Repetitive traumatic brain injury–induced complement C1–related inflammation impairs long-term hippocampal neurogenesis

Repetitive traumatic brain injury impacts adult neurogenesis in the hippocampal dentate gyrus,leading to long-term cognitive impairment.However,the mechanism underlying this neurogenesis impairment remains unknown.In this study,we established a male mouse model of repetitive traumatic brain injury and performed long-term evaluation of neurogenesis of the hippocampal dentate gyrus after repetitive traumatic brain injury.Our results showed that repetitive traumatic brain injury inhibited neural stem cell proliferation and development,delayed neuronal maturation,and reduced the complexity of neuronal dendrites and spines.Mice with repetitive traumatic brain injuryalso showed deficits in spatial memory retrieval.Moreover,following repetitive traumatic brain injury,neuroinflammation was enhanced in the neurogenesis microenvironment where C1q levels were increased,C1q binding protein levels were decreased,and canonical Wnt/β-catenin signaling was downregulated.An inhibitor of C1 reversed the long-term impairment of neurogenesis induced by repetitive traumatic brain injury and improved neurological function.These findings suggest that repetitive traumatic brain injury–induced C1-related inflammation impairs long-term neurogenesis in the dentate gyrus and contributes to spatial memory retrieval dysfunction.

RESPONSE OF PARAMETRICALLY EXCITED DUFFING-VAN DER POL OSCILLATOR WITH DELAYED FEEDBACK

The dynamical behaviour of a parametrically excited Duffing-van der Pol oscillator under linear-plus-nonlinear state feedback control with a time delay is concerned. By means of the method of averaging together with truncation of Taylor expansions, two slow-flow equations on the amplitude and phase of response were derived for the case of principal parametric resonance, it is shown that the stability condition for the trivial solution is only associated with the linear terms in the original systems besides the amplitude and frequency of parametric excitation. And the trivial solution can be stabilized by appreciate choice of gains and time delay in feedback control. Different from the case of the trivial solution, the stability condition for nontrivial solutions is also associated with nonlinear terms besides linear terms in the original system. It is demonstrated that nontrivial steady state responses may lose their stability by saddle-node （SN） or Hopf bifurcation （HB） as parameters vary. The simulations, obtained by numerically integrating the original system, are in good agreement with the analytical results.

Robotic-vs laparoscopic-assisted proctectomy for locally advanced rectal cancer based on propensity score matching: Short-term outcomes at a colorectal center in China

BACKGROUND Reports in the field of robotic surgery for rectal cancer are increasing year by year.However,most of these studies enroll patients at a relatively early stage and have small sample sizes.In fact,studies only on patients with locally advanced rectal cancer(LARC)and with relatively large sample sizes are lacking.AIM To investigate whether the short-term outcomes differed between robotic-assisted proctectomy(RAP)and laparoscopic-assisted proctectomy(LAP)for LARC.METHODS The clinicopathological data of patients with LARC who underwent robotic-or laparoscopic-assisted radical surgery between January 2015 and October 2019 were collected retrospectively.To reduce patient selection bias,we used the clinical baseline characteristics of the two groups of patients as covariates for propensity-score matching(PSM)analysis.Short-term outcomes were compared between the two groups.RESULTS The clinical features were well matched in the PSM cohort.Compared with the LAP group,the RAP group had less intraoperative blood loss,lower volume of pelvic cavity drainage,less time to remove the pelvic drainage tube and urinary catheter,longer distal resection margin and lower rates of conversion(P<0.05).However,the time to recover bowel function,the harvested lymph nodes,the postoperative length of hospital stay,and the rate of unplanned readmission within 30 days postoperatively showed no difference between the two groups(P>0.05).The rates of total complications and all individual complications were similar between the RAP and LAP groups(P>0.05).CONCLUSION This retrospective study indicated that RAP is a safe and feasible method for LARC with better short-term outcomes than LAP,but we have to admit that the clinically significant of part of indicators are relatively small in the practical situation.

