Crystallinity engineering for overcoming the activity-stability tradeoff of spinel oxide in Fenton-like catalysis.

A precise modulation of heterogeneous catalysts in structural and surface properties promises the development of more sustainable advanced oxidation water purification technologies. However, while catalysts with superior decontamination activity and selectivity are already achievable, maintaining a long-term service life of such materials remains challenging. Here, we propose a crystallinity engineering strategy to break the activity-stability tradeoff of metal oxides in Fenton-like catalysis. The amorphous/crystalline cobalt-manganese spinel oxide (A/C-CoMnOx) provided highly active, hydroxyl group-rich surface, with moderate peroxymonosulfate (PMS)-binding affinity and charge transfer energy and strong pollutant adsorption, to trigger concerted radical and nonradical reactions for efficient pollutant mineralization, thereby alleviating the catalyst passivation by oxidation intermediate accumulation. Meanwhile, the surface-confined reactions, benefited from the enhanced adsorption of pollutants at A/C interface, rendered the A/C-CoMnOx/PMS system ultrahigh PMS utilization efficiency (82.2%) and unprecedented decontamination activity (rate constant of 1.48 min-1) surpassing almost all the state-of-the-art heterogeneous Fenton-like catalysts. The superior cyclic stability and environmental robustness of the system for real water treatment was also demonstrated. Our work unveils a critical role of material crystallinity in modulating the Fenton-like catalytic activity and pathways of metal oxides, which fundamentally improves our understanding of the structure-activity-selectivity relationships of heterogeneous catalysts and may inspire material design for more sustainable water purification application and beyond.

Study on the Mechanism of FOXA2 Activation on Glutathione Metabolic Reprogramming Mediated by ETV4 Transcription to Facilitate Colorectal Cancer Malignant Progression.

The metabolic imbalance of glutathione (GSH) has been widely recognized in most cancers, but the specific molecular mechanism of GSH metabolic regulation in the malignant progression of colorectal cancer (CRC) is unexplored. The objective of our project is to elucidate whether ETV4 affects the malignant progression of CRC through GSH metabolic reprogramming. Bioinformatics and molecular experiments measured the expression of ETV4 in CRC, and in vitro experiments explored the impact of ETV4 on CRC malignant progression. The Kyoto Encyclopedia of Genes and Genomes (KEGG) identified the pathway of ETV4 enrichment. The bioinformatics approach identified FOXA2 as an upstream regulatory factor of ETV4. The dual-luciferase assay, chromatin immunoprecipitation (ChIP) and co-immunoprecipitation (Co-IP) experiment verified the binding relationship between ETV4 and FOXA2. Cell viability, migration, and invasion abilities were determined by conducting CCK-8, wound healing, and Transwell assays, respectively. The expression levels of N-cadherin, E-cadherin, and vimentin were determined by utilizing immunofluorescence (IF). Metabolism-related enzymes GCLM, GCLC, and GSTP1 levels were detected to evaluate the GSH metabolism level by analyzing the GSH/GSSG ratio. In vivo experiments were performed to explore the effect of FOXA2/ETV4 on CRC progression, and the expression of related proteins was detected by western blot. ETV4 was highly expressed in CRC. Knocking down ETV4 suppressed CRC cell viability, migration, invasion, and epithelial-mesenchymal transition (EMT) progression in vitro. ETV4 was abundant in the GSH metabolic pathway, and overexpression of ETV4 facilitated CRC malignant progression through activation of the GSH metabolism. In addition, in vitro cellular experiments and in vivo experiments in nude mice confirmed that FOXA2 transcriptionally activated ETV4. Knocking down FOXA2 repressed the malignant phenotype of CRC cells by suppressing GSH metabolism. These effects were reversed by overexpressing ETV4. Our results indicated that FOXA2 transcriptionally activates ETV4 to facilitate CRC malignant progression by modulating the GSH metabolic pathway. Targeting the FOXA2/ETV4 axis or GSH metabolism may be an effective approach for CRC treatment.

Amorphization-Induced Cation Exchange in Indium Oxide Nanosheets for CO2-to-Ethanol Conversion.

