Computational and Experimental Investigations of Osmium-Rich Borides Hf2MOs5B2 (M = Mn, Fe, Co): From Spin Glass to Room-Temperature Magnetic Behaviors

The metal borides, Hf2MOs5B2 (M = Mn, Fe, Co), which are the first Os-rich quaternary variants of the prolific Ti3Co5B2 structure type, were investigated computationally and experimentally. In their crystal structures, osmium builds a network of prisms, in which the other elements are located. The magnetic M elements are found in face-connected Os8 square prisms leading to M-chains with intra- and interchain distances of about 3.0 and 6.5 Å, respectively. Density functional theory (DFT) showed that magnetic ordering is hugely favored for M = Mn and Fe but only slightly favored for M = Co. Experimental investigations then confirmed and extended the DFT predictions as a metamagnetic behavior was found for the M = Mn and Fe phases, whereby the antiferromagnetic interactions (TN = 19 and 90 K) found at low magnetic fields change to ferromagnetic at higher fields. A very broad transition (TN = 45 K) is found for M = Co, suggesting spin-glass behavior for this phase. For M = Fe, a hard-magnet hysteresis at 5 K is found with a 40 kA/m coercivity, and even at room temperature, a significant hysteresis is found. This study paves the way for the discovery of Os-based magnets in this structure type and other intermetallics.

Hetero-trimetallic complexes comprising bridging boryl and borylene ligands: an experimental and theoretical study

In an effort to explore the coordination chemistry of the coordinative sulfur centers in arachno-ruthenaborane [(Cp*Ru)2(B3H8)(CS2H)] (arachno-1), we have thermolyzed arachno-1 with group-6 metal carbonyls [M(CO)5·THF] (M = Cr, Mo and W). The reaction of arachno-1 with [Cr(CO)5·THF] resulted in the formation of hetero-trimetallic triply bridging borylene [(Cp*Ru)2(μ-CO)(μ3-CH2S2-κ2S':κ2S''){Cr(CO)3}(μ3-BH)] (2), bridging boryl-borylene [(Cp*Ru)2(μ-CO){(μ3-BH(CH2S2)-κ2B:κ2S':κ1S'')}{Cr(CO)3}(μ3-BH)] (3), and sulfido bridged hetero-trimetallic complex [(Cp*Ru)2(μ-CO)3{Cr(CO)3}(μ3-S)] (4). In 2, one side of Ru2Cr-triangle features a μ3-BH ligand while the other side is quadruply bridged by a methanedithiolato ligand in an unsymmetrical fashion. Unlike 2, in complex 3, one side of the Ru2Cr-triangle has a μ3-BH ligand while the opposite side is bridged by a boryl ligand BH(CH2S2) in an unsymmetrical way (μ3-κ2:κ2:κ1) to the metal centers. Interestingly, when the similar reactions of arachno-1 were performed with heavier group-6 metal carbonyls [M(CO)5·THF] (M = Mo and W), it led to the formation of methanedithiolato bridged hetero-trimetallic chain complexes, [{Cp*Ru(CO)}2(μ-CO)2(μ3-CH2S2-κ2S':κ2S''){M(CO)2}] (5, M = Mo; 6, M = W) and sulfido-bridged hetero-trimetallic complexes [(Cp*Ru)2(μ-CO)3{M(CO)3}(μ3-S)] (7, M = Mo; 8, M = W), analogous to 4. In complexes 5 and 6, a Ru2M-chain is symmetrically bridged by a methanedithiolato ligand. On the other hand, in complexes 4, 7, and 8, a sulfido ligand coordinates to two ruthenium and one group-6 metal atoms in μ3-fashion. All the complexes have been characterized by 1H NMR, 13C NMR, UV-vis, IR spectroscopy, and mass spectrometry and their structural architectures have been unambiguously established by single crystal X-ray diffraction studies. In addition, theoretical investigations provided valuable insights into their electronic structures and bonding properties.

Enhancing Intrinsic Magnetic Hardness by Modulating Antagonistic Interactions in the Rare-Earth-Free Magnetic Solid Solution Hf2 Fe1-δ Ru5-x Irx+δ B2

The quinary members in the solid solution Hf2 Fe1-δ Ru5-x Irx+δ B2 (x=1-4, VE=63-66) have been investigated experimentally and computationally. They were synthesized via arc-melting and analyzed by EDX and X-ray diffraction. Density functional theory (DFT) calculations predicted a preference for magnetic ordering in all members, but with a strong competition between ferro- and antiferromagnetism arising from interchain Fe-Fe interactions. The spin exchange and magnetic anisotropy energies predicted the lowest magnetic hardness for x=1 and 3 and the highest for x=2. Magnetization measurements confirm the DFT predictions and demonstrate that the antiferromagnetic ordering (TN =55-70 K) found at low magnetic fields changed to ferromagnetic (TC =150-750 K) at higher fields, suggesting metamagnetic behavior for all samples. As predicted, Hf2 FeRu3 Ir2 B2 has the highest intrinsic coercivity (Hc =74 kA/m) reported to date for Ti3 Co5 B2 -type phases. Furthermore, all coercivities outperform that of ferromagnetic Hf2 FeIr5 B2 , indicating the importance of AFM interactions in enhancing magnetic anisotropy in these materials. Importantly, two members (x=1 and 4) maintain intrinsic coercivities in the semi-hard range at room temperature. This study opens an avenue for controlling magnetic hardness by modulating antagonistic AFM and FM interactions in low-dimensional rare-earth-free magnetic materials.