Absorption Spectrum Studies on the RDX Crystals with Different Granularity in Terahertz Frequency Range

The absorption spectrum of the cyclotrime-thylenetrinitramine （RDX） with four different particle sizes are measured in the frequency range from 0.1THz to 2.5THz by using the terahertz time-domain spectroscopy （THz-TDS）, and the characteristic absorption peaks are acquired. All the samples are measured in a loose condition, which is very close to the real using environment of the RDX. The results show that the four kinds of samples have similar absorption peaks around the frequency of 0.82THz, 1.05 THz, 1.30THz, 1.46THz, 1.65THz, and 1.95THz. The sample with a large particle size obtains more peaks than the small one, while the peaks obtained from the sample with a small size are more protrudent. The reasons for these differences can be the refraction, scattering, and attenuation of the terahertz wave when it passes through the crystal samples. The theoretical terahertz spectrum of RDX was simulated by using density functional calculations, in which, the Becke ＆amp; Perdew-Wang＇s functional is used in a double numerical plus polarization method （BP/DNP）. Good agreements between the experimental and computed results show that the three peaks located in the frequency of 1.30THz, 1.48THz, and 1.96THz are caused respectively by the twisting of three-nitrogen heterocyclic, the symmetrical oscillations of the double nitro groups, and the oscillations of a single nitro group.

Direction of arrival estimation and signal recovery based on single snapshot compressed sensing in frequency domain

Direction of arrival （DOA） estimation and signal recovery is the base of the under- water target localization, tracking and recognition. Based on the compressed sensing theory, a method for DOA estimation and source signal recovery is proposed using the single snap- shot processing of the received array signal in frequency domain. The received array signal are transformed to frequency domain, and the single snapshot data in frequency domain are re- garded as the measured data of the compressed sensing. According to the frequency, searching orientation and array manifold, the overcomplete array manifold is constructed as the sensing matrix of the compressed sensing. Both the target signal and power of the searching orientation are estimated by the basis pursuit method to complete DOA estimation and signal recovery. Simulation results show that the proposed method has a number of advantages over the mini- mum variance distortionless response （MVDR） method, including improved robustness to noise, fewer requirement in number of sensors and snapshots. And the correlation coefficient of the signal reaches up to 0.89. Experiment results in real environments verify that the proposed method performs more effectively in the detection of weak targets than the MVDR method and can be applied to real sonar system.

Direction of arrival estimation for underwater acoustic target based on compressed sensing after blind reconstruction of array signal in frequency domain

The performance of direction of arrival(DOA)estimation based on compressed sensing(CS)decreases in the complex ocean marine environment.In order to tackle this problem,a method of DOA estimation for underwater acoustic target based on CS after blind reconstruction of array signal in frequency domain is proposed.Firstly,the received array data are transformed to frequency domain by Fourier transform and frequency domain wideband signal are divided into part overlapping multiple sub-band array signal.Secondly,each subband array signal are separated using plural blind source separation(BSS)method,the sub-band separated matrix and target signal can be estimated.Thirdly,the array signal in frequency domain are reconstructed according to the separated matrix and separated signals which were not noises.Fourthly,the sub-band spatial spectrum corresponding to the reconstructed array signal is obtained by CS beamforming method.Finally,the total spatial spectrum is achieved by summing the all sub-band spatial spectrum.And the target direction can be estimated by searching the peak value of the total spatial spectrum.The verification results of simulator data and sea measured data show that,under the same conditions,the target detection ability and direction precision of the proposed method is superior to the classical minimum variance distortionless response(MVDR)method,frequency domain CS method,BSS combined with MVDR method.The spatial spectrum energy of faint target signal is improved obviously,and the ability of the sonar to detect faint target is enhanced.

Tensor feature extraction of underwater passive sonar target based on auditory model

Feature extraction is a key step for underwater passive sonar target classification and recognition.A kind of tensor feature extraction method based on auditory PattersonHoldsworth cochlear model is proposed.First,the filter impulse response of the cochlear model is regarded as the basis function of signal decomposition,and the center frequency of different channels is determined according to the nonlinear scale or conventional linear scale of the auditory model.Then,the gain and bandwidth of the corresponding channel are calculated,and the order and phase parameters of the impulse response are quantified to obtain a relatively complete signal decomposition basis.And according to the principle of signal decomposition,the third-order tensor features of channel number-order number-phase number are obtained.Finally,the classification and recognition of the underwater passive sonar target is realized by calculating the similarity between the testing sample tensor feature and training sample tensor feature.The experiment on passive sonar target classification and recognition shows that the extracted tensor features have better classification and recognition performance,and the equivalent rectangular bandwidth scale of the auditory model is better than the linear scale to divide the center frequency,which can improve the target indication ability of passive sonar.