Cation exchange (CE) in metal oxides under mild conditions remains an imperative yet challenging goal to tailor their composition and enable practical applications. Herein, we first develop an amorphization-induced strategy to achieve room-temperature CE for universally synthesizing single-atom doped In2O3 nanosheets (NSs). Density functional theory (DFT) calculations elucidate that the abundant coordination-unsaturated sites present in a-In2O3 NSs are instrumental in surmounting the energy barriers of CE reactions. Empirically, a-In2O3 NSs as the host materials successfully undergo exchange with unary cations (Cu2+, Co2+, Mn2+, Ni2+), binary cations (Co2+Mn2+, Co2+Ni2+, Mn2+Ni2+), and ternary cations (Co2+Mn2+Ni2+). Impressively, high-loading single-atom doped (over 10 atom %) In2O3 NSs were obtained. Additionally, Cu/a-In2O3 NSs exhibit an excellent ethanol yield (798.7 µmol g-1 h-1) with a high selectivity of 99.5% for the CO2 photoreduction. This work offers a new approach to induce CE reactions in metal oxides under mild conditions and constructs scalable single-atom doped catalysts for critical applications.

Strong Metal-Support Interaction Triggered by Molten Salts.

Strong metal-support interaction (SMSI) plays a vital role in tuning the geometric and electronic structures of metal species. Generally, a high-temperature treatment (>500 °C) in reducing atmosphere is required for constructing SMSI, which may induce the sintering of metal species. Herein, we use molten salts as the reaction media to trigger the formation of high-intensity SMSI at reduced temperatures. The strong ionic polarization of the molten salt promotes the breakage of Ti-O bonds in the TiO2 support, and hence decreases the energy barrier for the formation of interfacial bonds. Consequently, a high-intensity SMSI state is achieved in TiO2 supported Ir nanoclusters, evidenced by a large number of Ir-Ti bonds at the interface, at a low temperature of 350 °C. Moreover, this method is applicable for triggering SMSI in various supported metal catalysts with different oxide supports including CeO2 and SnO2. This newly developed SMSI construction methodology opens a new avenue and holds significant potential for engineering advanced supported metal catalysts toward a broad range of applications.

Selective and Nongenetic Peroxidase Tag of Membrane Protein: a Nucleic Acid Tool for Proximity Labeling.

The protein nanoenvironment on the plasma membrane is intimately linked to cellular biological functions. Elucidation of the protein nanoenvironment contributes to understanding the pathological mechanism and discovery of disease biomarkers. However, methods enabling characterization of the protein nanoenvironment in the endogenous biological environment have been rarely developed. Toward this end, we created a nucleic acid tool called Apt-Gq/h for proximity labeling to decipher the endogenous protein nanoenvironment. Here, the aptamer acts as an anchor for binding the protein of interest (POI). The G-quadruplex/hemin complex induces proximity labeling of POI via catalyzing the conversion of inert small-molecule substrates into short-lived reactive species. The labeled proteins enable the subsequent affinity-based enrichment and proteomic analysis. We first characterized Apt-Gq/h-mediated POI labeling in vitro and tested its utility by interrogating the protein nanoenvironment of POI in living cells. Taking advantage of the nongenetic, multiple reaction sites, and rapid proximity labeling, Apt-Gq/h was further utilized to imaging the cell-cell connection and amplification detection of biomarkers in living cells and tissue sections. We believe that Apt-Gq/h will be a potential tool for basic science and clinical applications.

DNA-Templated Glycan Labeling for Monitoring Receptor Spatial Distribution in Living Cells.

Tracking the spatial distribution of receptor tyrosine kinases in their native environment contributes to understanding the homeostatic or pathological states at a molecular level. Conjugation of DNA tags to a specific receptor is a powerful tool for monitoring receptor spatial distribution. However, long-term stable trafficking in live cells without interfering with the intrinsic receptor function remains a challenge. Here, we report a general DNA-templated glycan labeling strategy to track spatial distribution of a specific receptor in living cells. Different from existing target-selective covalent methods, the DNA tags were incorporated in glycan of a specific receptor via aptamer-assisted metabolic glycan labeling, thus resulting in minimal perturbation to the receptor's biological function. As proof of concept, covalent tagging of MET, HER2, and EGFR was achieved, and then the spatial distribution was successfully monitored, including homo-/heterodimerization and internalization. Overall, the proposed strategy will greatly aid in investigating receptor dynamics and is conducive to understanding their biological function in the native environment.

