Accurate perception of time-variant pitch is important for speech recognition, particularly for tonal languages with different lexical tones such as Mandarin, in which different tones convey ...different semantic information. Previous studies reported that the auditory nerve and cochlear nucleus can encode different pitches through phase-locked neural activities. However, little is known about how the inferior colliculus (IC) encodes the time-variant periodicity pitch of natural speech. In this study, the Mandarin syllable /ba/ pronounced with four lexical tones (flat, rising, falling then rising and falling) were used as stimuli. Local field potentials (LFPs) and single neuron activity were simultaneously recorded from 90 sites within contralateral IC of six urethane-anesthetized and decerebrate guinea pigs in response to the four stimuli. Analysis of the temporal information of LFPs showed that 93% of the LFPs exhibited robust encoding of periodicity pitch. Pitch strength of LFPs derived from the autocorrelogram was significantly (
< 0.001) stronger for rising tones than flat and falling tones. Pitch strength are also significantly increased (
< 0.05) with the characteristic frequency (CF). On the other hand, only 47% (42 or 90) of single neuron activities were significantly synchronized to the fundamental frequency of the stimulus suggesting that the temporal spiking pattern of single IC neuron could encode the time variant periodicity pitch of speech robustly. The difference between the number of LFPs and single neurons that encode the time-variant F0 voice pitch supports the notion of a transition at the level of IC from direct temporal coding in the spike trains of individual neurons to other form of neural representation.
The electrophysiological signal can reflect the basic activity of cardiomyocytes, which is often used to study the working mechanism of heart. Intracellular recording is a powerful technique for ...studying transmembrane potential, proving a favorable strategy for electrophysiological research. To obtain high-quality and high-throughput intracellular electrical signals, an integrated electrical signal recording and electrical pulse regulating system based on nanopatterned microelectrode array (NPMEA) is developed in this work. Due to the large impedance of the electrode, a high-input impedance preamplifier is required. The high-frequency noise of the circuit and the baseline drift of the sensor are suppressed by a band-pass filter. After amplifying the signal, the data acquisition card (DAQ) is used to collect the signal. Meanwhile, the DAQ is utilized to generate pulses, achieving the electroporation of cells by NPMEA. Each channel uses a voltage follower to improve the pulse driving ability and isolates each electrode. The corresponding recording control software based on LabVIEW is developed to control the DAQ to collect, display and record electrical signals, and generate pulses. This integrated system can achieve high-throughput detection of intracellular electrical signals and provide a reliable recording tool for cell electro-physiological investigation.
Derivatization is frequently used in liquid chromatography–mass spectrometry (LC-MS) to improve the ionization characteristics of analytes, and facilitate their structural elucidation and ...quantification. However, the off-line derivatization process usually requires more analysis time. Therefore, the present work develops a novel LC/post-column derivatization (PCD)/MS (LC-PCD-MS) method for rapid detection of aldehydes in complex samples. The PCD method is based on a bisulfite addition reaction with aldehydes that can be easily conducted by mixing the LC elute with an (NH4)2SO3 solution via a tee. The resulting derivatives readily produce diagnostic HSO3− ions under collision induced dissociation (CID) in the negative ion mode of MS, even at an extremely low CID energy such as 1 eV, which can significantly improve the detection selectivity of aldehydes and reduce the occurrence of false positives. The limits of detection (LODs) of hexanal and heptanal were 3 nM and 2 nM, respectively. Moreover, good linearity in the concentration range of 0.01–1 μM for hexanal and heptanal was obtained with the determination coefficient (R2) being greater than 0.996 and the intra- and inter-day relative standard deviations (RSDs) were lower than 13.5% and 17.9%, respectively, indicating the acceptable reproducibility of the method. The LC-PCD-MS method was successfully applied for the rapid quantification of aldehydes in human urine and solvent extracts of traditional Chinese medicines (TCMs). Furthermore, a precursor ion scan strategy based on the diagnostic HSO3− ion was also developed and applied for the preliminary screening of aldehydes in complex samples of cinnamon and lemongrass.
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•The PCD can be realized by mixing the LC elute and (NH4)2SO3 solution.•The PCD process enables the on-line derivatization and rapid detection of aldehydes by LC-MS.•Both PCD and ionization efficiency are almost unaffected by interferences.•The diagnostic HSO3− ion enabled preliminary screening of aldehydes in complex samples.
