Effective removal of ammonia from aqueous solution through struvite synthesis and breakpoint chlorination: Insights into the synergistic effects of the hybrid system.

The ever-growing contamination of surface water due to various catchment activities poses threats and stress to downstream water treatment entities. Specifically, the presence of ammonia, microbial contaminants, organic matter, and heavy metals has been an issue of paramount concern to water treatment entities since stringent regulatory frameworks require these pollutants to be removed prior to water consumption. Herein, a hybrid approach that integrates struvite crystallization (precipitation) and breakpoint chlorination (stripping) for the removal of ammonia from aqueous solution was evaluated. To fulfil the goals of this study, batch experimental studies were pursued through the adoption of the well-known one-factor-at-a-time (AFAAT) method, specifically the effects of time, concentration/dosage, and mixing speed. The fate of chemical species was underpinned using the state-of-the-art analytical instruments and accredited standard methods. Cryptocrystalline magnesium oxide nanoparticles (MgO-NPs) were used as the magnesium source while the high-test hypochlorite (HTH) was used as the source of chlorine. From the experimental results, the optimum conditions were observed to be, i.e., Stage 1 - struvite synthesis, 110 mg/L of Mg and P dosage (concentration), 150 rpm of mixing speed, 60 min of contact time, and lastly, 120 min of sedimentation while optimum condition for the breakpoint chlorination (Stage 2) were 30 min of mixing and 8:1 Cl2:NH3 weight ratio. Specifically, in Stage 1, i.e., MgO-NPs, the pH increased from 6.7 to ≥9.6, while the turbidity was reduced from 9.1 to ≤1.3 NTU. Mn removal efficacy attained ≥97.70% (reduced from 174 µg/L to 4 µg/L) and Fe attained ≥96.64% (reduced from 11 mg/L to 0.37 mg/L). Elevated pH also led to the deactivation of bacteria. In Stage 2, i.e. breakpoint chlorination, the product water was further polished by eliminating residual ammonia and TPC at 8:1 Cl2-NH3 weight ratio. Interestingly, ammonia was reduced from 6.51 to 2.1 mg/L in Stage 1 (67.74% removal) and then from 2.1 to 0.002 mg/L post breakpoint chlorination (99.96% removal), i.e., stage 2. Overall, synergistic and complementary effects of integrating struvite synthesis and breakpoint chlorination hold great promise for the removal of ammonia from aqueous solutions thus confirming that this technology could potentially be used to curtail the effects of ammonia in the receiving environments and drinking water.

Static and treatment-responsive brain biomarkers of depression relapse vulnerability following prophylactic psychotherapy: Evidence from a randomized control trial.

BACKGROUND: Neural reactivity to dysphoric mood induction indexes the tendency for distress to promote cognitive reactivity and sensory avoidance. Linking these responses to illness prognosis following recovery from Major Depressive Disorder informs our understanding of depression vulnerability and provides engagement targets for prophylactic interventions. METHODS: A prospective fMRI neuroimaging design investigated the relationship between dysphoric reactivity and relapse following prophylactic intervention. Remitted depressed outpatients (N = 85) were randomized to 8 weeks of Cognitive Therapy with a Well-Being focus or Mindfulness Based Cognitive Therapy. Participants were assessed before and after therapy and followed for 2 years to assess relapse status. Neural reactivity common to both assessment points identified static biomarkers of relapse, whereas reactivity change identified dynamic biomarkers. RESULTS: Dysphoric mood induction evoked prefrontal activation and sensory deactivation. Controlling for past episodes, concurrent symptoms and medication status, somatosensory deactivation was associated with depression recurrence in a static pattern that was unaffected by prophylactic treatment, HR 0.04, 95% CI [0.01, 0.14], p < .001. Treatment-related prophylaxis was linked to reduced activation of the left lateral prefrontal cortex (LPFC), HR 3.73, 95% CI [1.33, 10.46], p = .013. Contralaterally, the right LPFC showed dysphoria-evoked inhibitory connectivity with the right somatosensory biomarker CONCLUSIONS: These findings support a two-factor model of depression relapse vulnerability, in which: enduring patterns of dysphoria-evoked sensory deactivation contribute to episode return, but vulnerability may be mitigated by targeting prefrontal regions responsive to clinical intervention. Emotion regulation during illness remission may be enhanced by reducing prefrontal cognitive processes in favor of sensory representation and integration.

