Optimization of Tungsten Heavy Alloy Cutting Parameters Based on RSM and Reinforcement Dung Beetle Algorithm.

Tungsten heavy alloys (WHAs) are an extremely hard-to-machine material extensively used in demanding applications such as missile liners, aerospace, and optical molds. However, the machining of WHAs remains a challenging task as a result of their high density and elastic stiffness which lead to the deterioration of the machined surface roughness. This paper proposes a brand-new multi-objective dung beetle algorithm. It does not take the cutting parameters (i.e., cutting speed, feed rate, and depth of cut) as the optimization objects but directly optimizes cutting forces and vibration signals monitored using a multi-sensor (i.e., dynamometer and accelerometer). The cutting parameters in the WHA turning process are analyzed through the use of the response surface method (RSM) and the improved dung beetle optimization algorithm. Experimental verification shows that the algorithm has better convergence speed and optimization ability compared with similar algorithms. The optimized forces and vibration are reduced by 9.7% and 46.47%, respectively, and the surface roughness Ra of the machined surface is reduced by 18.2%. The proposed modeling and optimization algorithms are anticipated to be powerful to provide the basis for the parameter optimization in the cutting of WHAs.

All-in-One Luminescent Lanthanide Coordination Polymer Nanoprobe for Facile Detection of Protein Kinase Activity.

This study developed a novel luminescent assay for kinase activity using metal-organic coordination polymer nanoparticles (Tb/ATP-Zn) as the probe. Tb/ATP-Zn, self-assembled by adenosine triphosphate (ATP), Zn2+, and Tb3+, is non-luminescent. Protein kinase A (PKA) can catalyze the transformation of ATP within Tb/ATP-Zn nanoparticles to adenosine diphosphate (ADP), which in turn effectively sensitizes the luminescence of Tb3+. Based on this mechanism, Tb/ATP-Zn can realize the facile luminescent "turn-on" sensing of protein kinase activity without the use of external ATP and substrate peptide. Under optimized conditions, the fluorescence intensities of Tb/ATP-Zn at 550 nm are linear with the PKA activity within a range of 0.3-1.5 U·µL-1. The LOD (S/N = 3) of this method is down to 0.001 U·µL-1. The presented assay also features high selectivity, long-term stability, fast response, and convenient operation. Furthermore, Tb/ATP-Zn was successfully employed for monitoring PKA activity in cell lysis solutions. Probe Tb/ATP-Zn is thus expectable to be a powerful tool for the practical study of PKA in relevant biological events.

The ketone body ß-hydroxybutyrate alleviates CoCrMo alloy particles induced osteolysis by regulating NLRP3 inflammasome and osteoclast differentiation.

BACKGROUND: Aseptic Loosening (AL) following periprosthetic osteolysis is the main long-term complication after total joint arthroplasty (TJA). However, there is rare effective treatment except for revision surgery, which is costly and painful to the patients. In recent years, the ketone body ß-hydroxybutyrate (BHB) has attracted much attention and has been proved to be beneficial in many chronic diseases. With respect to the studies on the ketone body ß-hydroxybutyrate (BHB), its anti-inflammatory ability has been widely investigated. Although the ketone body ß-hydroxybutyrate has been applied in many inflammatory diseases and has achieved considerable therapeutic efficacy, its effect on wear particles induced osteolysis is still unknown. RESULTS: In this work, we confirmed that the anti-inflammatory action of ß-hydroxybutyrate (BHB) could be reappeared in CoCrMo alloy particles induced osteolysis. Mechanistically, the ketone body ß-hydroxybutyrate (BHB) deactivated the activation of NLRP3 inflammasome triggered by CoCrMo alloy particles. Of note, this inhibitory action was independent of Gpr109a receptor as well as histone deacetylase (HDAC) suppression. Furthermore, given that butyrate, one kind of short chain fatty acid (SCFA) structurally related to ß-hydroxybutyrate (BHB), has been reported to be an inhibitor of osteoclast, thus we also investigate the effect of ß-hydroxybutyrate (BHB) on osteoclast, which was contributed to bone resorption. It was found that ß-hydroxybutyrate (BHB) did not only affect osteoclast differentiation, but also inhibit its function. Unlike the inflammasome, the effect of ß-hydroxybutyrate (BHB) on osteoclast may mainly rely on histone deacetylase (HDAC) suppression. CONCLUSIONS: In general, our study showed that the alleviation of osteolysis may owe to the effect of ß-hydroxybutyrate (BHB) on inflammasome deactivation and osteoclast.

