Strain monitoring of tapestries: results of a three-year research project

The outcomes of an interdisciplinary research project between conservators and engineers investigating the strain experienced by different areas of a tapestry are described. Two techniques were used: full-field monitoring using digital image correlation (DIC) and point measurements using optical fibre sensors. Results showed that it is possible to quantify the global strain across a discrete area of a tapestry using DIC; optical fibre and other sensors were used to validate the DIC. Strain maps created by the DIC depict areas of high and low strain and can be overlaid on images of the tapestry, creating a useful visual tool for conservators, custodians and the general public. DIC identifies areas of high strain not obvious to the naked eye. The equipment can be used in situ in a historic house. In addition the work demonstrated the close relationship between relative humidity and strain

PHYTOCHEMICAL PROFILES, ANTIOXIDANT CAPACITY AND PROTECTIVE EFFECT AGAINST AAPH-INDUCED MOUSE ERYTHROCYTE DAMAGE BY DAPHNE GNIDIUM L. SHOOTS EXTRACTS

Objective: Various biological activities have been reported for Daphne gnidium, the aim of the present study was to determine polyphenols and some biological activities of extracts from the shoots of this plants.Methods: Phenolic and flavonoids contents of D. gnidium extracts (DGE) were determined by Folin-Ciocalteau and identified by HPLC–DAD/MS. Free radical scavenging and antioxidant potential of the crude (CE), chloroform (CHE) and ethyl acetate (EAE) extracts of D. gnidium shoots were investigated using several in vitro and ex vivo assays, including 2, 2-diphenyl-picrylhydrazyl radical scavenging, superoxide anion scavenging (by both enzymatic and nonenzymatic methods) and hydroxyl radical scavenging capacity methods. The antioxidant activity of the extracts was measured using the xanthine oxidase (XO) inhibitory activity, reducing power and ß-carotene-linoleic bleaching assays. Inhibition of lipid peroxidation and oxidative hemolysis were also performed to confirm the protective effect of these extracts.Results: It was found that values of phenolics varied between 130.84±5.99 and 137±7.66 mg gallic acid equivalent/g dry extract. HPLC analysis revealed the presence of cinnamic acid derivatives and other metabolites from the flavonoids family. All extracts exhibited a superoxide scavenging capacity. The EAE had the highest antioxidant activity as measured by DPPH radical and hydroxyl radical scavenging activity. The extracts showed an inhibitory effect on xanthine oxidase, the IC50 rangesfrom 0.021±0.001 to 0.061±0.001 mg/ml. The EAE showed also potent reducing power ability. CHE possess an inhibition ratio of (92.11%) in the linoleic acid oxidation assay close to that of BHT (96.77%). All extracts exhibited antioxidant activity in the linoleic acid emulsion system (3.87-61.11 %). Under the oxidative action of AAPH, EAE and CE showed higher protective effect against erythrocytes hemolysis than the CHE. The percentage of hemolysis (H%) determined for EAE and CE after 1 h of incubation were 0% and 1.9%, respectively.Conclusion: This study indicates that DGE contains relevant antioxidant compounds responsible, at least in part, for its antioxidant and radicals scavenging activity. Flavone derivatives were determined as the main active component of the shoots part and the CHE was the most active extract.Â

Amyloid β oligomers constrict human capillaries in Alzheimer's disease via signaling to pericytes

Cerebral blood flow is reduced early in Alzheimer’s disease (AD). Because most of the vascular resistance within the brain is in capillaries, this could reflect dysfunction of contractile pericytes on capillary walls. Here we used live and rapidly-fixed biopsied human tissue to establish disease-relevance, and rodent experiments to define mechanism. We found that, in humans with cognitive decline, amyloid β (Aβ) constricts brain capillaries at pericyte locations. This was caused by Aβ generating reactive oxygen species, which evoked the release of endothelin-1 (ET) that activated pericyte ETA receptors. Capillary, but not arteriole, constriction also occurred in vivo in a mouse model of AD. Thus, inhibiting the capillary constriction caused by Aβ could potentially reduce energy lack and neurodegeneration in AD

