Decrement In Intensity Research Articles

H-Bonding of Furan and Its Hydrogenated Derivatives with the Isolated Hydroxyl of Amorphous Silica: An IR Spectroscopic and Thermodynamic Study

The interactions of furan and its hydrogenated derivatives (2,3-dihydrofuran, 2,5-dihydrofuran, tetrahydrofuran, and diethyl ether) with the isolated silanol groups at the surface of a highly dehydrated amorphous silica have been investigated by means of IR spectroscopy, at both constant and variable temperature. The adsorbate molecules studied form H-bonds of different strengths with surface silanols. With hydrogenated derivatives, the interaction involves the basic O atom, whereas with the aromatic furan molecule, the interaction probably occurs at the C═C double bond. The spectroscopic features of the stretching mode of H-bonded silanols change with the interacting molecule: classical correlations are observed. Because isolated silanols act as an ideal thermodynamic ensemble, the Langmuir model applies to all interactions. The fraction of silanols engaged in H-bonding can be measured from the decrement in intensity of the 3745 cm−1 band, so that corresponding optical isotherms can readily be drawn. The...

First detection of the Sunyaev Zel'dovich effect increment atλ< 650 μm

The Sunyaev-Zel'dovich (SZ) effect is a spectral distortion of the cosmic microwave background as observed through the hot plasma in galaxy clusters. This distortion is a decrement in the CMB intensity for lambda > 1.3 mm, an increment at shorter wavelengths, and small again by lambda ~250 um. As part of the Herschel Lensing Survey (HLS) we have mapped 1E0657-56 (the Bullet cluster) with SPIRE with bands centered at 250, 350 and 500 um and have detected the SZ effect at the two longest wavelengths. The measured SZ effect increment central intensities are Delta I_{0} = 0.097 +- 0.019 MJy sr^{-1} at 350 um and Delta I_{0} = 0.268 +- 0.031 MJy sr^{-1} at 500 um, consistent with the SZ effect spectrum derived from previous measurements at 2 mm. No other diffuse emission is detected. The presence of the finite temperature SZ effect correction is preferred by the SPIRE data at a significance of 2.1 sigma, opening the possibility that the relativistic SZ effect correction can be constrained by SPIRE in a sample of clusters. The results presented here have important ramifications for both sub-mm measurements of galaxy clusters and blank field surveys with SPIRE.

Dimensional error analysis in point cloud-based inspection using a non-contact method for data acquisition

The digital reconstruction of a computer aided design model from a physical object in the case of non-existence of such models has been a great challenge to engineers. With the advent of coordinate measuring machines (CMM), topological information of the points on the object's surface can be extracted in the form of a point cloud. However, CMM has been a very slow process with relatively low resolution which becomes a hurdle for a rapid manufacturing process. As a result, a non-contact method has been developed to provide higher speed and high resolution scanning. Therefore, the source of uncertainties for a non-contact probe, especially the laser scanner, had been reviewed to identify the potential improvement areas. Although the uncertainties are related to data acquisition capability, the surface construction effectiveness from the point clouds has similar importance to obtain the most accurate contour with minimum deviation from the actual surface. This can be achieved by eliminating the noise and by fitting the best shape according to the feature, such as a plane, cylinder or sphere, to the point cloud. The main aim of this work is to analyse and improve the performance of the laser scanner in terms of dimensional accuracy. A DIGIBOT II™ 3D laser digitizer which uses a remote ranging method was examined in the present work. The triangulation scanning system of this digitizer uses a high energy light source projected on the object's surface and a detector to sense the reflection. It was found that the scanning errors consist of random errors and systematic errors. For this scanner, the scanning data are random and follow the Gaussian distribution after the outliers are eliminated from the point cloud. The random error follows a systematic pattern where it varies with the scan depth and it is at a minimum when the y-coordinate is 228 mm and where the value of the error would be −0.0642 mm. The first systematic error is caused by the difference in the efficiency of photodetectors and the second systematic error is caused by the reflected laser intensity decrement as the scan depth increases. The second systematic error changes linearly when the y-coordinate is positive. Other methods for improving the scanning accuracy of the scanner have been recommended.