Voice Pathologies and the General Population's Perception

OBJECTIVES

To examine how the general population perceives voice pathology based on subjective qualities.

STUDY DESIGN

Descriptive, cross-sectional, survey-based study.

METHODS

This is an IRB-approved Qualtrics survey on Amazon MTurk for respondents ages 18 and older. Ten subjects with voice pathologies supplied voice recordings of the Rainbow Passage to be assessed by the respondents. Respondents then assessed the voice conditions on perceived qualities of intelligence, leadership ability, and employability. One-way analysis of variance (ANOVA) and Dunnett's multiple comparison test with Sidak correction compared the mean scores of the samples (alpha = 0.05).

RESULTS

A total of 1754 responses were included in the final dataset. The female control voice was scored as more likely to be a Fortune 500 leader as well as more intelligent, friendly, attractive, and employable when compared to the female vocal fry and muscle tension dysphonia (MTD) recordings (P < 0.0001). Conversely, the male MTD was the only male pathology that received a significantly lower score on friendliness, attractiveness, Fortune 500 leader status and employability than the male control (P = 0.0102, P = 0.0007, P = 0.0338, and P = 0.0039, respectively).

CONCLUSIONS

This study demonstrates the more critical appraisal of voice pathologies of female patients compared to their male counterparts. People with voice disorders are perceived as being less successful, a disadvantage to potential leadership and career opportunities.

Emotional well-being and HbA1c following the implementation of the Diabetes Psychosocial Assessment Tool (DPAT) in young adults with Type 1 Diabetes (T1DM): An observational study

AIMS

This observational study evaluated the implementation of the Diabetes Psychosocial Assessment Tool (DPAT), assessing emotional well-being of young adults with type 1 diabetes (T1DM) and the clinical congruency between DPAT-recommended and specialist-led referrals.

METHODS

Young adults with T1DM attending the clinic completed the DPAT on two occasions. The DPAT includes the PAID (diabetes distress), PHQ-4 (depression/anxiety) and WHO-5 (general well-being), a diabetes health audit and a referral pathway to (allied) health professionals. Demographic and clinical information was retrieved from medical records. Data was analyzed using descriptive statistics and generalized estimating equations.

RESULTS

115 people with T1DM, aged 16-25 years, were included in the analysis. Symptoms of moderate-severe diabetes distress were present in 29 (25%) participants, symptoms of depression/anxiety and impaired well-being in 21 (19%) and 26 (23%) participants, respectively. The odds of depression/anxiety symptoms was lower at the second timepoint compared to the first timepoint (OR 0.55, 95% CI 0.32-0.96, p=0.03). The odds of moderate-severe diabetes distress tended to be lower. No change was observed in general well-being or HbA1c. There was moderate concordance between DPAT and clinician referrals to psychologists (81%) and dieticians (70%).

CONCLUSIONS

Using the DPAT facilitates the conversation about emotional well-being during routine consultation and follow-up.

Phase I/II study of axitinib (axi) and nivolumab (nivo) in patients with metastatic renal cell carcinoma (mRCC)

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Background: Drug combinations targeting vascular endothelial growth factor (VEGF) and the programmed death one (PD-1) pathway have demonstrated encouraging efficacy in patients (pts) with mRCC. We are conducting a phase I/II trial combining the VEGF-targeting tyrosine kinase inhibitor (TKI) axi and the PD-1 inhibitor nivo in mRCC pts. Methods: The phase I portion of this investigator-initiated, multi-center trial enrolled pts with TKI-refractory mRCC (any line) and no prior anti-PD-1. It used a 3+3 design, with axi dosing starting at 3 mg orally BID, escalating to a target dose of5 mg BID. Nivo dosing was fixed at 240 mg IV Q2 weeks or 480 mg Q4 weeks. Eligible pts received axi alone for a one week induction, followed by combination dosing. There was a 4 week period to assess for dose limiting toxicities (DLTs). The primary endpoint for phase I was safety and establishment of a recommended phase II dose (RP2D) for axi. Safety and early efficacy data for the phase I cohort are presented. Results: Twelve pts received treatment during the phase I portion, with all evaluable for toxicity. Ten were 2nd line and 2 were 3rd line or beyond. One DLT was noted in the first cohort of three pts (grade 3 autoimmune disorder), thus that cohort was expanded. No further DLTs were reported at axi 3 mg BID, or at further expansion to 5 mg BID. Grade 3 adverse events (AEs) at least possibly related to one of the drugs included expected side effects HTN, hyperglycemia, and transaminitis. One patient received steroids for an immune related AE (grade 3 transaminitis) that resolved to grade 1 with steroids. No grade 4-5 AEs occurred. Axi at 5 mg BID was chosen as the RP2D. With 10 pts evaluable for efficacy, 4 pts had partial responses, 4 pts had stable disease, and 2 had progressive disease. Updated efficacy data will be presented. Conclusions: The phase I portion of this phase I/II trial has demonstrated expected safety and established 5 mg BID as the RP2D axi dose. This ongoing VEGF TKI/PD1 trial incorporating two drugs already approved for mRCC pts has shown encouraging signs of efficacy and has now expanded to include treatment naïve pts in addition to TKI-refractory pts as part of phase II. Clinical trial information: NCT03172754.