Breath volatile organic compounds for chronic kidney disease progression monitoring.

Breath analysis may provide a convenient and non-invasive method for clinical monitoring of chronic kidney disease (CKD) progression. However, few breath volatile organic compounds (VOCs) indicating progression of CKD have been reported. In this study, we used gas chromatography-mass spectrometry (GC-MS) for untargeted detection of breath VOCs in stage 1, 3, and 5 CKD patients. The results showed that, the levels of breath 4-heptanone, n-octane, and n-dodecane gradually increased from CKD stage 1 to stage 5, and their increasing rates from CKD stage 3 to stage 5 were higher than those from CKD stage 1 to stage 3. Gender, smoking habits, age, and body mass index (BMI) had insignificant impact on the levels of the three breath VOCs. The accuracies of the polynomial support vector machine (SVM) and K-nearest neighbour (KNN) models based on 4-heptanone + n-octane + n-dodecane combination in distinguishing CKD stages 1, 3, and 5 were 76.3% and 72.8%, respectively. The combination of 4-heptanone + n-octane + n-dodecane was superior to any single component for monitoring CKD progression. These discoveries have valuable implications for long-term clinical monitoring of CKD and improving our understanding of CKD.

The direct binding of bioactive peptide Andersonin-W1 to TLR4 expedites the healing of diabetic skin wounds.

BACKGROUND: Chronic nonhealing wounds remain a considerable challenge in clinical treatment due to excessive inflammation and impeded reepithelialization and angiogenesis. Therefore, the discovery of novel prohealing agents for chronic skin wounds are urgent and important. Amphibian-derived prohealing peptides, especially immunomodulatory peptides, provide a promising strategy for the treatment of chronic skin trauma. However, the mechanism of immunomodulatory peptides accelerating the skin wound healing remains poorly understood. METHODS: The prohealing ability of peptide Andersonin-W1 (AW1) was assessed by cell scratch, cell proliferation, transwell, and tube formation. Next, full-thickness, deep second-degree burns and diabetic full-thickness skin wounds in mice were performed to detect the therapeutic effects of AW1. Moreover, the tissue regeneration and expression of inflammatory cytokines were evaluated by hematoxylin and eosin (H&E), enzyme-linked immunosorbent assay (ELISA), and immunohistochemistry staining. Molecular docking, colocalization, and western blotting were used to explore the mechanism of AW1 in promoting wound healing. RESULTS: We provide solid evidence to display excellent prohealing effects of AW1, identified as a short antimicrobial peptide in our previous report. At relative low concentration of nM, AW1 promoted the proliferation, migration, and scratch repair of keratinocyte, macrophage proliferation, and tube formation of HUVEC. AW1 also facilitated reepithelialization, granulation regeneration, and angiogenesis, thus significantly boosting the healing of full-thickness, deep second-degree burns and diabetic skin wounds in mice. Mechanistically, in macrophages, AW1 directly bound to Toll-like receptor 4 (TLR4) in the extracellular region and regulated the downstream nuclear factor-κB (NF-κB) signaling pathway to facilitate the inflammatory factor secretion and suppress excessive inflammation induced by lipopolysaccharide (LPS). Moreover, AW1 regulated macrophage polarization to promote the transition from the inflammatory to the proliferative phase and then facilitated reepithelialization, granulation regeneration, and angiogenesis, thus exhibiting excellent therapeutic effects on diabetic skin wounds. CONCLUSIONS: AW1 modulates inflammation and the wound healing process by the TLR4/NF-κB molecular axis, thus facilitating reepithelialization, granulation regeneration, and angiogenesis. These findings not only provided a promising multifunctional prohealing drug candidate for chronic nonhealing skin wounds but also highlighted the unique roles of "small" peptides in the elucidation of "big" human disease mechanisms.

Pencil-on-Paper Humidity Sensor Treated with NaCl Solution for Health Monitoring and Skin Characterization.

