Preparation and research progress of lignin-based supercapacitor electrode materials.

The reserve of lignin in the biological world is the second largest biomass resource after cellulose. Lignin has the characteristics of wide sources, low cost, and rich active components. Due to environmental pollution and energy scarcity, lignin is often used as a substitute good for petrochemical products. Lignin-based functional materials can be prepared by chemical modification or compounding, which are widely used in the fields of energy storage, chemical industry, and medicine. Among them, lignin-based carbon materials have the features of stable chemical properties, large pH application range, ideal electrical conductivity, developed pore size, and high specific surface area, which have great application prospects as supercapacitor materials. This paper mainly introduces the structural properties of lignin, the methods, and mechanisms of carbonization, pore-making, and pore-expansion, as well as the research progress of lignin-based carbon materials for supercapacitors, while looking forward to the future research direction of lignin carbon materials.

Recent advances in lignin antioxidant: Antioxidant mechanism, evaluation methods, influence factors and various applications.

Lignin, a by-product of processing lignocellulosic materials, has a polyphenolic structure and can be used as an antioxidant directly or synergistically with synthetic types of antioxidants, leading to different applications. Its antioxidant mechanism is mainly related to the production of ROS, but the details need to be further investigated. The antioxidant property of lignin is mainly related to the content of phenolic hydroxyl group, but methoxy, purity will also have an effect on it. In addition, different methods to detect the antioxidant properties of lignin have different advantages and disadvantages. In this paper, the antioxidant mechanism of lignin, the methods to determine the antioxidant activity and the progress of its application in various fields are reviewed. In addition, the current research on the antioxidant properties of lignin and the hot directions are provided, and an outlook on the research into the antioxidant properties of lignin is provided to broaden its potential application areas.

Antibacterial mechanism of lignin and lignin-based antimicrobial materials in different fields.

The control of microbial infection transmission often relies on the utilization of synthetic and metal-based antimicrobial agents. However, their non-biodegradability and inadequate disposal practices lead to significant environmental contamination. To address this concern, the quest for natural alternatives has gained paramount importance. Lignin, a widely available renewable aromatic compound, emerges as a promising candidate owing to its inherent phenolic moiety, which lends itself well to acting as a natural antimicrobial agent either independently or in combination with other agents. This article provides a comprehensive account of the structure and primary classes of lignin. Additionally, it elucidates the antimicrobial mechanism of lignin, the factors influencing its efficacy, and the methods employed for its detection. Moreover, it describes the progress made in developing the antimicrobial capacity of lignin in different areas. In conclusion, this paper not only outlines the current state of research on the antimicrobial function of lignin, but also identifies challenges and future possibilities for enhancing its antimicrobial properties. This work holds great significance in the ongoing endeavor to contribute to high-impact research on natural alternatives for controlling infections and fostering environmentally conscious practices.

DES: their effect on lignin and recycling performance.

Lignocellulosic biomass raw materials are renewable resources with abundant reserves in nature, and have many advantages, such as being green, biodegradable and cheap. Lignin, one of the three significant components of lignocellulose, possesses a chemical structure rich in phenylpropane and is a primary aromatic resource for the bio-based economy. For the extraction and degradation of lignin, the most common method is the pretreatment of lignocellulose with deep eutectic solvents (DES), which have similar physicochemical properties to ionic liquids (ILs) but address the disadvantages associated with ILs (DES have the advantages of low cost, low toxicity, and non-flammability). In lignocellulose pretreatment, a large amount of solvent is generally required to achieve the desired effect. However, after treatment, a substantial volume of solvent will be wasted, and thus, the problem of the recovery and reuse of DES solution needs to be adequately solved. The methods and mechanisms of perfect DES regeneration will be discussed from the perspective of the elemental composition and features of DESs in this review, which will also outline the present DES recovery methods, such as rotary evaporation, membrane separation, freeze-drying, electrodialysis, etc. The detailed process and the advantages and disadvantages of each method since 2018 are introduced in detail. Future DES recovery methods have been prospected, and the optimization of the functional properties of DESs after recovery is discussed. It is expected to find a convenient and efficient application method for DES extraction or degradation of lignin with low energy and low cost.

