Radiolabeled Liposomes for Nuclear Imaging Probes.

Quantitative nuclear imaging techniques are in high demand for various disease diagnostics and cancer theranostics. The non-invasive imaging modality requires radiotracing through the radioactive decay emission of the radionuclide. Current preclinical and clinical radiotracers, so-called nuclear imaging probes, are radioisotope-labeled small molecules. Liposomal radiotracers have been rapidly developing as novel nuclear imaging probes. The physicochemical properties and structural characteristics of liposomes have been elucidated to address their long circulation and stability as radiopharmaceuticals. Various radiolabeling methods for synthesizing radionuclides onto liposomes and synthesis strategies have been summarized to render them biocompatible and enable specific targeting. Through a variety of radionuclide labeling methods, radiolabeled liposomes for use as nuclear imaging probes can be obtained for in vivo biodistribution and specific targeting studies. The advantages of radiolabeled liposomes including their use as potential clinical nuclear imaging probes have been highlighted. This review is a comprehensive overview of all recently published liposomal SPECT and PET imaging probes.

Negative Pressure Membrane Distillation for Excellent Gypsum Scaling Resistance and Flux Enhancement.

Membrane distillation (MD) has potential to become a competitive technology for managing hypersaline brine but not until the critical challenge of mineral scaling is addressed. The state-of-the-art approach for mitigating mineral scaling in MD involves the use of superhydrophobic membranes that are difficult to fabricate and are commercially unavailable. This study explores a novel operational strategy, namely, negative pressure direct contact membrane distillation (NP-DCMD) that can minimize mineral scaling with commercially available hydrophobic membranes and at the same time enhance the water vapor flux substantially. By applying a negative gauge pressure on the feed stream, NP-DCMD achieved prolonged resistance to CaSO4 scaling and a dramatic vapor flux enhancement up to 62%. The exceptional scaling resistance is attributable to the formation of a concave liquid-gas under a negative pressure that changes the position of the water-air interface to hinder interfacial nucleation and crystal growth. The substantial flux enhancement is caused by the reduced molecular diffusion resistance within the pores and the enhanced heat transfer kinetics across the boundary layer in NP-DCMD. Achieving substantial performance improvement in both the scaling resistance and vapor flux with commercial membranes, NP-DCMD is a significant innovation with vast potential for practical adoption due to its simplicity and effectiveness.

Therapeutic effect of a novel bioactive glass-ceramics on early caries lesions: a single-center, randomized controlled clinical trial.

OBJECTIVES: To investigate the therapeutic effect of a novel bioactive glass-ceramics (BGC) called Huaxi BGC (HX-BGC) on early caries lesions. MATERIALS AND METHODS: A total of 195 patients who meeting inclusion criteria were recruited and randomized to three groups in a 1:1:1 ratio. The patients in the treatment group received fluoride varnish which contained 5% sodium fluoride (NaF) or distilled water which contained 7.5% HX-BGC once a month for 3 months, and the control group received placebos. Quantitative light-induced fluorescence (QLF) images were taken at baseline and at the 1-month and 3-month follow-ups. RESULTS: The three groups had similar baseline characteristics, including age, gender, and QLF parameters (ΔF, area, and ΔQ). Compared with baseline, the ΔQ values were significantly decreased in the HX-BGC and NaF groups at 1 and 3 months (p<0.005), while no statistically significant changes were found in that of the control group. After adjusting for baseline measurements, both of the 5% NaF and 7.5% HX-BGC showed a significant therapeutic effect in the treatment of initial enamel lesions at 1 month and 3 months, when compared to those receiving placebos (ΔQ, p<0.05). Moreover, the ΔQ value of the HX-BGC group decreased by a slightly more amount than that of the NaF group at 1 month (p=0.048). Similar trends were also found for the values of ΔF and area. CONCLUSION: Our results suggest that HX-BGC may serve as a promising bioactive material for the treatment of early caries lesions. CLINICAL RELEVANCE: HX-BGC holds a great promise to be used as a novel bioactive material for the treatment of early caries lesions.

Novel findings on anti-plaque effects of stannous fluoride.

