660 research outputs found
Localization of transversal cracks in sandwich beams and evaluation of their severity
An algorithm to assess transversal cracks in composite structures based on natural frequency changes due to damage is proposed. The damage assessment is performed in two steps; first the crack location is found, and afterwards an evaluation of its severity is performed. The technique is based on a mathematical relation that provides the exact solution for the frequency changes of bending vibration modes, considering two terms. The first term is related to the strain energy stored in the beam, while the second term considers the increase of flexibility due to damage. Thus, it is possible to separate the problems of localization and severity assessment, which makes the localization process independent of the beams cross-section shape and boundary conditions. In fact, the process consists of comparing vectors representing the measured frequency shifts with patterns constructed using the mode shape curvatures of the undamaged beam. Once the damage is localized, the evaluation of its severity is made taking into account the global rigidity reduction. The damage identification algorithm was validated by experiments performed on numerous sandwich panel specimens
Negative Correlation between Fetuin-A and Indices of Vascular Disease in Systemic Lupus Erythematosus Patients with and without Lupus Nephritis
Introduction: Fetuin-A, a systemic calcification inhibitor, has been negatively related to vascular calcification (VC) and cardiovascular mortality. In this study we investigated the association between fetuin-A levels and atherosclerotic vascular complications in systemic lupus erythematosus (SLE) patients with and without lupus nephritis (LN).
Methods: We recruited 20 SLE patients without LN, 20 SLE patients with LN and 20 healthy controls. We determined serum creatinine, lipid profile, high sensitivity C-reactive protein (hsCRP), calcium, phosphate and fetuin-A levels, and calculated the calcification risk index (CRI) and SLE disease activity index (SLEDAI) for all subjects. Vascular disease burden was assessed by quantification of carotid artery intima-media-thickness (IMT) and the ankle-brachial index (ABI).
Results: Fetuin-A levels were significantly lower in LN patients (0.47 ± 0.1 g/L) compared to SLE patients without LN (0.54 ± 0.1 g/L) and both were significantly lower than controls (0.78 ± 0.2 g/L). CRI was significantly higher in LN patients (89.1 ± 12.1 mg/L) compared to SLE patients without LN (67.2 ± 9.3 mg/L) and both were significantly higher than controls (34.2 ± 6.2 mg/L). Peripheral arterial disease (ABI < 0.9) was significantly more common in LN patients (55%) compared to SLE patients without LN (30%) as well as controls (0%). Fetuin-A levels showed significant negative correlations with serum creatinine, hsCRP, CRI, IMT and ABI in SLE patients with and without LN.
Conclusion: Fetuin-A levels were decreased in SLE patients with and without LN and negatively correlated with vascular complications. This suggests a potentially important role for fetuin-A deficiency as marker of vascular disease in SLE patients with and without LN.
Keywords: Atherosclerosis; Fetuin-A; Lupus nephritis; SLE; Vascular Calcification
Effects of Sub-lethal Lead Nitrate and Copper Sulfate Concentrations on Hematological Parameters During Long-term Exposure in Nile tilapia (Oreochromis niloticus)
