of PEARLS is to study the epoch of galaxy assembly, active galactic nucleus (AGN) growth, and First Light. Five fields—the JWST NEP Time-Domain Field (TDF), IRAC Dark Field, and three lensing clusters—will be observed in up to four epochs over a year. The cadence and sensitivity of the imaging data are ideally suited to find faint variable objects such as weak AGN, high-redshift supernovae, and cluster caustic transits. Both NEP fields have sightlines through our Galaxy, providing significant numbers of very faint brown dwarfs whose proper motions can be studied. Observations from the first spoke in the NEP TDF are public. This paper presents our first PEARLS observations, their NIRCam data reduction and analysis, our first object catalogs, the 0.9–4.5 μm galaxy counts and Integrated Galaxy Light. We assess the JWST sky brightness in 13 NIRCam filters, yielding our first constraints to diffuse light at 0.9–4.5 μm. PEARLS is designed to be of lasting benefit to the community.
|
|
