Online and offline effects of parietal 10 Hz repetitive transcranial magnetic stimulation on working memory in healthy controls.

Parietal alpha activity shows a specific pattern of phasic changes during working memory. It decreases during the encoding and recall phases but increases during the maintenance phase. This study tested whether online rTMS delivered to the parietal cortex during the maintenance phase of a working memory task would increase alpha activity and hence improve working memory. Then, 46 healthy volunteers were randomly assigned to two groups to receive 3-day parietal 10 Hz online rTMS (either real or sham, 3600 pulses in total) that were time-locked to the maintenance phase of a spatial span task (180 trials in total). Behavioral performance on another spatial span task and EEG signals during a change detection task were recorded on the day before the first rTMS (pretest) and the day after the last rTMS (posttest). We found that rTMS improved performance on both online and offline spatial span tasks. For the offline change detection task, rTMS enhanced alpha activity within the maintenance phase and improved interference control of working memory at both behavioral (K score) and neural (contralateral delay activity) levels. These results suggested that rTMS with alpha frequency time-locked to the maintenance phase is a promising way to boost working memory.

Toxic element characterization against a typical high geology background: Pollution enrichment, source tracking, spatial distribution, and ecological risk assessment.

The geological environment determines the initial content of various elements in soil, while the late input of toxic elements produced through weathering and leaching is a persistent threat to food security and human health. In this study, we selected the Lou Shao Basin, a black rock system background, and combined geostatistical analysis and multivariate statistics to quantify the specific contribution of weathering of the black rock system, and to analyze the source traces, spatial distributions, and ecological risks of the soil toxicity of elements. The results show that the soils in the study area are acidic, which is related to the weathering of sulfides in the black rock system. The concentrations of most elements in the soil were determined to exceed the soil background values, and the Cd, Se and N contents, exceeded more than five times, especially Se, Mo nearly as high as 13 times. Strong positive correlation between Se, Cu, V and P, low correlation between N and Se, Cu, V, P, Ni and Cd.72.52%, 43%, 77.79%, 82%, 77%, and 44.1% of Cd, Se, Ni, Cu, B, and Mo came from the black rock system, respectively, which were greatly affected by geogenic weathering; V, Zn, Pb, and As are mainly from biomass burning sources; N and P are mainly from agricultural surface sources. Comparison found that the Cd and Se elements in the rocks in the study area were 16.78 times and 1.36 times higher than the world shale average, respectively, and need to pay attention to the weathering process of the two, and the spatial distribution of the 12 elements in soils showed a striped and centralized block distribution pattern, specifically around the distribution of carbonate and metamorphic rocks and other high-geology blocks. The ecological risk results showed that Cd was the main element causing high ecological risk, followed by Se and N, which were at moderate to high ecological risk levels, and Se and N showed similar ecological risk patterns, which may be related to the fact that selenium can promote the uptake and transformation of nitrogen. The present results add to the endogenous sources of toxic elements, quantify the source contributions of toxic elements in soils with high geologic backgrounds, fill this knowledge gap, and provide new insights for pollution control and ecological protection in areas with high geochemical backgrounds.

Low-frequency rTMS targeting individual self-initiated finger-tapping task activation modulates the amplitude of local neural activity in the putamen.

Repetitive transcranial magnetic stimulation (rTMS) has been used in the clinical treatment of Parkinson's disease (PD). Most of rTMS studies on PD used high-frequency stimulation; however, excessive nonvoluntary movement may represent abnormally cortical excitability, which is likely to be suppressed by low-frequency rTMS. Decreased neural activity in the basal ganglia on functional magnetic resonance imaging (fMRI) is a characteristic of PD. In the present study, we found that low-frequency (1 Hz) rTMS targeting individual finger-tapping activation elevated the amplitude of local neural activity (percentage amplitude fluctuation, PerAF) in the putamen as well as the functional connectivity (FC) of the stimulation target and basal ganglia in healthy participants. These results provide evidence for our hypothesis that low-frequency rTMS over the individual task activation site can modulate deep brain functions, and that FC might serve as a bridge transmitting the impact of rTMS to the deep brain regions. It suggested that a precisely localized individual task activation site can act as a target for low-frequency rTMS when it is used as a therapeutic tool for PD.

