scholarly journals Influence of coracoglenoid space on scapular neck fracture stability: biomechanical study

2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Junfeng Chen ◽  
Wei Zhang ◽  
Gang Pang ◽  
Qingling Meng ◽  
Youyu Zhu ◽  
...  
Keyword(s):  
Failure Load ◽  
Anatomical Variation ◽  
Biomechanical Study ◽  
Interindividual Variation ◽  
Type I ◽  
Type Ii ◽  
Average Maximum ◽  
Neck Fracture ◽  
The Stability ◽  
Scapular Neck Fractures

Abstract Background The anatomical variation of the coracoglenoid space has the potential to influence the stability of scapular neck fractures. This paper aimed to investigate the mechanical mechanism underlying the influence of different coracoglenoid space types on scapular neck fractures by morphometric analysis and biomechanical experiments. Methods The morphology of 68 dried scapulae (left: 36; right: 32) was studied. Two variables, the length of the coracoglenoid distance (CGD) and the coracoglenoid notch (CGN), were measured. The distribution of CGN/CGD × 100% was used to identify the morphology of the coracoglenoid space. Each specimen was tested for failure under static axial compression loading. The average failure load, stiffness, and energy were calculated. Results Two coracoglenoid space types were identified. The incidence of Type I (‘‘hook’’ shape) was 53%, and that of Type II (‘‘square bracket’’ shape) was 47%. The CGD and CGN were significantly higher for type I than type II (13.81 ± 0.74 mm vs. 11.50 ± 1.03 mm, P < 0.05; 4.74 ± 0.45 mm vs. 2.61 ± 0.45 mm, P < 0.05). The average maximum failure load of the two types was 1270.82 ± 318.85 N and 1529.18 ± 467.29 N, respectively (P = 0.011). The stiffness and energy were significantly higher for type II than type I (896.75 ± 281.14 N/mm vs. 692.91 ± 217.95 N/mm, P = 0.001; 2100.38 ± 649.54 N × mm vs. 1712.71 ± 626.02 N × mm, P = 0.015). Conclusions There was great interindividual variation in the anatomical morphology of the coracoglenoid space. Type I (hook-like) spaces bore lower forces, were less stiff, and bore less energy, which may constitute an anatomical predisposition to scapular neck fractures.

Influence of Coracoglenoid Space on the Stability of Scapular Neck Fractures: Biomechanical Study

2021 ◽  
Author(s):  
Junfeng Chen ◽  
Wei Zhang ◽  
Gang Pang ◽  
Qingling Meng ◽  
Youyu Zhu ◽  
...  
Keyword(s):  
Anatomical Variation ◽  
Compressive Load ◽  
Biomechanical Study ◽  
Load Test ◽  
Mean Values ◽  
Average Maximum ◽  
Significant Difference ◽  
The Mean ◽  
The Stability ◽  
Scapular Neck Fractures

Abstract Background: The anatomical variation of the coracoglenoid space has the potential to influence the stability of scapular neck fractures. This paper aimed to investigate the path-mechanical mechanisms of different types of coracoglenoid space on the scapular neck fractures by morphometric analysis and biomechanical experiments.Methods: A total of 68 dry scapulae (left: 36; right: 32) were collected, the types of coracoglenoid space delimited by a boundary based on the ratio of the mean values of CGD to the mean values of CGN. Each specimen of a different type was under static axial compressive load test to failure. The average failure loads, stiffness, and energy for each specimen were calculated.Results: Two types of coracoglenoid space were identified. The incidence of Type Ⅰ (2.4 < ratio ≤ 3.5) (‘‘hook’’ shape) was found to be 53%, that of Type Ⅱ (3.5 < ratio ≤ 5.0) (‘‘square bracket’’ shape) was found to be 47%. There was no statistically significant difference in the two types between different body sides (P > 0.05). The average maximum failure load of these two types was 1270.82 ± 318.85 N and 1529.18 ± 467.29 N, respectively (P = 0.011). The measures of the average failure stiffness and energy of Type Ⅱ were significantly higher than Type Ⅰ (896.75 ± 281.14 N/mm vs. 692.91 ± 217.9 5N/mm, P = 0.001; 2100.38 ± 649.54 N⋅mm vs. 1712.71 ± 626.02 N⋅mm, P = 0.015, respectively).Conclusions: The variation of coracoglenoid space is large in different individuals, hook-like space is associated with fewer forces, stiffness, and energy, which constitute an anatomical predisposition to the scapular neck fractures.

