Crystallographic and transport studies on AsF5 intercalated graphite from 4.2 to 295 K. II. Effects of structural transformations and demixing on basal plane and c-axis electrical resistivity

Part I of this study has shown that first stage AsF5 intercalated graphite samples can be classified into two types of compounds, depending upon the nature of the structural modifications they undergo upon lowering the temperature from 295 to 4.2 K. These structural changes are related to demixing of the species contained within the intercalate resulting in the formation of phases rich in AsF5, AsF−6 − AsF5, or AsF3 depending on the degree to which the AsF5 has been converted into AsF−6 and AsF3. Resistivity studies have been carried out in the basal plane [ρa (T)] and along the c axis [ρc (T)]. The type 1 compounds, in which the AsF5 has undergone little conversion, manifest a ρa (T) transition related to the incommensurate-to-commensurate (I⇉C) transformation of the AsF5 in-plane unit cell and a rapid, structureless 300 to 200 K decrease in ρc (T). The type 2 compounds involving a greater degree of conversion of AsF5 into AsF3 and AsF6 yield more complex ρc (T) behavior from 300 to 200 K attributed to the more involved ordering phenomena; no anomalies are seen in ρa (T). In the case of the stage 2 compounds, changes in ρc (T) are seen down to lower temperatures in accord with structural data indicating a downshift of the I⇉C transformation by ∼ 70 K. The transport results are discussed in the light of the crystallographic data and the low-temperature results are analyzed within the framework of proposed conductivity models.

Download Full-text

Ultra- and micro-structural changes of respiratory tracts in SARS-CoV-2 infected Syrian hamsters

Veterinary Research ◽

10.1186/s13567-021-00988-w ◽

2021 ◽

Vol 52 (1) ◽

Author(s):

Myeon-Sik Yang ◽

Byung Kwan Oh ◽

Daram Yang ◽

Eun Young Oh ◽

Yeonhwa Kim ◽

...

Keyword(s):

Structural Changes ◽

Alveolar Epithelium ◽

Inflammatory Cells ◽

Alveolar Wall ◽

Lamellar Bodies ◽

Electron Microscopic ◽

Syrian Hamsters ◽

Electron Lucent

AbstractThe severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) pandemic is causing a global crisis. It is still unresolved. Although many therapies and vaccines are being studied, they are still in their infancy. As this pandemic continues, rapid and accurate research for the development of therapies and vaccines is needed. Therefore, it is necessary to understand characteristics of diseases caused by SARS-CoV-2 through animal models. Syrian hamsters are known to be susceptible to SARS-CoV-2. They were intranasally inoculated with SARS-CoV-2. At 2, 4, 8, 12, and 16 days post-infection (dpi), these hamsters were euthanized, and tissues were collected for ultrastructural and microstructural examinations. Microscopic lesions were prominent in the upper and lower respiratory tracts from 2 and 4 dpi groups, respectively. The respiratory epithelium in the trachea, bronchiole, and alveolar showed pathological changes. Inflammatory cells including neutrophils, lymphocytes, macrophages, and eosinophils were infiltrated in/around tracheal lamina propria, pulmonary vessels, alveoli, and bronchiole. In pulmonary lesions, alveolar wall was thickened with infiltrated inflammatory cells, mainly neutrophils and macrophages. In the trachea, epithelial damages started from 2 dpi and recovered from 8 dpi, consistent with microscopic results, High levels of SARS-CoV-2 nucleoprotein were detected at 2 dpi and 4 dpi. In the lung, lesions were most severe at 8 dpi. Meanwhile, high levels of SARS-CoV-2 were detected at 4 dpi. Electron microscopic examinations revealed cellular changes in the trachea epithelium and alveolar epithelium such as vacuolation, sparse micro-organelle, and poor cellular margin. In the trachea epithelium, the number of cytoplasmic organelles was diminished, and small vesicles were prominent from 2 dpi. Some of these electron-lucent vesicles were filled with virion particles. From 8 dpi, the trachea epithelium started to recover. Because of shrunken nucleus and swollen cytoplasm, the N/C ratio of type 2 pneumocyte decreased at 8 and 12 dpi. From 8 dpi, lamellar bodies on type 2 pneumocyte cytoplasm were increasingly observed. Their number then decreased from 16 dpi. However, there was no significant change in type 1 pneumocyte. Viral vesicles were only observed in the cytoplasm of type 2 pneumocyte. In conclusion, ultra- and micro-structural changes presented in this study may provide useful information for SARS-CoV-2 studies in various fields.

Download Full-text

Inhibitory effect of okadaic acid derivatives on protein phosphatases. A study on structure-affinity relationship

Biochemical Journal ◽

10.1042/bj2840539 ◽

1992 ◽

Vol 284 (2) ◽

pp. 539-544 ◽

Cited By ~ 129

Author(s):

A Takai ◽

M Murata ◽

K Torigoe ◽

M Isobe ◽

G Mieskes ◽

...

