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Estimating the Oblateness of Dark Matter Halos Using Neutral Hydrogen Velocity Dispersion
Get PDFWe derive the oblateness parameter q of the dark matter halo of a sample of gas-rich, face-on disk galaxies. We have assumed that the halos are triaxial in shape but their axes in the disk plane (a and b) are equal, so that q = c/a measures the halo flattening. We have used the H i velocity dispersion, derived from the stacked H i emission lines and the disk surface density, determined from the H i flux distribution, to determine the disk potential and the halo shape at the R 25 and 1.5R 25 radii. We have applied our model to 20 nearby galaxies, of which six are large disk galaxies with M(stellar) \u3e 1010, eight have moderate stellar masses, and six are low-surface-brightness dwarf galaxies. Our most important result is that gas-rich galaxies that have M(gas)/M(baryons) \u3e 0.5 have oblate halos (q \u3c 0.55), whereas stellar-dominated galaxies have a range of q values from 0.21 ± 0.07 in NGC4190 to 1.27 ± 0.61 in NGC5194. Our results also suggest a positive correlation between the stellar mass and the halo oblateness q, which indicates that galaxies with massive stellar disks have a higher probability of having halos that are spherical or slightly prolate, whereas low-mass galaxies have oblate halos (q \u3c 0.55)
Using Multiple Lenses to See an Invisible Group
Get PDFSocial work in Poland and in the United States shares the values of human dignity and self-determination, but there are often value conflicts in terms of how various groups experience social roles and social expectations. This paper explores the use of multiple lenses to understand the past and current conditions for LGBT+ people in Poland. An international, university-level collaboration uses a framework of “invisible groups” to highlight the needs of those who are on the margins of society and whose human and individual rights are suppressed. The article reviews the results of a recently published on-line survey of LGBT+ populations and their views of their experiences in Polish society to illustrate their “invisibility” and the need for advocacy from the international social work community
Understanding the Rhodopsin Worldview Through Atomic Force Microscopy (AFM): Structure, Stability, and Activity Studies
Get PDFRhodopsin is a G protein-coupled receptor (GPCR) present in the rod outer segment (ROS) of photoreceptor cells that initiates the phototransduction cascade required for scotopic vision. Due to the remarkable advancements in technological tools, the chemistry of rhodopsin has begun to unravel especially over the past few decades, but mostly at the ensemble scale. Atomic force microscopy (AFM) is a tool capable of providing critical information from a single-molecule point of view. In this regard, to bolster our understanding of rhodopsin at the nanoscale level, AFM-based imaging, force spectroscopy, and nano-indentation techniques were employed on ROS disc membranes containing rhodopsin, isolated from vertebrate species both in normal and diseased states. These AFM studies on samples from native retinal tissue have provided fundamental insights into the structure and function of rhodopsin under normal and dysfunctional states. We review here the findings from these AFM studies that provide important insights on the supramolecular organization of rhodopsin within the membrane and factors that contribute to this organization, the molecular interactions stabilizing the structure of the receptor and factors that can modify those interactions, and the mechanism underlying constitutive activity in the receptor that can cause disease
Antioxidant Dimethyl Fumarate Temporarily but Not Chronically Improves Intracortical Microelectrode Performance
Get PDFIntracortical microelectrode arrays (MEAs) can be used in a range of applications, from basic neuroscience research to providing an intimate interface with the brain as part of a brain-computer interface (BCI) system aimed at restoring function for people living with neurological disorders or injuries. Unfortunately, MEAs tend to fail prematurely, leading to a loss in functionality for many applications. An important contributing factor in MEA failure is oxidative stress resulting from chronically inflammatory-activated microglia and macrophages releasing reactive oxygen species (ROS) around the implant site. Antioxidants offer a means for mitigating oxidative stress and improving tissue health and MEA performance. Here, we investigate using the clinically available antioxidant dimethyl fumarate (DMF) to reduce the neuroinflammatory