Neutron Vibrational Spectroscopic Study of the Acetylene: Ammonia (1:1) Cocrystal Relevant to Titan, Saturn's Moon.

The surface of Titan, Saturn's icy moon, is believed to be composed of various molecular minerals with a great diversity in structure and composition. Under the surface conditions, 93 K and 1.45 atm, most small molecules solidify and form minerals, including acetylene and ammonia. These two compounds can not only form single-component solids but also a 1:1 binary cocrystal that exhibits intriguing rotor phase behavior. This cocrystal is a putative mineral on Titan and other planetary bodies such as comets. In addition, the structure of the cocrystal is relevant to fundamental science as it can help better understand the emergence of rotor phases. Here, we present a detailed vibrational neutron spectroscopic study supported by a neutron powder diffraction study on the cocrystal and the single-phase solids. The experimentally observed spectral bands were assigned based on theoretical calculations. The established spectra-properties correlations for the cocrystal corroborate the observed properties. To the best of our knowledge, this study presents the first example of the application of neutron vibrational spectroscopy in studying Titan-relevant organic minerals.

Bubbles enable volumetric negative compressibility in metastable elastocapillary systems.

Although coveted in applications, few materials expand when subject to compression or contract under decompression, i.e., exhibit negative compressibility. A key step to achieve such counterintuitive behaviour is the destabilisations of (meta)stable equilibria of the constituents. Here, we propose a simple strategy to obtain negative compressibility exploiting capillary forces both to precompress the elastic material and to release such precompression by a threshold phenomenon - the reversible formation of a bubble in a hydrophobic flexible cavity. We demonstrate that the solid part of such metastable elastocapillary systems displays negative compressibility across different scales: hydrophobic microporous materials, proteins, and millimetre-sized laminae. This concept is applicable to fields such as porous materials, biomolecules, sensors and may be easily extended to create unexpected material susceptibilities.

Mild-Temperature Supercritical Water Confined in Hydrophobic Metal-Organic Frameworks.

Fluids under extreme confinement show characteristics significantly different from those of their bulk counterpart. This work focuses on water confined within the complex cavities of highly hydrophobic metal-organic frameworks (MOFs) at high pressures. A combination of high-pressure intrusion-extrusion experiments with molecular dynamic simulations and synchrotron data reveals that supercritical transition for MOF-confined water takes place at a much lower temperature than in bulk water, ∼250 K below the reference values. This large shifting of the critical temperature (Tc) is attributed to the very large density of confined water vapor in the peculiar geometry and chemistry of the cavities of Cu2tebpz (tebpz = 3,3',5,5'-tetraethyl-4,4'-bipyrazolate) hydrophobic MOF. This is the first time the shift of Tc is investigated for water confined within highly hydrophobic nanoporous materials, which explains why such a large reduction of the critical temperature was never reported before, neither experimentally nor computationally.

Effect of Crystallite Size on the Flexibility and Negative Compressibility of Hydrophobic Metal-Organic Frameworks.

Flexible nanoporous materials are of great interest for applications in many fields such as sensors, catalysis, material separation, and energy storage. Of these, metal-organic frameworks (MOFs) are the most explored thus far. However, tuning their flexibility for a particular application remains challenging. In this work, we explore the effect of the exogenous property of crystallite size on the flexibility of the ZIF-8 MOF. By subjecting hydrophobic ZIF-8 to hydrostatic compression with water, the flexibility of its empty framework and the giant negative compressibility it experiences during water intrusion were recorded via in operando synchrotron irradiation. It was observed that as the crystallite size is reduced to the nanoscale, both flexibility and the negative compressibility of the framework are reduced by ∼25% and ∼15%, respectively. These results pave the way for exogenous tuning of flexibility in MOFs without altering their chemistries.

Balancing climate resilience and adaptation for Caribbean Small Island Developing States (SIDS): Building institutional capacity.

Although the Caribbean's Small Island Developing States (SIDS) minimally contribute to global greenhouse gas emissions, they face disproportionate climate risks and are particularly susceptible to systemic economic threats posed by climate change and subsequent increases in climate variability. Historically, strategic programs and investments have sought to develop more robust and adaptive engineered systems to absorb climate threats. However, such initiatives are limited and under-resourced in the SIDS' context. This article reviews existing climate strategies in the Caribbean and then critically examines current gaps and barriers relating to climate impact knowledge, needs, and implementation. This examination can assist Caribbean SIDS leadership to identify opportunities to transition from a vulnerability-reducing mindset to one of resilience and transformative adaptation to improve long-term economic outlooks, social welfare, and environmental stewardship despite recurring and escalating climate risks. Integr Environ Assess Manag 2023;00:1-19. © 2023 SETAC.

The worsening divergence of biotechnology: the importance of risk culture.

In the last 20 years, the field of biotechnology has made significant progress and attracted substantial investments, leading to different paths of technological modernization among nations. As a result, there is now an international divide in the commercial and intellectual capabilities of biotechnology, and the implications of this divergence are not well understood. This raises important questions about why global actors are motivated to participate in biotechnology modernization, the challenges they face in achieving their goals, and the possible future direction of global biotechnology development. Using the framework of prospect theory, this paper explores the role of risk culture as a fundamental factor contributing to this divergence. It aims to assess the risks and benefits associated with the early adoption of biotechnology and the regulatory frameworks that shape the development and acceptance of biotechnological innovations. By doing so, it provides valuable insights into the future of biotechnology development and its potential impact on the global landscape.