PURPOSE: To evaluate the antiplaque effects for 0.454% bioavailable gluconate chelated stannous fluoride (SnF2) dentifrices versus controls by clinical model, plaque index, tooth surface and tooth type in a pooled analysis. METHODS: Randomized controlled trials (RCTs) were conducted to evaluate plaque effects of SnF2 dentifrices from the same formulation family over the past 30 years. Forty-four 4-day and longer-term (≥ 2 weeks) RCTs conducted in six countries with 3,336 subjects using Turesky Modified Quigley-Hein Plaque Index, Rustogi Modification of the Navy Plaque Index, Digital Plaque Imaging Analysis, and Silness and Löe Plaque Index were included. RESULTS: In 13 and 11 longer-term studies assessing SnF2 dentifrice versus a negative or positive control, respectively, standardized differences in average plaque score of -1.15 (95% CI: -1.61, -0.69) and -0.74 (95% CI: -1.20, -0.28) were observed (P ≤ 0.011), favoring SnF2. Reductions represented a 19% and 16% benefit versus the negative and positive control, respectively. In 18 and five 4-day studies assessing SnF2 dentifrice versus a negative (NaF/SMFP) or positive (triclosan/chlorhexidine) control, respectively, differences in average 4-day plaque score of -0.27 (95% CI: -0.31, -0.23) and -0.15 (95% CI: -0.25, -0.06) were observed (P≤ 0.001) favoring SnF2. Reductions represented a 14% and 11% benefit versus the negative and positive control, respectively. Significant antiplaque benefits for SnF2 dentifrice were seen regardless of clinical model, plaque index, tooth surface or type, including brushed and unbrushed surfaces (P≤ 0.049). CLINICAL SIGNIFICANCE: Bioavailable gluconate chelated SnF2 dentifrices showed consistent plaque inhibition versus negative and positive controls across all conditions evaluated. Importantly, the effect on unbrushed surfaces illustrated the significant plaque inhibition benefit of SnF2 beyond mechanical plaque removal.

Automatic localization of cephalometric landmarks based on convolutional neural network.

INTRODUCTION: Cephalometry plays an important role in the diagnosis and treatment of orthodontics and orthognathic surgery. This study intends to develop an automatic landmark location system to make cephalometry more convenient. METHODS: In this study, 512 lateral cephalograms were collected, and 37 landmarks were included. The coordinates of all landmarks in the 512 films were obtained to establish a labeled dataset: 312 were used as a training set, 100 as a validation set, and 100 as a testing set. An automatic landmark location system based on the convolutional neural network was developed. This system consisted of a global detection module and a locally modified module. The lateral cephalogram was first fed into the global module to obtain an initial estimate of the landmark's position, which was then adjusted with the locally modified module to improve accuracy. Mean radial error (MRE) and success detection rate (SDR) within the range of 1-4 mm were used to evaluate the method. RESULTS: The MRE of our validation set was 1.127 ± 1.028 mm, and SDR of 1.0, 1.5, 2.0, 2.5, 3.0, and 4.0 mm were respectively 45.95%, 89.19%, 97.30%, 97.30%, and 97.30%. The MRE of our testing set was 1.038 ± 0.893 mm, and SDR of 1.0, 1.5, 2.0, 2.5, 3.0, and 4.0 mm were respectively 54.05%, 91.89%, 97.30%, 100%, 100%, and 100%. CONCLUSIONS: In this study, we proposed a new automatic landmark location system on the basis of the convolutional neural network. The system could detect 37 landmarks with high accuracy. All landmarks are commonly used in clinical practice and could meet the requirements of different cephalometric analysis methods.

A randomized, controlled comparison of a stannous-containing dentifrice for reducing gingival bleeding and balancing the oral microbiome relative to a positive control.