Although flexible humidity sensors are essential for human health monitoring, it is still challenging to achieve high sensitivity and easy disposal with simple, low-cost fabrication processes. This study presents the design and fabrication of highly reliable hand-drawn interdigital electrodes from pencil-on-paper treated with NaCl solution for highly sensitive hydration sensors working over a wide range of relative humidity (RH) levels from 5.6% to 90%. The applications of the resulting flexible humidity sensor go beyond the monitoring of respiratory rate and proximity to characterizations of human skin types and evaluations of skin barrier functions through insensible sweat measurements. The sensor array can also be integrated with a diaper to result in smart diapers to alert for an early diaper change. The design and fabrication strategies presented in this work could also be leveraged for the development of wearable, self-powered, and recyclable sensors and actuators in the future.

Prediction of Human Pharmacokinetics of E0703, a Novel Radioprotective Agent, Using Physiologically Based Pharmacokinetic Modeling and an Interspecies Extrapolation Approach.

E0703, a new steroidal compound optimized from estradiol, significantly increased cell proliferation and the survival rate of KM mice and beagles after ionizing radiation. In this study, we characterize its preclinical pharmacokinetics (PK) and predict its human PK using a physiologically based pharmacokinetic (PBPK) model. The preclinical PK of E0703 was studied in mice and Rhesus monkeys. Asian human clearance (CL) values for E0703 were predicted from various allometric methods. The human PK profiles of E0703 (30 mg) were predicted by the PBPK model in Gastro Plus software 9.8 (SimulationsPlus, Lancaster, CA, USA). Furthermore, tissue distribution and the human PK profiles of different administration dosages and forms were predicted. The 0.002 L/h of CL and 0.005 L of Vss in mice were calculated and optimized from observed PK data. The plasma exposure of E0703 was availably predicted by the CL using the simple allometry (SA) method. The plasma concentration-time profiles of other dosages (20 and 40 mg) and two oral administrations (30 mg) were well-fitted to the observed values. In addition, the PK profile of target organs for E0703 exhibited a higher peak concentration (Cmax) and AUC than plasma. The developed E0703-PBPK model, which is precisely applicable to multiple species, benefits from further clinical development to predict PK in humans.

Adaptive immune dysfunction in patients with COVID-19 and impaired kidney function during the omicron surge.

BACKGROUND: Little is known about the characteristics of lymphocyte subsets and the association with patient outcomes in COVID-19 with and without impaired kidney function. METHODS: Lymphocyte subsets were compared in COVID-19 patients with or without kidney dysfunction. The primary outcome was a composite of all-cause mortality or intensive care unit admission. Secondary outcomes included duration of viral shedding, length of hospital stay, and acute kidney injury. RESULTS: Lymphocyte subset cell counts demonstrated the lowest in patients with severe/critical COVID-19 and kidney dysfunction. Among all lymphocyte subset parameters, Th cell count was the most significant indicator for outcomes. ROC of the combined model of Th cell count and eGFR presented better predictive value than that of the other parameters. Th cell count <394.5 cells/µl and eGFR <87.5 ml/min/1·73m2 were independently associated with poor outcomes. The propensity score matching analysis revealed consistent results. CONCLUSIONS: Reduced Th cell count and eGFR may be applied as promising predictive indicators for identifying COVID-19 patients with high risk and poor outcomes.

Superhydrophobic, stretchable kirigami pencil-on-paper multifunctional device platform.

Wearable electronics with applications in healthcare, human-machine interfaces, and robotics often explore complex manufacturing procedures and are not disposable. Although the use of conductive pencil patterns on cellulose paper provides inexpensive, disposable sensors, they have limited stretchability and are easily affected by variations in the ambient environment. This work presents the combination of pencil-on-paper with the hydrophobic fumed SiO2 (Hf-SiO2) coating and stretchable kirigami structures from laser cutting to prepare a superhydrophobic, stretchable pencil-on-paper multifunctional sensing platform. The resulting sensor exhibits a large response to NO2 gas at elevated temperature from self-heating, which is minimally affected by the variations in the ambient temperature and relative humidity, as well as mechanical deformations such as bending and stretching states. The integrated temperature sensor and electrodes with the sensing platform can accurately detect temperature and electrophysiological signals to alert for adverse thermal effects and cardiopulmonary diseases. The thermal therapy and electrical stimulation provided by the platform can also deliver effective means to battle against inflammation/infection and treat chronic wounds. The superhydrophobic pencil-onpaper multifunctional device platform provides a low-cost, disposable solution to disease diagnostic confirmation and early treatment for personal and population health.

