A Transportable Atomic Gravimeter with Constraint-Structured Active Vibration Isolation.

Many efforts have been taken in recent years to push atomic gravimeters toward practical applications. We demonstrate an atomic gravimeter named NIM-AGRb2 that is transportable and suitable for high-precision gravity measurements. Constraint-structured active vibration isolation (CS-AVI) is used to reduce the ground vibration noise. The constraint structure in CS-AVI ensures that the isolation platform only has vertical translation, with all other degrees of freedom (DoFs) being constrained. Therefore, the stability of active vibration isolation is enhanced. With the implementation of CS-AVI, the sensitivity of NIM-AGRb2 reached as low as 20.5 µGal/Hz1/2. The short-term sensitivity could be further reduced to 10.8 µGal/Hz1/2 in a seismologic observation station. Moreover, we evaluated the system noise of the gravimeter, and the results were consistent with our observations.

Oral vitamin D supplementation has a lower bioavailability and reduces hypersecretion of parathyroid hormone and insulin resistance in obese Chinese males.

OBJECTIVE: To examine the vitamin D status, SNP of the vitamin D receptor gene (VDR) and the effects of vitamin D supplementation on parathyroid hormone and insulin secretion in adult males with obesity or normal weight in a subtropical Chinese city. DESIGN: An intervention trial. SETTING: Shenzhen City, Guangdong Province, China. SUBJECTS: From a cross-sectional survey conducted from June to July, eighty-two normal-weight and ninety-nine obese males (18-69 years) were screened to analyse their vitamin D status and for five SNP of VDR. From these individuals, in the same season of a different year, obese and normal-weight male volunteers (twenty-one per group) were included for an intervention trial with oral vitamin D supplementation at 1250 µg/week for 8 weeks. RESULTS: For the survey, there was no significant difference (P>0·05) in baseline circulating 25-hydroxyvitamin D concentrations or in the percentages of participants in different categories of vitamin D status between the two groups. The VDR SNP, rs3782905, was significantly associated with obesity (P=0·043), but none of the examined SNP were correlated with serum 25-hydroxyvitamin D when adjusted for age, BMI and study group. After vitamin D supplementation, serum 25-hydroxyvitamin D concentration, hypersecretions of parathyroid hormone and insulin, and insulin resistance in the obese were changed beneficially (P<0·05); however, the increase in serum 25-hydroxyvitamin D was less than that of the normal-weight men. CONCLUSIONS: For obese and normal-weight men of subtropical China, the summer baseline vitamin D status was similar. However, oral vitamin D supplementation revealed a decreased bioavailability of vitamin D in obese men and ameliorated their hypersecretion of parathyroid hormone and insulin resistance.

A prediction model for nonresponsive outcomes in critically ill patients with acute respiratory distress syndrome undergoing prone position ventilation: A retrospective cohort study.

OBJECTIVE: This study aimed to develop a reliable and effective nomogram model to identify high-risk populations with non-response to prone position ventilation (PPV) in acute respiratory distress syndrome (ARDS) patients. METHODS: This retrospective cohort study included 175 patients with ARDS undergoing PPV. An improvement of ≥ 20 mmHg in the PaO2/FiO2 after the first PPV was defined as a 'response'. For the construction of the model, all patients were randomly assigned to the train and validation cohort according to 2:1. Multivariate logistic regression was useed to develop the nomogram. The area under the receiver operating characteristic curve (AUC), decision curve and calibration curve were assessed to evaluate the efficiency, clinical utility and calibration of the model. RESULTS: The overall rate of non-response to PPV in ARDS patients was approximately 32.6 %. In the training cohort and validation cohort, the rate are 29.9 % and 34.5 % respectively. Murray score ≥ 2.5 (OR: 4.29), procalcitonin (PCT) ≥ 2 ng/mL (OR: 2.52), N-terminal pro-B-type natriuretic peptide (Nt-proBNP) ≥ 2000 pg/ml (OR: 2.44), and hemoglobin ≤ 90 g/L (OR: 2.39) were independently associated with the rate of non-response to PPV and combined in prediction model. The model demonstrated good predictive value with AUC of 0.817 and 0.828 in the train and validation cohort. Calibration curve showed good calibration and decision curve analysis indicated favorable clinical utility. CONCLUSIONS: This study constructed a risk prediction model for non-response to PPV, which demonstrated good predictive value and clinical utility. IMPLICATIONS FOR CLINICAL PRACTICE: Early identification of prone position response in ARDS is essential for timely alternative treatments, improving patient prognosis and healthcare efficiency. The predictive model included representative indicators of patients with ARDS, encompassing parameters such as the acute lung injury (Murray score), cardiac function (Nt-proBNP), infectious status (PCT), and hemoglobin levels.

Adsorption of Pb(II), Cr(III), Cu(II), Cd(II) and Ni(II) onto a vanadium mine tailing from aqueous solution.

The adsorption of heavy metal cations Pb(II), Cr(III), Cu(II), Cd(II) and Ni(II) from aqueous solution by a mine tailing which mainly contains muscovite was investigated. The property of the mineral was investigated by using SEM, FT-IR, XRD and BET analysis. pH(pzc) was measured by an titration technique to give a value of 5.4+/-0.1. Kinetics experiments indicated that the processes can be simulated by pseudo-second-order model. Total adsorption amounts of the heavy metal increased, while the adsorption density decreased when the solid-to-liquid ratio (S/L) increased. Grain size did not affect the adsorption capacity significantly. The resulting isotherms can be described by Frendlich relationship. And the maximum adsorption capacity (molar basis) followed the order of Cr(III)>Pb(II)>Cu(II)>Ni(II)>Cd(II). Thermodynamic analysis showed that the adsorption processed were endothermic and may be chemical in nature with positive DeltaH(0). The positive DeltaS(0) suggested that dissociative processed were involved. Small positive DeltaG(0) suggested that the adsorption processes required a small amount of energy. Adsorption processes were slightly affected by electrolyte ion concentration but strongly dependent on pH value. The most possible mechanism of the adsorption processes involve the inner-sphere-complexions by the aluminol or silanol groups on the surface of the mineral.