PURPOSE: To evaluate the effect of a stannous-containing fluoride dentifrice on gingival health and on the composition of the oral microbiome versus a positive control dentifrice over 2 weeks, in a population of healthy adults with self-reported sub-optimal oral health at baseline. METHODS: This was a randomized, controlled, double-blind clinical study. 87 subjects with self-reported sub-optimal oral health at enrollment were randomized to brush twice daily with either an experimental dentifrice (n= 43) or a marketed positive control dentifrice (n= 43), both containing stannous chloride and 0.321% sodium fluoride. All subjects used a soft, manual toothbrush that was provided. The Mazza modification of gingival papillary bleeding Index (Mazza GI) was used to assess gingivitis at baseline and at Week 2. Supragingival plaque was collected for microbiome composition analyses at baseline, Week 1, and Week 2. RESULTS: 83 subjects completed the study. Baseline means were balanced between the treatment groups (P> 0.34). At Week 2, the positive control dentifrice demonstrated a 63.8% statistically significant (P< 0.0001) reduction relative to baseline for Mazza number of gingival bleeding sites. The experimental stannous containing dentifrice provided a comparable 63.5% gingival bleeding reduction versus baseline. There was no significant (P= 0.96) difference between the two dentifrices for either Mazza GI score or number of bleeding sites measured. The microbiome composition analysis at Week 1 found that 28 gingivitis-associated bacterial genera, including Porphyromonas, Tannerella, and Fusobacterium, were significantly inhibited in both dentifrice groups when compared to baseline, while the relative abundance of genera associated with oral health, such as Rothia, Streptococcus, Haemophilus, and Lautropia, was significantly elevated after treatment. These improvements in the oral ecosystem were sustained at Week 2. CLINICAL SIGNIFICANCE: An experimental stannous-containing sodium fluoride dentifrice significantly reduced gingival bleeding comparable to a positive control, and both dentifrices promoted a shift in the oral microbiome towards those genera associated with oral health in a subject population with self-reported sub-optimal oral health at baseline.

A clinical study to assess the gingivitis reduction efficacy of a novel stannous-containing fluoride dentifrice.

PURPOSE: To assess the gingivitis reduction efficacy of a novel stannous-containing fluoride dentifrice relative to a negative control. METHODS: 100 generally healthy adults with 10 or more gingival bleeding sites based on the Mazza Modification of the Papillary Bleeding Index (Mazza GI) were enrolled into a 2-week randomized, controlled, double-blind, single-center, two-treatment, parallel group clinical study. The subjects were randomly assigned to the stannous-containing dentifrice group (experimental group) or the sodium fluoride dentifrice group (negative control group). An oral examination and Mazza GI examination were conducted at Baseline, Day 3 and Week 2 post-baseline by a qualified dental examiner. RESULTS: 98 subjects completed the study. The experimental group provided a significant reduction in Mazza GI scores and number of bleeding sites relative to baseline at Day 3 and Week 2 (P< 0.0001). The negative control did not provide significant reductions versus baseline for either measure at either timepoint (P> 0.3). At Day 3, the experimental group provided a statistically significant reduction of Mazza GI scores and number of bleeding sites compared with the negative control group (P< 0.0001). At Week 2, the experimental group showed 24.11% lower Mazza GI scores and 54.81% fewer bleeding sites than the negative control group (P< 0.0001). CLINICAL SIGNIFICANCE: The results demonstrated that the novel stannous-containing fluoride dentifrice had a superior anti-gingivitis effect compared to the sodium fluoride negative control dentifrice, which was evident as quickly as 3 days after use and further improved after 2 weeks of usage.

Randomized clinical trial assessing anti-gingivitis efficacy of two stannous fluoride dentifrices and zinc/arginine dentifrice.

