This study aimed to evaluate the working memory (WM) updating ability of patients with major depressive disorder (MDD) and investigate the potential underlying neuroelectric oscillatory mechanisms. The overall goal was to identify potential biological markers of impaired WM updating function in MDD. 56 patients with MDD and 43 age- and gender-matched healthy controls (HCs) were recruited. All participants underwent clinical evaluations and electroencephalography (EEG) was used to record their brain activity in real time while performing the n-back task (0- and 2-back). Two-way analysis of variance was used to compare the WM behavioral performance and theta (4–8 Hz), alpha (8–13 Hz), and gamma (30–45 Hz) band powers between the two groups. Further, Spearman correlation analysis was performed to examine the relationships between the significant differential oscillation patterns and (1) emotional symptoms and (2) WM performance in the MDD group. Compared to the control group, the MDD group showed poorer accuracy and reaction time in the 2-back task. During the WM encoding phase of the 2-back task, the patient group exhibited decreased parietal theta oscillation activity, which was significantly correlated with lower accuracy and longer reaction times. Additionally, the control group exhibited stronger frontal-midline theta and occipital alpha oscillations during the 2-back task. This distinct pattern of activity as a function of task difficulty was not observed in the MDD group. MDD patients demonstrated impaired WM updating ability, primarily due to abnormalities in the memory encoding phase. The weakened parietal theta oscillation activity and the abnormal patterns of frontal-midline theta and occipital alpha oscillations might constitute the neurophysiological basis of these functional differences.

Major depressive disorder (MDD) often presents alongside physical illnesses, such as a high incidence of subclinical hypothyroidism (SHypo) in patients, highlighting the common occurrence of these comorbidities. Recent research has indicated that the presence of comorbid SHypo in individuals diagnosed with MDD may result in notable alterations in both brain structure and function. This study aimed was to investigate the neurological mechanisms underlying this co-occurrence using a data-driven approach to analyze brain activity patterns. Twenty-nine patients diagnosed with MDD without any comorbid conditions (nSHypo-MDD) were included in the study, along with 29 MDD patients who also had SHypo (SHypo-MDD), 26 patients with SHypo only, and 29 healthy individuals as controls (HCs). Each participant received resting-state functional magnetic resonance imaging scans and underwent neuropsychological evaluations. We found significantly altered functional connectivity (FC) within the resting-state networks (RSNs) of the ventral and dorsal sensorimotor network (VSMN and DSMN) and occipital pole visual network (PVN) (p < 0.05, FDR corrected). A vital interaction effect between SHypo and MDD was detected in the PVN, showing that SHypo-MDD patients had higher FC values in the left cuneus than nSHypo-MDD patients. Serum-free triiodothyronine (FT3) levels in SHypo-MDD patients demonstrated an inverse relationship with FC values of the right supplementary motor area (SMA.R) (r = − 0.563, p = 0.003). Furthermore, the FC values in the left cuneus are positively associated with the Digit Symbol Substitution Test (DSST) scores (r = 0.507, p = 0.008). Our study reveals significant FC changes in SHypo-MDD patients, particularly in the PVN, VSMN, and DSMN, suggesting compensatory mechanisms that mitigate cognitive deficits and highlighting the need for integrated management of SHypo and MDD to improve cognitive outcomes.

Aiming at the current engineering and technical problems such as the complex mathematical form of the isothermal combustion mathematical model in the turbine and the use of more complex entropy for calculation in the model, the isothermal combustion mathematical model in the turbine can be derived from the fundamental thermodynamic process principle of the isothermal process. In this paper, the newly developed mathematical model of isothermal combustion in a turbine is analyzed and compared with the mathematical model from literature, and the feasibility and good applicability of the new model are proved through programming calculation. It is proposed that the newly established mathematical model of isothermal combustion in a turbine can significantly improve the programming efficiency and calculation efficiency. In addition, the new model is applied to the overall thermal performance calculation program of the aero-engine, and the thermal performance analysis of the aero-engine under air cruise conditions is carried out based on the turbine’s internal burner technology. It can be concluded that the turbine’s internal burner technology will significantly improve the thermal performance of the aero-engine, and at the same time, the increment of TSFC can be ignored.