Keyword(s):

Okadaic Acid ◽

Structural Changes ◽

Protein Phosphatases ◽

Inhibitory Effect ◽

Chemical Processes ◽

Hydroxyl Group ◽

Confidence Limits ◽

X Ray ◽

Structural Modifications

The effect of structural modifications of okadaic acid (OA), a polyether C38 fatty acid, was studied on its inhibitory activity toward type 1 and type 2A protein phosphatases (PP1 and PP2A) by using OA derivatives obtained either by isolation from natural sources or by chemical processes. The dissociation constant (Ki) for the interaction of OA with PP2A was estimated to be 30 (26-33) nM [median (95% confidence limits)]. The OA derivatives used and their affinity for PP2A, expressed as Ki (in brackets) were as follows: 35-methyl-OA (DTX1) [19 (12-25) pM], OA-9,10-episulphide (acanthifolicin) [47 (25-60) pM], 7-deoxy-OA [69 (31-138) pM], 14,15-dihydro-OA [315 (275-360) pM], 2-deoxy-OA [899 (763-1044) pM], 7-O-palmitoyl-OA [greater than 100 nM], 7-O-palmitoyl-DTX1 [greater than 100 nM], methyl okadate [much greater than 100 nM], 2-oxo-decarboxy-OA [much greater than 100 nM] and the C-15-C-38 fragment of OA [much greater than 100 nM]. The sequence of the affinity of these derivatives for PP1 was essentially the same as that observed with PP2A, although the absolute values of Ki were very different for the enzymes. The inhibitory effect of OA on PP2A was reversed by applying a murine monoclonal antibody against OA, which recognizes modifications of the 7-hydroxyl group of the OA molecule. It has been shown by n.m.r. spectroscopy and X-ray analysis that one end (C-1-C-24) of the OA molecule assumes a circular conformation. The present results suggest the importance of the conformation for the inhibitory action of OA on the protein phosphatases. The ratios of the Ki values for PP1 to that for PP2A, which were within the range 10(3)-10(4), tended to be smaller for the derivatives with lower affinity, indicating that the structural changes in OA impaired the affinity for PP2A more strongly than that for PP1.

Download Full-text

Structural changes associated with solid-state reactions in Al–Ag–Mg alloys

Journal of Applied Crystallography ◽

10.1107/s0021889886089707 ◽

1986 ◽

Vol 19 (3) ◽

pp. 174-180 ◽

Cited By ~ 14

Author(s):

S. M. Cousland ◽

G. R. Tate

Keyword(s):

Structural Changes ◽

Mg Alloys ◽

Mg Alloy ◽

Solid State Reactions ◽

Phase Volume ◽

Alloy Type ◽

Equilibrium Phases ◽

Precipitated Phases

The structural changes associated with the precipitation of metastable and equilibrium phases during decomposition of three supersaturated Al-rich Al–Ag–Mg alloys at 393, 456 and 508 K have been established by analysing the diffraction of monochromatic X-radiation by single-crystal alloy plates. Precipitated phases observed were: (a) in the Al–0.54 at.% Ag–4.49 at.% Mg alloy, type 1 Guinier–Preston zones, T′ phase, T phase; (b) in the Al–0.87 at.% Ag–1.80 at.% Mg alloy, type 1 Guinier–Preston zones, type 2 Guinier–Preston zones (a newly observed body-centred tetragonal compound, a = 4.13, c = 8.60 Å, space group I 41/amd), T′ phase, η phase; (c) in the Al–1.30 at.% Ag–1.05 at.% Mg alloy, type 1 Guinier–Preston zones, type 2 Guinier–Preston zones, γ phase. Volume fractions of the precipitated phases, sizes of the precipitates and orientations of cell axes relative to the axes of the Al lattice are given for various stages of each decomposition sequence.

Download Full-text

Renal structure in type 2 diabetes: facts and misconceptions

Journal of Nephrology ◽

10.1007/s40620-020-00797-y ◽

2020 ◽

Vol 33 (5) ◽

pp. 901-907 ◽

Cited By ~ 1

Author(s):

Angelo Di Vincenzo ◽

Silvia Bettini ◽

Lucia Russo ◽

Sara Mazzocut ◽

Michael Mauer ◽

...

Keyword(s):

Type 2 Diabetes ◽

Diabetic Nephropathy ◽

Structural Changes ◽

Clinical Manifestations ◽

Renal Diseases ◽

Diabetic Patients ◽

Renal Lesion ◽

Renal Lesions

Abstract The clinical manifestations of diabetic nephropathy are similar in type 1 and type 2 diabetes, while the renal lesions may differ. Indeed, diabetic glomerulopathy is the predominant renal lesion in type 1 diabetes, although also tubular, interstitial and arteriolar lesions are present in the advanced stages of renal disease. In contrast, in type 2 diabetes renal lesions are heterogeneous, and a substantial number of type 2 diabetic patients with diabetic kidney disease have mild or absent glomerulopathy with tubulointerstitial and/or arteriolar abnormalities. In addition, a high prevalence of non-diabetic renal diseases, isolated or superimposed on classic diabetic nephropathy lesions have been reported in patients with type 2 diabetes, often reflecting the bias of selecting patients for unusual clinical presentations for renal biopsy. This review focuses on renal structural changes in type 2 diabetes, emphasizing the contribution of research kidney biopsy studies to the understanding of the pathogenesis of DKD and of the structural lesions responsible for the different clinical phenotypes. Also, kidney biopsies could provide relevant information in terms of renal prognosis, and help to understand the different responses to different therapies, especially SGLT2 inhibitors, thus allowing personalized medicine.