PURPOSE: To evaluate the anti-gingivitis efficacy of two bioavailable stannous fluoride (SnF2) dentifrices versus a zinc/arginine dentifrice and a negative control dentifrice, and to compare the plaque control benefits. METHODS: This was a single-center, randomized, controlled, four-treatment, parallel-group, double-blind, 3-month clinical trial. Healthy adult subjects with gingivitis were randomly assigned to one of four different dentifrice treatment groups: SnF2 dentifrice A, SnF2 (1,100 ppm F) + sodium fluoride (350 ppm F) + sodium hexametaphosphate (Procter & Gamble); SnF2 dentifrice B, SnF2 (1,100 ppm F) + sodium fluoride (350 ppm F) + citrate (Procter & Gamble); Zn/Arg dentifrice, zinc/arginine + sodium fluoride (1,450 ppm F) (Colgate-Palmolive); negative control dentifrice, sodium monofluoro-phosphate (1,000 ppm F) + sodium fluoride (450 ppm F) (Colgate-Palmolive). Subjects brushed with their assigned treatment dentifrice and an assigned manual toothbrush (Oral-B Indicator) for 1 minute, twice daily, for the duration of the study. Gingivitis was assessed at Baseline and at Weeks 2, 4 and 12 by calculating the total number of gingival bleeding sites using the Gingival Bleeding Index, and plaque was assessed at Baseline and at Week 12 using the Turesky Modified Quigley-Hein Index. A repeated measures model was carried out across Weeks 2, 4, and 12 to determine bleeding efficacy (total number of bleeding sites). An ANCOVA with baseline plaque as the covariate was used to evaluate plaque efficacy at Week 12. RESULTS: 161 subjects were randomized (mean age= 38.8 years). 154 subjects completed the study and 153 had evaluable data at Week 12. The mean (SD) number of Baseline bleeding sites overall was 78.74 (31.16) with no significant difference between groups (P= 0.537). SnF2 dentifrice A significantly reduced the number of bleeding sites relative to the negative control dentifrice at Weeks 2, 4 and 12 by 15.4%, 13.7% and 17.2%, respectively. SnF2 dentifrice B significantly reduced the number of bleeding sites relative to the negative control dentifrice at Week 4 by 13.9% (P= 0.041). Relative to the Zn/Arg dentifrice, SnF2 dentifrice A produced significantly greater reductions in gingival bleeding sites at Weeks 2, 4 and 12 by 23.4%, 17.2% and 20.9%, respectively (P≤ 0.007). SnF2 dentifrice B produced significantly greater bleeding reductions versus the Zn/Arg dentifrice at Weeks 4 and 12 by 17.4% and 14.4%, respectively (P≤ 0.035). The Zn/Arg dentifrice did not differ significantly in the number of bleeding sites (P≥ 0.127) or plaque (P= 0.175) relative to the negative control dentifrice. Both SnF2 dentifrices significantly reduced plaque levels (P≤ 0.029) relative to both negative control dentifrice and Zn/Arg dentifrice at Week 12. All dentifrices were well tolerated. CLINICAL SIGNIFICANCE: Two different SnF2 dentifrices showed significantly reduced gingival bleeding and plaque levels relative to a Zn/arginine dentifrice.

Organic Electrochemical Transistor for in Situ Detection of H2O2 Released from Adherent Cells and Its Application in Evaluating the In Vitro Cytotoxicity of Nanomaterial.

Detection of hydrogen peroxide (H2O2) produced by living cells is very significant to fully understand its roles in cellular physiology, as well as providing reliable diagnosis of pathological conditions. However, in situ detection of H2O2 released from adherent cells in cellular culture medium is still insufficiently achieved. Here, we report an electrochemical platform for in situ detection of H2O2 produced by adherent cells in cellular culture medium. It is based on the use of organic electrochemical transistor (OECT) fabricated on a flexible poly(ethylene terephthalate) substrate and Transwell support. A screen-printed carbon paste electrode was modified with carbon nanotubes and platinum nanoparticles and served as the gate of the device. Under optimal conditions, this device exhibits good modulation and sensitivity. It works in the 0.5 µM to 0.1 mM H2O2 concentration range and has a 0.2 µM detection limit. The cells were seeded and grew on the Transwell membrane. Upon being stimulated by N-formylmethionyl-leucyl-phenylalanine peptide, H2O2 produced by the adherent cells diffused into the bottom chamber of the Transwell and was in situ detected by OECT. Moreover, evaluating in vitro cytotoxicity of the nanomaterial using the OECT-Transwell platform was realized. This simple electrochemical platform would be of great interest for in vitro cytotoxicity, cellular physiology study, and diagnosis of pathological conditions.

Trauma induced tissue survival in vitro with a muscle-biomaterial based osteogenic organoid system: a proof of concept study.

BACKGROUND: The translation from animal research into the clinical environment remains problematic, as animal systems do not adequately replicate the human in vivo environment. Bioreactors have emerged as a good alternative that can reproduce part of the human in vivo processes at an in vitro level. However, in vitro bone formation platforms primarily utilize stem cells only, with tissue based in vitro systems remaining poorly investigated. As such, the present pilot study explored the tissue behavior and cell survival capability within a new in vitro skeletal muscle tissue-based biomaterial organoid bioreactor system to maximize future bone tissue engineering prospects. RESULTS: Three dimensional printed ß-tricalcium phosphate/hydroxyapatite devices were either wrapped in a sheet of rat muscle tissue or first implanted in a heterotopic muscle pouch that was then excised and cultured in vitro for up to 30 days. Devices wrapped in muscle tissue showed cell death by day 15. Contrarily, devices in muscle pouches showed angiogenic and limited osteogenic gene expression tendencies with consistent TGF-ß1, COL4A1, VEGF-A, RUNX-2, and BMP-2 up-regulation, respectively. Histologically, muscle tissue degradation and fibrin release was seen being absorbed by devices acting possibly as a support for new tissue formation in the bioceramic scaffold that supports progenitor stem cell osteogenic differentiation. CONCLUSIONS: These results therefore demonstrate that the skeletal muscle pouch-based biomaterial culturing system can support tissue survival over a prolonged culture period and represents a novel organoid tissue model that with further adjustments could generate bone tissue for direct clinical transplantations.