Shear wave elastography parameters adds prognostic value to adverse outcome in kidney transplantation recipients.

INTRODUCTION: The tissue stiffness of donor kidneys in transplantation may increase due to pathological changes such as glomerulosclerosis and interstitial fibrosis, and those changes associate worse outcomes in kidney transplantation recipients. Ultrasound elastography is a noninvasive imaging examination with the ability to quantitatively reflect tissue stiffness. Aim of this study was to evaluate the prognostic value of ultrasound elastography for adverse kidney outcome in kidney transplantation recipients. METHODS: Shear wave elastography (SWE) examinations were performed by two independent operators in kidney transplantation recipients. The primary outcome was a composite of kidney graft deterioration, all-cause re-hospitalization, and all-cause mortality. Survival analysis was calculated by Kaplan-Meier curves with the log-rank test and Cox regression analysis. RESULTS: A total of 161 patients (mean age 46 years, 63.4% men) were followed for a median of 20.1 months. 27 patients (16.77%) reached the primary endpoint. The mean and median tissue stiffness at the medulla (hazard ratio: 1.265 and 1.229, respectively), estimated glomerular filtration rate (eGFR), and serum albumin level were associated with the primary outcome in univariate Cox regression. Adding mean or median medulla SWE to a baseline model containing eGFR and albumin significantly improved its discrimination (C-statistics: 0.736 for the baseline, 0.766 and 0.772 for the model added mean and median medulla SWE, respectively). CONCLUSION: The medullary tissue stiffness of kidney allograft measured by shear wave elastography may provide incremental prognostic value to adverse outcomes in kidney transplantation recipients. Including SWE parameters in kidney transplantation recipients management could be considered to improve risk stratification.

GaitSG: Gait Recognition with SMPLs in Graph Structure.

Gait recognition aims to identify a person based on his unique walking pattern. Compared with silhouettes and skeletons, skinned multi-person linear (SMPL) models can simultaneously provide human pose and shape information and are robust to viewpoint and clothing variances. However, previous approaches have only considered SMPL parameters as a whole and are yet to explore their potential for gait recognition thoroughly. To address this problem, we concentrate on SMPL representations and propose a novel SMPL-based method named GaitSG for gait recognition, which takes SMPL parameters in the graph structure as input. Specifically, we represent the SMPL model as graph nodes and employ graph convolution techniques to effectively model the human model topology and generate discriminative gait features. Further, we utilize prior knowledge of the human body and elaborately design a novel part graph pooling block, PGPB, to encode viewpoint information explicitly. The PGPB also alleviates the physical distance-unaware limitation of the graph structure. Comprehensive experiments on public gait recognition datasets, Gait3D and CASIA-B, demonstrate that GaitSG can achieve better performance and faster convergence than existing model-based approaches. Specifically, compared with the baseline SMPLGait (3D only), our model achieves approximately twice the Rank-1 accuracy and requires three times fewer training iterations on Gait3D.

High expression of diffuse panbronchiolitis critical region 1 gene promotes cell proliferation, migration and invasion in pancreatic ductal adenocarcinoma.

