Noise-induced hippocampal damage: potential mechanisms

Aim and Objective: The Dendrobium officinalis flower (DOF) is popular in China due to common belief in its anti-aging properties and positive effects on “nourish yin”. However, there have been relatively few confirmatory pharmacological experiments conducted to date. The aim of this work was to evaluate whether DOF has beneficial effects on learning and memory in senescent rats, and, if so, to determine its potential mechanism of effect. Materials and Methods: SD rats were administrated orally DOF at a dose of 1.38, or 0.46 g/kg once a day for 8 weeks. Two other groups included a healthy untreated control group and a senescent control group. During the 7th week, a Morris water maze test was performed to assess learning and memory. At the end of the experiment, serum and brain samples were collected to measure concentrations of antioxidant enzymes, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GSH-Px) in serum, and the neurotransmitters, including γ-aminobutyric acid (γ-GABA), Glutamic (Glu), and monoamine oxidase B (MAO-B) in the brain. Histopathology of the hippocampus was assessed using hematoxylin-eosin (H&E) staining. Results: The results suggested that treatment with DOF improved learning as measured by escape latency, total distance, and target quadrant time, and also increased levels of γ-GABA in the brain. In addition, DOF decreased the levels of MDA, Glu, and MAO-B, and improved SOD and GSHPx. Histopathological analysis showed that DOF also significantly reduced structural lesions and neurodegeneration in the hippocampus relative to untreated senescent rats. Conclusion: DOF alleviated brain aging and improved the spatial learning abilities in senescent rats, potentially by attenuating oxidative stress and thus reducing hippocampal damage and balancing the release of neurotransmitters.

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Effects of Fling Step and Forward Directivity on Seismic Response of Buildings

Earthquake Spectra ◽

10.1193/1.2192560 ◽

2006 ◽

Vol 22 (2) ◽

pp. 367-390 ◽

Cited By ~ 255

Author(s):

Erol Kalkan ◽

Sashi K. Kunnath

Keyword(s):

Seismic Response ◽

Ground Motions ◽

High Amplitude ◽

Moment Frames ◽

Steel Moment Frames ◽

Damage Potential ◽

Near Fault ◽

Forward Directivity ◽

Fling Step ◽

Far Fault

This paper investigates the consequences of well-known characteristics of near-fault ground motions on the seismic response of steel moment frames. Additionally, idealized pulses are utilized in a separate study to gain further insight into the effects of high-amplitude pulses on structural demands. Simple input pulses were also synthesized to simulate artificial fling-step effects in ground motions originally having forward directivity. Findings from the study reveal that median maximum demands and the dispersion in the peak values were higher for near-fault records than far-fault motions. The arrival of the velocity pulse in a near-fault record causes the structure to dissipate considerable input energy in relatively few plastic cycles, whereas cumulative effects from increased cyclic demands are more pronounced in far-fault records. For pulse-type input, the maximum demand is a function of the ratio of the pulse period to the fundamental period of the structure. Records with fling effects were found to excite systems primarily in their fundamental mode while waveforms with forward directivity in the absence of fling caused higher modes to be activated. It is concluded that the acceleration and velocity spectra, when examined collectively, can be utilized to reasonably assess the damage potential of near-fault records.

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Rutting and moisture-induced damage potential of foamed warm mix asphalt (WMA) containing RAP

Innovative Infrastructure Solutions ◽

10.1007/s41062-021-00528-7 ◽

2021 ◽

Vol 6 (3) ◽

Author(s):

Mohammad Ashiqur Rahman ◽

Rouzbeh Ghabchi ◽

Musharraf Zaman ◽

Syed Ashik Ali

Keyword(s):

Asphalt Pavement ◽

Warm Mix Asphalt ◽

Environmental Benefits ◽

Reclaimed Asphalt Pavement ◽

Chemical Additives ◽

Flow Number ◽

Damage Potential ◽

Asphalt Mixes ◽

Reclaimed Asphalt ◽

Wheel Tracking

AbstractDespite significant economic and environmental benefits, performance of warm mix asphalt (WMA) containing reclaimed asphalt pavement (RAP) remains a matter of concern. Among the current WMA technologies, the plant foaming technique (called “foamed WMA” in this study) has gained the most attention, since it eliminates the need for chemical additives. In the present study, the laboratory performance, namely rutting and moisture-induced damage potential of foamed WMA containing RAP were evaluated and compared with those of similar hot mix asphalt (HMA) containing identical amount of RAP. Dynamic modulus, Hamburg wheel tracking (HWT) and flow number tests were performed to assess the rutting resistance of the mixes. Also, stripping inflection point from HWT tests and tensile strength ratio after AASHTO T 283 and moisture induced sensitivity test (MIST) conditioning were used to evaluate the moisture-induced damage of asphalt mixes. It was found that MIST conditioning effectively simulates the moisture-induced damage and can capture the propensity of asphalt mixes to moisture damage more distinctly compared to AASHTO T 283 method due to application of cyclic loadings. The foamed WMA was found to exhibit higher rutting and moisture-induced damage potential due to lower mixing and compaction temperatures compared to HMA. However, the increase in RAP content was found to reduce rutting and moisture-induced damage potential for WMA. Therefore, the lower stiffness of foamed WMA may be compensated with the addition of stiffer binder from RAP.

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Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽

10.3390/photonics8040107 ◽

2021 ◽

Vol 8 (4) ◽

pp. 107

Author(s):

Haichao Yu ◽

Feng Tang ◽

Jingjun Wu ◽

Zao Yi ◽

Xin Ye ◽

...

Keyword(s):

Electric Field ◽

Electric Fields ◽

Laser Cutting ◽

High Complexity ◽

Damage Potential ◽

Optical Components ◽

Nanohole Arrays ◽

Intense Light ◽

Polarization Of Light ◽

Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

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Tannin-Mordant Coloration with Matcha (camelia sinensis) and Iron(II)-Lactate on Human Hair Tresses

Molecules ◽

10.3390/molecules26040829 ◽

2021 ◽

Vol 26 (4) ◽

pp. 829

Author(s):

Lusine Sargsyan ◽

Thomas Hippe ◽

Hartmut Manneck ◽

Volkmar Vill

Keyword(s):

Human Hair ◽

Cysteic Acid ◽

Damage Potential ◽

Natural Hair ◽

Wash Fastness ◽

Dyeing Method ◽

Mordant Dyeing ◽

Concentration Limits

The aim of this work was to optimize our natural hair dyeing system which we described in our previous work and to compare with other dyeing systems. Therefore, we investigated concentration limits of matcha and mordant and compared this new dyeing method with commercial permanent systems on the market. Completely unpigmented hair tresses were dyed with matcha powder (camelia sinensis) and iron(II)-lactate. To investigate the wash fastness and concentration limits, the differently dyed hair tresses were spectrophotometrically measured. The comparison of the damage potential for which cysteic acid is an indicator was measured by NIR. The concentration of matcha and mordant are responsible for the intensity of the color results. The higher the matcha or the mordant concentration, the darker the color results of the dyed hair tresses. Hair damage of matcha mordant dyeing is comparable with results of commercial permanent hair coloration systems. Moreover, the results of wash fastness of matcha mordant dyed hair tresses is comparable and even better by tendency to permanent colored hair tresses.

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