Porosity of Rigid Dendrimers in Bulk: Interdendrimer Interactions and Functionality as Key Factors

The porous structure of second- and third-generation polyphenylene-type dendrimers was investigated by adsorption of N2, Ar, and CO2 gases, scanning electron microscopy and small-angle X-ray spectroscopy. Rigid dendrimers in bulk are microporous and demonstrate a molecular sieve effect. When using CO2 as an adsorbate gas, the pore size varies from 0.6 to 0.9 nm. This is most likely due to the distances between dendrimer macromolecules or branches of neighboring dendrimers, whose packing is mostly realized due to intermolecular interactions, in particular, π–π interactions of aromatic fragments. Intermolecular interactions prevent the manifestation of the porosity potential inherent to the molecular 3D structure of third-generation dendrimers, while for the second generation, much higher porosity is observed. The maximum specific surface area for the second-generation dendrimers was 467 m2/g when measured by CO2 adsorption, indicating that shorter branches of these dendrimers do not provide dense packing. This implies that the possible universal method to create porous materials for all kinds of rigid dendrimers is by a placement of bulky substituents in their outer layer.

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Third Generation Disadvantage among Mexican Americans

Sociology of Race and Ethnicity ◽

10.1177/2332649217707223 ◽

2017 ◽

Vol 3 (4) ◽

pp. 441-457 ◽

Cited By ~ 5

Author(s):

Vilma Ortiz ◽

Edward Telles

Keyword(s):

Generational Differences ◽

Mexican Americans ◽

Second Generation ◽

Economic Outcomes ◽

Third Generation ◽

Key Factors ◽

Wide Range ◽

Lower Education ◽

Nationally Representative ◽

National Educational Longitudinal Survey

Among Mexican Americans, generational differences in education do not fit with assimilation theory’s predictions of significant improvement from the second to third generation; instead, education for third generation remains similar to the second generation and falls behind that of non-Hispanic whites. Scholars have not examined this educational gap for recent cohorts, nor have they considered a wide range of economic outcomes by generation. Using a nationally representative sample of young adults from the National Educational Longitudinal Survey, we examine various educational and economic outcomes among second- and third-generation Mexican Americans and compare it to whites and blacks. We find that third-generation Mexican Americans have similar outcomes to the second generation and lower education and economic levels than whites and blacks, even when controlling for key factors. Our findings reveal limitations to assimilation theory and suggest that the persistent low status of third-generation Mexican Americans may be largely due to their racialization. These findings coupled with prior research on Mexican Americans point to a consistent pattern of third generation disadvantage, which stands in contrast to second generation advantage.

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A Preview of a Construction of a Crystal Lattice Based on Intermolecular Interactions

Crystals ◽

10.3390/cryst9030159 ◽

2019 ◽

Vol 9 (3) ◽

pp. 159

Author(s):

Vladimír Hejtmánek ◽

Martin Dračínský ◽

Jan Sýkora

Keyword(s):

Intermolecular Interactions ◽

Structural Model ◽

Crystal Packing ◽

General Procedure ◽

3D Structure ◽

One Dimension ◽

X Ray Diffraction ◽

X Ray ◽

Cell Parameters ◽

Repetitive Motif

A general procedure of crystal packing reconstruction using a certain number of intermolecular interactions is introduced and demonstrated on the crystal structure of l-histidine·HCl·H2O. Geometric restrictions based on intermolecular interactions are used for formation of a molecular pair as a basic repetitive motif of the crystal packing. The geometric restrictions were applied gradually within a supervised procedure, narrowing the scope of possible arrangement of two adjacent molecules. Subsequently, a pair of histidine molecules was used for construction of a molecular chain. The chain formed contained translation information on histidine molecules in one dimension, which coincided with one of the cell parameters. Furthermore, the periodicity in the second and third dimensions can be accomplished by chain assembly into sheets (2D), and sheets can be arranged into the final 3D structure. For this purpose, the rest of the available intermolecular interactions could be used to control the mutual assembly of molecular chains and sheets. Complete molecular packing would enable derivation of standard crystallographic parameters that can be used for verification of the structural model obtained. However, the procedure described for construction of the whole 3D structure from molecular chains was not attempted, and is only briefly outlined here. The procedure described can be employed especially when standard crystallographic parameters are not available and traditional methods based on X-ray diffraction fail.

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Aromatase Inhibitors for the Treatment of Breast Cancer: A Journey from the Scratch

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520620666200627204105 ◽

2020 ◽

Vol 20 (17) ◽

pp. 1994-2004 ◽

Cited By ~ 2

Author(s):

Pooja Ratre ◽

Keerti Mishra ◽

Amit Dubey ◽

Amber Vyas ◽

Akhlesh Jain ◽

...