Diffuse panbronchiolitis critical region 1 (DPCR1) is located in the major histocompatibility complex (MHC) class I. It was reported to be downregulated in invasive pituitary adenoma compared with that in non-invasive tumors, but upregulated in the precursor of gastric carcinogenesis. However, the direct effect of DPCR1 on cancer cells has rarely been reported, and the role DPCR1 in pancreatic ductal adenocarcinoma (PDAC) remains unclear. The clinical sample validation and public data analysis of the present study demonstrated that DPCR1 was upregulated markedly in PDAC and this high expression was negatively correlated with the patient prognosis. Functionally, knocking down DPCR1 in PDAC cell lines inhibited cell proliferation, migration and invasion in vitro. Tumor xenograft experiments further showed that suppression of DPCR1 inhibited tumor growth in vivo. In addition, the results of RNA deep sequencing and qRT-PCR assay showed that DPCR1 participated in PADC progression by regulating nuclear factor-kappa B signaling pathway, suggesting that it might be a novel oncogene in tumor progression and a potential therapeutic target in PDAC as well.

Evaluation of Clinical Plus Imaging Features and Multidetector Computed Tomography Texture Analysis in Preoperative Risk Grade Prediction of Small Bowel Gastrointestinal Stromal Tumors.

OBJECTIVE: This study aimed to evaluate the prediction roles of clinical plus imaging features and multidetector computed tomography (MDCT) texture analysis in preoperative risk grade classification of small bowel (SB) gastrointestinal stromal tumors (GISTs). METHODS: This study included 213 SB GIST patients. Clinical features and MDCT imaging findings were reviewed. Tumor risk stratifications were determined according to modified National Institutes of Health criteria. Random forest models were performed to evaluate the correlation of risk stratification. RESULTS: The model of clinical plus imaging findings showed an area under receiver operating characteristic curve (AUC) of 92.0%. The AUC of texture analysis based on MDCT portal phase was 93.3%, without statistical difference from that of clinical plus imaging model (P = 0.378). The AUC of the model combined clinical plus imaging features and MDCT texture analysis was 94.3%, which was significantly higher than the AUC of clinical imaging model (P = 0.042). CONCLUSION: Texture analysis may become an important comprehensive tool for preoperative risk stratification of SB GISTs.

Effects of pretransplant peritoneal vs hemodialysis modality on outcome of first kidney transplantation from donors after cardiac death.

BACKGROUND: The effect of pretransplant peritoneal dialysis (PD) or hemodialysis (HD) modality on outcomes of kidney transplantation (KT) for end-stage renal disease (ESRD) is debatable. We evaluated the outcomes these modalities in KT from donor after cardiac death (DCD). METHODS: A cohort of 251 patients on HD, PD or pre-emptive who underwent first KT from DCD between January 2014 and December 2016 were prospectively analyzed to compare for outcomes on recovery of renal function, complications as well as patient and graft survival. The patients were followed till August 2017. Data on 104 HD and 98 PD were available for final comparative outcome analysis, 5 pre-emptive were analyzed as the control group. RESULTS: Both HD and PD group patients were well matched for demographic and baseline characteristics. The follow-up period was 12.5 (3.0, 22.0) months in HD and 12.0 (6.0, 20.0) months in PD patients. Post-transplant renal functions between the two groups showed no differences. Among PD patients, 16 (16.3%) suffered delayed graft function, versus 19 (18.3%) in HD, with no statistical differences (p = 0.715). Complications of acute rejection, infections were comparable between the groups. The patient survival, graft survival and death-censored graft survival were similar for HD and PD after adjusting for other multiple risk factors. CONCLUSIONS: Our results indicate that outcome of first KT from DCD is not affected by pretransplant dialysis modality of PD or HD in aspects of recovery of renal function, complications as well as patient and graft survival.

A case of ureteral myeloid sarcoma post-renal transplantation.

BACKGROUND: Significant attention has been directed toward the high incidence of malignant tumours that occur post-transplantation. However, there are few reports of myeloid sarcomas (MSs) following renal transplantation. CASE PRESENTATION: This case report describes a 26-year-old male patient who presented with repeatedly high creatinine levels and hydronephrosis six months post-renal transplantation. Surgical pathology revealed ureteral MS; however, the tumour recurred following resection. Bone marrow biopsy indicated that the patient also had acute promyelocytic leukaemia. The tumour was treated with local radiotherapy, and the leukaemia was treated with systemic chemotherapy. The patient's conditions were satisfactory at the one-year follow-up. CONCLUSIONS: This report is the first to describe a ureteral MS post-renal transplantation. Our findings suggest that surgical resection combined with radiotherapy and chemotherapy can help control the status of patients with this condition.

