Linear Increase In Intensity Research Articles

Novel approach for green synthesis of stable gold nanoparticles with dried turmeric root extract: investigations on sensor and catalytic applications.

In this study, we present the synthesis of gold nanoparticles (AuNPs) using a completely green synthesis method without the use of any additional functionalizing agent, except dried turmeric root extract. The significant synthesis parameters were optimized, and the applicability of AuNPs was investigated in areas such as plasmonic and fluorescent sensing of aluminum (Al3⁺) and chromium (Cr3⁺) ions, reduction of 4-nitrophenol (4-NP), and degradation of methylene blue (MB) and methyl orange (MO) dyes. Characterization studies were performed using UV-Vis spectroscopy, TEM, FTIR, and XRD, revealing that the AuNPs predominantly had a spherical morphology and a very small particle size of 8.5 nm, with stability maintained up to 120 days. The developed AuNP-based plasmonic sensors relied on aggregation-induced decreases in absorption, along with a red shift in the spectra. Fluorescence sensing demonstrated a linear increase in intensity with increasing concentrations of Al3⁺ and Cr3⁺, with detection limits of 0.83 and 1.19 nM, respectively. The catalytic activities of AuNPs were tested in reducing 4-NP and degradations of MB and MO dyes (binary system) in tap water and wastewater, with the reactions following pseudo-first-order kinetics. This study highlights the potential of AuNPs synthesized from turmeric roots for various environmental and sensing applications.

Electrospun Fibres of Chitosan/PVP for the Effective Chemotherapeutic Drug Delivery of 5-Fluorouracil

Electrospun nanofibrous mats consisting of chitosan (CS) and polyvinylpyrrolidone (PVP) were constructed. Tuning of solution and process parameters was performed and resulted in an electrospun system containing a 6:4 ratio of PVP:CS. This is a significant increase in the proportion of spun CS on the previously reported highest ratio PVP:CS blend. SEM analysis showed that the nanofibrous mats with 4 wt% CS/6 wt% PVP (sample E) comprised homogenous, uniform fibres with an average diameter of 0.569 μm. XPS analysis showed that the surface of the samples consisted of PVP. Raman and FTIR analysis revealed intermolecular interactions (via H-bonding) between PVP and CS. In FTIR spectra, the contribution of chitosan to CS/PVP complexes was shown by the downshift of the C=O band and by the linear increase in intensity of C-O stretching in CS. XPS analysis showed a smaller shift at the binding energy 531 eV, which relates to the amide of the acetylated functional groups. The obtained results demonstrate a sensitivity of Raman and FTIR tests to the presence of chitosan in PVP:CS blend. The chemotherapy drug 5-Fu was incorporated into the constructs and cell viability studies were performed. WST-8 viability assay showed that exposure of A549 human alveolar basal epithelial cells to 10 mg/mL 5-Fu loaded fibres was most effective at killing cells over 24 h. On the other hand, the constructs with loading of 1 mg/mL of drug were not efficient at killing A549 human alveolar basal epithelial cells. This study showed that CS/PVP/5-Fu constructs have potential in chemotherapeutic drug delivery systems.

The Far Side Opposite the Surgeon is Most Prone to Contamination From the C-Arm.

Fluoroscopy is used in many orthopaedic procedures. The C-Arm drape is known to be easily contaminated during orthogonal imaging. However, it is unknown if one area of the operative field is more prone to contamination than another. The purpose of this study was to determine if secondary transfer of contaminate from the undraped portion of the C-Arm occurs. A C-Arm was utilized with standardized draping in a simulated operating room. We used a simulated contaminant: a fluorescent powder that phosphoresces under ultraviolet light. The powder was placed over nonsterile portions. A darkened room with a black light, and a camera was used. C-Arm movements were simulated by cycling through lateral to Anteroposterior imaging. Images were taken before (control) and after cycles of orthogonal imaging. The change in light intensity was quantified at each time point over each area as a percentage of change. Contamination of the surgical field was observed in all areas after 15 cycles, with the area adjacent to the C-Arm being most pronounced. A linear increase in intensity with increased cycles was observed (R = 0.297; P = 0.036), with the mean increase in intensity of 5% after 15 cycles (95% confidence interval, 1.97-7.86). The remaining areas (closest to surgeon and middle) showed an increase as well but were not significant (P > 0.05). Secondary contamination of the surgical field from the C-Arm occurs. The area most prone to contamination is the area immediately adjacent to the fluoroscopy unit, usually opposite the surgeon.

