Crystal Growth and Physical Properties of Hybrid CoSn-YCo6Ge6 Structure Type LnxCo3(Ge1-ySny)3 (Ln = Y, Gd).

There is an ongoing interest in kagome materials because they offer tunable platforms at the intersection of magnetism and electron correlation. Herein, we examine single crystals of new kagome materials, LnxCo3(Ge1-ySny)3 (Ln = Y, Gd; y = 0.11, 0.133), which were produced using the Sn flux-growth method. Unlike many of the related chemical analogues with the LnM6X6 formula (M = transition metal and X = Ge, Sn), the Y and Gd analogues crystallize in a hybrid YCo6Ge6/CoSn structure, with Sn substitution. While the Y analogue displays temperature-independent paramagnetism, magnetic measurements of the Gd analogue reveal a magnetic moment of 8.48 µB, indicating a contribution from both Gd and Co. Through anisotropic magnetic measurements, the direction of Co-magnetism can be inferred to be in plane with the kagome net, as the Co contribution is only along H//a. Crystal growth and structure determination of YxCo3(Ge,Sn)3 and GdxCo3(Ge,Sn)3, two new hybrid kagome materials of the CoSn and YCo6Ge6 structure types. Magnetic properties, heat capacity, and resistivity on single crystals are reported.

Developing a deep learning natural language processing algorithm for automated reporting of adverse drug reactions.

The detection of adverse drug reactions (ADRs) is critical to our understanding of the safety and risk-benefit profile of medications. With an incidence that has not changed over the last 30 years, ADRs are a significant source of patient morbidity, responsible for 5%-10% of acute care hospital admissions worldwide. Spontaneous reporting of ADRs has long been the standard method of reporting, however this approach is known to have high rates of under-reporting, a problem that limits pharmacovigilance efforts. Automated ADR reporting presents an alternative pathway to increase reporting rates, although this may be limited by over-reporting of other drug-related adverse events. We developed a deep learning natural language processing algorithm to identify ADRs in discharge summaries at a single academic hospital centre. Our model was developed in two stages: first, a pre-trained model (DeBERTa) was further pre-trained on 1.1 million unlabelled clinical documents; secondly, this model was fine-tuned to detect ADR mentions in a corpus of 861 annotated discharge summaries. This model was compared to a version without the pre-training step, and a previously published RoBERTa model pretrained on MIMIC III, which has demonstrated strong performance on other pharmacovigilance tasks. To ensure that our algorithm could differentiate ADRs from other drug-related adverse events, the annotated corpus was enriched for both validated ADR reports and confounding drug-related adverse events using. The final model demonstrated good performance with a ROC-AUC of 0.955 (95% CI 0.933 - 0.978) for the task of identifying discharge summaries containing ADR mentions, significantly outperforming the two comparator models.

Comparing GENEActiv against Actiwatch-2 over Seven Nights Using a Common Sleep Scoring Algorithm and Device-Specific Wake Thresholds.

Demonstrating inter-device reliability is essential to use devices interchangeably, and accurately integrate, interpret, or compare data from different actigraphs. Despite this, there is a paucity of comparative literature over a timeframe exceeding one night. The aims of this study were to determine an optimal wake threshold for GENEActiv and to evaluate the concordance between Actiwatch-2 and GENEActiv using a common algorithm (Phillips Respironics). Data were collected from 33 individuals (20 female) aged 20-35 years (M= 25.33, SD = 4.69) across a total 213 nights. Participants wore both devices simultaneously and continuously for seven days. The sleep parameters of interest were: total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset. Exploratory analyses of sensitivity, specificity, overall accuracy, mean bias, and paired samples t-tests indicated an optimal wake threshold of 115 for GENEActiv, compared with Actiwatch-2 at the 40 (medium, default) threshold. Using these thresholds, sensitivity, and overall accuracy of GENEActiv were both good (86% and 78%, respectively), however specificity was relatively low (40%). There were no significant inter-device differences for any sleep parameters, and all absolute mean biases were small. Overall, the findings from this study provide the first empirical evidence to support the reliability of GENEActiv against Actiwatch-2 over multiple nights using a common algorithm with device-specific wake thresholds.

