364 research outputs found
Synthesis and Analysis of Copper Beta-Diketonate Complexes
This research addresses the synthesis and characterization of Cu(II) complexes of silicon-based multidentate β-diketonate ligands. The possible products of the synthesis include (where L represents the coordinated ligand) cube Cu12L8, decahedron Cu24L16, and dodecahedron Cu30L20. This study aims to determine the structure of these discrete molecules, which may have applications in drug delivery, fuel storage, and chemical retention. Different techniques were involved in the characterization of Cu(II) complexes: Electrospray Ionization Time of Flight Mass Spectrometry (ESI-TOF MS), Atomic Force Microscopy (AFM) and Analytical Ultracentrifugation (AUC). In ESI-TOF MS, the exact mass of the molecules was attempted to be determined by experimenting if multiply charged ions could occur with these complexes. Although no multiply charged ion peaks were discovered, different experimental conditions yielded different ESI-TOF MS spectra. Additionally in ESI-TOF MS, peaks having large m/z values containing copper atoms were discovered. In AFM studies, heights of multiple copper complexes were measured to see if the discrete molecules of cube (2 nm), decahedron (3.5-4.5 nm), and dodecahedron (5 nm) could be identified. In creating an AFM histogram, the frequency of heights could be used to determine what kind of complexes were being formed and in what percentage. In the studies conducted, there were common occurrences of the samples at or around the heights of the projected structures (e.g. cube, decahedron, and dodecahedron). Additionally, there was a substantial occurrence of measured heights (i.e. 8 nm and 10 nm) that indicated possible aggregation of the discrete molecules. The AUC technique was used to determine whether the samples contained a pure compound or a mixture of discrete molecules, and also to estimate their molecular weight. What was found in the AUC studies of the Cu(II) complexes of silicon-based multidentate β-diketonate ligands were molecular weights similar to the empirical formula of the molecules (i.e. Cu3(MeSi(phac)3)2: 1322.07 g/mol; Cu3(MeSi(phpr)3)2: 1567.80 g/mol) and samples that were polydisperse. No evidence from AUC showed the discovery of compounds which had molecular weights similar to the proposed polyhedra. The numbers are based on assumed densities of 1.138 g/mL
Adult female with symptomatic AVPR2-related nephrogenic syndrome of inappropriate antidiuresis (NSIAD).
UNLABELLED: Activating mutations in AVPR2 are associated with nephrogenic syndrome of inappropriate antidiuresis (NSIAD). NSIAD causes hyponatremia, decreased serum osmolality and clinical symptoms, which may present from birth or in infancy and include hypotonia, irritability, vomiting and/or seizures. Symptoms in later life are often less specific and include malaise, dizziness, confusion, tiredness and headache. NSIAD is a rare X-linked condition, which is associated with a variable phenotype in males, of whom some present in infancy but others do not become symptomatic until adulthood, or occasionally, never. Female carriers may present with episodes of hyponatremia, usually found incidentally. Literature in this field is limited; namely, two clinical reports describing a female proband, both diagnosed in infancy. We describe, for the first time, the case of an adult female proband with NSIAD, who had longstanding associated symptoms of tiredness, headache, temporary memory loss and mood changes as well as hyponatremia and decreased serum osmolality. A water load test demonstrated an inability to dilute urine and gene sequencing confirmed a recurrent activating mutation in AVPR2. The variant was inherited from the proband's mother who had had longstanding episodes of transient asymptomatic hyponatremia. This is the third report of a female proband with NSIAD and is the first female reported who sought medical treatment for chronic symptoms from adulthood. This case acts as a reminder of the importance of considering NSIAD as a diagnosis in females of all ages with unexplained hyponatremia. LEARNING POINTS: Activating mutations in the AVPR2 gene are associated with the rare X-linked condition nephrogenic syndrome of inappropriate antidiuresis.NSIAD is associated with hyponatremia, decreased serum osmolality and inappropriately increased urinary osmolality. Early clinical symptoms in infancy include hypotonia, irritability, vomiting and/or seizures. Symptoms in later life include malaise, dizziness, confusion, tiredness