Mixed-Metal MOF-74 Templated Catalysts for Efficient Carbon Dioxide Capture and Methanation

The vast chemical and structural tunability of metal–organic frameworks (MOFs) are beginning to be harnessed as functional supports for catalytic nanoparticles spanning a range of applications. However, a lack of straightforward methods for producing nanoparticle-encapsulated MOFs as efficient heterogeneous catalysts limits their usage. Herein, a mixed-metal MOF, NiMg-MOF-74, is utilized as a template to disperse small Ni nanoclusters throughout the parent MOF. By exploiting the difference in Ni O and Mg O coordination bond strength, Ni²⁺ is selectively reduced to form highly dispersed Ni nanoclusters constrained by the parent MOF pore diameter, while Mg²⁺ remains coordinated in the framework. By varying the ratio of Ni to Mg in the parent MOF, accessible surface area and crystallinity can be tuned upon thermal treatment, influencing CO₂ adsorption capacity and hydrogenation selectivity. The resulting Ni nanoclusters prove to be an active catalyst for CO₂ methanation and are examined using extended X-ray absorption fine structure and X-ray photoelectron spectroscopy. By preserving a segment of the Mg²⁺-containing MOF framework, the composite system retains a portion of its CO₂ adsorption capacity while continuing to deliver catalytic activity. The approach is thus critical for designing materials that can bridge the gap between carbon capture and CO₂ utilization.     

CD46 (membrane cofactor protein of complement, measles virus receptor): structural and functional divergence among species (review)

OBJECT: In this retrospective study, the authors analyzed the frequency, anatomical distribution, and appearance of traumatic brain lesions in 42 patients in a posttraumatic persistent vegetative state. METHODS: Cerebral magnetic resonance (MR) imaging was used to detect the number of lesions, which ranged from as few as five to as many as 19, with a mean of 11 lesions. In all 42 cases there was evidence on MR imaging of diffuse axonal injury, and injury to the corpus callosum was detected in all patients. The second most common area of diffuse axonal injury involved the dorsolateral aspect of the rostral brainstem (74% of patients). In addition, 65% of these patients exhibited white matter injury in the corona radiata and the frontal and temporal lobes. Lesions to the basal ganglia or thalamus were seen in 52% and 40% of patients, respectively. Magnetic resonance imaging showed some evidence of cortical contusion in 48% of patients in this study; the frontal and temporal lobes were most frequently involved. Injury to the parahippocampal gyrus was detected in 45% of patients; in this subgroup there was an 80% incidence of contralateral peduncular lesions in the midbrain. The most common pattern of injury (74% in this series) was the combination of focal lesions of the corpus callosum and the dorsolateral brainstem. In patients with no evidence of diffuse axonal injury in the upper brainstem (26% in this series), callosal lesions were most often associated with basal ganglia lesions. Lesions of the corona radiata and lobar white matter were equally distributed in patients with or without dorsolateral brainstem injury. Moreover, cortical contusions and thalamic, parahippocampal, and cerebral peduncular lesions were also similarly distributed in both groups. CONCLUSIONS: The data indicate that diffuse axonal injury may be the major form of primary brain damage in the posttraumatic persistent vegetative state. In addition, the authors demonstrated in this study that MR imaging, in conjunction with a precise clinical correlation, may provide useful supportive information for the accurate diagnosis of a persistent vegetative state after traumatic brain injury.     

The Clausius inequality corrected for heat transfer involving radiation

The objective of this paper is to prove that the Clausius inequality must be re-stated to have general applicability for heat transfer involving radiative fluxes. The integrand (đQ/T) of the Clausius expression applies to heat conduction and convection, but does not hold for most radiative transfer scenarios, with the exception of reversible infinitesimal net blackbody radiation transfer. In other cases involving radiative transfer, the equality holds for a cycle even though irreversible heat addition by radiative transfer occurs. This is without the erroneous presumption of entropy destruction anywhere in the cycle. Thus, the Clausius inequality indicates reversibility for a cycle that includes an irreversible process. Further, in some radiative cases the quantity đQ/T, where T is the boundary temperature, is not the entropy transfer at the system boundary, and in fact, primarily represents entropy production within the system. It is also clear that in another case considered, the quantity đQ/T had no physical meaning whatsoever. Consequently, the Clausius expression has been re-stated so that it is applicable to cycles with processes involving any form of heat transfer. A new integrand (đQ_cc/T + đS_Net,Rad) is presented, allowing the Clausius inequality to generally apply to all heat transfer scenarios. The work in this paper emphasizes the need to re-state other fundamental equations allowing applicability to all heat transfer processes, and draws attention to the unique character of radiative entropy calculations.     

