New screening tool for neonatal nutritional risk in China: a validation study

Objective A neonatal nutritional risk screening tool (NNRST) was developed by using Delphi and analytic hierarchy processes in China. We verified the accuracy of this tool and analysed whether it effectively screened neonates with nutritional risk.Design Prospective validation study.Setting and participants In total, 338 neonates who were admitted to the neonatal unit of Children’s Hospital of Chongqing Medical University from May–July 2016 completed the study. Nutritional risk screening and length and head circumference measurements were performed weekly. Weight was measured every morning, and other relevant clinical data were recorded during hospitalisation.Main outcome measures We evaluated the sensitivity, specificity, validity, reliability, and positive and negative predictive value of the screening tool. Various characteristics of neonates in different risk groups were analysed to determine the rationality of the nutritional risk classification.Results The sensitivity, specificity, and positive and negative predictive values were 85.11%, 91.07%, 60.61% and 97.43%, respectively. The criterion validity was texted by the Spearman correlation analysis (r=0.530) and independent samples non-parametric tests (p=0.000). The content validity (Spearman correlation coefficient) was 0.321–0.735. The inter-rater reliability (kappa value) was 0.890. Among the neonatal clinical indicators, gestational age, birth weight, length, admission head circumference, admission albumin, admission total proteins, discharge weight, discharge length and head circumference decreased with increasing nutrition risk level; the length of stay and the rate of parenteral nutrition support increased with increasing nutrition risk level. In the comparison of complications during hospitalisation, the incidence of necrotising enterocolitis and congenital gastrointestinal malformation increased with increasing nutrition risk level.Conclusion The validation results for the NNRST are reliable. The tool can be used to preliminarily determine the degree of neonatal nutritional risk, but its predictive value needs to be determined in future large-sample studies.Trial registration number ChiCTR2000033743

Oxidation of low carbon steel in moist atmospheres

In metal coating processes, steel oxidation can take place in direct fired furnaces when unexpected stoppages occur. Leakage ofair into the furnace chamber results in oxidising atmospheres containing H2 or O2 and H2O. When the temperature is higher than570°C, a stable wüstite can form and rapid oxide scale formation results.Experiments were conducted on low carbon steel in wet nitrogen gas atmospheres in the temperature range 800 to 1200°C. Allmeasured oxidation kinetic rate constants were orders of magnitude smaller than theoretical predictions. The slow rates arepartially due to the unbuffered nature of the gas.Well-controlled oxidation experiments were carried out on the low carbon steel in a series of N2-H2-H2O gas atmospheres attemperatures of 800 to 1200°C, where wüstite is the only stable iron oxide product.With fixed pO2 and temperature, according to Wagner's solid-state diffusion theory the parabolic rate constant should be fixed.However, kp values were much smaller than predicted, and kp increased with increasing pH2O. It is proposed that the mobile speciein solid-state diffusion is hydroxyl, and kp is proportional to pH2O0.5.With fixed pH2O and temperature, kp increased with increasing pO2. At 900°C, kp is proportional to pO20.4, but is proportional to pO2 at985°C. Measured kp was much smaller than the predicted results. However, the dependence of kp on pO2 was close to solid-statediffusion based theoretical prediction at both temperatures.Pure iron always reacts much faster than low carbon steel. Oxidation rate constants for iron were in good agreement withtheoretical predictions. The slow steel kinetics could be due to its manganese content, leading to formation of an (FeMn)O solidsolution. The mechanism is not clear.At the same temperature, kp values of low carbon steel oxidation were affected by both pH2O and pO2. The relationship is describedby kp=αpO2"1/n +βpH2O"1/2, where n is a temperature dependent parameter, α and β are related to vacancy and hydroxylpermeability. The different values of α and β for the two materials account for the large differences in oxidation behaviour betweenpure iron and low carbon steel observed in reducing gas atmospheres.When low carbon steel and pure iron were oxidized in O2-H2O gas atmospheres, multi-layer scales developed. Low carbon steeland pure iron had similar kp values, always in reasonable agreement with Wagner's solid-state diffusion predictions

