31 research outputs found
Judd-Ofelt Analysis of Eu3+ Emission in TiO2 Anatase Nanoparticles
Preparation and spectroscopic studies of the TiO2 nanopowders doped with Eu3+ ions are described. Efficient emission in the red part of the visible spectrum can be obtained due to the D-5(0) - GT F-7(2) emission of europium ions. Quantum efficiency of such emission was estimated to be about 0.83, which indicates a rather weak role of the non-radiative losses. However, the increase of Eu3+ concentration up to 10 at% significantly lowers the quantum efficiency because of the energy transfer and re-absorption processes. Higher doping concentrations (larger than 3 at% of Eu3+) also decrease the covalency of the Eu3+-O2- chemical bonds.2nd International Symposium on Nano Materials, Technology and Applications (NANOMATA), Oct 15-17, 2014, Hanoi, Vietna
Towards Flexible and Cognitive Production—Addressing the Production Challenges
Globalization in the field of industry is fostering the need for cognitive production systems. To implement modern concepts that enable tools and systems for such a cognitive production system, several challenges on the shop floor level must first be resolved. This paper discusses the implementation of selected cognitive technologies on a real industrial case-study of a construction machine manufacturer. The partner company works on the concept of mass customization but utilizes manual labour for the high-variety assembly stations or lines. Sensing and guidance devices are used to provide information to the worker and also retrieve and monitor the working, with respecting data privacy policies. Next, a specified process of data contextualization, visual analytics, and causal discovery is used to extract useful information from the retrieved data via sensors. Communications and safety systems are explained further to complete the loop of implementation of cognitive entities on a manual assembly line. This deepened involvement of cognitive technologies are human-centered, rather than automated systems. The explained cognitive technologies enhance human interaction with the processes and ease the production methods. These concepts form a quintessential vision for an effective assembly line. This paper revolutionizes the existing industry 4.0 with an even-intensified human–machine interaction and moving towards cognitivity
The impact of different extracts of six Lamiaceae species on deleterious effects of oxidative stress assessed in acellular, prokaryotic and eukaryotic models in vitro
The main objective of this research was to evaluate the impact of methanolic, ethanolic and aqueous extracts of Origanum majorana L., Origanum vulgare L., Teucrium chamaedrys L., Teucrium montanum L., Thymus serpyllum L. and Thymus vulgaris L. (Lamiaceae) on the effects of free radicals using different model systems. The extracts were characterized on the basis of the contents of total phenolics, phenolic acids, flavonoids and flavonols, and also using high-performance liquid chromatography with diode-array detection. Antioxidant activity in vitro was assessed using DPPH assay. The genoprotective properties were tested using plasmid relaxation assay on pUC19 E. coli XL1-Blue, while SOS/umuC assay on Salmonella typhimurium TA1535/pSK1002 and Comet assay on human lung fibroblasts were used to assess the antigenotoxicity of the extracts. Ethanolic extracts had the most phenolics (up to 236.20 mg GAE/g at 0.5 mg/mL), flavonoids (up to 42.47 mg QE/g at 0.5 mg/mL) and flavonols (up to 16.56 mg QE/g at 0.5 mg/mL), and they exhibited the highest DPPH activity (up to 92.16% at 0.25 mg/mL). Interestingly enough, aqueous extracts provided the best protection of plasmid DNA (the lowest IC50 value was 0.17 mg/mL). Methanolic extracts, on the other hand, most efficiently protected the prokaryotic DNA, while all the extracts had a significant impact against genomic damages inflicted on human fibroblasts. O. vulgare extracts are considered to be the most promising in preserving the overall DNA integrity against oxidative genomic damages. Moreover, HPLC-DAD analysis highlighted rosmarinic acid as the most abundant in the investigated samples (551.45 mg/mL in total in all the extracts), followed by luteolin-7-O-glucoside (150.19 mg/mL in total), while their presence correlates with most of the displayed activities. The novelty of this study is reflected in the application of a prokaryotic model for testing the antigenotoxic effects of Lamiaceae species, as no previous reports have yet been published on the genoprotective potential of these species