LncRNA DNM3OS regulates GREM2 via miR-127-5p to suppress early chondrogenic differentiation of rat mesenchymal stem cells under hypoxic conditions.

BACKGROUND: Improved chondrogenic differentiation of mesenchymal stem cells (MSCs) by genetic regulation is a potential method for regenerating articular cartilage. MiR-127-5p has been reported to promote cartilage differentiation of rat bone marrow MSCs (rMSCs); however, the regulatory mechanisms underlying hypoxia-stimulated chondrogenic differentiation remain unknown. METHODS: rMSCs were induced to undergo chondrogenic differentiation under normoxic or hypoxic conditions. Expression of lncRNA DNM3OS, miR-127-5p, and GREM2 was detected by quantitative real-time PCR. Proteoglycans were detected by Alcian blue staining. Western blot assays were performed to examine the relative levels of GREM2 and chondrogenic differentiation related proteins. Luciferase reporter assays were performed to assess the association among DNM3OS, miR-127-5p, and GREM2. RESULTS: MiR-127-5p levels were upregulated, while DNM3OS and GREM2 levels were downregulated in rMSCs induced to undergo chondrogenic differentiation, and those changes were attenuated by hypoxic conditions (1% O2). Further in vitro experiments revealed that downregulation of miR-127-5p reduced the production of proteoglycans and expression of chondrogenic differentiation markers (COL1A1, COL2A1, SOX9, and ACAN) and osteo/chondrogenic markers (BMP-2, p-SMAD1/2). MiR-127-5p overexpression produced the opposite results in rMSCs induced to undergo chondrogenic differentiation under hypoxic conditions. GREM2 was found to be a direct target of miR-127-5p, which was suppressed in rMSCs undergoing chondrogenic differentiation. Moreover, DNM3OS could directly bind to miR-127-5p and inhibit chondrogenic differentiation of rMSCs via regulating GREM2. CONCLUSIONS: Our study revealed a novel molecular pathway (DNM3OS/miR-127-5p/GREM2) that may be involved in hypoxic chondrogenic differentiation.

Chest CT manifestations of new coronavirus disease 2019 (COVID-19): a pictorial review.

Coronavirus disease 2019 (COVID-19) outbreak, first reported in Wuhan, China, has rapidly swept around the world just within a month, causing global public health emergency. In diagnosis, chest computed tomography (CT) manifestations can supplement parts of limitations of real-time reverse transcription polymerase chain reaction (RT-PCR) assay. Based on a comprehensive literature review and the experience in the frontline, we aim to review the typical and relatively atypical CT manifestations with representative COVID-19 cases at our hospital, and hope to strengthen the recognition of these features with radiologists and help them make a quick and accurate diagnosis.Key Points• Ground glass opacities, consolidation, reticular pattern, and crazy paving pattern are typical CT manifestations of COVID-19.• Emerging atypical CT manifestations, including airway changes, pleural changes, fibrosis, nodules, etc., were demonstrated in COVID-19 patients.• CT manifestations may associate with the progression and prognosis of COVID-19.

Smart Nanocarriers for the Treatment of Retinal Diseases.

Retinal diseases, such as age-related macular degeneration, diabetic retinopathy, and retinoblastoma, stand as the leading causes of irreversible vision impairment and blindness worldwide. Effectively administering drugs for retinal diseases poses a formidable challenge due to the presence of complex ocular barriers and elimination mechanisms. Over time, various approaches have been developed to fabricate drug delivery systems for improving retinal therapy including virus vectors, lipid nanoparticles, and polymers. However, conventional nanocarriers encounter issues related to the controllability, efficiency, and safety in the retina. Therefore, the development of smart nanocarriers for effective or more invasive long-term treatment remains a desirable goal. Recently, approaches have surfaced for the intelligent design of nanocarriers, leveraging specific responses to external or internal triggers and enabling multiple functions for retinal therapy such as topical administration, prolonged drug release, and site-specific drug delivery. This Review provides an overview of prevalent retinal pathologies and related pharmacotherapies to enhance the understanding of retinal diseases. It also surveys recent developments and strategies employed in the intelligent design of nanocarriers for retinal disease. Finally, the challenges of smart nanocarriers in potential clinical retinal therapeutic applications are discussed to inspire the next generation of smart nanocarriers.

CDC25B Is a Prognostic Biomarker Associated With Immune Infiltration and Drug Sensitivity in Hepatocellular Carcinoma.

