Multi-electron Transfer by U(ɪɪ) and Masked U(ɪɪ) Complexes

Complexes of uranium in low oxidation state have shown the ability of activating non-reactive small molecules such as N2. However, the multi-electron transfer required for such activation, remains limited in uranium chemistry. Here, we review our recent research on the use of different strategies to overcome this issue, which has led to the isolation of a diuranium(ɪɪɪ) bridging oxide complex that reacts as a U(ɪɪ) synthon able to effect one-electron transfer per uranium center to N-heterocycles and multi-electron transfer to diphenylacetylene and azobenzene. We also showed that a closely related molecular U(ɪɪ) complex effects the same reactions providing the first unambiguous example of a monouranium four-electron transfer.

Source of All Hair, Wearer of All Socks

I work figuratively in pen, collage, and digital media to portray larger-than-life Black, female characters taking up space in real and imagined worlds. In a series of mural installations, I present a subjective Black woman’s fairytale to process interlocking structures of oppression. Centered in the speculative practice of the Black imaginary that creates spaces of both comfort and confrontation, I tell the story of a Black woman who escapes into an alternate reality made up of only herself, her hair, and the clothes she wears. This text is centered on a chapter of this ongoing narrative, Source of All Hair, Wearer of All Socks, 2022, an installation designed for the Mildred Lane Kemper Art Museum in St. Louis illustrating the power dynamics that emerge in this new reality

Contrasting magnetic behavior of fine particles of some Kondo Lattices

We have investigated the magnetic behavior of ball-milled fine particles of well-known Kondo lattices, CeAu2Si2, CePd2Si2 and CeAl2, by magnetization and heat-capacity studies in order to understand the magnetic behavior when the particle size is reduced. These compounds have been known to order antiferromagnetically in the bulk form near (TN=) 10, 10 and 3.8 K respectively. We find that the features due to magnetic ordering get suppressed to temperatures below 1.8 K in the case of fine particles of ternary alloys, though trivalence of Ce as inferred from the effective moment remains unchanged. In contrast to this, in CeAl2, there appears to be a marginal enhancement of TN, when the particle size is reduced to less than a micron. These results can be consistently understood by proposing that there is relatively more 4f-localization as the particle size is reduced, resulting in weakening of exchange interaction strength

Role of radiosynovectomy in the treatment of rheumatoid arthritis and hemophilic arthropathies

Radiosynovectomy is a novel method of treatment for several acute and chronic inflammatory joint disorders. A small amount of a beta-emitting radionuclide is injected into the affected joint delivering a radiation dose of 70 to 100 Gy to the synovia. The proliferative tissue is destroyed, secretion of fluid and accumulation of inflammation causing cellular compounds stops and the joint surfaces become fibrosed, providing long term symptom relief. The radionuclides are injected in colloidal form so that they remain in the synovium and are not transported by lymphatic vessels causing radiation exposure to other organs. Complete reduction of knee joint swelling has been seen in above 40% and pain relief in 88% of patients. Wrist, elbow, shoulder, ankle and hip joints showed significant improvement in 50-60% and restoration of normal function and long term pain relief has been achieved in about 70% of small finger joints. In hemophilic arthropathies complete cessation of bleeding in about 60% and improved mobility in 75% of patients has been reported

N,N′-Bis[1-(thiophen-2-yl)ethylidene]ethane-1,2-diamine

Mol­ecules of the title compound, C14H16N2S2, have a centre of inversion in the middle of the –CH2–CH2– bond; the (C4H3S)(CH3)C=N–CH2– moiety is almost planar (r.m.s. deviation for non-H atoms 0.027 Å)

Absence of Self-Averaging and Universal Fluctuations in Random Systems Near Critical Points

The distributions P(X) of singular thermodynamic quantities, on an ensemble of d-dimensional quenched random samples of linear size L near a critical point, are analyzed using the renormalization group. For L much larger than the correlation length ξ, we recover strong self-averaging (SA): P(X) approaches a Gaussian with relative squared width RX~(L/ξ)−d. For L≪ξ we show weak SA (RX decays with a small power of L) or no SA [P(X) approaches a non-Gaussian, with universal L-independent relative cumulants], when the randomness is irrelevant or relevant, respectively

