Concomitant induction to few-layer and 1T-rich two-dimensional MoS2 by rigid segment-containing polysulfide as a sulfur source and in situ intercalator.

Few-layer and 1T-rich MoS2 is synthesized by a one-step solvothermal process using a rigid segment-containing polysulfide as a concomitant sulfur source and in situ intercalator. The prepared MoS2 displays superior hydrogen evolution reaction activity, providing a facile and mild approach for the development of high performing MoS2 and other two-dimensional lamellar materials.

N-doped carbon-coated ultrasmall Nb2O5 nanocomposite with excellent long cyclability for sodium storage.

Niobium pentoxide (Nb2O5) has drawn significant interest as a promising anode for sodium ion batteries (SIBs) due to its large interplanar lattice spacing and relatively high diffusion efficiency. However, the intrinsic drawbacks of low electrical conductivity and substantial volume change greatly impede its practical applications in large-scale energy storage systems. In this work, ultrasmall Nb2O5 nanoparticles wrapped with nitrogen-doped carbon (denoted as Nb2O5@NC) were delicately synthesized via a facile sol-gel method and subsequent heat treatment. The unique structure of ultrasmall Nb2O5 nanoparticles in a carbonaceous matrix can not only effectively shorten the transmission distance for both ions/electrons but also relieve the strain and stress caused by volume variation during the sodiation/desodiation process. In addition, the synergistic effect of nitrogen doping and carbon coating can further improve the electronic conductivity and pseudocapacitive behavior of the active materials, thus promoting the rapid electrochemical reaction kinetics of the Nb2O5@NC composite. The obtained 600-Nb2O5@NC-2 anode exhibits superior rate capability and outstanding cycling stability, delivering a reversible capacity of 196 mA h g-1 at 1 A g-1 after 1000 cycles. Even at high current densities of 5 A g-1 and 10 A g-1, the long-life cycling tests show that the reversible capacities still remain at 128.4 mA h g-1 and 95.9 mA h g-1 after 3000 cycles, respectively, which is the best performance of Nb2O5-based anodes at high current densities so far. These results indicate that the feasible synthetic strategy of Nb2O5@NC is an effective approach to develop high-performance Nb2O5-based anodes for large-scale energy storage.

Fabrication of an N-doped mesoporous bio-carbon electrocatalyst efficient in Zn-air batteries by an in situ gas-foaming strategy.

A nitrogen doped bio-carbon catalyst with high specific surface area and a hierarchical interconnected porous structure was fabricated by an in situ gas-foaming strategy from sodium alginate and ammonium chloride. The optimized catalyst displays a fabulous ORR activity, providing a facile approach for the mass production of metal-free bio-carbon catalysts in fuel cells and metal-air batteries.

Abnormal auditory sensory gating-out in first-episode and never-medicated paranoid schizophrenia patients: an fMRI study.

Numerous electrophysiological studies have showed auditory sensory gating-out abnormalities in chronic schizophrenia with antipsychotic medication. Previous research has used functional magnetic resonance imaging (fMRI) with excellent spatial resolution to identify the neural substrates of sensory gating-out deficits revealing increased hemodynamic response in the hippocampus, thalamus and prefrontal cortex. However, such results obtained from medicated patients may be confounded by antipsychotic medication. The present study scanned 15 first-episode schizophrenia patients not yet receiving any medical treatment and 15 healthy controls matched in gender, age and education when they performed a sensory gating-out task adapted for fMRI. The symptoms of the patients were assessed with the positive and negative syndrome scale. Different from previous findings, the schizophrenia patients showed decreased activation in hippocampus and thalamus during sensory gating-out, compared with the normal controls. The results support the theory attributing abnormal sensory gating-out in schizophrenia patients to the dysfunction of hippocampus and thalamus.

Neural evidence for direct meaning access from orthography in Chinese word reading.

A fundamental issue in the study of reading is to understand the processes involved in determining word meaning from print. We used functional magnetic resonance imaging (fMRI) and scanned participants performing lexical decision tasks to discriminate between real Chinese words and non-words, presented either visually or auditorily. For the visual task, two left inferior frontal cortical regions were significantly more activated for non-words than for words, one in BA (Brodmann's area) 44/45 implied in phonological processing, and one in BA47 implied in semantic processing. For the auditory task, stronger neural activity for non-words, relative to words, was only found in BA44/45 but not in BA47. The results were interpreted to suggest that printed words in Chinese can directly activate their semantic representations, independent of an indirect, mediated pathway through phonology. In reference to related imaging studies on English, our finding implies a greater reliance on orthography in Chinese reading.