To resolve the excessive swelling and undesirable alkaline stability of densely functionalized type anion exchange membranes (AEMs) and to obtain high performance AEMs, quaternary ...ammonium-functionalized poly(arylene ether nitrile) (QPAEN) AEMs with dense flexible ionic side chain are prepared via nucleophilic substitution polycondensation, demethylation reaction and Williamson reaction. The densely pendent flexible long side chains with QA groups at the end provide a high conductivity and the introduced strong polar nitrile groups result in lower water uptake, excellent dimensional stability and strong alkali resistance of the AEMs. The QPAEN membrane with IEC of 1.78meqg−1 exhibits the highest hydroxide conductivity of 116.0 mScm−1 at 80°C. The high conductivity is attributed to the well-developed hydrophilic/hydrophobic phase separated morphology that constructs efficient ion conducting pathways in the membranes. High retention of hydroxide conductivity (80.2%) and ionic exchange capacity (IEC) (86.0%) was observed for the QPAEN-0.4 membrane in the degradation test in a 2M aqueous KOH solution for 480h. Moreover, the single cell performance of the as-prepared AEMs was greatly enhanced and a high peak power density of 251.3mWcm−2 at 60°C was observed.
•Quaternized dense flexible side chain poly(arylene ether nitrile) AEMs were prepared.•The AEMs showed the highest conductivity of 116.0 mScm−1 at 80°C.•The AEMs showed low swelling by the introduction of nitrile groups.•A peak power density of 251.3mWcm−2 at 60°C was achieved.
The purpose of this study was to construct a glycogen (Gly)-based nanoparticle (NP) with liver-targeted and redox response to effectively deliver resveratrol (Res) for improving nonalcoholic fatty ...liver disease (NAFLD). Herein, Gly was modified using α-lipoic acid (α-LA) and lactobionic acid (Lac) to obtain an amphiphilic polymer (Gly–LA–Lac), which was self-assembled in water and then encapsulated in Res to form Res NPs with excellent stability. As expected, the Res NPs exhibited liver-targeted and redox response release behavior. In vitro cell studies demonstrated that the nanocarrier treatment enhanced the cellular uptake of Res and reduced oxidative stress and inflammatory factor levels. Meanwhile, the in vivo tests proved that the nanocarriers effectively reduced hepatic lipid accumulation and oxidative stress levels via regulating the TLR4/NF-κB signal pathway to improve liver damage in NAFLD mice. In conclusion, this study provides a promising strategy through the construction of Gly-based nanocarriers for the encapsulation of Res to effectively alleviate the process of NAFLD.
Compressed sensing in image reconstruction has attracted attention and many studies are proposed. As we know, adding prior knowledge about the distribution of the support on the original signal to CS ...can improve the quality of reconstruction. However, it is still difficult for a recovery framework adjusts its strategy for exploiting the prior knowledge efficiently according to the current estimated signals in serial iterations. With the theory of information geometry, we propose an adaptive strategy based on the current estimated signal in each iteration of the recovery. We also improve the performance of existing algorithms through the adaptive strategy for exploiting the prior knowledge according to the current estimated signal. Simulations are presented to validate the results. In the end, we also show the application of the model in the image.
In this paper, a method for monitoring impact damage of FRP pressure vessels is discussed. To estimate the location and extent of the impact damage, strains are measured at several locations on the ...surface of the structure, and impact force identification is performed using those data so as to obtain information on the impact which caused the damage. The location and force history of the impact are identified using an identification method based on experimental transfer matrices which relate the impact force to the corresponding strain responses. Here, experimental transfer matrices are determined from the measured data acquired by impact tests that do not wreak impact damages. The location of the impact damage is predicted from the identified impact location. As to the extent of the impact damage, the peak value and the duration of the identified force history are used to estimate the damage initiation and the damage size, respectively. In order to examine the validity of the method, monitoring of impact damages induced by drop-weight impact tests is demonstrated.