Simultaneous mnemonic and predictive representations in the auditory cortex.

Recent studies have shown that stimulus history can be decoded via the use of broadband sensory impulses to reactivate mnemonic representations.1-4. However, memories of previous stimuli can also be used to form sensory predictions about upcoming stimuli.5,6 Predictive mechanisms allow the brain to create a probable model of the outside world, which can be updated when errors are detected between the model predictions and external inputs. 7-10 Direct recordings in the auditory cortex of awake mice established neural mechanisms for how encoding mechanisms might handle working memory and predictive processes without "overwriting" recent sensory events in instances where predictive mechanisms are triggered by oddballs within a sequence.11 However, it remains unclear whether mnemonic and predictive information can be decoded from cortical activity simultaneously during passive, implicit sequence processing, even in anesthetized models. Here, we recorded neural activity elicited by repeated stimulus sequences using electrocorticography (ECoG) in the auditory cortex of anesthetized rats, where events within the sequence (referred to henceforth as "vowels," for simplicity) were occasionally replaced with a broadband noise burst or omitted entirely. We show that both stimulus history and predicted stimuli can be decoded from neural responses to broadband impulses, at overlapping latencies but based on independent and uncorrelated data features. We also demonstrate that predictive representations are dynamically updated over the course of stimulation.

The precedence effect in spatial hearing manifests in cortical neural population responses.

BACKGROUND: To localize sound sources accurately in a reverberant environment, human binaural hearing strongly favors analyzing the initial wave front of sounds. Behavioral studies of this "precedence effect" have so far largely been confined to human subjects, limiting the scope of complementary physiological approaches. Similarly, physiological studies have mostly looked at neural responses in the inferior colliculus, the main relay point between the inner ear and the auditory cortex, or used modeling of cochlear auditory transduction in an attempt to identify likely underlying mechanisms. Studies capable of providing a direct comparison of neural coding and behavioral measures of sound localization under the precedence effect are lacking. RESULTS: We adapted a "temporal weighting function" paradigm previously developed to quantify the precedence effect in human for use in laboratory rats. The animals learned to lateralize click trains in which each click in the train had a different interaural time difference. Computing the "perceptual weight" of each click in the train revealed a strong onset bias, very similar to that reported for humans. Follow-on electrocorticographic recording experiments revealed that onset weighting of interaural time differences is a robust feature of the cortical population response, but interestingly, it often fails to manifest at individual cortical recording sites. CONCLUSION: While previous studies suggested that the precedence effect may be caused by early processing mechanisms in the cochlea or inhibitory circuitry in the brainstem and midbrain, our results indicate that the precedence effect is not fully developed at the level of individual recording sites in the auditory cortex, but robust and consistent precedence effects are observable only in the auditory cortex at the level of cortical population responses. This indicates that the precedence effect emerges at later cortical processing stages and is a significantly "higher order" feature than has hitherto been assumed.

Sensitivity of neural responses in the inferior colliculus to statistical features of sound textures.

Previous psychophysical studies have identified a hierarchy of time-averaged statistics which determine the identity of natural sound textures. However, it is unclear whether the neurons in the inferior colliculus (IC) are sensitive to each of these statistical features in the natural sound textures. We used 13 representative sound textures spanning the space of 3 statistics extracted from over 200 natural textures. The synthetic textures were generated by incorporating the statistical features in a step-by-step manner, in which a particular statistical feature was changed while the other statistical features remain unchanged. The extracellular activity in response to the synthetic texture stimuli was recorded in the IC of anesthetized rats. Analysis of the transient and sustained multiunit activity after each transition of statistical feature showed that the IC units were sensitive to the changes of all types of statistics, although to a varying extent. For example, we found that more neurons were sensitive to the changes in variance than that in the modulation correlations. Our results suggest that the sensitivity of the statistical features in the subcortical levels contributes to the identification and discrimination of natural sound textures.

Interaural time difference tuning in the rat inferior colliculus is predictive of behavioral sensitivity.

