Removal of Aqueous Uranyl and Arsenate Mixtures after Reaction with Limestone, PO43-, and Ca2.

The co-occurrence of uranyl and arsenate in contaminated water caused by natural processes and mining is a concern for impacted communities, including in Native American lands in the U.S. Southwest. We investigated the simultaneous removal of aqueous uranyl and arsenate after the reaction with limestone and precipitated hydroxyapatite (HAp, Ca10(PO4)6(OH)2). In benchtop experiments with an initial pH of 3.0 and initial concentrations of 1 mM U and As, uranyl and arsenate coprecipitated in the presence of 1 g L-1 limestone. However, related experiments initiated under circumneutral pH conditions showed that uranyl and arsenate remained soluble. Upon addition of 1 mM PO43- and 3 mM Ca2+ in solution (initial concentration of 0.05 mM U and As) resulted in the rapid removal of over 97% of U via Ca-U-P precipitation. In experiments with 2 mM PO43- and 10 mM Ca2+ at pH rising from 7.0 to 11.0, aqueous concentrations of As decreased (between 30 and 98%) circa pH 9. HAp precipitation in solids was confirmed by powder X-ray diffraction and scanning electron microscopy/energy dispersive X-ray. Electron microprobe analysis indicated U was coprecipitated with Ca and P, while As was mainly immobilized through HAp adsorption. The results indicate that natural materials, such as HAp and limestone, can effectively remove uranyl and arsenate mixtures.

Study on the Antioxidant and Anticancer Activities of Sorbus pohuashanensis (Hance) Hedl Flavonoids In Vitro and Its Screen of Small Molecule Active Components.

Firstly, the antioxidant capacity of total flavonoids that was extracted from Sorbus pohuashanensis (Hance) Hedl was determined by ABTS+·radical-scavenging method, and MTT assay was used to mensurate the anti-tumor activity of total flavonoids In Vitro. Subsequently, the extraction conditions of flavonoids were optimized by the response surface methodology, the antioxidant activity was investigated simultaneously. Furthermore, the anti-tumor activity mechanism of flavonoids was simulated by molecular docking software. The antioxidant activity of flavonoids was correlated with the content in the process of optimizing the extraction condition. Moreover, The MTT assay revealed that SPF inhibited the activity of four sorts of cancer cells and positively correlated with the concentration of total flavonoids. And the experimental data demonstrated its anticancer activity was better at high concentrations. Finally, its anti-tumor activity was found that may be related to small molecules from flavonoids bind the apoptotic proteins Caspase-3, Caspase-8, and Caspase-9. The study could provide a theoretical basis for further pharmacodynamic research of Sorbus pohuashanensis (Hance) Hedl flavonoids, and improved a valuable attribute to Sorbus pohuashanensis (Hance) Hedl.

Human attention-inspired volume reconstruction method on serial section electron microscopy images.

The alignment of a 2D microscopic image stack to create a 3D image volume is an indispensable aspect of serial section electron microscopy (EM) technology, which could restore the original 3D integrity of biological tissues destroyed by chemical fixation and physical dissection. However, due to the similar texture intrasection and complex variations intersections of neural images, previous registration methods usually failed to yield reliable correspondences. And this also led to misalignment and impeded restoring the z-axis anatomical continuity of the neuron volume. In this article, inspired by human behaviors in finding correspondences, which use the topological relationship of image contents, we developed a spatial attention-based registration method for serial EM images to improve registration accuracy. Our approach combined the U-Net framework with spatial transformer networks (STN) to regress corresponding transformation maps in an unsupervised training fashion. The spatial attention (SA) module was incorporated into the U-Net architecture to increase the distinctiveness of image features by modeling its topological relationship. Experiments are conducted on both simulated and real data sets (MAS and RegCremi). Quantitative and qualitative comparisons demonstrate that our approach results in state of art accuracy (using the evaluation index of NCC, SSIM, Dice, Landmark error) and providing smooth and reliable transformation with less texture blur and unclear boundary than existing techniques. Our method is able to restore image stacks for visualization and quantitative analysis of EM image sequences.

Graphene oxide conjugated with polymers: a study of culture condition to determine whether a bacterial growth stimulant or an antimicrobial agent?