Resting-State fMRI Functional Connectivity Strength Predicts Local Activity Change in the Dorsal Cingulate Cortex: A Multi-Target Focused rTMS Study.

Previous resting state functional magnetic resonance imaging (RS-fMRI) studies suggested that repetitive transcranial magnetic stimulation (rTMS) can modulate local activity in distant areas via functional connectivity (FC). A brain region has more than one connection with the superficial cortical areas. The current study proposed a multi-target focused rTMS protocol for indirectly stimulating a deep region, and to investigate 1) whether FC strength between stimulation targets (right middle frontal gyrus [rMFG] and right inferior parietal lobule [rIPL]) and effective region (dorsal anterior cingulate cortex [dACC]) can predict local activity changes of dACC and 2) whether multiple stimulation targets can focus on the dACC via FC. A total of 24 healthy participants received rTMS with two stimulation targets, both showing strong FC with the dACC. There were four rTMS conditions (>1 week apart, 10 Hz, 1800 pulses for each): rMFG-target, rIPL-target, Double-targets (900 pulses for each target), and Sham. The results failed to validate the multi-target focused rTMS hypothesis. But rMFG-target significantly decreased the local activity in the dACC. In addition, stronger dACC-rMFG FC was associated with a greater local activity change in the dACC. Future studies should use stronger FC to focus stimulation effects on the deep region.

Intermittent theta burst stimulation over the parietal cortex has a significant neural effect on working memory.

The crucial role of the parietal cortex in working memory (WM) storage has been identified by fMRI studies. However, it remains unknown whether repeated parietal intermittent theta-burst stimulation (iTBS) can improve WM. In this within-subject randomized controlled study, under the guidance of fMRI-identified parietal activation in the left hemisphere, 22 healthy adults received real and sham iTBS sessions (five consecutive days, 600 pulses per day for each session) with an interval of 9 months between the two sessions. Electroencephalography signals of each subject before and after both iTBS sessions were collected during a change detection task. Changes in contralateral delay activity (CDA) and K-score were then calculated to reflect neural and behavioral WM improvement. Repeated-measures ANOVA suggested that real iTBS increased CDA more than the sham one (p = .011 for iTBS effect). Further analysis showed that this effect was more significant in the left hemisphere than in the right hemisphere (p = .029 for the hemisphere-by-iTBS interaction effect). Pearson correlation analyses showed significant correlations for two conditions between CDA changes in the left hemisphere and K score changes (ps <.05). In terms of the behavioral results, significant K score changes after real iTBS were observed for two conditions, but a repeated-measures ANOVA showed a nonsignificant main effect of iTBS (p = .826). These results indicate that the current iTBS protocol is a promising way to improve WM capability based on the neural indicator (CDA) but further optimization is needed to produce a behavioral effect.

Finger Tapping Task Activation vs. TMS Hotspot: Different Locations and Networks.

Both functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) have been used to non-invasively localize the human motor functional area. These locations can be clinically used as stimulation target of TMS treatment. However, it has been reported that the finger tapping fMRI activation and TMS hotspot were not well-overlapped. The aim of the current study was to measure the distance between the finger tapping fMRI activation and the TMS hotspot, and more importantly, to compare the network difference by using resting-state fMRI. Thirty healthy participants underwent resting-state fMRI, task fMRI, and then TMS hotspot localization. We found significant difference of locations between finger tapping fMRI activation and TMS hotspot. Specifically, the finger tapping fMRI activation was more lateral than the TMS hotspot in the premotor area. The fMRI activation peak and TMS hotspot were taken as seeds for resting-state functional connectivity analyses. Compared with TMS hotspot, finger tapping fMRI activation peak showed more intensive functional connectivity with, e.g., the bilateral premotor, insula, putamen, and right globus pallidus. The findings more intensive networks of finger tapping activation than TMS hotspot suggest that TMS treatment targeting on the fMRI activation area might result in more remote effects and would be more helpful for TMS treatment on movement disorders.

High-Resolution U-Net: Preserving Image Details for Cultivated Land Extraction.

