Self-Reference Analysis Based on Temperature Difference Absorption Spectra.

The direct qualitative identification of pure liquids in laboratories and in security checks is generally performed by the detection of the refractive index or the permittivity. However, refractive indices are strongly influenced by temperature, while the permittivities of some organics are difficult to differentiate. On the other hand, the quantitative monitoring of samples with high concentration in plating baths and in chemical production lines are generally performed via a "Sampling-Dilution-Analysis" approach because of significant deviations from the linear range at high concentration, which makes the real-time monitoring of concentrated samples difficult. Here, we propose a self-reference analysis (SRA) method to directly analyze pure liquids and concentrated samples based on temperature difference absorption spectra (TDAS) without the need for dilution. This method was performed by simultaneously scanning the spectra of the reference and the sample, which are both obtained from the same analyte for detection but are at different temperatures. Compared to conventional absorption spectra with a blank reference, the red-shifted peak wavelengths of TDAS enable the detection of many far UV absorptive compounds in the near-ultraviolet region (λ > 190 nm). More importantly, organic compounds with similar structures can be easily distinguished. In addition, TDAS can also be used for the quantitative detection of concentrated analytes. The proposed SRA-TDAS method is a rapid and effective method; this approach does not require dilution and utilizes a self-reference, implying the wide potential applicability in security checks, and the real-time monitoring of concentrated compounds in chemical production lines.

Diagnostic accuracy of a selected signature gene set that discriminates active pulmonary tuberculosis and other pulmonary diseases.

OBJECTIVE: We validated the accuracy of host selected signature gene set using unstimulated whole blood (WB), and peripheral blood mononuclear cells (PBMC) in the diagnosis of tuberculosis (TB). METHODS: The unstimulated WB and PBMC from 1417 individuals with active pulmonary TB patients, other lung diseases and healthy participants were analyzed using real time polymerase chain reaction (RT-PCR). RESULTS: The WB cohort test demonstrates that the combination of GBP5 and KLF2 can differentiate active TB versus HC with sensitivity and specificity of 77.8% and 87.1%, respectively; but most importantly active TB versus OD with sensitivity and specificity of 96.1% and 85.2%, respectively. Again during treatment course, the TB score of GBP5 and KLF2, analytes secretion and clinical parameters were found to be associated in disease progression. In the PBMC cohort test, we found that the only and best discriminatory combination was GBP5, DUSP3 and KLF2 inthe active TB versus HC with a sensitivity and specificity of 76.4% and 85.9%, respectively. CONCLUSIONS: Our study reveals that GBP5 and KLF2 may be useful as a diagnostic tool for active TB, also the two-gene set may serve as surrogate biomarkers for monitoring TB therapy.

[Monitoring report of Oncomelania hupensis snails in Huizhou District in 2013].

OBJECTIVE: To further master the Oncomelania hupensis snail situation in Huizhou District, so as to provide the evidence for improving the prevention and control work. METHODS: According to the prevalence of schistosomiasis in history and the characteristics of residual snail points in recent years, the snail surveys were carried out with the environmental sampling and systematic sampling method in history snail environments and their surrounding suspicious environments. RESULTS: Totally 5,298,940 m2 in 12 administrative villages of 3 townships were investigated and there were 24 406 m2 snail areas at 5 remaining snail spots in 4 administrative villages. The highest snail density was 283 snails/0.1 m2, and the average density of living snails was 2.31 snails/0.1 m2. A total of 4,303 snails were captured, 1,534 were checked by microscopy, and no infected snails were found. CONCLUSION: The snail situation is still not stable in Huizhou District, and the monitoring of snail situation still need to be strengthened.

[Variation characteristics and mathematical model of humic substances in landfill leachates with different landfill ages].

The influence of municipal landfill age on the characteristics of humic substances in leachate on the basis of investigating 12 different kinds of leachates from landfills in Fujian province is presented in this study. It was shown that the concentration and percentage of fulvic acid (FA) were obviously higher than those of humic acid (HA). As the landfill age increased, the concentrations of HA, FA and humic substances (HS) increased, moreover, the percentage of HA first increased and then decreased. While the percentages of FA and HS first increased and then fluctuated with the landfill age. The UV-Vis analytical results of HA and FA through E280, E300/E400 and E465/E665 revealed that HA had a relatively higher content of aromatic compounds and higher molecular weight than FA. The humification of FA had a tendency to increase as the landfill age increased, while HA had opposite result. The E300/E400 and E465/E665 of HA and FA fluctuated with increasing landfill age. A mathematical model simulating the concentration of humic substances varied with the landfill age was presented and demonstrated based on degradation kinetics. The simulated results were close to the measured values with a correlation coefficient R2 of 0.820, 0.932 and 0.946, respectively, indicating that the concentrations of HA, FA and HS could be accurately forecasted.