and headache.NSIAD should be considered in female, as well as male, patients who present with unexplained hyponatremia and decreased serum osmolality. Family history may reveal relevant symptoms or biochemical features in other family members. However, family history may not always be informative due to the variable nature of the condition or if the proband has a de novo pathogenic variant.A water load test with measurement of AVP may be informative in distinguishing NSIAD from SIADH. Measurement of co-peptin levels may be considered, in substitution for direct measurement of AVP.Patients with NSIAD should be counseled about appropriate daily fluid volume intake. Potential episodes of fluid overload should be avoided
Fault interactions and reactivation within a normal-fault network at Milne Point, Alaska
A normal-fault network from Milne Point, Alaska, is investigated focusing on characterizing geometry, displacement, strain, and different fault interactions. The network, constrained from three-dimensional seismic reflection data, comprises two generations of faults: Cenozoic north-northeast–trending faults and Jurassic west-northwest–trending faults, which highly compartmentalize Upper Triassic to Lower Cretaceous reservoirs. The west-northwest–trending faults are influenced by a similarly oriented underlying structural grain. This influence is characterized by increases in throw on several faults, strain localization, reorientation of faults and an increase in linkage maturity.Reconstructing fault plane geometries and mapping spatial variations in throw identified key characteristic features in their interactions and reactivation of pre-existing structures. Faults are divided into isolated, abutting, and splaying faults. Isolated faults exhibit a range of displacement profiles depending on the degree of restriction at fault tips. Fault splays accommodate step-like decreases in throw along larger main faults with a throw maximum at the intersection with the main fault. Throw profiles of abutting faults are divided into two groups: early stage abutting faults with throw minima at both the isolated and abutting tips, and developed abutting faults with throw maxima near the abutting tip.Developed abutting faults accumulate throw after initial abutment, locally reactivating and transferring throw onto the pre-existing fault. Two abutting faults can link kinematically by reactivating a segment of the pre-existing fault forming a trailing fault. The motion sense of the trailing fault can be synthetic or antithetic to the reactivated pre-existing fault, producing increases or decreases in the throw of the pre-existing fault, respectivel
The Ursinus Weekly, April 28, 1977
Ursinus news in brief: Mattress team takes second; Chemistry delegates tapped; Cub & Key chooses officers; Classes elect officers; Economics Club elects officers; Library announces new hours; Pre-legal Society elections held • SFARC discusses Weekly • Meal popularity surveyed • GRE revised • Food service names liaison • Comment: After orientation, what then? • Curriculum review urged • Letters to the editor • Musical gobs • Perfection personified • Movie attack: Airport 77 • Band holds concert • Presidential memo • Weekly special: Fidel interested in assassination probe • Songfest \u2777 • Faculty promotions announced • More on food • Sum. Eve. School • Baseball team excites fans • Lacrosse undefeated • Tennis times • Women\u27s tennis • Amateur boxing • Track • Golf • Correction • Mexico triphttps://digitalcommons.ursinus.edu/weekly/1070/thumbnail.jp
Using [Ne V]/[Ne III] to Understand the Nature of Extreme-Ionization Galaxies
Spectroscopic studies of extreme-ionization galaxies (EIGs) are critical to
our understanding of exotic systems throughout cosmic time. These EIGs exhibit
spectral features requiring >54.42 eV photons: the energy needed to fully
ionize helium into He2+ and emit He II recombination lines. They are likely key
contributors to reionization, and they can also probe exotic stellar
populations or accretion onto massive black holes. To facilitate the use of
EIGs as probes of high ionization, we focus on ratios constructed from strong
rest-frame UV/optical emission lines, specifically [O III] 5008, H-beta, [Ne
III] 3870, [O II] 3727,3729, and [Ne V] 3427. These lines probe the relative
intensity at energies of 35.12, 13.62, 40.96, 13.62 eV, and 97.12,
respectively, covering a wider range of ionization than traced by other common
rest-frame UV/optical techniques. We use ratios of these lines ([Ne V]/[Ne III]
