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Increasing the thickness of the electrodes is considered the primary strategy to elevate battery energy density. However, as the thickness increases, rate performance, cycling performance, and mechanical stability are affected due to the sluggish ion transfer kinetics and compromised structural integrity. Inspired by the natural hierarchical porous structure of trees, electrodes with bioinspired architecture are fabricated to address these challenges. Specifically, electrodes with aligned columns consist of tree-inspired vertical channels, and hierarchical pores are constructed by screen printing and ice-templating, imparting enhanced electrochemical and mechanical performance. Employing an aqueous-based binder, the LiNi0.8Mn0.1Co0.1O2 cathode achieves a high areal energy density of 15.1 mWh cm-2 at a rate of 1C at mass loading of 26.0 mg cm-2, benefitting from the multiscale pores that elevated charge transfer kinetics in the thick electrode. The electrodes demonstrate capacity retention of 90% at the 100th cycle at a high current density of 5.2 mA cm-2. To understand the mechanisms that promote electrode performance, simplified electro-chemo-mechanical models are developed, the drying process and the charge-discharge process are simulated. The simulation results suggested that the improved performance of the designed electrode benefits from the lower ohmic overpotential and less strain gradient and stress concentration due to the hierarchical porous architecture.
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The introduction of noble metal into spinel structure is an effective strategy to develop efficient oxygen evolution/reduction reaction (OER/ORR) catalysts. Herein, surface Cooct is substituted by Ruoct in Rux-Mn0.5Co2.5-xO4/NCNTs by ion-exchange, where presence of RuoctâOâCooct unit facilitates electron transfer. This strong electron coupling effect leads downward shift in d-band center and a narrowing of d-p bandgap. The increased charge density of Cooct bridged with Ruoct dioxygen optimizes adsorption of oxygen intermediates (*OH) and occupation of electrons in eg-orbital octahedral. The measured ORR/OER voltage difference is only 0.71 V. The peak power density of assembled zinc-air battery reaches 148.8 mW h cm-2, and energy density at 100 mA cm-2 reaches 813.6 mA h gZn -1, approaching a theoretical value of 820 mA h gZn -1. The catalyst demonstrates stable operation for over 500 h at 10 mA cm-2 and over 200 h at 50 mA cm-2. This work provides new insights to guide fabrication of advanced oxygen electrocatalysts.
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Prussian blue analogues (PBA) are a large family of functional materials with diverse applications such as in electrochemical fields. However, their use in the emerging two-electron oxygen reduction reaction for clean production of hydrogen peroxide (H2O2) is lagging. Herein, a general solvent exchange induced reconstruction strategy is demonstrated, through which an abnormal NiNi-PBA superstructure is synthesized as a high-performance electrocatalyst for H2O2 generation. The resultant NiNi-PBA superstructure has a stoichiometric composition with saturated lattice water, and a leaf-like morphology composed of interconnected small-size nanosheets with identical orientation and predominate {210} side surface exposure. Our studies show that the Ni-N centers on {210} facets are the active sites, and the saturated lattice H2O favors a six-coordinated environment that results in high selectivity. The "perfect" structure including stoichiometric composition and ideal facet exposure leads to a high selectivity of ~100 % and H2O2 yield of 5.7â mol g-1 h-1, superior to the reported MOF-based electrocatalysts and most other electrocatalysts.
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3D electron diffraction (3D ED) has shown great potential in crystal structure determination in materials, small organic molecules, and macromolecules. In this work, an automated, low-dose and low-bias 3D ED protocol has been implemented to identify six phases from a multiple-phase melt-crystallisation product of an active pharmaceutical ingredient, griseofulvin (GSF). Batch data collection under low-dose conditions using a widely available commercial software was combined with automated data analysis to collect and process over 230 datasets in three days. Accurate unit cell parameters obtained from 3D ED data allowed direct phase identification of GSF Forms III, I and the known GSF inclusion complex (IC) with polyethylene glycol (PEG) (GSF-PEG IC-I), as well as three minor phases, namely GSF Forms II, V and an elusive new phase, GSF-PEG IC-II. Their structures were then directly determined by 3D ED. Furthermore, we reveal how the stabilities of the two GSF-PEG IC polymorphs are closely related to their crystal structures. These results demonstrate the power of automated 3D ED for accurate phase identification and direct structure determination of complex, beam-sensitive crystallisation products, which is significant for drug development where solid form screening is crucial for the overall efficacy of the drug product.
