Optically pure heterobimetallic helicates from self-assembly and click strategies

Single diastereomer, diamagnetic, octahedral Fe(II) tris chelate complexes are synthesised that contain three pendant pyridine proligands pre-organised for coordination to a second metal. They bind Cu(I) and Ag(I) with coordination geometry depending on the identity of the metal and the detail of the ligand structure, but for example homohelical (ΔFe,ΔCu) configured systems with unusual trigonal planar Cu cations are formed exclusively in solution as shown by VT-NMR and supported by DFT calculations. Similar heterobimetallic tris(triazole) complexes are synthesised via clean CuAAC reactions at a tris(alkynyl) complex, although here the configurations of the two metals differ (ΔFe,ΛCu), leading to the first optically pure heterohelicates. A second series of Fe complexes perform less well in either strategy as a result of lack of preorganisation

Paleolimnological Assessment of Six Lakes on the Kissimmee Chain, with Implications for Restoration of the Kissimmee-Okeechobee-Everglades system, Florida, USA

Whitmore TJ, Riedinger-Whitmore MA, Reed ZE, Curtis JH, Yang H, Evans DE, Cropper NR, Alvarado KS, Lauterman FM, Scott A, Leonard CR, Franklin DL. 2020. Paleolimnological assessment of six lakes on the Kissimmee Chain, with implications for restoration of the Kissimmee–Okeechobee–Everglades system, Florida, USA. Lake Reserv Manage. 36:218–242. The Kissimmee Basin in south central Florida contains a large, freshwater network that includes the Kissimmee River and nearly 2 dozen lakes that are headwaters of the Florida Everglades. Management of these lakes is an important part of Everglades restoration. We report a paleolimnological investigation of 6 lakes in the Upper Kissimmee Basin. Engineering activities connected the lakes and permanently altered hydrology in the 19th and 20th centuries. The lakes were naturally meso-eutrophic, but changes in lake levels and nutrient loading contributed to different degrees of eutrophication. Cyanobacteria were present historically at low levels in Lakes East Tohopekaliga, Cypress, and Tohopekaliga, but increased during the 20th century. Lake Jackson lacked cyanobacteria until recently, but Lakes Kissimmee and Marian have had high levels of cyanobacteria since predisturbance times. Profound changes in the lakes occurred after engineering activities eliminated natural large fluctuations in water levels that periodically dried large portions of the basins. Salt-tolerant biological indicators previously alternated with freshwater organisms. Large water-level fluctuations moderated aquatic-plant standing crops and reduced organic matter accumulation. Lakes Kissimmee and Marian showed greatest evidence of former associated wetlands, but lacked large variations in water levels. We recommend disconnecting these lakes from each other and from the Kissimmee River to reestablish large, natural fluctuations in water levels that were part of healthy ecosystem function. Former wetlands should be restored to slow the downstream cascade of nutrients to Lake Okeechobee and the Everglades. This study demonstrates that paleolimnology is useful for assessing hydrological changes that potentially affect lake restoration efforts

Resonant capture, counter-rotating disks, and polar rings

We suggest that polar rings and/or counter-rotating disks in flattened galaxies can be formed from stars captured at the Binney resonance, where the rate of precession of the angular momentum vector of a disk star equals the pattern speed of a triaxial halo. If the halo pattern speed is initially retrograde and slowly decays to zero, stars can be trapped as the Binney resonance sweeps past them, and levitated into polar orbits. If the halo pattern speed is initially retrograde and slowly changes to prograde, trapped stars can evolve from prograde to retrograde disk orbits. The stellar components of polar rings formed by this process should consist of two equal, counter-rotating star streams.Comment: 10 pages, 6 figures, Latex. Submitted to MNRA

HI Observations of Interacting Galaxy Pair NGC 4038/9

We present the results of new radio interferometer HI line observations for the merging galaxy pair NGC 4038/9 (`The Antennae'), obtained using the Australia Telescope Compact Array. The results improve substantially on those of van der Hulst (1979) and show in detail the two merging galactic disks and the two tidal tails produced by their interaction. The small edge-on spiral dwarf galaxy ESO 572-G045 is also seen near the tip of the southern tail, but distinct from it. It shows no signs of tidal interaction. The northern tidal tail of the Antennae shows no HI connection to the disks and has an extension towards the west. The southern tidal tail is continuous, with a prominent HI concentration at its tip, roughly at the location of the tidal dwarf galaxy observed optically by Mirabel, Dottori & Lutz (1992). Clear velocity structure is seen along the tidal tails and in the galactic disks. Radio continuum images at 20-cm and 13-cm are also presented, showing the disks in detail.Comment: 22 pages, 8 figures, Accepted by MNRAS (April 2001

Portfolio selection models: A review and new directions

Modern Portfolio Theory (MPT) is based upon the classical Markowitz model which uses variance as a risk measure. A generalization of this approach leads to mean-risk models, in which a return distribution is characterized by the expected value of return (desired to be large) and a risk value (desired to be kept small). Portfolio choice is made by solving an optimization problem, in which the portfolio risk is minimized and a desired level of expected return is specified as a constraint. The need to penalize different undesirable aspects of the return distribution led to the proposal of alternative risk measures, notably those penalizing only the downside part (adverse) and not the upside (potential). The downside risk considerations constitute the basis of the Post Modern Portfolio Theory (PMPT). Examples of such risk measures are lower partial moments, Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR). We revisit these risk measures and the resulting mean-risk models. We discuss alternative models for portfolio selection, their choice criteria and the evolution of MPT to PMPT which incorporates: utility maximization and stochastic dominance

