scholarly journals Characterising Supramolecular Architectures in Crystals Featuring I⋯Br Halogen Bonding: Persistence of X⋯X’ Secondary-Bonding in Their Congeners

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 433
Author(s):  
Edward R. T. Tiekink
Keyword(s):  
Crystal Engineering ◽  
Three Dimensional ◽  
Halogen Bonding ◽  
Group Symmetry ◽  
Type I ◽  
Type Ii ◽  
Cell Parameters ◽  
Supramolecular Architectures ◽  
Structural Database ◽  
Secondary Bonding

The Cambridge Structural Database was surveyed for crystals featuring I⋯Br secondary-bonding in their supramolecular assemblies occurring independently of other obvious supramolecular synthons and devoid of other halogen bonding interactions. In all, 41 crystals satisfied these criteria, with nine examples of zero-dimensional aggregation (uniformly two-molecule aggregates) and 30 one-dimensional chains of varying topology (linear, zigzag and helical). There is one example each of two- and three-dimensional patterns. Type-I, type-II and intermediate bonding situations are apparent; for type-II bonding, the ratio of iodide:bromide functioning as the electrophile is 2:1. Most molecules participated, on average, in one I⋯Br contact, although smaller numbers of half (zero-dimensional) or two contacts (two- and three-dimensional) were observed. The propensity of the formation of related halogen bonding interactions in congeners of the 41 investigated crystals was also studied. Congeners were apparent for 11 crystals, with seven of these exhibiting isostructural relationships, in terms of space-group symmetry and unit-cell parameters. Isostructural relationships do not ensure the formation of analogous aggregation patterns, particularly and in accord with expectation, for the lighter halides. When formed, often distinct aggregation patterns are observed despite the isostructural relationships. Hetero-atomic halogen bonding offers surprises and opportunities in crystal engineering endeavours.

scholarly journals Altered affinity of insulin-like growth factor II (IGF-II) for receptors and IGF-binding proteins, resulting from limited modifications of the IGF-II molecule

1991 ◽  
Vol 278 (1) ◽  
pp. 249-254 ◽  
Author(s):  
Y Oh ◽  
M W Beukers ◽  
H M Pham ◽  
P A Smanik ◽  
M C Smith ◽  
...  
Keyword(s):  
Amino Acids ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Type I ◽  
Type Ii ◽  
Factor Ii ◽  
N Terminus ◽  
Severe Impairment ◽  
Igf Binding ◽  
Terminal Amino

The binding affinities of seven analogues of recombinant human insulin-like growth factor II (hIGF-II) were characterized for the IGF type-I and type-II receptors and insulin receptors, as well as for IGF-binding protein (IGFBP)-1, IGFBP-2, IGFPB-3 and human serum IGFBPs. A switch of two of the three cysteine bridges in hIGF-II, 9-47 and 46-51 to 9-46 and 47-51, severely impaired the binding of this analogue to all receptors and to the IGFBPs. The affinities for the IGF type-I receptor and the IGFBPs were decreased over 100-fold, while the binding to the insulin receptor and the IGF type-II receptor was less affected, with a 6-10-fold decrease in affinity. Slight modifications of the N-terminus had only minor effects upon the binding of hIGF-II to the IGFBPs or to the receptors. Deletion of both the N-terminal amino acid and the two C-terminal amino acids resulted in moderate decreases in affinity, with a 60% decrease in affinity for IGFBP-1 and the IGF type-I receptor. Acetylation of the N-terminus of Ala1 and the epsilon-nitrogen of Lys65 decreased the affinity, by 60-90%, of hIGF-II for all of the IGFBPs and receptors. The experiments involving acetylation of IGF-II or switching of its cysteine bridges indicated that these modifications (no substitution, deletion or addition of any of the 67 amino acids of hIGF-II) may lead to a severe impairment of the binding affinity of IGF-II for both the IGFBPs and the receptors. Acetylation of the epsilon-nitrogen of Lys65, which causes a charge change, or alteration of the three-dimensional structure, as shown by the cysteine bridge switch, lead to a severe impairment of the binding affinity for the binding proteins and for the receptors. In general, care should be taken with the synthesis of analogues and the interpretation of resulting binding data, since affinity alterations ascribed to amino acid changes may instead be caused by alterations of the charge or the three-dimensional structure of the protein.