Background: Psychomotor retardation (PMR) is a core feature of major depressive disorder (MDD), which is characterized by abnormalities in motor control and cognitive processes. PMR in MDD can predict a poor antidepressant response, suggesting that PMR may serve as a marker of the antidepressant response. However, the neuropathological relationship between treatment outcomes and PMR remains uncertain. Thus, this study examined electrophysiological biomarkers associated with poor antidepressant response in MDD. Methods: A total of 142 subjects were enrolled in this study, including 49 healthy controls (HCs) and 93 MDD patients. All participants performed a simple right-hand visuomotor task during magnetoencephalography (MEG) scanning. Patients who exhibited at least a 50 % reduction in disorder severity at the endpoint (>2 weeks) were considered to be responders. Motor-related beta desynchronization (MRBD) and inter- and intra-hemispheric functional connectivity were measured in the bilateral motor network. Results: An increased MRBD and decreased inter- and intra-hemispheric functional connectivity in the motor network during movement were observed in non-responders, relative to responders and HCs. This dysregulation predicted the potential antidepressant response. Conclusion: Abnormal local activity and functional connectivity in the motor network indicate poor psychomotor function, which might cause insensitivity to antidepressant treatment. This could be regarded as a potential neural mechanism for the prediction of a patient's treatment response.

Abstract At present, for the research of aero engine performance, it is necessary to calculate the overall thermal performance of the aero engine at the beginning of the research. For the mathematical model of the isentropic expansion (compression) process, most researchers use the ideal state value to calculate in the mathematical model, so that the calculated results have a certain error compared with the actual value. Therefore, the new isentropic expansion (compression) process mathematical model based on the Φ function is applied in this paper to the technical aero engine overall thermal performance calculation. After calculation and analysis, it is concluded that the calculation accuracy of the mathematical model provided in this paper is higher than that of the literature program for the overall thermodynamic performance parameters of the aero engine, whether it is the thrust of the aero engine, the unit fuel efficiency, or the thermal efficiency of the aero engine. It shows that it is feasible to revise and improve the mathematical model of isentropic compression and isentropic expansion process in this paper, more accurate calculation results can be obtained by using the new model in the performance analysis program, and more accurate numerical analysis can be carried out.

High gravity (high-g) combustion can significantly increase flame propagation speed, thereby potentially shortening the axial length of aero-engines and increasing their thrust-to-weight ratio. In this study, we utilized the large eddy simulation model to investigate the combustion characteristics and flame morphology evolution of premixed propane–air flames in a channel with a backward-facing step. The study reveals that both the increase in centrifugal force and flow velocity can enhance pressure fluctuations during combustion and increase the turbulence intensity. The presence of centrifugal force promotes the occurrence of Rayleigh–Taylor instability (RTI) between hot and cold fluids. The combined effects of RTI and Kelvin–Helmholtz instability (KHI) enhance the disturbance between hot and cold fluids, shorten the fuel combustion time, and intensify the dissipation of large-scale vortices. The increase in fluid flow velocity can raise the flame front’s hydrodynamic stretch rate, thereby enhancing the turbulence level during combustion to a certain extent and increasing the fuel consumption rate. When a strong centrifugal force is applied, the global flame propagation speed can be more than doubled. Within a certain range, the increase in high-g field strength can enhance the intensity of RTI and accelerate the transition of RTI to the nonlinear stage.

Laminaria japonica is widely consumed as a key food and medicine. Polysaccharides are one of the most plentiful constituents of this marine plant. In this study, several polysaccharide fractions with different charge numbers were obtained. Their physicochemical properties and anticoagulant activities were determined by chemical and instrumental methods. The chemical analysis showed that Laminaria japonica polysaccharides (LJPs) and the purified fractions LJP0, LJP04, LJP06, and LJP08 mainly consisted of mannose, glucuronic acid, galactose, and fucose in different mole ratios. LJP04 and LJP06 also contained minor amounts of xylose. The polysaccharide fractions eluted by higher concentration of NaCl solutions showed higher contents of uronic acid and sulfate group. Biological activity assays showed that LJPs LJP06 and LJP08 could obviously prolong the activated partial thromboplastin time (APTT), indicating that they had strong anticoagulant activity. Furthermore, we found that LJP06 exerted this activity by inhibiting intrinsic factor Xase with higher selectivity than other fractions, which may have negligible bleeding risk. The sulfate group may play an important role in the anticoagulant activity. In addition, the carboxyl group and surface morphology of these fractions may affect their anticoagulant activities. The results provide information for applications of L. japonica polysaccharides, especially LJP06 as anticoagulants in functional foods and therapeutic agents.