It Runs in the BaAl4 Family: Relating the Structure and Properties of Middle Child Ln2Co3Ge5 (Ln = Pr, Nd, and Sm) to its Siblings LnCo2Ge2 and LnCoGe3.

The BaAl4 prototype structure and its derivatives have been identified to host several topological quantum materials and noncentrosymmetric superconductors. Single crystals up to ∼3 mm × 3 mm × 5 mm of Ln2Co3Ge5 (Ln = Pr, Nd, and Sm) are obtained via flux growth utilizing Sn as metallic flux. The crystal structure is isostructural to the Lu2Co3Si5 structure type in the crystallographic space group C2/c. The temperature-dependent magnetization indicates magnetic ordering at 30 K for all three compounds. Pr2Co3Ge5 and Nd2Co3Ge5 exhibit complex magnetic behavior with spin reorientations before ordering antiferromagnetically around 6 K, whereas Sm2Co3Ge5 shows a clear antiferromagnetic behavior at 26 K. The structures and properties of Ln2Co3Ge5 (Ln = Pr, Nd, and Sm) are compared to those of the ThCr2Si2 and BaNiSn3 structure types. Herein, we present the optimized crystal growth, structure, and physical properties of Ln2Co3Ge5 (Ln = Pr, Nd, and Sm).

Antiferromagnetic Order and Spin-Canting Transition in the Corrugated Square Net Compound Cu3(TeO4)(SO4)·H2O.

Strongly correlated electrons in layered perovskite structures have been the birthplace of high-temperature superconductivity, spin liquids, and quantum criticality. Specifically, the cuprate materials with layered structures made of corner-sharing square-planar CuO4 units have been intensely studied due to their Mott insulating ground state, which leads to high-temperature superconductivity upon doping. Identifying new compounds with similar lattice and electronic structures has become a challenge in solid-state chemistry. Here, we report the hydrothermal crystal growth of a new copper tellurite sulfate, Cu3(TeO4)(SO4)·H2O, a promising alternative to layered perovskites. The orthorhombic phase (space group Pnma) is made of corrugated layers of corner-sharing CuO4 square-planar units that are edge-shared with TeO4 units. The layers are linked by slabs of corner-sharing CuO4 and SO4. Using both the bond valence sum analysis and magnetization data, we find purely Cu2+ ions within the layers but a mixed valence of Cu2+/Cu+ between the layers. Cu3(TeO4)(SO4)·H2O undergoes an antiferromagnetic transition at TN = 67 K marked by a peak in the magnetic susceptibility. Upon further cooling, a spin-canting transition occurs at T* = 12 K, evidenced by a kink in the heat capacity. The spin-canting transition is explained on the basis of a J1-J2 model of magnetic interactions, which is consistent with the slightly different in-plane superexchange paths. We present Cu3(TeO4)(SO4)·H2O as a promising platform for the future doping and strain experiments that could tune the Mott insulating ground state into superconducting or spin liquid states.

Fantastic n = 4: Ce5Co4+xGe13-ySny of the An+1MnX3n+1 homologous series.

Ce-based intermetallics are of interest due to the potential to study the interplay of localized magnetic moments and conduction electrons. Our work on Ce-based germanides led to the identification of a new homologous series An+1MnX3n+1 (A = rare earth, M = transition metal, X = tetrels, and n = 1-6). This work presents the single-crystal growth, structure determination, and anisotropic magnetic properties of the n = 4 member of the Cen+1ConGe3n+1 homologous series. Ce5Co4+xGe13-ySny consists of three Ce sites, three Co sites, seven Ge sites, and two Sn sites, and the crystal structure is best modeled in the orthorhombic space group Cmmm where a = 4.3031(8) Å, b = 45.608(13) Å, and c = 4.3264(8) Å, which is in close agreement with the previously reported Sn-free analog where a = 4.265(1) Å, b = 45.175(9) Å, and c = 4.293(3) Å. Anisotropic magnetic measurements show Kondo-like behavior and three magnetic transitions at 6, 4.9, and 2.4 K for Ce5Co4+xGe13-ySny.