BACKGROUND: The results showed that the deciding factor is the culture medium in which the bacteria and the graphene oxide (GO) are incubated at the initial manipulation step. These findings allow better use of GO and GO-based materials more and be able to clearly apply them in the field of biomedical nanotechnology. RESULTS: To study the use of GO sheets applied in the field of biomedical nanotechnology, this study determines whether GO-based materials [GO, GO-polyoxyalkyleneamine (POAA), and GO-chitosan] stimulate or inhibit bacterial growth in detail. It is found that it depends on whether the bacteria and GO-based materials are incubated with a nutrient at the initial step. This is a critical factor for the fortune of bacteria. GO stimulates bacterial growth and microbial proliferation for Gram-negative and Gram-positive bacteria and might also provide augmented surface attachment for both types of bacteria. When an external barrier that is composed of GO-based materials forms around the surface of the bacteria, it suppresses nutrients that are essential to microbial growth and simultaneously produces oxidative stress, which causes bacteria to die, regardless of whether they have an outer-membrane-Gram-negative-bacteria or lack an outer-membrane-Gram-positive-bacteria, even for high concentrations of biocompatible GO-POAA. The results also show that these GO-based materials are capable of inducing reactive oxygen species (ROS)-dependent oxidative stress on bacteria. Besides, GO-based materials may act as a biofilm, so it is hypothesized that they suppress the toxicity of low-dose chitosan. CONCLUSION: Graphene oxide is not an antimicrobial material but it is a general growth enhancer that can act as a biofilm to enhance bacterial attachment and proliferation. However, GO-based materials are capable of inducing ROS-dependent oxidative stress on bacteria. The applications of GO-based materials can clearly be used in antimicrobial surface coatings, surface-attached stem cells for orthopedics, antifouling for biocides and microbial fuel cells and microbial electro-synthesis.

Rice bran feruloylated oligosaccharides activate dendritic cells via Toll-like receptor 2 and 4 signaling.

This work presents the effects of feruloylated oligosaccharides (FOs) of rice bran on murine bone marrow-derived dendritic cells (BMDCs) and the potential pathway through which the effects are mediated. We found that FOs induced phenotypic maturation of DCs, as shown by the increased expression of CD40, CD80/CD86 and MHC-I/II molecules. FOs efficiently induced maturation of DCs generated from C3H/HeN or C57BL/6 mice with normal toll-like receptor 4 (TLR-4) or TLR-2 but not DCs from mice with mutated TLR4 or TLR2. The mechanism of action of FOs may be mediated by increased phosphorylation of ERK, p38 and JNK mitogen-activated protein kinase (MAPKs) and increased NF-kB activity, which are important signaling molecules downstream of TLR-4 and TLR-2. These data suggest that FOs induce DCs maturation through TLR-4 and/or TLR-2 and that FOs might have potential efficacy against tumor or virus infection or represent a candidate-adjuvant approach for application in immunotherapy and vaccination.

Degradation of chlorinated solvents with reactive iron minerals in subsurface sediments from redox transition zones.

Reactive iron (Fe) mineral coatings found in subsurface reduction-oxidation transition zones (RTZs) contribute to the attenuation of contaminants. An 18.3-m anoxic core was collected from the site, where constituents of concern (COCs) in groundwater included chlorinated solvents. Reactive Fe mineral coatings were found to be abundant in the RTZs. This research focused on evaluating reaction kinetics with anoxic sediments bearing ferrous mineral nano-coatings spiked with either tetrachloroethylene (PCE), trichloroethylene (TCE), or 1,4-dichlorobenzene (1,4-DCB). Reaction kinetics with RTZ sediments followed pseudo-first-order reactions for the three contaminants with 90% degradation achieved in less than 39 days. The second-order rate constants for the three COCs ranged from 6.20 × 10-4 to 1.73 × 10-3 Lg-1h-1 with pyrite (FeS2), 4.97 × 10-5 to 1.24 × 10-3 Lg-1h-1with mackinawite (FeS), 1.25 × 10-4 to 1.89 × 10-4 Lg-1h-1 with siderite (FeCO3), and 1.79 × 10-4 to 1.10 × 10-3 Lg-1h-1 with magnetite (Fe3O4). For these three chlorinated solvents, the trend for the rate constants followed: Fe(II) sulfide minerals > magnetite > siderite. The high reactivity of Fe mineral coatings is hypothesized to be due to the large surface areas of the nano-mineral coatings. As a result, these surfaces are expected to play an important role in the attenuation of chlorinated solvents in contaminated subsurface environments.

