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This study was performed to investigate the origin of the photoluminescence (PL) properties of hydrothermally-synthesized water-soluble CuInS2 (CIS) quantum dots (QDs). The corresponding PL decay profiles, time-resolved PL spectra, and excitation intensity dependence of the PL spectra were evaluated. The decay profiles exhibited a strong dependence on the detection energy, and the peak of the time-resolved PL spectra shifted to lower energies with increasing time. With increasing excitation light intensity, the PL peak shifted to the high-energy side. These experimental results were consistent with the characteristics of donor–acceptor pair emission. The PL properties of Cu-doped and non-doped CdSe QDs, which show Cu-related and defect-related PL emission, respectively, were compared. Based on these results, it was concluded that donor–acceptor pair emission is the underlying mechanism of the PL of the hydrothermally-synthesized water-soluble CIS QDs.

Objective: Acupuncture, as an important part of Traditional Chinese Medicine, has been practiced for thousands of years in China and now all over the world, but the underlying neuroanatomical basis is still poorly understood. This article explores how acupuncture drives autonomic reflexes and why the widely used Streitberger sham-needling control should be revisited. Method: This article summarizes modern studies, suggesting that functional connections between somatic tissues and internal organs may be explained via somato–autonomic reflexes. Results: Modern studies have revealed a few organizational rules regarding how acupuncture drives distinct somatosensory autonomic pathways, including acupoint selectivity and intensity dependence. Activation of these autonomic pathways modulates various body physiologic functions, such as gastrointestinal motility and systemic inflammation. Meanwhile, extensive anatomical and functional characterization of the somatosensory system raises a question about the widely used Streitberger sham-needling control. Specifically, the skin epidermis and hair follicles contain mechanically sensitive afferents, whose activation by this sham stimulation could modulate pain and the autonomic nervous system. Conclusions: A deeper understanding of the underlying neuroanatomical basis of acupuncture is crucial for optimizing stimulation parameters and designing proper sham-controls to demonstrate and improve the efficacy and the safety of using this modality to treat human conditions.

Background: ‪Respiratory muscle strength is an important indicator of human health and sport condition. The aim of this study was to assess the test/retest reliability of mouth pressure (MP) measured by a created pressure sensor mouthpiece in the sitting position and during bench pressing at various intensities. Material and methods: ‪23 healthy athletes were measured in 3 separate sessions for MP in the sitting position and during flat bench press at an intensity of one repetition maximum (1RM), 3 x 90% of 1RM, 8 x 80% of 1RM and 12 x 60% of 1RM. Results: ‪The measurement device showed acceptable reliability with ICC (Intraclass correlation) ranging from 0.75 to 0.95, where the highest reliability was reached in between repetitions, and slightly decreased when measurements were done in different sessions. The ANOVA showed differences between mouth pressure at different exercise loads (F4, 56 = 22.18, p< 0.001),with the highest MP measured in the sitting position, followed by 90% of 1RM, 80% of 1RM and 60% of 1 RM load. Conclusions: ‪This study shows acceptable reliability of MP measurement by a mouthpiece device with piezo-resistant sensor. The MP depends on the exercise intensity during the bench press and is higher in sitting than in the supine body position.

Active research on halide perovskites has given us a deep understanding of this family of materials and their potential for applications in advanced optoelectronic devices. One of the prominent outcomes is the use of perovskite materials for nonlinear optical applications. Two-photon absorption in perovskites, in particular their nanostructures, has been extensively studied and shows huge promise for many applications. However, we are still far from a thorough understanding of two-photon absorption in halide perovskites from a micro to macro perspective. Here we summarize different techniques for studying the two-photon absorption in nonlinear optical materials. We discuss the in-depth photophysics in two-photon absorption in halide perovskites. A comprehensive summary about the factors which influence two-photon absorption provides the direction to improve the two-photon absorption properties of halide perovskites. A summary of the recent applications of two-photon absorption in halide perovskites provides inspirations for engineers to utilize halide perovskites in two-photon absorption device development. This review will help readers to have a comprehensive and in-depth understanding of the research field of two-photon absorption of halide perovskites from microscopic mechanisms to applications. The article can serve as a manual and give inspiration for future researchers.

