Anomalous Relationship between Molecular Size and Diffusivity of Ethane and Ethylene inside Crystals of Zeolitic Imidazolate Framework-11

2019 ◽  
Vol 123 (27) ◽  
pp. 16813-16822 ◽  
Author(s):  
Amineh Baniani ◽  
Christian Chmelik ◽  
Evan M. Forman ◽  
Lei Fan ◽  
Erkang Zhou ◽  
...  
Keyword(s):  
Molecular Size ◽  
Zeolitic Imidazolate Framework ◽  
Anomalous Relationship

Evaluation of the adsorption and desorption properties of zeolitic imidazolate framework-7 for volatile organic compounds through thermal desorption-gas chromatography

2018 ◽  
Vol 10 (40) ◽  
pp. 4894-4901 ◽  
Author(s):  
Ya-Ting Zhao ◽  
Li-Qing Yu ◽  
Xin Xia ◽  
Xin-Yu Yang ◽  
Wei Hu ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Organic Compounds ◽  
Thermal Desorption ◽  
Hydrophobic Interaction ◽  
Molecular Size ◽  
Zeolitic Imidazolate Framework ◽  
Gate Opening ◽  
Volatile Organic ◽  
Stacking Effect ◽  
Adsorption Desorption

The adsorption/desorption properties of VOCs on ZIF-7 were evaluated by TD-GC. It was found that there are hydrophobic interaction, π–π stacking effect, molecular size effect and “gate-opening” effect between VOCs and ZIF-7.

Characterization of Recombinant Human Coagulation Factor XFriuli

1996 ◽  
Vol 75 (02) ◽  
pp. 313-317 ◽  
Author(s):  
D J Kim ◽  
A Girolami ◽  
H L James
Keyword(s):  
Catalytic Domain ◽  
Coagulation Factor ◽  
Molecular Size ◽  
Binding Pocket ◽  
Site Directed Mutagenesis ◽  
Bleeding Tendency ◽  
Factor X ◽  
Amino Terminal ◽  
Normal Plasma ◽  
Plasma Factor

SummaryNaturally occurring plasma factor XFriuli (pFXFr) is marginally activated by both the extrinsic and intrinsic coagulation pathways and has impaired catalytic potential. These studies were initiated to obtain confirmation that this molecule is multi-functionally defective due to the substitution of Ser for Pro at position 343 in the catalytic domain. By the Nelson-Long site-directed mutagenesis procedure a construct of cDNA in pRc/CMV was derived for recombinant factor XFriuli (rFXFr) produced in human embryonic (293) kidney cells. The rFXFr was purified and shown to have a molecular size identical to that of normal plasma factor X (pFX) by gel electrophoretic, and amino-terminal sequencing revealed normal processing cleavages. Using recombinant normal plasma factor X (rFXN) as a reference, the post-translational y-carboxy-glutamic acid (Gla) and (β-hydroxy aspartic acid (β-OH-Asp) content of rFXFr was over 85% and close to 100%, respectively, of expected levels. The specific activities of rFXFr in activation and catalytic assays were the same as those of pFXFr. Molecular modeling suggested the involvement of a new H-bond between the side-chains of Ser-343 and Thr-318 as they occur in anti-parallel (3-pleated sheets near the substrate-binding pocket of pFXFr. These results support the conclusion that the observed mutation in pFXFr is responsible for its dysfunctional activation and catalytic potentials, and that it accounts for the moderate bleeding tendency in the homozygous individuals who possess this variant procoagulant.

Suppressive Effect of Dextran on Platelet Adhesiveness

1966 ◽  
Vol 16 (03/04) ◽  
pp. 384-394 ◽  
Author(s):  
S Cronberg ◽  
B Robertson ◽  
Inga Marie Nilsson ◽  
J.-E Niléhn
Keyword(s):  
Molecular Weight ◽  
Bleeding Time ◽  
Slight Modification ◽  
Molecular Size ◽  
Suppressive Effect ◽  
Factor Ix ◽  
Factor V ◽  
Platelet Adhesiveness ◽  
History Of ◽  
Mean Molecular Weight

Summary43 normal volunteers, 3 patients with thrombophlebitis, and 1 patient with a high platelet adhesiveness and a history of thrombophlebitis have received dextran and its action on the mechanism of haemostasis has been studied. Platelet adhesiveness has been investigated by a slight modification of Hellem’s methods for whole blood and plasma. Dextran with a mean molecular weight of 70,000 produced a markedly lowered platelet adhesiveness together with a moderate prolongation of the Ivy bleeding time. Factor VIII was decreased by about 50% and factor V, factor IX and fibrinogen were decreased slightly more than could be expected from haemodilution alone. No fibrinolysis occurred. Dextran of lower molecular size was less potent. The possible use of dextrans as a thrombosis prophylactic agent is discussed.

