Introduction Alzheimer's disease (AD) is the most common progressive neurodegenerative disease for which there is no cure. Recent studies have shown a close link between type 2 diabetes and AD, which suggested that drugs for type 2 diabetes may be effective for AD. GLP‐1 and GIP are incretin hormones that can ameliorate diabetes. Methods In the present study, we tested the novel dual GLP‐1/GIP receptor agonist DA5‐CH in the icv. streptozotocin (STZ)‐induced insulin desensitization model of AD in rats to explore the protective effects of DA5‐CH. Results The results show that DA5‐CH could reverse the STZ‐induced working memory impairments in a Y‐maze tests, and spatial memory impairments in the water maze task, and decrease the levels of phosphorylated tauS396 protein in the hippocampus. In EEG recordings, STZ treatment diminished the power of the theta band frequency. DA5‐CH was able to increase the energy of theta band activity in the hippocampal CA1 region. The drug also increased the expression of synapse‐related proteins in the hippocampus. After DA5‐CH treatment, mitochondrial stress was alleviated as shown by the improved ratio of Bax/Bcl‐2 in the hippocampus. Growth factor signaling was also normalized as shown by the increased level of the transcription factor P‐CREBS133. In addition, we were able to show that DA5‐CH can cross the blood–brain barrier at an increased rate compared with other dual GLP‐1/GIP or single GLP‐1 receptor agonists. Conclusion Therefore, our results demonstrate that DA5‐CH has neuroprotective effects in the STZ‐induced animal model and that DA5‐CH has potential to treat neurodegenerative disorders such as AD.

MXenes, as a legendary family of 2D van der Waals nanosheets materials, are extensively studied due to their unique characteristics of broadband nonlinear optical response. In particular, MXenes have excellent nonlinear optical properties of very large nonlinear absorption coefficients and very large nonlinear refractive indexes, which have attracted people's great attentions to study the application of MXenes in photonics, electronics, and optoelectronics in recent years. However, the high‐repetition‐rate (HRR) ultrafast pulses are not explored based on these kinds of materials. MXene Ti3C2Tx saturable absorber (SA) based on micro‐fiber is fabricated by optical deposition method. Here, MXene Ti3C2Tx SA is used to achieve 36th harmonic mode‐locking with a repetition rate of 218.4 MHz, a central wavelength of 1566.9 nm, the pulse width of 850 fs, and the spectral width of 3.51 nm. The maximum average output power and pulse energy are 6.95 mW and 0.032 nJ, respectively. This research based on MXene Ti3C2Tx light modulator opens a bright avenue for advanced nonlinear photonics.

An all-fiber multiwavelength Tm-doped laser assisted by four-wave mixing (FWM) in highly Germania-doped highly nonlinear fiber (HG-HNLF) has been experimentally demonstrated. Benefiting from the high nonlinearity of the HG-HNLF, intensity-dependent gain caused by FWM is introduced into the laser cavity to mitigate the gain competition in Tm-doped fiber. Thanks to a 50-m HG-HNLF, 9, 22, and 36 lasing lines with considering 10-dB, 20-dB, and 30-dB bandwidth, respectively is obtained at room temperature with wavelength spacing of 0.86 nm. More than 30-nm broad-band lasing can be obtained. The stability of the proposed fiber laser has also been studied. Repeat measurements show the power fluctuations and wavelength drifts of the lasing lines are less than 1.6 dB and 0.05 nm, respectively. The laser performances without the assistance of HG-HNLF have fewer center wavelengths lasing, which indicates that FWM in HG-HNLF plays an important role for the multiwavelength laser operation.

This paper reports the use of the Ar branching ratio as an alternative means of calibrating the relative spectral response of a spectrometer/detector apparatus, with emphasis on its use in Laser Induced Breakdown Spectroscopy (LIBS) diagnostic experiments. The method is compared to the more conventional calibration routine using standard lamps. The argon method was implemented with an Ar-filled hollow cathode lamp and with a LIBS plasma in argon at different pressures. For the conventional calibration, a quartz tungsten halogen (QTH) lamp available in our laboratory has been used as a standard of spectral irradiance. The results obtained with the three methods are compared and discussed. It is shown that the spectral response data agree well with each other above 350 nm. At lower wavelengths, the data differ significantly. It is believed that this is due to the degradation of the calibration values of the lamp, which was not re-calibrated in a long time. It is concluded that the Ar-branching ratio method is a useful calibration technique for use with LIBS plasma diagnostic experiments.