In this study, a simple energetically based dynamical system model of tropical cyclone (TC) intensification is modified to account for the observed dependence of the intensification rate (IR) on the storm intensity. According to the modified dynamical system model, the TC IR is controlled by the intensification potential (IP) and the weakening rate due to surface friction beneath the eyewall. The IP is determined primarily by the rate of change in the potential energy available for a TC to develop, which is a function of the thermodynamic conditions of the atmosphere and the underlying ocean, and the dynamical efficiency of the TC system. The latter depends strongly on the degree of convective organization within the eyewall and the inner-core inertial stability of the storm. At a relatively low TC intensity, the IP of the intensifying storm is larger than the frictional weakening rate, leading to an increase in the TC IR with TC intensity in this stage. As the storm reaches an intermediate intensity of 30-40 m s-1, the difference between IP and frictional weakening rate reaches its maximum, concurrent with the maximum IR. Later on, the IR decreases as the TC intensifies further because the frictional dissipation increases with TC intensity at a faster rate than the IP. Finally, the storm approaches its maximum potential intensity (MPI) and the IR becomes zero. The modified dynamical system model is validated with results from idealized simulations with an axisymmetric nonhydrostatic, cloud-resolving model.

In this paper the current-voltage characteristics of organic solar cells (OSC) is analyzed in terms of equivalent lumped parameter circuit at different level of insolation. In particular, starting from a circuital model based on a three-diode configuration, a set of formulas is proposed to describe the dependence of lumped circuital parameters on irradiance intensity and consequently the behaviour of organic solar cells from dark to high irradiance conditions. These expressions are achieved by using a trail and error approach applied to the fitting procedure of measured I-V curves at different irradiance levels. The achieved model with parameters dependent on irradiance level allows us to use a single circuit for the analysis of OSC under different operating conditions: this is the first step for the integration of OSC circuital model in photovoltaic system simulator, but also can furnish a novel point of view for the advance of the OSC applied research. Experimental measurements are used to setup the model and for its successive validation on two different kind of organic solar cells.

Motivated by possible application of InGaN/GaN multi-quantum well solar cells in hybrid concentrated photovoltaic / solar thermal power conversion systems, we have analyzed the temperature and intensity dependence of the open-circuit voltage of such devices up to 725 K and more than 1000 suns. We show that the simple ABC model routinely used to analyze the measured quantum efficiency data of InGaN/GaN LEDs can accurately reproduce the temperature and intensity dependence of the measured open-circuit voltage if a temperature-dependent Shockley–Read–Hall lifetime is used and device heating is taken into account.

Some studies suggest that women with primary dysmenorrhea have distinct emotional or personality features. For example, they might exaggerate their responses to external stimuli, such as to intensity-increasing auditory stimuli. Fifteen women with primary dysmenorrhea and 15 healthy women were invited to undergo tests of the intensity dependence of auditory evoked potentials (IDAEP), the Functional and Emotional Measure of Dysmenorrhea, and the Plutchik–van Praag Depression Inventory. Study participants with dysmenorrhea showed higher Functional and Emotional scale scores and stronger IDAEP. Regarding the IDAEP generation, the source inversion of N1 and P2 disclosed the activated bilateral superior temporal gyri, medial and superior prefrontal gyri in all participants, and additionally, the middle frontal gyri in dysmenorrhea patients. We report a pronounced IDAEP in primary dysmenorrhea, which indicates the decreased cerebral serotonergic innervations and points to increased activations in the prefrontal and frontal areas in the disorder. Perspective Using an IDAEP technique, the authors found decreased serotonergic innervation and altered cerebral activation in women with primary dysmenorrhea, which might offer some pharmacotherapeutic clues for the disorder.

Perception of a facial expression can be altered or biased by a prolonged viewing of other facial expressions, known as the facial expression adaptation aftereffect (FEAA). Recent studies using antiexpressions have demonstrated a monotonic relation between the magnitude of the FEAA and adaptor extremity, suggesting that facial expressions are opponent coded and represented continuously from one expression to its antiexpression. However, it is unclear whether the opponent-coding scheme can account for the FEAA between two facial expressions. In the current study, we demonstrated that the magnitude of the FEAA between two facial expressions increased monotonically as a function of the intensity of adapting facial expressions, consistent with the predictions based on the opponent-coding model. Further, the monotonic increase in the FEAA occurred even when the intensity of an adapting face was too weak for its expression to be recognized. These results together suggest that multiple facial expressions are encoded and represented by balanced activity of neural populations tuned to different facial expressions.

