Reduced Brain Activity in the Right Putamen as an Early Predictor for Treatment Response in Drug-Naive, First-Episode Schizophrenia

Antipsychotic medications can have a significant effect on brain function after only several days of treatment. It is unclear whether such an acute effect can serve as an early predictor for treatment response in schizophrenia. Thirty-two patients with drug-naive, first-episode schizophrenia and 32 healthy controls underwent resting-state functional magnetic resonance imaging. Patients were treated with olanzapine and were scanned at baseline and 1 week of treatment. Healthy controls were scanned once at baseline. Symptom severity was assessed within the patient group using the Positive and Negative Syndrome Scale (PANSS) at three time points (baseline, 1 week of treatment, and 8 weeks of treatment). The fractional amplitude of low frequency fluctuation (fALFF) and support vector regression (SVR) methods were used to analyze the data. Compared with the control group, the patient group showed increased levels of fALFF in the bilateral putamen at baseline. After 1 week of olanzapine treatment, the patient group showed decreased levels of fALFF in the right putamen relative to those at baseline. The SVR analysis found a significantly positive relationship between the reduction in fALFF after 1 week of treatment and the improvement in positive symptoms after 8 weeks of treatment (r = 0.431, p = 0.014). The present study provides evidence that early reduction and normalization of fALFF in the right putamen may serve as a predictor for treatment response in patients with schizophrenia

Risk Coupling Analysis of Deep Foundation Pits Adjacent to Existing Underpass Tunnels Based on Dynamic Bayesian Network and N–K Model

Because deep foundation pits and tunnels are deformation-sensitive structures, the safety of these projects is generally affected by coupled risks. In deep foundation pit construction, if the existing tunnel structure adjacent to the deposit is damaged, it can produce a severe group disaster. It is necessary to identify an efficient risk analysis model to study the dynamic coupled risk of deep foundation pit projects adjacent to existing underpass tunnels and to analyze the risk evolution law to achieve effective real-time safety control. This study proposes a coupled risk analysis model using the N–K model and dynamic Bayesian network to construct deep foundation pits in adjacent existing underpass tunnels. The model is predicated on association rules to explore the interrelationship between risk factors to build a dynamic Bayesian network structure. In addition, the N–K model is utilized to quantify coupled risks under such complex working conditions and to optimize the dynamic Bayesian network structure. The developed model clarifies the risk coupling mechanism of deep foundation pit construction adjacent to an existing underpass tunnel, finds the critical points in the risk transfer process, and conducts dynamic risk prediction and accident causation diagnosis for the coupled risk to realize the dynamic control of the coupled risk in the adjacent existing underpass tunnel construction. Taking the Nanning underground comprehensive utilization project as an example, the validity and applicability of the proposed approach were tested. The results showed that the model is feasible and has application potential, providing effective decision support for safety control while constructing deep foundation pits adjacent to existing tunnels

Sensible heat discharging from pavements with varying thermophysical properties

© 2018 Elsevier Ltd A large portion of the solar absorption of traditional pavements is discharged as sensible heat to the above air and contributes to the formation of urban heat island. The amount of the sensible heat depends on pavement surface-layer thermophysical properties including thermal conductivity, density, heat capacity, surface\u27s emissivity, and albedo. To sort out the influences of these factors in order, this study develops a new simplified theoretical formula to estimate the instantaneous sensible heat flux and the daily accumulative sensible heat from pavements with varying thermal properties. Both the theoretical formula and the numerical results reveal that raising the thermal conductivity, density, or heat capacity of the pavement or increasing them simultaneously decreases the sensible heat but the decreasing rate is negligibly small compared to the amount of the sensible heat. A greater amount of pavement-rejecting sensible heat could be reduced by increasing the surface-layer emissivity. But most traditional pavements have a high emissivity of 0.80–0.95 already so there is a tiny space to vary the pavement\u27s emissivity for curbing the sensible heat. The most effective way to curtailing the pavement-rejected sensible heat is to make the pavement surface highly reflective

Experimental study on darkening water-rich mud tailings for accelerating desiccation