Does Music-Based Cadence Entrainment Alter Metabolic Intensity?

The relationship between cadence (steps/min) and intensity (metabolic equivalents; METs) has been primarily established with controlled treadmill-based studies. It may be possible to use music to shape performance of overground walking cadence and thus prescribe intensity. PURPOSE: To evaluate overground walking cadence entrainment to music at different tempos (beats per min; BPM) and its ability to evoke intensity in a predictable manner. METHODS: Ten participants (6 men, 4 women; age 22.6±1.9 years, height 172.5±11.8 cm, weight 79.3±18.8 kg) completed six 5-minute walking trials around an oval track (40 m). During three trials, participants listened to a single song and matched their foot strikes to the beat of the music. The song tempo was modulated to 80, 100, and 125 BPM (randomized) using a commercially available app. Participants were outfitted with a portable indirect calorimeter to measure intensity (METs). Cadence during all trials was measured via direct observation (hand tally). Mean absolute percent error (MAPE) was calculated to compare the accuracy of participants’ entrainment (prescribed versus actual cadence). A simple linear regression model was used to evaluate the relationship between cadence and intensity. RESULTS: Participants successfully entrained to the cadences prescribed by the song tempo, especially at faster speeds (MAPE = 3.85±5.63, 3.12±2.88 and 2.63±2.31 for 80, 100 and 125 BPM, respectively). Increased music tempo was associated with a linear increase in intensity across all trials (y=0.16x - 2.14, r2=0.63, p<0.001). MET values for 80, 100 and 125 BPM were 3.23±0.44, 3.84±0.59, and 5.27±0.78, respectively. CONCLUSION: Participants successfully entrained to the modulated tempo of a single song, and faster music tempos elicited increased intensity. Based on these findings, music entrainment appears to be an effective method for evoking desired cadences during walking. The findings further suggest that music may be selected according to its potential to evoke specific intensities of ambulation. Future studies should examine the relationship between music entrainment and intensity with various song styles.

Preparation of γ‐aluminum oxynitride phosphor with Eu doping by direct nitridation in ammonia and postannealing

Abstractγ‐aluminum oxynitride (γ‐AlON) with spinel structure has attracted much attention for structural and functional application. γ‐AlON powders were successfully prepared by direct nitridation method of Al/Al(OH)3 starting mixture in ammonia and then calcined at high temperature. XRD, SEM, TEM, EDX, and photoluminescence were conducted to investigate the detail procedure and the optical properties of AlON: xEu phosphors. Nitrogen was introduced by the nitridation of metallic aluminum, appropriate Al amount and nitridation condition was necessary to obtain phase pure γ‐AlON. The as‐prepared AlON powders exhibited multifaceted grain morphology with fine particle size (1‐5 μm). Eu2O3 activator was reduced and transformed to EuAl12O19 by reaction with alumina, which remained in the product when x &gt; 0.25%. Under 331 nm excitation, AlON: xEu phosphors exhibited emission bands of 475 and 410 nm. 475 nm band reached a plateau at x = 0.25% due to the solubility of Eu2+ ion in AlON, whereas 410 nm band showed a linear increase in intensity with Eu2+ doping amount, which was believed to be the contribution of EuAl12O19. The present approach combination of direct nitridation in ammonia and postcalcination process showed potential application for AlON ceramic and AlON phosphors.