Background: High-intensity interval training (HIIT) with interspersing active recovery is an effective mode of exercise training in cohorts ranging from athletes to patients. Here, we assessed the intensity-dependence of the intervals and active recovery bouts for permitting a sustainable HIIT protocol.\ud Methods: 14 males completed 4x4-minute HIIT protocols where intensities of intervals ranged 80-100% of maximal oxygen uptake (VO2max) and active recovery ranged 60-100% of lactate (La-) threshold (LT). Blood La- measurements indicated fatigue, while tolerable duration of intervals indicated sustainability.\ud Results: HIIT at 100% of VO2max allowed 44±10% [30-70%] completion, i.e. fatigue occurred after 7minutes:6seconds of the intended 16 minutes of high intensity, whereas HIIT at 95-80% of VO2max was 100% sustainable (p0.05). Blood La- concentration [La-] increased to 9.3±1.4mM during HIIT at 100% of VO2max, whereas at 80-95% of VO2max stabilised at 2-6mM in an intensity-dependent manner (p

Our understanding of how peripheral damage-sensing neurons (nociceptors) respond to noxious stimuli is fundamental to the development of effective analgesics. To date, numerous studies have presented diverging hypotheses on how nociceptors encode modality-specific stimuli, including labelled-line, intensity dependence or pattern theory. In this short review, we appraise data from electrophysiological, behavioural, imaging and molecular expression studies from the last 60 years, in order to obtain a coherent view of modality-specific sensing in peripheral sensory neurons. We propose a mechanistic explanation for the broad range of values obtained for the incidence of polymodal nociceptors that reconciles apparently contradictory data.

The role of Universal Time (UT) dependence on storm-time development has remained an unresolved question in geospace research. This study presents new insight into storm progression in terms of the UT of the storm peak. We present a superposed epoch analysis of solar wind drivers and geomagnetic index responses during magnetic storms, categorized as a function of UT of the storm peak, to investigate the dependency of storm intensity on UT. Storms with Dst minimum less than - 100 nT were identified in the 1970 - 2012 era (305 events), covering four solar cycles. The storms were classified into 6 groups based on the UT of the minimum Dst (40 to 61 events per bin), then each grouping was superposed on a timeline that aligns the time of the minimum Dst. Fifteen different quantities were considered, seven solar wind parameters and eight activity indices derived from ground-based magnetometer data. Statistical analyses of the superposed means against each other (between the different UT groupings) were conducted to determine the mathematical significance of similarities and differences in the time series plots. It was found that the solar wind parameters have no significant difference between the UT groupings, as expected. The geomagnetic activity indices, however, all show statistically significant differences with UT during the main phase and/or early recovery phase. Specifically, the 02:00 UT groupings are stronger storms than those in the other UT bins. That is, storms are stronger when the Asian sector is on the nightside (American sector on the dayside) during the main phase.

Based on Fresnel–Kirchhoff diffraction theory, the effect of high order nonlinearities and saturable Kerr media in Z-scan experiments are theoretically investigated. Analytical expressions were obtained for the Z-scan curve, which can be strongly affected by the pump intensity. Moreover, empirical relationships were found to describe the intensity dependence of the peak-valley distance and the transmittance difference, allowing an accurate determination of parameters such as high-order nonlinearities, the saturation intensity and the confocal parameter.

The neuroanatomical basis behind acupuncture practice is still poorly understood. Here, we used intersectional genetic strategy to ablate NPY+ noradrenergic neurons and/or adrenal chromaffin cells. Using endotoxin-induced systemic inflammation as a model, we found that electroacupuncture stimulation (ES) drives sympathetic pathways in somatotopy- and intensity-dependent manners. Low-intensity ES at hindlimb regions drives the vagal-adrenal axis, producing anti-inflammatory effects that depend on NPY+ adrenal chromaffin cells. High-intensity ES at the abdomen activates NPY+ splenic noradrenergic neurons via the spinal-sympathetic axis; these neurons engage incoherent feedforward regulatory loops via activation of distinct adrenergic receptors (ARs), and their ES-evoked activation produces either anti- or pro-inflammatory effects due to disease-state-dependent changes in AR profiles. The revelation of somatotopic organization and intensity dependency in driving distinct autonomic pathways could form a road map for optimizing stimulation parameters to improve both efficacy and safety in using acupuncture as a therapeutic modality.