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Elétrons , Polímeros , Polímeros/química , Griseofulvina/química , Polietilenoglicóis/química , Cristalização/métodosRESUMO
BACKGROUND: Noncommunicable diseases (NCDs) and mental health conditions represent a growing proportion of disease burden in low- and middle-income countries (LMICs). While past efforts have identified interventions to be delivered across health system levels to address this burden, the challenge remains of how to deliver heterogenous interventions in resource-constrained settings. One possible solution is the Integration of interventions within existing care delivery models. This study reviews and summarizes published literature on models of integrated NCD and mental health care in LMICs. METHODS: We searched Pubmed, African Index Medicus and reference lists to conduct a scoping review of studies describing an integrated model of NCD or neuropsychiatric conditions (NPs) implemented in a LMIC. Conditions of interest were grouped into common and severe NCDs and NPs. We identified domains of interest and types of service integration, conducting a narrative synthesis of study types. Studies were screened and characteristics were extracted for all relevant studies. Results are reported using PRISMA-ScR. RESULTS: Our search yielded 5004 studies, we included 219 models of integration from 188 studies. Most studies were conducted in middle-income countries, with the majority in sub-Saharan Africa. Health services were offered across all health system levels, with most models implemented at health centers. Common NCDs (including type 2 diabetes and hypertension) were most frequently addressed by these models, followed by common NPs (including depression and anxiety). Conditions and/or services were often integrated into existing primary healthcare, HIV, maternal and child health programs. Services provided for conditions of interest varied and frequency of these services differed across health system levels. Many models demonstrated decentralization of services to lower health system levels, and task shifting to lower cadre providers. CONCLUSIONS: While integrated service design is a promising method to achieve ambitious global goals, little is known about what works, when, and why. This review characterizing care integration programs is an initial step toward developing a structured study of care integration.
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Diabetes Mellitus Tipo 2 , Doenças não Transmissíveis , Humanos , Atenção à Saúde/métodos , Países em Desenvolvimento , Saúde Mental , Doenças não Transmissíveis/epidemiologia , Doenças não Transmissíveis/terapiaRESUMO
Conducting polymers with high theoretical capacitance and deformability are among the optimal candidates for compressible supercapacitor electrode materials. However, achieving both mechanical and electrochemical stabilities in a single electrode remains a great challenge. To address this issue, the "Polymer Chainmail" is proposed with reversible deformation capability and enhances stability because of the steric hindrance and charge compensation effect of doped anions. As a proof of concept, four common anions are selected as dopants for Poly(3,4-ethylenedioxythiophene) (PEDOT), and their effects on the adsorption and diffusion of H+ on PEDOT are verified using density functional theory calculations. Owing to the film formation effect, the PF 6 - ${{\rm{PF}}_6^- }$ doped PEDOT/nitrogen-doped carbon foam exhibits good mechanical properties. Furthermore, the composite demonstrates excellent rate performance and stability due to suitable anion doping. This finding provides new insights into the preparation of electrochemically stable conductive polymer-based compressible electrode materials.