Accelerating natural desiccation of water-rich mud tailings deposited in a large open area reduces the impacts and risks of tailing consolidation to the environment and engineering structures. A simple method for accelerating natural desiccation of mud tailings is to reduce the tailings’ surface albedo, which however has not been confirmed yet. Here we measure the evaporation of water-rich mud tailings with different albedos, and quantify the shrinkage cracks of these tailings via image processing. Three limited-extent mud tailings samples are prepared, in which one is painted black, the other is painted white, and the resting one is unpainted (original orange color). The results show that lowering the albedo of tailings speeds up the evaporation and desiccation of the tailings greatly. The water content of the black tailings drops from 250% to 10% needs about 6 days, which is 2.5 and 4.5 days before those of the orange one and white one, respectively. The surface shrinkage cracks of the tailings reveal that both the black and original tailings share the same crack pattern, suggesting that the albedo acts the secondary role on the crack pattern. Our findings substantiate that darkening the tailings helps desiccate water-rich mud tailings but does not vary the crack pattern for land reclamations of such tailings

Analysis of Engineering Characteristics and Microscopic Mechanism of Red Mud–Bauxite Tailings Mud Foam Light Soil

In order to effectively utilize aluminum industrial waste—red mud and bauxite tailings mud—and reduce the adverse impact of waste on the environment and occupation of land resources, a red mud–bauxite tailings mud foam lightweight soil was developed based on the existing research results. Experiments were conducted to investigate the mechanical properties and microscopic characteristics of the developed materials with different proportions of red mud and bauxite tailings mud. Results show that with the increase in red mud content, the wet density and fluidity of the synthetic sample was increased. With 16% red mud content, the water stability coefficient of the synthetic sample reached its maximum of 0.826, as well as the unconfined compressive strength (UCS) of the sample cured for 28 d (1.056 MPa). SEM images reveal that some wastes of the sample without red mud were agglomerated, the peripheral hydration products were less wrapped, and when the amount of red mud was 16%, the hydration products tightly wrapped the waste particles and increased the structural compactness. The final concentration of alkali leaching of samples increased with the addition of red mud. The maximum concentration of alkali leaching was 384 mg/L for the group with the addition of red mud of 16%. Based on the obtained mechanical strength and alkali release analysis, the sample B24R16 was selected as the optimum among all tested groups. This study explored a way to reuse aluminum industrial waste, and the results are expected to be applied to roadbed and mining filling

Reuse of Red Mud and Bauxite Tailings Mud as Subgrade Materials from the Perspective of Mechanical Properties

In order to reuse red mud and bauxite tailings mud (two typical aluminum industrial wastes) to reduce the occupation of land resources and environmental damage, these two wastes were combined to develop subgrade materials for the first time. With different combinations, the effects of the amounts of red mud, tailings mud, and cementitious materials on the strength of tested subgrade materials were investigated. The mechanism of strength growth was analyzed by a micro-test. The test results showed that the material strength of three combinations met the requirements when the unconfined compression strength (UCS) of all combinations increased with age. The UCS of the A1BC2 combination (the mass ratio of red mud and tailings mud was 2:1, the mass ratio of cement and quicklime was 1:1, and the mass ratio of waste and cementitious materials was 1:0.2) was the best, with the UCS being 3.03 MPa in 7 days. Microscopic imaging showed that specimens with high red mud contents had compact structures without cracks. The strength of these materials is mainly due to hydration reactions and pozzolanic reactions; the cementitious products generated by the reactions solidify Na+ and inhibit the release of OH−, while the addition of tailings mud can reduce the content of Na2O in the material, which makes the environmental compatibility of the A3BC2 combination the best (the mass ratio of red mud and tailings mud was 1:2, the mass ratio of cement and quicklime was 1:1, and the mass ratio of waste and cementitious materials was 1:0.2). Its pH value was 8.75. This experiment verifies the feasibility of the combined application of red mud and tailings mud in subgrade materials. To this end, a feasible scheme for the simultaneous consumption of these two kinds of aluminum industrial wastes has been proposed

Research on the Analytical Conversion Method of Q-s Curves for Self-Balanced Test Piles in Layered Soils