Impact of γ-Irradiation on the Kinetics of Laser Ablation of Polyamide Under Continuous CO2 Laser Beam

The effect of preliminary γ-irradiation on accelerating the speed of laser ablation of a polyamide is measured for the first time. A linear increase of intensity with a rate of 0.15 mg/s is observed during laser ablation of the polyamide pre-irradiated with γ-rays at a dose of 3,500 kGy. A γ-radiolysis dose of 10 – 20 kGy causes extreme changes in the molecular-topological parameters and the maximum level of growth of the rate of laser ablation. Thus pre-irradiation with γ-rays may be used to optimize the laser ablation of the polymer.

Detection and Live-Cell Imaging of a Micro-RNA Associated with the Cancer Neuroblastoma.

The ability of a molecular beacon to detect miR-132, a microRNA associated with the childhood cancer neuroblastoma, is reported in solution and within live cells. The stem-loop structure comprises a sequence complementary to miR-132, modified with a 6-FAM dye and dabcyl quencher on either end. In the absence of the target, self-binding occurs bringing the luminophore and quencher into close proximity, significantly decreasing the emission intensity. In the presence of miR-132, the signal is greatly enhanced, with a linear increase in intensity for mole ratios of beacon-to-target between 0.25 and 2.00. The structure differentiates between target and mismatched nucleic acid sequences, e.g., in the presence of a single-base mismatch, no increase in emission intensity beyond the background is observed. The stem-loop can be introduced into neuroblastoma cancer cells by electroporation, allowing miR-132 to be imaged within live cells. miR-132 appears to be localized within the nucleus of the cells, where its concentration is of the order of 1 μM. Significantly, transfection of the cells with a miR-132 mimic causes the emission intensity to more than double, demonstrating the sensitivity of the approach to changes in miR-132 concentration in live cells. This behavior opens up significant theranostic applications, such as the possibility of rapidly identifying retinoic acid resistant patients as well as providing a means to monitor therapeutic efficacy.

Carbon contamination and oxidation of Au surfaces under extreme ultraviolet radiation: An x-ray photoelectron spectroscopy study

Extreme ultraviolet (EUV) radiation-induced carbon contamination and oxidation of Au surfaces were investigated using x-ray photoelectron spectroscopy (XPS). The Au sample was irradiated by EUV radiation at 13.5 nm for 9 h, while a series of XPS spectra were recorded for monitoring chemical modification during EUV exposure. XPS analysis showed that total carbon contamination (C 1s peak) at the surface was increased by ∼14% after 9 h of EUV exposure, while the C–H component played a dominant role within the first 60 min of EUV irradiation, giving a sharp rise of the corresponding C 1s peak intensity, followed by a slow and linear increase in intensity of the C–C bonds. The later one represents an accumulation of carbon due to the EUV-assisted dissociation of residual hydrocarbons on Au surface. Oxide state of Au was also noticed to be formed during EUV irradiation, and was found to increase continuously before reaching its maximum followed by a progressive decay. The role of water dissociation in the presence of EUV radiation was discussed and correlated with Au oxidation phenomenon.

A Comparison of Traditional and Weekly Undulating Periodized Strength Training Programs With Total Volume and Intensity Equated

The purpose of this study was to compare the training adaptations attained during 12 weeks of traditional (TD) and weekly undulating (WUD) periodized strength training. Forty-two recreationally active men (age = 22 ± 2.3 years) were randomly assigned to 1 of 3 groups: control (C) (n = 14), TD (n = 14), or WUD (n = 14). Ten-repetition maximum (10RM) laboratory testing was carried out for the free weight back squat and the free weight flat bench press at baseline, week 8, and week 12. The subjects trained 3 d·wk (approximately 135 min·wk) from weeks 1 to 2 and 4 d·wk from week 3 to week 12 (approximately 180 min·wk). The TD and WUD groups trained using a periodized strength program with all program variables controlled (e.g., volume and intensity). The independent variable was the manipulation of intensity. The TD group used a linear increase in intensity, whereas the WUD group had a varied intensity. The results showed that both the TD and WUD groups made significant (p ≤ 0.05) increases in strength at weeks 8 and 12, but by week 12, the TD group was significantly (p ≤ 0.05) stronger than the WUD group. These results indicate that TD periodization with a linear increase in intensity was more effective at eliciting strength gains than WUD periodization with a varied intensity. The differences in strength gains between the TD and WUD groups may be related to extended periods of muscle soreness and fatigue that were present in the WUD group but not in the TD group. Thus, during long-term training, individuals may benefit more from TD periodized programs because there may be less muscle soreness and fatigue to disrupt practice and training.