Keyword(s):

Breast Cancer ◽

Estrogen Receptor ◽

Cancer Treatment ◽

Postmenopausal Women ◽

Aromatase Inhibitors ◽

3D Structure ◽

Postmenopausal Breast Cancer ◽

Breast Cancer Treatment ◽

Third Generation ◽

Breast Cancer Chemotherapy

Background: Estrogens are essential for the growth of breast cancer in the case of premenopausal as well as in postmenopausal women. However, most of the breast cancer incidences are reported in postmenopausal women and the concurrent risk surges with an increase in age. Since the enzyme aromatase catalyses essential steps in estrogen biosynthesis, Aromatase Inhibitors (AIs) are effective targeted therapy in patients with Estrogen Receptor positive (ER+) breast cancer. AIs are more effective than Selective Estrogen Receptor Modulators (SERMs) because they block both the genomic and nongenomic activities of ER. Till date, first, second and third-generation AIs have been approved by the FDA. The third-generation AIs, viz. Letrozole, Anastrozole, Exemestane, are currently used in the standard treatment for postmenopausal breast cancer. Methods: Data were collected from Medline, PubMed, Google Scholar, Science Direct through searching of keywords: ‘aromatase’, ‘aromatase inhibitors’, ‘breast cancer’, ‘steroidal aromatase inhibitors’, ‘non-steroidal inhibitors’ and ‘generations of aromatase inhibitors’. Results: In the current scenario of breast cancer chemotherapy, AIs are the most widely used agents which reveal optimum efficacy along with the least side effects. Keeping in view the prominence of AIs in breast cancer therapy, this review covered the detailed description of aromatase including its role in the biosynthesis of estrogen, biochemistry, gene expression, 3D-structure, and information of reported AIs along with their role in breast cancer treatment. Conclusion: AIs are the mainstream solution of the ER+ breast cancer treatment regimen with the continuous improvement of human understanding of the importance of a healthy life of women suffering from breast cancer.

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Second-Generation Inhibitors for the Metalloprotease Neprilysin Based on Bicyclic Heteroaromatic Scaffolds: Synthesis, Biological Activity, and X-Ray Crystal-Structure Analysis

Helvetica Chimica Acta ◽

10.1002/hlca.200590051 ◽

2005 ◽

Vol 88 (4) ◽

pp. 731-750 ◽

Cited By ~ 26

Author(s):

Stefan Sahli ◽

Brian Frank ◽

W. Bernd Schweizer ◽

François Diederich ◽

Denise Blum-Kaelin ◽

...

Keyword(s):

Crystal Structure ◽

Biological Activity ◽

Structure Analysis ◽

Second Generation ◽

Crystal Structure Analysis ◽

X Ray

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Influence of the Presence of Different Alkali Cations and the Amount of Fe(CN)6 Vacancies on CO2 Adsorption on Copper Hexacyanoferrates

Materials ◽

10.3390/ma12203371 ◽

2019 ◽

Vol 12 (20) ◽

pp. 3371 ◽

Cited By ~ 1

Author(s):

Svensson ◽

Grins ◽

Eklöf ◽

Eriksson ◽

Wardecki ◽

...

Keyword(s):

Thermogravimetric Analysis ◽

Prussian Blue ◽

Co2 Adsorption ◽

X Ray Diffraction ◽

Alkali Cations ◽

Prussian Blue Analogue ◽

X Ray ◽

Infra Red ◽

Adsorption Desorption ◽

Adsorption Capability

The CO2 adsorption on various Prussian blue analogue hexacyanoferrates was evaluated by thermogravimetric analysis. Compositions of prepared phases were verified by energy-dispersive X-ray spectroscopy, infra-red spectroscopy and powder X-ray diffraction. The influence of different alkali cations in the cubic Fm3m structures was investigated for nominal compositions A2/3Cu[Fe(CN)6]2/3 with A = vacant, Li, Na, K, Rb, Cs. The Rb and Cs compounds show the highest CO2 adsorption per unit cell, 3.3 molecules of CO2 at 20 C and 1 bar, while in terms of mmol/g the Na compound exhibits the highest adsorption capability, 3.8 mmol/g at 20 C and 1 bar. The fastest adsorption/desorption is exhibited by the A-cation free compound and the Li compound. The influence of the amount of Fe(CN)6 vacancies were assessed by determining the CO2 adsorption capabilities of Cu[Fe(CN)6]1/2 (Fm3m symmetry, nominally 50% vacancies), KCu[Fe(CN)6]3/4 (Fm3m symmetry, nominally 25% vacancies), and CsCu[Fe(CN)6] (I-4m2 symmetry, nominally 0% vacancies). Higher adsorption was, as expected, shown on compounds with higher vacancy concentrations.