Cell division cycle 25B (CDC25B), a member of the CDC25 phosphatase family, plays a key role in cell cycle regulation. Studies have suggested its carcinogenic potential in various cancers, but the role of CDC25B in the development of hepatocellular carcinoma (HCC) remains poorly understood. The aim of this study was to clarify the role of CDC25B in HCC using bioinformatics and experiments. CDC25B expression data of HCC cancer tissues and paracancerous normal samples were obtained from The Cancer Gene Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and the relationship between CDC25B expression and the prognosis and degree of tumor differentiation of HCC patients was analyzed. CDC25B expression was verified in clinical HCC tissue samples using fluorescence quantitative polymerase chain reaction (q-PCR) and protein immunoblotting (Western blot). Gene set enrichment analysis (GSEA) was used to identify signaling pathways enriched in CDC25B expression, and differential genes (DEGs) were used to screen out coexpressed hub genes and construct protein-protein interaction (PPI) networks. 5-Ethynyl-2'-deoxyuridine (EDU) staining was used to compare the proliferation and differentiation ability of the HCC cell line (HCC-LM3) after knockdown of CDC25B. Finally, we investigated the mutation of CDC25B in HCC and the relationship between CDC25B expression and tumor cell infiltration of lymphocytes and some immune checkpoints as well as drug sensitivity. CDC25B was overexpressed in HCC tissues and correlated with poor prognosis and the degree of tumor differentiation in patients with HCC. The GSEA and PPI networks together revealed significantly upregulated signaling pathways, as well as functions, associated with the development of HCC when CDC25B was overexpressed. The EDU assay demonstrated that the ability of cells to differentiate value addedly was markedly reduced following the downregulation of CDC25B expression in HCC-LM3s. CDC25B was also involved in the formation of the tumor microenvironment (TME) and immune processes in HCC, and the high expression of CDC25B made patients less sensitive to some drugs. CDC25B can be used as a biomarker and immunotherapeutic target for poor prognosis and partial drug sensitivity in HCC, providing new ideas for HCC treatment.

Vertically Stacked Amorphous Ir/Ru/Ir Oxide Nanosheets for Boosted Acidic Water Splitting.

Integrating multiple functional components into vertically stacked heterostructures offers a prospective approach to manipulating the physicochemical properties of materials. The synthesis of vertically stacked heterogeneous noble metal oxides remains a challenge. Herein, we report a surface segregation approach to create vertically stacked amorphous Ir/Ru/Ir oxide nanosheets (NSs). Cross-sectional high-angle annular darkfield scanning transmission electron microscopy images demonstrate a three-layer heterostructure in the amorphous Ir/Ru/Ir oxide NSs, with IrOx layers located on the upper and lower surfaces, and a layer of RuOx sandwiched between the two IrOx layers. The vertically stacked heterostructure is a result of the diffusion of Ir atoms from the amorphous IrRuOx solid solution to the surface. The obtained A-Ir/Ru/Ir oxide NSs display an ultralow overpotential of 191 mV at 10 mA cm-2 toward acid oxygen evolution reaction and demonstrate excellent performance in a proton exchange membrane water electrolyzer, which requires only 1.63 V to achieve 1 A cm-2 at 60 °C, with virtually no activity decay observed after a 1300 h test.

Amorphous-Crystalline Interface Induced Internal Electric Fields for Electrochromic Smart Window.

Balancing optical modulation and response time is crucial for achieving high coloration efficiency in electrochromic materials. Here, internal electric fields are introduced to titanium dioxide nanosheets by constructing abundant amorphous-crystalline interfaces, ensuring large optical modulation while reducing response time and therefore improving coloration efficiency. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) reveals the presence of numerous amorphous-crystalline phase boundaries in titanium dioxide nanosheets. Kelvin probe force microscopy (KPFM) exhibits an intense surface potential distribution, demonstrating the presence of internal electric fields. Density functional theory (DFT) calculations confirm that the amorphous-crystalline heterointerfaces can generate internal electric fields and reduce diffusion barriers of lithium ions. As a result, the amorphous-crystalline titanium dioxide nanosheets exhibit better coloration efficiency (35.1 cm2 C-1) than pure amorphous and crystalline titanium dioxide nanosheets.