[Hand-assisted laparoscopic surgery in radical resection of rectal cancer].

OBJECTIVE: To investigate the application experience and clinical effects of hand-assisted laparoscopic radical resection for rectal cancer. METHODS: The clinical data of 156 patients with rectal cancer treated with hand-assisted laparoscopic surgery between August 2009 and April 2011 were analyzed retrospectively. RESULTS: The operative procedures of 156 patients were completed successfully and 1 case was converted to laparotomy (0.6%). The mean operation time was (125 ± 35) minutes; the mean intraoperative blood loss was (118 ± 60) ml; the mean time of bowel function recovery was (60 ± 8) hours; the median postoperative hospital stay was (9.5 ± 2.2) days. The mean number of lymph nodes dissection was (14 ± 5). Five patients (3.2%) had postoperative complications. All the patients were followed up. There had been no local recurrence or trocar site implantation metastasis. CONCLUSION: Hand-assisted laparoscopic surgery approach for the curative resection of rectal cancer is safe and effective and has broad prospects in clinical application.

Fertility decline in rural China: a comparative analysis.

Many models have been proposed to explain both the rapidity of China's fertility decline after the 1960s and the differential timing of the decline in different places. In particular, scholars argue over whether deliberate policies of fertility control, institutional changes, or general modernization factors contribute most to changes in fertility behavior. Here the authors adopt an ethnographically grounded behavioral-institutional approach to analyze qualitative and quantitative data from three different rural settings: Xiaoshan County in Zhejiang (East China), Ci County in Hebei, (North China), and Yingde County in Guangdong (South China). The authors show that no one set of factors explain differential timing by a combination of differences in social-cultural environments (e.g. spread of education, reproductive ideologies, and gender relations) and politico-economic conditions (e.g. economic development, birth planning campaigns, and collective systems of labor organization) during the early phases of the fertility decline.

Identifying redox transition zones in the subsurface of a site with historical contamination.

Reactive iron mineral coatings found throughout reduction-oxidation (redox) transition zones play an important role in contaminant transformation processes. This research focuses on demonstrating a process for effectively delineating redox transition zones at a site with historical contamination. An 18.3 meter core was collected, subsampled, and preserved under anoxic conditions to maintain its original redox status. To ensure a high vertical resolution, sampling increments of 5.08 cm in length were analyzed for elemental concentrations with X-ray fluorescence (XRF), sediment pH, sediment oxidation-reduction potential (ORP), total volatile organic carbon (TVOC) concentration in the sample headspace, and abundant bacteria (16S rRNA sequencing). Over the core's length, gradients observed ranged from 3.74 to 8.03 for sediment pH, -141.4 mV to +651.0 mV for sediment ORP, and from below detection to a maximum of 9.6 ppm TVOC concentration (as chlorobenzene) in the headspace. The Fe and S gradients correlated with the presence of Fe and S reducing bacteria. S concentrations peaked in the Upper Zone and Zone 1 where Desulfosporosinus was abundant, suggesting precipitation of iron sulfide minerals. In Zone 2, Fe concentrations decreased where Geobacter was abundant, potentially resulting in Fe reduction, dissolution, and precipitation of minerals with increased solubility compared to the Fe(III) minerals. Using complementary geochemical and microbial data, five redox transition zones were delineated in the core collected. This research demonstrates a systematic approach to characterizing redox transition zones in a contaminated environment.

Roles of reactive iron mineral coatings in natural attenuation in redox transition zones preserved from a site with historical contamination.

In this study, a protocol was developed to identify reduction-oxidation (redox) transition zones in an effort to exploit natural source zone depletion processes. A sediment core with a total length of 18-m was collected from a site with historical contamination that includes chlorinated benzenes where the redox condition was preserved. In the four redox transition zones investigated, reactive iron coatings are characterized with a suite of analyses under anaerobic conditions. To distinguish surface coating mineralogy, X-ray diffraction, X-ray fluorescence, and field-emission scanning electron microscopy with an energy dispersive X-ray analyzer were applied along with a six-step sequential extraction process. The cycling of Fe and S, as an important contribution and indicator of ongoing natural attenuation processes for constituents of concern (COC), was delineated by using data from multiple and complementary analyses for isolating and identifying iron phases. Along with groundwater chemistry, contaminant concentrations, and microbial genera, attenuation of COCs is expected to be active and sustainable in redox transition zones, where there is an abundance of reactive iron mineral coatings cycling through biogeochemical reactions. Reactions in other redox transition zones may be limited where iron mineral coatings are not dominant.

