Development of peptide biosensor for the detection of dengue fever biomarker, nonstructural 1.

Dengue virus (DENV) nonstructural 1 (NS1) protein is a specific and sensitive biomarker for the diagnosis of dengue. In this study, an efficient electrochemical biosensor that uses chemically modified affinity peptides was developed for the detection of dengue virus NS1. A series of amino acid-substituted synthetic peptides was rationally designed, chemically synthesized and covalently immobilized to a gold sensor surface. The sensor performance was monitored via square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS). Potential affinity peptides specific for NS1 were chosen according to the dynamic current decrease in SWV experiments. Using circular dichroism, the molar ellipticity of peptides (DGV BP1-BP5) was determined, indicating that they had a mostly similar in random coil structure, not totally identical. Using SWV, DGV BP1 was selected as a promising recognition peptide and limit of detection for NS1 was found to be 1.49 µg/mL by the 3-sigma rule. DGV BP1 showed good specificity and stability for NS1, with low signal interference. The validation of the sensor to detect NS1 proteins was confirmed with four dengue virus culture broth (from serotype 1 to 4) as proof-of-concept. The detection performance of our sensor incorporating DGV BP1 peptides showed a statistically significant difference. These results indicate that this strategy can potentially be used to detect the dengue virus antigen, NS1, and to diagnosis dengue fever within a miniaturized portable device in point-of-care testing.

Gold-copper nanoshell dot-blot immunoassay for naked-eye sensitive detection of tuberculosis specific CFP-10 antigen.

Herein, a straightforward and highly specific dot-blot immunoassay was successfully developed for the detection of Mycobacterium tuberculosis antigen (10 kDa culture filtrate protein, CFP-10) via the formation of copper nanoshell on the gold nanoparticles (AuNPs) surface. The principle of dot-blot immunoassay was based on the reduction of Cu2+ ion on the GBP-CFP10G2-AuNPs conjugates, which has gold binding and antigen binding affinities, simultaneously, favouring to appear red dot that can be observed with naked-eye. The dot intensity is proportional to the concentration of tuberculosis antigen CFP-10, which offers a detection limit of 7.6 pg/mL. The analytical performance of GBP-CFP10G2-AuNPs-copper nanoshell dot-blot was superior than that of conventional silver nanoshell. This method was successfully applied to identify the CFP-10 antigen in the clinical urine sample with high sensitivity, specificity, and minimized sample preparation steps. This method exhibits great application potential in the field of nanomedical science for highly reliable point-of-care detection of CFP-10 antigen in real samples to early diagnosis of tuberculosis.

Rapid discriminative detection of dengue viruses via loop mediated isothermal amplification.

Dengue virus (DENV) is one of the life-threatening viruses to the human. In this study, we have designed specific novel primers for rapid discriminative detection of DENV-1, DENV-2, and DENV-4 by real-time reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction. The effect of parameters such as reaction temperature and magnesium sulfate was investigated on the RT-LAMP reaction for detection of DENV RNA. Under the optimal conditions, this method is able to differentiate and to detect DENV within 25 min, exhibiting detection limit of 3.5 copies/µL. Importantly, the novel specific primers-based RT-LAMP assay did not react with other viruses, suggesting the selectivity of the method towards DENV RNA. The RT-LAMP reaction products are easily visualized with naked-eye when irradiated them under UV light at 365 nm. Amplification products could be visualized directly for color changes. This method provides a facile, and accurate molecular amplication technique for the rapid discriminative detection of dengue viruses. The RT-LAMP platform can be used as a promissing diagnostic tool for discriminative detection of DENV without aid of complicated protocols or sophisticated equipment.

A Cobalt Tandem Catalyst Supported on a Compressible Microporous Polymer Monolith.