Sociodemographic predictors and transportation patterns of COVID-19 infection and mortality.

BACKGROUND: The United States Centers for Disease Control and Prevention (CDC)-sanctioned prevention strategies have included frequent handwashing with soap and water, covering the mouth and nose with a mask when around others, cleaning and disinfecting maintaining a distance of at least 6 feet from others, etc. Although many of these recommendations are based upon observation and past infection control practices, it is important to combine and explore public data sets to identify predictors of infection, morbidity and mortality to develop more finely honed interventions, based on sociodemographic factors. METHOD: Cross-sectional study of both states in the US and counties in NY state. RESULTS: Population density was found to be significantly associated with state-level coronavirus infection and mortality rate (b = 0.49, 95% confidence interval (CI): 0.34, 0.64, P < .0001). States that have lower socioeconomic status, lower mean age and denser populations are associated with higher incidence rates. In regard to NY state, counties with a higher percentage of minority residents had higher COVID-19 mortality rates (b = 2.61, 95% CI: 0.36, 4.87, P = 0.023). Larger population cohorts were associated with lower COVID-19 mortality rates after adjusting for other variables in the model (b = -1.39, 95% CI: -2.07, -0.71, P < 0.001). Population density was not significantly associated with COVID-19 mortality rates after adjustment across counties in the NY state. Public ridership was not indicative of cases or mortality across states in the USA; however, it is a significant factor associated with incidence (but not mortality) in NY counties. CONCLUSION: Population density was the only significant predictor of mortality across states in the USA. Lower mean age, lower median household incomes and more densely populated states were at higher risk of COVID-19 infection. Population density was not found to be a significant independent variable compared to minority status and socioeconomic factors in the New York epicenter. Meanwhile, public ridership was found to be a significant factor associated with incidence in New York counties.

Modulation of Lipid Metabolism by Celastrol.

Hyperlipidemia, characterized by high serum lipids, is a risk factor for cardiovascular disease. Recent studies have identified an important role for celastrol, a proteasome inhibitor isolated from Tripterygium wilfordii Hook. F., in obesity-related metabolic disorders. However, the exact influences of celastrol on lipid metabolism remain largely unknown. Celastrol inhibited the terminal differentiation of 3T3-L1 adipocytes and decreased the levels of triglycerides in wild-type mice. Lipidomics analysis revealed that celastrol increased the metabolism of lysophosphatidylcholines (LPCs), phosphatidylcholines (PCs), sphingomyelins (SMs), and phosphatidylethanolamines (PEs). Further, celastrol reversed the tyloxapol-induced hyperlipidemia induced associated with increased plasma LPCs, PCs, SMs, and ceramides (CMs). Among these lipids, LPC(16:0), LPC(18:1), PC(22:2/15:0), and SM(d18:1/22:0) were also decreased by celastrol in cultured 3T3-L1 adipocytes, mice, and tyloxapol-treated mice. The mRNAs encoded by hepatic genes associated with lipid synthesis and catabolism, including Lpcat1, Pld1, Smpd3, and Sptc2, were altered in tyloxapol-induced hyperlipidemia, and significantly recovered by celastrol treatment. The effect of celastrol on lipid metabolism was significantly reduced in Fxr-null mice, resulting in decreased Cers6 and Acer2 mRNAs compared to wild-type mice. These results establish that FXR was responsible in part for the effects of celastrol in controlling lipid metabolism and contributing to the recovery of aberrant lipid metabolism in obesity-related metabolic disorders.