An experimental study was performed on the primary breakup of a liquid sheet in a planar prefilming airblast atomizer. Using a high-speed camera, the backlighting visualization and reflection imaging were applied to record images and capture the breakup process of the liquid film. Image post-processing techniques were developed to obtain the quantitative atomization characteristics, including the surface wave frequency, film thickness, and film breakup length. In particular, the effects of aerodynamic parameters and gravity on atomization were highlighted. The results demonstrated that the aerodynamic parameters had the predominant influence on the atomization performance, whereas the effect of gravity was less important. Based on non-dimensional aerodynamic numbers, the disintegration process of the liquid film on the prefilmer was classified according to three breakup mechanisms. Additionally, correlations were derived from the experimental data and used to predict the atomization characteristics. The fitting offset of the surface wave frequency was limited to 10%, and the breakup length was limited to 15%. These predictive correlations could assist in resolving engineering issues regarding prefilming atomizers.

The shape of circle is one of fundamental geometric primitives of man-made engineering objects. Thus, extraction of circles from scanned point clouds is a quite important task in 3D geometry data processing. However, existing circle extraction methods either are sensitive to the quality of raw point clouds when classifying circle-boundary points, or require well-designed fitting functions when regressing circle parameters. To relieve the challenges, we propose an end-to-end Point Cloud Circle Algebraic Fitting Network (Circle-Net) based on a synergy of deep circle-boundary point feature learning and weighted algebraic fitting. First, we design a circle-boundary learning module, which considers local and global neighboring contexts of each point, to detect all potential circle-boundary points. Second, we develop a deep feature based circle parameter learning module for weighted algebraic fitting, without designing any weight metric, to avoid the influence of outliers during fitting. Unlike most of the cutting-edge circle extraction wisdoms, the proposed classification-and-fitting modules are originally co-trained with a comprehensive loss to enhance the quality of extracted circles.Comparisons on the established dataset and real-scanned point clouds exhibit clear improvements of Circle-Net over SOTAs in terms of both noise-robustness and extraction accuracy. We will release our code, model, and data for both training and evaluation on GitHub upon publication.

BACKGROUND:One devastating outcome of major depressive disorder (MDD) is high suicidality, especially for patients with suicide attempt (SA). Evidence indicated that SA may be strongly associated with inhibitory control deficits. We hypothesized that the inhibition function deficits of patient with SA might be underpinned by abnormal neuronal oscillations.METHODS:Our study recruited 111 subjects including 74 patients and 37 controls, who performed a GO/NOGO task during magnetoencephalography recording. Time-frequency-representations and phase-amplitude-coupling were measured for the brain circuits involved in the inhibitory function. Phase-slope-indexes were calculated between regions to determine the direction of power flow.RESULTS:Significant increased reaction time and decreased judgment accuracy were observed in SA group. During the perception stage of GO task (approximately 125 ms), SA group manifested elevated alpha power in ventral prefrontal cortex (VPFC) and attenuated beta power in dorsal anterior cingulate (dACC) compared with other groups (p < 0.01). In the processing stage of NOGO task (approximately 300 ms), they showed decreased beta power in VPFC and increased alpha power in dACC (p < 0.01). Alpha-beta decoupling during both tasks was observed in SA group. Furthermore, the decoupling from VPFC to dACC under NOGO tasks was significantly correlated with suicide risk level.LIMITATIONS:The number of participants was relatively small, and psychological elements were not involved in current study.CONCLUSION:Dysregulated oscillatory activities of dACC and VPFC suggested deficits in execution and inhibition functions triggering high suicide risks. The alpha-beta decoupling from VPFC to dACC could be served as a neuro-electrophysiological biomarker for identifying potential suicide risk.