Crystal Structure and Electronic Properties of New Compound Zr6.5Pt6Se19.

A new ternary nonstoichiometric Zr6.5Pt6Se19 has been discovered as a part of effort to dope Zr into the layered transitional metal chalcogenide PtSe2. With a new structure type (oC68), it is the first Pt-based ternary chalcogenide with group 4 elements (Ti, Zr, and Hf). The crystal structure adopts the orthorhombic space group Cmmm with lattice parameters of a = 15.637(6) Å, b = 26.541(10) Å, c = 3.6581(12) Å, and V = 1518.2(9) Å3. This unusual structure consists of several building units: chains of edge-sharing selenium trigonal prisms and octahedra centered by zirconium atoms, chains of corner-shared square pyramid, and square planar centered by Pt atoms. The condensation of these building blocks forms a unique structure with bilayered Zr5.54Pt6Se19 slabs stacking along the b direction and large channels parallel to the c direction within the bilayered slabs. Band structure calculations suggest that partial occupancy of Zr atoms creates a pseudo gap at the Fermi level and is likely the main cause for the stability of this new phase.

Casting a Wider Net: Rational Synthesis Design of Low-Dimensional Bulk Materials.

The discovery of novel magnetic and electronic properties in low-dimensional materials has led to the pursuit of hierarchical materials with specific substructures. Low-dimensional solids are highly anisotropic by nature and show promise in new quantum materials leading to exotic physical properties not realized in three-dimensional materials. We have the opportunity to extend our synthetic strategy of the flux-growth method to designing single crystalline low-dimensional materials in bulk. The goal of this Account is to highlight the synthesis and physical properties of several low-dimensional intermetallic compounds containing specific structural motifs that are linked to desirable magnetic and electrical properties. We turned our efforts toward intermetallic compounds consisting of antimony nets because they are closely linked to properties such as high carrier mobility (the velocity of an electron moving through a material under a magnetic field) and large magnetoresistance (the change in resistivity with an applied magnetic field), both of which are desirable properties for technological applications. The SmSb2 structure type is of particular interest because it is comprised of rectangular antimony nets and rare earth ions stacked between the antimony nets in a square antiprismatic environment. LnSb2 (Ln = La-Nd, Sm) have been shown to be highly anisotropic with SmSb2 exhibiting magnetoresistance of over 50000% for H∥c axis and ∼2400% for H∥ab. Using this structure type as an initial building block, we envision the insertion of transition metal substructures into the SmSb2 structure type to produce ternary materials. We describe compounds adopting the HfCuSi2 structure type as an insertion of a tetrahedral transition metal-antimony subunit into the LnSb2 host structure. We studied LnNi1-xSb2 (Ln = Y, Gd-Er), where positive magnetoresistance reaching above 100% was found for the Y, Gd, and Ho analogues. We investigated the influence of the transition metal sublattice by substituting Ni into Ce(Cu1-xNix)ySb2 (y < 0.8) and found that the material is highly anisotropic and metamagnetic transitions appear at ∼0.5 and 1 T in compounds with higher Ni concentration. Metamagnetism is characterized by a sharp increase in the magnetic response of a material with increasing applied magnetic field, which was also observed in LnSb2 (Ln = Ce-Nd). We also endeavored to study materials that possess a transition metal sublattice with the potential for geometric frustration. An example is the La2Fe4Sb5 structure type, which consists of antimony square nets and an iron-based network arranged in nearly equilateral triangles, a feature found in magnetically frustrated systems. We discovered spin glass behavior in Ln2Fe4Sb5 (Ln = La-Nd, Sm) and evidence that the transition metal sublattice contributes to the magnetic interactions of Ln2Fe4Sb5. We investigated the magnetic properties of Pr2Fe4-xCoxSb5 (x < 2.3) and found that as the Co concentration increases, a second magnetic transition leads from a localized to an itinerant system. The La2Fe4Sb5 structure type is quite robust and allows for the incorporation of other transition metals, thereby making it an excellent candidate to study competing magnetic interactions in lanthanide-containing intermetallic compounds. In this manuscript, we aim to share our experiences of bulk intermetallic compounds to inspire the development of new low-dimensional materials.