[Effects of cerium oxide nanoparticles on cognitive function in 48 h sleep deprived male mice].

OBJECTIVE: To study the effects of cerium oxide nanoparticles( CeO_2 NPs)on cognitive function in 48 hours of sleep deprived male mice and explore its mechanism. METHODS: Thirty-six healthy clean ICR male mice( four weeks old) were randomly divided into 6 groups: blank control group, solvent control group, sleep deprivation control group, low, medium and high dose groups of CeO_2 NPs. 1 m L of distilled water were given to mice of blank group, 1 m L of solvent were given to mice of solvent control and sleep deprivation control group, 1 mL of CeO_2 NPs solvent( 4, 8, 16 mg/kg) were administered to mice of low, medium and high dose groups of CeO_2 NPs. Each group of mice received intragastric administration for 30 days. On the 31 st day, a single platform water environment method was used for 48 hours of sleep deprivation on mice. Then, the cognitive ability of the mice was tested by Y-maze. Further, the antioxidant( CAT, MDA, T-AOC) and neurotransmitters( NO, Glu) in mice brain tissue were measured also. RESULTS: Compare with the solvent control group, 48 hours of sleep deprivation reduced the cognitive ability of mice [( 36 ± 2) times vs. ( 20 ± 2) times, P = 0. 0006; 10. 753%± 0. 031% vs. 24. 927% ± 0. 972%, P = 0. 00000045 ], CAT activity [( 78. 151 ±17. 683) nmol/mg prot vs. ( 198. 155 ± 14. 437) nmol/mg prot, P = 0. 0008]and the level of T-AOC [( 103. 630 ± 24. 209) U/mg prot vs. ( 264. 599 ± 50. 223) U/mg prot, P =0. 007], but improved the content of MDA [( 9. 499 ± 1. 249) nmol/mg prot vs. ( 6. 157± 0. 373) nmol/mg prot, P = 0. 0113 ], NO [( 11. 608 ± 1. 281) µmol/mg prot vs. ( 3. 628 ± 1. 064) µmol/mg prot, P = 0. 001]and Glu[( 4. 731 ± 0. 131) µg/mg prot vs. ( 4. 476 ± 0. 126) µg/mg prot, P = 0. 03] in the brain. Low, medium and high dose Ce O2 NPs enhanced cognitive performance of the sleep deprived mice. Among three dose groups, the medium dose groups most significantly improved the cognitive ability of mice[( 27 ± 2) times vs. ( 36 ± 2) times, P = 0. 005; 18. 743% ± 0. 245% vs. 10. 753% ±0. 031%, P = 0. 0000006 ], increased CAT activities [( 238. 065 ± 19. 393) nmol/mg prot vs. ( 78. 151 ± 17. 683) nmol/mg prot, P = 0. 00045] and T-AOC levels [( 210. 516± 11. 339) U/mg prot vs. ( 103. 630 ± 24. 209) U/mg prot, P = 0. 002], decreased MDA[( 6. 528 ± 1. 162) nmol/mg prot vs. ( 9. 499 ± 1. 249) nmol/mg prot, P = 0. 039], NO[( 5. 651 ± 0. 239) µmol/mg prot vs. ( 11. 608 ± 1. 281) µmol/mg prot, P = 0. 001]and Glu levels [( 4. 358 ± 0. 016) µg/mg prot vs. ( 4. 731 ± 0. 131) µg/mg prot, P = 0. 008]. CONCLUSION: Ce O2 NPs can improve the cognitive ability of sleep deprived male mice, improve the antioxidant capacity of brain, reduce free radical damage to the nerves of brain, and regulate the neurotransmitters of brain.

Analysis on therapeutic outcomes and prognostic factors of intracranial ependymoma: a report of 49 clinical cases in a single center.