Argon ions induced thermoluminescence properties of Ba 0.12Sr 0.88SO 4 phosphor

Thermoluminescence properties of barium strontium mixed sulfate have been studied by irradiation with Argon ions. The sample was recrystallized by chemical co-precipitation techniques using H 2SO 4. The X-ray diffraction study of prepared sample suggests the orthorhombic structure with average grain size of 60 nm. The samples were irradiated with 1.2 MeV Argon ions at fluences varying between 10 11 and 10 15 ions/cm 2. The argon ions penetrate to the depth of 1.89 μm and lose their energy mainly via electronic stopping. Due to ion irradiation, a large number of defects in the sample are formed. Thermally stimulated luminescence (TSL) glow curves of ion irradiated Ba 0.12Sr 0.88SO 4 phosphor exhibit broad peak with maximum intensity at 495 K composed of four overlapping peaks. This indicates that different sets of traps are being activated within the particular temperature range each with its own value of activation energy ( E) and frequency factor ( s). Thermoluminescence (TL) glow curves were recorded for each of the ion fluences. A linear increase in intensity of TL glow peaks was found with the increase in ion dose from 59 kGy to 5.9 MGy. The kinetic parameters associated with the prominent glow peaks were calculated using glow curve deconvolution (GCD), different glow curve shape and sample heating rate methods.

Sensitive Detection of KRAS Mutations in Archived Formalin-Fixed Paraffin-Embedded Tissue Using Mutant-Enriched PCR and Reverse-Hybridization

Recently, evidence has emerged indicating that assessment of KRAS mutations before anti-epidermal growth factor receptor therapy improves outcome in patients with metastatic colorectal cancer (CRC). We report here a novel reverse-hybridization (RH) assay to screen for KRAS mutations in formalin-fixed paraffin-embedded colorectal tissue samples. We combined mutant-enriched PCR based on peptide nucleic acid clamping and RH of amplification products to nitrocellulose test strips that contained a parallel array of oligonucleotide probes targeting 10 frequent mutations in codons 12 and 13 of the KRAS gene. DNA mixing experiments, which included eight different tumor cell lines with known KRAS mutations, were performed to examine the sensitivity of mutation detection. All KRAS mutations present in tumor cell lines were unambiguously identified by the RH assay with 1% of each cell line DNA diluted in normal DNA. RH was then used to screen for KRAS mutations in 74 colorectal tumor and 4 normal control samples. Twenty-six (35%) of the 74 tumor samples showed KRAS mutations. No mutation was found in the four samples of normal colorectal tissue. DNA sequencing without previous mutant enrichment, however, failed to detect four (15%) out of 26 KRAS-positive formalin-fixed paraffin-embedded samples (FFPE). This finding suggests that even after microdissection, mutant sequences in a given DNA isolate can be rare and more sensitive methods are needed for mutation analysis.

Solvation of benzene and phenyl halides in supercritical CO 2 studied by the interaction-induced CO 2 bending Raman band

To study solvation in supercritical (SC) CO 2, Raman spectra of SC CO 2 and its solutions with benzene or phenyl halides were studied based on the CO 2 bending vibrations, which become weakly Raman active upon interaction between CO 2 and other molecules. The bending band was as broad as 87 cm − 1 in neat SC CO 2 at 15 MPa. The addition of solute molecules resulted in steep decreases in band wavenumber and width in the region of solute molar fraction x < 0.03, and in an almost linear increase in intensity up to x of about 0.1. Solvation of the aromatic molecules in SC CO 2 was discussed based on preliminary ab initio calculations, which suggested that the CO 2 molecule interacts more strongly with the solute π-electrons than with the halogen substituent.