Bimetallic Zeolitic Imidazole Frameworks for Improved Stability and Performance of Intrusion-Extrusion Energy Applications.

Hydrophobic flexible zeolitic imidazole frameworks (ZIFs) represent reference microporous materials in the area of mechanical energy storage, conversion, and dissipation via non-wetting liquid intrusion-extrusion cycle. However, some of them exhibit drawbacks such as lack of stability, high intrusion pressure, or low intrusion volume that make them non-ideal materials to consider as candidates for real applications. In this work, we face these limitations by exploiting the hybrid ZIF concept. Concretely, a bimetallic SOD-like ZIF consisting of Co and Zn ions was synthesized and compared with Co-ZIF (ZIF-67) and Zn-ZIF (ZIF-8) showing for the first time that the hybrid ZIF combines the good stability of ZIF-8 with the higher water intrusion volume of ZIF-67. Moreover, it is shown that the hybrid-ZIF approach can be used to tune the intrusion/extrusion pressure, which is crucial for technological applications.

Adaptive Pore Opening to Form Tailored Adsorption Sites in a Cooperatively Flexible Framework Enables Record Inverse Propane/Propylene Separation.

A proposed low-energy alternative to the separation of alkanes from alkenes by energy-intensive cryogenic distillation is separation by porous adsorbents. Unfortunately, most adsorbents preferentially take up the desired, high-value major component alkene, requiring frequent regeneration. Adsorbents with inverse selectivity for the minor component alkane would enable the direct production of purified, reagent-grade alkene, greatly reducing global energy consumption. However, such materials are exceedingly rare, especially for propane/propylene separation. Here, we report that through adaptive and spontaneous pore size and shape adaptation to optimize an ensemble of weak noncovalent interactions, the structurally responsive metal-organic framework CdIF-13 (sod-Cd(benzimidazolate)2) exhibits inverse selectivity for propane over propylene with record-setting separation performance under industrially relevant temperature, pressure, and mixture conditions. Powder synchrotron X-ray diffraction measurements combined with first-principles calculations yield atomic-scale insight and reveal the induced fit mechanism of adsorbate-specific pore adaptation and ensemble interactions between ligands and adsorbates. Dynamic column breakthrough measurements confirm that CdIF-13 displays selectivity under mixed-component conditions of varying ratios, with a record measured selectivity factor of α ≈ 3 at 95:5 propylene:propane at 298 K and 1 bar. When sequenced with a low-cost rigid adsorbent, we demonstrated the direct purification of propylene under ambient conditions. This combined atomic-level structural characterization and performance testing firmly establishes how cooperatively flexible materials can be capable of unprecedented separation factors.

Mechanism of Water Intrusion into Flexible ZIF-8: Liquid Is Not Vapor.

Zeolitic Imidazolate Frameworks (ZIF) find application in storage and dissipation of mechanical energy. Their distinctive properties linked to their (sub)nanometer size and hydrophobicity allow for water intrusion only under high hydrostatic pressure. Here we focus on the popular ZIF-8 material investigating the intrusion mechanism in its nanoscale cages, which is the key to its rational exploitation in target applications. In this work, we used a joint experimental/theoretical approach combining in operando synchrotron experiments during high-pressure intrusion experiments, molecular dynamics simulations, and stochastic models to reveal that water intrusion into ZIF-8 occurs by a cascade filling of connected cages rather than a condensation process as previously assumed. The reported results allowed us to establish structure/function relations in this prototypical microporous material, representing an important step to devise design rules to synthesize porous media.

"Modest doubt is called the beacon of the wise"-Incorporating uncertainty in risk analysis from Shakespeare to today.

"Modest doubt is call'd the beacon of the wise."-William Shakespeare, Troilus and Cressida. Although the character Hector warns his fellow Trojans with this line not to engage in war against the Greeks, Shakespeare's works are replete with characters who do not incorporate modest doubt, or any consideration of uncertainty, in their risk decisions. Perhaps Shakespeare was simply a keen observer of human nature. Although risk science has developed tremendously over the last five decades (and scientific inquiry over five centuries), the human mind still frequently defaults to conviction about certain beliefs, absent sufficient scientific evidence-which has effects not just on individual lives, but on policy decisions that affect many. This perspective provides background on the Shakespearean quote in its literary and historical context. Then, as this quote is the theme of the 2023 Society for Risk Analysis Annual Meeting, we describe how "modest doubt"-incorporating the notion of uncertainty into risk analysis for individual and policy decisions-is still the "beacon of the wise" today.

Thermal Polymorphism in CsCB11H12.

