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Abstract: High-temperature X-ray diffraction has been used to investigate the phase stability of lanthanum strontium cobalt oxide (LSC) for a range of materials with the formula La1−x Sr x CoO3−δ (x =0.7, 0.4, and 0.2). The stability of LSC increases with La content in low oxygen partial pressures at high temperature. Oxygen vacancy ordering has been observed for all three compositions in either low oxygen pressure or under reducing gas, as evidenced by the formation of the brownmillerite phase. The crystal structure of the vacancy-ordered phase was determined using Rietveld analysis of synchrotron X-ray diffraction data. The decomposition products under low oxygen pressure and in reducing conditions have been identified and characterized, including the phase transition and thermal expansion of the primary decomposition products, LaSrCoO4 and LaSrCoO3.5. [Copyright &y& Elsevier]

Boundary-layer transition on axisymmetric bodies at a nonzero angle of attack in Mach 2 supersonic flow was investigated using experimental measurements and linear stability analysis. Transition over four axisymmetric bodies (namely, the Sears-Haack body, the semi-Sears-Haack body, the straight cone, and the flared cone) with different axial pressure gradients was measured in two different facilities with different unit Reynolds numbers. The semi-Sears-Haack body and flared cone were designed specifically to achieve a broader range of axial pressure distributions. Measurements revealed a dramatic effect of body shape on transition behavior near the leeward plane of symmetry. For a body shape with an adverse pressure gradient (that is, a flared cone), the measured transition patterns show an earlier transition location along the leeward symmetry plane in comparison with the neighboring azimuthal locations. For a nearly zero pressure gradient (that is, the straight cone), such leeward-first transition is observed only at the larger unit Reynolds number. Finally, transition occurs farther downstream along the leeward plane for the remaining two body shapes with a favorable pressure gradient. The observed transition patterns are partially consistent with the numerical predictions based on linear stability analysis. [ABSTRACT FROM AUTHOR]

The mechanism of alkane C-H bond activation in heterogeneous acid catalysis is unknown. ¹H solid-state NMR techniques have been used to simultaneously detect the reactivity of both catalyst and alkane reactant protons in a true in-situ experimental design. Specifically, the activation of isobutane C-H bonds by the solid acid zeolite HZSM-5 is directly observed, and the rate of proton transfer between the solid catalyst surface and gaseous isobutane is quantitatively measured using isotopic ¹H/²H exchange methods. An observable adsorption complex forms between the isobutane and the primary Bronsted acid site of ZSM-5, which leads to proton exchange between the zeolite surface and the isobutane methyl groups at temperatures (273 K) much lower than previously reported. The secondary acid site in ZSM-5 is less accessible to or less reactive with the isobutane molecule. Simultaneous detection of protium loss from the Bronsted acid site and protium gain by perdeuterated isobutane reveals a common rate constant equal to 4.1-4.6 x 10-4S-1 at 298 K, but at lower temperatures, the transition between this and a much slower rate process is resolved. The measured activation energy for isobutane H/D exchange is 57 kJ/mol. In all experiments, the isobutane reagent was purified to eliminate any unsaturated impurities that might serve as initiators for carbenium-ion mechanisms, and the active catalyst was free of any organic contaminants that might serve as a source of unsaturated initiators. In total, our results are consistent with direct proton exchange between the zeolite surface and the methyl groups of isobutane. [ABSTRACT FROM AUTHOR]

Objectives: B-cell acute lymphoblastic leukemia (B-ALL) is the most prevalent cancer in United States children. In recent years, immunotherapies using chimeric antigen receptors (CAR T-cells) have improved prognosis for patients with B-ALL. Previous CAR T therapies have used CD19 as a target, but loss of this protein through antigen escape may cause relapse with slim chance of remission. For patients facing relapsed/refractory B-ALL, the need for new targets is evident. In this review, we focus on the KMT2A, IKZF1-related, and DUX4r subgroups of B-ALL, highlighting proven and potential CAR T targets. With a focus on genetics, we discuss chondroitin sulfate proteoglycan 4 as a target in mixed lineage rearranged leukemia and the use of proteomic analysis to locate other B-ALL antigenic surface markers, including the targeting of CD72 within a nanobody-based framework. Additionally, we examine the thymic stromal lymphopoietin receptor as a target in B-ALL with IKAROS family zinc finger 1 deletion across various subgroups. Following this, we propose the adaptation of CD371 as a CAR T-cell target for relapsed/refractory DUX4r B-ALL in the context of promising results from studies in acute myeloid leukemia. Finally, we provide a brief overview of other relevant therapies, including tyrosine kinase inhibitors and a planned universal CAR T for off-the-shelf use, before concluding with a case study that emphasizes the necessity of novel CAR T targets., (Copyright© by the Association of Genetic Technologists.)