We demonstrate a temporal imaging system that can capture events with unknown time-of-arrival in the time domain without the need to synchronize the signal. The temporal imaging system is based on a time-lens that uses a high repetition-rate fiber laser for the pump wave together with a time-stretch scheme. After dispersion, the timing between adjacent pump pulses is smaller than the pulse width. Therefore, the signal interacts with one of the pump pulses with high probability, regardless of its arrival time. We discuss the intensity dependence and temporal aberrations of such an imaging system and demonstrate a direct temporal imaging of the buildup dynamics of solitons.

Objective The literature suggests that the N1 and P2 waves of the auditory ERP are dissociable at the developmental, experimental, and source levels. At the experimental level, inconsistent findings suggest different effects of intensity on the amplitudes of the auditory N1 and P2. Our main goal was to analyze the intensity dependence of the auditory N1 and P2 while controlling for habituation effects. Methods We examined the intensity dependence of both averaged and single-trial auditory N1 and P2 waves elicited in a repeated-stimulation protocol. Results N1 and P2 revealed similar intensity dependence on both standard and filter denoised ERP, with a linear tendency for higher intensities to elicit higher absolute peak amplitudes. At the single-trial level, both waves covary irrespective of stimulus intensity and trial order. Conclusions Our results suggest that stimulus intensity variation induces similar effects on both and N1 and P2 and partially contradict previous data that classified the P2 as a non-habituating component. Significance Our findings contribute to the ongoing discussion on the functional significance of the auditory P2 deflection. In addition, the present work demonstrated the applicability of a filter denoising method for single-trial estimation in the analysis of the experimental effects on auditory ERP components.

Photosensitivity light intensity dependence of holographic grating recording in three azobenzene molecular glassy films (denoted as WE-3, ZWK-3, ZWK-2TB) and in one chalcogenide glassy film As40S15Se45(As-S-Se) has been experimentally studied in the intensity range from 0.0034 to 1.13 W/cm2at 633 nm. It is found that photosensitivity increases when recording light intensity is increased. The physical reasons are discussed and a simple mathematical model is given explaining the obtained results.

The influence of reaction order and trap-assisted recombination on continuous-wave photoinduced absorption measurements is clarified through analytical calculations and numerical simulations. The results reveal the characteristic influence of different trap distributions and enable distinguishing between shallow exponential and Gaussian distributions as well as systems dominated by direct recombination by analyzing the temperature dependence of the in-phase and quadrature signals. The identifying features are the intensity dependence of the in-phase at high intensity, $\textit{PA}_\text{I}\propto I^{\gamma_\text{HI}}$, and the frequency dependence of the quadrature at low frequency, $\textit{PA}_\text{Q}\propto \omega^{\gamma_\text{LF}}$. For direct recombination $\gamma_\text{HI}$ and $\gamma_\text{LF}$ are temperature independent, for an exponential distribution they depend on the characteristic energy $E_\text{ch}$ as $\gamma_\text{HI}=1/(1+E_\text{ch}/kT)$ and $\gamma_\text{LF}=kT/E_\text{ch}$ while a Gaussian distribution shows $\gamma_\text{HI}$ and $\gamma_\text{LF}$ as functions of $I$ and $\omega$, respectively., Comment: Accepted manuscript

Intensity-dependent auditory evoked potentials (IDAP) were shown to be increased in highly impulsive individuals. As impulsivity is one of the core symptoms of attention deficit/hyperactivity disorder (ADHD), patients with ADHD were expected to exhibit an enhanced IDAP. Twenty-five ADHD patients taking methylphenidate and 21 healthy control participants were given diagnostic questionnaires including the Barratt Impulsivity Scale and IDAP was assessed with five-tone intensities. Amplitude, latency, and intensity slope of the N1, P2, and N1/P2 were determined. Contrary to our hypothesis, there was no significant group difference with regard to N1 amplitude and ADHD patients exhibited significantly lower P2 amplitude at high intensity and a flatter N1/P2 slope of the stimulus intensity function than healthy controls. Motor impulsivity, a subscale of the Barratt impulsivity scale, showed a significantly negative correlation with P2 amplitude within the ADHD group. The unexpected results could be due to the effect of methylphenidate.