Metal dusting of iron and low alloy steel

Metal dusting is a kind of catastrophic corrosion phenomenon that can be observed in several of petrochemical processes. It occurs on iron-, nickel- and cobalt-base metals in carbonaceous atmospheres at high temperature when gaseous carbon activity is higher than one. The process is particularly rapid for ferritic alloys.The aim of this project was to compare the dusting kinetics of pure iron and a 2.25Cr-1Mo alloy steel under CO-H2-H2O atmosphere at 650°C.Polished (3μm) samples of iron and the steel were exposed to flowing CO-H2-H2O gas atmospheres at 650ºC, when the gases were supersaturated with respect to graphite. The partial pressure of CO was varied between 0.25 and 0.9 atm, and the carbon activity was varied from 2.35 to 16, in order to obtain a series of experimental conditions. In most experiments, pO2 was less than 7.37E-24 atm, and no iron oxide could form. However, Cr2O3 would always have been stable. When exposed to these gases, both iron and steel developed a surface scale of Fe3C which was buried beneath a deposit of carbon, containing iron-rich nanoparticles (the dust). Examination by Scanning Electron Microscopy allowed the observation of fine and coarse carbon nanotubes, and also spiral filaments. However, the morphology of the graphitic carbon was not sensitive to pCO and aC. Moreover, the carbon deposit was gas permeable, allowing continuing gas access to the underlying metal.At a fixed=4.5, the carburizing rate clearly increased with CO content from 0.25 to 0.68 atm. However, increasing the CO content to higher value led to decreased rates, indicating that carburizing rate reaches a maximum value at pCO=0.68 atm. When pCO was fixed at 0.25 atm and 0.68 atm, and carbon activity was varied. The induction period was extended by the formation of protective oxide layers at low values of carbon activity (aC= 2.35 and 2.55) where pO2 exceed the iron oxide formation value. For other reaction conditions, the carbon uptake rate for iron and steel did not increase with aC. The present work showed that the carbon deposition rates were not proportional to pCO or pCOpH2. Instead, the rate was affected by the partial pressure of all three reaction gases, and the carbon uptake rate for both materials could be expressed at r=k1pCOpH2+k2pCO2+k3pH22 and the rate constant k3 has a negative value, corresponding to coke gasification. From XRD analyses, it was found that cementite was the only iron-containing phase in the dusting product. The cementite particles acted as catalysts for carbon deposition from the gas. The same deposition process at the surface of the cementite layer led to its disintegration, thereby producing the particles. This disintegration process was faster on the steel than on pure iron. Consequently, the rates of both metal wastage and coke accumulation were faster for the steel.It is concluded that chromium and molybdenum do not stabilize the carbide but accelerate its disintegration process. It is suggested that Cr2O3 fine particles in the cementite layers provide more nucleation sites in the cementite layer on steel, explaining its more rapid dusting kinetics. However, appropriate methods of proving this assumption, such as TEM and FIB, are required

Exploratory laparoscopy combined with pathological examination in the diagnosis of obscure gastrointestinal bleeding in a child: a case report

Abstract Background The diagnosis of obscure gastrointestinal bleeding (OGIB) which is defined as bleeding of unknown origin of the small bowel by routine evaluation in childhood is a challenge. Case presentation Here we report a one-year-old Chinese girl who was suspected with idiopathic pulmonary haemosiderosis (IPH) and referred to our department for further diagnosis. Finally she was diagnosed with vascular malformations (VM) by exploratory laparoscopy combined with pathological examination. Conclusions Children OGIB could be easily misdiagnosed in the beginning, and OGIB children with active ongoing bleeding may benefit from proceeding directly to exploratory laparoscopy, followed by pathological confirmation of the diagnosis

Precise and accurate Re-Os isotope dating of organic-rich sedimentary rocks by thermal ionization mass spectrometry with an improved H2O2-HNO3 digestion procedure

This contribution presents a new method for Re-Os isotope dating organic-rich sedimentary (ORS) rocks by thermal ionization mass spectrometry using an H2O2-HNO3 solution as the digestion medium, rather than CrO3-H2SO4 or inverse aqua regia. The main underlying principle of this method is that H2O2-HNO3 digestion would preferentially liberate hydrogenous Re and Os, and minimize the dissolution of non hydrogenous detrital Re and Os, thereby providing more accurate and precise ages. A series of tests were performed, and the experimental data demonstrate the fundamental controls on spike-sample equilibrium and that the amount of detrital Re and Os incorporated into the system are subjected to the volumetric ratio of H2O2 to HNO3. The optimum method is a H2O2:HNO3 ratio of 5 to complete spike-sample equilibration, and to minimize the amount of detrital Re and Os in the system. A comparison of our new method with inverse aqua regia and CrO3-H2SO4 showed that the three techniques yield indistinguishable Re-Os results, suggesting complete spike-sample equilibrium was achieved by all of the digestion techniques. Moreover, the data show that our new technique leaches out the least amount of detrital Re and Os isotopes relative to conventional methods Thus, we propose the H2O2-HNO3 method may increase the precision and accuracy of Re-Os depositional ages of organic-rich sedimentary systems. (C) 2017 Elsevier B.V. All rights reserved