Transient diffusion of albumin in aortic walls: effects of binding to medial elastin layers

The goal of this study was to measure diffusive transport of albumin through artery walls experimentally and to analyze the results theoretically, taking into account the binding of albumin to elastic lamellae. Segments of rabbit aorta were placed in solutions of fluorescently labeled albumin for periods of 30, 60, 90, and 120 min, and the distributions of fluorescence intensity through the arterial media were observed. On average, intensity increased almost linearly with time. Bands of high intensity were observed corresponding to elastin layers within the media. The temporal and spatial variations of intensity were compared with predictions of theoretical models, including effects of albumin binding and hindered diffusion resulting from the complex wall structure. Based on these analyses, it was concluded that the spatial distribution of free albumin within the media equilibrated relatively rapidly, and that the observed linear increase in intensity reflected gradual accumulation of albumin bound to medial elastin layers. The results imply that previous theoretical analyses, in which binding was neglected, substantially underestimated albumin diffusivity in the aortic wall. With respect to stent-associated delivery of inhibitors of vascular cell proliferation, the results suggest that albumin might serve as an "affinity vehicle" for drug delivery to the aorta, by attaching the drug to an abundant component of the artery wall.

Sol–gel encapsulation of metalloproteins for the development of optical biosensors for nitrogen monoxide and carbon monoxide

Three heme proteins; horse heart cytochrome c, myoglobin (Mb) and hemoglobin (Hb), have been encapsulated in a sol–gel matrix and investigated for their potential use as biological recognition centres for the biosensing of NO and CO. It has been shown that the encapsulation of these metalloproteins in sol–gels has no effect on the formation of nitrosyl or carbonyl complexes as observed using UV/VIS spectrophotometry. The metalloproteins in sol–gels could be readily reduced to the FeII state, using excess sodium dithionite, and re-oxidized to the FeIII state on the addition of excess potassium ferricyanide. The observed redox capability within sol–gels enabled formation of the nitrosyl complex in both the FeIII and FeII states of Mb and Hb and in the FeIII state of cytochrome c. The formation of these nitrosyl complexes was shown to be reversible. Similarly, the reversible formation of the carbonyl complex with Mb and Hb in the reduced form has been achieved. Titration of a saturated solution of CO with Hb contained in a sol–gel showed a linear increase in intensity of the α(568 nm) and β(540 nm) absorption bands of the metalloprotein until saturation of the iron centres of the Hb occurred. A similar increase in intensity of the α(562 nm) absorption band of cytochrome c was observed when a saturated solution of NO was titrated against this metalloprotein contained in a sol–gel. The results show that sol–gels can be readily used as a host for the encapsulation of cytochrome c, Mb and Hb and that these metalloproteins can be used as the biological recognition centre for the biosensing of NO and CO at the micromolar level.

Analogous copper(I) coordination in metallothionein from yeast and the separate domains of the mammalian protein

The three-dimensional structures of both vertebrate Cu12-metallothionein (class 1) and yeast Cu8-thionein (class 2) are still unknown. The different copper:protein stoichiometry compared with that of the (ZnCd)7-metallothioneins was expected to alter the metal-thiolate cluster structure considerably. In order to avoid possible domain interactions in the hepatic rat metallothionein, separate chemically synthesized alpha- and beta-domains were used rather than the apoprotein. Apo yeast thionein, and the alpha- and beta-domains of rat liver metallothionein-2 were reconstituted by Cu(I) titration. Reconstitution steps were monitored using spectroscopic methods including luminescence emission and circular dichroism. Upon UV irradiation a linear increase in intensity of the orange-red luminescence was observed near 600 nm up to 6 Cu eq using either compound regardless of the different cysteine sulfer content (yeast thionein 12S, alpha-domain 11S, beta-domain 9S). The characteristic dichroic properties of the yeast copper-protein between 240 and 400 nm were in good agreement with those of the respective class 1 metallothionein domains. All observed Cotton bands were of similar shape and appeared in the same wavelength regions. However, the molar ellipticities were less pronounced in the alpha- and beta-fragments employed. There appears to be a striking similarity between the oligonuclear Cu(I) binding centers in all metallothionein species.