Transcriptomic analysis across nasal, temporal, and macular regions of human neural retina and RPE/choroid by RNA-Seq

AbstractProper spatial differentiation of retinal cell types is necessary for normal human vision. Many retinal diseases, such as Best disease and male germ cell associated kinase (MAK)-associated retinitis pigmentosa, preferentially affect distinct topographic regions of the retina. While much is known about the distribution of cell types in the retina, the distribution of molecular components across the posterior pole of the eye has not been well-studied. To investigate regional difference in molecular composition of ocular tissues, we assessed differential gene expression across the temporal, macular, and nasal retina and retinal pigment epithelium (RPE)/choroid of human eyes using RNA-Seq. RNA from temporal, macular, and nasal retina and RPE/choroid from four human donor eyes was extracted, poly-A selected, fragmented, and sequenced as 100 bp read pairs. Digital read files were mapped to the human genome and analyzed for differential expression using the Tuxedo software suite. Retina and RPE/choroid samples were clearly distinguishable at the transcriptome level. Numerous transcription factors were differentially expressed between regions of the retina and RPE/choroid. Photoreceptor-specific genes were enriched in the peripheral samples, while ganglion cell and amacrine cell genes were enriched in the macula. Within the RPE/choroid, RPE-specific genes were upregulated at the periphery while endothelium associated genes were upregulated in the macula. Consistent with previous studies, BEST1 expression was lower in macular than extramacular regions. The MAK gene was expressed at lower levels in macula than in extramacular regions, but did not exhibit a significant difference between nasal and temporal retina. The regional molecular distinction is greatest between macula and periphery and decreases between different peripheral regions within a tissue. Datasets such as these can be used to prioritize candidate genes for possible involvement in retinal diseases with regional phenotypes

A Mutation in LTBP2 Causes Congenital Glaucoma in Domestic Cats (Felis catus)

The glaucomas are a group of diseases characterized by optic nerve damage that together represent a leading cause of blindness in the human population and in domestic animals. Here we report a mutation in LTBP2 that causes primary congenital glaucoma (PCG) in domestic cats. We identified a spontaneous form of PCG in cats and established a breeding colony segregating for PCG consistent with fully penetrant, autosomal recessive inheritance of the trait. Elevated intraocular pressure, globe enlargement and elongated ciliary processes were consistently observed in all affected cats by 8 weeks of age. Varying degrees of optic nerve damage resulted by 6 months of age. Although subtle lens zonular instability was a common feature in this cohort, pronounced ectopia lentis was identified in less than 10% of cats examined. Thus, glaucoma in this pedigree is attributed to histologically confirmed arrest in the early post-natal development of the aqueous humor outflow pathways in the anterior segment of the eyes of affected animals. Using a candidate gene approach, significant linkage was established on cat chromosome B3 (LOD 18.38, θ = 0.00) using tightly linked short tandem repeat (STR) loci to the candidate gene, LTBP2. A 4 base-pair insertion was identified in exon 8 of LTBP2 in affected individuals that generates a frame shift that completely alters the downstream open reading frame and eliminates functional domains. Thus, we describe the first spontaneous and highly penetrant non-rodent model of PCG identifying a valuable animal model for primary glaucoma that closely resembles the human disease, providing valuable insights into mechanisms underlying the disease and a valuable animal model for testing therapies

Effect of Neuromuscular Electrical Muscle Stimulation on Energy Expenditure in Healthy Adults

Weight loss/weight control is a major concern in prevention of cardiovascular disease and the realm of health promotion. The primary aim of this study was to investigate the effect of neuromuscular electrical stimulation (NMES) at different intensities on energy expenditure (oxygen and calories) in healthy adults. The secondary aim was to develop a generalized linear regression (GEE) model to predict the increase of energy expenditure facilitated by NMES and identify factors (NMES stimulation intensity level, age, body mass index, weight, body fat percentage, waist/hip ratio, and gender) associated with this NMES-induced increase of energy expenditure. Forty sedentary healthy adults (18 males and 22 females) participated. NMES was given at the following stimulation intensities for 10 minutes each: sensory level (E1), motor threshold (E2), and maximal intensity comfortably tolerated (E3). Cardiopulmonary gas exchange was evaluated during rest, NMES, and recovery stage. The results revealed that NMES at E2 and E3 significantly increased energy expenditure and the energy expenditure at recovery stage was still significantly higher than baseline. The GEE model demonstrated that a linear dose-response relationship existed between the stimulation intensity and the increase of energy expenditure. No subject’s demographic or anthropometric characteristics tested were significantly associated with the increase of energy expenditure. This study suggested NMES may be used to serve as an additional intervention for weight loss programs. Future studies to develop electrical stimulators or stimulation electrodes to maximize the comfort of NMES are recommended