Study on the electrochemical catalytic properties of the topological insulator Bi2Se3.

In this work, the electrochemical catalytic properties of the topological insulator bismuth selenide (Bi2Se3) were first studied. In the presence of Bi2Se3 the reduction current of dissolved O2 could be significantly enhanced. The electron transfer resistivity (Rct) was greatly reduced at the Bi2Se3-PVP modified electrode as evidenced by the electrochemical impedance spectrometry, implying that the topological insulator Bi2Se3 could facilitate the electron transfer at the interface due to the excellent surface conductivity. Based on the high electrochemical catalytic activity for the reduction of dissolved O2, the Bi2Se3-PVP modified electrode was used to detect glucose with the modification of glucose oxidase, and applied for the detection of glucose in human blood serum.

[Investigation on status of Oncomelania hupensis in schistosomiasis transmission-interrupted areas of Huangshan City].

OBJECTIVE: To explore a new monitoring method for schistosomiasis transmission interrupted areas, so as to evaluate the monitoring results in counties (districts) to improve the quality. METHODS: Specialized technicians were selected as survey teams to investigate the status of Oncomelania hupensis snails with the random sampling method combined with environmental sampling method every year from 1997 to 2013. RESULTS: From 1997 to 2013, 118 villages of 38 townships of 21 counties were investigated for the snail status, and there were 18 environments with snails in 10 townships of 7 counties. The snail area was 10.91 hm2. CONCLUSION: There are still small snail areas. Therefore, the snail monitoring should still be strengthened by specialized technicians.

[Investigation on newly advanced schistosomiasis patients in schistosomiasis transmission-interrupted areas].

There were 240 newly advanced schistosomiasis patients in Huangshan City from 2004 to 2011. All the patients were clinically diagnosed and mainly distributed in the countries which were once heavy endemic areas in history. Most of the patients were diagnosed in 2007 and 2008, and those aged more than 60 years accounted for 79.16% of the total cases. Among all the cases, ascites type and splenomegaly type accounted for 66.25% and 31.66% respectively. In conclusion, there are still newly advanced schistosomiasis cases in areas of schistosomiasis transmission interruption, so the monitoring, diagnosis and treatment of historical schistosomiasis patients should be strengthened.

Rapid visual detection of aluminium ion using citrate capped gold nanoparticles.

We report the visual detection of Al(3+) using unlabeled gold nanoparticles (AuNPs) based on the complexation of Al(3+) with citric acid, resulting in the aggregation of AuNPs. The distinction of color change can be observed by the naked eye at concentrations down to 1.0 µM which is lower than the permissable level (7.4 µM) for drinking water as defined by the World Health Organization.

Monitoring of peptide-specific and gamma interferon-productive T cells in patients with active and convalescent tuberculosis using an enzyme-linked immunosorbent spot assay.

To establish a high-efficiency gamma interferon-specific enzyme-linked immunosorbent spot assay (IFN-γ ELISPOT assay) for detection of tuberculosis (TB), peptides (E6, E7, and C14) and peptide mixtures (E6 plus E7 and E6 plus E7 plus C14) were used to monitor peripheral blood (PBL) samples from patients with pulmonary TB (PTB), as well as control samples. The positive detection rates of the five IFN-γ ELISPOT assays were 78.38%, 74.86%, 55.83%, 90.43%, and 91.51%, respectively, and there were similar detection rates between the two combined peptide mixture IFN-γ ELISPOT assays and the tuberculin skin test (TST) (90.62% versus 95.59%). No significant difference was found between the detection rates of the two combined peptide mixture IFN-γ ELISPOT assays and the T-SPOT.TB assay for 86 patients with PTB (P > 0.05), but the median number of spot-forming cells/10(6) cells (SFP value) for positive results was higher by the former than by the latter assay (P < 0.05). In contrast, the 29.93% positive detection rate and median SFP value of 482 by the two combined peptide mixture IFN-γ ELISPOT assays were significantly higher than the corresponding values of 14.29% and 152 by T-SPOT.TB assay for the same 147 community donors (P < 0.05). For nine PTB patients tracked, the SFP value of 7 for the two peptide mixture IFN-γ ELISPOT assays began to decrease from the second month after regular treatment. A relatively low, almost normal, SFP level was reached and maintained after the third or fourth month. Two in-house IFN-γ ELISPOT assays and the T-SPOT.TB assay could reduce the false-positive and false-negative detection rates of TST and sputum acid-fast staining. Therefore, these two combined peptide mixture IFN-γ ELISPOT assays have a potential advantage, beyond their greater specificity and sensitivity, for use in screening and detection of active TB infection (TBI) and latent TB infection (LTBI) in China.