Alterations in the processing of non-drug-related affective stimuli in abstinent heroin addicts.

Long-term exposure to drug may alter the neural system associated with affective processing, as evidenced by both clinical observations and behavioral data documenting dysfunctions in emotional experiences and processing in drug addicts. Although many imaging studies examined neural responses to drug or drug-related cues in addicts, there have been few studies explicitly designed to reveal their neural abnormalities in processing non-drug-related natural affective materials. The present study asked abstinent heroin addicts and normal controls to passively view standardized affective pictures of positive, negative, or neutral valence and compared their brain activities with functional MRI. Compared to normal controls, addicts showed reduced activation in right amygdala in response to the affective pictures, consistent with previous reports of blunted subjective experience for affective stimuli in addicts. Furthermore, in two visual cortical areas BA 19 and 37, while the controls showed greater responses to positive pictures than to negative ones replicating literature findings, the addicts showed the opposite pattern. The results reveal a complex pattern of altered processing of non-drug-related affective materials in addicts showing both heightened and blunted neural responses in different brain regions and for different stimulus valence. The present study highlights the importance of brain imaging research on drug addicts' processing of affective stimuli in understanding disruptions in their emotion circuitry.

Sex-related differences in neural activity during emotion regulation.

The sex disparity in the development of depression has long been an important research topic, but the sex-related differences in neural activity during emotion regulation have been less thoroughly studied. It was hypothesized that, during the regulation of emotion, there would be more activation in the prefrontal regions implicated in cognitive processing for males, while there would be more activation in the prefrontal regions implicated in affective processing for females. This fMRI study recruited 12 females and 12 males who were required to view or to regulate the negative and positive emotion induced by some emotion-arousing pictures. During the regulation of negative emotion, both males and females had stronger activation in the left anterior cingulate gyrus, but males showed more activation in the prefrontal regions in general, including the left dorsolateral and lateral orbitofrontal gyrus as well as the right anterior cingulate gyrus, while females only showed stronger activation in the left medial orbitofrontal gyrus. For the regulation of positive emotion, both males and females showed stronger activation in the left dorsomedial prefrontal gyrus, but males were found to also have stronger activity in the left lateral orbitofrontal gyrus. It was concluded that there are common as well as sex-specific sets of brain regions involved in regulating negative and positive emotion, and the findings may have significant implications for females' vulnerability to developing depression.

Involvement of left inferior frontal gyrus in sentence-level semantic integration.

Using event-related functional MRI, we examined the involvement of the left inferior frontal gyrus (LIFG) in semantic integration in reading Chinese sentences. During scanning, Chinese readers read individually presented sentences and judged whether or not a sentence was semantically acceptable. Behaviorally, those sentences with a small degree of semantic violation were found to be more difficult to reject relative to sentences with a large degree of semantic violation, indicating that more semantic integration occurred in the former than in the latter condition. Direct contrast revealed significantly greater brain activity in the LIFG for sentences with a small violation, relative to those with a large violation, but no differences in any anterior temporal cortical areas between the two types of anomalous sentences. The results are in line with the idea that the LIFG plays a critical role in integrating individual word meanings to coherent sentence-level messages, but not with the idea that semantic integration depends on anterior temporal cortex in language comprehension.

Neural correlates of regulation of positive and negative emotions: an fmri study.

Regulation of emotion is important for adaptive social functioning and mental well-being. This functional magnetic resonance imaging study identified neural correlates of regulation of positive or negative emotion. Twelve healthy female Chinese participants performed the experimental task that required them to simply view emotional pictures or to regulate their emotions induced by these pictures while their brain activities were monitored by a 1.5 T MRI scanner. The neuroimaging findings indicate that the left superior and lateral frontal regions (BA8/9) are common neural correlates of regulation of both emotions. For regulation of positive or negative emotion, changes of BOLD responses in the prefrontal regions and the left insula are associated with regulation of positive emotion; whereas activity of the left orbitofrontal gyrus, the left superior frontal gyrus, and the anterior cingulate gyrus appears to be involved in regulation of negative emotion. According to the participants' self-report, they appeared to be more effective in regulating positive than negative emotions, which may relate to the distinct patterns of neural activity associated with regulation of the specific emotion. As a conclusion, our findings suggest that there are shared as well as valence-specific neurocognitive mechanisms underlying regulation of positive and negative emotions. Enhanced knowledge about the neural mechanisms of emotion regulation helps improve understanding of the complex interplay of emotion and cognition underlying human behaviors.