Synthesis and Structure of a Nonstoichiometric Zr3.55Pt4Sb4 Compound.

A nonstoichiometric ternary antimonide, Zr3.55Pt4Sb4, with a new structure type (hP24), has been synthesized via arc-melting. Its crystal structure was determined by single-crystal X-ray diffraction with hexagonal space group P63/mmc and lattice parameters a = 4.391(3) Å, c = 30.53(2) Å, and V = 509.7(8) Å3. It features the unique Pt4Sb4 slab with Pt-Pt bonds and is reminiscent to hexagonal diamond substructures. Three different Zr atoms, occupying three different sites, aid in the close-packing of the Pt and Sb atoms. Electronic structure calculations show the half occupancy of one Zr site creates a pseudogap at the Fermi level and optimizes the Pt-Sb bonding interactions. This enhances the electronic stability and accounts for the very narrow phase width observed for this nonstoichiometric compound. Furthermore, strong Zr-Pt and Zr-Sb interactions play a crucial role in the chemical bonding of the title compound. Electrical transport measurements show metallic behavior of this compound down to 2 K, consistent with the band structure calculations.

The Role of Crystal Growth Conditions on the Magnetic Properties of Ln2Fe4- xCo xSb5 (Ln = La and Ce).

Single crystals of Ln2Fe4- xCo xSb5- yBi y (Ln = La, Ce; 0 ≤ x < 0.5; 0 ≤ y ≤ 0.2) were grown using Bi flux and self-flux methods. The compounds adopt the La2Fe4Sb5 structure type with tetragonal space group I4/ mmm. The La2Fe4Sb5 structure type is comprised of rare earth atoms capping square Sb nets in a square antiprismatic fashion and two transition-metal networks forming a PbO-type layer with Sb and transition-metal isosceles triangles. Substituting Co into the transition-metal sublattice results in a decrease in the transition temperature and reduced frustration, indicative of a transition from localized to itinerant behavior. In this manuscript, we demonstrated that Bi can be used as an alternate flux to grow single crystals of antimonides. Even with the incorporation of Bi into the Sb square net, the magnetic properties are not significantly affected. In addition, we have shown that the incorporation of Co into the Fe triangular sublattice leads to an itinerant magnetic system.

Law and Disorder: Special Stacking Units-Building the Intergrowth Ce6Co5Ge16.

A new structure type of composition Ce6Co5Ge16 was grown out of a molten Sn flux. Ce6Co5Ge16 crystallizes in the orthorhombic space group Cmcm, with highly anisotropic lattice parameters of a = 4.3293(5) Å, b = 55.438(8) Å, and c = 4.3104(4) Å. The resulting single crystals were characterized by X-ray diffraction, and the magnetic and transport properties are presented. The Sn-stabilized structure of Ce6Co5Ge16 is based on the stacking of disordered Ce cuboctahedra and is an intergrowth of existing structure types including AlB2, BaNiSn3, and AuCu3. The stacking of structural subunits has previously been shown to be significant in the fields of superconductivity, quantum materials, and optical materials. Herein, we present the synthesis, characterization, and complex magnetic behavior of Ce6Co5Ge16 at low temperature, including three distinct magnetic transitions.

Targeted crystal growth of rare Earth intermetallics with synergistic magnetic and electrical properties: structural complexity to simplicity.