Effect of a chameleon scalar field on the cosmic microwave background

We show that a direct coupling between a chameleonlike scalar field and photons can give rise to a modified Sunyaev-Zel'dovich (SZ) effect in the cosmic microwave background (CMB). The coupling induces a mixing between chameleon particles and the CMB photons when they pass through the magnetic field of a galaxy cluster. Both the intensity and the polarization of the radiation are modified. The degree of modification depends strongly on the properties of the galaxy cluster such as magnetic field strength and electron number density. Existing SZ measurements of the Coma cluster enable us to place constraints on the photon-chameleon coupling. The constrained conversion probability in the cluster is ${\mathcal{P}}_{\mathrm{Coma}}(204\text{ }\text{ }\mathrm{GHz})<6.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ at 95% confidence, corresponding to an upper bound on the coupling strength of ${g}_{\mathrm{eff}}^{(\mathrm{cell})}<2.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ or ${g}_{\mathrm{eff}}^{(\mathrm{Kolmo})}<(7.2--32.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$, depending on the model that is assumed for the cluster magnetic field structure. We predict the radial profile of the chameleonic CMB intensity decrement. We find that the chameleon effect extends farther toward the edges of the cluster than the thermal SZ effect. Thus we might see a discrepancy between the x-ray emission data and the observed SZ intensity decrement. We further predict the expected change to the CMB polarization arising from the existence of a chameleonlike scalar field. These predictions could be verified or constrained by future CMB experiments.

Sensitive determination of gentiopicroside in medicine and bio‐fluids using luminol‐myoglobin chemiluminescence combined with flow injection technique

A novel chemiluminescence method for the determination of gentiopicroside is presented, which was based on the inhibitory effect of gentiopicroside on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system. The decrement of chemiluminescence intensity was linear with the logarithm of gentiopicroside concentration over the range from 10.0 pg mL(-1) to 500.0 ng mL(-1) (r(2) = 0.9992), with a detection limit of 3.0 pg mL(-1) (3σ). At a flow rate of 2.0 mL min(-1), a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0% (n = 5). The proposed procedure was applied successfully in the determination of gentiopicroside in pharmaceutical preparations, human urine and serum without any pretreatment procedure. The possible mechanism of the reaction was also discussed.

Structural and chemical modification of polymer composite by proton irradiation

Polymethyl methacrylate (PMMA) was synthesized by solution polymerization technique. Different concentrations of organometallic compound/palladium (II) acetylacetonate [Pd(acac)] were dispersed in PMMA. The composite films were irradiated with 3 MeV proton beam at a fluence of 10 13 ions/cm 2. The radiation induced changes in structural and chemical properties were studied by means of X-ray diffraction (XRD) and FTIR spectroscopy. The XRD results reveal that the crystalline size and crystallinity of the composite films decrease after irradiation, however crystallinity increases with filler concentration. This is due to the crystalline behavior of Pd(acac). Fourier transform infrared spectroscopy has been studied in transmittance mode. The decrement in the peak intensity is attributed to chain scissioning of the polymeric bonds. Chain scissioning is also responsible for the decrement in the crystallinity of the composites. The glass transition temperature was observed to decrease after irradiation as revealed from differential scanning calorimetry (DSC) thermograms. Scanning electron microscopy (SEM) reveals that the surface roughness increases due to irradiation.

After the Curtain Falls: On the Post-Performance Adjustment of Solo Singers

The purpose of our study was to examine the psychological experience of a particular type of performing musicians, solo singers, upon finishing their stage performance. Thirty-eight professional rock singers completed questionnaires related to their self-esteem, positive and negative affects, and purpose in life, at 3 days before and after their performance. The contribution of these variables to the prediction of the participants' sense of purpose in life before and after performance was analyzed. We also compared the scores obtained from the singers' mental health condition with the scores of nonsingers who were nonpatients, ambulatory-neurotic patients, or inpatient-psychiatric patients tested by Florian and Drory in 1990. Results showed a post-performance decrement in emotional intensity and in the singers' sense of purpose in life. The singers' ability to maintain their sense of purpose in life after the performance was predicted by their professional experience, psychological well-being, and psychological mental distress. The singers' mental health appeared better than both the ambulatory-neurotic and inpatient- psychiatric groups, but it was worse than the mental health of the nonpatients. The meanings of these findings and their implications for post-performance psychotherapy are discussed.