Synergy between Palladium Single Atoms and Nanoparticles via Hydrogen Spillover for Enhancing CO2 Photoreduction to CH4.

Selective photoreduction of carbon dioxide (CO2 ) into carbon-neutral fuels such as methane (CH4 ) is extremely desirable but remains a challenge since sluggish multiple proton-electron coupling transfer and various C1 intermediates are involved. Herein, a synergistic function between single Pd atoms (Pd1 ) and Pd nanoparticles (PdNPs ) on graphitic carbon nitride (C3 N4 ) for photocatalytic CO2 methanation is presented. The catalyst achieves a high selectivity of 97.8% for CH4 production with a yield of 20.3 µmol gcat. -1 h-1 in pure water. Mechanistic studies revealed that Pd1 sites activated CO2 , while PdNPs sites boosted water (H2 O) dissociation for increased H* coverage. The H* produced by PdNPs migrate to the Pd1 sites to promote multiple proton-electron coupling transfer via hydrogen spillover. Moreover, the adjacent Pd1 and PdNPs effectively stabilized intermediates such as *CHO, thereby favoring the pathway for CH4 production. This work provides a new perspective into the development of selective photocatalytic CO2 conversion through the artful design of synergistic catalytic sites.

Reversing the Catalytic Selectivity of Single-Atom Ru via Support Amorphization.

Supported single-atom catalysts (SACs), with the extremely homogenized active sites could achieve high hydrogenation selectivity toward one of the functional groups coexisting in the reactant molecule. However, as to the target group, the control of selective recognition and activation by SACs still remains a challenge. Herein, the phase engineering of the support is adopted to control the chemo-recognition behavior of SACs in selective hydrogenation. Single-atom Ru on amorphous porous ultrathin TiO2 nanosheets (Ru1/a-TiO2) is constructed, in which Ru is more positively charged than that in the crystalline counterpart (Ru1/c-TiO2). Moreover, in the nitro/vinyl selective hydrogenation process, Ru1/a-TiO2 shows superior nitro selectivity, opposite to the vinyl selectivity of Ru1/c-TiO2. Density functional theory calculations for single-atom Ru of different charge states show that the reactant adsorption configuration could be inverted in the amorphous TiO2, accounting for the chemo-recognition behavior controlled by the phase of support.

Improved antifouling properties of PVA hydrogel via an organic semiconductor graphitic carbon nitride catalyzed surface-initiated photo atom transfer radical polymerization.

An innovative g-C3N4 catalyzed surface-initiated photo atom transfer radical polymerization (SI-photoATRP) has been developed to construct MEDSAH zwitterionic polymer brushes on PVA hydrogel surface. g-C3N4 catalyzed SI-photoATRP is temporal and spatial control. As a heterogeneous reaction system, it can solve the catalyst residues problem. After grafting with MEDSAH, surface chemical composition and morphology of PVA-g-pMEDSAH hydrogel confirmed that MEDSAH was successfully grafted onto PVA hydrogel. Thermal property of PVA-g-pMEDSAH hydrogel decreased and hydrophilicity increased. No statistically significant differences between PVA and PVA-g-pMEDSAH were observed on mechanical properties. Cytotoxicity in vitro of PVA-g-pMEDSAH hydrogel could be considered as no cytotoxicity for L929 and NDHF cells. The antifouling properties of PVA-g-pMEDSAH hydrogel were significantly improved due to the enhancement of the surface hydration and steric repulsion effects caused by pMEDSAH polymer brushes. In addition, g-C3N4 is easier to modify to enhance the photocatalyst property. Thus, the heterogeneous reaction system of g-C3N4 catalyzed SI-photoATRP has huge potential applied in biomaterials surface modification.

Adipose mesenchymal stem cell transplantation alleviates spinal cord injury-induced neuroinflammation partly by suppressing the Jagged1/Notch pathway.