response and improve MEA performance in a rat MEA model. Daily treatment of DMF for 16 weeks resulted in a significant improvement in the recording capabilities of MEA devices during the sub-chronic (Weeks 5–11) phase (42% active electrode yield vs. 35% for control). However, these sub-chronic improvements were lost in the chronic implantation phase, as a more exacerbated neuroinflammatory response occurs in DMF-treated animals by 16 weeks post-implantation. Yet, neuroinflammation was indiscriminate between treatment and control groups during the sub-chronic phase. Although worse for chronic use, a temporary improvement (\u3c12 weeks) in MEA performance is meaningful. Providing short-term improvement to MEA devices using DMF can allow for improved use for limited-duration studies. Further efforts should be taken to explore the mechanism behind a worsened neuroinflammatory response at the 16-week time point for DMF-treated animals and assess its usefulness for specific applications
Thermoresponsive Polymers with LCST Transition: Synthesis, Characterization, and their Impact on Biomedical Frontiers
Get PDFAdvances in thermoresponsive materials have significantly impacted many biomedical fields. The unique behavior of reversible phase transition close to the physiological temperatures makes these types of materials a great candidate for a wide variety of biomedical applications including bioimaging, biosensing, injectables, smart surfaces, adhesives, biomanufacturing, and tissue engineering. Thermoresponsive behavior, mainly lower critical solution temperature (LCST) can be easily tuned by shifting the balance between hydrophobicity and hydrophilicity (e.g., by using comonomers or changing end groups) and modifying the molecular weight and architecture of the polymer. Hence, synthetic and characterization tools are critical in tailoring and precisely determining these properties. This review aims to show the full scope of the journey of thermoresponsive polymers from benchtop to potential applications. We especially intend to emphasize the effects of the structural heterogeneity of polymers on thermal transition and highlight the modern characterization techniques used to study thermoresponsive behavior. A better understanding of these structural effects and benchtop tools can help us design and implement more advanced materials for future applications in public health
Temperature Dependence of Crystal Growth Behavior of AlN on Ni–Al using Electromagnetic Levitation and Computer Vision Technique
Get PDFBulk AlN single crystal has a great demand as a substrate material for AlGaN-based optical and electronic devices such as deep ultraviolet light-emitting diodes and high-power transistors. We have previously proposed a novel solution-growth method using Ni–Al solution with an in-situ observation system for solution growth of AlN crystal using electromagnetic levitation. In this paper, to investigate AlN formation behavior on 40 mol%Al–Ni droplets, two precisely synchronized high-speed cameras from the horizontal and vertical directions were installed. AlN formation behavior was evaluated quantitatively using computer vision image processing techniques. Based on the results, we demonstrated the growth of thick AlN film at 2030 K for 1 h. A 3.8-μm-thick c-axis oriented AlN film successfully formed on the droplet, and the film was also oriented in-plane. The + c-direction AlN film grew towards the droplet center from the surface by reacting dissolved nitrogen and Al atoms
Neighbourhood‐Level Social Deprivation and the Risk of Recurrent Heart Failure Hospitalizations in Type 2 Diabetes
Get PDFBackground: The importance of type 2 diabetes mellitus (T2D) in heart failure hospitalizations (HFH) is acknowledged. As information on the prevalence and influence of social deprivation on HFH is limited, we studied this issue in a racially diverse cohort. Methods: Linking data from US Veterans with stable T2D (without prevalent HF) with a zip-code derived population-level social deprivation index (SDI), we grouped them according to increasing SDI as follows: SDI: group I: ≤20; II: 21-40; III: 41-60; IV: 61-80; and V (most deprived) 81-100. Over a 10-year follow-up period, we identified the total (first and recurrent) number of HFH episodes for each patient and calculated the age-adjusted HFH rate [per 1000 patient-years (PY)]. We analysed the incident rate ratio between SDI groups and HFH using adjusted analyses. Results: In 1 012 351 patients with T2D (mean age 67.5 years, 75.7% White), the cumulative incidence of first HFH was 9.4% and 14.2% in SDI groups I and V respectively. The 10-year total HFH rate was 54.8 (95% CI: 54.5, 55.2)/1000 PY. Total HFH increased incrementally from SDI group I [43.3 (95% CI: 42.4, 44.2)/1000 PY] to group V [68.6 (95% CI: 67.8, 69.9)/1000 PY]. Compared with group I, group V patients had a 53% higher relative risk of HFH. The negative association between SDI and HFH was stronger in Black patients (SDI × Race pinteraction \u3c .001). Conclusions: Social deprivation is associated with increased HFH in T2D with a disproportionate influence in Black patients. Strategies to reduce social disparity and equalize racial differences may help to bridge this gap