Accurate and efficient extraction of cultivated land data is of great significance for agricultural resource monitoring and national food security. Deep-learning-based classification of remote-sensing images overcomes the two difficulties of traditional learning methods (e.g., support vector machine (SVM), K-nearest neighbors (KNN), and random forest (RF)) when extracting the cultivated land: (1) the limited performance when extracting the same land-cover type with the high intra-class spectral variation, such as cultivated land with both vegetation and non-vegetation cover, and (2) the limited generalization ability for handling a large dataset to apply the model to different locations. However, the "pooling" process in most deep convolutional networks, which attempts to enlarge the sensing field of the kernel by involving the upscale process, leads to significant detail loss in the output, including the edges, gradients, and image texture details. To solve this problem, in this study we proposed a new end-to-end extraction algorithm, a high-resolution U-Net (HRU-Net), to preserve the image details by improving the skip connection structure and the loss function of the original U-Net. The proposed HRU-Net was tested in Xinjiang Province, China to extract the cultivated land from Landsat Thematic Mapper (TM) images. The result showed that the HRU-Net achieved better performance (Acc: 92.81%; kappa: 0.81; F1-score: 0.90) than the U-Net++ (Acc: 91.74%; kappa: 0.79; F1-score: 0.89), the original U-Net (Acc: 89.83%; kappa: 0.74; F1-score: 0.86), and the Random Forest model (Acc: 76.13%; kappa: 0.48; F1-score: 0.69). The robustness of the proposed model for the intra-class spectral variation and the accuracy of the edge details were also compared, and this showed that the HRU-Net obtained more accurate edge details and had less influence from the intra-class spectral variation. The model proposed in this study can be further applied to other land cover types that have more spectral diversity and require more details of extraction.

A preliminary study of multispectral Cherenkov imaging and a Fricke-xylenol orange gel film (MCIFF) for online, absolute dose measurement.

BACKGROUND: Cherenkov luminescence imaging has shown potential for relative dose distribution and field verification in radiation therapy. However, to date, limited research utilizing Cherenkov luminescence for absolute dose calibration has been conducted owing to uncertainties arising from camera positioning and tissue surface optical properties. PURPOSE: This paper introduces a novel approach to multispectral Cherenkov luminescence imaging combined with Fricke-xylenol orange gel (FXG) film, termed MCIFF, which can enable online full-field absolute dose measurement. By integrating these two approaches, MCIFF allows for calibration of the ratio between two spectral intensities with absorbed dose, thereby enabling absolute dose measurement. METHODS: All experiments are conducted on a Varian Clinac 23EX, utilizing an electron multiplying charge-coupled device (EMCCD) camera and a two-way image splitter for simultaneous capture of two-spectral Cherenkov imaging. In the first part of this study, the absorbance curves of the prepared FXG film, which receives different doses, are measured using a fluorescence spectrophotometer to verify the correlation between absorbance and dose. In the second part, the FXG film is positioned directly under the radiation beam to corroborate the dose measurement capacity of MCIFF across various beams. In the third part, the feasibility of MCIFF is tested in actual radiotherapy settings via a humanoid model, demonstrating its versatility with various radiotherapy materials. RESULTS: The results of this study indicate that the logarithmic ratios of spectral intensities at wavelengths of 550 ± 50 and 700 ± 100 nm accurately reflect variations in radiation dose (R2 > 0.96) across different radiation beams, particle energies, and dose rates. The slopes of the fitting lines remain consistent under varying beam conditions, with discrepancies of less than 8%. The optical profiles obtained using the MCIFF exhibit a satisfactory level of agreement with the measured results derived from the treatment planning system (TPS) and EBT3 films. Specifically, for photon beams, the lateral distances between the 80% and 20% isodose lines, referred to as the penumbra (P80-20) values, obtained through TPS, EBT3 films, and MCIFF, are determined as 0.537, 0.664, and 0.848 cm, respectively. Similarly, for electron beams, the P80-20 values obtained through TPS, EBT3 films, and MCIFF are found to be 0.432, 0.561, and 0.634 cm, respectively. Furthermore, imaging of the anthropomorphic phantom demonstrates the practical application of MCIFF in real radiotherapy environments. CONCLUSION: By combining an FXG film with Cherenkov luminescence imaging, MCIFF can calibrate Cherenkov luminescence to absorbed dose, filling the gap in online 2D absolute dose measurement methods in clinical practice, and providing a new direction for the clinical application of optical imaging to radiation therapy.