Lanthanide Functionalized Metal-Organic Coordination Polymer: Toward Novel Turn-On Fluorescent Sensing of Amyloid ß-Peptide.

Metal-organic coordination polymers (MOCPs) have been emerging as very attractive nanomaterials due to their tunable nature and diverse applications. Herein, using Tb3+ as the luminescence center, 1,3,5-benzenetricarboxylate (BTC) as building block and Cu2+ as the signal modulator as well as a recognition unit, we propose a novel and effective lanthanide functionalized MOCP (LMOCP) fluorescent sensor (Cu-BTC/Tb) for amyloid ß-peptide (Aß) monomer, a biomarker for Alzheimer disease (AD). Specifically, Cu-BTC/Tb, created by postsynthesis modification strategy under room temperature, is almost nonemissive due to the quenching effect of Cu2+ in the MOCP, exhilaratingly, the presence of Aß1-40 triggered a significant emission enhancement of Cu-BTC/Tb assay due to the high binding affinity of Aß1-40 for Cu2+ and the subsequent suppression of the quenching effect. In the assay, this LMOCP sensor shows high sensitivity with detection limit of 0.3 nM. Due to its capability to eliminate autofluorescence, Cu-BTC/Tb was also applied to the time-gated detection of Aß1-40 in human plasma with promising results. This work presents a novel strategy for the construction of functional luminescent LMOCP for sensitively turn-on fluorescent sensing of Aß1-40. We believe the proposed strategy would inspire the development of various LMOCP-based fluorescent assays or medical imaging platforms for advanced biological implementations.

A comprehensive review of the botany, phytochemistry, pharmacology, and toxicology of Murrayae Folium et Cacumen.

Ethnopharmacological relevance: Murrayae Folium et Cacumen (MFC) is a plant considered to be a traditional Chinese medicine with culinary value as well. The dry leaves and twigs of Murraya paniculata and M. exotica are used to treat stomach aches, rheumatism, toothaches, swelling, and insect and snake bites. They are also used to prepare spicy chicken dishes. Aim of the review: This review comprehensively summarizes the available information on the botanical characterization, phytochemistry, pharmacological activities, pharmacodynamics, pharmacokinetics, and toxicity of MFC. Methods: Relevant scientific literature up to August 2023 was included in the study. Chinese and English studies on MFC were collected from databases, including PubMed, Elsevier, Web of Science, Springer, Science Direct, Wiley, ACS, and CNKI (Chinese). Doctoral and Master's dissertations were also included. Results: In total, 720 compounds have been identified and reported in the literature, including flavonoids, coumarins, alkaloids, sterols, phenylpropenols, organic acids, spirocyclopentenones, and volatile oils. Flavonoids and coumarins are the two most important bioactive compounds responsible for these pharmacological activities. MFC has anti-inflammatory, anti-bacterial, anti-microbial, anti-diabetic, anti-tumor, anti-oxidant, anti-depressant, potential anti-Alzheimer's disease, chondroprotective, and analgesic properties. The pharmacological effects include interrupting the STAT3/NF-κB/COX-2 and EGFR signaling pathways, downregulating EpCAM expression, inhibiting NF-κB and ERK signals, inhibiting the EP/cAMP/PKA signaling pathway and miR-29a/Wnt/ß-catenin signaling activity, and upregulating Foxo3a expression. Conclusion: This review demonstrates that the chemical constituents, pharmacological activities, pharmacodynamics, pharmacokinetics, and toxicity of MFC support its use in traditional Chinese botanical medicines. MFC contains a wide range of chemical compounds. Flavonoids and coumarins promote strong pharmacological activity and, are low-toxicity natural phytomedicines that are widely used in medicine, food, ornamentation, and cosmetics, making MFC a promising compound for development and use in the treatment of several medical conditions.