Today s perovskite solar cells PSCs are limited mainly by their open amp; 8208;circuit voltage VOC due to nonradiative recombination. Therefore, a comprehensive understanding of the relevant recombination pathways is needed. Here, intensity amp; 8208;dependent measurements of the quasi amp; 8208;Fermi level splitting QFLS and of the VOC on the very same devices, including pin amp; 8208;type PSCs with efficiencies above 20 , are performed. It is found that the QFLS in the perovskite lies significantly below its radiative limit for all intensities but also that the VOC is generally lower than the QFLS, violating one main assumption of the Shockley amp; 8208;Queisser theory. This has far amp; 8208;reaching implications for the applicability of some well amp; 8208;established techniques, which use the VOC as a measure of the carrier densities in the absorber. By performing drift amp; 8208;diffusion simulations, the intensity dependence of the QFLS, the QFLS amp; 8208;VOC offset and the ideality factor are consistently explained by trap amp; 8208;assisted recombination and energetic misalignment at the interfaces. Additionally, it is found that the saturation of the VOC at high intensities is caused by insufficient contact selectivity while heating effects are of minor importance. It is concluded that the analysis of the VOC does not provide reliable conclusions of the recombination pathways and that the knowledge of the QFLS amp; 8208;VOC relation is of great importance

An auditory augmenting/reducing ERP paradigm recorded for 5 intensity tones with emotional visual stimulation was used, for the first time, to test predictions derived from the revised Reinforcement Sensitivity Theory (rRST) of personality with respect to two major factors: behavioral inhibition system (BIS), fight/flight/freeze system (FFFS). Higher BIS and FFFS scores were negatively correlated with N1/P2 slopes at central sites (C3, Cz, C4). Conditional process analysis revealed that the BIS was a mediator of the association between the N1/P2 slope and the FFFS scores. An analysis of covariance showed that lower BIS scorers exhibited larger N1/P2 amplitudes across all tone intensities while watching negative, positive and neutral pictures. Additionally, lower FFFS scorers compared to higher FFFS scorers disclosed larger N1/P2 amplitudes to the highest tone intensities and these differences were even more pronounced while watching positive emotional pictures. Findings were explained assuming the operation of two different, but related processes: transmarginal inhibition for the BIS; the attention/emotional gating mechanism regulating cortical sensory input for the FFFS trait. These findings appear consistent with predictions derived from the rRST, which traced fear and anxiety to separate but interacting neurobehavioural systems.

International audience; Bulk wave excitation from the surface of a LiNbO3 crystal by a system of planar electrodes A V Muromets, V B Voloshinov and I A Kanonin Investigation of the nonlinear absorption of [M(Et2timdt)2] (M = Pd, Pt) in the pico-andnanosecond timescales using the Z-scan technique T Cassano, R Tommasi, M Arca et al. Green synthesis and third-order nonlinear optical properties of 6-(9H-carbazol-9-yl) hexyl acetate Abstract. The nonlinear absorption (NLA) was studied by open-aperture Z-scan experiments in the chemically reduced nominally pure LiNbO 3 crystals at cw-illumination with the red (644 nm) and green (514.5 nm) laser beams. The magnitude of the measured NLA is considerably different from the reported Z-scan results obtained in as-grown LiNbO 3. The positive sign of NLA obtained with the red light has been related to the generation of the small bound polarons absorbing in red and near-IR ranges. Application of green light results in the light-induced transparency, i.e. the Z-scan traces show negative sign of NLA. Intensity dependence of Z-scan traces allows for conclusion that the photo-induced dissociation of small Nb Li 4+ :Nb Nb 4+ bipolarons and sequent generation of small polarons gives the dominating contribution to the nonlinear optical absorption in reduced crystals with a large bipolarons concentration.