Conversion of a low value industrial waste into biodiesel using a catalyst derived from brewery waste: An activation and deactivation kinetic study.

In this study, biodiesel was produced by using a heterogeneous acid catalyst made from brewer's spent yeast (BSY). BSY was initially activated by phosphoric acid followed by carbonization in inert atmosphere and sulfonation process to prepare the catalyst. It is completely characterized using sophisticated instruments to determine its physical and chemical properties. Subsequently, the effectiveness of the catalyst was analyzed by subjecting it to sonochemical esterification of an industrial low value waste product, palm fatty acid distillate (PFAD). The reactions were performed in the presence of ultrasound at a constant frequency of 25 kHz. An optimum methyl ester conversion of 87.8% was achieved at 8 wt% of catalyst, 21:1 methanol to PFAD molar ratio, 65 °C and 180 min of reaction time. The catalyst displayed a high catalytic stability up to four cycles due to firm SO3H functional group attached onto the surface. Furthermore, a novel sonochemical kinetic model was proposed for surface esterification reaction on the catalyst. The reaction rate was found and it followed a pseudo-first-order reaction mechanism. Furthermore, a deactivation model was also proposed to account for the loss of activity upon catalyst reuse during sonochemical reaction.

Data-driven tensor independent component analysis for model-based connectivity neurofeedback.

Neurofeedback based on real-time functional MRI is an emerging technique to train voluntary control over brain activity in healthy and disease states. Recent developments even allow for training of brain networks using connectivity feedback based on dynamic causal modeling (DCM). DCM is an influential hypothesis-driven approach that requires prior knowledge about the target brain network dynamics and the modulatory influences. Data-driven approaches, such as tensor independent component analysis (ICA), can reveal spatiotemporal patterns of brain activity without prior assumptions. Tensor ICA allows flexible data decomposition and extraction of components consisting of spatial maps, time-series, and session/subject-specific weights, which can be used to characterize individual neurofeedback regulation per regulation trial, run, or session. In this study, we aimed to better understand the spatiotemporal brain patterns involved and affected by model-based feedback regulation using data-driven tensor ICA. We found that task-specific spatiotemporal brain patterns obtained using tensor ICA were highly consistent with model-based feedback estimates. However, we found that the DCM approach captured specific network interdependencies that went beyond what could be detected with either general linear model (GLM) or ICA approaches. We also found that neurofeedback-guided regulation resulted in activity changes that were characteristic of the mental strategies used to control the feedback signal, and that these activity changes were not limited to periods of active self-regulation, but were also evident in distinct gradual recovery processes during subsequent rest periods. Complementary data-driven and model-based approaches could aid in interpretation of the neurofeedback data when applied post-hoc, and in the definition of the target brain area/pattern/network/model prior to the neurofeedback training study when applied to the pilot data. Systematically investigating the triad of mental effort, spatiotemporal brain network changes, and activity and recovery processes might lead to a better understanding of how learning with neurofeedback is accomplished, and how such learning can cause plastic brain changes along with specific behavioral effects.

Deactivation of E. coli in water using Fe3+-saturated montmorillonite impregnated filter paper.