Success of Strategies for Combining Employment and Breastfeeding

Return to work is associated with diminished breastfeeding intensity and duration. Although more mothers breastfeed after returning to work now than earlier, research has not documented the strategies that mothers use for combining paid work and breastfeeding or their effect on breastfeeding outcomes. This study examined which strategies are associated with smaller decrements in breastfeeding intensity and longer durations. We analyzed 810 mothers from the Infant Feeding Practices Study II who worked and breastfed. We used regression and censored regression models to analyze 4 strategies that mothers used to combine these 2 activities: (1) feed directly from the breast only; (2) both pump and feed directly; (3) pump only; and (4) neither pump nor breastfeed during the work day. Outcomes were the difference in percentage of milk feeds that were breast milk between the month before and after return to work and duration of breastfeeding after return to work. Forty-three percent of mothers pumped milk at work only; 32% fed the infant directly from the breast only. These 2 strategies, along with pumping and feeding directly, were statistically similar and superior to neither pumping nor breastfeeding during the work day for the outcome of change in breastfeeding intensity. For the outcome of breastfeeding duration, the 2 strategies that included directly feeding from the breast were associated with longer duration than pumping only, whereas the strategy of neither pumping nor breastfeeding during the work day was associated with the shortest duration. Feeding the infant from the breast during the work day is the most effective strategy for combining breastfeeding and work. Ways to enable direct feeding include on-site child care, telecommuting, keeping the infant at work, allowing the mother to leave work to go to the infant, and having the infant brought to the work site. Establishing ways for mothers to feed from the breast after return to work is important to meet US breastfeeding goals.

Study on the Resistance to Aging of CdS Quantum Dots Encapsulated by PAMAM Dendrimers

CdS quantum dots(QDs)of 2.5nm were prepared using G4.5 PAMAM dendrimer templates and characterized by HRTEM and EDS.The aging of synthesized QDs stored in the dark at room- temperature was studied through UV-vis and PL spectrophotometer.The width at half-maximum of the peak(WHM)of the UV-vis and PL spectra becomes narrower,meanwhile the PL intensity increases obviously during the first 5d.Afterwards,the WHM gets broader and the PL intensity decreases slowly during the following 6 months.The results suggest that CdS QDs show a size-focusing growth within the first 5d,but a size-defocusing growth in the following 6 months.However,the increment of CdS QDs size is less than 0.3nm,and the decrement of PL intensity is about 22% after 6 months of aging. The excellent resistance to aging of CdS QDs is attributed to the coordination and template effects of PAMAM dendrimers.

Smooth Muscle Myosin Phosphorylated at Single Head Shows Sustained Mechanical Activity

Smooth muscle contraction is regulated by the phosphorylation of myosin. It is well known that tonic smooth muscles can maintain force with low energy consumption (latch state); however, the molecular mechanism underlying this phenomenon is unresolved. Here we show that single-head phosphorylated smooth myosin (SHPMII) exhibits fast ( approximately 24 s(-1)) and slow prolonged ( approximately 1 s(-1)) actin interactions, whereas double-head phosphorylated myosin (DHPMII) predominantly exhibits the fast ( approximately 29 s(-1)) interaction, suggesting that the phosphorylated head of SHPMII is mechanically as active as that of DHPMII. Both the fast and the slow actin interactions of SHPMII support the positive net mechanical displacement of actin. The actin translocating velocity of SHPMII was much slower than that of DHPMII, which is consistent with the slow actin interaction of SHPMII. We propose that the "latch state" can be explained by the motor characteristics of SHPMII that is present during the sustained phase of contraction.