A compressible microporous polymer monolith (MPM) was prepared by performing the Sonogashira-Hagihara reaction between 1,4-diiodobenzene and 1,3,5-triethynylbenzene in a gel state without stirring. MPM was functionalized via the click reaction with 1,3,5-tris(azidomethyl)-2,4,6-trimethylbenzene and 2,6-diethynylpyridine. MPM showed superhydrophobicity but became hydrophilic after the click reaction. The functionalized MPM (F-MPM) had polar triazole groups generated by the click reaction, which were used as coordination sites for Co(II) ions. Cobalt nanoparticles were loaded to F-MPM through in situ reduction of coordinated Co(II) ions to produce a monolithic Co heterogeneous catalyst (Co-MPM). The microscopic study showed that MPM, F-MPM, and Co-MPM consisted of fiber bundles, together with spherical particles on the micrometer scale. Co-MPM was used for tandem catalysis. Co-MPM promoted the reaction of dehydrogenation of ammonia borane and hydrogenation of nitro compounds in one pot to give amine products. The reactions with the compression and release process were much faster compared with the reactions performed under the stirring conditions, suggesting that the repeated compression and release facilitated interfacial contact between the reactants and active sites in Co-MPM.

Fabrication of a conjugated microporous polymer membrane and its application for membrane catalysis.

A flexible and free standing conjugated microporous polymer (CMP) membrane was prepared using a polyvinylpyrrolidone (PVP) electrospun membrane as a template. The PVP nanofibers of the template membrane were coated with a thin layer of the CMP through the in situ Sonogashira-Hagihara coupling reaction of 1,3,5-triethynylbenzene and 1,4-diiodobenzene. The PVP nanofibers were removed by the solvent extraction to produce the CMP membrane, which retained the entangled fibrous structure of the template membrane. Each fiber showed a hollow tubular structure having a CMP wall with a thickness of tens of nanometers. The microporous polymer membrane exhibited a high BET surface area with hierarchical porosity and good permeability. As a catalytic CMP membrane, the Ag nanoparticle-immobilized microporous polymer membrane was fabricated using an electrospun PVP@Ag membrane as a template. After being coated with the CMP, the PVP nanofibers were removed by the solvent extraction, but the Ag nanoparticles were trapped in the microporous polymer shell. The catalytic CMP membrane was successfully used for the catalytic reduction reaction of 4-nitrophenol. The hollow tubular structure and hierarchical porosity of the membrane allowed for the reactants to easily penetrate into the CMP wall and to contact the Ag nanoparticles, resulting in the high catalytic activity.

Preparation of a Sulfur-Functionalized Microporous Polymer Sponge and In Situ Growth of Silver Nanoparticles: A Compressible Monolithic Catalyst.

We report a compressible monolithic catalyst based on a microporous organic polymer (MOP) sponge. The monolithic MOP sponge was synthesized via Sonogashira-Hagihara coupling reaction between 1,4-diiodotetrafluorobenzene and 1,3,5-triethynylbenzene in a cosolvent of toluene and TEA (2:1, v/v) without stirring. The MOP sponge had an intriguing microstructure, where tubular polymer fibers having a diameter of hundreds of nanometers were entangled. It showed hierarchical porosity with a Brunauer-Emmett-Teller (BET) surface area of 512 m2 g-1. The MOP sponge was functionalized with sulfur groups by the thiol-yne reaction. The functionalized MOP sponge exhibited a higher BET surface area than the MOP sponge by 13% due to the increase in the total pore and micropore volumes. A MOP sponge-Ag heterogeneous catalyst (S-MOPS-Ag) was prepared by in situ growth of silver nanoparticles inside the sulfur-functionalized MOP sponge by the reduction of Ag+ ions. The catalytic activity of S-MOPS-Ag was investigated for the reduction reaction of 4-nitrophenol in an aqueous condition. When S-MOPS-Ag was compressed and released during the reaction, the rate of the reaction was considerably increased. S-MOPS-Ag was easily removed from the reaction mixture owing to its monolithic character and was reused after washing and drying.