scholarly journals Study On The Application of Preoperative Three-Dimensional CT Angiography of Perigastric Arteries In Laparoscopic Radical Gastrectomy

2022 ◽  
Author(s):  
Peng Liu ◽  
Wenbin Yu ◽  
Meng Wei ◽  
Danping Sun ◽  
Xin Zhong ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Blood Loss ◽  
Three Dimensional ◽  
Classification Model ◽  
Type I ◽  
Radical Gastrectomy ◽  
Type Ii ◽  
Type Iii ◽  
Type Iv ◽  
Type V

Abstract Objection: To investigate the clinical value and significance of preoperative three-dimensional computerized tomography angiography (CTA) in laparoscopic radical gastrectomy for gastric cancer.Methods: The clinical data were analyzed retrospectively from 214 gastric cancer patients. We grouped according to whether to perform CTA. The gastric peripheral artery was classified according to CTA images of patients in the CTA group, and we compared and analyzed the difference of the data between the two groups.Results: The celiac trunk was classified according to Adachi classification: Type I (118/125, 94.4%),Type II (3/125, 2.4%),Type III (0/125, 0%),Type IV (1/125, 0.8%),Type V (2/125, 1.6%),Type VI (1/125, 0.8%).Hepatic artery classification was performed according to Hiatt classification standard:Type I (102/125, 81.6％),Type II (9/125, 7.2%),Type III (6/125, 4.8%),Type IV (2/125, 1.6%),Type V (3/125, 2.4%),Type VI (0, 0%),Others (3/125, 2.4%).And this study combined vascular anatomy and clinical surgical risk to establish a new splenic artery classification model. It was found that the operation time and estimated blood loss in the CTA group were significantly lower than those in the non-CTA group. In addition, the blood loss in the CTA group combined with ICG (Indocyanine Green) labeled fluorescence laparoscopy was significantly less than that in the group without ICG labeled. Conclusion: Preoperative CTA can objectively evaluate the vascular course and variation of patients, and then avoid the risk of operation, especially in combination with ICG labeled fluorescence laparoscopy, can further improve the quality of operation.

scholarly journals The severity of developmental dysplasia of the hip does not correlate with the abnormality in pelvic incidence

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Rongshan Cheng ◽  
Muyin Huang ◽  
Willem Alexander Kernkamp ◽  
Huiwu Li ◽  
Zhenan Zhu ◽  
...  
Keyword(s):  
Pelvic Incidence ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Developmental Dysplasia ◽  
Control Group ◽  
Type I ◽  
Type Ii ◽  
Computed Tomography Images ◽  
Significant Difference ◽  
Dysplasia Of The Hip

Abstract Background The purpose of this study was to investigate the association between the severity of Developmental dysplasia of the hip (DDH) and the abnormality in pelvic incidence (PI). Methods This was a retrospective study analyzing 53 DDH patients and 53 non-DDH age-matched controls. Computed tomography images were used to construct three-dimensional pelvic model. The Crowe classification was used to classify the severity of DDH. The midpoint of the femoral head centers and sacral endplates were projected to the sagittal plane of the pelvis. The PI was defined as the angle between a line perpendicular to the sacral plate at its midpoint and a line connecting this point to the axis of the femoral heads. Independent sample t-tests were used to compare the differences between the PI of DDH group and the non-DDH controls group. Kendall’s coefficient of concordance was used to determine the correlation between the severity of DDH and PI. Results Patients with DDH had a significantly (p = 0.041) higher PI than the non-DDH controls (DDH 47.6 ± 8.2°, normal 44.2 ± 8.8°). Crowe type I patients had a significantly (p = 0.038) higher PI (48.2 ± 7.6°) than the non-DDH controls. No significant difference between the PI in Crowe type II or III patients and the PI in non-DDH controls were found (Crowe type II, 50.2 ± 9.6°, p = 0.073; Crowe type III, 43.8 ± 7.2°, p = 0.930). No correlation was found between the severity of DDH and the PI (r = 0.091, p = 0.222). Conclusions No correlation was found between the severity of DDH and the PI. The study confirmed that the PI in DDH (Crowe type I) group was higher than that of the non-DDH control group, while the PI does not correlate with the severity of DDH.

