Rational Design of Pore Size and Functionality in a Series of Isoreticular Zwitterionic Metal-Organic Frameworks

The isoreticular expansion and functionalization of charged-polarized porosity has been systematically explored by the rational design of 11 isostructural zwitterionic metal-organic frameworks (ZW-MOFs). This extended series of general structural composition {[M3F(L1)3(L2)1.5]·guests}n was prepared by employing the solvothermal reaction of Co and Ni tetrafluoroborates with a binary ligand system composed of zwitterionic pyridinium derivatives and traditional functionalized ditopic carboxylate auxiliary ligands (HL1·Cl = 1-(4-carboxyphenyl)-4,4′-bipyridinium chloride, Hcpb·Cl; or 1-(4-carboxyphenyl-3-hydroxyphenyl)-4,4′-bipyridinium chloride, Hchpb·Cl; and H2L2 = benzene-1,4-dicarboxylic acid, H2bdc; 2-aminobenzene-1,4-dicarboxylic acid, H2abdc; 2,5-dihydroxy-1,4-benzenedicarboxylic acid, H2dhbdc; biphenyl-4,4′-dicarboxylic acid, H2bpdc; or stilbene-4,4′-dicarboxylic acid, H2sdc). Single-crystal structure analyses revealed cubic crystal symmetry (I-43m, a = 31-36 Å) with a 3D pore system of significant void space (73-81%). The pore system features three types of pores being systematically tunable in size ranging from 17.4 to 18.8 Å (pore I), 8.2 to 12.8 Å (pore II), and 4.8 to 10.4 Å (pore III) by the choice of auxiliary ligands. All members of this series have noninterpenetrating structures and exhibit robust architectures, as evidenced by their permanent porosity and high thermal stability (up to 300 °C). The structural integrity and specific surface areas could be systematically optimized using supercritical CO2 exchange methods for framework activation resulting in BET surface areas ranging from 1250 to 2250 m2/g. Most interestingly, as a structural landmark, we found the pore surfaces lined with charge gradients employed by the pyridinium ligands. This key feature results in significant adsorption of carbon dioxide and methane which is attributed to polarization effects. With this contribution we pioneer the reticulation of pyridinium building blocks into extended zwitterionic networks in which specific properties can be targeted

GAMBARAN PENERAPAN PEDOMAN UMUM GIZI SEIMBANG MAHASISWA SEMESTER VI FAKULTAS KESEHATAN MASYARAKAT UNIVERSITAS SAM RATULANGI SELAMA MASA PANDEMI COVID-19

Pada masa pandemi COVID-19 ini WHO telah merekomendasikan menu gizi seimbang yaitu disetiap menu makanan harus mencakup nutrisi lengkap, baik itu makronutrien seperti karbohidrat, protein, lemak, serta mikronutrien dari vitamin dan mineral. Dalam meningkatkan sistem kekebalan tubuh selama masa pandemi COVID-19, kita harus mempertahankan pola makan gizi seimbang, cuci tangan dengan air mengalir dan sabun serta rutin melakukan aktivitas fisik. Penelitian ini bertujuan untuk mengetahui gambaran penerapan pedoman umum gizi seimbang pada mahasiswa semester VI Fakultas Kesehatan Masyarakat Universitas Sam Ratulangi selama masa pandemi COVID-19. Penelitian ini bersifat deskriptif kuantitatif dengan desain cross – sectional dengan jumlah sampel sebanyak 151 orang. Penelitian ini dilakukan di Fakultas Kesehatan Masyarakat Universitas Sam Ratulangi pada bulan Juni – Agustus 2020. Pengumpulan data dilakukan dengan cara menghubungi responden melalui whatsapp kemudian membagikan kuesioner online melalui aplikasi google forms kepada responden dan pengukuran menggunakan skala likert. Hasil penelitian menunjukkan bahwa penerapan pedoman umum gizi seimbang pada mahasiswa semester VI Fakultas Kesehatan Masyarakat Universitas Sam Ratulangi sebagian besar masuk pada kategori cukup yaitu sebanyak 128 orang (84,7%). Adapun yang termasuk dalam kategori kurang yaitu sebanyak 9 orang (6%). Kata Kunci: Pedoman Umum Gizi Seimbang, Mahasiswa Semester VI, COVID-19 ABSTRACTDuring the COVID-19 pandemic, WHO has recommended a balanced nutrition menu, namely that each food menu must include complete nutrition, be it macronutrients such as carbohydrates, proteins, fats, and micronutrients from vitamins and minerals. In boosting the immune system during the COVID-19 pandemic, we must maintain a balanced diet, wash hands with running water and soap and do regular physical activities. This study aims to determine the description of the application of general guidelines for balanced nutrition in semester VI students of the Sam Ratulangi University Public Health Faculty during the COVID-19 pandemic. This research is descriptive quantitative with cross-sectional design with a total sample of 151 people. This research was conducted at the Faculty of Public Health, Sam Ratulangi University in June - August 2020. Data collection was carried out by contacting respondents via WhatsApp then distributing online questionnaires through the google forms application to respondents and measuring using a Likert scale. The results showed that the implementation of general guidelines for balanced nutrition in the sixth semester students of the Faculty of Public Health, Sam Ratulangi University was mostly in the moderate category, namely 128 people (84,7%). As for those included in the less category, as many as 9 people (6%). Keywords: General Guidelines for Balanced Nutrition, Sixth Semester Students, COVID-19