BACKGROUND: The therapeutic effects of adipose-derived mesenchymal stem cell (ADSC) transplantation have been demonstrated in several models of central nervous system (CNS) injury and are thought to involve the modulation of the inflammatory response. However, the exact underlying molecular mechanism is poorly understood. Activation of the Jagged1/Notch signaling pathway is thought to involve inflammatory and gliotic events in the CNS. Here, we elucidated the effect of ADSC transplantation on the inflammatory reaction after spinal cord injury (SCI) and the potential mechanism mediated by Jagged1/Notch signaling pathway suppression. METHODS: To evaluate the therapeutic effects of ADSC treatment and the potential inhibitory effects of ADSCs on Notch signaling, mice were subjected to contusion SCI, and GFP-labeled ADSCs were injected into the lesion site immediately after the injury. Locomotor function, spinal cord tissue morphology, and the levels of Notch-related proteins and proinflammatory transcripts were compared between groups. To validate the hypothesis that the therapeutic effects of ADSCs are partly due to Notch1 signaling inhibition, a Jagged1 small interfering RNA (siRNA) was injected into the spinal cord to knock down Jagged1/Notch signaling. Neuronal staining and analyses of microglia/macrophage activation and signaling pathways were performed. RESULTS: We demonstrated that ADSCs survived in the injured spinal cord for at least 28 days without differentiating into glial or neuronal elements. ADSC treatment resulted in significant downregulation of proinflammatory mediator expression and reduced ionized calcium-binding adapter molecule 1 (IBA1) and ED-1 staining in the injured spinal cord, eventually improving functional recovery. The augmentation of the Jagged1/Notch signaling pathway after SCI was suppressed by ADSC transplantation. The inhibition of the Jagged1/Notch signaling pathway by Jagged1 siRNA resulted in decreases in SCI-induced proinflammatory cytokines and the activation of microglia and an increase in the survival of neurons. Furthermore, Jagged1 knockdown suppressed the phosphorylation of JAK/STAT3 in astrocytes following SCI. CONCLUSION: The results of this study demonstrated that the therapeutic effects of ADSCs in SCI mice were partly due to Jagged1/Notch signaling pathway inhibition and a subsequent reduction in JAK/STAT3 phosphorylation in astrocytes.

[Multi-spectroscopy applied to study blue gel pen inks].

Multi-spectroscopy, such as FTIR, dispersive Raman spectroscopy and UV-Vis, was applied to characterize the blue gel pen inks on paper at the time in the present study. Twenty eight collected blue gel pens with different brands and serials were separated into four different classes by different absorptions or Raman shift. Composition changing of blue gel pen inks on paper during artificial ageing was studied via TD-MS as well. The advantage and disadvantage of this spectroscopy used in analyzing and identifying blue gel pen inks on paper, and the potential application in the research on relative and absolute ageing of documents were discussed.

Pullout strength of reinserted pedicle screws using the previous entry point and trajectory.

PURPOSE: This study compared the biomechanics of reinserted pedicle screws using the previous entry point and trajectory with those of correctly inserted pedicle screws. METHODS: The study used 18 lumbar vertebrae (L1-6) from three fresh calf spines to insert 6.5 × 40-mm pedicle screws. A control screw was inserted correctly along the axis of one pedicle, while an experimental screw was reinserted completely using the previous entry point and trajectory in the other pedicle. The experimental screw was removed after being completely inserted in group A and after 80% of the total trajectory inserted in group B. And the experimental screw was removed after 60% of the total trajectory was reached in group C. The biomechanical values of the pedicle screws were measured. RESULTS: There were no significant differences in pedicle screw axial pullout strength between reinserted screws and correct screws in the 3 groups (PA = 0.463, PB = 0.753, PC = 0.753). Stiffness measurement increased for the reinserted screw compared with that of the control screw. Fracturing was observed between the vertebral body and pedicle. CONCLUSION: Theoretically, a surgeon can remove the pedicle screw when necessary, inspect the trajectory, and reinsert the screw using the previous entry point and trajectory.

Purification and preliminary crystallographic analysis of a Penicillium expansum lipase.

PF898 is a strain of Penicillium expansum optimized for the high level production of Penicillium expansum lipase (PEL). This PEL is unique compared with other lipases in several aspects, For example, the PEL shows low sequence identities (<30%) to all other known lipases, and high percentage of hydrophobic residues in the N-terminal region. The PEL was purified to homogeneity and shown to be 28 kDa by SDS-PAGE. Crystals suitable for X-ray diffraction analysis were obtained by the sitting-drop method of vapor diffusion with ammonia sulfate as the precipitating agent at 298 K. The crystals have tetragonal lattice and unit-cell parameters of a=b=88.09 A, c=126.54 A. Diffraction data were collected to a resolution of 2.08 A on an in-house rotating-anode generator.