Peripheral pulmonary nodules: relationship between multi-slice spiral CT perfusion imaging and tumor angiogenesis and VEGF expression.

BACKGROUND: The aim of this study is to investigate the relationship between 16-slice spiral CT perfusion imaging and tumor angiogenesis and VEGF (vascular endothelial growth factor) expression in patients with benign and malignant pulmonary nodules, and differential diagnosis between benign and malignant pulmonary nodules. METHODS: Sixty-four patients with benign and malignant pulmonary nodules underwent 16-slice spiral CT perfusion imaging. The CT perfusion imaging was analyzed for TDC (time density curve), perfusion parametric maps, and the respective perfusion parameters. Immunohistochemical findings of MVD (microvessel density) measurement and VEGF expression was evaluated. RESULTS: The shape of the TDC of peripheral lung cancer was similar to those of inflammatory nodule. PH (peak height), PHpm/PHa (peak height ratio of pulmonary nodule to aorta), BF (blood flow), BV (blood volume) value of peripheral lung cancer and inflammatory nodule were not statistically significant (all P > 0.05). Both showed significantly higher PH, PHpm/PHa, BF, BV value than those of benign nodule (all P < 0.05). Peripheral lung cancer showed significantly higher PS (permeability surface) value than that of inflammatory nodule and benign nodule (all P < 0.05). BV, BF, PS, MTT, PH, PHpm/PHa, and MVD among three groups of peripheral lung cancers were not significantly (all P > 0.05). In the case of adenocarcinoma, BV, BF, PS, PHpm/PHa, and MVD between poorly and well differentiation and between poorly and moderately differentiation were statistically significant (all P < 0.05). The peripheral lung cancers with VEGF positive expression showed significantly higher PH, PHpm/PHa, BF, BV, PS, and MVD value than those of the peripheral lung cancer with VEGF negative expression, and than those of benign nodule with VEGF positive expression (all P < 0.05). When investigating VEGF negative expression, it is found that PH, PHpm/PHa, and MVD of inflammatory nodule were significantly higher than those of peripheral lung cancer, PS of inflammatory nodule were significantly lower than that of peripheral lung cancer (all P < 0.05). PH, PHpm/PHa, BF, and BV of benign nodule were significantly lower than those of inflammatory nodule (all P < 0.05), rather than PS and MTT (mean transit time) (all P > 0.05). PH, PHpm/PHa, BV, and PS of benign nodule were significantly lower than those of peripheral lung cancer (all P < 0.05). In the case of VEGF positive expression, MVD was positively correlated with PH, PHpm/PHa, BF, BV, and PS of peripheral lung cancer and PS of benign nodule (all P < 0.05). CONCLUSION: Multi-slice spiral CT perfusion imaging closely correlated with tumor angiogenesis and reflected MVD measurement and VEGF expression. It provided not only a non-invasive method of quantitative assessment for blood flow patterns of peripheral pulmonary nodules but also an applicable diagnostic method for peripheral pulmonary nodules.

An electrophysiological signature for proactive interference resolution in working memory.

We used event-related potentials (ERPs) to study the temporal dynamics of proactive interference in working memory. Participants performed a Sternberg item-recognition task to determine whether a probe was in a target memory set. Familiar negative probes were found to be more difficult to reject than less familiar ones. A fronto-central N2 component peaking around 300 ms post-probe-onset differentiated among target probes, familiar and less familiar non-target probes. The study identifies N2 as the ERP signature for proactive interference resolution. It also indicates that the resolution process occurs in the same time window as target/non-target discrimination and provides the first piece of electrophysiological evidence supporting a recent interference resolution model based on localization data [Jonides, J., Nee, D.E., 2006. Brain mechanisms of proactive interference in working memory. Neuroscience 139, 181-193].

Neural activities for negative priming with affective stimuli: an fMRI study.