Analysis of Vertical Ground Reaction Force Variables Using Foot Scans in Hemiplegic Patients.

OBJECTIVE: To analyze the differences in the vertical ground reaction force (GRF) variables of hemiplegic patients compared with a control group, and between the affected and unaffected limbs of hemiplegic patients using foot scans. METHODS: Patients (n=20) with hemiplegia and healthy volunteers (n=20) underwent vertical force analysis. We measured the following: the first and second peak forces (F1, F2) and the percent stances at which they occurred (T1, T2); the vertical force impulse (VFI) and stance times. The GRF results were compared between the hemiplegic patients and control individuals, and between the affected and unaffected limbs of hemiplegic patients. Additionally, we analyzed the impulse of the unaffected limb according to the motor assessment scale (MAS), Brunnstrom stage, and a Timed Up and Go Test. RESULTS: The F1s and F2s of the affected and unaffected limbs were significantly less than those of the normal control individuals (p<0.05). The T1s of both the affected and unaffected limbs of the patients were greater than control individuals, whilst the T2s were lower (p<0.05). Greater impulses and stance times were recorded on both sides of the patients than in the limbs of the control individuals (p<0.05). The MAS, Brunnstrom stage and Timed Up and Go Test results were significantly correlated with the VFI of the unaffected limbs (p<0.05). CONCLUSION: The high impulse values of the unaffected limb were associated with complications during gait rehabilitation. Therefore, these results suggest that unaffected limbs should also be taken into consideration in these patients.

Changes in Activation of Abdominal Muscles at Selected Angles During Trunk Exercise by Using Ultrasonography.

OBJECTIVE: To investigate the changes of activation of the abdominal muscles depending on exercise angles and whether the activation of rectus abdominis differs according to the location, during curl up and leg raise exercises, by measuring the thickness ratio of abdominal muscles using ultrasonography. METHODS: We examined 30 normal adults without musculoskeletal problems. Muscle thickness was measured in the upper rectus abdominis (URA), lower rectus abdominis (LRA), obliquus externus (EO), obliquus internus (IO), and transversus abdominis (TrA), at pre-determined angles (30°, 60°, 90°) and additionally at the resting angle (0°). Muscle thickness ratio was calculated by dividing the resting (0°) thickness for each angle, and was used as reflection of muscle activity. RESULTS: The muscle thickness ratio was significantly different depending on the angles in URA and LRA. For curl up-URA p=0 (30°<60°), p=0 (60°>90°), p=0.44 (30°<90°) and LRA p=0.01 (30°<60°), p=0 (60°>90°), p=0.44 (30°>90°), respectively, by one-way ANOVA test-and for leg raise-URA p=0 (30°<60°), p=0 (60°<90°), p=0 (30°<90°) and LRA p=0.01 (30°<60°), p=0 (60°<90°), p=0 (30°<90°), respectively, by one-way ANOVA test-exercises, but not in the lateral abdominal muscles (EO, IO, and TrA). Also, there was no significant difference in the muscle thickness ratio of URA and LRA during both exercises. In the aspect of muscle activity, there was significant difference in the activation of RA muscle by selected angles, but not according to location during both exercises. CONCLUSION: According to this study, exercise angle is thought to be an important contributing factor for strengthening of RA muscle; however, both the exercises are thought to have no property of strengthening RA muscle selectively based on the location.

Ultrasonographic measurement of transverse abdominis in stroke patients.

