Beyond the Artifact: Unfolding Medieval, Algorithmic, and Unruly Lives of Maps

Found on the walls of ancient caves in northern France, the earliest known maps do not depict the earth but the brightest stars of the milky way. Although we know little about the people who painted these maps, we know that they, like us, looked for answers and meaning. Mapping as material testimony of this desire signals a basic function of human placemaking. Discarding the biographical shallowness of cartography, this paper investigates how maps might assume social agency. Since spaces are (socially) constructed not only of sight but also of memories, affect, or tactile experiences, I investigate how maps enter spatiotemporal relationships and become agents of social critique by asking: When do maps exceed their role as material artifacts by interfacing with mental geographies of individuals or societal structures? Unfolding the social lives of maps, the paper proposes, demonstrates their ability to exceed traditionally assumed utilitarian roles as lifeless transmitters of ‘objective’ facts, instead revealing cartographic assemblages of identity, memory, trauma, and protest

Removal of diclofenac by adsorption process studied in free-base porphyrin Zr-metal organic frameworks (Zr-MOFs)

As the world population continues to grow, there is also a rising concern regarding water pollution since this condition could negatively impact the supply of clean water. One of the most recent concerns is related to the pollution that comes from various pharmaceuticals, in particular non-steroidal anti-inflammatory drugs (NSAIDs) since they have been industrially produced at large scale and can be easily purchased as an over-the-counter medicine. Diclofenac is one of the most popular NSAIDs because of its high-effectiveness, which leads to its excessive consumption. Consequently, its presence in water bodies is also continuously increasing. An adsorption process could then be employed as a highly effective method to address this issue. In comparison to other conventional adsorbents such as activated carbon, the use of metal–organic frameworks (MOFs) as an alternative adsorbent is very attractive since it can offer various advantages such as tailorability and high adsorption capacity. In this study, the performance of three water-stable, free-base porphyrin MOFs assembled using zirconia-based nodes, namely MOF-525, MOF-545, and NU-902, for diclofenac adsorption was thoroughly investigated. Interestingly, although all three free-base porphyrin MOFs are assembled using the same building block and have a similar specific surface area (based on the experimental argon physisorption and calculation based on non-localized density functional theory), their diclofenac adsorption capacity is substantially different from one another. It is found that the highest diclofenac adsorption capacity is shown by MOF-525, which has maximum capacity around 792 mg g$^{−1}$. This is then followed by MOF-545 and NU-902 that have adsorption capacities around 591 and 486 mg g$^{−1}$, respectively. Some possible adsorption mechanisms are then thoroughly discussed that might contribute to this phenomenon. Lastly, their performance is also compared with other MOFs that are also studied for this purpose to show their performance superiority not only in terms of adsorption capacity but also their affinity towards the diclofenac molecule, which might be useful as an adsorption performance indicator in the real condition where the contaminant concentration is considerably low

Chemical Reactions at Isolated Single-Sites Inside Metal–Organic Frameworks

Isolated, coordinatively unsaturated metal sites within metal–organic framework (MOF) materials feature interesting chemical properties and offer applications as single-site catalysts. Here, we report on the recent progress in providing fundamental insight into chemical reactions occurring inside MOFs. In addition to the common form, powders, we discuss the potential of MOF thin films (SURMOFs). The combined spectroscopic and modeling approach applied to selected systems demonstrated that the catalytic activity of MOFs can be precisely tuned. A particular interesting case is the so-called defect-engineering, where structural imperfections are created in a controlled fashion. The chemical properties of MOF materials can be further modified by integration and decoration of linkers or loading with guest species, such as metal or metal–oxide nanoparticles or nanoclusters. A particularly interesting aspect of layer-by-layer approaches for the fabrication of MOF thin films is the prospect to realize tandem catalysts

Hierarchical assemblies of molecular frameworks—MOF-on-MOF epitaxial heterostructures

Functional, porous metal-organic frameworks (MOFs) have attracted much attention as a very flexible class of crystalline, porous materials. For more advanced applications that exploit photophysical properties, the fabrication of hierarchical assemblies, including the creation of MOF/MOF heterointerfaces, is important. For the manufacturing of superstructures with length scales well beyond that of the MOF pore size, layer-by-layer (lbl) methods are particularly attractive. These allow the isoreticular approach to be extended to superstructures with micrometer length scales, a range that is not accessible using conventional MOF design. The lbl approach further substantially extends the compositional diversity in MOFs. At the same time, the favorable elastic properties of MOFs allow for heteroepitaxial growth, even in the case of lattice misfits as large as 20%. While the MOF-on-MOF approach to designing multicomponent superstructures with synergistic multifunctionality can also be realized with sophisticated solvothermal synthesis schemes, the lbl (or liquid-phase epitaxy) approach carries substantial advantages, in particular when it comes to the integration of such MOF superstructures into optical or electronic devices. While the structure vertical to the substrate can be adjusted using the lbl method, photolithographic methods can be used for lateral structuring. In this review, we will discuss the lbl liquid-phase epitaxy approach to growing surface-anchored MOF thins films (SURMOFs) as well as other relevant one-pot synthesis methods for constructing such hierarchically designed structures and their emerging applications

Investigation of the reversibility of freeze/thaw stress-induced protein instability using heat cycling as a function of different cryoprotectants

Formulation conditions have a significant influence on the degree of freeze/thaw (FT) stress-induced protein instabilities. Adding cryoprotectants might stabilize the induced FT stress instabilities. However, a simple preservation of protein stability might be insufficient and further methods are necessary. This study aims to evaluate the addition of a heat cycle following FT application as a function of different cryoprotectants with lysozyme as exemplary protein. Sucrose and glycerol were shown to be the most effective cryoprotectants when compared to PEG200 and Tween20. In terms of heat-induced reversibility of aggregates, glycerol showed the best performance followed by sucrose, NaCl and Tween20 systems. The analysis was performed using a novel approach to visualize complex interplays by a clustering and data reduction scheme. In addition, solubility and structural integrity were measured and confirmed the obtained results

Electrostatic design of polar metal–organic framework thin films

In recent years, optical and electronic properties of metal–organic frameworks (MOFs) have increasingly shifted into the focus of interest of the scientific community. Here, we discuss a strategy for conveniently tuning these properties through electrostatic design. More specifically, based on quantum-mechanical simulations, we suggest an approach for creating a gradient of the electrostatic potential within a MOF thin film, exploiting collective electrostatic effects. With a suitable orientation of polar apical linkers, the resulting non-centrosymmetric packing results in an energy staircase of the frontier electronic states reminiscent of the situation in a pin-photodiode. The observed one dimensional gradient of the electrostatic potential causes a closure of the global energy gap and also shifts core-level energies by an amount equaling the size of the original band gap. The realization of such assemblies could be based on so-called pillared layer MOFs fabricated in an oriented fashion on a solid substrate employing layer by layer growth techniques. In this context, the simulations provide guidelines regarding the design of the polar apical linker molecules that would allow the realization of MOF thin films with the (vast majority of the) molecular dipole moments pointing in the same direction