Metabolically Healthy and Unhealthy Obese Phenotypes among Arabs and South Asians:Prevalence and Relationship with Cardiometabolic Indicators

Obesity is a public health crisis in Kuwait. However, not all obese individuals are metabolically unhealthy (MuHO) given the link between obesity and future cardiovascular events. We assessed the prevalence of the metabolically healthy obese (MHO) phenotype and its relationship with high sensitivity C-reactive protein (hs-CRP), serum alanine aminotransferase (ALT), and insulin resistance (HOMA-IR) in Arab and South Asian ethnic groups in Kuwait. The national cross-sectional survey of diabetes and obesity in Kuwait adults aged 18–60 years were analysed. The harmonised definition of metabolic syndrome was used to classify metabolic health. Multinomial logistic regression analysis was used to model the relationship between the MHO and MuHO phenotypes and hs-CRP, ALT and HOMA-IR levels. Overall, the prevalence of MHO for body mass index (BMI)- and waist circumference (WC)-defined obesity was 30.8% and 56.0%, respectively; it was greater in women (60.4% and 61.8%, respectively) than men (39.6% and 38.2%, respectively). Prevalence rates were also lower for South Asians than for Arabs. The MHO phenotype had hs-CRP values above 3 µg/mL for each age group category. Men compared to women, and South Asians compared to Arabs had a lower relative risk for the MHO group relative to the MuHO group. This study shows there is high prevalence of MHO in Kuwait

Melt-Quenched Glasses of Metal–Organic Frameworks

Crystalline solids dominate the field of metal-organic frameworks (MOFs), with access to the liquid and glass states of matter usually prohibited by relatively low temperatures of thermal decomposition. In this work, we give due consideration to framework chemistry and topology to expand the phenomenon of the melting of 3D MOFs, linking crystal chemistry to framework melting temperature and kinetic fragility of the glass-forming liquids. Here we show that melting temperatures can be lowered by altering the chemistry of the crystalline MOF state, which provides a route to facilitate the melting of other MOFs. The glasses formed upon vitrification are chemically and structurally distinct from the three other existing categories of melt-quenched glasses (inorganic nonmetallic, organic, and metallic), and retain the basic metal-ligand connectivity of crystalline MOFs, which connects their mechanical properties to their starting chemical composition. The transfer of functionality from crystal to glass points toward new routes to tunable, functional hybrid glasses.T.D.B. would like to thank Trinity Hall (University of Cambridge) for funding. We thank Diamond Light Source for access to beamline B18 (SP14249-1) that contributed to the results presented here. We thank Dr. Giannantonio Cibin and Dr. Stephen Parry for their assistance with the EXAFS measurements. F.B. thanks EPSRC (grant EP/M00869X/1) and the University of Liverpool for funding. O.K.F. gratefully acknowledges funding from the Army Research Office (project number W911NF-13-1-0229). S.A.T.R. is grateful for funding from the Natural Environment Research Council.This is the final version of the article. It first appeared from the American Chemical Society via https://doi.org/10.1021/jacs.5b1322

Observation of reduced thermal conductivity in a metal-organic framework due to the presence of adsorbates