Supramolecular sky-blue phosphorescent polymer iridium complexes for single-emissive-layer organic light-emitting diodes.

Novel supramolecular phosphorescent polymers (SPPs) are synthesized as a new class of solution-processable electroluminescent emitters. The formation of these SPPs takes advantage of the efficient non-bonding assembly between bis(dibenzo-24-crown-8)-functionalized iridium complex monomer and bis(dibenzylammonium)-tethered co-monomer, which is monitored by (1) H NMR spectroscopy and viscosity measurements. These SPPs show good film morphology and an intrinsic glass transition with a Tg of 94-116 °C. Noticeably, they are highly photoluminescent in solid state with quantum efficiency up to ca. 78%. The photophysical and electroluminescent properties are strongly dependent on the molecular structures of the iridium complex monomers.

The effect of different posterior inclinations of tibial component on tibiofemoral contact pressures after unicompartmental knee arthroplasty.

BACKGROUND: Different posterior inclinations of tibial component after unicompartmental knee arthroplasty (UKA) may lead to different biomechanical characteristics of the knee joint. This finite element study was designed to investigate the tibiofemoral contact pressures after UKA with different posterior inclinations of tibial component. METHODS: Finite element model of a healthy knee joint was constructed, and mobile-bearing (MB) UKA models with 5 different posterior inclinations (3°, 5°, 7°, 9° and 11°) of tibial components were simulated. The maximum contact pressures of tibial plateau cartilage in the lateral compartment and polyethylene insert in the medial compartment were calculated based on the ground reaction force and the angle of the knee flexion obtained by 3D motion capture system. RESULTS: The loading ratio of medial and lateral compartments during standing stance (medial 54.49%, lateral 45.51%) and tibial anterior displacement (134 N, 3.89 mm) of healthy knee was basically consistent with previous experimental data. The maximum contact pressures of the medial meniscus and lateral tibial plateau cartilage of the healthy knee during standing stance were 2.14 MPa and 1.57 MPa, respectively. At the static standing phase, the maximum contact pressures of the polyethylene insert decreased from 17.90 to 17.29 Mpa, and the maximum contact pressures of the tibial plateau cartilage in the lateral compartment increased from 0.81 to 0.92 Mpa following an increase in the posterior inclination of the tibial component. At the first peak of ground reaction force, the maximum contact pressures of polyethylene insert increased from 22.37 to 25.16 MPa, and the maximum contact pressures of tibial plateau cartilage in the lateral compartment increased from 3.03 to 3.33 MPa, with the increase in the posterior inclination of the tibial component. At the second peak of ground reaction force, the maximum contact pressures of polyethylene insert decreased from 2.34 to 2.22 MPa with the increase in posterior inclination of tibial component. CONCLUSION: The preoperative and postoperative finite element models of MB UKA were well established. The results showed that the maximum contact pressures of the polyethylene insert did not change significantly with the increase in the posterior inclination of the tibial prosthesis, while the maximum contact pressures of the tibial plateau cartilage of the lateral compartment increased when the posterior inclination of the tibial prosthesis was > 7°. Our results also show that the maximum contact pressures were greater with an excessive inclination angle (11°) of the tibial component, and the pressures of the tibial plateau cartilage in the lateral compartment were more concentrated on the posterior area. This study, therefore, proposes that excessive osteotomy should be avoided.

Successful treatment of new-onset diabetes mellitus and IgA nephropathy after COVID-19 vaccination: a case report.

De novo glomerular injuries or relapse of nephropathy following COVID-19 vaccine has been reported. Here we present the first case of successful treatment of new-onset diabetes mellitus and biopsy-proven IgA nephropathy after COVID-19 vaccination. A 56-year-old man with no known medical history of renal dysfunction or diabetes mellitus developed both within 3 months after receiving a third dose of inactivated COVID-19 vaccine (Vero cells). His symptoms were characterized by brown urine, severe dry mouth, and excessive thirst. Randomly acquired blood glucose levels exceeded 33.3 mmol/L. A kidney biopsy showed IgA nephropathy. He was started on insulin for glycemic control. After glucocorticoid and cyclophosphamide treatment, oral tablets of repaglinide, combined with acarbose, controlled blood glucose and stabilized kidney function. This case is unique because the kidneys and pancreas were simultaneously affected by the vaccine. Successful treatment of the disease proved that cyclophosphamide combined with glucocorticoids were effective and that blood glucose was successfully controlled. This treatment option could be useful in similar cases in the future.