In areas with high exposure to pathogen contaminated water and lack the economic means for water treatment, low cost and convenient point-of-use drinking water disinfection materials/devices are essential. Using a simple craft paper making method, Fe3+-saturated montmorillonite impregnated filter paper was constructed to filter live Escherichia coli (E. coli)-spiked water. The Scanning Electron Microscopic images of the E. coli cells in contact with the Fe3+-saturated montmorillonite impregnated filter paper showed: 1) Fe3+-saturated montmorillonite particles were uniformly coated on the cellulose paper fiber, creating large mineral surface for cell contact; and 2) E. coli cell membrane was dehydrated and damaged, resulting cell deactivation upon contacting with the Fe3+-saturated montmorillonite particles impregnated in the paper. The E. coli cells passing through the Fe3+-saturated montmorillonite impregnated filter paper were not viable as further confirmed by the microfluidic dielectrophoresis analysis. They remained non-viable at room temperature even after 5 days, as shown by the results from both the Colony Counting test and the Colilert test. More than 99.5% deactivation efficiency was achieved when the ratio of the volume of the E. coli contaminated water to the mass of Fe3+-saturated montmorillonite was maintained at <1:1.5 (mL/mg). The Fe3+-saturated montmorillonite impregnated filter paper maintained ~74% E. coli deactivation efficiency even after the 8th consecutive use. About 0.52 mg Fe3+, which is bioavailable, could be leached into the water for every 2 L E coli-contaminated water that is treated with the filter paper. The treated water could therefore provide iron supplement to a person at a level within the range of the FDA recommended human daily intake of iron. The results from this study has clearly demonstrated promising potential of using the Fe3+-saturated montmorillonite impregnated filter paper for low cost (~$0.07/L treated water for this study) and convenient point-of-use drinking water disinfection.

The Effects of Bushen Capsule on Episodic Memory in Amnestic Mild Cognitive Impairment Patients: A Pilot Placebo Controlled fMRI Study.

BACKGROUND: Observing the effects of a drug on episodic memory and the underlying brain function has extreme significance in evaluating its therapeutic value in treating amnestic mild cognitive impairment (aMCI). OBJECTIVE: To observe the effects of Bushen capsule (BSC), a Chinese herbal medicine, on episodic memory in aMCI and further explore the underlying mechanism. METHODS: 44 aMCI patients from hospitals and local communities in Beijing were randomly divided into the BSC treatment group (22 patients orally treated with BSC) and the placebo group (22 patients treated with placebo). The duration of intervention lasted for 3 months. Before and after the 3 months treatment, neuropsychological tests and fMRI examinations were carried out to assess cognitive ability and brain activation changes, respectively. RESULTS: Compared to the placebo group, the BSC group presented a significant increase in the AVLT(N5) (p = 0.003) and Stroop (C-B) time (p = 0.002). fMRI results showed a reduction of brain negative activation in the right middle temporal gyrus and a positive activation enhancement in the right putamen among the BSC group after treatment. Meanwhile, the variation in activation values in the right middle temporal gyrus was significantly correlated with the improvement in test values of AVLT(N5), and the variation in deactivation values in the right putamen was significantly correlated with the improvement in test values of Stroop (C-B) time. CONCLUSIONS: BSC can improve the behavioral performances of episodic memory in aMCI; this effect may be related to its modulation on the activations of the temporal lobe and the putamen under episodic memory encoding task.

Cortical network switching: possible role of the lateral septum and cholinergic arousal.

BACKGROUND: Cortical networks undergo large-scale switching between states of increased or decreased activity in normal sleep and cognition as well as in pathological conditions such as epilepsy. We previously found that focal hippocampal seizures in rats induce increased neuronal firing and cerebral blood flow in subcortical structures including the lateral septal area, along with frontal cortical slow oscillations resembling slow wave sleep. In addition, stimulation of the lateral septum in the absence of a seizure resulted in cortical deactivation with slow oscillations. HYPOTHESIS: We hypothesized that lateral septal activation might cause neocortical deactivation indirectly, possibly through impaired subcortical arousal. But how does subcortical stimulation cause slow wave activity in frontal cortex? How do arousal neurotransmitter levels (e.g. acetylcholine) change in cortex during the excitation of inhibitory projection nuclei? METHODS AND RESULTS: In the current study, we used simultaneous electrophysiology and enzyme-based amperometry in a rat model, and found a decrease in choline, along with slow wave activity in orbital frontal cortex during lateral septal stimulation in the absence of seizures. In contrast, the choline signal and local field potential in frontal cortex had no significant changes when stimulating the hippocampus, but showed increased choline and decreased slow wave activity with an arousal stimulus produced by toe pinch. CONCLUSIONS: These findings indicate that the activation of subcortical inhibitory structures (such as lateral septum) can depress subcortical cholinergic arousal. This mechanism may play an important role in large-scale transitions of cortical activity in focal seizures, as well as in normal cortical function.

Modality effects in paced serial addition task: differential responses to auditory and visual stimuli.