Whether the presence of adsorbates increases or decreases thermal conductivity in metal-organic frameworks (MOFs) has been an open question. Here we report observations of thermal transport in the metal-organic framework HKUST-1 in the presence of various liquid adsorbates: water, methanol, and ethanol. Experimental thermoreflectance measurements were performed on single crystals and thin films, and theoretical predictions were made using molecular dynamics simulations. We find that the thermal conductivity of HKUST-1 decreases by 40 – 80% depending on the adsorbate, a result that cannot be explained by effective medium approximations. Our findings demonstrate that adsorbates introduce additional phonon scattering in HKUST-1, which particularly shortens the lifetimes of low-frequency phonon modes. As a result, the system thermal conductivity is lowered to a greater extent than the increase expected by the creation of additional heat transfer channels. Finally, we show that thermal diffusivity is even more greatly reduced than thermal conductivity by adsorption

Effect of synthesis conditions on formation pathways of metal organic framework (MOF-5) Crystals

Metal Organic Frameworks (MOFs) represent a class of nanoporous crystalline materials with far reaching potential in gas storage, catalysis, and medical devices. We investigated the effects of synthesis process parameters on production of MOF-5 from terephthalic acid and zinc nitrate in diethylformamide. Under favorable synthesis conditions, we systematically mapped a solid formation diagram in terms of time and temperature for both stirred and unstirred conditions. The synthesis of MOF-5 has been previously reported as a straightforward reaction progressing from precursor compounds in solution directly to the final MOF-5 solid phase product. However, we show that the solid phase formation process is far more complex, invariably transferring through metastable intermediate crystalline phases before the final MOF-5 phase is reached, providing new insights into the formation pathways of MOFs. We also identify process parameters suitable for scale-up and continuous manufacturing of high purity MOF-5

Methane adsorption in metal-organic frameworks containing nanographene linkers: a computational study

Metal-organic framework (MOF) materials are known to be amenable to expansion through elongation of the parent organic linker. For a family of model (3,24)-connected MOFs with the rht topology, in which the central part of organic linker comprises a hexabenzocoronene unit, the effect of the linker type and length on their structural and gas adsorption properties is studied computationally. The obtained results compare favourably with known MOF materials of similar structure and topology. We find that the presence of a flat nanographene-like central core increases the geometric surface area of the frameworks, sustains additional benzene rings, promotes linker elongation and the efficient occupation of the void space by guest molecules. This provides a viable linker modification method with potential for enhancement of uptake for methane and other gas molecules

Water-stable zirconium-based metal-organic framework material with high-surface area and gas-storage capacities.

We designed, synthesized, and characterized a new Zr-based metal-organic framework material, NU-1100, with a pore volume of 1.53 ccg(-1) and Brunauer-Emmett-Teller (BET) surface area of 4020 m(2) g(-1) ; to our knowledge, currently the highest published for Zr-based MOFs. CH4 /CO2 /H2 adsorption isotherms were obtained over a broad range of pressures and temperatures and are in excellent agreement with the computational predictions. The total hydrogen adsorption at 65 bar and 77 K is 0.092 g g(-1) , which corresponds to 43 g L(-1) . The volumetric and gravimetric methane-storage capacities at 65 bar and 298 K are approximately 180 vSTP /v and 0.27 g g(-1) , respectively.OKF, JTH and RQS thank DOE ARPA-E and the Stanford Global Climate and Energy Project for support of work relevant to methane and CO2, respectively. TY acknowledges support by the U. S. Department of Energy through BES Grant No. DE-FG02-08ER46522. WB acknowledges support from the Foundation for Polish Science through the “Kolumb” Program. DFJ acknowledges the Royal Society (UK) for a University Research Fellowship. This material is based upon work supported by the National Science Foundation (grant CHE-1048773).This is the accepted manuscript. The final version is available as 'Water-Stable Zirconium-Based Metal–Organic Framework Material with High-Surface Area and Gas-Storage Capacities' from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/chem.201402895/abstract

Melt-Quenched Glasses of Metal-Organic Frameworks

Crystalline solids dominate the field of metal?organic frameworks (MOFs), with access to the liquid and glass states of matter usually prohibited by relatively low temperatures of thermal decomposition. In this work, we give due consideration to framework chemistry and topology to expand the phenomenon of the melting of 3D MOFs, linking crystal chemistry to framework melting temperature and kinetic fragility of the glass-forming liquids. Here we show that melting temperatures can be lowered by altering the chemistry of the crystalline MOF state, which provides a route to facilitate the melting of other MOFs. The glasses formed upon vitrification are chemically and structurally distinct from the three other existing categories of melt-quenched glasses (inorganic nonmetallic, organic, and metallic), and retain the basic metal?ligand connectivity of crystalline MOFs, which connects their mechanical properties to their starting chemical composition. The transfer of functionality from crystal to glass points toward new routes to tunable, functional hybrid glasses