Negative priming refers to the slowing down in reaction time to a stimulus that is either the same as, or related to, a distracting stimulus that has been ignored by people in an immediately preceding trial. It can be used as an index to examine the extent to which people are able to disengage attention or even ignore a distracting stimulus. In this fMRI study, with healthy Mandarin-speaking Chinese participants, we replicated the basic negative priming effect with affectively neutral words. Negative priming was associated with increased activities in the anterior cingulate cortex and the insula, a result that supports the inhibition account of negative priming. We observed that the negative priming effect was attenuated by negative affective words, relative to neutral words, suggesting that subjects' inhibition of negative information was compromised. Such attenuation of negative priming by negative affective words was associated with increased activities in the ventrolateral and medial frontal regions, the hippocampus, and supplementary motor areas. These observations indicate that specific frontal and subcortical regions take part in attention orientation toward negative-affect information.

Broca's area plays a role in syntactic processing during Chinese reading comprehension.

Event-related functional magnetic resonance imaging (ER-fMRI) was adopted to examine brain activation of syntactic processing in reading logographic Chinese. While fMRI data were obtained, 15 readers of Chinese read individually presented sentences and performed semantic congruency judgments on three kinds of sentences: Congruous sentences (CON), sentences with a semantic violation (SEM), and sentences with both semantic and syntactic violations (SEM+SYN). The two types of incongruous sentences were matched in the degree of semantic plausibility. Three brain regions were identified showing significantly different levels of percent signal change across the three conditions, including BA44 in the left inferior frontal gyrus (IFG) and both BA9 and BA10/46 in the left middle frontal gyrus (MFG). Furthermore, the mean percent signal change in the left BA44 observed in the SEM+SYN condition was significantly stronger than that in either the SEM or the CON condition, while the latter two conditions were at a similar level, implying an important role of this area in Chinese syntactic processing. These results, in conjunction with those found in alphabetic scripts, suggest that there are some common neural substrates underlie syntactic processing across distinctive writing systems such as the logographic Chinese and the alphabetic English.

Verbal working memory deficits in abstinent heroin abusers.

BACKGROUND: A prevailing belief is that opioids tend not to impair cognitive performance in opioid-dependent users. However, the impact of heroin abuse on verbal memory, especially on working memory, is not well studied and the results available are inconsistent. OBJECTIVE: This study was carried out to test the hypothesis that abstinent heroin abusers have intact working memory capacity. METHODS: N-back task and backward digit span task were used to measure the verbal working memory capacity in 28 abstinent heroin abusers and 25 controls matched for age, education level and gender. Forward digit span task was used as a control task to measure short-term memory capacity. RESULTS: Compared with the control subjects, heroin abusers showed normal backward/forward digit spans but significant performance impairment in the n-back task. CONCLUSION: Abstinent heroin abusers have intact short-term memory capacity but impaired verbal working memory capacity.

Neural systems and time course of proactive interference in working memory.

The storage of information in working memory suffers as a function of proactive interference. Many works using neuroimaging technique have been done to reveal the brain mechanism of interference resolution. However, less is yet known about the time course of this process. Event-related potential method(ERP) and standardized Low Resolution Brain Electromagnetic Tomography method (sLORETA) were used in this study to discover the time course of interference resolution in working memory. The anterior P2 was thought to reflect interference resolution and if so, this process occurred earlier in working memory than in long-term memory.

Similar brain activation patterns for writing logographic and phonetic symbols in Chinese.

This event-related functional MRI study examined the neural correlates for Chinese writing, by comparing the writing of logographic characters and that of pinyin, a phonetic notation system for Chinese characters. The temporal profile of the activations indicated that the middle frontal gyrus, superior parietal lobule, and posterior inferior temporal gyrus reflected more central processes for writing. Although pinyin writing elicited greater activity overall than character writing, the critical finding is that the two types of symbols recruited essentially the same brain regions. The results were compared with studies in Japanese showing dissociation between logographic kanji and phonetic kana writing and frequency of use was suggested to be an important factor in accounting for result differences across the two writing systems.

Peripheral lung cancer: relationship between multi-slice spiral CT perfusion imaging and tumor angiogenesis and cyclin D1 expression.