A delayed rectifier conductance in type I hair cells of the mouse utricle

1996 ◽  
Vol 76 (2) ◽  
pp. 995-1004 ◽  
Author(s):  
A. Rusch ◽  
R. A. Eatock
Keyword(s):  
Hair Cells ◽  
Time Course ◽  
Dissociation Constants ◽  
Resting Potential ◽  
Delayed Rectifier ◽  
Type I ◽  
Type Ii ◽  
Voltage Range ◽  
Average Maximum

1. Membrane currents of hair cells in acutely excised or cultured mouse utricles were recorded with the whole cell voltage-clamp method at temperatures between 23 and 36 degrees C. 2. Type I and II hair cells both had delayed rectifier conductances that activated positive to -55 mV. 3. Type I, but not type II, hair cells had an additional delayed rectifier conductance (gK,L) with an activation range that was unusually negative and variable. At 23-25 degrees C, V(1/2) values ranged from -88 to -62 mV in 57 cells. 4. gK,L was very large. At 23-25 degrees C, the average maximum chord conductance was 75 +/- 65 nS (mean +/- SD, n = 57; measured at -54 mV), or approximately 21 nS/pF of cell capacitance. 5. gK,L was highly selective for K+ over Na+ (permeability ratio PNa+/PK+:0.006), but unlike other delayed rectifiers, gK,L was significantly permeable to Cs+ (PCs+/PK+:0.31). gK,L was independent of extracellular Ca2+. 6. At -64 mV, Ba2+ and 4-aminopyridine blocked gK,L with apparent dissociation constants of 2.0 mM and 43 microM, respectively. Extracellular Cs+ (5 mM) blocked gK,L by 50% at -124 mV. Apamin (100 nM) and dendrotoxin (10 nM) has no effect. 7. The kinetic data of gK,L are consistent with a sequential gating model with at least two closed states and one open state. The slow activation kinetics (principal time constants at 23-25 degrees C:600-200 ms) had a thermal Q10 of 2.1. Inactivation (Q10:2.7) was partial at all temperatures. Deactivation followed a double-exponential time course and had a Q10 of 2.0. 8. At 23-25 degrees C, gK,L was appreciably activated at the mean resting potential of type I hair cells (-77 +/- 3.1 mV, n = 62), so that input conductances were often more than an order of magnitude larger than those of type II cells. If these conditions hold in vivo, type I cells would produce unusually small receptor potentials. Warming the cells to 36 degrees C produced parallel shifts in gK,L's activation range (0.8 +/- 0.3 mV/degrees C, n = 8), and in the resting potential (0.6 +/- 0.3 mV/degrees C, n = 4). Thus the high input conductances were not an artifact of unphysiological temperatures but remained high near body temperature. It remains possible that in vivo gK,L's activation range is less negative and input conductances are lower; the large variance in the voltage range of activation suggests that it may be subject to modulation.

scholarly journals Microfilament modification by dihydrocytochalasin B causes retinoic acid-modulated chondrocytes to reexpress the differentiated collagen phenotype without a change in shape.

1988 ◽  
Vol 106 (1) ◽  
pp. 161-170 ◽  
Author(s):  
P D Benya ◽  
P D Brown ◽  
S R Padilla
Keyword(s):  
Retinoic Acid ◽  
Cell Shape ◽  
Articular Chondrocytes ◽  
Type Ii Collagen ◽  
Phenotypic Change ◽  
Type Iii Collagen ◽  
Type I ◽  
Type Ii ◽  
The Stability ◽  
Rabbit Articular Chondrocytes

Primary monolayers of rabbit articular chondrocytes synthesize high levels of type II collagen and proteoglycan. This capacity was used as a marker for the expression of the differentiated phenotype. Such cells were treated with 1 microgram/ml retinoic acid (RA) for 10 d to produce a modulated collagen phenotype devoid of type II and consisting of predominantly type I trimer and type III collagen. After transfer to secondary culture in the presence of RA, the stability of the RA-modulated phenotype was investigated by culture in the absence of RA. Little reexpression of type II collagen synthesis occurred in this period unless cultures were treated with 3 X 10(-6) M dihydrocytochalasin B to modify microfilament structures. Reexpression of the differentiated phenotype began between days 6-8 and was essentially complete by day 14. Substantial reexpression occurred by day 8 without a detectable increase in cell rounding. Colony formation, characteristic of primary chondrocytes, was infrequent even after reexpression was complete. These data suggest that the integrity of microfilament cytoskeletal structures can be a source of regulatory signals that mechanistically appear to be more proximal to phenotypic change than the overt changes in cell shape that accompany reexpression of subculture-modulated chondrocytes in agarose culture.