Electrogenerated chemiluminescence of bis[4-(dimethylamino)phenyl]squaraine.

For the first time, we reported the strong electrogenerated chemiluminescence of organic dye, bis[4-(dimethylamino)phenyl]squaraine (BDPSQ), a high quantum yield and light-stable species, which might find applications in ECL analysis and imaging.

Electrogenerated chemiluminescence from Au nanoclusters.

Electrogenerated chemiluminescence (ECL) of Au clusters is observed for the first time using triethyamine (TEA) as the coreactant. The potential application of ECL Au clusters in analytical chemistry is also demonstrated using Pb(2+) as an example.

[Surveillance of schistosomiasis after its transmission being interrupted in Huangshan City, 1994-2010].

In Huangshan City, schistosomiasis surveillance from 1994 to 2010 showed that there were no patients and livestock newly infected with schistosome, no infected Oncomelania snails, but the snail status was stable. It is suggested that the schistosomiasis control strategy with emphasis on snail surveillance is effective, and snail surveillance is still a key measure of schistosomiasis surveillance in the future.

Hot electron induced cathodic electrochemiluminescence at AuSb alloy electrode for fabricating immunosensor with self-assembled monolayers.

Thin antimony oxide covered AuSb alloy electrode was firstly found to be an excellent cold cathode for generating hot electrons during cathodic pulse polarization. Owing to the injection of hot electrons and the subsequent generation of hydrated electrons, fluorescein iso-thiocyanate (FITC) that cannot be excited in common ECL was cathodically excited at the alloy electrode. Self-assembled thiol monolayers were formed on the electrode surface due to the presence of Au in the alloy, to which strepavidin was covalently bound, and then biotinylated antibody was immobilized through the strepavidin-biotin interaction. As a simple model, an immunosensor for the detection of human IgG (hIgG) using FITC as labeling agent was fabricated. ECL signals were responsive to the amount of hIgG bounded to the immunosensor. The ECL intensity was linearly changed with the logarithm of hIgG concentration in the range of 1.0-1000 ng mL(-1), and the detection limit was ca. 0.3 ng mL(-1) (S/N=3). The proposed immunosensor showed a broad linear range (three magnitudes), good reproducibility and stability, which is promising in detecting FITC-based labels in various types of bioaffinity assays.

An extremely stable and sensitive end-column electrochemical detector based on heated copper microdisk electrode with direct current for CE and CE-Chip.

A heated copper microdisk electrode (HCME) was fabricated and successfully applied to capillary electrophoresis (CE) and CE-Chip as an electrochemical detector (ECD) for the detection of three carbohydrates and shikimic acid (SA) in Illicium verum Hook F., respectively. The temperature of HCME was heated by twin-wire-wound coil with direct current to reduce the magnetic interference. Coupled with CE and CE-chip, this detector exhibits both extremely stable and sensitive performance at elevated temperature compared with that at room temperature. In successive detection of three carbohydrates and shikimic acid (SA), the HCME exhibits very stable response with RSD of ca. 2% with elevated temperature without renewing the electrode, while at room temperature, RSD of ca. 20% is obtained. This is very important in practical applications that tedious works, such as polishing and re-fixing the electrode at each detection, can be therefore avoided. In addition, the sensitivity is about 2-6 time increased, and the linear range is about an order wider at elevated temperature (ca. 60 degrees C) than that at room temperature (ca. 25 degrees C).

Catalytic electrogenerated chemiluminescence and nitrate reduction at CdS nanotubes modified glassy carbon electrode.

Electrochemical and electrogenerated chemiluminescence (ECL) properties of a glassy carbon electrode modified with CdS nanotubes (CdS-GCE) are investigated in neutral media. The cyclic voltammogram (CV) shows two cathodic peaks (P(C1) and P(C2)) at -0.76 and -0.97 V and an anodic peak (P(A)) at -0.8 V, while two ECL peaks around -0.76 V are observed. Similar mechanisms of both ECLs are supposed and possibly related to the capture of an electron at a surface trap, that is, the surface sulfide vacancy (V(S)(2+)) of CdS nanotubes and its electrocatalytic reduction to H(2)O(2) generated from the dissolved oxygen. P(C2) and P(A) are ascribed to the two-electron redox at V(S)(2+). Moreover, electrocatalysis to nitrate reduction is also found at P(C2), with a good linear relationship between nitrate concentration and electrocatalytic peak current in CV.