An analytical conversion method was developed for the self-balanced test results of monopile bearing capacity in layered soils to realize the better applicability of the self-balanced test theory for the bearing capacity test of foundation piles. To the additional settlement of the lower pile bottom brought on by the negative friction of the upper pile soil during the loading process in layered soils, the interaction effect between the upper piles and lower piles is first taken into account. To accurately convert the results of the self-balanced test pile into the traditional static load test curve form and solve the ultimate bearing capacity, the displacements and internal forces at micro-segment piles in each layer of soil were obtained using the finite difference method. Then, for verification, conventional static test piles and indoor model tests were conducted in a multi-layered ground foundation. The outcome demonstrates that the simplified conversion method’s bearing capacity of the test pile is greater than that of the traditional static pressure test, the analytical conversion method’s Q-s curve is relatively similar to the results of the conventional static load test, and the accuracy of the analytical conversion results is increased by about 9.3 percent. At the same time, the analytical conversion method was applied to the self-balanced test project of bored cast-in-place piles in Wutong Garden, Laibin, Guangxi, China, and the accurate bearing capacity and internal force deformation characteristics were obtained. The accuracy of the calculation result is improved by 12% compared with that of the simple conversion calculation result. Therefore, it can be widely promoted and applied in self-balanced pile bearing capacity test projects

Animal-Protein-Based and Synthetic-Based Foamed Mixture Lightweight Soil Doped with Bauxite Tailings: Macro and Microscopic Properties

In order to explore the effect of the foaming agent type on the properties of foamed mixture lightweight soil mixed with bauxite tailings (FMLSB), low-density (437.5 kg/m3 and 670 kg/m3) and high-density (902.5 kg/m3 and 1170 kg/m3) FMLSB were prepared using protein-based and synthetic-based foaming agents (AF and SF, respectively). The foam stability, micro characteristics, compressive strength, fluidity, and volume of water absorption of the FMLSB were investigated. The results showed that the foam made from AF had better strength and stability compared to SF. The internal pore sizes of both AF- and SF-FMLSB at low density were large, but at high density the internal pore sizes and area porosity of AF-FMLSB were smaller than those of SF-FMLSB. In terms of compressive strength, the compressive strength of AF-FMLSB was improved by 17.5% to 43.2% compared to SF-FMLSB. At low density, the fluidity of AF- and SF-FMLSB is similar, while at high density the fluidity of AF-FMLSB is much higher than that of SF-FMLSB. In addition, the stable volume of water absorption of SF-FMLSB is smaller than that of AF-FMLSB at low density, and the corresponding water resistance is better, but the situation is reversed at high density

Reduced connectivity in anterior cingulate cortex as an early predictor for treatment response in drug-naive, first-episode schizophrenia: A global-brain functional connectivity analysis

BACKGROUND: Antipsychotic medications may have acute effect on brain functional connectivity (FC) after only a few days of treatment. It is unclear if early changes in FC can predict treatment response in patients with schizophrenia. METHODS: The study included 32 patients with drug-naive, first-episode schizophrenia and 32 healthy controls. Resting-state functional magnetic resonance imaging was obtained from the patients at two time-points (pre-treatment baseline and 1week after treatment) and healthy controls at baseline. Patients were treated with olanzapine for 8weeks, and clinical symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) at three time points (baseline, 1week and 8weeks after treatment). Imaging data were analyzed using global-brain FC (GFC) and support vector regression (SVR). RESULTS: At baseline, an increased GFC was observed in bilateral anterior cingulate cortex (ACC) in patients compared with healthy controls. After 1week of olanzapine treatment, patients showed decreased GFC in bilateral ACC compared to the baseline values. SVR analysis suggested a positive relationship between GFC changes in bilateral ACC at week 1 and improvement in negative symptoms at week 8 (r=0.957, p \u3c 0.001). CONCLUSION: An early decrease in GFC in bilateral ACC may serve as a predictor for treatment response in patients with schizophrenia. If further confirmed, our finding may be able to help clinicians decide, during the early treatment course, whether the patient should stay on the chosen antipsychotic medication or switch to a different one