OBJECTIVE: To compare transverse abdominis (TrA) contractility in stroke patients with hemiparesis and healthy adults using musculoskeletal ultrasonography. METHODS: Forty-seven stroke patients with hemiparesis and 25 age-matched healthy control subjects participated in this study. Stroke patients were divided into three groups on the basis of their degree of ambulation. Group A consisted of 9 patients with wheelchair ambulation, group B of 23 patients with assisted ambulation, and group C of 15 patients with independent ambulation. Inter-rater reliability regarding ultrasonographic measurement of abdominal muscle thickness in the control group was assessed by two examiners. The TrA contraction ratio (TrA contracted thickness/TrA resting thickness) was measured during abdominal drawing-in maneuver and was compared between the patients and the control group and between the ambulation groups. RESULTS: The inter-rater reliability ranged from 0.900 to 0.947. The TrA contraction ratio was higher in the non-paretic side than in the paretic side (1.40±0.62 vs. 1.14±0.35, p<0.01). The TrA contraction ratio of the patient group was lower in the non-paretic side as well as in the paretic side than that of the control group (right 1.85±0.29, left 1.92±0.42; p<0.001). No difference was found between the ambulation regarding the TrA contraction ratio. CONCLUSION: The TrA contractility in hemiparetic stroke patients is significantly decreased in the non-paretic side as well as in the paretic side compared with that of healthy adults. Ultrasonographic measurement can be clinically used in the evaluation of deep abdominal muscles in stroke patients.

Stimulating effects of quercetin and phenamil on differentiation of human dental pulp cells.

Dentin formation is preferred in the healing response of the pulp to pulp-capping agents during vital pulp therapy. Enhancement of the dentinogenic differentiation of dental pulp cells is thought to accelerate pulp repair. The aim of this study was to evaluate the dentinogenic activity of small molecules (three flavonoids and phenamil) that have been shown previously to induce osteoblast differentiation. Among the flavonoids (quercetin, genistein and baicalin), quercetin induced the highest alkaline phosphatase (ALP) activity of human dental pulp (HDP) cells. Phenamil, an amiloride derivative, elicited higher ALP activity than quercetin. However, increased expression of dentin sialophosphoprotein (DSPP) mRNA and mineral deposition were seen in cultures treated with quercetin compared with phenamil. This would seem to suggest that quercetin is the most dentinogenic agent among the tested chemicals. The increase in ALP activity in the quercetin-treated cells was not affected by ICI 182,780, an estrogen receptor inhibitor, and was partially blocked by PD98059, an extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor. This suggests that ERK1/2 is activated in the quercetin-induced differentiation of HDP cells without the mediation of estrogen receptors, which are known to be involved in osteoblast differentiation induced by quercetin.

Correlations between color differences based on three color-difference formulas using dental shade guide tabs.

PURPOSE: The purpose of this study was to determine the correlation among color-difference values based on three formulas between shade tab pairs from two shade guides [Vita Lumin (VITA) and Chromascop (CHRO)]. MATERIALS AND METHODS: The color of shade tabs was measured relative to the standard illuminant D(65) under the 8 degrees standard observer function, and distributions for CIE L*, a*, and b* values were compared. One hundred and twenty shade pairs from VITA and 190 shade pairs from CHRO were used to calculate color differences using CIELAB, DIN99, and CIEDE2000 formulas (DeltaE*(ab), DeltaE(99), and DeltaE(00), respectively). A paired t-test was used to determine the difference between each pair of the three color-difference values (alpha= 0.01). Regression analysis was used to determine the correlations between the color differences (alpha= 0.01). RESULTS: For both shade guides, there were significant differences between DeltaE*(ab) and DeltaE(00), DeltaE*(ab) and DeltaE(99), and DeltaE(99) and DeltaE(00) (p < 0.01). DeltaE*(ab) and DeltaE(00), and DeltaE*(ab) and DeltaE(99) were strongly correlated (r(2)= 0.90 to 0.94, p < 0.05). Although a simplified a* rescaling function of the CIE a* axis has been added in the CIEDE2000 formula, the influence of the opposite signs in the a* value were found to be irrelevant to the DeltaE(00) value. CONCLUSION: DeltaE*(ab),DeltaE(99), and DeltaE(00) can be used interchangeably for the evaluation of color difference of shade tabs.