Although intracranial ependymoma is relatively rare, it is often associated with great clinical aggressiveness and poor overall survival. There are controversies over factors affecting the prognosis of the disease. The aim of this retrospective study was to evaluate factors that may affect the therapeutic outcome and prognosis of intracranial ependymoma by reviewing the medical records of 49 patients who were surgically treated in our hospital between 2001 and 2014. Univariate and multivariate analyses were performed to identify prognostic variables relative to patient and tumor characteristics, and treatment modalities. All 49 patients (24 men and 25 women; mean age 27.6 years) underwent surgical resection, of whom 14 patients also underwent postoperative radiotherapy. Local recurrence was found in 15 (48.8 %) patients, and 22 (51.2 %) patients died during the follow-up periods. The 5-year recurrence rate was 65 % and the survival rate was 51 %. The results of statistical analysis suggested that preoperative extraventricular drainage and surgical resection extent were prognostic factors related to progression-free survival, and that age, surgical resection extent and histological grade were closely associated with survival. Interestingly, there was a significant correlation between the symptom of hydrocephalus and age (P = 0.010), and patients with a better clinical status (KPS ≥ 80) were significantly associated with a lower WHO grade (P = 0.007). In conclusion, we confirmed that surgical resection extent was the major independent factor affecting both recurrence and survival of patients with intracranial ependymoma, while age and WHO grade were prognostic factors affecting survival but not recurrence.

An efficient rare-earth free deep red-emitting GdGeSbO6:Mn4+ phosphor for white light-emitting diodes.

Red phosphors play an important role in improving the light quality and color rendering index of white light-emitting diodes (WLEDs) for lighting. In this paper, we report the transition ion Mn4+-activated deep red phosphor GdGeSbO6:x%Mn4+ and analyze its crystal structure, composition and luminescence behavior in detail. Its optimal doping concentration of Mn4+ is 0.3%. Under ultraviolet (UV) excitation, GdGeSbO6:0.3%Mn4+ produces a narrow emission peak centred at 682 nm in the range of 650-800 nm with a full width at half maximum (FWHM) of 25 nm, which is attributed to the spin-prohibited 2Eg → 4A2g transition of Mn4+ ions. Notably, the optimal phosphor GdGeSbO6:0.3%Mn4+ has a high internal quantum efficiency (IQE ≈ 65%) and excellent thermal stability performance (I423 K/I303 K ≈ 62%). The synthesis of high-performance warm WLEDs and full-spectrum WLEDs was achieved by combining and coating GdGeSbO6:0.3%Mn4+ phosphors with commercial phosphors on the surface of a 365 nm UV chip.

Protective effect of chicken yolk antibody Y against Campylobacter jejuni induced diarrhea in cats.

Campylobacter jejuni (C. jejuni) is a common pathogen that often causes diarrhea, loss of appetite, and even enteritis in domestic cats, affecting their growth and development, especially in kittens under 6 months of age. Oral passive immunization with chicken yolk antibody Y has been proved effective for the treatment of gastrointestinal pathogen infections due to its high specificity. In this study, C. jejuni was isolated from diarrheal cat feces, and the specific egg yolk antibody Y against C. jejuni was demonstrated to effectively inhibit its proliferation in vitro experiments. To evaluate the effect of anti-C. jejuni IgY, the mouse C. jejuni infection model was established and it was found that IgY could alleviate C. jejuni-induced clinical symptoms. Consistent with these results, the reduction of pro-inflammatory factors and intestinal colonization by C. jejuni in the IgY-treated groups, especially in the high dose group. We then evaluated the protective effect of IgY on young Ragdoll cats infected with C. jejuni. This specific antibody reduced the rate of feline diarrhea, protected the growth of young cats, inhibited systemic inflammatory hyperactivation, and increased fecal short-chain fatty acid concentrations. Notably, IgY may have a protective role by changing intestinal amino acid metabolism and affecting C. jejuni chemotaxis. Collectively, specific IgY is a promising therapeutic strategy for C. jejuni-induced cat diarrhea.

Additive renal protective effects between arctigenin and puerarin in diabetic kidney disease.

