Effect of Dentin Desensitizer Containing Novel Bioactive Glass on the Permeability of Dentin.

The objective of this study was to evaluate the effect of novel bioactive glass (BAG)-containing desensitizers on the permeability of dentin. Experimental dentin desensitizers containing 3 wt% BAG with or without acidic functional monomers (10-MDP or 4-META) were prepared. A commercial desensitizer, Seal & Protect (SNP), was used as a control. To evaluate the permeability of dentin, real-time dentinal fluid flow (DFF) rates were measured at four different time points (demineralized, immediately after desensitizer application, after two weeks in simulated body fluid (SBF), and post-ultrasonication). The DFF reduction rate (ΔDFF) was also calculated. The surface changes were analyzed using field emission scanning electron microscopy (FE-SEM). Raman spectroscopy was performed to analyze chemical changes on the dentin surface. The ΔDFF of the desensitizers containing BAG, BAG with 10-MDP, and BAG with 4-META significantly increased after two weeks of SBF storage and post-ultrasonication compared to the SNP at each time point (p < 0.05). Multiple precipitates were observed on the surfaces of the three BAG-containing desensitizers. Raman spectroscopy revealed hydroxyapatite (HAp) peaks on the dentin surfaces treated with the three BAG-containing desensitizers. Novel BAG-containing dentin desensitizers can reduce the DFF rate about 70.84 to 77.09% in the aspect of reduction of DFF through the HAp precipitations after two weeks of SBF storage.

Symbol-Level Selective Channel Estimation in Packet-Based OFDM Systems.

Wireless access in vehicular environments to support wireless communication between vehicles has been developed to provide road safety and infotainment services. In vehicular environments where the channel changes rapidly, channel estimation is very important in improving the reliability of wireless communication. Therefore, numerous channel estimation schemes have been proposed; however, none of the schemes proposed so far can perform well over the entire signal-to-noise ratio (SNR) region. In this paper, we propose a novel channel estimation scheme that selectively uses the better scheme between two channel estimation schemes on a symbol-by-symbol basis. The results show that the proposed scheme performs symbol-by-symbol selection of the better channel estimation scheme within a packet, and thus shows excellent performance over the entire SNR region in vehicular environments in terms of the bit error rate and packet error rate.

Preamble-Based Adaptive Channel Estimation for IEEE 802.11p.

Recently, research into autonomous driving and traffic safety has been drawing a great deal of attention. To realize autonomous driving and solve traffic safety problems, wireless access in vehicular environments (WAVE) technology has been developed, and IEEE 802.11p defines the physical (PHY) layer and medium access control (MAC) layer in the WAVE standard. However, the IEEE 802.11p frame structure, which has low pilot density, makes it difficult to predict the properties of wireless channels in a vehicular environment with high vehicle speeds; thus, the performance of the system is degraded in realistic vehicular environments. The motivation for this paper is to improve the channel estimation and tracking performance without changing the IEEE 802.11p frame structure. Therefore, we propose a channel estimation technique that can perform well over the entire SNR range of values by changing the method of channel estimation accordingly. The proposed scheme selectively uses two channel estimation schemes, each with outstanding performance for either high-SNR or low-SNR signals. To implement this, an adaptation algorithm based on a preamble is proposed. The preamble is a signal known to the transmitter-receiver, so that the receiver can obtain channel estimates without demapping errors, evaluating performance of the channel estimation schemes. Simulation results comparing the proposed method to other schemes demonstrate that the proposed scheme can selectively switch between the two schemes to improve overall performance.

Fabrication of conductive and printable nano carbon ink for wearable electronic and heating fabrics.