scholarly journals Decoding the Structure of Non-Proteinogenic Amino Acids: The Rotational Spectrum of Jet-Cooled Laser-Ablated Thioproline

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7585
Author(s):  
Juan Carlos López ◽  
Alberto Macario ◽  
Andrés Verde ◽  
Alfonso Pérez-Encabo ◽  
Susana Blanco
Keyword(s):  
Interaction Analysis ◽  
Noncovalent Interaction ◽  
Coupling Constants ◽  
Cooh Group ◽  
Stable Form ◽  
Equatorial Position ◽  
Type I ◽  
Rotational Spectrum ◽  
Type Ii ◽  
The Stability

The broadband rotational spectrum of jet-cooled laser-ablated thioproline was recorded. Two conformers of this system were observed and identified with the help of DFT and ab initio computations by comparison of the observed and calculated rotational constants and 14N quadrupole coupling constants as well as the predicted energies compared to the observed relative populations. These conformers showed a mixed bent/twisted arrangement of the five-membered ring similar to that of the related compound thiazolidine with the N–H bond in axial configuration. The most stable form had the COOH group in an equatorial position on the same side of the ring as N-H. The arrangement of the C=O group close to the N-H bond led to a weak interaction between them (classified as type I) characterized by a noncovalent interaction analysis. The second form had a trans-COOH arrangement showing a type II O–H···N hydrogen bond. In thioproline, the stability of conformers of type I and type II was reversed with respect to proline. We show how the conformation of the ring depends on the function associated with the endocyclic N atom when comparing the structures of isolated thioproline with its zwitterion observed in condensed phases and with peptide forms.

scholarly journals A Predictive Classification of Charcot Arthropathy of Foot and Ankle

2020 ◽  
Vol 5 (4) ◽  
pp. 2473011420S0008
Author(s):  
Mohamed Abdelaziz Elghazy ◽  
Hani M. El-Mowafi ◽  
Ahmed El-Hawary ◽  
Yasser R. Kandil ◽  
Samer Ali ◽  
...  
Keyword(s):  
Complication Rate ◽  
Classification Systems ◽  
Type I ◽  
Type Ii ◽  
Foot And Ankle ◽  
Charcot Arthropathy ◽  
Lateral Column ◽  
Lisfranc Joints ◽  
The Stability

Category: Diabetes; Other Introduction/Purpose: Charcot arthropathy of foot and ankle is a devastating, chronic and progressive destruction of bone and joint integrity affecting one or more joints. It is commonly associated with diabetes mellitus and is characterized by joint subluxations, dislocation, and pathological fractures in patients with peripheral neuropathy and results in a debilitating deformity, possibly leading to ulceration and amputation.Many classification systems exist for charcot arthopathy of foot and ankle. However, there is still lack of consensus regarding best classification. We are proposing a new classification for charcot arthropathy of foot and ankle based on our experience of large cohort of charcot patients. Our classification can guide treatment and prognosis of diabetic charcot arthropathy of foot and ankle, which we are following for the last decade. Methods: Patients with post-acute charcot who presented at our institution from January 2004 to October 2019 were reviewed and were further classified anatomically into Type I and Type II based on plain radiographs. Type I was characterized by charcot affection of one region. Regions were categorized anatomically as a modification of both Brodsky and Schon classifications into: ankle, Lisfranc (tarsometatarsal), naviculocuneiform, forefoot, and hindfoot which includes one of the following: talonavicular joint, calcaneocuboid joint or calcaneus. Type II was characterized by affection of more than one region like peritalar, perinavicular, transverse tarsal or any other combination. Peritalar complex involves at least two joints of the following: ankle, subtalar, and talonavicular. The perinavicular type includes talonavicular and naviculocuniform or tarsometatarsal and naviculocuniform, while the transverse tarsal involves the calcaneocuboid and talonavicu-lar. Both types were further classified into four stages according to the stability, deformity and associated mechanical ulcers. (Table 1) Results: 235 patients (242 feet) were presented with diabetic charcot arthropathy. Mean age was 56 years (range 22-84). Follow- up ranged from 6 months to 10 years, with a mean of 3.3 years.Types IA and IIA were managed conservatively. All patients in Type IIB, IC, IIC, ID, IID and the majority of type IB received fusion surgery to achieve stability and correction of deformity. Stage IB ankle were fixed, while IB lisfranc were observed, and fixed if transformed to IC.Type II D had the highest complication rate in the form of: infection, nonunion, nail protrusion, implant failure, revision including exostectomy after full union and recurrence of ulcer in midfoot 3-4 years after surgery. Five patients ended up with amputation, and all were stage IID. Conclusion: For post-acute charcot, stage A have the best prognosis and can be managed conservatively provided good diabetes control.Type IB can be managed conservatively but when the ankle is affected in type IB, it is better to be elected for surgery. When charcot affects the Lisfranc joints, it is usually stable unless the lateral column is affected.All cases of type IIB, IC and IIC, ID, IID should receive surgery to achieve stability, correction of deformity and prevent complications.Mechanical ulcer (stage D) carries the worst prognosis and highest complication rate. Type IID might predict the risk of amputation [Table: see text]