Effect of process distillation on mutagenicity and cell-transformation activity of solvent-refined,coal-derived liquids

Blended SRC-II process streams, representing a full boiling range distillate material, were fractionally distilled into non-overlapping 50 °F cuts with boiling points between 300 and 850 °F. Another set of 18 distillate cuts were obtained with boiling points ranging between 138 and 1055 °F. Distillate cuts were assayed for mutagenic activity using the histidine reversion assay with Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, as well as for mammalian-cell transformation activity in the Syrian hamster embryo test, and DNA damage in the prophage induction assay. Samples were also separated into chemical class fractions by alumina column chromatography and analysed by high resolution gas chromatography so that the chemical composition of the cuts could be related to their relative activity in the different assays. In the mammalian cell transformation and microbial mutagenicity assays, significant activity was found almost exclusively in distillate cuts with components boiling > 700 °F, with the highest activity in the transformation assay observed for cuts > 800 °F. All of the distillate cuts showed increased levels of DNA damage as expressed by lambda prophage induction in Escherichia coli 8177. However, the greatest activity was associated with distillate cuts with boiling points in the 800 °F + range. Chemical analysis of the 50 °F distillate cuts showed a variety of polycyclic aromatic hydrocarbons (PAH) and amino-PAH compounds to be present in the distillate cuts boiling > 700 °F and essentially absent from cuts boiling < 700 °F. The sample set of non-overlapping (50 °F) cuts were reblended according to the proportions of each cut found in the original blend material. These reblended composites were then assayed to compare their activity with that predicted from the activities of the component distillate cuts. The reblending experiments indicated the microbial mutagenicity response was essentially additive. Mammalian cell transformation activities were non-additive, indicating a compositional effect on the expression of transforming agents in the complex mixture.     

Entities,identities, identifiers and credentials — what does it all mean?

This paper looks at the concepts of entities, identities, identifiers and credentials, their definitions, and how they combine to authenticate an identity to an account, or function, within a service. Credentials can be divided into several different types on the basis of their use, origin and characteristics. In particular, types such as composite, dynamic and derived credentials will be considered, and their applicability within an identity management system. Each credential must be managed through its entire life cycle from initial registration, general use and suspension, to deletion. The notion of public (i.e. freely distributable) and private (i.e. known only to you) aspects of a credential is explored. The bindings, by trusted third parties, of identifiers and public credentials into permits and instruments of proof is explained along with the convenience, but greater exposure, of local information. Several scenarios are analysed in terms of how different types of credentials are employed during the authentication process.     

Ni catalyst promotion of a Cis-selective Pd catalyst for canola oil hydrogenation

A Ni catalyst was added to a cis-selective Pd catalyst in an attempt to further improve the Pd catalyst's cis-selectivity and activity for canola oil hydrogenation. The system was tested under reaction conditions known to be suitable for cis-selective hydrogenation with the Pd catalyst (50 ppm Pd, 70 °C, and 5.2 MPa). Although inactive on its own under these conditions, the addition of 100 ppm Ni increased the hydrogenation activity (from 2.12 to 2.49 10⁻² min⁻¹). Further addition of Ni up to 1000 ppm resulted in no further improvements in activity. The trans isomer contents of the oils hydrogenated with Pd and the Pd/Ni systems were similar. The level of conjugated dienes decreased rapidly during hydrogenation with both Pd alone and with the Pd/Ni combination and no changes in conjugation were detected in the presence of the Ni catalyst alone. The increased activity of the Pd/Ni system over Pd alone was attributed to adsorption of catalyst poisons from the oil by Ni.     

Prevention and Mitigation Strategies to Address Recent Brittle Fractures in Steel Bridges

Brittle fracture results in unplanned loss of service, very costly repairs, concern regarding the future safety of the structure, and potential loss of life. These types of failures are most critical when there is no evidence of fatigue cracking leading up to the fracture and the fracture origin is concealed from view. Hence, the failure occurs without warning and the details are, essentially, noninspectable. In these cases, it appears desirable to take a proactive approach and introduce preventative retrofits to reduce the potential for future crack development. These efforts will help ensure that the likelihood of unexpected fractures is minimized. This paper examines the behavior of two bridge structures in which brittle fractures have developed in recent times, discusses the causes of the failures, and offers suggested design strategies for prevention and retrofit mitigation techniques. In situations where considerable uncertainty exists in the prediction of accumulated damage or in the ability to reliably inspect critical details, preemptive retrofit strategies appear to be highly desirable.     

Renal gunshot wounds: methods of salvage and reconstruction

Over the past 14 years, 2079 patients have been seen at our institution with renal trauma. Of these, 84 sustained gunshot wounds (81 unilateral, 3 bilateral; a total of 87 renal units). We evaluated this group to characterize the nature of their injuries and establish a methodology for renal salvage and reconstruction. Preoperative radiographic staging was performed with excretory urography (IVP) or computed tomographic (CT) scanning. The injuries were classified into five categories: 16 contusions (18.4%), 12 minor lacerations (13.8%), 44 major lacerations (50.5%), six vascular injuries (6.9%), and nine combination laceration and vascular injury (10.3%). Most patients had multiple organ injuries, with 79 requiring associated surgical procedures (94%). The mean injury Severity Score (ISS) was 26.7 (range, 4-59). Based on radiographic and clinical staging criteria, 69 renal injuries were surgically explored (79.3%), and 12 patients underwent nephrectomy (13.8%). Forty-six renal units were reconstructed (66.6%) by various methods, including renorrhaphy, omental pedical flaps, mesh or peritoneal patch grafts, partial nephrectomy, and vascular repair. Overall, 75 renal units were salvaged (86.2%). Early renal vascular control was achieved in all patients who underwent renal exploration. Follow-up functional studies were done in 24 (28.5%): none had delayed nephrectomy or postinjury hypertension. Overall, 79 patients survived (94%); however, mortality was not related to renal injury. These findings suggest that aggressive radiographic staging coupled with early vascular control and careful selection of reconstructive techniques can ensure a high renal salvage rate in patients with renal gunshot injuries.