The aim of this study was to investigate the relationship between 16-slice spiral CT perfusion imaging and tumor angiogenesis and cyclin D1 expression in patients with peripheral lung cancer. Fifty-eight patients with peripheral lung cancer underwent 16-slice spiral CT perfusion imaging. The CT perfusion imaging was analyzed for time density curve (TDC), perfusion parametric maps, and the respective perfusion parameters. Correlation between the respective perfusion parameters and immunohistochemical findings of microvessel density measurement and cyclin D1 expression was evaluated.

Changes of dopamine transporter function in striatum during acute morphine addiction and its abstinence in rhesus monkey.

BACKGROUND: Although dopamine transporter (DAT) is essential for addiction, the effect of additive drugs on DAT function is still controversial, especially for opiates. We investigated the functional changes of dopamine transporter in striatum of rhesus monkeys during acute morphine injection and its abstinence. METHODS: Four rhesus monkeys, 6 to 9 years old, two male and two female, were examined for 12 days. Single photon emission computed tomography (SPECT) was performed with (99)T(cm)-TRODAT-1 as the radiopharmaceutical dopamine transporter agent during different stages of acute morphine injection and its abstinence. The ratios of SPECT signal between striatum and cerebellum (ST/CB) were calculated. RESULTS: The ST/CB ratio declined significantly on the first day of morphine injection and continued declining with more morphine injections. After abstinence, the ratio increased with time, but was still significantly lower on the 5th day of abstinence than the normal level. CONCLUSIONS: In rhesus monkey, acute morphine injection has both rapid and lasting effects on DAT by downregulating its function. The decline was partially reversible following morphine abstinence. The results suggest that striatum is one effective target of morphine and that the DAT function in striatum is one indicator for morphine addiction.

Thirsty heroin addicts show different fMRI activations when exposed to water-related and drug-related cues.

Relapse to drug use is frequently preceded or caused by craving, an intense desire for drug. Advances in functional brain imaging techniques make it possible to directly investigate this special mental state in vivo and non-invasively. Extant imaging studies on craving have been mostly on cocaine which is the dominant drug abused in the U.S. Employing functional MRI, we examined substance specificity of the neural circuitry underlying craving for heroin. Heroin is the primary drug abused in south-east Asia and has, particularly, become a serious social problem for China in recent years. Following abstinence from water and drug, 14 active heroin addicts (all male, mean age 33.2 years, average drug use history 7.1 years) underwent scanning inside a 1.5T Philips MR scanner during exposure to water-related, drug-related, and neutral cues. Water-related cues elicited anterior cingulate activation (Brodmann's area BA 32/24). Drug-related cues activated bilateral inferior frontal cortex (BA 44/45), confirming the critical role of prefrontal cortex in drug craving. Results suggest heroin craving may involve different neural substrates than do desire from basic physiological drives, such as thirst. As the first fMRI study of heroin craving, our study adds to the scant but much-needed brain imaging literature on heroin addiction.

Auditory evoked potentials recorded in monkeys with hallucinatory-like behaviors induced by bromocriptine.

Objective Bromocriptine and other dopamine D2 receptor agonists can affect a range of behaviors in nonhuman primates, particularly those behaviors associated with motor and mental function, such as suppressant behaviors and hallucinatory-like behaviors in monkeys. Besides bromocriptine, the dysfunction of the rapid eye movement sleep (REM) mechanism may also contribute to hallucinations. Dissociation of wakefulness, REM, and non-REM (NREM) can cause a series of psychotic symptoms. Methods We simultaneously recorded auditory evoked potentials (AEP) from five cerebral regions in monkeys during normal and psychotomimetic states to investigate and compare state-dependent changes in AEP. Results Phase reversal of peak-to-baseline amplitude of 250 ms component (PBA250) in dorsolateral prefrontal cortex was common characteristic of hallucinatory-like and REM, and that hallucinatory-like and REM shared the equivalent modulatory orderliness of the PBA250 in dorsolateral prefrontal cortex. This result suggests that hallucinatory-like and REM share an equivalent electrophysiological modulatory in dorsolateral prefrontal cortex. Conclusion These results reveal that emergence of the N250 in dorsolateral prefrontal cortex is an exclusive marker that may help to discern whether hallucinatory-like behaviors is exhibited, which suggests that dorsolateral prefrontal cortex may be the most pivotal region for exhibition of hallucinatory-like behaviors.