Enhancing the signal contrast ratio and stability of liquid crystal-based sensors by using fine grids made by photolithography of photoresists.

We prepared fine grid patterns on a glass substrate through photolithography of photoresists; we filled photoresist grids with liquid crystals (LCs) to construct LC-based sensors. Scanning electron microscopy images revealed that the photoresist grids were flat, smooth, and 3.0-8.0 µm thick. In contrast to conventional LC-based sensors, in which LCs are filled in metal grids placed on glass substrates, our results proved that LC-based sensors constructed using photoresist grids exhibited a larger signal contrast ratio, better signal stability in aqueous solutions and lower limit of detection for mercuric ions. All these characteristics enhanced the performance of the LC-based sensors.

Differences in Fatty Acid Oxidation between Nab-Paclitaxel- and Solvent-Based Paclitaxel-Treated A549 Cells Based on Metabolomics.

The pharmacokinetics, safety, and anticancer efficacy profiles of nanoparticle albumin-bound (nab)-paclitaxel formulations are superior to those of solvent-based paclitaxel formulations. The aims of the present study were to study the effects of nab-paclitaxel and solvent-based paclitaxel formulations on the metabolic profiles of the model cell line (A549) and attempt to elucidate the associated metabolic pathways. A mass spectrometry-based cell metabolomics approach and viability evaluation were used to explore the potential difference. Western blotting was utilized to measure the levels of relevant proteins, and carnitine palmitoyltransferase 1 (CPT1) activities were quantified. Fold changes normalized to controls in levels of carnitine and several acylcarnitines were significantly different (p < 0.05) between A549 cells treated with nab-paclitaxel and those treated with solvent-based paclitaxel. Relative to the controls, there were also significant fold change differences in palmitic and linoleic acid levels in the cell lysates, mitochondrial CPT1 activities, and mitochondrial medium-chain acyl-CoA dehydrogenase (MCAD) protein levels in the A549 cells subjected to the nab-paclitaxel and solvent-based paclitaxel formulations. Results suggested that the two formulations differentially modulated fatty acid oxidation in the A549 cells. While cell viability results did not reveal significant differences, the findings implied that a mass spectrometry-based cell metabolomics approach could be a sensitive tool to explore the differences caused by formulation changes without using animals. Since uncertainties of products containing nanomaterials warrant holistic screening to address safety concerns, the aforementioned approach may be of regulatory importance and is worth further investigation.

Cell metabolomics analyses revealed a role of altered fatty acid oxidation in neurotoxicity pattern difference between nab-paclitaxel and solvent-based paclitaxel.

Peripheral neuropathy (PN) is a dose-limiting, painful adverse reaction associated with the use of paclitaxel. This common side effect was often partially attributed to the solvent used for solubilization of the highly hydrophobic drug substance. Therefore, the development of alternative formulations thrived, which included that of Abraxane® containing nanoparticle albumin-bound paclitaxel (nab-paclitaxel). However, studies demonstrated inconsistent conclusions regarding the mitigation of PN in comparison with the traditional formulation. The mass spectrometry-based cell metabolomics approach was used in the present study to explore the potentially associated mechanisms. Although no significant difference in the effects on cell viability was observed, fold changes in carnitine, several acylcarnitines and long-chain fatty acid(s) were significantly different between treatment groups in differentiated and undifferentiated SH-SY5Y cells. The most prominent difference observed was the significant increase of octanoylcarnitine in cells treated with solvent-based paclitaxel, which was found to be associated with significant decrease of medium-chain acyl-CoA dehydrogenase (MCAD). The findings suggested the potential role of altered fatty acid oxidation in the different neurotoxicity patterns observed, which may be a possible target for therapeutic interventions worth further investigation.

Using Diazotization Reaction to Develop Portable Liquid-Crystal-Based Sensors for Nitrite Detection.

A liquid-crystal (LC)-based sensor for detecting nitrite in aqueous solutions was developed using a diazotization reaction as the sensing mechanism. First, tetradecyl 4-aminobenzoate (14CBA) was synthesized and doped into a nematic LC, i.e., 4-cyano-4'-pentylbiphenyl (5CB). When the LC mixture was cast on a glass substrate and then immersed into an aqueous solution without nitrite, the orientation of LC was planar and the LC image was bright. In the presence of nitrite, it reacted with alkylanilines to give corresponding diazonium ions with a positive charge, which aligned at the LC/aqueous interface to cause homeotropic orientation of LC. As a result, a bright-to-dark transition of the LC image was observed. The limit of detection (LOD) of this system for nitrite is 25 µM with high selectivity. In addition, this system can work in environmental water samples such as tap water and pond water. Finally, we demonstrated that the optical signals of LC can be measured and recorded using a built-in digital camera of a smartphone, suggesting the portability of this system for on-site applications.

Quantitative analysis of liquid crystal-based immunoassay using rectangular capillaries as sensing platform.