Impacts of cryogenic sampling processes on iron mineral coatings in contaminated sediment.

This study focused on comparing iron mineral coatings found in contaminated sediments from a cryogenic (Cryo Core) core versus an Anaerobic Core (collected under oxygen-free and ambient conditions). After thawing the Cryo Core in an oxygen-free glovebox, a suite of analyses was applied on sediments from both cores: pH, redox potential, X-ray fluorescence (XRF), X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray analyzer (EDX). Among the iron minerals identified, crystalline pyrite was found throughout the Cyro Core sediment samples, which is in contrast to that observed for the Anaerobic Core. Moreover, mackinawite and greigite that were ubiquitous in the Anaerobic Core were not observed in Cryo Core samples. To better understand why the metastable minerals were not present, a freeze/thaw process was simulated on Anaerobic Core samples using a liquid­nitrogen quench with surface coatings characterized by FESEM/EDX. In these quenched samples, mackinawite was no longer observed, and in its place was pyrite. In addition, both greigite and pyrite were found to be unique morphologically after quenching. Dissolution and re-precipitation of iron sulfide coatings during the freeze/thaw process appears to affect the geochemistry of the pore water through two main mechanisms of freeze-concentration and freezing potential.

Combined use of chemotherapeutics and oncolytic adenovirus in treatment of AFP-expressing hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) which is always refractory to most chemotherapeutic agents may result in poor survival of patients with advanced HCC. Oncolytic adenovirus is a new form for cancer gene therapy via its ability to replicate and kill tumor cells in a tumor-specific manner. In order to eradicate tumors effectively, the combination of chemotherapeutic agents and oncolytic adenovirus has been considered. This study aimed to systematically analyze the possibility of synergistic cytotoxicity of oncolytic adenoviruses in combination with chemotherapeutic agents. METHODS: Several types of human HCC cell lines were used to determine the specificity and cytotoxicity of oncolytic adenovirus Ad5-HC and Ad5-AFP (IRES) by measuring cell viability in vitro and antitumor efficiency in vivo. The cytotoxicity of Ad5-HC and Ad5-AFP (IRES) combined with chemotherapeutic agents were also assessed by the methyl thiazolyl tetrazolium assay. RESULTS: Both Ad5-HC and Ad5-AFP (IRES) were significantly cytotoxic to HCC cells with great specificity in vitro and in vivo. The combination of oncolytic adenovirus with 5-FU, doxorubicin, and paclitaxel was synergistically effective for the killing of HCC cells. CONCLUSIONS: These data suggest that oncolytic adenovirus sensitize tumors to chemotherapy and the combination therapy of chemotherapeutic agents and oncolytic adenovirus has an enhanced antitumor effect on HCC cells.

Structure Study of Proton Tautomers Based on Ion Mobility Mass Spectrometry and Ab Initio Molecular Dynamics Calculations / 分析化学

Investigating the structural characteristics of proton tautomers is of great significance for understanding organic reactions and biochemical processes.In this study,a method based on ion mobility mass spectrometry combined with ab initio molecular dynamics calculations was proposed.The structures of proton tautomers were determined by comparing the experimental and theoretical collision-induced dissociation(CID)mass spectrograms of different proton tautomers.Ion mobility mass spectrometry was used to separate proton tautomerism produced during ionization.The CID mass spectra of each isomer could be obtained after mobility separation.The quantum chemical mass spectrometry(QCXMS)program based on ab initio molecular dynamics calculations was used to calculate the fragmentation process and obtain the theoretical CID mass spectra.The results of experiment and calculation showed that this method effectively solved the issue of difficult identification of proton tautomers.This method was also of great significance for the study of ionization mechanism and organic reaction process using mass spectrometry.

Advances in the study of the pathogenesis of squamous cell carcinoma / 中国综合临床

Squamous cell carcinoma, which originates from squamous epithelium or tissue that undergoes squamous epithelial metaplasia, is one of the most common pathological types of solid human carcinoma. Although squamous cell carcinoma can occur in different anatomical locations, its pathogenesis has commonalities and distinctive features. Genetic mutations and abnormal expression of squamous differentiation markers, epigenetic modifications regulating target gene expression, and tumor microenvironment inducing immune escape of cancer cells are all involved in the development of squamous cell carcinoma. At present, great progress has been made in the research on the pathogenesis of squamous cell carcinoma. This article, combined with relevant research in recent years, reviews the pathogenesis of squamous cell carcinoma in terms of genome changes, epigenetic changes, non coding RNA regulation, tumor microenvironment changes and risk factor induction, so as to provide reference for the prevention and treatment of squamous cell carcinoma.