Black shale high geological background potential toxic elements(PTEs) in middle reaches of the Yangtze River tributary basin water environment, China: Distribution, pollution sources, and risk assessment.

As a typical high geological background area in the middle reaches of the Yangtze River tributary basin in China, the Loushao Basin in Hunan is covered with high mineral black shale, with an average element value 4.76-8.97 times higher than the world average rock level. The aim of this study is to analyze the water environment pollution in the middle reaches of the Yangtze River tributary basin under high geological background based on the spatial distribution differences of black shale concentration. PCA source analysis is used to track the source of pollution and highlight the differences in body shape to assess regional health risks. The research results show that Cd in water quality exceeds the background value by 7.5 times. There is a strong homology among Pb, Cd, Cr, As, and Hg elements in water bodies, mainly derived from the natural weathering, migration, and enrichment of rocks. Hg element is a pollution caused by human factors, and water pollution is more severe in areas close to high concentrations, with severe exceedance of Cr element in water quality. The main controlling factor for individual health risk differences is body shape, and men's health is more susceptible to threats.

Potential toxic heavy metals in village rainwater runoff of antimony mining area, China: Distribution, pollution sources, and risk assessment.

The potential toxic heavy metal runoff from antimony mining areas poses a serious threat to the water environment and the health of residents in the village. The study found that the average concentrations of As, Sb, Cr, Pb, and Cd in the runoff were 0.1237, 0.1148, 0.0332, 0.0140, and 0.0013 mg/L, which were higher than the normal average concentrations in the water environment of 0.018, 0.0009, 0.05, 0.012, and 0.000013 mg/L, respectively.Sb and As are severely polluted, while Cd, Pb, and Cr have lower pollution levels. The coefficients of variation for As, Sb, Cr, Pb, and Cd range from 0.079 to 1.051, with Sb showing exceptionally high variability. Heavy metal elements Pb, Cd, and Sb accumulate in the southeastern area of the village, with Sb concentrations decreasing from the southeast to the northwest. As is mainly distributed in the northeastern part of the village, while Cr is primarily found in the central-western region. Source analysis indicates that As and Sb originate from mining and industrial activities, dust deposition, and domestic sewage. Cr comes from the natural geological background and metal product industry, Pb from lead-acid batteries, industrial activities, and gasoline additives, and Cd from fertilization in residential green areas and pesticide use. Health risk analysis reveals that the hazard index (HI) values for As and As in the water environment are 1.49 and 2.31, respectively, both exceeding 1, posing a serious threat to the health of village residents. The HI values for Pb, Cr, and Cd elements are all below 1, indicating lower risks. This study identified that Sb in the antimony ore area and its associated metal element As are the main elements leading to potential heavy metal pollution in the runoff of village residential areas, providing direction for subsequent water environment restoration work.

Adsorption of Sb(III) and Pb(II) in wastewater by magnetic γ-Fe2O3-loaded sludge biochar: Performance and mechanisms.

Magnetically modified carbon-based adsorbent (BC@γ-Fe2O3) was prepared through facile route using activated sludge biomass and evaluated for the simultaneous removal of Sb(III) and Pb(II). BC@γ-Fe2O3 exhibited outstanding Sb(III) and Pb(II) adsorption capacity when 200 mg of adsorbent was employed at pH 5.0 for 240 min, with the removal efficiency higher than 90%. The experiments demonstrated the excellent reusability and the potent anti-interference properties of the prepared absorbent. Freundlich and pseudo-second-order kinetic were prior to describe the adsorption process. The adsorption of Sb(III) and Pb(II) onto BC@γ-Fe2O3 was spontaneous and endothermic. BC@γ-Fe2O3 with high specific surface area revealed the exceptional competence to absorb Sb(III) and Pb(II) through pore filling, electrostatic adsorption and complexation. The adsorption mechanisms of Sb(III) and Pb(II) showed similarities with slight disparities. The removal of Sb(III) involved the Fe-O-Sb bond and π-π bond, while the adsorption of Pb(II) was closely related to ion exchange. Moreover, Sb(III) was oxidized to Sb(V) in a minor part during adsorption. The Fe-O-Cl active sites on BC allowed for the binding of γ-Fe2O3, guaranteeing the abundant adsorption sites and stability. BC@γ-Fe2O3 provides an efficient and green insight into the simultaneous removal of complex heavy metals with promising application in wastewater treatment.