In past studies, liquid crystal (LC)-based immunoassays were accomplished by fabricating an LC cell with two pieces of glass slides after immunobinding, which makes the determination of the immunoassay not in real-time and requires trained personnel. Herein, we developed the LC-based immunoassay by using rectangular capillaries as the substrate for immunobinding. The inner surface of rectangular capillaries was decorated with a long alkyl saline, dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (DMOAP), followed by immobilization of human serum albumin (HSA) as the probe. In this situation, the orientation of LC was homeotropic and dark LC image was observed under polarized light. When the solution containing anti-human serum albumin (anti-HSA) were dispensed into the capillary through capillary action, the specific immunobinding between HSA and anti-HSA formed an immunocomplex on the inner surface of capillary, which disrupted the original orientation of LC and led to a dark-to-bright transition of the LC images. The quantification of anti-HSA can be achieved by measuring the length of the bright LC image in the rectangular capillary. By using this immunoassay, the limit of detection (LOD) for anti-HSA is 1 µg/mL, and it did not respond to HSA and anti-human immunoglobulin G (anti-h-IgG). On the other hand, the diversity of the LC-based immunoassay can be extended for HSA detection when we immobilized anti-HSA in the capillary. Because the post-fabrication of LC cell was waived by using rectangular capillaries to develop the LC-based immunoassay, it is more convenient for users to handle and collect more reliable data. Moreover, the results of the immunoassay were visualized through naked-eye and could be recorded by a smartphone; it is more suitable for portable and point-of-care applications.

Association between Arsenic Exposure and Diabetes: A Meta-Analysis.

Studies on the association between arsenic exposure and diabetes mellitus (DM) yielded inconsistent results. Epidemiologic data on the associations between arsenic exposures via inhalation and DM are limited. Therefore, we conducted a meta-analysis to evaluate the risk of DM associated with arsenic exposure. We searched the related literature through a systematic approach and analyzed the data according to the exposure route (inhalation and ingestion). We used random-effect models to estimate the summary relative risks (RRs) for DM associated with arsenic exposure and used I (2) statistics to assess the heterogeneity of studies. We identified 38 relevant studies, of which the 32 on the ingestion route showed a significant association between arsenic exposure and DM (RR = 1.57; 95% CI 1.27-1.93). Focusing on the 24 studies in which the diagnosis of DM was confirmed using laboratory tests or medical records, we found that the summary RR was 1.71 (95% CI 1.32-2.23), very close to the overall estimates. We concluded that ingested arsenic is associated with the development of DM, but the heterogeneity among the studies may affect the results.

Association between arsenic exposure and diabetes mellitus in Cambodia.

Whereas studies in Taiwan found associations between arsenic exposure from drinking water and diabetes mellitus (DM), studies in other countries yielded inconsistent results, and diet might be a confounder. We conducted a study in Cambodia, where people have non-Western style diet, to evaluate the association. We measured well water and urine samples and examined skin signs of arsenicosis to assess arsenic exposure and used questionnaires to collect data on potential risk factors. We performed a fingertip blood glucose test followed by measurement of hemoglobin A1c to assess DM. The 43-male and 99-female participants had an average age of 40.4 years. We found that participants with skin signs of arsenicosis had a higher level of arsenic in the drinking water (1101.1 versus 972.2 µ g/L, P = 0.02). Drinking water with arsenic levels above the median (907.25 µ g/L) was associated with a nearly twofold increase in the risk of DM (odds ratio [OR] = 1.7, 95% confidence interval [CI]: 0.5-5.8), so was having skin sings of arsenicosis (OR = 1.7, 95% CI: 0.5-5.6). The ORs did not reach statistical significance most likely because of the small case number. Therefore, further studies with larger study populations are needed to confirm our findings.

Optimizing anterior esthetics of a single-tooth implant through socket augmentation and immediate provisionalization: a case report with 7-year follow-up.

Tooth extraction inevitably accompanies alveolar ridge resorption with loss of pre-existing tissue morphology. Replacing missing teeth with dental implants has become popular, but restoring anterior teeth with implant-supported restorations is a technique-sensitive task and poses challenges for dentists. With the progress of implant dentistry, the demand for optimal esthetics has become linked with the desire for faster, easier techniques that shorten treatment time and also satisfy patients. Immediate provisionalization of a single-tooth implant provides significant benefits compared with traditional delayed protocols, such as aiding the contouring of peri-implant soft tissue and enhancing patient comfort and satisfaction. This article describes a meticulous approach to a hopeless maxillary central incisor with root fracture. The defect in the extraction socket was reconstructed using autogenous bone harvested from the chin. Four months later, an implant was installed and immediately restored. After another healing period of 6 months, the peri-implant soft tissue had been shaped and matured according to the contours of the provisional restoration. The emergence profile was used to duplicate the definitive restoration. Peri-implant esthetics was achieved through socket augmentation and immediate provisionalization of the implant. This treatment modality attained predictable and maintainable outcomes, both functionally and esthetically.

Using a spectrophotometric study of human gingival colour distribution to develop a shade guide.

OBJECTIVES: For dental prostheses, colour choice is a main concern. The present spectrometric study analyzes healthy gingiva to develop a shade guide for pink aesthetics. METHODS: A reflectance spectrometer and an external light source were set up in a 45/0-degree optical configuration to measure the colour of gingiva over the maxillary anterior area. A total of 362 human subjects with healthy gingiva were divided into groups according to sex and age. The Commission Internationale de l'Eclairage L*, a*, and b* (CIELAB) values and differences in colour (ΔE) were measured. A two-way analysis of variance (ANOVA) test and cluster analyses were used to analyse the data. RESULTS: There are significant differences in the gingival colour by sex (ΔE > 3.7). The mean CIE L* value of female gingiva is significantly higher than that of male gingiva (p < 0.05). No significant differences were found between age groups. 10 categories for gingival colour are established. CONCLUSION: The gingival colour of females is lighter than that of males. The proposed colour classification can be used as a gingival shade guide reference by dental laboratory technicians.