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In the study of framework materials, probing interactions between frameworks and organic molecules is one of the most important tasks, which offers us a fundamental understanding of host-guest interactions in gas sorption, separation, catalysis, and framework structure formation. Single-crystal X-ray diffraction (SCXRD) is a conventional method to locate organic species and study such interactions. However, SCXRD demands large crystals whose quality is often vulnerable to, e.g., cracking on the crystals by introducing organic molecules, and this is a major challenge to use SCXRD for structural analysis. With the development of three-dimensional electron diffraction (3D ED), single-crystal structural analysis can be performed on very tiny crystals with sizes on the nanometer scale. Here, we analyze two framework materials, SU-8 and SU-68, with organic molecules inside their inorganic crystal structures. By applying 3D ED, with fast data collection and an ultralow electron dose (0.8-2.6 e- Å-2), we demonstrate for the first time that each nonhydrogen atom from the organic molecules can be ab initio located from structure solution, and they are shown as distinct and well-separated peaks in the difference electrostatic potential maps showing high accuracy and reliability. As a result, two different spatial configurations are identified for the same guest molecule in SU-8. We find that the organic molecules interact with the framework through strong hydrogen bonding, which is the key to immobilizing them at well-defined positions. In addition, we demonstrate that host-guest systems can be studied at room temperature. Providing high accuracy and reliability, we believe that 3D ED can be used as a powerful tool to study host-guest interactions, especially for nanocrystals.
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Chemoresistance is a major obstacle to the treatment of triple-negative breast cancer (TNBC), which has a poor prognosis. Increasing evidence has demonstrated the essential role of cancer stem cells (CSCs) in the process of TNBC chemoresistance. However, the underlying mechanism remains unclear. In the present study, we report that block of proliferation 1 (BOP1) serves as a key regulator of chemoresistance in TNBC. BOP1 expression was significantly upregulated in chemoresistant TNBC tissues, and high expression of BOP1 correlated with shorter overall survival and relapse-free survival in patients with TNBC. BOP1 overexpression promoted, while BOP1 downregulation inhibited the drug resistance and CSC-like phenotype of TNBC cells in vitro and in vivo. Moreover, BOP1 activated Wnt/ß-catenin signaling by increasing the recruitment of cyclic AMP response element-binding protein (CBP) to ß-catenin, enhancing CBP-mediated acetylation of ß-catenin, and increasing the transcription of downstream stemness-related genes CD133 and ALDH1A1. Notably, treating with the ß-catenin/CBP inhibitor PRI-724 induced an enhancement of chemotherapeutic response of paclitaxel in BOP1-overexpressing TNBC cells. These findings indicate that BOP1 is involved in chemoresistance development and might serve as a prognostic marker and therapeutic target in TNBC. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Resistencia a Medicamentos Antineoplásicos/fisiologia , Regulação Neoplásica da Expressão Gênica/fisiologia , Proteínas de Ligação a RNA/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Acetilação , Animais , Proteína de Ligação a CREB/metabolismo , Feminino , Xenoenxertos , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Neoplasias de Mama Triplo Negativas/metabolismo , Via de Sinalização Wnt/fisiologiaRESUMO
OBJECTIVE: The aim of this retrospective analysis was to explore whether an elevated ALT level before pregnancy is associated with a reduction in live birth rate after IVF-FET. DESIGN: Retrospective observational study. SETTING: Shiyan People's Hospital, China between January 2019 and December 2019. PATIENTS: Women aged ≤ 40 years. INTERVENTION(S): Freeze-thawed embryo transfer (FET). MAIN OUTCOME MEASURE(S): The live birth rate, which was defined as the delivery of a live baby after 24 weeks of gestation. RESULTS: The analysis included 365 FET cycles. There was a significant difference between groups in the live birth rate (p < .05), which was highest for the low ALT tertile and lowest for the high ALT tertile. Multiple regression analysis with adjustment for multiple potential confounders revealed that the odds of live birth were decreased for each one standard deviation increase in ALT (OR = 0.56, 95%CI = 0.42-0.75, p < .0001) and lower for the high ALT tertile than for the low ALT tertile (OR = 0.38, 95%CI = 0.19-0.75, p = .0055). Smooth curve fitting showed an inverse relationship between ALT and live birth rate. CONCLUSION: Our findings indicate that relatively small elevations in baseline serum ALT level can have a clinically relevant impact on the success of FET.