Penetrating glassy carbon neural electrode arrays for brain-machine interfaces.

This paper presents a fabrication method for glassy carbon neural electrode arrays that combines 3D printing and chemical pyrolysis technology. The carbon electrodes have excellent biological compatibility and can be used in neural signal recording. A pretreated Si wafer is used as the substrate for 3D printing, and then, stereolithography 3D printing technology is employed to print photosensitive resin into a cone shape. Next, chemical pyrolysis is applied to convert the 3D prints into glassy carbon electrodes and modify the electrochemical performance of the carbon electrodes. Finally, the glassy carbon electrodes are packed with conductive wires and PDMS. The proposed fabrication method simplifies the manufacturing process of carbon materials, and electrodes can be fabricated without the need of deep reactive ion etching (DRIE). The height of the carbon electrodes is 1.5 mm, and the exposure area of the tips is 0.78 mm2, which is convenient for the implantation procedure. The specific capacitance of the glassy carbon arrays is higher than that of a platinum electrode (9.18 mF/cm2 vs 3.32 mF/cm2, respectively), and the impedance at 1 kHz is lower (7.1 kΩ vs 8.8 kΩ). The carbon electrodes were tested in vivo, and they showed excellent performance in neural signal recording. The signal-to-noise ratio of the carbon electrodes is 50.73 ± 6.11, which is higher than that of the Pt electrode (20.15 ± 5.32) under the same testing conditions. The proposed fabrication method of glassy carbon electrodes provides a novel approach to manufacture penetrating electrodes for nerve interfaces in biomedical engineering and microelectromechanical systems.

Analysis of the association of TNF-α, IL-1A, and IL-1B polymorphisms with peri-implantitis in a Chinese non-smoking population.

OBJECTIVES: The purpose of this study was to investigate whether the genetic variations which could regulate inflammatory responses were associated with the risk of peri-implantitis. MATERIALS AND METHODS: We evaluated three genetic variants including tumor necrosis factor-alpha (TNF-α) - 308G/A, interleukin-1 alpha (IL-1A) - 889C/T, and IL-1 beta (IL-1B) + 3954C/T, as risk factors for peri-implantitis, in a total of 144 patients with peri-implantitis and 174 healthy controls in a Chinese non-smoking population. RESULTS: Logistic regression analyses revealed that subjects carrying the T allele of IL-1A - 889C/T and IL-1B + 3954C/T had a significant 2.27-2.47-fold (CT, OR [95% CI] = 2.27 [1.12-4.58], p = 0.021; TT, OR [95% CI] = 2.47 [1.32-4.69], p = 0.006) and 1.9-1.99-fold (CT, OR [95% CI] = 1.99 [1-3.93], p = 0.041; TT, OR [95% CI] = 1.9 [1.08-3.43], p = 0.03) increased risk of peri-implantitis, respectively, when using the CC genotype as a reference point. And subjects carrying the TT genotype of IL-1A - 889C/T or IL-1B + 3954C/T also had significantly higher periodontal variables including peri-implant pocket depth (PPD), bleeding on probing (BOP), gingival index (GI), plaque index (PI), calculus index (CI), and clinical attachment level (CAL) (p < 0.05). However, no associations were found between the TNF-α - 308G/A polymorphism and the risk of peri-implantitis. CONCLUSIONS: Our results suggest that the IL-1A - 889C/T or IL-1B + 3954C/T genetic polymorphisms were associated with the risk of peri-implantitis and periodontal status. CLINICAL RELEVANCE: Genetic polymorphisms are constant and can be measured before disease onset, thus it could be of great benefit for treatment planning and prognosis in an early stage.

The relative clinical efficacy of three 0.454% stannous fluoride dentifrices for the treatment of gingivitis over 3 months.