OBJECTIVE:The aim of this study was to investigate the maturational time course of the occlusion effect in infants with normal hearing. The objectives were (i) to investigate the occlusion effect in ...a larger group of young infants, (ii) to determine whether the occlusion effect is seen in bone conduction auditory steady state responses (ASSRs) for older infants, and (iii) to investigate the mechanisms that underlie bone conduction hearing in unoccluded and occluded ears in infants by measuring sound pressure in the ear canal.
DESIGN:Experiments 1A and 1BThe SPL in the ear canal to 500, 1000, and 2000 Hz bone-conducted pure tones were compared in 22 young infants (0–7 mo), 10 older infants (10–22 mo), and 34 adults, all with normal hearing, for unoccluded and occluded ears. Experiment 2Bone conduction behavioral thresholds in 17 adults were compared for unoccluded and occluded ears at 500, 1000, 2000, and 4000 Hz. Experiment 3Bone conduction ASSR thresholds and amplitudes were compared in 22 young infants, 10 older infants, and 20 adults for an unoccluded and occluded test ear. Stimuli were bone-conducted amplitude/frequency-modulated tones presented simultaneously at 500, 1000, 2000, and 4000 Hz.
RESULTS:There were significant increases in sound pressure in the ear canal for stimuli presented at 40 dB HL when ears were occluded at 500 and 1000 Hz for all age groups. Infants showed the largest increases in SPL at 500 and 1000 Hz (5–8 dB > adults). Young infants showed no significant decreases in ASSR thresholds (2–6 dB) and amplitudes (0–10 nV) across frequency with occlusion; however, a significant number of infants had an occlusion effect at 500 Hz. Older infants showed a nonsignificant decrease in ASSR thresholds with occlusion (8 dB), a significant increase in ASSR amplitudes at 1000 Hz (6–21 nV), and a significant number of infants with an occlusion effect at 1000 Hz. Adult behavioral thresholds decreased significantly when ears were occluded at 500 and 1000 Hz; for ASSRs, thresholds also decreased (6–7 dB) and amplitudes increased (3–11 nV) at both 500 and 1000 Hz, but the mean trends and statistical findings were not in agreement in all cases. A significant number of adult subjects had an occlusion effect at 500 and 1000 Hz for both behavioral and ASSR thresholds.
CONCLUSIONS:Our findings suggest that the occlusion effect for ASSR thresholds in young infants is small but emerging at 500 Hz but negligible at 1000 Hz and that the occlusion effect in older infants is emerging at both 500 and 1000 Hz. The clinical implications of these findings are that it is appropriate to conduct bone conduction testing on young infants without compensating for an occlusion effect; however, for older infants, it is prudent to remove insert earphones during bone conduction testing. For both young and older infants, occluding the ear canal increases the sound pressure near the tympanic membrane; however, this pathway appears to contribute less to bone conduction hearing when ears are occluded compared with adults as measured by ASSRs.
: It is known that Cinnamomum camphora seed oil (CCSO) is rich in medium‐chain fatty acids (MCFAs) or medium‐chain triacylglycerols (MCTs). The purpose of the present study was to produce zero‐trans ...MCTs‐enriched plastic fat from a lipid mixture (500 g) of palm stearin (PS) and CCSO at 3 weight ratios (PS:CCSO 60:40, 70:30, 80:20, wt/wt) by using lipase (Lipozyme TL IM, 10% of total substrate) as a catalyst at 65 °C for 8 h. The major fatty acids of the products were palmitic acid (C16:0, 42.68% to 53.42%), oleic acid (C18:1, 22.41% to 23.46%), and MCFAs (8.67% to 18.73%). Alpha‐tocopherol (0.48 to 2.51 mg/100 g), γ‐tocopherol (1.70 to 3.88 mg/100 g), and δ‐tocopherol (2.08 to 3.95 mg/100 g) were detected in the interesterified products. The physical properties including solid fat content (SFC), slip melting point (SMP), and crystal polymorphism of the products were evaluated for possible application in shortening or margarine. Results showed that the SFCs of interesterified products at 25 °C were 9% (60:40, PS:CCSO), 18.50% (70:30, PS:CCSO), and 29.2% (80:20, PS:CCSO), respectively. The β′ crystal form was found in most of the interesterified products. Furthermore, no trans fatty acids were detected in the products. Such zero‐trans MCT‐enriched fats may have a potential functionality for shortenings and margarines which may become a new type of nutritional plastic fat for daily diet.
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