While a large body of literature has examined the encoding of binaural spatial cues in the auditory midbrain, studies that ask how quantitative measures of spatial tuning in midbrain neurons compare with an animal's psychoacoustic performance remain rare. Researchers have tried to explain deficits in spatial hearing in certain patient groups, such as binaural cochlear implant users, in terms of declines in apparent reductions in spatial tuning of midbrain neurons of animal models. However, the quality of spatial tuning can be quantified in many different ways, and in the absence of evidence that a given neural tuning measure correlates with psychoacoustic performance, the interpretation of such finding remains very tentative. Here, we characterize ITD tuning in the rat inferior colliculus (IC) to acoustic pulse train stimuli with varying envelopes and at varying rates, and explore whether quality of tuning correlates behavioral performance. We quantified both mutual information (MI) and neural d' as measures of ITD sensitivity. Neural d' values paralleled behavioral ones, declining with increasing click rates or when envelopes changed from rectangular to Hanning windows, and they correlated much better with behavioral performance than MI. Meanwhile, MI values were larger in an older, more experienced cohort of animals than in naive animals, but neural d' did not differ between cohorts. However, the results obtained with neural d' and MI were highly correlated when ITD values were coded simply as left or right ear leading, rather than specific ITD values. Thus, neural measures of lateralization ability (e.g. d' or left/right MI) appear to be highly predictive of psychoacoustic performance in a two-alternative forced choice task.

Microsecond interaural time difference discrimination restored by cochlear implants after neonatal deafness.

Spatial hearing in cochlear implant (CI) patients remains a major challenge, with many early deaf users reported to have no measurable sensitivity to interaural time differences (ITDs). Deprivation of binaural experience during an early critical period is often hypothesized to be the cause of this shortcoming. However, we show that neonatally deafened (ND) rats provided with precisely synchronized CI stimulation in adulthood can be trained to lateralize ITDs with essentially normal behavioral thresholds near 50 µs. Furthermore, comparable ND rats show high physiological sensitivity to ITDs immediately after binaural implantation in adulthood. Our result that ND-CI rats achieved very good behavioral ITD thresholds, while prelingually deaf human CI patients often fail to develop a useful sensitivity to ITD raises urgent questions concerning the possibility that shortcomings in technology or treatment, rather than missing input during early development, may be behind the usually poor binaural outcomes for current CI patients.

Learning boosts the decoding of sound sequences in rat auditory cortex.

Continuous acoustic streams, such as speech signals, can be chunked into segments containing reoccurring patterns (e.g., words). Noninvasive recordings of neural activity in humans suggest that chunking is underpinned by low-frequency cortical entrainment to the segment presentation rate, and modulated by prior segment experience (e.g., words belonging to a familiar language). Interestingly, previous studies suggest that also primates and rodents may be able to chunk acoustic streams. Here, we test whether neural activity in the rat auditory cortex is modulated by previous segment experience. We recorded subdural responses using electrocorticography (ECoG) from the auditory cortex of 11 anesthetized rats. Prior to recording, four rats were trained to detect familiar triplets of acoustic stimuli (artificial syllables), three were passively exposed to the triplets, while another four rats had no training experience. While low-frequency neural activity peaks were observed at the syllable level, no triplet-rate peaks were observed. Notably, in trained rats (but not in passively exposed and naïve rats), familiar triplets could be decoded more accurately than unfamiliar triplets based on neural activity in the auditory cortex. These results suggest that rats process acoustic sequences, and that their cortical activity is modulated by the training experience even under subsequent anesthesia.

Microsecond sensitivity to envelope interaural time differences in rats.

Currently, there is controversy around whether rats can use interaural time differences (ITDs) to localize sound. Here, naturalistic pulse train stimuli were used to evaluate the rat's sensitivity to onset and ongoing ITDs using a two-alternative forced choice sound lateralization task. Pulse rates between 50 Hz and 4.8 kHz with rectangular or Hanning windows were delivered with ITDs between ±175 µs over a near-field acoustic setup. Similar to other mammals, rats performed with 75% accuracy at ∼50 µs ITD, demonstrating that rats are highly sensitive to envelope ITDs.

Effects of different extracts of kanggushu on osteoporosis in model rats and the underlying mechanisms.