Background Many studies report a habituation deficit of visual evoked potentials (VEP) and/or increased intensity dependence of auditory evoked cortical potentials (IDAP) in episodic migraine patients between attacks. These findings have a pathophysiological interest, but their diagnostic utility is not known. Aims To perform an audit on a large database of interictal VEP and IDAP recordings in episodic migraine patients and evaluate their diagnostic accuracy. Methods We pooled data for VEP habituation and IDAP measured in 624 episodic migraineurs (EM) and 360 healthy volunteers (HV) from three centers. Thresholds were calculated by Receiver Operating Curve analysis and used to calculate sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-) and the accuracy of each test, using ICHD diagnostic criteria as the gold standard. Results In EM, VEP habituation was significantly lower than in HV, and IDAP slopes were significantly steeper. VEP (five blocks of 50 responses), VEP (six blocks of 100 responses) and IDAP had respectively 61.0%, 61.4% and 45.7% sensitivity, and 77.9%, 77.9% and 87.2% specificity. Their positive (LR+) and negative (LR-) likelihood ratios were respectively 2.760, 2.778, 3.570 and 0.500, 0.495, 0.623, with diagnostic accuracies of 65.3%, 69.0% and 54.3%. In combined VEP + IDAP recordings, an abnormality of at least one test had 83.4% sensitivity, 66.7% specificity, 2.504 LR+, 0.249 LR− and 81.1% accuracy. Conclusions In this large database, VEP habituation is significantly reduced and IDAP increased in episodic migraine patients between attacks. Taken alone, neither VEP nor IDAP has sufficient diagnostic accuracy. However, when both tests are performed in the same patient, an abnormality of at least one of them is highly predictive of interictal episodic migraine.

We examined microenvironment-sensitive fluorescent 2′-deoxyuridines labeled with fluorene derivatives that exhibited solvent-dependent photophysical properties. The high sensitivity of the fluorescence shift and the nucleoside intensity dependence on solvent polarity provided information useful for estimating the polarity of the environment surrounding the fluorescent nucleoside.

We have used photoinduced absorption (PA) spectroscopy and measured the intensity dependence on thin films of 1:1 blends of regioregular-poly(3-hexylthiophene):PCBM before and after annealing as well as on 1:1 blends of regiorandom-poly(3-hexylthiophene):PCBM. We have calculated the bimolecular recombination coefficients from the out-of-phase component of the photoinduced absorption. Annealing shows no change in the bimolecular recombination coefficients of rr-P3HT:PCBM, but the increased PA amplitude suggests that the geminate (monomolecular) recombination is reduced. In rra-P3HT:PCBM, the bimolecular recombination coefficient estimated by the same method (disregarding dispersion) is significantly smaller, indicating together with a low PA amplitude that the recombination is primarily geminate.

It is crucially required to understand charge traps in CH3NH3PbI3 perovskites, which severely affect the charge recombination mechanism and hence have a critical impact on photovoltaic performance. Herein, we studied the photoexcited dynamics of CH3NH3PbI3 perovskites with different grain sizes by measuring the intensity dependence of time-resolved photoluminescence (PL). As a result, we found that the PL decay for all the samples can be well analyzed using bimolecular radiative recombination and trap-assisted Shockely–Read–Hall recombination models. We discuss how the PL dynamics impact the photovoltaic performance of CH3NH3PbI3 perovskite solar cells on the basis of the recombination analysis.

This paper investigates how nonuniform generation and inefficient collection of electrons influence the dynamic photocurrent and photovoltage response of nanostructured photoelectrodes. The standard diffusion model theory of small amplitude light intensity modulated photocurrent (IMPS) and photovoltage (IMVS) spectroscopy is refined and generalized to an arbitrary electron generation profile, allowing straightforward coupling to any optical model. Expressions are derived for the local electron concentration and IMPS and IMVS transfer functions, for localized, uniform, and exponential generation profiles. Both limited collection and nonuniform generation of electrons modify the photoelectrode thickness (d) dependence of the characteristic IMPS and IMVS time constants and complicate their interpretation. This can lead to significant overestimation of the electron diffusion coefficient, diffusion length, and collection efficiency when using common approximate relations. With near contact electron generation, theIMPS response exhibits two time constants, only the slower one of which corresponds to electron transport across the film and scales with d. In the presence of this effect it is possible that in case of two equally thick samples, the one with smaller electron diffusion coefficient displays apparently faster electron transport. These errors demonstrated by experimental IMPS data of pressed TiO(2) photoelectrodes can be minimized by using modulated light incident from the counter electrode side and avoided when analyzing the ratio of IMPS at opposite directions Of illumination.

