Detecting the exponential relaxation spectrum in glasses by high-precision nanocalorimetry.

Nonexponential relaxations are universal characteristics for glassy materials. There is a well-known hypothesis that nonexponential relaxation peaks are composed of a series of exponential events, which have not been verified. In this Letter, we discover the exponential relaxation events during the recovery process using a high-precision nanocalorimetry, which are universal for metallic glasses and organic glasses. The relaxation peaks can be well fitted by the exponential Debye function with a single activation energy. The activation energy covers a broad range from α relaxation to ß relaxation and even the fast γ/ß' relaxation. We obtain the complete spectrum of the exponential relaxation peaks over a wide temperature range from 0.63Tg to 1.03Tg, which provides solid evidence that nonexponential relaxation peaks can be decomposed into exponential relaxation units. Furthermore, the contribution of different relaxation modes in the nonequilibrium enthalpy space is measured. These results open a door for developing the thermodynamics of nonequilibrium physics and for precisely modulating the properties of glasses by controlling the relaxation modes.

Lithium and exercise ameliorate insulin-deficient hyperglycemia by independently attenuating pancreatic α-cell mass and hepatic gluconeogenesis.

As in type 1 diabetes, the loss of pancreatic ß-cells leads to insulin deficiency and the subsequent development of hyperglycemia. Exercise has been proposed as a viable remedy for hyperglycemia. Lithium, which has been used as a treatment for bipolar disorder, has also been shown to improve glucose homeostasis under the conditions of obesity and type 2 diabetes by enhancing the effects of exercise on the skeletal muscles. In this study, we demonstrated that unlike in obesity and type 2 diabetic conditions, under the condition of insulin-deficient type 1 diabetes, lithium administration attenuated pancreatic a-cell mass without altering insulin-secreting ß-cell mass, implying a selective impact on glucagon production. Additionally, we also documented that lithium downregulated the hepatic gluconeogenic program by decreasing G6Pase protein levels and upregulating AMPK activity. These findings suggest that lithium's effect on glucose metabolism in type 1 diabetes is mediated through a different mechanism than those associated with exerciseinduced metabolic changes in the muscle. Therefore, our research presents the novel therapeutic potential of lithium in the treatment of type 1 diabetes, which can be utilized along with insulin and independently of exercise.

Endoplasmic reticulum stress in pancreatic ß cells induces incretin desensitization and ß-cell dysfunction via ATF4-mediated PDE4D expression.

Pancreatic ß-cell dysfunction and eventual loss are key steps in the progression of type 2 diabetes (T2D). Endoplasmic reticulum (ER) stress responses, especially those mediated by the protein kinase RNA-like ER kinase and activating transcription factor 4 (PERK-ATF4) pathway, have been implicated in promoting these ß-cell pathologies. However, the exact molecular events surrounding the role of the PERK-ATF4 pathway in ß-cell dysfunction remain unknown. Here, we report our discovery that ATF4 promotes the expression of PDE4D, which disrupts ß-cell function via a downregulation of cAMP signaling. We found that ß-cell-specific transgenic expression of ATF4 led to early ß-cell dysfunction and loss, a phenotype that resembles accelerated T2D. Expression of ATF4, rather than C/EBP homologous protein (CHOP), promoted PDE4D expression, reduced cAMP signaling, and attenuated responses to incretins and elevated glucose. Furthermore, we found that ß-cells of leptin receptor-deficient diabetic (db/db) mice had elevated nuclear localization of ATF4 and PDE4D expression, accompanied by impaired ß-cell function. Accordingly, pharmacological inhibition of the ATF4 pathway attenuated PDE4D expression in the islets and promoted incretin-simulated glucose tolerance and insulin secretion in db/db mice. Finally, we found that inhibiting PDE4 activity with selective pharmacological inhibitors improved ß-cell function in both db/db mice and ß-cell-specific ATF4 transgenic mice. In summary, our results indicate that ER stress causes ß-cell failure via ATF4-mediated PDE4D production, suggesting the ATF4-PDE4D pathway could be a therapeutic target for protecting ß-cell function during the progression of T2D.NEW & NOTEWORTHY Endoplasmic reticulum stress has been implied to cause multiple ß-cell pathologies during the progression of type 2 diabetes (T2D). However, the precise molecular events underlying this remain unknown. Here, we discovered that elevated ATF4 activity, which was seen in T2D ß cells, attenuated ß-cell proliferation and impaired insulin secretion via PDE4D-mediated downregulation of cAMP signaling. Additionally, we demonstrated that pharmacological inhibition of the ATF4 pathway or PDE4D activity alleviated ß-cell dysfunction, suggesting its therapeutic usefulness against T2D.