437-441Nile tilapia (Oreochromis niloticus) weighing 51.66 ± 2.42 g were exposed to 0%, 20%, 40%, and 60% of LC50 to either lead nitrate (Pb(NO3)2) or copper sulfate (CuSO4) for 30 days. The Pb(NO3)2 and CuSO4 concentrations employed in the treatments of this study were 8.8, 17.6, and 26.4 mg/L and 2.57, 5.14, and 7.71 mg/l, respectively, and multiple hematological variables were evaluated. The red blood cell (RBC) count for the control group was 2.41 ± 0.13 while those of the treatment groups exposed to 8.8, 17.6, and 26.4 mg/L of Pb(NO3)2 were 2.21 ± 0.10, 1.94 ± 0.16, and 1.36 ± 0.10 × 106/µl, respectively, at the end of the study. Similarly, the hemoglobin (Hb), hematocrit (Hct), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), and platelet (PLT( levels significantly decreased as the Pb(NO3)2 concentration increased (p 4, showed decrease in the levels of RBC, Hb, Hct, WBC, and PLT when the concentration of CuSO4 increased, while the MCHC, MCH, and MCV levels significantly increased
HUWE1 cooperates with RAS activation to control leukemia cell proliferation and human hematopoietic stem cells differentiation fate
Acute myeloid leukemia (AML) is a poor prognosis hematopoietic malignance characterized by abnormal proliferation and differentiation of hematopoietic stem cells (HSCs). Although advances in treatment have greatly improved survival rates in young patients, in the elderly population, ~70% of patients present poor prognosis. A pan-cancer analysis on the TCGA cohort showed that AML has the second higher HUWE1 expression in tumor samples among all cancer types. In addition, pathway enrichment analysis pointed to RAS signaling cascade as one of the most important pathways associated to HUWE1 expression in this particular AML cohort. In silico analysis for biological processes enrichment also revealed that HUWE1 expression is correlated with 13 genes involved in myeloid differentiation. Therefore, to understand the role of HUWE1 in human hematopoietic stem and progenitor cells (HSPC) we constitutively expressed KRASG12V oncogene concomitantly to HUWE1 knockdown in stromal co-cultures. The results showed that, in the context of KRASG12V, HUWE1 significantly reduces cell cumulative growth and changes myeloid differentiation profile of HSPCs. Overall, these observations suggest that HUWE1 might contribute to leukemic cell proliferation and impact myeloid differentiation of human HSCs, thus providing new venues for RAS-driven leukemia targeted therapy approach
Preparation and in vivo evaluation of insulin-loaded biodegradable nanoparticles prepared from diblock copolymers of PLGA and PEG
The aim of this study was to design a controlled release vehicle for insulin to preserve its
stability and biological activity during fabrication and release. A modified, double emulsion,
solvent evaporation, technique using homogenisation force optimised entrapment efficiency of
insulin into biodegradable nanoparticles (NP) prepared from poly (dl-lactic-co-glycolic acid)
(PLGA) and its PEGylated diblock copolymers. Formulation parameters (type of polymer and
its concentration, stabiliser concentration and volume of internal aqueous phase) and
physicochemical characteristics (size, zeta potential, encapsulation efficiency, in vitro release
profiles and in vitro stability) were investigated. In vivo insulin sensitivity was tested by dietinduced
type II diabetic mice. Bioactivity of insulin was studied using Swiss TO mice with
streptozotocin-induced type I diabetic profile. Insulin-loaded NP were spherical and negatively
charged with an average diameter of 200–400 nm. Insulin encapsulation efficiency increased
significantly with increasing ratio of co-polymeric PEG. The internal aqueous phase volume
had a significant impact on encapsulation efficiency, initial burst release and NP size.
Optimised insulin NP formulated from 10% PEG-PLGA retained insulin integrity in vitro,
insulin sensitivity in vivo and induced a sustained hypoglycaemic effect from 3 hours to 6 days
in type I diabetic mice
Esculentin-2CHa-Related Peptides Modulate Islet Cell Function and Improve Glucose Tolerance in Mice with Diet-Induced Obesity and Insulin Resistance
The frog skin host-defense peptide esculentin-2CHa (GFSSIFRGVA10KFASKGLGK
D20LAKLGVDLVA30CKISKQC) displays antimicrobial, antitumor, and immunomodulatory
properties. This study investigated the antidiabetic actions of the peptide and selected analogues.