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Sa1.4 Do third generation proximal femur nails have better outcome than second generation nails

Injury ◽

10.1016/s0020-1383(13)70071-8 ◽

2013 ◽

Vol 44 ◽

pp. S16

Author(s):

R. Armagan ◽

T. Isik ◽

M. Kanar ◽

H.B. Sezer ◽

O.T. Eren

Keyword(s):

Proximal Femur ◽

Second Generation ◽

Third Generation

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Structural (X-ray), spectroscopic (FT-IR, FT-Raman) and computational (DFT) analysis of intermolecular interactions in 1H-indazole-3-carbaldehyde

Journal of Molecular Structure ◽

10.1016/j.molstruc.2021.130318 ◽

2021 ◽

pp. 130318

Author(s):

Barbara Morzyk-Ociepa ◽

Ksenia Szmigiel-Bakalarz ◽

Markus Nentwig ◽

Oliver Oeckler ◽

Magdalena Malik

Keyword(s):

Intermolecular Interactions ◽

X Ray ◽

Ft Ir ◽

Ft Raman

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The Brown Mite, Bryobia arborea Morgan and Anderson (Acarina: Tetranychidae), on Apple in Nova Scotia.: I. Influence of Intratree Distribution on the Selection of Sampling Units. II. Differences in Habits and Seasonal Trends in Orchards With Bivoltine and Trivoltine Populations. III. Distribution of Diapause Eggs. IV. Hatching of Diapause Eggs

The Canadian Entomologist ◽

10.4039/ent971303-12 ◽

1965 ◽

Vol 97 (12) ◽

pp. 1303-1318 ◽

Cited By ~ 6

Author(s):

H. J. Herbert

Keyword(s):

Nova Scotia ◽

First Generation ◽

Second Generation ◽

Central Area ◽

Third Generation ◽

Apple Trees ◽

Seasonal Trends ◽

Sample Unit ◽

The Third ◽

Selection Of

AbstractIn Nova Scotia one leaf cluster with an adjoining 1 inch of twig taken from the inside of each of 10 apple trees replicated four times is an adequate sample unit to measure the density of the brown mite.The brown mite has one generation with a partial second in some orchards and one with a partial second and partial third in others. The first generation adults in the bivoltine and trivoltine populations lay summer eggs on the leaves and twigs, and diapause eggs on tin twigs. The second generation adults in the bivoltine populations lay only diapause eggs; in the trivoltine populations they lay both summer and diapause eggs. The adults of the third generation lay only diapause eggs.The brown mite is found on both the leaves and woody parts of the tree. In orchards with bivoltine populations the proportion of mites on leaves reached a peak of 80% by mid-July, but thereafter gradually decreased to 10% by the end of August. However, in orchards with trivoltine populations the proportion of mites on leaves reached a peak of 80 to 90% by mid-July, remained constant until mid-August, and thereafter decreased to approximately 40% by the end of August.The number of diapause eggs laid by adults of each generation in both the bivoltine and trivoltine populations varies widely. The eggs are deposited on the trunk as well as on the branches, with the heaviest deposition in the central area of the tree. The diapause eggs laid by adults of the first generation are the last to hatch and those laid by the third generation are the first to hatch the following spring.The factors responsible for the differences in the number of generations and in the number of diapause eggs laid are unknown.

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Structures of designed armadillo-repeat proteins show propagation of inter-repeat interface effects

Acta Crystallographica Section D Structural Biology ◽

10.1107/s2059798315023116 ◽

2016 ◽

Vol 72 (1) ◽

pp. 168-175 ◽

Cited By ~ 7

Author(s):

Christian Reichen ◽

Chaithanya Madhurantakam ◽

Simon Hansen ◽

Markus G. Grütter ◽

Andreas Plückthun ◽

...

Keyword(s):

Second Generation ◽

Body Movement ◽

Recognition System ◽

Third Generation ◽

Peptide Recognition ◽

Repeat Proteins ◽

Peptide Binding Site ◽

Armadillo Repeat ◽

The Stability ◽

Interface Effects

The armadillo repeat serves as a scaffold for the development of modular peptide-recognition modules. In order to develop such a system, three crystal structures of designed armadillo-repeat proteins with third-generation N-caps (YIII-type), four or five internal repeats (M-type) and second-generation C-caps (AII-type) were determined at 1.8 Å (His-YIIIM4AII), 2.0 Å (His-YIIIM5AII) and 1.95 Å (YIIIM5AII) resolution and compared with those of variants with third-generation C-caps. All constructs are full consensus designs in which the internal repeats have exactly the same sequence, and hence identical conformations of the internal repeats are expected. The N-cap and internal repeats M1to M3are indeed extremely similar, but the comparison reveals structural differences in internal repeats M4and M5and the C-cap. These differences are caused by long-range effects of the C-cap, contacting molecules in the crystal, and the intrinsic design of the repeat. Unfortunately, the rigid-body movement of the C-terminal part impairs the regular arrangement of internal repeats that forms the putative peptide-binding site. The second-generation C-cap improves the packing of buried residues and thereby the stability of the protein. These considerations are useful for future improvements of an armadillo-repeat-based peptide-recognition system.

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