Development of a novel ratiometric electrochemical sensor for monitoring ß-galactosidase in Parkinson's disease model mice.

Rapid, simple, accurate and highly sensitive detection of enzymes is essential for early screening and clinical diagnosis of many diseases. In this study, we report the fabrication of a turn-on ratiometric electrochemical sensor for the in situ determination of ß-Galactosidase (ß-Gal) based on surface engineering and the design of a molecular probe (Pygal) specific for ß-Gal recognition. First, Pygal probe was synthesized and characterized, and then co-assembled with the methylene blue (MB) internal reference probe on the surface of single-wall carbon nanotubes (SWCNT)-modified carbon fiber microelectrode (CFME). The resulting CFME/SWCNT/MB + Pygal sensor is activated in the presence of ß-Gal giving one peak at 0.33 V originating from the oxidation of the product of Pygal enzymatic hydrolysis (PyOH). Another oxidation peak attributed to MB appears simultaneously at -0.28 V allowing the construction of a ratiometric electrochemical sensor for ß-Gal detection with improved sensitivity and accuracy. The sensor showed a linear response to ß-Gal in a wide concentration range from 1.5 to 30 U L-1 and a low detection limit of 0.1 U L-1. Moreover, the sensor demonstrated excellent selectivity against several biologically relevant hydrolases and redox-active molecules. Finally, the combination of excellent electrochemical performance and favorable physicochemical properties of CFME allowed the determination of ß-Gal in the whole blood of Parkinson's Disease (PD) model mice. The workflow reported in this study provides a strategy for the design and development of sensors for the in vivo monitoring of other enzymes important for the early diagnosis of different health issues.

Propionate and butyrate attenuate macrophage pyroptosis and osteoclastogenesis induced by CoCrMo alloy particles.

BACKGROUND: Wear particles-induced osteolysis is a major long-term complication after total joint arthroplasty. Up to now, there is no effective treatment for wear particles-induced osteolysis except for the revision surgery, which is a heavy psychological and economic burden to patients. A metabolite of gut microbiota, short chain fatty acids (SCFAs), has been reported to be beneficial for many chronic inflammatory diseases. This study aimed to investigate the therapeutic effect of SCFAs on osteolysis. METHODS: A model of inflammatory osteolysis was established by applying CoCrMo alloy particles to mouse calvarium. After two weeks of intervention, the anti-inflammatory effects of SCFAs on wear particle-induced osteolysis were evaluated by Micro-CT analysis and immunohistochemistry staining. In vitro study, lipopolysaccharide (LPS) primed bone marrow-derived macrophages (BMDMs) and Tohoku Hospital Pediatrics-1 (THP-1) macrophages were stimulated with CoCrMo particles to activate inflammasome in the presence of acetate (C2), propionate (C3), and butyrate (C4). Western blotting, Enzyme-linked immunosorbent assay, and immunofluorescence were used to detect the activation of NLRP3 inflammasome. The effects of SCFAs on osteoclasts were evaluate by qRT-PCR, Western blotting, immunofluorescence, and tartrate-resistant acid phosphatase (TRAP) staining. Additionally, histone deacetylase (HDAC) inhibitors, agonists of GPR41, GPR43, and GPR109A were applied to confirm the underlying mechanism of SCFAs on the inflammasome activation of macrophages and osteoclastogenesis. RESULTS: C3 and C4 but not C2 could alleviate wear particles-induced osteolysis with fewer bone erosion pits (P < 0.001), higher level of bone volume to tissue volume (BV/TV, P < 0.001), bone mineral density (BMD, P < 0.001), and a lower total porosity (P < 0.001). C3 and C4 prevented CoCrMo alloy particles-induced ASC speck formation and nucleation-induced oligomerization, suppressing the cleavage of caspase-1 (P < 0.05) and IL-1ß (P < 0.05) stimulated by CoCrMo alloy particles. C3 and C4 also inhibited the generation of Gasdermin D-N-terminal fragment (GSDMD-NT) to regulate pyroptosis. Besides, C3 and C4 have a negative impact on osteoclast differentiation (P < 0.05) and its function (P < 0.05), affecting the podosome arrangement and morphologically normal podosome belts formation. CONCLUSION: Our work showed that C3 and C4 are qualified candidates for the treatment of wear particle-induced osteolysis.