Tobacco Smoke Mediated Induction of Sinonasal Microbial Biofilms
Cigarette smokers and those exposed to second hand smoke are more susceptible to life threatening infection than non-smokers. While much is known about the devastating effect tobacco exposure has on the human body, less is known about the effect of tobacco smoke on the commensal and commonly found pathogenic bacteria of the human respiratory tract, or human respiratory tract microbiome. Chronic rhinosinusitis (CRS) is a common medical complaint, affecting 16% of the US population with an estimated aggregated cost of $6 billion annually. Epidemiologic studies demonstrate a correlation between tobacco smoke exposure and rhinosinusitis. Although a common cause of CRS has not been defined, bacterial presence within the nasal and paranasal sinuses is assumed to be contributory. Here we demonstrate that repetitive tobacco smoke exposure induces biofilm formation in a diverse set of bacteria isolated from the sinonasal cavities of patients with CRS. Additionally, bacteria isolated from patients with tobacco smoke exposure demonstrate robust in vitro biofilm formation when challenged with tobacco smoke compared to those isolated from smoke naïve patients. Lastly, bacteria from smoke exposed patients can revert to a non-biofilm phenotype when grown in the absence of tobacco smoke. These observations support the hypothesis that tobacco exposure induces sinonasal biofilm formation, thereby contributing to the conversion of a transient and medically treatable infection to a persistent and therapeutically recalcitrant condition
Pediatric siMS score: A new, simple and accurate continuous metabolic syndrome score for everyday use in pediatrics
Background: The dichotomous nature of the current definition of metabolic syndrome (MS) in youth results in loss of information. On the other hand, the calculation of continuous MS scores using standardized residuals in linear regression (Z scores) or factor scores of principal component analysis (PCA) is highly impractical for clinical use. Recently, a novel, easily calculated continuous MS score called siMS score was developed based on the IDF MS criteria for the adult population. Objective: To develop a Pediatric siMS score (PsiMS), a modified continuous MS score for use in the obese youth, based on the original siMS score, while keeping the score as simple as possible and retaining high correlation with more complex scores. Subjects and methods The database consisted of clinical data on 153 obese (BMI ≥95th percentile) children and adolescents. Continuous MS scores were calculated using Z scores and PCA, as well as the original siMS score. Four variants of PsiMS score were developed in accordance with IDF criteria for MS in youth and correlation of these scores with PCA and Z score derived MS continuous scores was assessed. Results: PsiMS score calculated using formula: (2xWaist/Height) + (Glucose(mmol/l)/5.6) + (triglycerides(mmol/l)/1.7) + (Systolic BP/130)—(HDL(mmol/l)/1.02) showed the highest correlation with most of the complex continuous scores (0.792–0.901). The original siMS score also showed high correlation with continuous MS scores. Conclusion: PsiMS score represents a practical and accurate score for the evaluation of MS in the obese youth. The original siMS score should be used when evaluating large cohorts consisting of both adults and children
Judd–Ofelt Analysis of Eu<sup>3+</sup> Emission in TiO<sub>2</sub> Anatase Nanoparticles
Određivanje linurona u kamilici LC-MS/MS tehnikom i QuEChERS metodom ekstrakcije
Linuron is a selective herbicide used for the control of broadleaf weeds. Its mode of action is
the inhibition of photosynthesis. The QuEChERS method for extraction of linuron residues from
chamomile was used. The LC–MS/MS method was used for determination of linuron residues. Its