Printable Nano carbon colloidal ink has fascinated great attention due to their exceptional potential for large-scale application for powering wearable electronic devices. Though, it is challenging to incorporate various characteristics together such as mechanical stability, solution printability, conductivity, electrocatalytic activity, and heat generating properties in the flexible fabric based electrode system. In this research the development of printable composites made with woven/nonwoven fabrics printed with multiwall carbon nanotubes for flexible and wearable heating system and cathodes for dye-sensitized solar cells (DSSC), respectively. We report a printable carbon ink of multiwall carbon nanotubes (MWCNT) synthesized by globular protein serum bovine albumin (BSA). BSA is amino-rich dispersant used to disperse MWCNT and generate tubular porous carbon matrix. High loading ratio of BSA increases the dispersing power of MWCNT and increased porosity of CNT matrix. The proposed Organic Nanocarbon ink (Organic NC) serve the pathways for electron transport leading to higher heat dissipation as the well high conductivity and electrocatalytic activity. It was interesting to reveal that different kinds of woven and nonwoven fabrics displayed exceptional thermal properties when DC voltage was applied. The heat generating properties were highly dependent on the type of fabric and conductive ink uptake. Our proposed Organic NC printed fabric system exhibited superior conductivity with 15-20â€¯Ω resistivity and lower charge transfer resistance RCT = 2.69 Ω, demonstrated an 8% power conversion efficiency of DSSC. The proposed research paves the ways for solution printable high performance woven and nonwoven conductive and thermoelectric materials for wearable electronics.

Virtual Simulation of Autotransplantation Using 3-dimensional Printing Prototyping Model and Computer-assisted Design Program.

This case report describes an innovative virtual simulation method using a computer-aided rapid prototyping (CARP) model and a computer-aided design (CAD) program for autotransplantation of an immature third molar.A compromised left mandibular second molar (#18) was extracted and replaced by autotransplantation using an immature left mandibular third molar (#17). In order to minimize the surgical time and injury to the donor tooth, a virtual 3-dimensional (3D) rehearsal surgery was planned. Cone-beam computed tomographic images were taken to fabricate the 3D printing CARP model of the donor tooth and tentative extraction socket. Subsequently, both CARP models were scanned with an intraoral scanner (CEREC Omnicam; Dentsply Sirona, Bensheim, Germany) followed by superimposition and virtual simulation of osteotomy preparation of the recipient alveolus using the CAD analysis program. During the surgery, the extraction socket was precisely prepared according to the predetermined location and dimensions via virtual simulation rehearsal surgery using CAD analysis. The donor tooth was atraumatically transplanted into the prepared socket. The follow-up examination revealed that the root developed with a normal periodontal ligament and lamina dura.Virtual simulation using a 3D printing CARP model and a CAD program could be clinically useful in autotransplantation of an immature third molar by ensuring an atraumatic and predictable surgery.

The multivariate detection limit for Mycoplasma pneumoniae as determined by nanorod array-surface enhanced Raman spectroscopy and comparison with limit of detection by qPCR.

Mycoplasma pneumoniae is a cell wall-less bacterial pathogen of the human respiratory tract that accounts for up to 20% of community-acquired pneumonia. At present, the standard for detection and genotyping is quantitative polymerase chain reaction (qPCR), which can exhibit excellent sensitivity but lacks standardization and has limited practicality for widespread, point-of-care use. We previously described a Ag nanorod array-surface enhanced Raman spectroscopy (NA-SERS) biosensing platform capable of detecting M. pneumoniae in simulated and true clinical throat swab samples with statistically significant specificity and sensitivity. We report here that differences in sample preparation influence the integrity of mycoplasma cells for NA-SERS analysis, which in turn impacts the resulting spectra. We have established a multivariate detection limit (MDL) using NA-SERS for M. pneumoniae intact-cell sample preparations. Using an adaptation of International Union of Pure and Applied Chemistry (IUPAC)-recommended methods for analyzing multivariate data sets, we found that qPCR had roughly 10× better detection limits than NA-SERS when expressed in CFU ml(-1) and DNA concentration (fg). However, the NA-SERS MDL for intact M. pneumoniae was 5.3 ± 1.0 genome equivalents (cells per µl). By comparison, qPCR of a parallel set of samples yielded a limit of detection of 2.5 ± 0.25 cells per µl. Therefore, for certain standard metrics NA-SERS provides a multivariate detection limit for M. pneumoniae that is essentially identical to that determined via qPCR.

Identification of virulence determinants in influenza viruses.

To date there is no rapid method to screen for highly pathogenic avian influenza strains that may be indicators of future pandemics. We report here the first development of an oligonucleotide-based spectroscopic assay to rapidly and sensitively detect a N66S mutation in the gene coding for the PB1-F2 protein associated with increased virulence in highly pathogenic pandemic influenza viruses. 5'-Thiolated ssDNA oligonucleotides were employed as probes to capture RNA isolated from six influenza viruses, three having N66S mutations, two without the N66S mutation, and one deletion mutant not encoding the PB1-F2 protein. Hybridization was detected without amplification or labeling using the intrinsic surfaced-enhanced Raman spectrum of the DNA-RNA complex. Multivariate analysis identified target RNA binding from noncomplementary sequences with 100% sensitivity, 100% selectivity, and 100% correct classification in the test data set. These results establish that optical-based diagnostic methods are able to directly identify diagnostic indicators of virulence linked to highly pathogenic pandemic influenza viruses without amplification or labeling.