Theoretical and Experimental Evaluation of the Effect of Fluorinated Substituent on the Topological Landscape and Thermodynamic Stability of Zeolitic Imidazolate Framework Polymorphs

2018 ◽  
Author(s):  
Mihails Arhangelskis ◽  
Athanassis Katsenis ◽  
Novendra Novendra ◽  
Zamirbek Akimbekov ◽  
Dayaker Gandrath ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Mechanochemical Synthesis ◽  
Thermodynamic Stability ◽  
Experimental Evaluation ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Zeolitic Imidazolate Framework ◽  
Functional Theory ◽  
Calorimetric Measurements ◽  
And Calorimetry

By combining mechanochemical synthesis and calorimetry with theoretical calculations, we demonstrate that dispersion-corrected periodic density functional theory (DFT) can accurately survey the topological landscape and predict relative energies of polymorphs for a previously inaccessible fluorine-substituted zeolitic imidazolate framework (ZIF). Experimental screening confirmed two out of three theoretically anticipated polymorphs, and the calorimetric measurements provided an excellent match to theoretically calculated energetic difference between them.<br>

Medicinal Chemistry Database GDBMedChem

2019 ◽  
Author(s):  
Mahendra Awale ◽  
Finton Sirockin ◽  
Nikolaus Stiefl ◽  
Jean-Louis Reymond
Keyword(s):  
Small Molecules ◽  
Natural Product ◽  
Medicinal Chemistry ◽  
3D Visualization ◽  
Molecular Size ◽  
Similarity Searching ◽  
Complex Molecules ◽  
Synthetic Accessibility ◽  
Simple Chemical ◽  
Reduced Complexity

<div>The generated database GDB17 enumerates 166.4 billion possible molecules up to 17 atoms of C, N, O, S and halogens following simple chemical stability and synthetic feasibility rules, however medicinal chemistry criteria are not taken into account. Here we applied rules inspired by medicinal chemistry to exclude problematic functional groups and complex molecules from GDB17, and sampled the resulting subset evenly across molecular size, stereochemistry and polarity to form GDBMedChem as a compact collection of 10 million small molecules.</div><div><br></div><div>This collection has reduced complexity and better synthetic accessibility than the entire GDB17 but retains higher sp 3 - carbon fraction and natural product likeness scores compared to known drugs. GDBMedChem molecules are more diverse and very different from known molecules in terms of substructures and represent an unprecedented source of diversity for drug design. GDBMedChem is available for 3D-visualization, similarity searching and for download at http://gdb.unibe.ch.</div>

Enhanced Stability and Controlled Delivery of MOF Encapsulated Vaccines and Their Immunogenic Response In Vivo

2018 ◽  
Author(s):  
Michael Luzuriaga ◽  
Raymond P. Welch ◽  
Madushani Dharmawardana ◽  
Candace Benjamin ◽  
Shaobo Li ◽  
...  
Keyword(s):  
Viral Vector ◽  
Controlled Delivery ◽  
Conformational Structure ◽  
Spectroscopy Analysis ◽  
Zeolitic Imidazolate Framework ◽  
Structural Conformation ◽  
Depth Study ◽  
Viral Nanoparticle

<div><div><div><p>Vaccines have an innate tendency to lose their structural conformation upon environmental and chemical stressors. A loss in conformation reduces the therapeutic ability to prevent the spread of a pathogen. Herein, we report an in-depth study of zeolitic imidazolate framework-8 (ZIF-8) and its ability to provide protection for a model viral vector against dena- turing conditions. The immunoassay and spectroscopy analysis together demonstrate enhanced thermal and chemical stability to the conformational structure of the encapsulated viral nanoparticle. The long-term biological activity of this virus-ZIF composite was investigated in animal models to further elucidate the integrity of the encapsulated virus, the bio-safety, and immunogenicity of the overall composite. Additionally, histological analysis found no observable tissue damage in the skin or vital organs in mice, following multiple subcutaneous administrations. This study shows that ZIF-based protein composites are strong candidates for improved preservation of proteinaceous drugs, are biocompatible, and capable of controlling the release and adsorption of drugs in vivo.</p></div></div></div>

New approaches for the determination of dextran in the sugar production process

2018 ◽  
pp. 138-146 ◽  
Author(s):  
Karin Abraham ◽  
Eckhard Flöter
Keyword(s):  
Molecular Mass ◽  
Mass Distribution ◽  
Molecular Mass Distribution ◽  
Molecular Size ◽  
Mass Variation ◽  
Negative Effects ◽  
New Approaches ◽  
Precise Knowledge ◽  
Enzyme Application