scholarly journals Preliminary Deformational Studies on a Finite Element Model of the Nasal Septum Reveals Key Areas for Septal Realignment and Reconstruction

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kyrin Liong ◽  
Shu Jin Lee ◽  
Heow Pueh Lee
Keyword(s):  
Nasal Septum ◽  
Preoperative Planning ◽  
Three Dimensional ◽  
Element Model ◽  
Septal Cartilage ◽  
Type I ◽  
Type Ii ◽  
Anterior Nasal Spine ◽  
Force Direction ◽  
Three Dimensional Models

Background. With the current lack of clinically relevant classification methods of septal deviation, computer-generated models are important, as septal cartilage is indistinguishable on current imaging methods, making preoperative planning difficult. Methods. Three-dimensional models of the septum were created from a CT scan, and incremental forces were applied. Results. Regardless of the force direction, with increasing force, the septum first tilts (type I) and then crumples into a C shape (type II) and finally into an S shape (type III). In type I, it is important to address the dislocation in the vomer-ethmoid cartilage junction and vomerine groove, where stress is concentrated. In types II and III, there is intrinsic fracture and shortening of the nasal septum, which may be dislocated off the anterior nasal spine. Surgery aims to relieve the posterior buckling and dislocation, with realignment of the septum to the ANS and possible spreader grafts to buttress the fracture sites. Conclusion. By identifying clinically observable septal deviations and the areas of stress concentration and dislocation, a straighter, more stable septum may be achieved.

scholarly journals Identification of actin-, alpha-actinin-, and vinculin-containing plaques at the lateral membrane of epithelial cells.

1986 ◽  
Vol 102 (5) ◽  
pp. 1843-1852 ◽  
Author(s):  
D Drenckhahn ◽  
H Franz
Keyword(s):  
Plasma Membrane ◽  
Cross Sections ◽  
Three Dimensional ◽  
Intercellular Junctions ◽  
Classical Type ◽  
Type I ◽  
Type Ii ◽  
Microscopic Studies ◽  
Prostatic Epithelium ◽  
Human Intestinal Epithelium

In this paper, a new type of spot desmosome-like junction (type II plaque) is described that is scattered along the entire lateral plasma membrane of rat and human intestinal epithelium. Ultrastructurally type II plaques differed from the classical type of epithelial spot desmosome ("macula adherens", further denoted as type I desmosome) by weak electron density of the membrane-associated plaque material, association of the plaques with microfilaments rather than intermediate filaments, and poorly visible material across the intercellular space. Thus, type II plaques resemble cross-sections of the zonula adherens. Immunofluorescence-microscopic studies were done using antibodies to a main protein associated with the plaques of type I desmosomes (desmoplakin I) and to the three major proteins located at the plaques of the zonula adherens (actin, alpha-actinin, and vinculin). Two types of plaques were visualized along the lateral surface of intestinal and prostatic epithelium: (a) the type I desmosomes, which were labeled with anti-desmoplakin but did not bind antibodies to actin, alpha-actinin, and vinculin, and (b) a further set of similarly sized plaques, which bound antibodies to actin, alpha-actinin, and vinculin but were not stained with anti-desmoplakin. Three-dimensional computer reconstruction of serial sections double-labeled with anti-desmoplakin and anti-alpha-actinin further confirmed that both types of plaques are spatially completely separated from each other along the lateral plasma membrane. The computer graphs further revealed that the actin-, alpha-actinin-, and vinculin-containing plaques have the tendency to form clusters, a feature also typical of type II plaques. It is suggested that the type II plaques represent spot desmosome-like intercellular junctions, which, like the zonula adherens, appear to be linked to the actin filament system. As the type II plaques cover a considerable part of the lateral cell surface, they might play a particular role in controlling cellular shape and intercellular adhesion.