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Coeficiente de Natalidade , Transferência Embrionária , Gravidez , Humanos , Feminino , Taxa de Gravidez , Alanina Transaminase , Estudos Retrospectivos , Nascido Vivo/epidemiologia , Fertilização in vitroRESUMO
BACKGROUND: Arterial hypertension (aHT) is the leading cardiovascular disease (CVD) risk factor in sub-Saharan Africa; it remains, however, underdiagnosed, and undertreated. Community-based care services could potentially expand access to aHT diagnosis and treatment in underserved communities. In this scoping review, we catalogued, described, and appraised community-based care models for aHT in sub-Saharan Africa, considering their acceptability, engagement in care and clinical outcomes. Additionally, we developed a framework to design and describe service delivery models for long-term aHT care. METHODS: We searched relevant references in Embase Elsevier, MEDLINE Ovid, CINAHL EBSCOhost and Scopus. Included studies described models where substantial care occurred outside a formal health facility and reported on acceptability, blood pressure (BP) control, engagement in care, or end-organ damage. We summarized the interventions' characteristics, effectiveness, and evaluated the quality of included studies. Considering the common integrating elements of aHT care services, we conceptualized a general framework to guide the design of service models for aHT. RESULTS: We identified 18,695 records, screened 4,954 and included twelve studies. Four types of aHT care models were identified: services provided at community pharmacies, out-of-facility, household services, and aHT treatment groups. Two studies reported on acceptability, eleven on BP control, ten on engagement in care and one on end-organ damage. Most studies reported significant reductions in BP values and improved access to comprehensive CVDs services through task-sharing. Major reported shortcomings included high attrition rates and their nature as parallel, non-integrated models of care. The overall quality of the studies was low, with high risk of bias, and most of the studies did not include comparisons with routine facility-based care. CONCLUSIONS: The overall quality of available evidence on community-based aHT care is low. Published models of care are very heterogeneous and available evidence is insufficient to recommend or refute further scale up in sub-Sahara Africa. We propose that future projects and studies implementing and assessing community-based models for aHT care are designed and described according to six building blocks: providers, target groups, components, location, time of service delivery, and their use of information systems.
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Serviços de Saúde Comunitária , Hipertensão , África Subsaariana , Instalações de Saúde , Humanos , Hipertensão/diagnóstico , Hipertensão/terapiaRESUMO
Indomethacin is a clinically classical non-steroidal anti-inflammatory drug that has been marketed since 1965. The third polymorph, Form δ, was discovered by both melt and solution crystallization in 1974. δ-indomethacin cannot be cultivated as large single crystals suitable for X-ray crystallography and, therefore, its crystal structure has not yet been determined. Here, we report the structure elucidation of δ-indomethacin by 3D electron diffraction and reveal the truth that melt-crystallized and solution-crystallized δ-indomethacin are in fact two polymorphs with different crystal structures. We propose to keep the solution-crystallized polymorph as Form δ and name the melt-crystallized polymorph as Form θ. Intriguingly, both structures display plastic flexibility based on a slippage mechanism, making indomethacin the first drug to have two plastic polymorphs. This discovery and correction of a 47-year-old misunderstanding signify that 3D electron diffraction has become a powerful tool for polymorphic structural studies.