Deepening the Action on Salt Reduction in China-suggestions on strategy and implementation plan / 中华预防医学杂志

Excessive sodium/salt intake is the leading dietary risk factor for the loss of healthy life in the Chinese population. The "Healthy China 2030" Action Plan set the goal of reducing salt intake by 20% by 2030. However, salt intake in China is still at a very high level in the world, with adults reaching 11 g/d, more than twice the recommended limit of 5 g/d. The current policies and action plans of China have targeted catering workers, children, adolescents, and home chefs in salt, oil, and sugar reduction actions. However, there are still obvious deficiencies in the coordinated promotion and implementation. This study, therefore, proposed a set of comprehensive strategies (named CHRPS that is composed of communication and education, salt reduction in home cooking, salt reduction in restaurants, reducing salt content in pre-packaged food, and surveillance and evaluation) and key implementation points for further deepening the salt reduction action in China. These strategies were developed based on the main sources of dietary sodium for Chinese residents, the status of "knowledge, attitude and practice" in salt reduction, evidence of effective intervention measures, existing policies and requirements, and the salt reduction strategies of the World Health Organization and experience from some other countries. As a scientific reference, the CHRPS strategies will help the government and relevant organizations quickly implement salt reduction work and facilitate the earlier realization of China's salt reduction goal.

Aligned Organization of Synapses and Mitochondria in Auditory Hair Cells / 神经科学通报·英文版

Recent studies have revealed great functional and structural heterogeneity in the ribbon-type synapses at the basolateral pole of the isopotential inner hair cell (IHC). This feature is believed to be critical for audition over a wide dynamic range, but whether the spatial gradient of ribbon morphology is fine-tuned in each IHC and how the mitochondrial network is organized to meet local energy demands of synaptic transmission remain unclear. By means of three-dimensional electron microscopy and artificial intelligence-based algorithms, we demonstrated the cell-wide structural quantification of ribbons and mitochondria in mature mid-cochlear IHCs of mice. We found that adjacent IHCs in staggered pairs differ substantially in cell body shape and ribbon morphology gradient as well as mitochondrial organization. Moreover, our analysis argues for a location-specific arrangement of correlated ribbon and mitochondrial function at the basolateral IHC pole.

Influencing factors for hypotension in patients undergoing double plasma molecular adsorption system artificial liver support therapy / 临床肝胆病杂志

Objective To investigate the risk factors for intraoperative hypotension (IOH) in patients undergoing double plasma molecular adsorption system (DPMAS) artificial liver support therapy. Methods Clinical data were collected from 181 patients (670 cases in total) who underwent DPMAS artificial liver support therapy in Liver Disease Center of The First Affiliated Hospital of University of Science and Technology of China from October 1, 2017 to December 31, 2020, and according to the presence or absence of IOH during DPMAS therapy, they were divided into IOH group with 70 patients and non-IOH group with 111 patients.Clinical indicators were compared between the two groups and their association with IOH was analyzed; prognosis was analyzed at 12 and 24 weeks.The independent samples t -test was used for comparison of normally distributed continuous data between groups, and the Mann-Whitney U test was used for comparison of non-normally distributed continuous data between groups; the chi-square test was used for comparison of categorical data between groups.Univariate and multivariate Logistic regression analyses were used to investigate the risk factors for IOH.The Kaplan-Meier method was used to plot receiver operating characteristic (ROC) curves, and the Z test was used for comparison of the area under the ROC curve (AUC) of independent risk factors. Results The univariate Logistic regression analysis showed that female individuals, individuals aged ≥50 years, and individuals with normal or low body mass index (BMI) tended to have a higher risk of IOH (all P < 0.05), and the multivariate analysis showed that normal or low BMI (odds ratio [ OR ]=3.290, 95% confidence interval [ CI ]: 1.523-7.108, P =0.002) and female sex ( OR =5.146, 95% CI : 2.316-11.432, P < 0.001) were independent risk factor for IOH in patients undergoing DPMAS artificial liver support therapy.The ROC curve analysis of female sex+BMI ≤24 kg/m 2 showed that it had an AUC of 0.639 in predicting IOH ( P =0.002).The patients experiencing IOH had a 12-week survival rate of 55.77%(29/52) and a 24-week survival rate of 50%(26/52), and there were significant differences between the two groups in 12-and 24-week survival rates (12-week: 76.53% vs 55.77%, χ 2 =6.887, P =0.009;24-week: 74.49% vs 50.00%, χ 2 =9.080, P =0.003). Conclusion The risk of hypotension was higher in female patients and that with normal or low BMI during DPMAS artificial liver therapy.Patients with IOH had poor survival prognosis at 24 weeks after DPMAS therapy.