Safety and success of transvenous lead extraction using excimer laser sheaths: a meta-analysis of over 1700 patients.

AIMS: While numerous studies have demonstrated favourable safety and efficacy of the excimer laser sheath for transvenous lead extraction (TLE) in smaller cohorts, comprehensive large-scale investigations with contemporary data remain scarce. This study aims to evaluate the safety and performance of laser-assisted TLE through a meta-analysis of contemporary data. METHODS AND RESULTS: A systematic literature search was conducted to identify articles that assessed the safety and performance of the spectranetics laser sheath (SLS) II and GlideLight Excimer laser sheaths in TLE procedures between 1 April 2016 and 31 March 2021. Safety outcomes included procedure-related death and major/minor complications. Performance outcomes included procedural and clinical success rates. A random-effects, inverse-variance-weighting meta-analysis was performed to obtain the weighted average of the evaluated outcomes. In total, 17 articles were identified and evaluated, including 1729 patients with 2887 leads. Each patient, on average, had 2.3 ± 0.3 leads with a dwell time of 7.9 ± 3.0 years. The TLE procedural successes rate was 96.8% [1440/1505; 95% CI: (94.9-98.2%)] per patient and 96.3% [1447/1501; 95% CI: (94.8-97.4%)] per lead, and the clinical success rate per patient was 98.3% [989/1010, 95% CI: (97.4-99.0%)]. The procedure-related death rate was 0.08% [7/1729, 95% CI: (0.00%, 0.34%)], with major and minor complication rates of 1.9% [41/1729; 95% CI: (1.2-2.8%)] and 1.9% [58/1729; 95% CI: (0.8-3.6%)], respectively. CONCLUSION: This meta-analysis demonstrated that excimer laser sheath-assisted TLE has high success and low procedural mortality rates. It provides clinicians with a reliable and valuable resource for extracting indwelling cardiac leads which require advanced extraction techniques.

Connexin 43 mediated the angiogenesis of buyang huanwu decoction via vascular endothelial growth factor and angiopoietin-1 after ischemic stroke.

Buyang Huanwu decoction (BYHWD), a classical prescription for ischemic stroke, has been reported to promote angiogenesis after focal ischemia. However, the mechanisms of the contribution of BYHWD on angiogenesis are still unclear. Connexin 43 (Cx43) played important roles in the functions of neurogliovascular unit. Therefore, the aim of this study was to explore the potential role of Cx43 in angiogenesis of the ischemic brain after BYHWD treatment. Middle cerebral artery occlusion (MCAO) was used to establish the model of focal ischemia. BYHWD was administrated intragastrically twice a day after MCAO with or without Gap26 (a specific Cx43 inhibitor). Western blot, neurological deficits, immunofluorescent staining, and Evans blue dye were used to confirm the role of Cx43 in angiogenesis after BYHWD treatment. The expression levels of total Cx43 and phosphorylated Cx43 were upregulated by BYHWD and peaked at 7 days post MCAO. Inhibition of Cx43 with Gap26 significantly attenuated the protective role of BYHWD in neurological behavior. BYHWD treatment promoted angiogenesis demonstrated by increased microvascular density, upregulated vascular endothelial growth factor (VEGF), and angiopoietin-1 (Ang-1), while inhibition of Cx43 with Gap26 attenuated these effects of BYHWD. In addition, Gap26 inhibited the beneficial effect of BYHWD on blood-brain barrier (BBB) integrity. These results suggested that Cx43 mediated the angiogenesis of BYHWD via VEGF and Ang-1 after focal ischemic stroke.

Overexpression of two CDPKs from wild Chinese grapevine enhances powdery mildew resistance in Vitis vinifera and Arabidopsis.