Sensitive Chemiluminescence Assay for Patulin in Apple Juice by Flow Injection

A sensitive chemiluminescence (CL) procedure for the determination of patulin by flow injection is described. It was found that patulin inhibits the CL generated from the luminol–dissolved oxygen system significantly. The decrement of chemiluminescence intensity was linear with the patulin concentration over the range from 0.04 to 10.0 ng mL−1 with a detection limit of 0.01 ng mL−1 (3σnoise). At a flow rate of 2.0 mL min−1, a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0% (n=5). The proposed method was applied successfully in the determination of patulin in apple juice, and the recovery was between 96.9% and 103.9%.

Ultrasensitive assay of clindamycin in medicine and bio‐fluids with chemiluminescence detection

A simple chemiluminescence (CL) method using flow injection has been developed for the determination of clindamycin, based on the inhibitory effect of clindamycin on the CL generated from the luminol-K(3)Fe(CN)(6) system in alkaline medium. It was found that the decrement of CL intensity was linear with the logarithm of clindamycin concentration over the range 0.7-1000 ng/mL. The detection limit was 0.2 ng/mL with a relative standard deviation (RSD) of <5.0% (n = 7). At a flow rate of 3.0 mL/min, a complete analytical process could be performed within 0.5 min, including sampling and washing. The proposed procedure was applied successfully to the determination of clindamycin in pharmaceutical preparations and human urine without pretreatment.

The He$\rm_{II}$ Fowler lines and the O$\rm_{III}$ and N$\rm_{III}$ Bowen fluorescence lines in the symbiotic nova RR Telescopii

A new measure of reddening (E$_{(B-V)}$$\sim$0.00) has been obtained from the comparison between the observed and the theoretical intensity decrement for 20 emission lines of the $\ion{He}{ii}$ Fowler (n$\to$3) series. This value has been confirmed by the STIS and IUE continuum distribution, and by the value of n$_H$ from the damped profile of the IS H Ly-$\alpha$ line. We have obtained very accurate measurements for about thirty Bowen lines of $\ion{O}{iii}$ and a precise determination of the efficiency in the O1 and O3 excitation channels (18 % and 0.7 %, respectively). The relative $\ion{O}{iii}$ intensities are in good agreement with the predictions by Froese Fischer (1994). A detailed study of the decays from all levels involved in the Bowen mechanism has lead to the detection of two new $\ion{O}{iii}$ Bowen lines near $\lambda$ 2190. High resolution IUE data have shown a nearly linear decline with time, from 1978 to 1995, in the efficiency of the O1 and O3 processes, with a steeper slope for the O3 channel. A detailed study of the $\ion{N}{iii}$ $\lambda$ 4640 lines and of their excitation mechanism has shown that, recombination and continuum fluorescence being ruled out, line fluorescence remains the only viable mechanism to pump the 3d $^2D_{5/2}$ and 3d $^2D_{3/2}$ levels of $\ion{N}{iii}$. We point out the important role of multiple scattering in the resonance lines of $\ion{O}{iii}$ and $\ion{N}{iii}$ near $\lambda$ 374 and show that the observed $\ion{N}{iii}$ line ratios and intensities can be explained in terms of line fluorescence by the three resonance lines of $\ion{O}{iii}$ at $\lambda$$\lambda$ 374.432, 374.162 and 374.073 under optically thick conditions.

Carbohydrate Supplementation and Endurance Performance of Moderate Altitude Residents at 4300 m