Risk Factor Analysis of Calcification in Aortic and Mitral Valves in Maintenance Peritoneal Dialysis Patients

Background/Aims: This study aimed to investigate potential risk factors for calcification in aortic and mitral valves in maintenance peritoneal dialysis (MPD) patients. Methods: We enrolled MPD patients who had undergone over 18 months of dialysis in our dialysis center, examined their cardiac valve calcification status by echocardiography, and recorded their biochemical data and dialysis-related indicators. These results were compared by logistic regression analyses to identify the risk factors associated with calcification in aortic and mitral valves. Results: Among the 117 enrolled MPD patients, 41 exhibited calcification in aortic or mitral valves, including 38 with aortic valve calcification (AVC) and 17 with mitral valve calcification (MVC); 14 of them had calcification in both aortic and mitral valves. Multivariate logistic regression analysis revealed that age (OR=1.965, p=0.01), diabetes history (OR=4.693, p=0.029), calcium-phosphorus product (OR=2.373, p=0.001) and prealbumin (OR=0.908, p=0.012) were independently related to AVC, whereas age (OR=3.179, p=0.023), calcium-phosphorus product (OR=6.512, p=0.001), prealbumin (OR=0.885, p=0.033), high-density lipoprotein (OR=19.540, p=0.011) and diabetes history (OR=6.948, p=0.038) were independently related to MVC. Conclusions The incidence of cardiac valve calcification in MPD patients is high, and the incidence of AVC is higher than MVC. Age, diabetes history, calcium-phosphorus product and hypo-prealbuminemia are independent risk factors for AVC, whereas age, calcium-phosphorus product and hypo-prealbuminemia are independent risk factors for MVC

2D Higher-Metal Nitride Nanosheets for Solar Steam Generation

Higher-metal (HM) nitrides are a fascinating family of materials being increasingly researched due to their unique physical and chemical properties. However, few focus on investigating their application in a solar steam generation because the controllable and large-scale synthesis of these materials remains a significant challenge. Herein, it is reported that higher-metal molybdenum nitride nanosheets (HM-Mo5N6) can be produced at the gram-scale using amine-functionalized MoS2 as precursor. The first-principles calculation confirms amine-functionalized MoS2 nanosheet effectively lengthens the bonds of Mo-S leading to a lower bond binding energy, promoting the formation of Mo-N bonds and production of HM-Mo5N6. Using this strategy, other HM nitride nanosheets, such as W2N3, Ta3N5, and Nb4N5, can also be synthesized. Specifically, under one simulated sunlight irradiation (1 kW m-2), the HM-Mo5N6 nanosheets are heated to 80 °C within only ≈24 s (0.4 min), which is around 78 s faster than the MoS2 samples (102 s/1.7 min). More importantly, HM-Mo5N6 nanosheets exhibit excellent solar evaporation rate (2.48 kg m-2 h-1) and efficiency (114.6%), which are 1.5 times higher than the solar devices of MoS2/MF.</p

Simultaneously increasing the hydrophobicity and interfacial adhesion of carbon fibres: a simple pathway to install passive functionality into composites

International audienceA common strategy to enhance the fibre-to-matrix adhesion of carbon fibres is to increase the surface polarity using extensive and harsh oxidation techniques. In this work, we use a novel and scalable strategy to significantly increase the hydrophobicity of carbon fibres without any sacrifice in the fibres' physical properties and demonstrate simultaneous increases to the fibre-to-matrix adhesion (59-216%). These findings contradict the commonly accepted paradigm of high fibre polarity correlating to increased interfacial adhesion. We demonstrate the ability to covalently modify the surface of carbon fibres through electrochemical reduction of nitroaryldiazonium salts to generate perfluorinated alkyl radicals. Surface modification was confirmed by XPS, ATRIR, and TEM. The surfaces produced are highly hydrophobic, though this may be mitigated through the reduction of nitro groups to amines, or increased through the accumulative effects of perfluoroalkyl chains and nitro groups (WCA ranges from 99.9 AE 0.4 up to 135.5 AE 0.2 , versus pristine fibre 98.4 AE 0.6). Hydrophobic fibres functionalized only with perfluoroalkyl groups were stable to both acidic (pH 1) and basic (pH 12) environments. All surface chemistries demonstrated comparable or improved interfacial shear strength and these results correlated well with calculated values of interfacial shear stress, determined via molecular dynamics simulations