PURPOSE: To assess the safety and efficacy of three stannous fluoride (SnF2) dentifrices in the reduction of gingivitis versus a negative control dentifrice. METHODS: This was a randomized, controlled, double-blind, four-treatment parallel group study. 120 healthy adult volunteers with established gingivitis were enrolled and randomly assigned to one of four dentifrice treatment groups (30/group): 0.454% SnF2 + citrate dentifrice A; 0.454% SnF2 + sodium hexametaphosphate dentifrice B; 0.454% SnF2 + pyrophosphate dentifrice C; or 0.76% sodium monofluorophosphate negative control group. Subjects brushed with their assigned dentifrice and an assigned regular manual toothbrush (Oral-B Indicator) for 1 minute twice daily for 12 weeks. Number of gingival bleeding sites and Löe-Silness Gingival Index (LSGI) scores were assessed at baseline and at Weeks 2, 4 and 12. RESULTS: 120 subjects were enrolled and 112 completed the trial. Subjects had an average age (SD) of 39.31 (14.5) years; 67% of subjects were female. Overall baseline means (SD) were 81.2 (25.6) for number of bleeding sites and 1.51 (0.197) for mean LSGI score. Baseline disease levels were balanced across all treatment groups. At Week 2, SnF2 dentifrices A and B demonstrated a significant reduction in gingival bleeding sites versus the negative control; however, SnF2 dentifrice C was not significantly different from the negative control (P= 0.15). At Weeks 4 and 12, all SnF2 dentifrices demonstrated a significant gingival bleeding site reduction versus the negative control (P< 0.001). At Weeks 2, 4 and 12, the SnF2 dentifrices were rank ordered dentifrice A > dentifrice B > dentifrice C for reduction in gingival bleeding sites (P< 0.001). The same trends were seen for LSGI scores. CLINICAL SIGNIFICANCE: In this 12-week clinical study, all 0.454% SnF2 dentifrices delivered statistically significant reductions in the number of gingival bleeding sites relative to the negative control. Importantly, statistically significant efficacy differences were observed among the three 0.454% SnF2 dentifrices, demonstrating the important role that differences in formulation have on clinical efficacy.

The effects of bioavailable gluconate chelated stannous fluoride dentifrice on gingival bleeding: Meta-analysis of eighteen randomized controlled trials.

AIM: To estimate gingivitis effects of a bioavailable gluconate chelated 0.454% stannous fluoride (SnF2 ) family of dentifrices in adult subjects versus positive (triclosan) and negative (NaF or MFP) controls when used ≤3 months. MATERIALS AND METHODS: A meta-analysis evaluated bioavailable gluconate chelated SnF2 dentifrices versus a negative or positive control for gingival bleeding. RESULTS: In 18 randomized controlled trials (RCTs) with 2,890 subjects assessing SnF2 paste versus a negative or positive control, the average number of bleeding sites was reduced by 51% and 31%, respectively. The average change (95% CI) in number of bleeding sites was -16.3 (-27.8, -4.9) versus the negative control and -3.6 (-5.4, -1.8) versus the positive control. Subjects with localized or generalized gingivitis had 3.7 times better odds (95% CI [2.8, 5.0]) of shifting to generally healthy using SnF2 versus a negative control and 2.8 times better odds (95% CI [2.1, 3.9]) of shifting to generally healthy using SnF2 versus a positive control. The individual study risk of bias was deemed to be low in all categories of bias. CONCLUSION: This meta-analysis demonstrates significant gingivitis benefits of bioavailable SnF2 dentifrices when used ≤3 months versus positive (triclosan) and negative (NaF or MFP) controls.

Simultaneous voltammetric determination of guanine and adenine using MnO2 nanosheets and ionic liquid-functionalized graphene combined with a permeation-selective polydopamine membrane.

Guanine and adenine in blood samples can be detected by using an electrochemical sensor based on the use of manganese dioxide (MnO2) nanosheets and ionic liquid functionalized graphene (IL-GR) bound to a polydopamine (PDA) membrane. Both guanine and adenine undergo a redox reaction on the surface of the modified electrode. Cyclic voltammetry and differential pulse voltammetry were used to evaluate the electrochemical behavior of a glassy carbon electrode (GCE) modified with PDA/MnO2/IL-GR. The sensor allows for individual as well as simultaneous determination of guanine and adenine. The working voltage of differential pulse voltammetry at which data were acquired to establish the calibration plot: 0.6-1.2 V for guanine, 0.8-1.4 V for adenine, 0.4-1.4 V for mixture of guanine and adenine. A wide detection range (10-300 µM), low detection limits (guanine: 0.25 µM; adenine: 0.15 µM), selectivity and reproducibility are demonstrated. The modified GCE was successfully applied to the analysis of guanine and adenine in spiked fetal bovine serum and mouse whole blood samples. Graphical abstract An electrochemical sensor is presented for the determination of guanine (G) and adenine (A) based on MnO2 nanosheets, ionic liquid functionalized graphene (IL-graphene) and polydopamine membrane.