Current needs for extending zeolite catalysts beyond traditional gas-phase hydrocarbon chemistry demand detailed characterization of active site structures, distributions, and hydrothermal impacts. A broad suite of homonuclear and heteronuclear NMR correlation experiments on dehydrated H-ZSM-5 catalysts with isotopically enriched 17 O frameworks reveals that at least two types of paired active sites exist, the amount of which depends on the population of fully framework-coordinated tetrahedral Al (Al(IV)-1) and partially framework-coordinated tetrahedral Al (Al(IV)-2) sites, both of which can be denoted as (SiO) 4- n -Al(OH) n . The relative amounts of Al(IV)-1 and Al(IV)-2 sites, and subsequent pairing, cannot be inferred from the catalyst Si/Al ratio, but depend on synthetic and postsynthetic modifications. Correlation experiments demonstrate that, on average, acidic hydroxyl groups from Al(IV)-1/Al(IV)-2 pairs are closer to one another than those from Al(IV)-1/Al(IV)-1 pairs, as supported by computational DFT calculations. Through-bond and through-space polarization transfer experiments exploiting 17 O nuclei reveal a number of different acidic hydroxyl groups in varying Si/Al catalysts, the relative amounts of which change following postsynthetic modifications. Using room-temperature isotopic exchange methods, it was determined that 17 O was homogeneously incorporated into the zeolite framework, while 17 O → 27 Al polarization transfer experiments demonstrated that 17 O incorporation does not occur for extra-framework Al n O m species. Data from samples exposed to controlled hydrolysis indicates that nearest neighbor Al pairs in the framework are more susceptible to hydrolytic attack. The data reported here suggest that Al(IV)-1/Al(IV)-2 paired sites are synergistic sites leading to increased reactivity in both low- and high-temperature reactions. No evidence was found for paired framework/nonframework sites.

The structure of aluminum-containing moieties in and within zeolite H-ZSM-5 catalysts is a complex function of the elemental composition of the catalyst, synthesis conditions, exposure to moisture, and thermal history. 27 Al NMR data collected at field strengths ranging from 7.05 to 35.2 T, i.e., 1 H Larmor frequencies from 300 to 1500 MHz, reveal that Al primarily exists as framework or partially coordinated framework species in commercially available dehydrated H-ZSM-5 catalysts with Si/Al ranging from 11.5 to 40. Quantitative direct-excitation and sensitivity-enhanced 27 Al NMR techniques applied over the wide range of magnetic field strengths used in this study show that prior to significant hydrothermal exposure, detectable amounts of nonframework Al species do not exist. Two-dimensional 27 Al multiple-quantum magic-angle spinning (MQMAS) along with 1 H- 27 Al and 29 Si- 27 Al dipolar correlation (D-HMQC) NMR experiments confirm this conclusion and show that generation of nonframework species following varying severities of hydrothermal exposure are clearly resolved from partially coordinated framework sites. The impact of hydration on the appearance and interpretation of conventional direct-excitation 27 Al spectra, commonly used to assess framework and nonframework Al, is discussed. Aluminum sites in dehydrated catalysts, which are representative of typical operating conditions, are characterized by large quadrupole interactions and are best assigned by obtaining data at multiple field strengths. On the basis of the results here, an accurate initial assessment of Al sites in high-Al content MFI catalysts prior to any hydrothermal treatment can be used to guide reaction conditions, anticipate potential water impacts, and identify contributions from hydroxyl groups other than those associated with the framework bridging acid site.

Objective: To assess the efficacy of tizanidine hydrochloride versus placebo as adjunctive prophylactic therapy for chronic daily headache (chronic migraine, migrainous headache, or tension-type headache)., Background: Tizanidine is an alpha2-adrenergic agonist that inhibits the release of norepinephrine at both the spinal cord and brain, with antinociceptive effects that are independent of the endogenous opioid system. Previous open-label studies have suggested the drug may be effective for treatment of chronic daily headache., Methods: Two hundred patients completed a 4-week, single-blind, placebo baseline period, with 134 fulfilling selection criteria and then randomized to tizanidine or placebo. Ninety-two patients completed at least 8 weeks of treatment (tizanidine, n = 45; placebo, n = 47), and 85 patients completed 12 weeks of treatment (tizanidine, n = 44; placebo, n = 41). Most patients (77%) met the diagnostic criteria for migraine of the International Headache Society; 23% had either chronic migrainous headache or chronic tension-type headache. Tizanidine was slowly titrated over 4 weeks to 24 mg or the maximum dose tolerated (mean, 18 mg; SD, 6.4; median, 20.0; range, 2 to 24), divided equally over three dose intervals per day. Overall headache index ([headache days x average intensity x duration in hours]/28 days) was the primary end point., Results: Tizanidine was shown to be superior to placebo in reducing the overall headache index (P =.0025), as well as mean headache days per week (P =.0193), severe headache days per week (P =.0211), average headache intensity (P =.0108), peak headache intensity (P =.0020), and mean headache duration (P =.0127). The mean percentage improvement during the last 4 weeks of treatment with tizanidine versus placebo was 54% versus 19% for the headache index (P =.0144), 55% versus 21% for severe headache days (P =.0331), 35% versus 19% for headache duration (P =.0142), 35% versus 20% for peak headache intensity (P =.0106), 33% versus 20% for average headache intensity (P =.0281), and 30% versus 22% for total headache days (P =.0593). Patients receiving tizanidine also scored higher ratings of overall headache improvement on a visual analog scale (P =.0069). There was no statistically significant difference in outcome for patients with chronic migraine versus those with only migrainous or tension-type headache. Adverse effects reported by more than 10% of the patients included somnolence (47%), dizziness (24%), dry mouth (23%), and asthenia (19%). Dropouts due to adverse events did not differ significantly between tizanidine and placebo., Conclusions: The results support tizanidine as an effective prophylactic adjunct for chronic daily headache, including migraine, migrainous headache, and tension-type headache. These results also suggest the possible importance of an alpha2-adrenergic mechanism underlying the pathophysiology of this spectrum of headache disorders.