Utilizing plane group symmetry to favor noncentrosymmetry in three-dimensional crystals

2020 ◽  
Vol 98 (7) ◽  
pp. 327-331
Author(s):  
Ren A. Wiscons ◽  
Adam J. Matzger
Keyword(s):  
Crystal Structures ◽  
Second Harmonic ◽  
Three Dimensional ◽  
Halogen Bonding ◽  
Two Dimensions ◽  
Group Symmetry ◽  
Inversion Symmetry ◽  
Closest Packing ◽  
Symmetry Operators ◽  
Plane Group

Materials that lack inversion symmetry (noncentrosymmetric) demonstrate a diversity of desirable optical and electronic properties in bulk such as second harmonic generation, chiral emission, and piezo-, pyro-, and ferro-electricity. Unfortunately, it is challenging to reliably access noncentrosymmetric packing motifs because the closest packing of molecules is often achieved through inversion symmetry operators, leading to the relatively low occurrence of noncentrosymmetry in organic crystals. In this study, the occurrence of noncentrosymmetry in materials that adopt planar packing motifs is investigated because molecular species achieve closest packing in two dimensions through rotations and (or) glides, symmetry operators that do not individually lead to centrosymmetry. It is found that of the 18 crystal structures investigated here adopting planar packing motifs, 13 structures (72%) are noncentrosymmetric showing in-plane polarization. The 13 noncentrosymmetric crystal structures differ from the centrosymmetric structures by directional halogen bonding interactions or steric collisions that align the polarization directions of neighboring layers, leading to bulk structural polarity. The results from this investigation will be of use for designing noncentrosymmetric materials for application in optical and electronic devices.

scholarly journals A Survey of Supramolecular Aggregation Based on Main Group Element⋯Selenium Secondary Bonding Interactions—A Survey of the Crystallographic Literature

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 503 ◽  
Author(s):  
Edward R. T. Tiekink
Keyword(s):  
Crystal Structures ◽  
Three Dimensional ◽  
Main Group ◽  
Group Element ◽  
The Other ◽  
One Dimensional ◽  
Supramolecular Architectures ◽  
Main Group Element ◽  
Supramolecular Aggregation ◽  
Secondary Bonding

The results of a survey of the crystal structures of main group element compounds (M = tin, lead, arsenic, antimony, bismuth, and tellurium) for intermolecular M⋯Se secondary bonding interactions is presented. The identified M⋯Se interactions in 58 crystals can operate independent of conventional supramolecular synthons and can sustain zero-, one-, two, and, rarely, three-dimensional supramolecular architectures, which are shown to adopt a wide variety of topologies. The most popular architecture found in the crystals stabilized by M⋯Se interactions are one-dimensional chains, found in 50% of the structures, followed by zero-dimensional (38%). In the majority of structures, the metal center forms a single M⋯Se contact; however, examples having up to three M⋯Se contacts are evident. Up to about 25% of lead(II)-/selenium-containing crystals exhibit Pb⋯Se tetrel bonding, a percentage falling off to about 15% in bismuth analogs (that is, pnictogen bonding) and 10% or lower for the other cited elements.

scholarly journals Capabilities and limitations of a (3 + d)-dimensional incommensurately modulated structure as a model for the derivation of an extended family of compounds: example of the scheelite-like structures