Download Full-text

Pathogenesis: Structural Changes in the Kidneys in Type 1 and Type 2 Diabetes

Diabetes and Kidney Disease ◽

10.1007/978-3-030-86020-2_6 ◽

2022 ◽

pp. 105-154

Author(s):

Guillermo A. Herrera ◽

Luis del Pozo-Yauner ◽

Jeffrey J. Aufman ◽

Elba A. Turbat-Herrera

Keyword(s):

Type 2 Diabetes ◽

Structural Changes

Download Full-text

Structural tendon changes in patients with acromegaly: assessment of Achilles tendon with sonoelastography.

Medical Ultrasonography ◽

10.11152/mu.2013.2066.181.edo ◽

2016 ◽

Vol 18 (1) ◽

pp. 30 ◽

Cited By ~ 4

Author(s):

Eda Demir Onal ◽

Ali Ipek ◽

Berna Evranos ◽

Ilkay Sedakat Idilman ◽

Bekir Cakir ◽

...

Keyword(s):

Achilles Tendon ◽

Structural Changes ◽

Serum Levels ◽

Inactive Disease ◽

Blood Concentrations ◽

Igf I ◽

Different Types ◽

The Mean

Aims: To describe the sonoelastographic appearance of the Achilles tendon in acromegalic patients and to determine whether the blood concentrations of growth hormone (GH) and insulin-like growth factor (IGF-1) are associated with the various sonographic elasticity types of Achilles tendons. Material and methods: Eighty-four Achilles tendons of 42 acromegaly patients and 84 Achilles tendons of 42 healthy volunteers were assessed with sonoelastography. The tendons were classified into two main types according to the elasticity features: type 1 blue/green (hard tissue) and type 2 yellow/red within green (intermediate–soft tissue). Two subtypes of these types were also defined. According to the definition, the elasticity of the tissue was in a spectrum ranging from hard to soft as the type progressed from 1a to 2b. Results: The mean thickness of Achilles tendons in patients with acromegaly was significantly higher compared with healthy Achilles tendons (5.1±0.7 mm vs. 4.4±0.5, p<0.001), and patients with active disease had thicker Achilles tendons (5.5±0.8 mm vs. 4.8±0.5 mm in inactive disease, p=0.003). A significantly higher proportion of acromegaly patients had type 2 sonoelastographic appearance of the Achilles tendon (124/252 third; 49.2% vs. 81/252 third; 32.1%, p=0.0001). Activity status of acromegaly and GH/IGF-I levels were similar in patients with different types of elasticity (p>0.05). Conclusions: Sonoelastography revealed structural changes in the tendinous tissue of patients with acromegaly, but it was not sensitive enough to reflect changes in the serum levels of GH/IGF-1.

Download Full-text

Comparative study on the effects of type 1 and type 2 diabetes on structural changes and hormonal output of the adrenal cortex in male Wistar rats

Journal of Diabetes & Metabolic Disorders ◽

10.1186/2251-6581-12-9 ◽

2013 ◽

Vol 12 (1) ◽

Cited By ~ 13

Author(s):

Zohreh Elahi-Moghaddam ◽

Morteza Behnam-Rassouli ◽

Naser Mahdavi-Shahri ◽

Roya Hajinejad-Boshroue ◽

Elaheh Khajouee

Keyword(s):

Type 2 Diabetes ◽

Comparative Study ◽

Adrenal Cortex ◽

Wistar Rats ◽

Structural Changes ◽

Male Wistar Rats

Download Full-text

Osteoporosis Complicating Some Inborn or Acquired Diseases

Physiological Research ◽

10.33549/physiolres.934027 ◽

2018 ◽

pp. S441-S454 ◽

Cited By ~ 1

Author(s):

I. ZOFKOVA ◽

P. NEMCIKOVA

Keyword(s):

Chronic Diseases ◽

Metabolic Disorders ◽

Structural Changes ◽

Inflammatory Diseases ◽

Underlying Disease ◽

Cortical Porosity ◽

Mechanisms Of Development

Osteoporosis in chronic diseases is very frequent and pathogenetically varied. It complicates the course of the underlying disease by the occurrence of fractures, which aggravate the quality of life and increase the mortality of patients from the underlying disease. The secondary deterioration of bone quality in chronic diseases, such as diabetes of type 1 and type 2 and/or other endocrine and metabolic disorders, as well as inflammatory diseases, including rheumatoid arthritis – are mostly associated with structural changes to collagen, altered bone turnover, increased cortical porosity and damage to the trabecular and cortical microarchitecture. Mechanisms of development of osteoporosis in some inborn or acquired disorders are discussed.

Download Full-text