Maternal sepsis: a Scottish population-based case–control study

Objective To describe the risk of maternal sepsis associated with obesity and other understudied risk factors such as operative vaginal delivery. Design Population-based, case-control study. Setting North NHS region of Scotland. Population All cases of pregnant, intrapartum and postpartum women with International Classification of Disease-9 codes for sepsis or severe sepsis recorded in the Aberdeen Maternal and Neonatal Databank (AMND) from 1986 to 2009. Four controls per case selected from the AMND were frequency matched on year-of-delivery. Methods Cases and controls were compared; significant variables from univariable regression were adjusted in a multivariable logistic regression model. Main outcome measures Dependent variables were uncomplicated sepsis or severe ('near-miss') sepsis. Independent variables were demographic, medical and clinical delivery characteristics. Unadjusted and adjusted odds ratios (OR) with 95% confidence intervals (95% CI) are reported. Results Controlling for mode of delivery and demographic and clinical factors, obese women had twice the odds of uncomplicated sepsis (OR 2.12; 95% CI 1.14-3.89) compared with women of normal weight. Age <25 years (OR 5.15; 95% CI 2.43-10.90) and operative vaginal delivery (OR 2.20; 95% CI 1.02-4.87) were also significant predictors of sepsis. Known risk factors for maternal sepsis were also significant in this study (OR for uncomplicated and severe sepsis respectively): multiparty (OR 6.29, 12.04), anaemia (OR 3.43, 18.49), labour induction (OR 3.92 severe only), caesarean section (OR 3.23, 13.35), and preterm birth (OR 2.46 uncomplicated only). Conclusions Obesity, operative vaginal delivery and age <25 years are significant risk factors for sepsis and should be considered in clinical obstetric care. © 2012 RCOG

Combined Structure-Based Pharmacophore and 3D-QSAR Studies on Phenylalanine Series Compounds as TPH1 Inhibitors

Tryptophan hydroxylase-1 (TPH1) is a key enzyme in the synthesis of serotonin. As a neurotransmitter, serotonin plays important physiological roles both peripherally and centrally. In this study, a combination of ligand-based and structure-based methods is used to clarify the essential quantitative structure-activity relationship (QSAR) of known TPH1 inhibitors. A multicomplex-based pharmacophore (MCBP) guided method has been suggested to generate a comprehensive pharmacophore of TPH1 kinase based on three crystal structures of TPH1-inhibitor complex. This model has been successfully used to identify the bioactive conformation and align 32 structurally diverse substituted phenylalanine derivatives. The QSAR analyses have been performed on these TPH1 inhibitors based on the MCBP guided alignment. These results may provide important information for further design and virtual screening of novel TPH1 inhibitors

Reduction of the Yb valence in YbAl3 nanoparticles

Measurements of specific heat, dc magnetic susceptibility, and Yb LII and LIII x-ray absorption near-edge structure XANES and extended x-ray absorption fine structure EXAFS on YbAl3 milled alloys are reported. X-ray diffraction patterns are consistent with a reduction in particle size down to 10 nm and an increase in the lattice strain up to 0.4% for 120 h of milling time. A decrease in the mean valence from 2.86 for the unmilled alloy to 2.70 for 120 h milled YbAl3 is obtained from the analysis of XANES spectra. From the analysis of spectra in the EXAFS region, an increase in the mean-square disorder of neighbor distance with milling time is detected in good agreement with the results of x-ray diffraction. Size effects strongly influence the magnetic and thermal properties. The value for the maximum of the magnetic susceptibility decreases around 30% for 120 h milled alloy and an excess specific heat, with a peak around 40 K in the milled samples, is derived. These changes in the physical properties along the milled YbAl3 alloys are associated with the reduction in particle size. Such a reduction leads to the existence of a large number of Yb2+ atoms at the surface with respect to the bulk affecting the overall electronic state