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Anti-Inflamatórios não Esteroides/química , Indometacina/química , Cristalografia por Raios X , Modelos Moleculares , Estrutura MolecularRESUMO
BACKGROUND: Non-communicable diseases (NCDs) are a growing burden which affects every part of the world, including developing countries. Chronic kidney disease (CKD) has varied etiology which can result from or complicate other NCDs such as diabetes and cardiovascular diseases. The growing prevalence of NCDs coupled with the increasing age in most developing countries, has seen a marked increase of CKD in these settings. CKD has been described as "the most neglected NCD" and greatly affects the quality of life of patients. It also places a huge economic burden on societies. However, few epidemiological data exist, particularly in sub-Saharan Africa. Assessment of the prevalence of albuminuria as a marker of kidney damage and CKD progression and its main risk factors was thus needed in Rwanda. METHODS: This study analyzed data collected during the first STEPwise approach to NCD risk factor Surveillance (STEPS) survey in Rwanda, conducted from 2012 to 2013, to assess the prevalence of albuminuria. A multistage cluster sampling allowed to select a representative sample of the general population. Furthermore, descriptive, as well as univariable analyses and multiple logistic regression were performed to respond to the research question. RESULTS: This survey brought a representative sample of 6,998 participants, among which 4,384 (62.65%) were female. Median age was 33 years (interquartile range, IQR 26-44), and over three quarters (78.45%) lived in rural areas. The albuminuria prevalence was 105.9 per 1,000 population. Overall, semi-urban and urban residency were associated with lower odds of CKD (odds ratio, OR 0.36, CI 0.23-0.56, p<0.001 and OR 0.34, CI 0.23-0.50, p<0.001, respectively) than rural status. Being married or living with a partner had higher odds (OR 1.44 (CI 1.03-2.02, p=0.031) and OR 1.62 (CI 1.06-2.48, p=0.026), respectively) of CKD than being single. Odds of positive albuminuria were also greater among participants living with human immunodeficiency virus (HIV) (OR 1.64, CI 1.09- 2.47, p=0.018). Gender, age group, smoking status and vegetable consumption, body mass index (BMI) and hypertension were not associated with albuminuria. CONCLUSION: The albuminuria prevalence was estimated at 105.9 per 1,000 in Rwanda. Rural residence, partnered status and HIV positivity were identified as main risk factors for albuminuria. Increased early screening of albuminuria to prevent CKD among high-risk groups, especially HIV patients, is therefore recommended.
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Albuminúria/epidemiologia , Insuficiência Renal Crônica/epidemiologia , Adolescente , Adulto , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Ruanda/epidemiologia , Autorrelato , Adulto JovemRESUMO
A new layered mesoporous Zr-MOF of composition [Zr30O20(OH)26(OAc)18L18] was synthesized by employing 5-acetamidoisophthalic acid (H2L) using acetic acid as the solvent. The new MOF, denoted as CAU-45, exhibits a honeycomb structure of stacked layers which comprise both hexa- and dodecanucelar zirconium clusters. Its structure was solved from submicrometer-sized crystals by continuous rotation electron diffraction (cRED). Liquid phase exfoliation and size selection were successfully performed on the material.
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The oxygen reduction reaction (ORR) is central in carbon-neutral energy devices. While platinum group materials have shown high activities for ORR, their practical uses are hampered by concerns over deactivation, slow kinetics, exorbitant cost, and scarce nature reserve. The low cost yet high tunability of metal-organic frameworks (MOFs) provide a unique platform for tailoring their characteristic properties as new electrocatalysts. Herein, we report a new concept of design and present stable Zr-chain-based MOFs as efficient electrocatalysts for ORR. The strategy is based on using Zr-chains to promote high chemical and redox stability and, more importantly, tailor the immobilization and packing of redox active-sites at a density that is ideal to improve the reaction kinetics. The obtained new electrocatalyst, PCN-226, thereby shows high ORR activity. We further demonstrate PCN-226 as a promising electrode material for practical applications in rechargeable Zn-air batteries, with a high peak power density of 133 mW cm-2. Being one of the very few electrocatalytic MOFs for ORR, this work provides a new concept by designing chain-based structures to enrich the diversity of efficient electrocatalysts and MOFs.
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Microcrystal electron diffraction (MicroED) has recently shown to be a promising technique for structure determination in structural biology and pharmaceutical chemistry. Here, we discuss the unique properties of electrons and motivate its use for diffraction experiments. We review the latest developments in MicroED, and illustrate its applications in macromolecular crystallography, fragment screening and structure guided drug discovery. We discuss the perspectives of MicroED in synthetic chemistry and pharmaceutical development. We anticipate that the rapid advances MicroED showcased here will promote further development of electron crystallography and open up new opportunities for drug discovery.