OBJECTIVE: To investigate the preventive effects and possible underlying mechanism of different extracts of Kanggushu () on osteoporosis in ovariectomized rats. METHODS: One hundred and sixtyfive female SD rats were divided into 11 groups: control, sham, model, Xianling Gubao Capsule (), nilestriol, Kanggushu aqueous extract high-, medium-, and low-dose and suet extract high-, medium-, and low-dose groups. The osteoporosis model was made by ovariectomizing the rats. The latter 8 groups were administered intragastricly with Xianling Gubao Capsule, nilestriol, Kanggushu aqueous extract and suet extract for 12 weeks, respectively, while the other 3 groups were administered orally saline. The whole body bone mineral density, bone mineral content, organ coefficient of uterus, serum estradiol and alkaline phosphatase contents, blood calcium, phosphorus, interleukin 6 and bone Gla-protein levels after treatment were monitored. Additionally, three-point bending test of femur, HE staining, and scanning electron microscope were performed to explore the pharmacodynamics and underlying mechanisms. RESULTS: In comparison with ovariectomized rats of model group, Kanggushu aqueous extract high-dose resulted in an increased bone mineral density, bone mineral content and organ coefficient of uterus, improved estradiol level, and improved maximum load and structural stiffness (P<0.05 or P<0.01). Two-dimensional and three-dimensional trabecular structure was also observed under HE staining and scanning electron microscopy, and the number and thickness of trabecular bone in Kanggushu aqueous extract high-dose group was significantly increased compared to the model group, while the lipid droplets in bone marrow cavity were significantly less. However, there were no significant differences in blood calcium, total serum alkaline phosphatase and bone Gla protein among different treatment groups. Overall, the osteoprotective effects of Kanggushu aqueous extract were comparable to those of nilestriol and were significantly more effective than those of Xianling Gubao Capsule. CONCLUSION: The preventive effects of Kanggushu aqueous extract might be partly due to the increased estradiol level, accelerated restoration of bone trabecular reticulate structure, and accordingly increased bone mineral density in osteoporosis rats.

Protective effects of gypenosides against fatty liver disease induced by high fat and cholesterol diet and alcohol in rats.

In the present study, the protective effects of gypenosides from Gynostemma pentaphyllum on fatty liver disease (FLD) were examined in rats treated with high fat and cholesterol diet and alcohol. Male SD rats were divided into seven groups: control, model, lovastatin, silymarin, gypenosides high-, medium- and low-treatment groups. The latter 6 groups were fed high-fat and cholesterol diet and administered alcohol intragastricly once a day. Body weight was measured every week for 10 weeks, and the hepatic index was measured after 10 weeks. Compared with model group, levels of serum triglyceride (TG), total cholesterol (TC), free fatty acid (FFA), and low density lipoprotein cholesterol (LDL-C) level, malondialdehyde (MDA), serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activity, and hepatocyte apoptosis were significantly decreased in gypenosides groups; while serum high density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) activity in both serum and hepatic tissue and mRNA and protein level of peroxisome proliferator-activated receptor α (PPAR-α) were significantly increased. Moreover, hepatic steatosis and mitochondrial damage were improved. These results suggested that gypenosides could prevent liver fatty degeneration in fatty liver disease through modulating lipid metabolism, ameliorating liver dysfunction and reducing oxidative stress.

Relationship between HPLC fingerprints and in vivo pharmacological effects of a traditional Chinese medicine: Radix Angelicae Dahuricae.

We report the fingerprint development of a traditional Chinese medicine Radix Angelicae Dahuricae root and the correlation of the fingerprint peaks with its in vivo pharmacological effects. The high-performance liquid chromatography (HPLC) methods with the computer aided similarity evaluation were validated and used in serial pharmacological studies in mice. The major constituents of R. Angelicae Dahuricae were successfully separated by the HPLC methods, and the effects of sedation and analgesia were mainly related to the chromatographic peaks of group II. The anti-inflammatory, anti-heat stroke and anti-endotoxemic effects were mainly related to the peaks in group III. These results indicated a correlation between the HPLC fingerprints in groups and the pharmacological effects of R. Angelicae Dahuricae. This simple and accurate method can be used for the identification of the active components of R. Angelicae Dahuricae and for the quality control of its pharmaceutical preparations.