The presence of polysaccharides in cane and beet raw juices causes several negative effects during the sugar manufacture. These are usually mitigated by enzymatic decomposition of dextrans. Such effects not only depend on the content, but also on the molecular mass distribution. This means that the different dextran fractions specifically affect the process. An accurate process control hence requires the most precise knowledge about the existing content and the molecular mass distribution present. A detailed understanding of the specific processing problems and also a targeted enzyme application hence requires the determination of a total dextran content and also its characterization including the differentiation between the different dextran fractions. An accurate analytical tool which equally satisfies industrial applicability is still lacking. To improve on this situation, two new approaches for the determination of dextran were developed and benchmarked against the commonly used and established Haze Method, which is rather inaccurate and also sensitive to molecular mass variation. The two new approaches are both based on polarimetry. These two methods indicate to be superior over the Haze Method with respect two molecular mass variation and hence enable the determination of a broader molecular size range including also low molecular mass dextrans.

Determination of the Size Distribution of Dissolved Organics in Effluents

1973 ◽  
Vol 8 (1) ◽  
pp. 1-15 ◽  
Author(s):  
L.A. Addie ◽  
K.L. Murphy ◽  
J.L. Robertson
Keyword(s):  
Size Distribution ◽  
Biological Treatment ◽  
Oxygen Demand ◽  
Molecular Size ◽  
Monitoring Systems ◽  
Clean Surface ◽  
Sephadex Column ◽  
Dissolved Organics ◽  
Molecular Size Distribution

Abstract The importance of removing the small amounts of residual organics is increasing as the sources of clean surface water decrease. Knowledge of the nature of these soluble residual organics will be needed in order to assess the type of treatment required for their removal. Residual organics in three different biological treatment plants were analyzed and compared. An attempt was made to characterize these organics by a molecular size distribution on a Sephadex column monitored by differential ultraviolet and refractive index detectors. The organic carbon and chemical oxygen demand of the fractions collected from the column was also determined. An investigation of some of the problems inherent in the monitoring systems was conducted.

Natural Macromolecules with Protective and Antitumor Activity

2018 ◽  
Vol 18 (5) ◽  
pp. 675-683 ◽  
Author(s):  
Cioanca Oana ◽  
Trifan Adriana ◽  
Cornelia Mircea ◽  
Scripcariu Dragos ◽  
Hancianu Monica
Keyword(s):  
Immune Response ◽  
Antitumor Activity ◽  
Tumor Cells ◽  
Biological Activities ◽  
Molecular Size ◽  
Plant Lectins ◽  
Natural Toxins ◽  
Glycosidic Bonds ◽  
Novel Drug

This review summarizes the literature data regarding plant lectins as novel drug sources in the prevention or treatment of cancer. Moreover, such compounds have been described as natural toxins that possess different biological activities (cytotoxic, antitumor, antimutagenic and anticarcinogenic properties). This activity depends greatly on their structure and affinity. Most of the mushroom heterosides are known as β-glucans with β-(1→3)-glycosidic bonds. It is thought that their conformation, bonds, molecular size can modulate the immune response by triggering different receptors. The mechanism on normal and tumor cells of various plant and mushroom polysaccharides and lectins is briefly presented in this paper.

Discovery of THICZs as Chemical Sensors: Synthesis, Spectrophotometric,Voltammetric and DFT Studies

2019 ◽  
Vol 09 ◽  
Author(s):  
Mardia T. El Sayed ◽  
Ibrahim H.I. Habib ◽  
Nermien M. Sabry ◽  
Sergey A. Pisarev ◽  
Mohamed El-Naggar ◽  
...  
Keyword(s):  
Electrochemical Behaviour ◽  
Molecular Size ◽  
Active Species ◽  
Carbon Paste ◽  
Reversible Redox ◽  
Energy Relationships ◽  
Linear Solvation Energy ◽  
Solute Interactions ◽  
Homo Lumo ◽  
Paste Electrode

Absorption spectra of tetrahydro[3,2-b]indolo-carbazoles (THICZs) with various molecular size and alkyl tails have been recorded in various solvents in the range between 200 to 600 nm. The photo physical behaviour of dissolved THICZs depends on the nature of its environment. The solvatochromic behaviours of THICZs and solvent solute interactions can be analysed by means of linear solvation energy relationships concept proposed by Kamlet and Taft. Compound 4 show excellent properties for sensing small molecules. The electrochemical behaviour of some THICZs was investigated at carbon paste electrode where two electrode reactions were involved, irreversible oxidation-one electron transfer and quasi-reversible redox reactions forming phenolic followed by quinolone moiety electro active species. The DFT-calculated molecular orbital energies (B3LYP/6-31G) and HOMO-LUMO gaps for some presented indolocarbazoles have been performed.

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