= Ne53 and [Ne III]/[O II]), which are closely separated in wavelength, and
mitigates effects of dust attenuation and uncertainties in flux calibration. We
make predictions from photoionization models constructed from Cloudy that use a
broad range of stellar populations and black hole accretion models to explore
the sensitivity of these line ratios to changes in the ionizing spectrum. We
compare our models to observations from the Hubble Space Telescope and James
Webb Space Telescope of galaxies with strong high-ionization emission lines at
z ~ 0, z ~ 2, and z ~ 7. We show that the Ne53 ratio can separate galaxies with
ionization from 'normal' stellar populations from those with AGN and even
'exotic' Population III models. We introduce new selection methods to identify
galaxies with photoionization driven by Population III stars or
intermediate-mass black hole accretion disks that could be identified in
upcoming high-redshift spectroscopic surveys.Comment: 16 pages, 5 figures, 1 table. Accepted in Ap
Dietary nitrate reduces muscle metabolic perturbation and improves exercise tolerance in hypoxia
The definitive version is available at www3.interscience.wiley.comExercise in hypoxia is associated with reduced muscle oxidative function and impaired exercise tolerance. We hypothesised that dietary nitrate supplementation (which increases plasma [nitrite] and thus NO bioavailability) would ameliorate the adverse effects of hypoxia on muscle metabolism and oxidative function. In a double-blind, randomised crossover study, nine healthy subjects completed knee-extension exercise to the limit of tolerance (T(lim)), once in normoxia (20.9% O(2); CON) and twice in hypoxia (14.5% O(2)). During 24 h prior to the hypoxia trials, subjects consumed 0.75 L of nitrate-rich beetroot juice (9.3 mmol nitrate; H-BR) or 0.75 L of nitrate-depleted beetroot juice as a placebo (0.006 mmol nitrate; H-PL). Muscle metabolism was assessed using calibrated (31)P-MRS. Plasma [nitrite] was elevated (P < 0.01) following BR (194 ± 51 nm) compared to PL (129 ± 23 nm) and CON (142 ± 37 nM). T(lim) was reduced in H-PL compared to CON (393 ± 169 vs. 471 ± 200 s; P < 0.05) but was not different between CON and H-BR (477 ± 200 s). The muscle [PCr], [P(i)] and pH changed at a faster rate in H-PL compared to CON and H-BR. The [PCr] recovery time constant was greater (P < 0.01) in H-PL (29 ± 5 s) compared to CON (23 ± 5 s) and H-BR (24 ± 5 s). Nitrate supplementation reduced muscle metabolic perturbation during exercise in hypoxia and restored exercise tolerance and oxidative function to values observed in normoxia. The results suggest that augmenting the nitrate-nitrite-NO pathway may have important therapeutic applications for improving muscle energetics and functional capacity in hypoxia
Compendium of Single Event Effects, Total Ionizing Dose, and Displacement Damage for Candidate Spacecraft Electronics for NASA
We present results and analysis investigating the effects of radiation on a variety of candidate spacecraft electronics to proton and heavy ion-induced single-event effects (SEE), proton-induced displacement damage (DD), and total ionizing dose (TID). This paper is a summary of test results
CEERS Spectroscopic Confirmation of NIRCam-Selected z > 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of their Properties
We present JWST NIRSpec spectroscopy for 11 galaxy candidates with
photometric redshifts of and newly
identified in NIRCam images in the Cosmic Evolution Early Release Science
(CEERS) Survey. We confirm emission line redshifts for 7 galaxies at
using spectra at m either with the NIRSpec prism or
its three medium resolution gratings. For photometric candidates, we
achieve a high confirmation rate of 90\%, which validates the classical
dropout selection from NIRCam photometry. No robust emission lines are
identified in three galaxy candidates at , where the strong [OIII] and
H lines would be redshifted beyond the wavelength range observed by
NIRSpec, and the Lyman- continuum break is not detected with the
current sensitivity. Compared with HST-selected bright galaxies
() that are similarly spectroscopically confirmed at
, these NIRCam-selected galaxies are characterized by lower star
formation rates (SFR~yr) and lower stellar masses
(), but with higher [OIII]+H equivalent widths
(1100), and elevated production efficiency of ionizing photons
() induced by young stellar
populations (~Myrs) accounting for of the galaxy mass,
highlighting the key contribution of faint galaxies to cosmic reionization.