Recent studies have shown that the combined use of renin angiotensin system inhibitor, SGLT2 inhibitors and/or mineralocorticoid receptor antagonist provides additional renal protection for patients with diabetic kidney disease (DKD). Similarly, in traditional Chinese medicine, the synergistic application of multiple herbs often brings more significant therapeutic effects. However, the synergistic or additive mechanisms of traditional Chinese medicine in combination therapy are not fully understood. In our previous studies, we show that arctigenin (ATG), a major component of Fructus Arctii, attenuates proteinuria and renal injury in diabetic mice by activating PP2A, and puerarin (a class of known isoflavones) can also reduce proteinuria and renal injury in diabetic mice via activation of Sirt1. Here, we further explored the potential additive renal protection of these two compounds in diabetic mice. Research has found that ATG and puerarin have a synergistic effect in reducing albuminuria in db/db mice. Mechanistically, we found that ATG reduced NF-κB p65 phosphorylation likely through activation of PP2A while puerarin reduced p65 acetylation via Sirt1 activation. Therefore, ATG and puerarin have additive inhibitory effects on the NF-κB activation, which is a key inflammatory pathway in DKD. RNA-sequencing analysis revealed distinct pathways activated by ATG and puerarin in the diabetic kidney, which may provide an additional mechanism for their additive effects in DKD. Our study suggests that ATG and puerarin could be a new combination therapy for DKD and reveals its underlined mechanisms.

Dissolved organic matter influences the indigenous bacterial community and polycyclic aromatic hydrocarbons biodegradation in soils.

In polycyclic aromatic hydrocarbon (PAH) contaminated soils, bioremediation is superior to other strategies owing to its low cost and environmental friendliness. However, dissolved organic matter (DOM) and indigenous bacterial communities can affect the efficiency of PAH-degrading bacteria (PDB). This study found that exogenous PDB (C1) including the genera Acinetobacter, Stenotrophomonas, and Comamonas, decreased the bacterial diversity of Alfisol, Ultisol, Inceptisol, and Mollisol, and DOM enhanced the diffusion of PDB and the bioavailability of PAH. In addition, bacteria preferred to ingest low molecular weight DOM fractions, and the abundances of lipid-like and protein-like substances decreased by 0.12-3.03 % and 1.73-4.60 %. The DOM fractions had a more marked influence on the indigenous bacteria than the exogenous PDB, and PDB dominated the PAH biodegradation process in the soils. More COO functional groups promoted the utilization of higher molecular weight-related homologue fractions by bacteria, and lower molecular weight fractions carrying more CH2 functional groups declined during biodegradation. This study investigated the variations in bacterial communities during biodegradation and revealed the effects of DOM fractions on biodegradation in PAH-contaminated soils at the molecular level. These results will promote the development of bioremediation strategies for organics-contaminated soil and provide guidance for prediction models of soil biodegradation kinetics.

Deuteration-Induced Energy Level Structure Reconstruction of Carbon Dots for Enhancing Photoluminescence.

Constrained by a limited understanding of the structure and luminescence mechanisms of carbon dots (CDs), achieving precise enhancement of their photoluminescence (PL) performance without altering the emission wavelength and color remains a challenge. In this work, a deuterated CD is first achieved by simply replacing the reaction solvent from H2O to D2O. The substitution of D atoms for H atoms is not limited on the surface but also within the internal structure of CDs. Deuteration affects the formation of the π-conjugated network structure by altering the content of sp2 carbon and sp3 carbon, ultimately inducing a reconstruction for energy level structure of CDs. Both the intrinsic state and surface state emission, including quantum yield, emission intensity and lifetime, are significantly enhanced after deuteration. It benefits from the reduction in non-radiative transitions, since the lowered vibrational frequencies of D atoms and optimized local energy level distribution in CDs structure. The deuterated CDs are applied in the fabrication of white-light-emitting diodes to show their application potential. This work provides a highly versatile route for improving and controlling photoluminescence performance of CDs and has opportunities to guide the development of CDs for practical applications.