Paced Auditory Serial-Addition Task (PASAT) is a complex task commonly used to examine patients with diffuse brain damage. A visual version of the neuropsychological test (Paced Visual Serial-Addition Task, PVSAT) has also been introduced to clinical practice, and both versions were adapted to be used in neuroimaging, namely functional magnetic resonance imaging (fMRI). The aim of our work was direct comparison of auditory and visual versions of the paced serial addition test (PASAT/PVSAT) in a within-subject and within-session study and description of the commonalities and differences in both activated and deactivated brain regions. Twenty young adult right-handed healthy volunteers participated in the study and underwent whole-brain fMRI examination during PASAT and PVSAT performance. Higher-level statistical analysis was performed to generate group mean activation and deactivation maps for both tasks, their conjunctions and differences across modalities. In PASAT/PVSAT activation conjunction analysis, we confirmed the existence of a modality-independent neural network similar to working memory tasks and to previous PASAT or PVSAT studies. In PASAT/PVSAT deactivation conjunction analysis, we observed a rather symmetrical extensive pattern of deactivated regions, overlapping the default mode network. Significant differences between PASAT and PVSAT were found in the right frontal eye field (FEF) and bilaterally in the striate and extrastriate cortices. Activation in one task and deactivation in the other jointly contributed to significant differences in all occipital and occipitotemporal regions. Both tasks activated right FEF, but activation during PASAT was significantly stronger than during PVSAT. Between-modality differences should be considered when preparing and interpreting neuroimaging experiments.

Structural network underlying visuospatial imagery in humans.

INTRODUCTION: Several neuroimaging studies have shown that visuospatial imagery is associated with a multitude of activation nodes spanning occipital, parietal, temporal and frontal brain areas. However, the anatomical connectivity profile linking these areas is not well understood. Specifically, it is unknown whether cortical areas activated during visuospatial imagery are directly connected to one another, or whether few act as hubs which facilitate indirect connections between distant sites. Addressing this is important since mental imagery tasks are commonly used in clinical settings to assess complex cognitive functions such as spatial orientation. METHODS: We recorded functional magnetic resonance imaging (fMRI) data while participants (N = 18) performed a visuospatial imagery task. In the same subjects, we acquired diffusion MRI (dMRI) and used state-of-the-art tractography robust to fiber crossings to reconstruct the white matter tracts linking the fMRI activation sites. For each pair of these sites, we then computed the fraction of subjects showing a connection between them. RESULTS: Robust fMRI activation was observed in cortical areas spanning the dorsal (extrastriate, parietal and prefrontal areas) and ventral (temporal and lingual areas) pathways, as well as moderate deactivation in striate visual cortex. In over 80% of subjects, striate cortex showed anatomical connectivity with extrastriate (medial occipital) and lingual (posterior cingulate cortex-PCC) sites with the latter showing divergent connections to ventral (parahippocampus) and dorsal (BA7) activation areas. CONCLUSION: Our results demonstrate that posterior cingulate cortex is not only activated by visuospatial imagery, but also serves as an anatomical hub linking activity in occipital, parietal and temporal areas. This finding adds to the growing body of evidence pointing to PCC as a connector hub which may facilitate integration across widespread cortical areas.

Selective catalytic oxidation of H2S over iron oxide supported on alumina-intercalated Laponite clay catalysts.

A series of iron oxide supported on alumina-intercalated clay catalysts (named Fe/Al-Lap catalysts) with mesoporous structure and high specific surface area were prepared. The structural and chemical properties were studied by nitrogen sorption isotherms, X-ray diffraction (XRD), UV-vis diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectra (XPS), Fourier transform infrared spectroscopy (FTIR), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD) techniques. It was realized that iron oxide mainly existed in the form of isolated Fe(3+) in an oxidic environment. Fe/Al-Lap catalysts showed high catalytic activities in the temperature range of 120-200 °C without the presence of excessive O2. This can be attributed to the interaction between iron oxide and alumina, which improve the redox property of Fe(3+) efficiently. In addition, the strong acidity of catalysts and good dispersion of iron oxide were also beneficial to oxidation reaction. Among them, 7% Fe/Al-Lap catalyst presented the best catalytic performance at 180 °C. Finally, the catalytic and deactivation mechanisms were explored.