Clickable Polymer Scaffolds Enable Ce Recovery with Peptide Ligands
Get PDFRare earth elements (REEs) are a vital part of many technologies with particular importance to the renewable energy sector and there is a pressing need for environmentally friendly and sustainable processes to recover and recycle them from waste streams. Functionalized polymer scaffolds are a promising means to recover REEs due to the ability to engineer both transport properties of the porous material and specificity for target ions. In this work, REE adsorbing polymer scaffolds were synthesized by first introducing poly(glycidyl methacrylate) (GMA) brushes onto porous polyvinylidene fluoride (PVDF) surface through activator generated electron transfer atom transfer radical polymerization (AGET ATRP). Azide moieties were then introduced through a ring opening reaction of GMA. Subsequently, REE-binding peptides were conjugated to the polymer surface through copper catalyzed azide alkyne cycloaddition (CuAAC) click chemistry. The presence of GMA, azide, and peptide was confirmed through Fourier transform infrared spectroscopy. Polymer scaffolds functionalized with the REE-binding peptide bound cerium, while polymer scaffolds functionalized with a scrambled control peptide bound significantly less cerium. Importantly, this study shows that the REE binding peptide retains its functionality when bound to a polymer surface. The conjugation strategy employed in this work can be used to introduce peptides onto other polymeric surfaces and tailor surface specificity for a wide variety of ions and small molecules
Small Molecule Inhibitors of 15-PGDH Exploit a Physiologic Induced-Fit Closing System
Get PDF15-prostaglandin dehydrogenase (15-PGDH) is a negative regulator of tissue stem cells that acts via enzymatic activity of oxidizing and degrading PGE2, and related eicosanoids, that support stem cells during tissue repair. Indeed, inhibiting 15-PGDH markedly accelerates tissue repair in multiple organs. Here we have used cryo-electron microscopy to solve the solution structure of native 15-PGDH and of 15-PGDH individually complexed with two distinct chemical inhibitors. These structures identify key 15-PGDH residues that mediate binding to both classes of inhibitors. Moreover, we identify a dynamic 15-PGDH lid domain that closes around the inhibitors, and that is likely fundamental to the physiologic 15-PGDH enzymatic mechanism. We furthermore identify two key residues, F185 and Y217, that act as hinges to regulate lid closing, and which both inhibitors exploit to capture the lid in the closed conformation, thus explaining their sub-nanomolar binding affinities. These findings provide the basis for further development of 15-PGDH targeted drugs as therapeutics for regenerative medicine
You Might Be Causing Harm If … : A Poster Campaign from the McCluskey Center for Violence Prevention Research and Education
Get PDFRates of sexual violence on college campuses have not changed in six decades—cleaer evidence that it is time for new approaches to this pervasive problem. The McCluskey Center for Violence Prevention Research and Education is using a power-conscious framework to shape innovative research and educational efforts aimed at understanding, intervening in, and preventing sexual violence before it happens. The center’s work focuses on those who cause harm or have the potential to cause harm, an intentional effort to shift the narrative around sexual violence on college campuses. This approach informed the “You Might Be Causing Harm If . . .” poster campaign launched by the center in January 2023. The campaign presented eight behaviors identified by student staff as potentially harmful and common among their peers. Posters were linked to blog posts that explained in more detail why the behavior might be harmful and how to avoid it. Among the campaign’s goals: raising awareness and prompting conversations about harmful behavior. The campaign is simple by design and one that could be easily replicated on other college campuses
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