A novel in vivo siRNA delivery system specifically targeting dendritic cells and silencing CD40 genes for immunomodulation.

Translation of small interfering RNA (siRNA)-based approaches into practical therapeutics is limited because of lack of an effective and cell-specific delivery system. Herein, we present a new method of selectively delivering siRNA to dendritic cells (DCs) in vivo using CD40 siRNA-containing immunoliposomes (siILs) that were decorated with DC-specific DEC-205 mAb. Administration of CD40 siILs resulted in DC-specific cell targeting in vitro and in vivo. On treatment with CD40 siILs, the expression of CD40 in DCs, as well allostimulatory activity was inhibited. In vivo administration resulted in selective siRNA uptake into immune organs and functional immune modulation as assessed using a model antigen. In conclusion, this is the first demonstration of DC-specific siRNA delivery and gene silencing in vivo, which highlights the potential of DC-mediated immune modulation and the feasibility of siRNA-based clinical therapy.

Lanthanide coordination polymer probe for time-gated luminescence sensing of pH in undiluted human serum.

Lanthanide coordination polymers (LCPs) have emerged as fascinating materials because of their specific structure and properties. In this work, utilizing hydrosoluble biomolecule of guanosine-5'-monophosphate (GMP) as bridging linker, lanthanide terbium ions (Tb3+) as metal nodes, and silver ions (Ag+) as sensitizers, we synthesized a pH responsive luminescent lanthanide CP probe of Tb/GMP/Ag. The probe possesses high luminescence due to the sensitization of Ag+; While in alkaline solutions, Ag+ in Tb/GMP/Ag immediately binds to OH-, forming Ag2O precipitation and resulting in a distinct fluorescence quenching of Tb/GMP/Ag. This probe displays high selectivity for OH- and a broader pH detection range of 7.5-13.0. In addition, based on the high anti-interference ability in serum, we applied Tb/GMP/Ag to measure pH in undiluted human serum samples, yielding satisfactory results.

Smart lanthanide coordination polymer fluorescence probe for mercury(II) determination.

Lanthanide coordination polymers (LCPs) have recently emerged as attractive biosensor materials due to their flexible components, high tailorable properties and unique luminescence features. In this work, we designed a smart LCP probe of Tb-CIP/AMP {(CIP, ciprofloxacin) (AMP, adenosine monophosphate)} for Hg(2+) detection by using lanthanide ions as metal nodes, CIP as ligand molecule, and AMP as bridging linker and recognition unit. Tb-CIP/AMP emits strong green luminescence due to the inclusion of AMP, which withdraws the coordinated water molecules and shields Tb(3+) from the quenching effect of O-H vibration in water molecules. The subsequent addition of Hg(2+) into Tb-CIP/AMP can strongly quench the fluorescence because of the specific coordination interaction between AMP and Hg(2+). As a kind of Hg(2+) nanosensor, the probe exhibited excellent selectivity for Hg(2+) and high sensitivity with detection limit of 0.16 nM. In addition, the probe has long fluorescence lifetime up to millisecond and has been applied to detect Hg(2+) in drinking water and human urine samples with satisfactory results. We envision that our strategy, in the future, could be extended to the designation of other LCP-based hypersensitive time-gated luminescence assays in biological media and biomedical imaging.