Esculentin-2CHa stimulated insulin secretion from rat BRIN-BD11 clonal pancreatic
β-cells at concentrations greater than 0.3 nM without cytotoxicity by a mechanism involving
membrane depolarization and increase of intracellular Ca2+. Insulinotropic activity was
attenuated by activation of KATP channels, inhibition of voltage-dependent Ca2+ channels
and chelation of extracellular Ca2+. The [L21K], [L24K], [D20K, D27K] and [C31S,C37S]
analogues were more potent but less effective than esculentin-2CHa whereas the [L28K]
and [C31K] analogues were both more potent and produced a significantly (P < 0.001)
greater maximum response. Acute administration of [L28K]esculentin-2CHa (75 nmol/kg
body weight) to high fat fed mice with obesity and insulin resistance enhanced glucose tolerance
and insulin secretion. Twice-daily administration of this dose of [L28K]esculentin-
2CHa for 28 days had no significant effect on body weight, food intake, indirect calorimetry
or body composition. However, mice exhibited decreased non-fasting plasma glucose
(P < 0.05), increased non-fasting plasma insulin (P < 0.05) as well as improved glucose tolerance
and insulin secretion (P < 0.01) following both oral and intraperitoneal glucose
loads. Impaired responses of isolated islets from high fat fed mice to established insulin
secretagogues were restored by [L28K]esculentin-2CHa treatment. Peptide treatment was
accompanied by significantly lower plasma and pancreatic glucagon levels and normalization
of α-cell mass. Circulating triglyceride concentrations were decreased but plasma cholesterol
and LDL concentrations were not significantly affected. The data encourage further
investigation of the potential of esculentin-2CHa related peptides for treatment of patients
with type 2 diabetes
Mutations in ASXL1 are associated with poor prognosis across the spectrum of malignant myeloid diseases
The ASXL1 gene is one of the most frequently mutated genes in malignant myeloid diseases. The ASXL1 protein belongs to protein complexes involved in the epigenetic regulation of gene expression. ASXL1 mutations are found in myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML) and acute myeloid leukemia (AML). They are generally associated with signs of aggressiveness and poor clinical outcome. Because of this, a systematic determination of ASXL1 mutational status in myeloid malignancies should help in prognosis assessment
In vitro and in vivo insulinotropic properties of the multifunctional frog skin peptide hymenochirin-1B: a structure–activity study
Hymenochirin-1b (Hym-1B; IKLSPETKDNLKKVLKGAIKGAIAVAKMV.NH2) is a cationic, α-helical amphibian host-defense peptide with antimicrobial, anticancer, and immunomodulatory properties. This study investigates the abilities of the peptide and nine analogues containing substitutions of Pro5, Glu6, and Asp9 by either l-lysine or d-lysine to stimulate insulin release in vitro using BRIN-BD11 clonal β cells or isolated mouse islets and in vivo using mice fed a high-fat diet to produce obesity and insulin resistance. Hym-1B produced a significant and concentration-dependent increase in the rate of insulin release from BRIN-BD11 cells without cytotoxicity at concentrations up to 1 µM with a threshold concentration of 1 nM. The threshold concentrations for the analogues were: [P5K], [E6K], [D9K], [P5K, E6K] and [E6K, D9k] 0.003 nM, [E6K, D9K] and [D9k] 0.01 nM, [P5K, D9K] 0.1 nM and [E6k] 0.3 nM. All peptides displayed cytotoxicity at concentrations ≥1 µM except the [P5K] and [D9k] analogues which were non-toxic at 3 µM. The potency and maximum rate of insulin release from mouse islets produced by the [P5K] peptide were significantly greater than produced by Hym-1B. Neither Hym-1B nor the [P5K] analogue at 1 µM concentration had an effect on membrane depolarization or intracellular Ca2+. The [P5K] analogue (1 µM) produced a significant increase in cAMP concentration in BRIN-BD11 cells and stimulated GLP-1 secretion from GLUTag cells. Down-regulation of the protein kinase A pathway by overnight incubation with forskolin completely abolished the insulin-releasing effects of [P5K]hym-1B. Intraperitoneal administration of the [P5K] and [D9k] analogues (75 nmol/kg body weight) to high-fat-fed mice with insulin resistance significantly enhanced glucose tolerance with a concomitant increase in insulin secretion. We conclude that [P5K]hym-1B and [D9k]hym-1B show potential for development into anti-diabetic agents
The future of enterprise groupware applications
This paper provides a review of groupware technology and products. The purpose of this review is to investigate the appropriateness of current groupware technology as the basis for future enterprise systems and evaluate its role in realising, the currently emerging, Virtual Enterprise model for business organisation. It also identifies in which way current technological phenomena will transform groupware technology and will drive the development of the enterprise systems of the future
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