Recent work from our laboratory demonstrated that carbohydrate supplementation (CHOS) during exercise improved prolonged time-trial (TT) performance of sea-level residents (SLR) living at 4300 m while they were in daily negative energy balance (- 1250 kcal x day (-1); [ ]). The purposes of the current study were to determine during initial exposure to 4300 m:1) whether CHOS also improves TT performance of moderate altitude residents (MAR) who are in energy balance and 2) if acclimatization to moderate elevations benefits TT performance. Fifteen Air Force Academy (AFA) active duty members (age: 30 +/- 1 yrs; mean +/- SE), who had been living at approximately 2000 m for 21 +/- 3 months performed a maximal-effort 720-kJ cycle TT at the AFA and at Pikes Peak (PP), CO, (4300 m) on days 1 (PP1) and 3 (PP3). Daily energy intake and expenditure were maintained similarly at the AFA and PP. At the start of the TTs at PP, and then every 15 min thereafter, 9 subjects drank a 10 % CHO solution (0.175 g x kg (-1) body weight) and 6 subjects drank a placebo (PLA) solution. All subjects were allowed to freely adjust the power output of the cycle ergometer and drank water AD LIBITUM. Performance time did not differ between groups on PP1 (CHOS vs. PLA; 101 +/- 8 vs. 116 +/- 10 min) or PP3 (95 +/- 8 vs. 107 +/- 12 min). For both groups, cycle times on PP1 and PP3 were longer compared to the AFA (p<0.01) and were improved from PP1 to PP3 (p<0.05). Exercise intensity (i.e., % peak oxygen uptake) was maintained similarly at approximately 62 % during the TTs at the AFA and PP. Blood glucose was 1.5 to 2.0 mmol x L (-1) higher for CHOS vs. PLA (p<0.01). It was concluded that CHOS provided no TT performance benefit for MAR at 4300 m when energy balance was maintained. However, the decrements in TT performance and exercise intensity were attenuated at 4300 m in MAR compared to those of SLR as a result of acclimatization attained while living for nearly 2 years at approximately 2000 m.

In vitro monitoring of clindamycin in human urine using flow injection chemiluminescence

A sensitive chemiluminescence method for the determination of clindamycin is presented. The method is based on the inhibitory effect of clindamycin on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system. The decrement in chemiluminescence intensity is linear with the logarithm of the clindamycin concentration over the range of 0.1–70.0 ng mL−1 (r2 = 0.9995), with a detection limit of 0.03 ng mL−1 (3σ). At a flow rate of 2.0 mL min−1, the complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0% (n = 5). The procedure was applied to the determination of clindamycin in human serum and in monitoring the excretion of clindamycin in human urine samples without any pretreatment process. It was found that the excretive clindamycin concentration reached its maximum 3 hours after oral administration. The clindamycin excretive ratio in 9 hours was 10.84% in the body of the volunteer.

Two separate mechanisms underlie auditory change detection and involuntary control of attention

We used behavioral and event-related potential (ERP) measures to study the neural mechanisms of involuntary attention switching to changes in unattended sounds. Our subjects discriminated two equiprobable sounds differing in frequency (fundamental frequency 186 or 196 Hz) while task-irrelevant intensity decrements or increments (−3, −6, −9, +3, +6, or +9 dB, standard intensity 60 dB HL) infrequently occurred in the same sounds. In line with the results of previous studies, discrimination performance deteriorated with increasing magnitude of the task-irrelevant intensity change. However, these distraction effects were dissimilar for intensity increments and decrements: while there were no differences in reaction time (RT) between intensity decrements and increments, hit rates (HR) were lower for large intensity increments than for large decrements. ERPs to task-irrelevant intensity increments and decrements were also distinctly different: the response to intensity increments consisted of an N1 enhancement, mismatch negativity (MMN), and P3a, while the response to intensity decrements consisted only of MMN. These results are consistent with the assumption that two separate mechanisms (indexed by N1 and MMN) underlie auditory change detection. However, the finding that distinct distraction effects were obtained for both intensity decrements and increments but that the P3a is elicited only by the intensity increments seems to suggest that P3a may not be regarded as a general index of attentional shift but rather it is only generated in conditions in which an enhanced N1 is elicited, too.

Rapid determination of clindamycin in medicine with myoglobin–luminol chemiluminescence system

A sensitive chemiluminescence method, based on the inhibitory effect of clindamycin on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system, is proposed for the determination of clindamycin. The decrement of chemiluminescence intensity is linear with the logarithm of clindamycin concentration over the range from 0.1 to 70.0 ng ml −1 ( r 2 = 0.9995), with the detection limit of 0.03 ng ml −1 (3 σ). At a flow rate of 2.0 ml min −1, a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0% ( n = 5). The proposed procedure was applied successfully to the determination of clindamycin in capsules without any pretreatment process.