Taking advantage of the homogeneous selection and sensitivity, we also
investigate metallicity and ISM conditions with empirical calibrations using
the [OIII]/H ratio. We find that galaxies at have higher SFRs
and lower metallicities than galaxies at similar stellar masses at ,
which is generally consistent with the current galaxy formation and evolution
models.Comment: 21 pages, 11 figures, 2 tables. Submitted to ApJL Focus Issu
Spectroscopic verification of very luminous galaxy candidates in the early universe
During the first 500 million years of cosmic history, the first stars and
galaxies formed and seeded the cosmos with heavy elements. These early galaxies
illuminated the transition from the cosmic "dark ages" to the reionization of
the intergalactic medium. This transitional period has been largely
inaccessible to direct observation until the recent commissioning of JWST,
which has extended our observational reach into that epoch. Excitingly, the
first JWST science observations uncovered a surprisingly high abundance of
early star-forming galaxies. However, the distances (redshifts) of these
galaxies were, by necessity, estimated from multi-band photometry. Photometric
redshifts, while generally robust, can suffer from uncertainties and/or
degeneracies. Spectroscopic measurements of the precise redshifts are required
to validate these sources and to reliably quantify their space densities,
stellar masses, and star formation rates, which provide powerful constraints on
galaxy formation models and cosmology. Here we present the results of JWST
follow-up spectroscopy of a small sample of galaxies suspected to be amongst
the most distant yet observed. We confirm redshifts z > 10 for two galaxies,
including one of the first bright JWST-discovered candidates with z = 11.4, and
show that another galaxy with suggested z ~ 16 instead has z = 4.9, with strong
emission lines that mimic the expected colors of more distant objects. These
results reinforce the evidence for the rapid production of luminous galaxies in
the very young Universe, while also highlighting the necessity of spectroscopic
verification for remarkable candidates.Comment: Submitted to Natur
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Individual common variants exert weak effects on the risk for autism spectrum disorders.
While it is apparent that rare variation can play an important role in the genetic architecture of autism spectrum disorders (ASDs), the contribution of common variation to the risk of developing ASD is less clear. To produce a more comprehensive picture, we report Stage 2 of the Autism Genome Project genome-wide association study, adding 1301 ASD families and bringing the total to 2705 families analysed (Stages 1 and 2). In addition to evaluating the association of individual single nucleotide polymorphisms (SNPs), we also sought evidence that common variants, en masse, might affect the risk. Despite genotyping over a million SNPs covering the genome, no single SNP shows significant association with ASD or selected phenotypes at a genome-wide level. The SNP that achieves the smallest P-value from secondary analyses is rs1718101. It falls in CNTNAP2, a gene previously implicated in susceptibility for ASD. This SNP also shows modest association with age of word/phrase acquisition in ASD subjects, of interest because features of language development are also associated with other variation in CNTNAP2. In contrast, allele scores derived from the transmission of common alleles to Stage 1 cases significantly predict case status in the independent Stage 2 sample. Despite being significant, the variance explained by these allele scores was small (Vm< 1%). Based on results from individual SNPs and their en masse effect on risk, as inferred from the allele score results, it is reasonable to conclude that common variants affect the risk for ASD but their individual effects are modest
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