Calcium-dependent protein kinases (CDPKs) play vital roles in metabolic regulations and stimuli responses in plants. However, little is known about their function in grapevine. Here, we report that VpCDPK9 and VpCDPK13, two paralogous CDPKs from Vitis pseudoreticulata accession Baihe-35-1, appear to positively regulate powdery mildew resistance. The transcription of them in leaves of 'Baihe-35-1' were differentially induced upon powdery mildew infection. Overexpression of VpCDPK9-YFP or VpCDPK13-YFP in the V. vinifera susceptible cultivar Thompson Seedless resulted in enhanced resistance to powdery mildew (YFP, yellow fluorescent protein). This might be due to elevation of SA and ethylene production, and excess accumulation of H2 O2 and callose in penetrated epidermal cells and/or the mesophyll cells underneath. Ectopic expression of VpCDPK9-YFP in Arabidopsis resulted in varied degrees of reduced stature, pre-mature senescence and enhanced powdery mildew resistance. However, these phenotypes were abolished in VpCDPK9-YFP transgenic lines impaired in SA signaling (pad4sid2) or ethylene signaling (ein2). Moreover, both of VpCDPK9 and VpCDPK13 were found to interact with and potentially phosphorylate VpMAPK3, VpMAPK6, VpACS1 and VpACS2 in vivo (ACS, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase; MAPK, mitogen-activated protein kinase). These results suggest that VpCDPK9 and VpCDPK13 contribute to powdery mildew resistance via positively regulating SA and ethylene signaling in grapevine.

Cellular Stress-Modulating Drugs Can Potentially Be Identified by in Silico Screening with Connectivity Map (CMap).

Accompanied by increased life span, aging-associated diseases, such as metabolic diseases and cancers, have become serious health threats. Recent studies have documented that aging-associated diseases are caused by prolonged cellular stresses such as endoplasmic reticulum (ER) stress, mitochondrial stress, and oxidative stress. Thus, ameliorating cellular stresses could be an effective approach to treat aging-associated diseases and, more importantly, to prevent such diseases from happening. However, cellular stresses and their molecular responses within the cell are typically mediated by a variety of factors encompassing different signaling pathways. Therefore, a target-based drug discovery method currently being used widely (reverse pharmacology) may not be adequate to uncover novel drugs targeting cellular stresses and related diseases. The connectivity map (CMap) is an online pharmacogenomic database cataloging gene expression data from cultured cells treated individually with various chemicals, including a variety of phytochemicals. Moreover, by querying through CMap, researchers may screen registered chemicals in silico and obtain the likelihood of drugs showing a similar gene expression profile with desired and chemopreventive conditions. Thus, CMap is an effective genome-based tool to discover novel chemopreventive drugs.

Effects of Voluntary Locomotion and Calcitonin Gene-Related Peptide on the Dynamics of Single Dural Vessels in Awake Mice.

The dura mater is a vascularized membrane surrounding the brain and is heavily innervated by sensory nerves. Our knowledge of the dural vasculature has been limited to pathological conditions, such as headaches, but little is known about the dural blood flow regulation during behavior. To better understand the dynamics of dural vessels during behavior, we used two-photon laser scanning microscopy (2PLSM) to measure the diameter changes of single dural and pial vessels in the awake mouse during voluntary locomotion. Surprisingly, we found that voluntary locomotion drove the constriction of dural vessels, and the dynamics of these constrictions could be captured with a linear convolution model. Dural vessel constrictions did not mirror the large increases in intracranial pressure (ICP) during locomotion, indicating that dural vessel constriction was not caused passively by compression. To study how behaviorally driven dynamics of dural vessels might be altered in pathological states, we injected the vasodilator calcitonin gene-related peptide (CGRP), which induces headache in humans. CGRP dilated dural, but not pial, vessels and significantly reduced spontaneous locomotion but did not block locomotion-induced constrictions in dural vessels. Sumatriptan, a drug commonly used to treat headaches, blocked the vascular and behavioral the effects of CGRP. These findings suggest that, in the awake animal, the diameters of dural vessels are regulated dynamically during behavior and during drug-induced pathological states.

Time to wake up: Studying neurovascular coupling and brain-wide circuit function in the un-anesthetized animal.

