Biomimetic synthesis of struvite with biogenic morphology and implication for pathological biomineralization

published_or_final_versio

Maximum age limitation in luminescence dating of Chinese loess using the multiple-aliquot MET-pIRIR signals from K-feldspar

Numerical dating of loess is important for Quaternary studies. Recent progress in post-infrared infrared-stimulated luminescence (pIRIR) signals from potassium-rich feldspar has allowed successful dating of Chinese loess beyond the conventional dating limit based on quartz optically stimulated luminescence (OSL) signals. In this study we tested the multiple-aliquot regenerative-dose (MAR) pre-dose multiple-elevated-temperature post-IR IRSL (pMET-pIRIR) procedure on samples from the palaeosol S5 (∼480 ka) and S8 (∼780 ka) layers from the Luochuan and Jingbian sections, respectively. The results show that (1) compared to sensitivity-corrected signal (Lx/Tx), a higher saturation dose is observed for the sensitivity-uncorrected MET-pIRIR signals (Lx), suggesting that MAR is advantageous for dating old samples; (2) negligible fading component can be achieved using the pMET-pIRIR procedure; (3) for the sample from the top of palaeosol S5, De values (1360 + 226/-167 Gy) broadly consistent with expected De (1550 ± 72 Gy) can be obtained using the sensitivity-uncorrected 300 °C MET-pIRIR signal. Our study suggests that a De value of about 1800 Gy may be the maximum dating limit of Chinese loess using the MAR pMET-pIRIR procedure.postprin

Diagnosis Code Assignment Using Sparsity-Based Disease Correlation Embedding

© 1989-2012 IEEE. With the latest developments in database technologies, it becomes easier to store the medical records of hospital patients from their first day of admission than was previously possible. In Intensive Care Units (ICU), modern medical information systems can record patient events in relational databases every second. Knowledge mining from these huge volumes of medical data is beneficial to both caregivers and patients. Given a set of electronic patient records, a system that effectively assigns the disease labels can facilitate medical database management and also benefit other researchers, e.g., pathologists. In this paper, we have proposed a framework to achieve that goal. Medical chart and note data of a patient are used to extract distinctive features. To encode patient features, we apply a Bag-of-Words encoding method for both chart and note data. We also propose a model that takes into account both global information and local correlations between diseases. Correlated diseases are characterized by a graph structure that is embedded in our sparsity-based framework. Our algorithm captures the disease relevance when labeling disease codes rather than making individual decision with respect to a specific disease. At the same time, the global optimal values are guaranteed by our proposed convex objective function. Extensive experiments have been conducted on a real-world large-scale ICU database. The evaluation results demonstrate that our method improves multi-label classification results by successfully incorporating disease correlations

Application of a novel fluorescence probe in the determination of nucleic acids

A novel fluorimetric method has been developed for rapid determination of DNA and RNA with hypocrellin A (HA) as a fluorescence probe, based on the fluorescence enhancement of HA in the presence of DNA or RNA. Maximum fluorescence is produced in the pH range 3.4-4.0, with maximum excitation and emission wavelengths at 470 and 600 nm, respectively. Under optimal conditions, the calibration graphs are linear over the range 0-200.0 ng cm(-3) for calf thymus DNA and 13.0-200.0 ng cm(-3) for yeast RNA, respectively. The corresponding detection limits are 5.0 ng cm(-3) for calf thymus DNA and 13.0 ng cm(-3) for yeast RNA. The relative standard deviation of six replicate measurements is 4.5% for 100 ng cm(-3) calf thymus DNA, DNA could be determined in the presence of 20% m/m yeast RNA. The mechanism for the binding of HA to DNA is also studied

Temperature modulated solubility and activity alteration for oligo-(N-isopropylacrylamide)-iron tetrasulfonatophthalocyanine conjugates as a new mimetic peroxidase

Iron tetrasulfonatophthalocyanine (FeTSPc) was covalently bound to the terminus of a temperature sensitive oligomer, oligo-N-isopropylacrylamide (ONIPAAm), to form a new mimetic enzyme (ONIPAAm-FeTSPc) to; mimic the peroxidase activity of horseradish peroxidase. This FeTSPc-based mimetic enzyme exhibits a lower critical solution temperature (LCST) of 32 degrees C in neutral solution. It precipitates from water above the LCST and redissolves when the solution temperature is lowered below the LCST. The peroxidase activity of this mimetic enzyme was studied based on its catalytic effect on the reaction of p-hydroxyphenylpropionic acid and H2O2 The results show that the peroxidase activity of the new mimetic enzyme is higher than that of the free FeTSPc. The possibility of its application in the analytical field was also tested by the determination of H2O2 and ONIPAAm-FeTSPc; the detection limits are 8.2 x 10(-9) and 1.7 x 10(-9) mol L-1, respectively

Clinical significance and therapeutic value of glutathione peroxidase 3 (GPx3) in hepatocellular carcinoma