Black shale bedrock control of soil heavy metal typical high geological background in China Loushao Basin: Pollution characteristics, source and Influence assessment based on spatial analysis.

During the process of black shale weathering, multiple heavy metal elements are concentrated in the soil, causing pollution. This study selected soil and black shale bedrock samples from high geological background areas to investigate the control of heavy metal element pollution by bedrock using spatial analysis. The research results indicate that the heavy metal content in black shale bedrock is extremely high, ranging from 2.3 to 13.1 times the background values of rock heavy metal elements. The heavy metal content in the soil formed through weathering is positively correlated with the bedrock, ranging from 1.1 to 21.3 times the background values. The coefficient of variation of rock samples ranges from 1.09 to 7.18, indicating significant variability.The analysis reveals that the control ability of pure rock over heavy metal elements is mainly moderate and high, accounting for over 70 %, with d being the most affected metal element. Except for As, the other seven elements exhibit strong spatial autocorrelation, showing distinct regional distribution characteristics. The soil elements demonstrate high homogeneity, with heavy metal elements from black shale bedrock primarily released through weathering serving as the main source of these elements.

Psychometric Properties and Measurement Invariance Across Sex of the Wong and Law Emotional Intelligence Scale in Chinese adolescents.

The aim of this study was to validate the Wong and Law Emotional Intelligence Scale (WLEIS) in Chinese adolescents by examining factor structure, sex-related measurement invariance and latent mean differences, reliability, and criterion-related validity.A total of 1674 Chinese adolescents aged 12-17 years old (Mage = 15.26, SD = .58) were recruited. Results of confirmatory factor analysis (CFA) supported the four-factor model of the WLEIS as the best fit to the data. Multi-group CFA suggested that the measurement structure of the WLEIS was invariant across sex. Testing for the latent mean differences showed that male adolescents scored lower on the Other-Emotional Appraisal subscale, but scored higher on the Regulation of Emotion subscale than female adolescents. Furthermore, all the subscales of male and female adolescents had satisfactory composite reliability. Finally, the WLEIS had favorable criterion-related validity with self-esteem, life satisfaction, positive affect, negative affect and perceived stress. These findings suggested that the WLEIS is a reliable and valid instrument for assessing trait emotional intelligence of adolescents and can be generalized across sex.

An artificial remote tactile device with 3D depth-of-field sensation.

Flexible tactile neuromorphic devices are becoming important as the impetus for the development of human-machine collaboration. However, accomplishing and further transcending human intelligence with artificial intelligence still confront many barriers. Here, we present a self-powered stretchable three-dimensional remote tactile device (3D-RTD) that performs the depth-of-field (DOF) sensation of external mechanical motions through a conductive-dielectric heterogeneous structure. The device can build a logic relationship precisely between DOF motions of an external active object and sensory potential signals of bipolar sign, frequency, amplitude, etc. The sensory mechanism is revealed on the basis of the electrostatic theory and multiphysics modeling, and the performance is verified via an artificial-biological hybrid system with micro/macroscale interaction. The feasibility of the 3D-RTD as an obstacle-avoidance patch for the blind is systematically demonstrated with a rat. This work paves the way for multimodal neuromorphic device that transcends the function of a biological one toward a new modality for brain-like intelligence.

Pregenual or subgenual anterior cingulate cortex as potential effective region for brain stimulation of depression.