Functional magnetic resonance imaging (fMRI) has allowed the noninvasive study of task-based and resting-state brain dynamics in humans by inferring neural activity from blood-oxygenation-level dependent (BOLD) signal changes. An accurate interpretation of the hemodynamic changes that underlie fMRI signals depends on the understanding of the quantitative relationship between changes in neural activity and changes in cerebral blood flow, oxygenation and volume. While there has been extensive study of neurovascular coupling in anesthetized animal models, anesthesia causes large disruptions of brain metabolism, neural responsiveness and cardiovascular function. Here, we review work showing that neurovascular coupling and brain circuit function in the awake animal are profoundly different from those in the anesthetized state. We argue that the time is right to study neurovascular coupling and brain circuit function in the awake animal to bridge the physiological mechanisms that underlie animal and human neuroimaging signals, and to interpret them in light of underlying neural mechanisms. Lastly, we discuss recent experimental innovations that have enabled the study of neurovascular coupling and brain-wide circuit function in un-anesthetized and behaving animal models.

Purification and characteristics of a novel bacteriocin produced by Enterococcus faecalis L11 isolated from Chinese traditional fermented cucumber.

OBJECTIVE: To purify and characterize a novel bacteriocin with broad inhibitory spectrum produced by an isolate of Enterococcus faecalis from Chinese fermented cucumber. RESULTS: E. faecalis L11 produced a bacteriocin with antimicrobial activity against both Escherichia coli and Staphylococcus aureus. The amino acid sequence of the purified bacteriocin, enterocin L11, was assayed by Edman degradation method. It differs from other class II bacteriocins and exhibited a broad antimicrobial activity against not only Gram-positive bacteria, including Bacillus subtilis, S. aureus, Listeria monocytogenes, Sarcina flava, Lactobacillus acidophilus, L. plantarum, L. delbrueckii subsp. delbrueckii, L. delbrueckii subsp. bulgaricus and Streptococcus thermophilus, but also some Gram-negative bacteria including Salmonella typhimurium, E. coli and Shigella flexneri. Enterocin L11 retained 91 % of its activity after holding at 121 °C for 30 min. It was also resistant to acids and alkalis. CONCLUSIONS: Enterocin L11 is a novel broad-spectrum Class II bacteriocin produced by E. faecalis L11, and may have potential as a food biopreservative.

Quantitative separation of arterial and venous cerebral blood volume increases during voluntary locomotion.

Voluntary locomotion is accompanied by large increases in cortical activity and localized increases in cerebral blood volume (CBV). We sought to quantitatively determine the spatial and temporal dynamics of voluntary locomotion-evoked cerebral hemodynamic changes. We measured single vessel dilations using two-photon microscopy and cortex-wide changes in CBV-related signal using intrinsic optical signal (IOS) imaging in head-fixed mice freely locomoting on a spherical treadmill. During bouts of locomotion, arteries dilated rapidly, while veins distended slightly and recovered slowly. The dynamics of diameter changes of both vessel types could be captured using a simple linear convolution model. Using these single vessel measurements, we developed a novel analysis approach to separate out spatially and temporally distinct arterial and venous components of the location-specific hemodynamic response functions (HRF) for IOS. The HRF of each pixel of was well fit by a sum of a fast arterial and a slow venous component. The HRFs of pixels in the limb representations of somatosensory cortex had a large arterial contribution, while in the frontal cortex the arterial contribution to the HRF was negligible. The venous contribution was much less localized, and was substantial in the frontal cortex. The spatial pattern and amplitude of these HRFs in response to locomotion in the cortex were robust across imaging sessions. Separating the more localized arterial component from the diffuse venous signals will be useful for dealing with the dynamic signals generated by naturalistic stimuli.

Mechanical restriction of intracortical vessel dilation by brain tissue sculpts the hemodynamic response.

Understanding the spatial dynamics of dilation in the cerebral vasculature is essential for deciphering the vascular basis of hemodynamic signals in the brain. We used two-photon microscopy to image neural activity and vascular dynamics in the somatosensory cortex of awake behaving mice during voluntary locomotion. Arterial dilations within the histologically-defined forelimb/hindlimb (FL/HL) representation were larger than arterial dilations in the somatosensory cortex immediately outside the FL/HL representation, demonstrating that the vascular response during natural behaviors was spatially localized. Surprisingly, we found that locomotion drove dilations in surface vessels that were nearly three times the amplitude of intracortical vessel dilations. The smaller dilations of the intracortical arterioles were not due to saturation of dilation. Anatomical imaging revealed that, unlike surface vessels, intracortical vessels were tightly enclosed by brain tissue. A mathematical model showed that mechanical restriction by the brain tissue surrounding intracortical vessels could account for the reduced amplitude of intracortical vessel dilation relative to surface vessels. Thus, under normal conditions, the mechanical properties of the brain may play an important role in sculpting the laminar differences of hemodynamic responses.