Electrochemical detection of dopamine in the presence of ascorbic acid using PVP/graphene modified electrodes.

Graphene (GR) was synthesized through electrochemical reduction of graphene oxide and characterized by spectroscopic and electrochemical techniques. Polyvinylpyrrolidone (PVP)/graphene modified glassy carbon electrode (PVP/GR/GCE) was prepared and applied for the fabrication of dopamine (DA) sensors without the interference of ascorbic acid (AA). Compared to bare GCE, an increase of current signal was observed, demonstrating that PVP/GR/GCE exhibited favorable electron transfer kinetics and electrocatalytic activity towards the oxidation of dopamine. Furthermore, PVP/GR/GCE exhibited good ability to suppress the background current from large excess ascorbic acid. Amperometric response results show that the PVP based sensor displayed a wide linear range of 5×10(-10) to 1.13×10(-3) mol/L DA with a correlation coefficient of 0.9990 and a detection limit of 0.2 nM (S/N=3). The determination of dopamine in urine and human serum samples were studied.

[Research on population structure and distribution characteristic of indigenous microorganism in post-polymer-flooding oil reservoir].

Denaturing gradient gel electrophoresis (DGGE) method and principal component analysis (PCA) method were used to analyze the structures of microorganism population in injection wells and production wells of a post-polymer-flooding oil reservoir in Daqing oil field. The results showed that the dominant species in injection wellhead were aerobic bacteria Pseudomonas and Acinenobacter. Facultative anaerobic bacteria Enterbacter was the dominant bacteria in near area of injection wells. Bacteria detected in production wells included Thauera, Clostridia, Pseudomonas, Petrobacter and some uncultured bacteria. Methanosaeta turned out to be the only archaea detected in injection wells, which was an aceticlastic methane-producing archaeon. Archaea detected in production wells consisted of Methanomicrobium, Methanospirillum and Methanobacterium. In general, aerobic bacteria, facultative anaerobe, and strictly anaerobic bacteria distributed successively from injection wells to production wells in this block. The dominant populations of archaea were different between injection wells and production wells, while were influenced by different environments and microbial metabolism products.

Synthesis, biocompatibility and cell labeling of L-arginine-functional beta-cyclodextrin-modified quantum dot probes.

A series of quantum dots (QDs), CdSe, CdSe/CdS and CdSe/ZnSe, coated with L-arginine-modified beta-cyclodextrin (beta-CD-L-Arg) were prepared in a solution of H2O and hexane by ultrasonic method and characterized using PL, UV-vis, TEM, EDX and FTIR techniques. We observed that beta-CD-L-Arg-coated QDs are water-soluble and stable with high colloidal properties in water. Their photophysical properties are similar to those of trioctylphosphine oxide (TOPO)-coated nanocrystals. The quantum yield (QY) of beta-CD-L-Arg/CdSe/ZnSe QDs in water is 68%, which is much higher than those of beta-CD-L-Arg/CdSe/CdS (26%) and beta-CD-L-Arg/CdSe (13%). The in vitro cytotoxicity of these QDs was evaluated in ECV-304, SH-SY5Y and Hela cells and low cytotoxicity was observed. In particular, the beta-CD-L-Arg/CdSe/ZnSe QDs presented lower cytotoxicity to these cells (CC(50) value is 173 microg/mL in ECV-304 cells for 48h). This may be due to the presence of the ZnSe and beta-CD-L-Arg outlayer, which may improve the biocompatibility of QDs. The QDs were further investigated for biological labeling in ECV-304 cells using confocal laser scanning fluorescence microscopy. We found that these QDs were capable of localing to the cytoplasm of cells. These results demonstrate that the beta-CD-L-Arg-coated QDs could be used as a potential photoluminescent nanocrystal probing agent with good biocompatibility.