Outcomes in randomized controlled trials of acupuncture for vascular cognitive impairment during recent five years / 中国针灸

The existing problems in the outcomes of randomized controlled trials (RCTs) of acupuncture for vascular cognitive impairment (VCI) during recent five years are analyzed and suggestions are proposed. The RCTs of acupuncture for VCI were selected in PubMed, EMbase, Cochrane Library, Clinical Trials, CNKI database, Wanfang database, VIP database, SinoMed database and Chinese Clinical Trial Registry (ChiCTR) from January 1, 2015 to September 14, 2020. The outcomes were extracted and analyzed. As a result, 21 RCTs were included and the outcomes used were divided into 9 categories: clinical symptom/sign indexes, quality of life indexes, neuroimaging indexes, neuroelectrophysiology indexes, blood biochemical indexes, hemorheology indexes, TCM syndrome score indexes, clinical efficacy indexes, and safety indexes. Among them, the top three of the most used outcomes were clinical symptoms/signs indexes (21, 100.0%), clinical efficacy indexes (14, 66.7%) and quality of life indexes (12, 57.1%). In the RCTs of acupuncture for VCI, attention should be paid to distinguish the primary outcomes and secondary outcomes, adopt objective and standardized efficacy evaluation, and give consideration to report the outcomes of safety, health economic and TCM characteristic indexes.

Overview of systematic reviews of acupuncture for vascular cognitive impairment / 中国针灸

OBJECTIVE@#To overview the methodological quality, report quality and evidence quality of the systematic review (SR) of acupuncture for vascular cognitive impairment ( VCI ).@*METHODS@#The SRs regarding acupuncture for VCI were searched in PubMed, Cochrane Library, EMbase, CNKI, SinoMed, Wanfang and VIP databases. The retrieval period was from the establishment of the database to September 24, 2020. The report quality, methodological quality and evidence quality of the included SRs were evaluated by PRISMA statement, the AMSTAR 2 tool and the GRADE system.@*RESULTS@#A total of 22 SRs were included, including 102 outcome indexes. The methodological quality was generally low, with low scores on items 2, 5, 7, 10, 14, 15 and 16. The report quality was good, with scores ranging from 19 points to 24.5 points. The problems of report quality were mainly reflected in the aspects of structural abstract, program and registration, other analysis and funding sources. The level of outcome indexes of SRs was mostly low or very low, and the main leading factor was limitation, followed by inconsistency and inaccuracy.@*CONCLUSION@#Acupuncture for VCI is supported by low quality evidence of evidence-based medicine, but the methodological quality and evidence body quality of relevant SRs are poor, and the standardization is needed to be improved.

Graphene quantum dots with nitrogen-doped content dependence for highly efficient dual-modality photodynamic antimicrobial therapy and bioimaging.

Reactive oxygen species is the main contributor to photodynamic therapy. The results of this study show that a nitrogen-doped graphene quantum dot, serving as a photosensitizer, was capable of generating a higher amount of reactive oxygen species than a nitrogen-free graphene quantum dot in photodynamic therapy when photoexcited for only 3 min of 670 nm laser exposure (0.1 W cm-2), indicating highly improved antimicrobial effects. In addition, we found that higher nitrogen-bonding compositions of graphene quantum dots more efficiently performed photodynamic therapy actions than did the lower compositions that underwent identical treatments. Furthermore, the intrinsically emitted luminescence from nitrogen-doped graphene quantum dots and high photostability simultaneously enabled it to act as a promising contrast probe for tracking and localizing bacteria in biomedical imaging. Thus, the dual modality of nitrogen-doped graphene quantum dots presents possibilities for future clinical applications, and in particular multidrug resistant bacteria.