2008 ◽  
Vol 64 (1) ◽  
pp. 12-25 ◽  
Author(s):  
Alla Arakcheeva ◽  
Gervais Chapuis
Keyword(s):  
Extended Family ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Unit Cell ◽  
Group Symmetry ◽  
Dimensional Structure ◽  
Basic Unit ◽  
Modulated Structure ◽  
Three Dimensional Structure ◽  
Cell Parameters

The previously reported incommensurately modulated scheelite-like structure KNd(MoO4)2 has been exploited as a natural (3 + 1)-dimensional superspace model to generate the scheelite-like three-dimensional structure family. Although each member differs in its space-group symmetry, unit-cell parameters and compositions, in (3 + 1)-dimensional space, they share a common superspace group, a common number of building units in the basic unit cell occupying Wyckoff sites with specific coordinates (x, y, z) and specific basic unit-cell axial ratios (c/a, a/b, b/c) and angles. Variations of the modulation vector q, occupation functions and t 0 are exploited for the derivation. Eight topologically and compositionally different known structures are compared with their models derived from the KNd(MoO4)2 structure in order to evaluate the capabilities and limitations of the incommensurately modulated structure to act as a superspace generating model. Applications of the KNd(MoO4)2 structure as a starting model for the refinement and prediction of some other modulated members of the family is also illustrated. The (3 + 1)-dimensional presentation of the scheelite-like structures reveals new structural relations, which remain hidden if only conventional three-dimensional structure descriptions are applied.

Anion Templated Crystal Engineering of Halogen Bonding Tripodal Tris(halopyridinium) Compounds

2020 ◽  
Author(s):  
Emer Foyle ◽  
Nicholas White
Keyword(s):  
Crystal Engineering ◽  
Self Assembly ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Halogen Bonds ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Structural Database ◽  
Van Der Waals Radii

<div>In this work four new tripodal tris(halopyridinium) receptors containing potentially halogen</div><div>bonding groups were prepared. The ability of the receptors to bind anions in competitive</div><div>CD<sub>3</sub>CN/d<sub>6</sub>-DMSO was studied using <sup>1</sup>H NMR titration experiments, which revealed that the</div><div>receptors bind chloride anions more strongly than more basic acetate or other halide ions.</div><div>The solid state self–assembly of the tripodal receptors with halide anions was investigated by</div><div>X-ray crystallography. The nature of the structures was dependent on the choice of halide</div><div>anion, as well as the crystallisation solvent. Halogen bond lengths as short as 80% of the sum</div><div>of the van der Waals radii were observed, which is shorter than any halogen bonds involving</div><div>halopyridinium receptors in the Cambridge Structural Database.</div>

Anion Templated Crystal Engineering of Halogen Bonding Tripodal Tris(halopyridinium) Compounds

2020 ◽  
Author(s):  
Emer Foyle ◽  
Nicholas White
Keyword(s):  
Crystal Engineering ◽  
Self Assembly ◽  
Halogen Bond ◽  
Halogen Bonding ◽  
Halogen Bonds ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Structural Database ◽  
Van Der Waals Radii

<div>In this work four new tripodal tris(halopyridinium) receptors containing potentially halogen</div><div>bonding groups were prepared. The ability of the receptors to bind anions in competitive</div><div>CD<sub>3</sub>CN/d<sub>6</sub>-DMSO was studied using <sup>1</sup>H NMR titration experiments, which revealed that the</div><div>receptors bind chloride anions more strongly than more basic acetate or other halide ions.</div><div>The solid state self–assembly of the tripodal receptors with halide anions was investigated by</div><div>X-ray crystallography. The nature of the structures was dependent on the choice of halide</div><div>anion, as well as the crystallisation solvent. Halogen bond lengths as short as 80% of the sum</div><div>of the van der Waals radii were observed, which is shorter than any halogen bonds involving</div><div>halopyridinium receptors in the Cambridge Structural Database.</div>

Sign in / Sign up

Export Citation Format

Share Document