A flexible amorphous Bi(5)Nb(3)O(15) film for the gate insulator of the low-voltage operating pentacene thin-film transistor fabricated at room temperature.

The amorphous Bi(5)Nb(3)O(15) film grown at room temperature under an oxygen-plasma sputtering ambient (BNRT-O(2) film) has a hydrophobic surface with a surface energy of 35.6 mJ m(-2), which is close to that of the orthorhombic pentacene (38 mJ m(-2)), resulting in the formation of a good pentacene layer without the introduction of an additional polymer layer. This film was very flexible, maintaining a high capacitance of 145 nF cm(-2) during and after 10(5) bending cycles with a small curvature radius of 7.5 mm. This film was optically transparent. Furthermore, the flexible, pentacene-based, organic thin-film transistors (OTFTs) fabricated on the poly(ether sulfone) substrate at room temperature using a BNRT-O(2) film as a gate insulator exhibited a promising device performance with a high field effect mobility of 0.5 cm(2) V(-1) s(-1), an on/off current modulation of 10(5), and a small subthreshold slope of 0.2 V decade(-1) under a low operating voltage of -5 V. This device also maintained a high carrier mobility of 0.45 cm(2) V(-1 )s(-1) during the bending with a small curvature radius of 9 mm. Therefore, the BNRT-O(2) film is considered a promising material for the gate insulator of the flexible, pentacene-based OTFT.

Regulatory interaction between CFTR and the SLC26 transporters.

Most epithelia that express CFTR secrete fluid rich in HCO3- and poor in Cl- that is generated by a CFTR-dependent Cl- absorption and HCO3- secretion process that when aberrant leads to human diseases such as cystic fibrosis and congenital chloride diarrhoea. Epithelial Cl- absorption and HCO3- secretion require expression of CFTR and other Cl- and HCO3- transporters in the luminal membrane of the secreting cells. Recent advances in understanding this critical epithelial function revealed that the luminal Cl- and HCO3- transporters are members of the SLC26 family. Characterization of several members of the family reveals that all characterized thus far are electrogenic with an isoform specific Cl-/HCO3- transport stoichiometry. In vivo these transporters exist in a transporting complex with CFTR. The SLC26 transporters and CFTR are recruited to the complex by binding to scaffolds containing PDZ domains. Upon stimulation and PKA-dependent phosphorylation of CFTR R domain, the R domain binds to the SLC26 transporter STAS domain. Interaction of the R and STAS domains results in a marked and mutual activation of CFTR and the SLC26 transporters. The significance of this mode of regulation to epithelial Cl- absorption and HCO3- secretion is obvious.

A molecular mechanism for aberrant CFTR-dependent HCO(3)(-) transport in cystic fibrosis.

Aberrant HCO(3)(-) transport is a hallmark of cystic fibrosis (CF) and is associated with aberrant Cl(-)-dependent HCO(3)(-) transport by the cystic fibrosis transmembrane conductance regulator (CFTR). We show here that HCO(3)(-) current by CFTR cannot account for CFTR-activated HCO(3)(-) transport and that CFTR does not activate AE1-AE4. In contrast, CFTR markedly activates Cl(-) and OH(-)/HCO(3)(-) transport by members of the SLC26 family DRA, SLC26A6 and pendrin. Most notably, the SLC26s are electrogenic transporters with isoform-specific stoichiometries. DRA activity occurred at a Cl(-)/HCO(3)(-) ratio > or =2. SLC26A6 activity is voltage regulated and occurred at HCO(3)(-)/Cl(-) > or =2. The physiological significance of these findings is demonstrated by interaction of CFTR and DRA in the mouse pancreas and an altered activation of DRA by the R117H and G551D mutants of CFTR. These findings provide a molecular mechanism for epithelial HCO(3)(-) transport (one SLC26 transporter-electrogenic transport; two SLC26 transporters with opposite stoichiometry in the same membrane domain-electroneutral transport), the CF-associated aberrant HCO(3)(-) transport, and reveal a new function of CFTR with clinical implications for CF and congenital chloride diarrhea.