Genome-wide Identification and Expression Analysis of the CDPK Gene Family in Grape, Vitis spp.

BACKGROUND: Calcium-dependent protein kinases (CDPKs) play vital roles in plant growth and development, biotic and abiotic stress responses, and hormone signaling. Little is known about the CDPK gene family in grapevine. RESULTS: In this study, we performed a genome-wide analysis of the 12X grape genome (Vitis vinifera) and identified nineteen CDPK genes. Comparison of the structures of grape CDPK genes allowed us to examine their functional conservation and differentiation. Segmentally duplicated grape CDPK genes showed high structural conservation and contributed to gene family expansion. Additional comparisons between grape and Arabidopsis thaliana demonstrated that several grape CDPK genes occured in the corresponding syntenic blocks of Arabidopsis, suggesting that these genes arose before the divergence of grapevine and Arabidopsis. Phylogenetic analysis divided the grape CDPK genes into four groups. Furthermore, we examined the expression of the corresponding nineteen homologous CDPK genes in the Chinese wild grape (Vitis pseudoreticulata) under various conditions, including biotic stress, abiotic stress, and hormone treatments. The expression profiles derived from reverse transcription and quantitative PCR suggested that a large number of VpCDPKs responded to various stimuli on the transcriptional level, indicating their versatile roles in the responses to biotic and abiotic stresses. Moreover, we examined the subcellular localization of VpCDPKs by transiently expressing six VpCDPK-GFP fusion proteins in Arabidopsis mesophyll protoplasts; this revealed high variability consistent with potential functional differences. CONCLUSIONS: Taken as a whole, our data provide significant insights into the evolution and function of grape CDPKs and a framework for future investigation of grape CDPK genes.

Purification, characterization, and in vitro digestion of novel antioxidant peptides from chicken blood hemoglobin.

The study aimed to purify and characterize antioxidant peptides from chicken blood hemoglobin hydrolysate. The fraction M2  (< 3 KDa) with the strongest antioxidant activity was isolated by ultrafiltration, and its DPPH (1,1-diphenyl-2-picryl-hydrazyl radical) free radical scavenging rate, ABTS [2,2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate)] free radical scavenging rate, and iron ion chelation activity were 82.91%, 77.49%, and 80.99%, respectively. After in vitro digestion, the antioxidant capacity of chicken blood hydrolysate was significantly higher than that before digestion (p < 0.05). M2 exhibited the strongest antioxidant activity after stomach digestion, with a DPPH radical scavenging rate and iron ion chelating power of 82.91% and 79.61%, respectively. Component A was purified from M2 by Sephadex G-25 gel chromatography. The peptide sequences were identified by LC-MS/MS from fraction A, and four peptides, AEDKKLIQ (944.54 Da), APAPAAK (625.36 Da), LSDLHAHKL (1033.57 Da), and LSNLHAYNL (1044.54 Da) were synthesized using the solid-phase peptide method, among which APAPAAK was a novel antioxidant peptide. Molecular docking was used to simulate the binding of these four peptides to the key active site of Keap1 via hydrogen bonding. This study suggests that chicken blood may provide a new natural source of antioxidant peptides.

ER stress and unfolded protein response (UPR) signaling modulate GLP-1 receptor signaling in the pancreatic islets.

Insulin is essential for maintaining normoglycemia and is predominantly secreted in response to glucose stimulation by ß-cells. Incretin hormones, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide, also stimulate insulin secretion. However, as obesity and type 2 diabetes worsen, glucose-dependent insulinotropic polypeptide loses its insulinotropic efficacy, whereas GLP-1 receptor (GLP-1R) agonists continue to be effective owing to its signaling switch from Gs to Gq. Herein, we demonstrated that endoplasmic reticulum (ER) stress induced a transition from Gs to Gq in GLP-1R signaling in mouse islets. Intriguingly, chemical chaperones known to alleviate ER stress, such as 4-PBA and TUDCA, enforced GLP-1R's Gq utilization rather than reversing GLP-1R's signaling switch induced by ER stress or obese and diabetic conditions. In addition, the activation of X-box binding protein 1 (XBP1) or activating transcription factor 6 (ATF6), 2 key ER stress-associated signaling (unfolded protein response) factors, promoted Gs utilization in GLP-1R signaling, whereas Gq employment by ER stress was unaffected by XBP1 or ATF6 activation. Our study revealed that ER stress and its associated signaling events alter GLP-1R's signaling, which can be used in type 2 diabetes treatment.