Numerical Investigations of the Effect of Radial Power Distribution and Inlet Orifice on the Stability Behavior of Parallel Multichannel Type Natural Circulation Boiling Water Reactor

2018 ◽  
Vol 4 (3) ◽  
Author(s):  
Sapna Singh ◽  
Garima Singal ◽  
A. K. Nayak ◽  
Umasankari Kannan
Keyword(s):  
Low Power ◽  
Radial Direction ◽  
Natural Circulation ◽  
Boiling Water ◽  
Boiling Water Reactor ◽  
Type I ◽  
Type Ii ◽  
Water Reactor ◽  
The Core ◽  
The Stability

In a natural circulation boiling water reactor (BWR), the core power varies in both axial and radial directions inside the reactor core. The variation along the axial direction is more or less constant throughout the reactor; however, there exists variation of reactor power in the radial direction. The channels located at the periphery have low power compared to the center of the core and are equipped with orifices at their inlet. This creates nonuniformity in the radial direction in the core. This study has been performed in order to understand the effect of this radial variation of power on the stability characteristics of the reactor. Four channels of a pressure tube type natural circulation BWR have been considered. The reactor has been modeled using RELAP5/MOD3.2. Before using the model, it was first benchmarked with experimental measurements and then the characteristics of both low power and high power oscillations, respectively, known as type-I and type-II instability, have been investigated. It was observed that the type-I instability shows slight destabilizing effect of increase in power variation among different channels. However, in the case of type-II instability, it was found out that the oscillations get damped with an increase in power variation among the channels. A similar effect was found for the presence of orifices at the inlet in different channels. However, the increase in number of orificed channels showed stabilizing effect for both type-I and type-II instabilities.

scholarly journals A molecular dynamics investigation of CDK8/CycC and ligand binding: conformational flexibility and implication in drug discovery

2017 ◽  
Author(s):  
Wei Chen ◽  
Zhiye Tang ◽  
Tim Cholko ◽  
Chia-en A. Chang
Keyword(s):  
Molecular Dynamics ◽  
Drug Discovery ◽  
Ligand Binding ◽  
Md Simulations ◽  
Electrostatic Energy ◽  
Major Protein ◽  
Type I ◽  
Type Ii ◽  
Protein Motions ◽  
The Stability

AbstractThe activities of CDK8 with partner Cyclin C (CycC) are a common feature of many diseases, especially cancers. Here we report the study of dynamic behaviors and energy profiles of 13 CDK8/CycC systems, including the DMG-in and DMG-out conformations as well as 5 type I ligands and 5 type II ligands, with all-atom unbiased molecular dynamics (MD) simulations. We observed numerous regional motions within CDK8, which move in concert to form five major protein motions. The motion of the activation loop doesn’t appear to influence the binding of both types of ligands. Type I ligands remarkably reduce the motion of the C-terminal tail through the strong cation-π interaction between the ligands and ARG356, and type II ligands stabilize the αC helix by forming stable hydrogen bonds with GLU66. The MD calculations also confirmed the importance of CycC to the stability of the CDK8 system as well as the ligand binding. The MMPB/SA results show that van der Waals interaction is the main driving force for the binding of both types of ligands, but electrostatic energy and entropy penalty plays important roles in the binding of type II ligands. The volume analysis results indicate that the induced fitting theory applies in the binding of type I ligands. These results would help to improve the affinities of the existing ligands. Our MD work is complementary to crystal structures and may have implications in the development of new CDK8 inhibitors as well as in the field of drug discovery.