Detection and discrimination of monaural and binaural increments and decrements of intensity with a temporal fringe

Detection thresholds are larger for brief, monaural intensity increments in long-duration stimuli than for decrements. This experiment assessed the contribution of a decrement in one ear to direction discrimination of an interaural intensity difference (IID), where a brief intensity increment was presented at one ear and an equal-magnitude intensity decrement at the other. In two-interval monaural tasks, thresholds were measured for detection of an increment, a decrement, and discrimination of the two. In single-interval binaural tasks, thresholds were measured for identifying ear of presentation of an increment, a decrement, and for identification of direction of IID achieved by presenting an increment and decrement to opposite ears. In all cases, thresholds were measured for a 5-ms probe segment as a function of its temporal position in a 50-ms stimulus (broadband noise). The major results: (1) Thresholds for discriminating the ear of presentation of a decrement were much larger than those for simply detecting the decrement monaurally; (2) Interaural thresholds were slightly better when both increment and decrement were present relative to increment alone. These results indicate that the decrements contributed to binaural discrimination, although by themselves the same decrements were detectable but, at best, weakly lateralizable. [Work supported by NIDCD DC00683.]

“…and were instructed to read a self-selected book while ignoring the auditory stimuli”: The effects of task demands on the mismatch negativity

Objective The Mismatch Negativity (MMN) is commonly recorded while the subject is reading, and instructed to ignore the auditory stimuli. It is generally assumed that the demands of the diversion task will have no effect on the MMN. Several studies, however, have reported that a diversion task presumably requiring strong attentional focus is associated with a smaller MMN than that elicited during a less demanding task. This study examines the effect of variations in the classical reading paradigm on the MMN. Methods In Experiment 1, event-related potentials (ERP) were recorded while subjects were presented with standard (80 dB SPL 1000 Hz) and frequency deviant (1050 Hz) stimuli. Subjects were instructed to ignore the tone pips and, in separate conditions, engage in different tasks. They were asked to read a text or to sit passively. Subjects were informed that they would subsequently be queried or not about the content of the reading. In Experiment 2, the auditory sequence included the same standard (80 dB SPL 1000 Hz) but the deviant was changed to an intensity decrement (70 dB SPL). A different sample of subjects was again asked to ignore the auditory stimuli and engage in different reading tasks that would or not be followed by query. Results In all task conditions, MMN was elicited by the frequency and intensity change. The intensity MMN did not significantly vary with task. A significant effect of task was, however, found for the frequency MMN. Its amplitude was largest when subjects were later queried about their reading. Conclusions This finding is counter-intuitive in light of previous research on the attentional modulation of the MMN. The pattern of frequency MMN results may relate to the differences in cortical excitability across tasks. Significance The present results indicate that the nature of the diversion task may affect the MMN. The choice of diversion task during MMN recording should thus be carefully considered.

On-Line Monitoring of Formaldehyde In Water and Air Using Chemiluminescence Detection

A rapid and sensitive chemiluminescence flow sensor for the determination of formaldehyde was proposed in this article. The analytical reagents involved in chemiluminescence (CL) reaction, luminol and KIO4, were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and KIO4, which were eluted from the column through water injection, was decreased in the presence of formaldehyde. Formaldehyde was sensed by measuring the decrement of CL intensity, which was observed linear over the logarithm of formaldehyde concentration range of 5.0-1000.0 ng mL−1, and the limit of detection is 1.8 ng mL−1 (3σ). At a flow rate of 2.0 mL min−1, including sampling and washing, could be performed in 0.5 min with a relative standard deviation of less than 3.0%. The flow sensor offered reagentless procedures and remarkable stability in determination of formaldehyde, and could be easily re-used over 80 h. The proposed flow microsensor was applied successfully in the determination of formaldehyde in artificial water samples and air.