AIMS: We aimed to investigate the clinical significance of GPx3 in hepatocellular carcinoma (HCC) and to characterize its tumor suppressive role. METHODS: HCC patients (113) who underwent hepatectomy were recruited to examine the clinical relevance of GPx3. The tumor suppressive role of GPx3 was studied by administration of recombinant GPx3 (rGPx3) or over-expression of GPx3 in HCC cells in vitro and in vivo. The therapeutic value of GPx3 for HCC was further investigated using human induced pluripotent stem cell derived mesenchymal stem cells (hiPSC-MSCs) as its delivery vehicle. RESULTS: Down-regulation of GPx3 significantly correlated with advanced tumor stage (P = 0.024), venous infiltration (P = 0.043) and poor overall survival (P = 0.007) after hepatectomy. Lower plasma GPx3 in HCC patients was significantly associated with larger tumor size (P = 0.011), more tumor nodules (P = 0.032) and higher recurrence (P = 0.016). Over-expression of GPx3 or administration of rGPx3 significantly inhibited proliferation and invasiveness of HCC cells in vitro and in vivo. Tumor suppressive activity of GPx3 was mediated through Erk-NFκB-SIP1 pathway. GPx3 could be delivered by hiPSC-MSCs into the tumor and exhibited tumor suppressive activity in vivo. CONCLUSIONS: GPx3 is a tumor suppressor gene in HCC and may possess prognostic and therapeutic value for HCC patients.published_or_final_versio

Two populations of X-ray pulsars produced by two types of supernovae

Two types of supernova are thought to produce the overwhelming majority of neutron stars in the Universe. The first type, iron-core collapse supernovae, occurs when a high-mass star develops a degenerate iron core that exceeds the Chandrasekhar limit. The second type, electron-capture supernovae, is associated with the collapse of a lower-mass oxygen-neon-magnesium core as it loses pressure support owing to the sudden capture of electrons by neon and/or magnesium nuclei. It has hitherto been impossible to identify the two distinct families of neutron stars produced in these formation channels. Here we report that a large, well-known class of neutron-star-hosting X-ray pulsars is actually composed of two distinct sub-populations with different characteristic spin periods, orbital periods and orbital eccentricities. This class, the Be/X-ray binaries, contains neutron stars that accrete material from a more massive companion star. The two sub-populations are most probably associated with the two distinct types of neutron-star-forming supernovae, with electron-capture supernovae preferentially producing system with short spin period, short orbital periods and low eccentricity. Intriguingly, the split between the two sub-populations is clearest in the distribution of the logarithm of spin period, a result that had not been predicted and which still remains to be explaine

Study on fluorometric determination of hydrogen peroxide catalyzed by iron(III)-tetrasulfonato-phthalocyanine with thiamine hydrochloride as a substrate

Iron(III)-tetrasulfonatophthalocyanine(FeTSPc) has been used as a mimetic enzyme in the determination of hydrogen peroxide with thiamine hydrochloride as a fluorogenic substrate. The determinations were carried out in both acidic and basic environments, with different limits of detection and linear ranges. In acidic condition, the linear calibration graph was obtained from 5.0x10(-8) mol/L to 8.0x10(-6) mol/L, with a detection limit of 2.1x10(-8) mol/L H2O2 when Na2HPO4-citric buffer solution (pH 2.8) was used as the reaction medium. It was also found that using one of the three polybasic carboxylic acids such as citric acid, tartaric acid and malonic acid as the catalytic reaction medium can lead to particularly sensitive systems, permitting a detection limit as low as 3.5x10(-9) mol/L H2O2; whereas in basic reaction medium (Na2CO3-NaHCO3 buffer solution, pH = 10.0), the linear range of the calibration graph was from 5.0x10(-8) mol/L to 2.0x10(6) mol/L H2O2 with a detection limit of 1.4x10(-8) mol/L. The applicability of the method to the determination of glucose in human serum was demonstrated by investigating the recovery of the known glucose added to human serum

A new red-region substrate, tetra-substituted amino aluminium phthalocyanine, for the fluorimetric determination of H2O2 catalyzed by mimetic peroxidases

A new red-region fluorogenic substrate, tetra-substituted amino aluminium phthalocyanine, was developed for the selective determination of H2O2 based on the catalytic effect of mimetic peroxidases, viz., hemin or iron tetrasulfonatophthalocyanine (FeTSPc). Under the optimum conditions, the linearity of the calibration graph for the determination of H2O2 with hemin (or FeTSPc) as the catalyst was in the range from 0.0 to 3.0 X 10(-7) mol L-1 (or from 0.0 to 2.0 x 10(-6) mol L-1). The detection limits were 3.7 X 10(-9) and 4.9 x 10(-9) mol L-1 H2O2, respectively. The relative standard deviation (n = 7) was within 1.5% in the middle of the linear range. The peroxidase activity of the mimetic enzymes hemin and FeTSPc, the effects of some experimental conditions and the influence of foreign substances were investigated. With this substrate, 0.0-7.5 x 10(-8) mol L-1 hemin and 0.0-2.0 x 10(-6) mol L-1 FeTSPc can be determined with an accuracy and precision of about 1.3%. The potential application of the reagent was tested by the determination of H2O2 in rainwater

Sensitive fluorimetric determination of formaldehyde by the co-quenching effect of formaldehyde and sulfite on the fluorescence of tetra-substituted amino aluminium phthalocyanine

A novel and sensitive fluorimetric method was developed for the determination of formaldehyde based on the co-quenching effect of formaldehyde and sulfite on the fluorescence of tetra-substituted amino aluminium phthalocyanine. Formaldehyde in the concentration range 0.040-1.19 mug ml(-1) can be determined with a limit of detection of 7.5 ng ml(-1). The relative standard deviation for nine replicate measurements of 80.0 ng ml(-1) formaldehyde is 1.8%. The method was applied to the analysis of real samples with satisfactory results