Preliminary Results on Asymptotic Stabilization of Hamiltonian Systems with Nonholonomic Constraints

This paper presents some preliminary results on asymptotic stabilization of nonholonomic mechanical systems using the Hamiltonian formulation proposed previously. Our work seeks to establish a general formulation for designing time-varying controllers for some mechanical system described in the generalized coordinates (position and momentum). The paper gives the change of coordinates that transforms the Hamiltonian system to the form needed to apply the center manifold theorem. We also present a worked example for which stability is analyzed.

Antimotility and andidiarrhoel activity of Myrtus communis L. Leaves essential oil in mice

Objective: To analyze the myrtle (Myrtus communis L.) leaves essential oil (MEO) and to investigate its antimotility and antidiahhroeal effects in mice. Methods: The chemical composition of the volatile fraction of myrtle was studied using GC-MS analysis. The antimotility activity was evaluated using normal gastric emptying and intestinal transit. The antidiarrhoeal and antisecretory activities of the essential oil were tested using castor oil methods in mice. Results: The results revealed that MEO characterized by its richness of α-pinene (54.1%) and 1.8-cineole (26.5%). MEO significantly decreased gastric emptying at the highest dose (500 mg/kg) and the intestinal transit at the three used doses (50, 250 and 500 mg/kg). The essential oil demonstrated also dose dependent antidiarrhoeal and antisecretory activities. Conclusion: MEO has antidiarrhoeal and antisecretory activity in mice, which may justify the use of this plant in traditional medicine for treatment of diarrhea and other gastrointestinal motility disorders

Kinetics of Inhibition of Xanthine Oxidase by Lycium arabicum and its Protective Effect against Oxonate- Induced Hyperuricemia and Renal Dysfunction in Mice

Purpose: To evaluate the in-vitro inhibition of xanthine oxidase (purified from bovine milk) by extracts of Lycium arabicum, as well as it is in vivo hypouricemic and renal protective effects.Methods: Four extracts of Lycium arabicum, methanol (CrE), chloroform (ChE), ethyl acetate (EaE) and aqueous (AqE) extracts, were screened for their total phenolics and potential inhibitory effects on purified bovine milk xanthine oxidase (XO) activity by measuring the formation of uric acid or superoxide radical. The mode of inhibition was investigated and compared with the standard drugs, allopurinol, quercitin and catechin. To evaluate their hypouricemic effect, the extracts were administered to potassium oxonate-induced hyperuricemic mice at a dose of 50 mg/kg body weight.Results: The results showed that EaE had the highest content of phenolic compounds and was the most potent inhibitor of uric acid formation (IC50 = 0.017 ± 0.001 mg/mL) and formation of superoxide (IC50 = 0.035 ± 0.001 mg/ml). Lineweaver-Burk analysis showed that CrE and EaE inhibited XO competitively, whereas the inhibitory activities exerted by ChE and AqE were of a mixed type. Intraperetoneal injection of L. arabicum extracts (50 mg/kg) elicited hypouricemic actions in hyperuricemic mice. Hyperuricemic mice presented a serum uric acid concentration of 4.71 ± 0.29 mg/L but this was reduced to 1.78 ± 0.11 mg/L by EaE, which was the most potent hyporuricemic extract.Conclusion: L. arabicum fractions have a strong inhibitory effect on xanthine oxidase and and also have a significantly lowering effect on serum and liver creatinine and urea levels in hyperuricemic mice.Keywords: Lycium arabicum, Uric acid, Creatinine, Superoxide, Phenolic compounds, Flavonoids, Hyperuricemi

Astrocytes contribute to the cerebral blood flow response to hypercapnia

Although astrocyte [Ca2+]i transients can evoke cerebral blood flow (CBF) changes, their role in CBF regulation has been questioned. Based on the signalling pathways which occur within astrocytes, we investigated whether astrocytes contribute to hypercapnia-evoked CBF responses.</p