The single-crystal growth of extended solids is an active area of solid-state chemistry driven by the discovery of new physical phenomena. Although many solid-state compounds have been discovered over the last several decades, single-crystal growth of these materials in particular enables the determination of physical properties with respect to crystallographic orientation and the determination of properties without possible secondary inclusions. The synthesis and discovery of new classes of materials is necessary to drive the science forward, in particular materials properties such as superconductivity, magnetism, thermoelectrics, and magnetocalorics. Our research is focused on structural characterization and determination of physical properties of intermetallics, culminating in an understanding of the structure-property relationships of single-crystalline phases. We have prepared and studied compounds with layered motifs, three-dimensional magnetic compounds exhibiting anisotropic magnetic and transport behavior, and complex crystal structures leading to intrinsically low lattice thermal conductivity. In this Account, we present the structural characteristics and properties that are important for understanding the magnetic properties of rare earth transition metal intermetallics grown with group 13 and 14 metals. We present phases adopting the HoCoGa5 structure type and the homologous series. We also discuss the insertion of transition metals into the cuboctahedra of the AuCu3 structure type, leading to the synthetic strategy of selecting binaries to relate to ternary intermetallics adopting the Y4PdGa12 structure type. We provide examples of compounds adopting the ThMn12, NaZn13, SmZn11, CeCr2Al20, Ho6Mo4Al43, CeRu2Al10, and CeRu4Al16-x structure types grown with main-group-rich self-flux methods. We also discuss the phase stability of three related crystal structures containing atoms in similar chemical environments: ThMn12, CaCr2Al10, and YbFe2Al10. In addition to dimensionality and chemical environment, complexity is also important in materials design. From relatively common and well-studied intermetallic structure types, we present our motivation to work with complex stannides adopting the Dy117Co57Sn112 structure type for thermoelectric applications and describe a strategy for the design of new magnetic intermetallics with low lattice thermal conductivity. Our quest to grow single crystals of rare-earth-rich complex stannides possessing low lattice thermal conductivity led us to discover the new structure type Ln30Ru4+xSn31-y (Ln = Gd, Dy), thus allowing the correlation of primitive volumes with lattice thermal conductivities. We highlight the observation that Ln30Ru4+xSn31-y gives rise to highly anisotropic magnetic and transport behavior, which is unexpected, illustrating the need to measure properties on single crystals.

Emergence of Magnetic States in Pr2Fe(4-x)Co(x)Sb5 (1 < x < 2.5).

Single crystals of Pr2Fe(4-x)Co(x)Sb5 (1 < x < 2.5) were grown from a Bi flux and characterized by X-ray diffraction. The compounds adopt the La2Fe4Sb5 structure type (I4/mmm). The structure of Pr2Fe(4-x)Co(x)Sb5 (1 < x < 2.5) contains a network of transition metals forming isosceles triangles. The x ∼ 1 analogue is metallic and exhibits a magnetic transition at T1 ≈ 25 K. The magnetic moment obtained from the Curie-Weiss fit is 11.49(4) µ(B), which is larger than the spin-only Pr(3+) moment. The x ∼ 2 analogue orders magnetically at T1 ≈ 80 and T2 ≈ 45 K. This is the first case of the substitution of Co into the La2Fe4Sb5 structure type, evidenced by the increased concentration of dopant with decreased lattice parameters coupled with a change in the transition temperature with a change in the cobalt concentration. The added complexity in the magnetic behavior of the x ∼ 1 and 2 analogues indicates that the increased concentration of Co invokes an additional magnetic contribution of the transition metal in the sublattice. Furthermore, X-ray photoelectron spectroscopy measurements support the change in the oxidation states of transition metals with increasing cobalt concentration.

Common drive to the upper airway muscle genioglossus during inspiratory loading.

Common drive is thought to constitute a central mechanism by which the efficiency of a motor neuron pool is increased. This study tested the hypothesis that common drive to the upper airway muscle genioglossus (GG) would increase with increased respiratory drive in response to an inspiratory load. Respiration, GG electromyographic (EMG) activity, single-motor unit activity, and coherence in the 0-5 Hz range between pairs of GG motor units were assessed for the 30 s before an inspiratory load, the first and second 30 s of the load, and the 30 s after the load. Twelve of twenty young, healthy male subjects provided usable data, yielding 77 pairs of motor units: 2 Inspiratory Phasic, 39 Inspiratory Tonic, 15 Expiratory Tonic, and 21 Tonic. Respiratory and GG inspiratory activity significantly increased during the loads and returned to preload levels during the postload periods (all showed significant quadratic functions over load trials, P < 0.05). As hypothesized, common drive increased during the load in inspiratory modulated motor units to a greater extent than in expiratory/tonic motor units (significant load × discharge pattern interaction, P < 0.05). Furthermore, this effect persisted during the postload period. In conclusion, common drive to inspiratory modulated motor units was elevated in response to increased respiratory drive. The postload elevation in common drive was suggestive of a poststimulus activation effect.