BACKGROUND: The dorsolateral prefrontal cortex (DLPFC) is the standard stimulation target for the repetitive transcranial magnetic stimulation (rTMS) treatment of major depression disorder (MDD). A retrospective study by Fox and colleagues found that a more negative resting-state functional magnetic resonance imaging (RS-fMRI) functional connectivity (FC) between left DLPFC and the subgenual anterior cingulate cortex (sgACC) in a large group of healthy participants is associated with a better curative effects of rTMS in MDD, suggesting that the sgACC may be an effective region. However, a recent meta-analysis on RS-fMRI studies found that the pregenual ACC (pgACC), rather than the sgACC, of MDD patients showed increased local activity. METHODS: We used the stimulation coordinates in the left DLPFC analyzed by Fox et al. to perform RS-fMRI FC between the stimulation targets obtained from previous rTMS MDD studies and the potential effective regions (sgACC and pgACC, respectively) on the RS-fMRI data from 88 heathy participants. RESULTS: (a) Both the pgACC and the sgACC were negatively connected to the left DLPFC; (b) both FCs of sgACC-DLPFC and pgACC-DLPFC were more negative in responders than in nonresponders; and (c) the associations between DLPFC-sgACC functional connectivity and clinical efficacy were clustered around the midline sgACC. CONCLUSIONS: Both the pgACC and the sgACC may be potential effective regions for rTMS on the left DLPFC for treatment of MDD. However, individualized ACC-DLPFC FC-based rTMS on depression should be performed in the future to test the pgACC or the sgACC as effective regions.

High-Frequency rTMS of the Motor Cortex Modulates Cerebellar and Widespread Activity as Revealed by SVM.

Functional magnetic resonance imaging (fMRI) studies have shown that the effect of repetitive transcranial magnetic stimulation (rTMS) can induce changes in remote brain regions. In the stimulated regions, low-frequency (≤1 Hz) rTMS induces inhibitory effects, while high-frequency (≥5 Hz) stimulation induces excitatory effects. However, these stereotypical effects arising from low- and high-frequency stimulation are based on measurements of motor evoked potentials (MEPs) induced by pulsed stimulation. To test the effects of rTMS on remote brain regions, the current study recruited 31 young healthy adults who participated in three rTMS sessions (10 Hz high frequency, 1 Hz low frequency, and sham) on three separate days. The stimulation target was based on individual fMRI activation in the motor cortex evoked by a finger movement task. Pre- and post-rTMS resting-state fMRI (RS-fMRI) were acquired. Regional homogeneity (ReHo) and degree centrality (DC) were calculated to measure the local and global connectivity, respectively. Compared with the sham session, high-frequency (10 Hz) rTMS significantly increased ReHo and DC in the right cerebellum, while low-frequency (1 Hz) stimulation did not significantly alter ReHo or DC. Then, using a newly developed PAIR support vector machine (SVM) method, we achieved accuracy of 93.18-97.24% by split-half validation for pairwise comparisons between conditions for ReHo or DC. While the univariate analyses suggest that high-frequency rTMS of the left motor cortex could affect distant brain activity in the right cerebellum, the multivariate SVM results suggest that both high- and low-frequency rTMS significantly modulated widespread brain activity. The current findings are useful for increasing the understanding of the mechanisms of rTMS, as well as guiding precise individualized rTMS treatment of movement disorders.

Intra- and Inter-Scanner Reliability of Voxel-Wise Whole-Brain Analytic Metrics for Resting State fMRI.

As the multi-center studies with resting-state functional magnetic resonance imaging (RS-fMRI) have been more and more applied to neuropsychiatric studies, both intra- and inter-scanner reliability of RS-fMRI are becoming increasingly important. The amplitude of low frequency fluctuation (ALFF), regional homogeneity (ReHo), and degree centrality (DC) are 3 main RS-fMRI metrics in a way of voxel-wise whole-brain (VWWB) analysis. Although the intra-scanner reliability (i.e., test-retest reliability) of these metrics has been widely investigated, few studies has investigated their inter-scanner reliability. In the current study, 21 healthy young subjects were enrolled and scanned with blood oxygenation level dependent (BOLD) RS-fMRI in 3 visits (V1 - V3), with V1 and V2 scanned on a GE MR750 scanner and V3 on a Siemens Prisma. RS-fMRI data were collected under two conditions, eyes open (EO) and eyes closed (EC), each lasting 8 minutes. We firstly evaluated the intra- and inter-scanner reliability of ALFF, ReHo, and DC. Secondly, we measured systematic difference between two scanning visits of the same scanner as well as between two scanners. Thirdly, to account for the potential difference of intra- and inter-scanner local magnetic field inhomogeneity, we measured the difference of relative BOLD signal intensity to the mean BOLD signal intensity of the whole brain between each pair of visits. Last, we used percent amplitude of fluctuation (PerAF) to correct the difference induced by relative BOLD signal intensity. The inter-scanner reliability was much worse than intra-scanner reliability; Among the VWWB metrics, DC showed the worst (both for intra-scanner and inter-scanner comparisons). PerAF showed similar intra-scanner reliability with ALFF and the best reliability among all the 4 metrics. PerAF reduced the influence of BOLD signal intensity and hence increase the inter-scanner reliability of ALFF. For multi-center studies, inter-scanner reliability should be taken into account.