The erosion protection efficacy of a stabilized stannous fluoride dentifrice: An in situ randomized clinical trial.

PURPOSE: To compare the enamel protection efficacy of a stabilized stannous fluoride dentifrice to a triclosan-containing sodium fluoride dentifrice using a 10-day in situ erosion model, in accordance with the American Dental Association Seal of Acceptance guidelines for enamel erosion control. METHODS: In this single-center, double-blind, randomized, supervised-usage, two-treatment, four-period, crossover study, healthy adult subjects were randomized to a treatment sequence involving the following products: a 0.454% stannous fluoride (1,100 ppm F) dentifrice (Procter & Gamble) and a control dentifrice containing 0.243% sodium fluoride (1,100 ppm F) and 0.3% triclosan (Colgate-Palmolive). Each study period consisted of 10 treatment days. Subjects wore an intra-oral appliance fitted with two polished human enamel samples for 6 hours per treatment day. While wearing the appliance, subjects swished with their assigned dentifrice slurry for 60 seconds twice daily and with 250 ml orange juice over a 10-minute period four times daily. After 10 days, enamel specimens were removed and measured for surface loss using contact profilometry. RESULTS: 36 subjects were enrolled and 33 completed the study (mean age = 41.8 years). The stannous fluoride dentifrice demonstrated 90.3% less enamel loss than the NaF/triclosan dentifrice (P < 0.001) at Day 10, with median enamel loss of 0.279 µm and 2.877 µm, respectively. Both products were well tolerated. CLINICAL SIGNIFICANCE: The stannous fluoride dentifrice provided significantly greater protection against dental erosion relative to the NaF/triclosan dentifrice.

Seawater-driven forward osmosis for pre-concentrating nutrients in digested sludge centrate.

Seawater-driven forward osmosis to enrich nutrients from sludge centrate and reduce membrane fouling is demonstrated. Due to enrichment and pH increase in the feed solution, without appropriate control measure, nutrient precipitation can occur directly on the membrane surface causing severe membrane fouling and reducing nutrient enrichment efficiency. Indeed without agitating the feed, there was less precipitation on the membrane surface, compared to with agitation. In addition, increase in the membrane area over permeate volume ratio significantly reduced the filtration time and nutrient precipitation. A novel technique to maintain the draw solution (DS) at an acidic condition was developed to improve nutrient enrichment and reduce membrane fouling. By using this technique and a high membrane surface to permeate volume ratio, nutrient enrichment similar to the theoretical efficiency was successfully demonstrated. Our technique reduced the filtration time to achieve 70% water recovery by over 90% (compared to unbuffered seawater as the DS, small membrane area, and feed agitation), as a result of significantly less membrane fouling. The amount of phosphorus precipitate on the membrane surface decreased by more than 10 times. The enrichment of ammonia and phosphorus as a function of water recovery was similar to the theoretical calculation, indicating negligible nutrient loss due to precipitation.

Randomized in situ clinical trial evaluating erosion protection efficacy of a 0.454% stannous fluoride dentifrice.

OBJECTIVES: To assess the protective effects of a 0.454% stabilized stannous fluoride dentifrice and a marketed triclosan dentifrice against enamel erosion in a 10-day in situ model. METHODS: This was a double-blind, randomized, 2-treatment, 4-period, crossover in situ trial involving healthy adult participants. Participants were randomized to a treatment sequence involving the following products: a highly bioavailable 0.454% stannous fluoride dentifrice (Procter & Gamble) and a marketed dentifrice control containing 0.24% sodium fluoride and 0.3% triclosan (Colgate-Palmolive). Each study period took place over 10 days. Participants wore an intra-oral appliance retaining two polished human enamel samples for 6 hours per day. Two times per day they swished with the assigned dentifrice slurry and four times per day they swished with 250 mL of orange juice (25 mL per minute) over a 10-minute period. Contact profilometry measurements were made for each sample at baseline and day 10 to determine surface change. RESULTS: Thirty-six participants were enrolled and 33 completed the study (mean age = 40.5 years). The stannous fluoride dentifrice demonstrated 93.5% less enamel loss than the NaF/triclosan dentifrice (P < 0.001) at Day 10, with median enamel loss of 0.097 µm and 1.495 µm, respectively. Both products were well tolerated. CONCLUSION: The stannous fluoride dentifrice demonstrated significantly greater erosion protection efficacy relative to the NaF/triclosan dentifrice in this randomized in situ clinical trial.