The acute effects of alcohol on sleep electroencephalogram power spectra in late adolescence.

BACKGROUND: Alcohol's effect on sleep electroencephalogram (EEG) power spectra during late adolescence is of interest given that this age group shows both dramatic increases in alcohol consumption and major sleep-related developmental changes in quantitative EEG measures. This study examined the effect of alcohol on sleep EEG power spectra in 18- to 21-year-old college students. METHODS: Participants were 24 (12 female) healthy 18- to 21-year-old social drinkers. Participants underwent 2 conditions: presleep alcohol and placebo, followed by standard polysomnography with comprehensive EEG recordings. RESULTS: After alcohol, mean breath alcohol concentration at lights-out was 0.084%. Interaction effects indicated simultaneous increases in frontal non-rapid eye movement sleep (NREM) delta (p = 0.031) and alpha (p = 0.005) power in the first sleep cycles following alcohol consumption which was most prominent at frontal scalp sites (p < 0.001). A decrease in sigma power (p = 0.001) was also observed after alcohol. CONCLUSIONS: As hypothesized, alcohol increased slow wave sleep-related NREM delta power. However, there was a simultaneous increase in frontal alpha power. Results suggest that alcohol may exert an arousal influence which may compete with the sleep maintenance influence of increased delta activity. The phenomenon is similar to, or the same as, alpha-delta sleep which has been associated with the presence of disruptive stimuli during sleep. This may have negative implications for the impact of presleep alcohol consumption on sleep and consequent daytime functioning.

Investigation of Mn, Fe, and Ni incorporation in CeCo2Al8.

Single crystals of CeCo(2-x)M(x)Al(8) (M = Mn, Fe, Ni; 0 ≤ x < 1) were grown and characterized by X-ray diffraction and magnetic susceptibility. The unit cell volumes of Mn-doped compounds increase and those of Ni-doped compounds decrease with increasing dopant concentration. All samples display a magnetic ordering near 6 K with magnetic moments of the analogues ranging from 2.61 to 2.81 µ(B)/mol Ce and slightly higher than Ce(3+) only magnetic moment. The unit cell volumes of Fe-doped compounds also increase with increasing Fe concentration. However, the cell volume of CeCo(2-x)Fe(x)Al(8) decreases for x = 1.00 and is not Curie-Weiss possibly because of valence fluctuation.

International trends in health science librarianship Part 10: The Greater China area.

This is the 10th in a series of articles exploring international trends in health science librarianship. This issue describes developments in health science librarianship in the first decade of the 21st century in China, Hong Kong and Taiwan. The next issue will report on Japan and South Korea. JM.

Much more to explore with an oxidation state of nearly four: Pr valence instability in intermetallic m-Pr2Co3Ge5.

For some intermetallic compounds containing lanthanides, structural transitions can result in intermediate electronic states between trivalency and tetravalency; however, this is rarely observed for praseodymium compounds. The dominant trivalency of praseodymium limits potential discoveries of emergent quantum states in itinerant 4f1 systems accessible using Pr4+-based compounds. Here, we use in situ powder x-ray diffraction and in situ electron energy-loss spectroscopy (EELS) to identify an intermetallic example of a dominantly Pr4+ state in the polymorphic system Pr2Co3Ge5. The structure-valence transition from a nearly full Pr4+ electronic state to a typical Pr3+ state shows the potential of Pr-based intermetallic compounds to host valence-unstable states and provides an opportunity to discover previously unknown quantum phenomena. In addition, this work emphasizes the need for complementary techniques like EELS when evaluating the magnetic and electronic properties of Pr intermetallic systems to reveal details easily overlooked when relying on bulk magnetic measurements alone.