Li-ion batteries are widely used in electric vehicles for their superior performance. To investigate a simple and efficient method for the Li-ion power batteries, the cold plate with four types of structures A, B, C, and D were established, respectively. Subsequently, the effects of micro-channel thickness and width on the cooling performance of battery thermal management systems were analyzed by using a numerical simulation method. The results show that with the increases of the micro-channel thickness, the maximum temperature (Tmax) of the cold plate is gradually increased under structures A, B, and C, while it is gradually decreased under structure D. The standard deviation of temperature (T?) of the cold plate of structure A was less affected by the change of the micro-channel thickness. Under structures B, C, and D, the temperature uniformity of the cold plate can be well maintained when the micro-channel thickness was 1.0 [mm]. With the increase of the micro-channel width, the Tmax and T? of the cold plate are gradually increased in all cases, while the ?P from the inlet to outlet is gradually decreased. The temperature uniformity of the cold plate is well maintained by structure C. The decreasing amount and changing range of ?P caused by the change of micro-channel width is smaller than caused by the change of the thickness.

A numerical study was conducted to verify and validate a new solver, named hyperReactingSodFoam, based on the OpenFOAM toolbox. This study mainly focuses on verification of solver’s computational capability to compute hypersonic flows involving shock-induced combustion, and its applications. This investigation is limited to inviscid flow and incorporates Minmod limiter to achieve total variation diminishing property. Analysis of a practical case was conducted by simulate and validate hypersonic blunt body projectile experiments at Mach 6.46 and 4.18. Likewise, to demonstrate the wider applicability of solver, a standing detonation in an oblique detonation wave engine combustor with a sharp as well as a blunted wedge geometry was studied. It was observed that, for a given flow condition and combustor geometry, a sharp wedge has a better mass-weighted average pressure recovery comparative to the blunted wedge. However, blunted wedge geometry provides a better picture of the detonation phenomenon as a practical wedge will have finite bluntness. In addition, the concept of the detonation induction length becomes less relevant for a blunted wedge.

Background Recent attention has focused on the role of rumination in suicidality, with evidence indicating that rumination may be positively related to suicidal ideation. There remains disagreement on the nature of the relationship between rumination and suicide attempts, especially in major affective disorders. This study was designed to identify whether rumination is a risk factor for attempted suicide. Methods A total of 309 patients with major depressive episodes were recruited for this study, including 170 patients with major depression and 139 patients with bipolar disorder. All participants were categorized into two groups based on a series of clinical assessments: suicide attempters ( n = 87) and non-suicide attempters ( n = 222). Rumination was evaluated with the Ruminative Responses Scale. A binary logistic regression analysis was carried out to evaluate the relationship between rumination and suicide attempts. Results Both global ruminative levels and the two subtypes of rumination, brooding and reflection, were significantly higher in the suicide attempters than the non-suicide attempters. After controlling for age, current depression and anxiety symptoms, and episode frequency, it was found that global rumination and reflection (but not brooding) were positively associated with suicide attempts. Conclusion These results suggest that rumination may be a risk factor for suicide attempts and highlight the maladaptive nature of reflection in patients with major depressive episodes.

In this study, carbon foam (CF) and SiO2 aerogel composite were prepared by the sol–gel method under a circumstance of the atmospheric drying process. The Pyrolysis mechanism of carbon foam was investigated through thermal gravimetric analysis and Fourier transform infrared spectroscopy (FTIR). Carbon foam having ultralight properties with a density of 5.44 kg/m3, functions as a skeleton to support the composite. The maximum compressive stress measured for CF/SiO2 aerogel composite was about 1.0 MPa. At room temperature, the measured thermal conductivities of the CF and CF/SiO2 aerogel composite were 0.035 W/m K and 0.024 W/m K, while at 300 °C, it was reported to be 0.120 W/m K and 0.057 W/m K. Aerogel filled in carbon foam cells have significantly reduced the gaseous thermal conductivity of the prepared composite.