The factors that limit photocurrent in dye solar cells (DSC) were studied by incident-photon-to-collected-electron efficiency (eta(IPCE)), optical, and photovoltaic measurements. Nanostructured TiO2 photoelectrodes were prepared by compression technique on glass substrates, and half of them were given an additional heat treatment at 450 degrees C. The spectral absorbed-photon-to-collected-electron efficiency (eta(APCE)) of the cells was determined as a function of the photoelectrode film thickness (d) and direction of illumination and analyzed in terms of electron injection (eta(INJ)) and collection (eta(COL)) efficiency. The cells with pressed-only photoelectrodes gave significantly lower photocurrents yet their eta(APCE), and thus eta(COL), increased significantly with increasing d. To analyze this result quantitatively, methods were formulated based on the standard diffusion model of electron transport in nanostructured photoelectrodes for the factorization of experimental eta(APCF) data into eta(INJ) and eta(COL) parts and subsequent estimation of the effective steady-state electron diffusion length (L). Consistent decoupling of eta(INJ) and eta(COL) was reached in a spectral region where electron generation rate was independent of d. eta(INJ) was low and strongly wavelength-dependent, which was attributed to a poor energetic matching between dye excited states and TiO2 acceptor states due to unfavorable electrolyte composition. L increased systematically with d in both types of cells. Consistent with the increase of eta(IPCE) with light intensity, the result was attributed qualitatively to the electron concentration dependence of L and for a small part to decrease of film porosity with d. The diffusion model and its predictions were reviewed, and its validity in the present case was discussed critically.

We investigated the excited-state dynamics of CH3NH3PbBr3 perovskite nanoparticles (NPs) and bulk crystals under various excitation intensity regimes using transient absorption spectroscopy. We confirmed the sub-band gap hole trap states with optical transition to the conduction band in both samples. In bulk crystals, the excited-state dynamics is independent of pump intensity. However, in NPs, pronounced intensity dependence appears. At low intensities, the hole trap states do not affect the excited-state dynamics due to the potential barrier between the photogenerated holes and the surface trap states. When the excitation density is much higher than one per NP, charge accumulation makes hot holes overcome the barrier and get trapped with electrons long living in the conduction band (?10 ns). This explains the high emissive properties of such NPs despite the existence of surface traps. However, in the application of emitting devices requiring high excitation intensity, the surface trapping becomes significant. This Letter was made possible by NPRP Grant # NPRP7-227-1-034 from the Qatar National Research Fund (a member of the Qatar Foundation). The statements made herein are solely the responsibility of the authors. Collaboration within Nano-Lund is acknowledged. Scopus

Background/Purpose It is widely assumed that damage to the peripheral hearing system is an essential prerequisite for the occurrence of tinnitus. However, previous studies have failed to target tinnitus patients with normal hearing. This study aims to investigate if tinnitus patients with normal audiological presentation demonstrate increased intensity dependence at the selected frequencies. Methods This study applied auditory cortical evoked potential test to investigate nine tinnitus patients with normal audiological presentation and nine age-and sex-matched healthy subjects without tinnitus. Auditory cortical evoked potentials (N1-P2) were elicited from stimuli at four frequencies (4000, 2000, 1000 and 500 Hz) with five intensities (50, 56, 62, 68 and 74 dB nHL). Intensity dependences by latency of N1 and amplitude of N1-P2 were surveyed at midline electrodes. Results The results showed that the intensity dependence by latency of N1 to the pooled frequencies at three midline electrodes, e.g. Fz, Cz and Pz, revealed non-significant difference. However, significant differences existed in the intensity dependence of amplitude N1-P2 to the pooled frequencies at the Fz and Cz positions. These differences suggested that tinnitus patients tended to respond less to increased sound intensity and were inclined to weaker intensity dependence. Conclusion Increased intensity dependence of N1-P2 component at the selected frequencies cannot be demonstrated in tinnitus patients with normal hearing. Restated, the edge frequency phenomenon fails to present in tinnitus patients with normal hearing, a different characteristic from tinnitus patients with hearing loss.