Erosion protection efficacy of a 0.454% stannous fluoride dentifrice versus an arginine-containing dentifrice.

PURPOSE: To assess the anti-erosion effects of a 0.454% stannous fluoride dentifrice versus a marketed dentifrice in an in situ clinical study. METHODS: This was a double-blind, randomized and controlled, two-treatment, four-period crossover clinical study involving healthy adults. Each study period was 10 days. Subjects were randomized to one of two dentifrice products each period: an experimental 0.454% stannous fluoride dentifrice (1,100 ppm fluoride) or a marketed 1.5% arginine-containing dentifrice (Colgate Maximum Cavity Protection, 1,450 ppm fluoride). Subjects wore an intra-oral appliance fitted with two polished human enamel samples for 6 hours per day, swishing with the assigned dentifrice slurry twice a day in addition to sipping and swishing with 250 ml of orange juice for 10 minutes (in increments of 25 ml each minute) four times each day. Contact profilometry was used to measure surface loss of tooth enamel over the course of the study. Two measurements for each sample were taken at baseline and Day 10. RESULTS: 35 subjects were randomized to treatment and 31 completed the study (mean age = 40 years). At Day 10, enamel loss means were 0.128 µm for the stannous fluoride dentifrice and 1.377 µm for the arginine-containing dentifrice, respectively (P< 0.001). This represents 90.7% less enamel loss for the stannous fluoride dentifrice. Both products were well tolerated. CLINICAL SIGNIFICANCE: The 0.454% stannous fluoride dentifrice demonstrated significantly greater protection to human enamel against erosive acid challenges relative to the marketed 1.5% arginine-containing dentifrice in this in situ clinical study.

Penetration and bactericidal efficacy of two oral care products in an oral biofilm model.

PURPOSE: To investigate the immediate penetration and bactericidal effect of two oral care products marketed in China on an intact natural plaque biofilm model at different time points. METHODS: Eight subjects (aged 20 to 30 years; Turesky Plaque Index Score 2 to 3) were enrolled in the study according to the inclusion criteria. Plaque accumulators were worn by the subjects for 6 and 48 hours for harvesting the dental biofilm. Then the biofilms from different groups were stained with the LIVE/DEAD BacLight fluorescence system to investigate the changes in thickness and fluorescence intensity of living bacteria in biofilm 5 and 15 minutes post-treatment with a mouthrinse containing 0.074% cetylpyridinium chloride (1-minute treatment) or a toothpaste supernatant containing 1.16% stannous chloride (2-minute treatment). In addition, a specific Sn2+ probe was utilized to evaluate the penetration of Sn2+ in the biofilm. Fluorescent images were collected using confocal laser scanning microscopy. Analysis of covariance was used for statistical analyses. All comparisons were two-sided using a 5% level of significance. RESULTS: The thickness of generated plaque biofilm increased gradually from 7.352±4.22 µm at 6 hours to 16.73±7.38 µm at 48 hours (P< 0.05), whereas the thickness and fluorescence intensity of living bacteria stayed unchanged over time. After the treatment of toothpaste supernatant, the ratios of living bacteria thickness and fluorescence intensity of 6- and 48-hour plaque biofilm were significantly decreased (P< 0.05). Treatment of mouthrinse reduced the ratio of living bacteria thickness, but showed no significant impact on overall fluorescence intensity of living bacteria. For 48-hour biofilm, toothpaste supernatant significantly reduced fluorescence intensity of living bacteria from outer layer through inner layer, whereas the mouthrinse showed bactericidal effect only in the outer layer and middle layer. A wide distribution of Sn2+ was shown in the biofilm with the treatment of the tested toothpaste. CLINICAL SIGNIFICANCE: This biofilm model proved to be useful and appropriate for pre-clinical testing of anti-plaque agents. A brief exposure of the biofilm to the tested toothpaste produced significant losses in bacteria viability across outer-middle-inner layers. The tested mouthrinse exerted its bactericidal effect mostly in outer and middle layers of biofilm. The penetration of Sn2+ in the biofilm performed an important function in the bactericidal effect of the toothpaste.