[Establishment and validation of a nomogram-based predictive model for idiopathic aldosteronism].

Objective: To establish and validate a nomogram-based predictive model for idiopathic hyperaldosteronism (IHA). Methods: This cross-sectional study was conducted with the collected clinical and biochemical data of patients with primary aldosteronism (PA) including 249 patients with unilateral primary aldosteronism (UPA) and 107 patients with IHA, who were treated at the Department of Endocrinology of the First Affiliated Hospital of Chongqing Medical University from November 2013 to November 2022. Plasma aldosterone concentration (PAC) and plasma renin concentration (PRC) were measured by chemiluminescence. Stepwise regression analysis was applied to select the key predictors of IHA, and a nomogram-based scoring model was developed. The model was validated in another external independent cohort of patients with PA including 62 patients with UPA and 43 patients with IHA, who were diagnosed at the Department of Endocrinology, First Affiliated Hospital of Zhengzhou University. An independent-sample t test, Mann-Whitney U test, and χ2 test were used for statistical analysis. Results: In the training cohort, in comparison with the UPA group, the IHA group showed a higher serum potassium level [M(Q1, Q3), 3.4 (3.1, 3.8) mmol/L vs. 2.7 (2.1, 3.1) mmol/L] and higher PRC [4.0 (2.1, 8.2) mU/L vs. 1.5 (0.6, 3.4) mU/L] and a lower PAC post-saline infusion test (SIT) [305 (222, 416) pmol/L vs. 720 (443, 1 136) pmol/L] and a lower rate of unilateral adrenal nodules [33.6% (36/107) vs. 81.1% (202/249)]; the intergroup differences in these measurements were statistically significant (all P<0.001). Serum potassium level, PRC, PAC post-SIT, and the rate of unilateral adrenal nodules showed similar performance in the IHA group in the validation cohort. After stepwise regression analysis for all significant variables in the training cohort, a scoring model based on a nomogram was constructed, and the predictive parameters included the rate of unilateral adrenal nodules, serum potassium concentration, PAC post-SIT, and PRC in the standing position. When the total score was ≥14, the model showed a sensitivity of 0.65 and specificity of 0.90 in the training cohort and a sensitivity of 0.56 and specificity of 1.00 in the validation cohort. Conclusion: The nomogram was used to successfully develop a model for prediction of IHA that could facilitate selection of patients with IHA who required medication directly.

Lactobacillus plantarum ZLP001: In vitro Assessment of Antioxidant Capacity and Effect on Growth Performance and Antioxidant Status in Weaning Piglets.

The objective of this study was to evaluate the antioxidant capacity of Lactobacillus plantarum ZLP001 and its effects on growth performance and antioxidant status in weaning piglets. The survival in hydrogen peroxide and free radical-scavenging activity of Lactobacillus plantarum ZLP001 were analysed in vitro. The Lactobacillus plantarum ZLP001 showed high viability in 1.0 mmol/L hydrogen peroxide and high scavenging ability against hydroxyl, superoxide anion, and DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals which was dose dependent. Ninety-six weaning piglets were selected (7.45±0.79 kg) and divided into three groups comprising of negative control without any supplementation, treatment group with supplemented 6.8×10(7) Lactobacillus plantarum ZLP001 CFU/g of diet, and positive control with antibiotic treatment (chlorotetracycline, 80 mg/kg diet). The results showed that Lactobacillus plantarum ZLP001 supplementation enhanced feed conversion rates in piglets compared with control (p<0.05). Supplementation of Lactobacillus plantarum ZLP001 increased the concentration of superoxide dismutase (p<0.05), glutathione peroxidase (p<0.01) and catalase in serum (p<0.10), while decreased the concentration of malondialdehyde (p<0.05). The present study implies that the strain Lactobacillus plantarum ZLP001 had high antioxidant ability and its supplementation improved the growth performance and antioxidant status of weaning piglets, so it can be considered useful to alleviate oxidative stress and increase productive performance of pigs. (Key Words: Probiotic, Antioxidant Capacity, Weaning Piglet).

High proton conductivity of water channels in a highly ordered nanowire.

A proton-conductive material based on a crystalline assembly of trimesic acid and melamine (TMA⋅M, see picture) is reported. Because of the ordered structure of the assembly, the water-saturated proton conductivity for the TMA⋅M assembly is 5.5 S cm(-1) , which is the highest proton conductivity measured to date. This exceptionally high conductivity and low-cost fabrication of the material make applications feasible for fuel-cell devices.

Online measurement of conductivity/permittivity of fluid by a new contactless impedance sensor.