Studies on the Genetic Mutations of Hereditary Fibrinogen Disorder

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4954-4954
Author(s):  
Rong-Fu Zhou ◽  
Zhou Na ◽  
OuYang Jian
Keyword(s):  
De Novo ◽  
Conflicts Of Interest ◽  
Genetic Mutations ◽  
Heterozygous Mutation ◽  
Homologous Sequence ◽  
Type I ◽  
Type Ii ◽  
Restriction Digestion ◽  
Pcr Products ◽  
The Stability

Abstract Hereditary fibrinogen disorder is a rare kind of bleeding disease, which divided into two types. Type I is a kind of quantity disorder, including afibrinogenemia and hypofibrinogenemia. Type II is a kind of quality disorder, including dysfibrinogenemia. Fibrinogen is a kind of hexameric glycoprotein and consists of two pairs of three chains, which are Aα, Bβ and γchain. FGA、FGB and FGG code for the relevant glycoprotein. The mutations on these genes are responsible for this disorder. In this study, the levels of fibrinogen antigen of 12 cases with low fibrinogen activity were firstly detected. The results showed that one case had low level, and the patient definded as hypofibrinogenemia, and other 11 cases had normal level, thus these patients identified as dysfibrinogenemia. All exons and their flanks of FGA , FGB and FGG were amplified by PCR. THe PCR products were sequenced directly and blasted to normal sequence of corresponding gene to find the mutation. The result showed that among 11 cases with dysfibrinogenemia, five harbored Aα Arg16His heterozygous mutation and one of those also possessed a de novo γAsp185Asn heterozygous mutation ; one Aα Arg16Cys heterozygous mutation; four γArg275Cys heterozygous mutation and one γArg275His heterozygous mutation.The patient with hypofibrinogenemia harbored Aα Cys36Arg heterozygous mutation. Endonuclease restriction digestion was performed to exclude genetic polymorphism for the γAsp185Asn mutation. In molecular modeling, the hydrogen bonds were changed in the mutational variant of γ185Asn. Besides, a new site of glycosylation might appear after the mutation, which might lead to destroy the stability of molecular structure. The alignment of homologous sequence between different species suggested that γAsp185 was a highly conservative site. In a word, the above mutations might be the causes of dysfibrinogenemia or hypofibrinogenemia for these patients. Disclosures No relevant conflicts of interest to declare.

scholarly journals Structural Variations in the Complete Series of Lanthanoid Complexes of a Calix[4]arene Trisamide

2020 ◽  
Vol 73 (6) ◽  
pp. 424 ◽  
Author(s):  
Gareth L. Nealon ◽  
Matthew J. McIldowie ◽  
Brian W. Skelton ◽  
Mauro Mocerino ◽  
Massimiliano Massi ◽  
...  
Keyword(s):  
Solvent Molecule ◽  
Type I ◽  
Type Ii ◽  
Structural Variations ◽  
Type Iii ◽  
Structural Types ◽  
Complete Series ◽  
Transition Points ◽  
The Stability ◽  
Vacant Space

Lanthanoid picrate (pic) complexes of 5,11,17,23-tetra-tert-butyl-25-hydroxy-26,27,28-tris(diethylcarbamoylmethoxy)calix[4]arene (LH) have been synthesised and structurally characterised, to complete this series for all lanthanoids (other than promethium). From cerium to lutetium, three structural types are observed: Type I, [Ln(L)(O,O′-pic)](pic), Ln=Ce–Dy; Type II, [Ln(L)(O-pic)](pic), Ln=Tb, Ho; Type III, [Ln(L)(HOEt)](pic)2, Ln=Er–Lu. With lanthanum, three different ten-coordinate complexes were characterised; [Ln(L)(O,O′-pic)(HOEt)](pic), [Ln(L)(O,O′-pic)(OH2)](pic), and [Ln(L)(O,O′-pic)(HOMe)](pic). The crystallisation of Type I and II observed for terbium shows that the stability of the different structures are sensitively poised at the transition points. Nevertheless, the structures show that the vacant space in the coordination sphere left by the trisamide L tends to reduce across the series as expected. It is occupied by a bidentate picrate anion and unidentate solvent molecule with lanthanum, a bidentate picrate anion for cerium to dysprosium (Type I), a unidentate picrate anion for terbium and holmium (Type II), and finally a unidentate solvent molecule from erbium to lutetium (Type III). The coordination number thus reduces from 10 to 8 across the series.

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