为了改善热电元件的工作性能,提出了两种新型结构的热电元件,分别是半倾斜型和双倾斜型,倾斜角度57.99°.参考传统的垂直型热电元件,采用数值模拟的方法,通过控制电流、热端温度和冷热端温差等参量,对三种结构的热电元件进行了温度场、电场耦合分析.结果显示:双倾斜型电热元件能够实现最低的冷端温度,且随着电流的增大,不同结构冷端温度的差值先增大后减小;在小功率条件下,双倾斜型电热元件制冷量最大;双倾斜结构能够达到最高的制冷系数,但在大功率条件下制冷系数却最低;倾角为钝角处存在场强突变现象;最大电流密度均出现在不与半导体接触的铜片区域中;双倾斜结构更适用于微小型低功耗热电设备.

利用二维非稳态无黏可压欧拉方程模拟得到了能够稳定自持的斜爆震波(ODW)结构,在某时刻从进口边界施加一温度的瞬间变化(分别为下降100 K、上升100 K),从而得到一次温度扰动.模拟结果表明,ODW结构能够顺利过渡,但扰动传播过后,ODW的内部不稳定性被进一步被释放,胞格结构更加清晰;结合定量和定性分析发现,扰动主要以激波、膨胀波和弱压缩波3种形式在燃烧室内传播;对比2种扰动下的结果得出,3种波在爆震区内传播过程中的位置分布相同,但在爆燃区内却完全相反,造成这种结果的主要原因是2种扰动引发的弱压缩波的强度不同,从而对ODW结构调整所起到的作用也存在很大区别;在温降扰动下,3种波沿壁面向下游传播,其中激波会呈现出弓形激波、马赫反射、规则反射和近乎垂直于壁面的正激波4种形态,而在温升扰动下,3种波沿ODW面向下游传播,传播形态也较为稳定.

为了提高资源的有效利用率,对燃气灶等设备进行废热回收,提出一种温差发电模型.运用FLUENT软件对该发电装置的温度场、流场进行了三维仿真计算.研究热端设置成格栅结构、热端与水平面的倾斜角大小对余热回收效率的影响.结果表明:将热端设计成格栅结构可以有效提高其辐射温度,改变热端与水平面的倾斜角可以将冷热端温差最高提升57％,进而可以提高温差发电装置的热效率.

采用两大类模型,对应用射流涡流燃烧结构方案的高压涡轮导向器性能进行数值模拟研究.利用基于压力的隐式稳态求解器以及尺度适应模拟湍流模型(SAS),完成了涡轮内增燃燃烧室内的流动与燃烧过程的数值模拟.研究结果表明:无论是在高压涡轮导向器顶部还是在底部耦合驻涡凹腔,对导向器叶间流场形态、流体流动转折角、导向器叶间静压力场的形态以及分布、总压损失均无明显影响,维持了原有导向器的基本性能;高压涡轮导向器耦合射流涡流燃烧结构,增加了涡轮叶片叶间的平均温度以及涡轮导向器出口的平均温度.

The influence of the flow rate change of the secondary jet and the change of environmental pres-sure on turbine inter-vane burner based on jet-vortex flow was studied.In this case,the environmental pres-sure remained unchanged when the secondary jet flow changed.When the environmental pressure changed, the secondary jet flow rate remained unchanged at 0.014 kg/s.The flow and combustion process of the com-bustion chamber in the turbine was simulated by using the pressure based implicit steady-state solver,and the scale adaptive simulation turbulence model(SAS)was applied in the numerical simulation.The results show that with the increase of secondary jet flow,the temperature distribution in the jet vortex combustion chamber is homogeneous, the total pressure loss and combustion efficiency increases, and the pollutant is reduced.With the increase of environmental pressure,the temperature distribution of jet vortex combustion chamber is not affected, but the total pressure loss is reduced, combustion efficiency is increased, and the pollutant is reduced.

为了探讨空调服系统的流动与换热规律,基于人体外形创建了体表-服装几何模型.采用数值仿真的方法研究了横向型管路系统的流动分配特征,探讨了体表平均温度、内外温差关于入口速度、入口温度的变化关系.结果显示:管路质量流量分配存在突变现象;体表上半部分温度低于下半部分温度;体表平均温度、内外温差与入口速度成二次函数关系,与入口温度成线性关系;入口温度每升高1℃,体表平均温度升高0.34℃,而内外温差降低0.33℃.