Thermal polymorphism in the alkali-metal salts incorporating the icosohedral monocarba-hydridoborate anion, CB11H12-, results in intriguing dynamical properties leading to superionic conductivity for the lightest alkali-metal analogues, LiCB11H12 and NaCB11H12. As such, these two have been the focus of most recent CB11H12- related studies, with less attention paid to the heavier alkali-metal salts, such as CsCB11H12. Nonetheless, it is of fundamental importance to compare the nature of the structural arrangements and interactions across the entire alkali-metal series. Thermal polymorphism in CsCB11H12 was investigated using a combination of techniques: X-ray powder diffraction; differential scanning calorimetry; Raman, infrared, and neutron spectroscopies; and ab initio calculations. The unexpected temperature-dependent structural behavior of anhydrous CsCB11H12 can be potentially justified assuming the existence of two polymorphs with similar free energies at room temperature: (i) a previously reported, ordered R3 polymorph stabilized upon drying and transforming first to R3c symmetry near 313 K and then to a similarly packed but disordered I43d polymorph near 353 K and (ii) a disordered Fm3 polymorph that initially appears from the disordered I43d polymorph near 513 K along with another disordered high-temperature P63mc polymorph. Quasielastic neutron scattering results indicate that the CB11H12- anions in the disordered phase at 560 K are undergoing isotropic rotational diffusion, with a jump correlation frequency [1.19(9) × 1011 s-1] in line with those for the lighter-metal analogues.

Defining and analyzing health system resilience in rural jurisdictions.

Rural areas face well known and distinctive health care challenges that can limit their resilience in the face of health emergencies such as the COVID-19 pandemic. These include problems of sparsity and consequent limited health care provisioning; poverty, inequalities, and distinctive economic structures that limit access to health care; and underlying population health risks and inequalities that can increase vulnerability. Nonetheless, not all rural areas face the same problems, and non-rural areas can have challenges. To be useful in influencing policy, a tool to identify more and less resilient areas is necessary. This Commentary reviews key forms of risk and constructs a county-level index of resilience for the United States which helps to identify countries with limited resilience. Further, it argues that health care resilience should be conceptualized in terms of broader regions than counties since health care facilities' referral regions are larger than individual counties; resilience needs to be understood at that level. The index, read at the level of counties and referral regions, can contribute to identification of immediate problems as well as targets for longer term investment and policy response.

Assessment of the COVID-19 infection risk at a workplace through stochastic microexposure modeling.

BACKGROUND: The COVID-19 pandemic has a significant impact on economy. Decisions regarding the reopening of businesses should account for infection risks. OBJECTIVE: This paper describes a novel model for COVID-19 infection risks and policy evaluations. METHODS: The model combines the best principles of the agent-based, microexposure, and probabilistic modeling approaches. It takes into account specifics of a workplace, mask efficiency, and daily routines of employees, but does not require specific inter-agent rules for simulations. Likewise, it does not require knowledge of microscopic disease related parameters. Instead, the risk of infection is aggregated into the probability of infection, which depends on the duration and distance of every contact. The probability of infection at the end of a workday is found using rigorous probabilistic rules. Unlike previous models, this approach requires only a few reference data points for calibration, which are more easily collected via empirical studies. RESULTS: The application of the model is demonstrated for a typical office environment and for a real-world case. CONCLUSION: The proposed model allows for effective risk assessment and policy evaluation when there are large uncertainties about the disease, making it particularly suitable for COVID-19 risk assessments.

Governing biotechnology to provide safety and security and address ethical, legal, and social implications.

The field of biotechnology has produced a wide variety of materials and products which are rapidly entering the commercial marketplace. While many developments promise revolutionary benefits, some of them pose uncertain or largely untested risks and may spur debate, consternation, and outrage from individuals and groups who may be affected by their development and use. In this paper we show that the success of any advanced genetic development and usage requires that the creators establish technical soundness, ensure safety and security, and transparently represent the product's ethical, legal, and social implications (ELSI). We further identify how failures to address ELSI can manifest as significant roadblocks to product acceptance and adoption and advocate for use of the "safety-by-design" governance philosophy. This approach requires addressing risk and ELSI needs early and often in the technology development process to support innovation while providing security and safety for workers, the public, and the broader environment. This paper identifies and evaluates major ELSI challenges and perspectives to suggest a methodology for implementing safety-by-design in a manner consistent with local institutions and politics. We anticipate the need for safety-by-design approach to grow and permeate biotechnology governance structures as the field expands in scientific and technological complexity, increases in public attention and prominence, and further impacts human health and the environment.

Resilience and efficiency for the nanotechnology supply chains underpinning COVID-19 vaccine development.

Nanotechnology facilitated the development and scalable commercialization of many SARS-CoV-2 vaccines. However, the supply chains underpinning vaccine manufacturing have demonstrated brittleness at various stages of development and distribution. Whereas such brittleness leaves the broader pharmacological supply chain vulnerable to significant and unacceptable disruption, strategies for supply chain resilience are being considered across government, academia, and industry. How such resilience is understood and parameterized, however, is contentious. Our review of the nanotechnology supply chain resilience literature, synthesized with the larger supply chain resilience literature, analyzes current trends in implementing and modeling resilience and recommendations for bridging the gap in the lack of quantitative models, consistent definitions, and trade-off analyses for nano supply chains.