Contemporary Management of Cardiac Implantable Electronic Device Infection: The American College of Cardiology COGNITO Survey.

Background: Cardiac implantable electronic devices (CIEDs) infection remains a serious complication, causing increased morbidity and mortality. Early recognition and escalation to definitive therapy including extraction of the infected device often pose challenges. Objectives: The purpose of this study was to assess U.S.-based physicians current practices in diagnosing and managing CIED infections and explore potential extraction barriers. Methods: An observational survey was performed by the American College of Cardiology including U.S. physicians managing CIEDs from February to March 2022. Sampling techniques and screener questions determined eligibility. The survey featured questions on knowledge and experience with CIED infection patients and case scenarios. Results: Of 387 physicians completing the survey (20% response rate), 49% indicated familiarity with current guidelines regarding CIED infection. Electrophysiologists (EPs) (91%) were more familiar with these guidelines, compared to non-EP cardiologists (29%) and primary care physicians (23%). Only 30% of physicians specified that their institution had guideline-based protocols in place for managing patients with CIED infection. When presented with pocket infection cases, approximately 89% of EPs and 50% of non-EP cardiologists would follow guideline recommendation to do complete CIED system removal, while 70% of primary care physicians did not recommend guideline-directed treatment. Conclusions: There are gaps in familiarity of guidelines as well as the knowledge in practical management of CIED infection with non-extracting physicians. Most institutions lack a definite pathway. Addressing discrepancies, including guideline education and streamlining care or referral pathways, will be a key factor to bridging the gap and improving CIED infection patient outcomes.

A novel magnetic graphene-loaded biochar gel for the remediation of arsenic- and antimony-contaminated mining soil.

Metalloid co-contamination such as arsenic (As) and antimony (Sb) in soils has posed a significant threat to ecological balance and human well-being. In this study, a novel magnetic graphene-loaded biochar gel (FeBG) was developed, and its remediation potential for the reclamation of AsSb spoiled soil was assessed through a six-month soil incubation experiment. Results showed that the incorporation of iron substances and graphene imparted FeBG with enhanced surface characteristics, such as the formation of a new FeO bond and an enlarged surface area compared to the pristine biochar (BC) (80.5 m2 g-1 vs 57.4 m2 g-1). Application of FeBG significantly decreased Na2HPO4-extractable concentration of As in soils by 9.9 %, whilst BC addition had a non-significant influence on As availability, compared to the control. Additionally, both BC (8.2 %) and FeBG (16.4 %) treatments decreased the Na2HPO4-extractable concentration of Sb in soils. The enhanced immobilization efficiency of FeBG for As/Sb could be attributed to FeBG-induced electrostatic attraction, complexation (Fe-O(H)-As/Sb), and π-π electron donor-acceptor coordination mechanisms. Additionally, the FeBG application boosted the activities of sucrase (9.6 %) and leucine aminopeptidase (7.7 %), compared to the control. PLS-PM analysis revealed a significant negative impact of soil physicochemical properties on the availability of As (ß = -0.611, P < 0.01) and Sb (ß = -0.848, P < 0.001) in soils, in which Sb availability subsequently led to a suppression in soil enzyme activities (ß = -0.514, P < 0.01). Overall, the novel FeBG could be a potential amendment for the simultaneous stabilization of As/Sb and the improvement of soil quality in contaminated soils.

Pristine and Fe-functionalized biochar for the simultaneous immobilization of arsenic and antimony in a contaminated mining soil.