linearity was studied in a range of 0.025-0.50 μg/ml using matrix-matched calibration, and the
determination coefficient (R2) was higher than 0.99. Blank chamomile samples were spiked with
linuron solution at three concentration levels yielding recoveries of over 90%. The internal standard
added in all samples was isoproturon–d6. There were no linuron residues in chamomile flowers,
while the residues ranged from 0.010 to 0.040 mg/kg in the flower stalk samples.Linuron je selektivni herbicid, koji se koristi za suzbijanje širokolisnih korova. Njegov
mehanizam delovanja je inhibicija fotosinteze (fotosistema II). Za ekstrakciju ostataka linurona
iz uzoraka kamilice korišćena je QuEChERS metoda. Određivanje nivoa ostataka linurona
vršeno je tečnom hromatografijom sa masenim spektroskopijom. Linearnost metode je
ispitivana u opsegu koncentracija od 0.025 – 0.50 μg/ml, korišćenjem metode kalibracije u
matriksu, pri čemu je koeficijent određivanja (R2) bio veći od 0.99. Tačnost metode je ispitivana
obogaćivanjem kontrolnih uzoraka kamilice na tri koncentraciona nivoa. Prinos ekstrakcije je
bio preko 90 %. Interni standard korišćen za analizu je bio izoproturon-D6. U cvetu kamilice
nisu nađeni ostaci linurona, dok su u uzorcima drške bili u opsegu od 0.010-0.040 mg/kg
Thermal Properties of PMMA/TiO2 Nanocomposites Prepared by In-Situ Bulk Polymerization
The surface of anatase TiO2 nanoparticles, obtained by the controlled hydrolysis of titanium tetrachloride, was modified by 6-palmitate ascorbic acid. The surface modified TiO2 nanoparticles were dispersed in methyl methacrylate and mixed with a appropriate amount of poly(methyl methacrylate) to obtain a syrup. The nano-composite sheets were made by bulk polymerization of the syrup in a glass sandwich cell using 2,2-azobisisobutyronitrile as initiator. The molar masses and molar mass distributions of synthesized poly(methyl methacrylate) samples were determined by gel permeation chromatography. The content of unreacted double bonds in synthesized samples was determined by H-1 NMR spectroscopy. The influence of TiO2 nanoparticles on the thermal stability of the poly(methyl methacrylate) matrix was investigated using thermogravimetric analysis and differential scanning calorimetry. The synthesized samples of poly(methyl methacrylate) have different molar mass and polydispersity depending on the content of the surface modified TiO2 nanoparticles. The values of glass transition temperature of so prepared nanocomposite samples were lower than for pure poly(methyl methacrylate), while the glass transition temperature of samples preheated in inert atmosphere was very similar to the glass transition temperature of pure poly(methyl methacrylate). The thermal stability of nanocomposite samples in nitrogen and air was different from thermal stability of pure poly(methyl methacrylate). POLYM. COMPOS., 30:737-742, 2009. (C) 2008 Society of Plastics Engineer
Connexin 37, 40, 43 and Pannexin 1 Expression in the Gastric Mucosa of Patients with Systemic Sclerosis
Systemic sclerosis (SSc) is an autoimmune disease characterized by fibrosis of the skin and internal organs. Although its pathogenesis is not fully understood, connexins (Cxs) and pannexins (Panx) could be involved in the process of fibrosis. We analyzed the protein expression of Cx37, Cx40, Cx43, and Panx1 in the gastric mucosa of patients with SSc and healthy volunteers, using immunofluorescence staining. Protein levels of Cx37 were slightly increased, while the levels of Cx40 were significantly decreased in the lamina propria of the gastric mucosa of SSc patients compared to the controls. The changes were proportional to SSc severity, with the most prominent changes found in patients with severe diffuse cutaneous SSc. No differences in Cx43 or Panx1 levels were found between the analyzed groups of samples. The lack of changes in Cx43 expression, which has been previously associated with fibrosis, could be due to the weak expression of Cx43 in the gastric mucosa in general. Further studies on full-thickness gastric biopsies containing muscle layers and animal SSc models are needed to fully elucidate the role of Cxs and Panxs in SSc-associated fibrosis