The nonlinear effects in optical fiber occur either due to intensity dependence of refractive index of the medium or due to inelastic-scattering phenomenon. This paper describes various types of nonlinear effects based on first effect such as self-phase modulation, cross-phase modulation and four-wave mixing. Their thresholds, managements and applications are also discussed; and comparative study of these effects is presented.

Migraineurs are characterized interictally by lack of habituation, or even potentiation, of cortical evoked potentials during repetitive stimulation and by a strong intensity dependence of auditory evoked potentials (IDAP). To determine whether these two features of sensory processing are interrelated, we have studied them simultaneously on the same recordings of auditory evoked potentials (AEPs). AEPs were obtained at four different stimulation intensities in 14 patients suffering from migraine without aura (MO) and 14 healthy volunteers (HV). For each intensity, 120 trials were averaged off-line globally and over four sequential blocks of 30 trials. IDAP was expressed by the amplitude/stimulus intensity function (ASF slope) for global and block averages. Habituation was calculated as the percentage amplitude variation between the first and fourth blocks for each stimulus intensity. The IDAP slope for global averages was higher in MO (1.05 +/- 0.27 microV/10 dB) than in HV (0.64 +/- 0.45 microV/10 dB) (P = 0.008), but IDAP slopes for block averages were greater in MO only at the fourth block (P = 0.048). First block amplitudes tended to be lower in MO, except at 80 dB. There was a potentiation of AEP amplitudes at every stimulus intensity in MO, contrasting with habituation in HV. IDAP slopes were negatively correlated with mean habituation percentages in pooled data from patients and controls (r = -0.610; P = 0.0006). This study confirms that IDAP is higher in migraineurs than in healthy controls. It also shows that the AEP habituation is replaced by potentiation at all stimulus intensities. The negative correlation found between IDAP and habituation suggests that the latter is able to have a strong influence on the former and perhaps even lead to it. In migraine, the habituation deficit amplifies the IDAP and may thus be the causal functional abnormality. We propose that it is due to a decreased pre-activation level of sensory cortices, a hypothesis also supported in this study by the lower amplitude of first AEP blocks in patients.

The presence of C—H···O hydrogen bonds in liquid cyclohexanone is concluded from a combined theoretical and vibrational spectroscopic study. The two bands present in the νCO region, clearly observed in the Raman spectrum, are assigned to ‘free’ and ‘bonded’ carbonyl groups from their temperature-dependent and solvent-dependent relative intensities. In addition, a band exhibiting the same intensity dependence in the νC–H region is tentatively assigned to the blue-shifted νC–H···(O) mode. Copyright © 2003 John Wiley & Sons, Ltd.

In this research a relation between the accuracy of restoration of the single quantum dots (QD) CdSe/CdS/ZnS cross-cut coordinates and luminescence intensity was investigated. It was shown that the limit of the accuracy of determining the coordinates of a single QD for a considerable total amount of registered photons approaches its limiting value that is comparable to the size of the QD. It also means that the installation used in the research is mechanically stable enough to reach the limiting values of determination accuracy of point emitters coordinates.

In this paper, we investigate the intensity dependence of a free–free transition in the presence of a bichromatic laser field. Based on the first Born approximation, we calculate the differential cross section and total differential cross section versus the field intensity. This dependence relates to the momentum of the incident electron, the ratio of the two frequencies, and the phase difference between the two components of the bichromatic laser field. While the two intensity components are comparable, this dependence is the most striking. The results also show that the intensity dependence relates to the geometrical configurations between the direction of polarization of the laser fields and the incident electron. PACS Nos.: 34.80Bm, 32.80Qk

It is shown that the influence of liquid temperature on the sonoluminescence (SL) intensity is different depending on the ultrasound intensity. At the ultrasound intensities not much higher than the cavitation appearance threshold the SL intensity increases with the temperature. At the ultrasound intensities considerably exceeding the cavitation threshold the SL intensity decreases with an increase of the temperature. At intermediate ultrasound intensities the SL intensity temperature dependence is extreme: the cavitation activity at first increases with temperature, reaches a maximum and then decreases. Continuous and pulsed modes of irradiation at frequencies 880 and 21.9 kHz were used in experiments.