By expanding the contactless conductivity detection (CCD) technique to contactless impedance detection technique, a new contactless impedance sensor is designed to implement the online measurement for both the conductivity of a conductive fluid and the permittivity of a non-conductive fluid. In the new contactless impedance sensor, a new simulated inductor is developed to overcome the unfavorable influences of the coupling capacitances by impedance elimination principle, and the digital phase-sensitive demodulation (DPSD) technique is adopted to realize the impedance measurement. To verify the effectiveness of the new contactless impedance sensor, simulation experiments (using different resistors, capacitors, and their combinations) and practical fluid experiments (using KCl solutions with different concentrations, eight organic solvents, and pure water) are carried out. The experimental results show that the development of the new contactless impedance sensor is successful and the conductivity/permittivity measurement performance of the new sensor is satisfactory. The maximum relative error of conductivity measurement is 3.1% and the maximum relative error of permittivity measurement is 5.5%. Compared with the conventional conductivity/permittivity sensors, the new sensor can implement the contactless online measurement of both the two electrical parameters of fluid. Meanwhile, the new contactless impedance sensor is suitable for industrial applications and has the advantages of simple construction and low cost.

New fluorescent probes for the detection of mixed sodium and potassium metal ions.

A new fluorescent probe 2 is developed that is capable of measuring the concentration of a mixture of sodium and potassium ions in the solution. This probe contains a fluorophore that is utilized in two ways depending on the pH of the solution.

Micromechanical measurement of active sites on silicon nitride using surface free energy variation.

We have investigated chemical reactions between adsorbed water and active sites on a silicon nitride surface as a function of temperature and relative humidity using microcantilevers. Effects that might produce a change in the response of the microcantilever, such as a mass adsorption, surface tension of the adsorbed water, and changes in thermal conductivity, were systematically investigated. It is shown that the judicious choice of experimental conditions could make these effects essentially inconsequential in comparison with the instrument response produced by the change in free surface energy of the microcantilever due to the chemical reactions. Using this method, the variation in free surface energy when changing from dry to high humidity conditions was found and the number of active sites that reacted was estimated. This method may be extended to other problems for use in determining surface free energy change and thus the density of reactant sites under different conditions of interest.

A double-site absorption model fits to pharmacokinetic data of repaglinide in man.

The plasma concentrations of repaglinide in 16 male subjects were determined after an oral dose of 4 mg. Two-peak concentrations in plasma were observed. A type of one-compartment model with double sites of drug absorption was developed and successfully used to fit the data. A good agreement between observed and predicted data was found in all subjects with correlation index r2 > 0.97. The corresponding pharmacokinetic parameters were estimated as follows: Tmax1 0.61 +/- 0.14 h, Tmax2 1.45 +/- 0.43 h, Cmax1 40.60 +/- 20.57 ng/ml, Cmax2 42.70 +/- 17.54 ng/ml, T1 0.12 +/- 0.07 h, T2 0.67 +/- 0.30 h and T3 1.03 +/- 0.35 h.

Ultrasensitive detection of CrO4(2-) using a microcantilever sensor.

Microcantilevers modified with a self-assembled monolayer respond sensitively to specific ion concentrations. Here, we report the detection of trace amounts of CrO4(2-) using microcantilevers modified with a self-assembled monolayer of triethyl-12-mercaptododecylammonium bromide. The self-assembled monolayer was prepared on a silicon microcantilever coated with a thin layer of gold on one side. The microcantilever undergoes bending due to sorption of CrO4(2-) ions on the monolayer-modified side. It was found that a concentration of 10(-9) M CrO4(2-) can be detected using this technology in a flow cell. Other anions, such as Cl-, Br-, CO3(2-) (or HCO3-), and SO4(2-), have minimal effect on the deflection of this cantilever. The mechanics of the bending and the chemistry of cantilever modification are discussed.

Cantilever-based optical deflection assay for discrimination of DNA single-nucleotide mismatches.

Characterization of single-nucleotide polymorphisms is a major focus of current genomics research. We demonstrate the discrimination of DNA mismatches using an elegantly simple microcantilever-based optical deflection assay, without the need for external labeling. Gold-coated silicon AFM cantilevers were functionalized with thiolated 20- or 25-mer probe DNA oligonucleotides and exposed to target oligonucleotides of varying sequence in static and flow conditions. Hybridization of 10-mer complementary target oligonucleotides resulted in net positive deflection, while hybridization with targets containing one or two internal mismatches resulted in net negative deflection. Mismatched targets produced a stable and measurable signal when only a four-base pair stretch was complementary to the probe sequence. This technique is readily adaptable to a high-throughput array format and provides a distinct positive/negative signal for easy interpretation of oligonucleotide hybridization.