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Elétrons , Preparações Farmacêuticas , Cristalografia por Raios XRESUMO
A new aluminosilicate zeolite, denoted EMM-37, with a 3D small pore channel system, has been synthesized using a diquaternary ammonium molecule as the structure directing agent (SDA) and metakaolin as the aluminum source. The structures of both as-made and calcined forms of EMM-37 were solved and refined using continuous rotation electron diffraction (cRED) data. cRED is a powerful method for the collection of 3D electron diffraction data from submicron- and nanosized crystals, which allows for successful solution and refinement of complex structures in symmetry as low as P1Ì .
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Single-crystal electron diffraction has shown to be powerful for structure determination of nano- and submicron-sized crystals that are too small to be studied by single-crystal X-ray diffraction. However, it has been very challenging to obtain high quality electron diffraction data from beam sensitive crystals such as metal-organic frameworks (MOFs). It is even more difficult to locate guest species in the pores of MOF crystals. Here, we present synthesis of a novel porous cobalt MOF with 1D channels, [Co2 (Ni-H4 TPPP)]â 2 DABCOâ 6 H2 O, (denoted Co-CAU-36; DABCO=1,4-diazabicyclo[2.2.2]octane), and its structure determination using continuous rotation electron diffraction (cRED) data. By combining a fast hybrid electron detector with low sample temperature (96â K), high resolution (0.83-1.00â Å) cRED data could be obtained from eight Co-CAU-36 crystals. Independent structure determinations were conducted using each of the eight cRED datasets. We show that all atoms in the MOF framework could be located. More importantly, we demonstrate for the first time that organic molecules in the pores, which were previously difficult to find, could be located using the cRED data. A comparison of eight independent structure determinations using different datasets shows that structural models differ only on average by 0.03(2)â Å for the framework atoms and 0.10(6) and 0.16(12)â Å for DABCO and water molecules, respectively.
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Guiding surface electromagnetic waves around disorder without disturbing the wave amplitude or phase is in great demand for modern photonic and plasmonic devices, but is fundamentally difficult to realize because light momentum must be conserved in a scattering event. A partial realization has been achieved by exploiting topological electromagnetic surface states, but this approach is limited to narrow-band light transmission and subject to phase disturbances in the presence of disorder. Recent advances in transformation optics apply principles of general relativity to curve the space for light, allowing one to match the momentum and phase of light around any disorder as if that disorder were not there. This feature has been exploited in the development of invisibility cloaks. An ideal invisibility cloak, however, would require the phase velocity of light being guided around the cloaked object to exceed the vacuum speed of light--a feat potentially achievable only over an extremely narrow band. In this work, we theoretically and experimentally show that the bottlenecks encountered in previous studies can be overcome. We introduce a class of cloaks capable of remarkable broadband surface electromagnetic waves guidance around ultrasharp corners and bumps with no perceptible changes in amplitude and phase. These cloaks consist of specifically designed nonmagnetic metamaterials and achieve nearly ideal transmission efficiency over a broadband frequency range from 0(+) to 6 GHz. This work provides strong support for the application of transformation optics to plasmonic circuits and could pave the way toward high-performance, large-scale integrated photonic circuits.
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A bismuth-based metal-organic framework (MOF), [Bi(BTC)(H2O)]·2H2O·MeOH denoted CAU-17, was synthesized and found to have an exceptionally complicated structure with helical Bi-O rods cross-linked by 1,3,5-benzenetricarboxylate (BTC(3-)) ligands. Five crystallographically independent 1D channels including two hexagonal channels, two rectangular channels, and one triangular channel have accessible diameters of 9.6, 9.6, 3.6, 3.6, and 3.4 Å, respectively. The structure is further complicated by twinning. Rod-incorporated MOF structures typically have underlying nets with only one unique node and three or four unique edges. In contrast, topological analysis of CAU-17 revealed unprecedented complexity for a MOF structure with 54 unique nodes and 135 edges. The complexity originates from the rod packing and the rods themselves, which are related to aperiodic helices.