The cystic fibrosis transmembrane conductance regulator interacts with and regulates the activity of the HCO3- salvage transporter human Na+-HCO3- cotransport isoform 3.

Cystic fibrosis transmembrane conductance regulator (CFTR) regulates both HCO(3)(-) secretion and HCO(3)(-) salvage in secretory epithelia. At least two luminal transporters mediate HCO(3)(-) salvage, the Na(+)/H(+) exchanger (NHE3) and the Na(+)-HCO(3)(-) cotransport (NBC3). In a previous work, we show that CFTR interacts with NHE3 to regulate its activity (Ahn, W., Kim, K. W., Lee, J. A., Kim, J. Y., Choi, J. Y., Moe, O. M., Milgram, S. L., Muallem, S., and Lee, M. G. (2001) J. Biol. Chem. 276, 17236-17243). In this work, we report that transient or stable expression of human NBC3 (hNBC3) in HEK cells resulted in a Na(+)-dependent, DIDS (4,4'-diisothiocyanostilbene-2,2'-disulfonic acid)- and 5-ethylisopropylamiloride-insensitive HCO(3)(-) transport. Stimulation of CFTR with forskolin markedly inhibited NBC3 activity. This inhibition was prevented by the inhibition of protein kinase A. NBC3 and CFTR could be reciprocally coimmunoprecipitated from transfected HEK cells and from the native pancreas and submandibular and parotid glands. Precipitation of NBC3 or CFTR from transfected HEK293 cells and from the pancreas and submandibular gland also coimmunoprecipitated EBP50. Glutathione S-transferase-EBP50 pulled down CFTR and hNBC3 from cell lysates when expressed individually and as a complex when expressed together. Notably, the deletion of the C-terminal PDZ binding motifs of CFTR or hNBC3 prevented coimmunoprecipitation of the proteins and inhibition of hNBC3 activity by CFTR. We conclude that CFTR and NBC3 reside in the same HCO(3)(-)-transporting complex with the aid of PDZ domain-containing scaffolds, and this interaction is essential for regulation of NBC3 activity by CFTR. Furthermore, these findings add additional evidence for the suggestion that CFTR regulates the overall trans-cellular HCO(3)(-) transport by regulating the activity of all luminal HCO(3)(-) secretion and salvage mechanisms of secretory epithelial cells.

AE4 is a DIDS-sensitive Cl(-)/HCO(-)(3) exchanger in the basolateral membrane of the renal CCD and the SMG duct.

The renal cortical collecting duct (CCD) plays an important role in systemic acid-base homeostasis. The beta-intercalated cells secrete most of the HCO(-)(3), which is mediated by a luminal, DIDS-insensitive, Cl(-)/HCO(-)(3) exchange. The identity of the luminal exchanger is a matter of debate. Anion exchanger isoform 4 (AE4) cloned from the rabbit kidney was proposed to perform this function (Tsuganezawa H et al. J Biol Chem 276: 8180-8189, 2001). By contrast, it was proposed (Royaux IE et al. Proc Natl Acad Sci USA 98: 4221-4226, 2001) that pendrin accomplishes this function in the mouse CCD. In the present work, we cloned, localized, and characterized the function of the rat AE4. Northern blot and RT-PCR showed high levels of AE4 mRNA in the CCD. Expression in HEK-293 and LLC-PK(1) cells showed that AE4 is targeted to the plasma membrane. Measurement of intracellular pH (pH(i)) revealed that AE4 indeed functions as a Cl(-)/HCO(-)(3) exchanger. However, AE4 activity was inhibited by DIDS. Immunolocalization revealed species-specific expression of AE4. In the rat and mouse CCD and the mouse SMG duct AE4 was in the basolateral membrane. By contrast, in the rabbit, AE4 was in the luminal and lateral membranes. In both, the rat and rabbit CCD AE4 was in alpha-intercalated cells. Importantly, localization of AE4 was not affected by the systemic acid-base status of the rats. Therefore, we conclude that expression and possibly function of AE4 is species specific. In the rat and mouse AE4 functions as a Cl(-)/HCO(-)(3) exchanger in the basolateral membrane of alpha-intercalated cells and may participate in HCO(-)(3) absorption. In the rabbit AE4 may contribute to HCO(-)(3) secretion.