[Isolation and characterization of a halotolerant p-nitroaniline degrading strain S8].

A bacterial strain S8 was isolated from pesticide-contaminated sludge, which showed ability of utilizing p-nitroaniline as the sole source of carbon and nitrogen for growth. Based on the morphology, the physiological and biochemical characteristics, and the 16S rDNA sequence analysis, the strain was identified as Bacillus subtilis. Strain S8 showed high efficiency in p-nitroaniline degradation. 65.6% and 55.8% of p-nitroaniline (60 mg x L(-1) and 120 mg x L(-1)) were degraded by this strain within 72 hours under the optimal conditions of 31degrees C and pH 6.0. Besides, strain S8 degraded 49.5% p-nitroaniline in 7% NaCl and 27.4% p-nitroaniline in 10% NaCl (72 h), which showed that the strain S8 had a high salinity tolerance. When the LC-MS method was used for identification of the biodegradation products, six kinds of degradation products were found, two of which were identified as phenol and hydroquinone. To date, this is the first report on the degradation of p-nitroaniline by Bacillus subtilis. These results suggest that S8 could be a potential candidate for treating p-nitroaniline-contaminated saline wastewater.

Biodegradation of nitrobenzene in a lysogeny broth medium by a novel halophilic bacterium Bacillus licheniformis.

The Bacillus licheniformis strain YX2, a novel nitrobenzene-degrading halophilic bacterium, was isolated from active sludge obtained from a pesticide factory. Strain YX2 can withstand highly acidic and alkaline conditions and high temperatures. Degradation of nitrobenzene (200mgL(-1)) by YX2 exceeded 70% after 72h in lysogeny broth medium (pH 4-9). Under optimal degradation conditions (33°C, pH 7 in LB medium) YX2 degraded 50, 100, 200, and 600mgL(-1) nitrobenzene within 36, 36, 72, and 156h, respectively. Even in the presence of benzene, phenol or aniline, strain YX2 efficiently degraded nitrobenzene. Furthermore, strain YX2 completely degraded 600mgL(-1) nitrobenzene in 7% NaCl (w/w). Thus, our data show that strain YX2 may have promise for removing nitrobenzene from complex wastewaters with high salinity and variable pH.

[Biodegradation of nitrobenzene by a halophilic Myroides odoratimimus strain Y6].

Aimed at efficient remediation of nitrobenzene-contaminated saline wastewater, the nitrobenzene-degrading characteristics of a Myroides odoratimimus strain Y6 were studied and analyzed. The effects of temperature, pH, initial concentration of nitrobenzene, inoculum concentration and culture type on the biodegradation of nitrobenzene by strain Y6 under saline conditions were studied. Strain Y6 showed the highest efficiency of nitrobenzene degradation in 7% NaC1 (mass fraction). The optimal conditions for the biodegradation of nitrobenzene by strain Y6 were at pH 6.0, 28 degrees C and D600 = 1. With initial concentrations of 100 and 200 mg.L-1, 97.5% and 65.7% of nitrobenzene were transformed after 168 h in 7% NaCL, respectively. Three kinds of additional compounds, glucose, starch and glycerin were tested to choose a favorite carbon source for the co-metabolism of strain Y6. The results showed that all these three compounds could promote nitrobenzene biodegradation and cell growth. And the rate of degradation could increase to 93.3% ,with 800 mg.L-1 glucose as the primary substrate. These results suggest that strain Y6 could be a potential candidate for treating nitrobenzene-contaminated saline wastewater. To date, this is the only study on the degradation of nitrobenzene by M. odoratimimus.