This study examined the effectiveness of pristine biochar (BC) and Fe-functionalized biochar (FBC) in remediating As-Sb co-contaminated soil, and revealed the resulting impact on soil enzymatic activities and bacterial communities. Results from incubation experiments showed that the 1.5% FBC treatment reduced the bioavailable As and Sb concentration by 13.5% and 27.1%, respectively, in compared to the control, and reduced the proportion of specifically adsorbed and amorphous Fe-Mn oxide-bound metal(loid) fractions in the treated soil. Among the BC treatments, only the 1.5% BC treatment resulted in a reduction of bioavailable As by 11.7% and Sb by 21.4%. The 0.5% BC treatment showed no significant difference. The FBC achieved high As/Sb immobilization efficiency through Fe-induced electrostatic attraction, π-π electron donor-acceptor coordination, and complexation (Fe-O(H)-As/Sb) mechanisms. Additionally, the 1.5% FBC treatment led to a 108.2% and 367.4% increase in the activities of N-acetyl-ß-glucosaminidase and urease in soils, respectively, compared to the control. Furthermore, it significantly increased the abundance of Proteobacteria (15.2%), Actinobacteriota (37.0%), Chloroflexi (21.4%), and Gemmatimonadota (43.6%) at the phylum level. Co-occurrence network analysis showed that FBC was better than BC in increasing the complexity of bacterial communities. Partial least squares path modeling further indicated that the addition of biochar treatments can affect soil enzyme activities by altering soil bacterial composition. This study suggests that FBC application offers advantages in simultaneous As and Sb immobilization and restructuring the bacterial community composition in metal(loid)-contaminated soil.

Large-flake graphene-modified biochar for the removal of bisphenol S from water: rapid oxygen escape mechanism for synthesis and improved adsorption performance.

The combined effects of graphene and biochar for enhanced adsorption of organic pollutants have not been demonstrated yet. Therefore, the mechanisms of graphene-modified biochar synthesis and its application to adsorption of contaminants remain unclear. In this study, the effect of flake-size graphene on biochar modification and its bisphenol S (BPS) adsorption performance was explored for the first time. Three sizes of graphene oxide were used as the precursor to prepare graphene/biochar composites using pyrolysis. It was found that the graphene with a small flake size was interspersed in the macropores of biochar, while the biochar was completely or mostly wrapped by the large-sized graphene sheet, which effectively prevented the agglomeration and pore blockage of biochar. Large-flake graphene oxide modified biochar (LGB) showed the highest adsorption capacity towards BPS, exhibiting 2.8 times higher adsorption than pristine biochar. Density functional theory (DFT) calculation suggested that the maximum diffusion barrier of O atoms in graphene coated cellulose (most frequently used biochar representative) could be reduced significantly (∼46%) at pyrolysis temperature of 873 K. Taking the advantage of small amount of graphene and enhanced adsorption performance, LGB could be a promising adsorbent for the removal of certain organic pollutants from wastewater and is conducive for the development of high-valued biochar modification.

Chitin and crawfish shell biochar composite decreased heavy metal bioavailability and shifted rhizosphere bacterial community in an arsenic/lead co-contaminated soil.

Sustainable management of ever-increasing organic biowaste and arable soil contamination by potentially toxic elements are of concern from both environmental and agricultural perspectives. To tackle the waste issue of crawfish shells and simultaneously minimize the threat of arsenic (As) and lead (Pb) to human health, a pot trial was conducted using chitin (CT), crawfish shell biochar (CSB), crawfish shell powder (CSP), and CT-CSB composite to compare their remediation efficiencies in As/Pb co-contaminated soil. Results demonstrated that addition of all amendments decreased Pb bioavailability, with the greatest effect observed for the CT-CSB treatment. Application of CSP and CSB increased the soil available As concentration, while significant decreases were observed in the CT and CT-CSB treatments. Meanwhile, CT addition was the most effective in enhancing the soil enzyme activities including acid phosphatase, α-glucosidase, N-acetyl-ß-glucosaminidase, and cellobiohydrolase, whereas CSB-containing treatments suppressed the activities of most enzymes. The amendments altered the bacterial abundance and composition in soil. For instance, compared to the control, all treatments increased Chitinophagaceae abundance by 2.6-4.7%. The relative abundance of Comamonadaceae decreased by 1.6% in the CSB treatment, while 2.1% increase of Comamonadaceae was noted in the CT-CSB treatment. Redundancy and correlation analyses (at the family level) indicated that the changes in bacterial community structure were linked to bulk density, water content, and As/Pb availability of soils. Partial least squares path modeling further indicated that soil chemical property (i.e., pH, dissolved organic carbon, and cation exchange capacity) was the strongest predictor of As/Pb availability in soils following amendment application. Overall, CT-CSB could be a potentially effective amendment for simultaneously immobilizing As and Pb and restoring soil ecological functions in contaminated arable soils.