Gastrointestinal bleeding risk factors in type A aortic dissection post-aortic arch replacement.

Background: Gastrointestinal bleeding (GIB) is a notable complication in patients diagnosed with aortic dissection (AD). We evaluated the outcomes and identified the risk factors associated with GIB in patients with AD. Methods: A retrospective case-control study was conducted on patients diagnosed with type A aortic dissection (TAAD) who underwent total aortic arch replacement (TAAR) at our institution from July 2021 to July 2023. Comprehensive clinical data, laboratory findings, and imaging results were meticulously gathered and analyzed to identify potential risk factors linked to GIB in this patient cohort. Results: Of the 198 AD patients who underwent TAAR, 38 (19.2%) developed postoperative GIB (GIB group), with a median interval of 7 days between surgery and bleeding onset. The GIB group exhibited significantly higher mortality (26.3% vs. 3.1%, P<0.001), prolonged intensive care unit (ICU) stay {15 [interquartile range (IQR), 8-25] vs. 7 (IQR, 5-12) days, P<0.001}, and extended duration of ventilation [168 (IQR, 120-372) vs. 71 (IQR, 34-148) hours, P<0.001] compared to the control group (n=160, 80.8%). Logistic regression analysis identified age >54 years [odds ratio (OR): 3.529], intraoperative red blood cell (RBC) transfusion >600 mL (OR: 3.865), and concomitant celiac trunk and superior mesenteric artery (SMA) hypoperfusion (OR: 15.974) as independent risk factors for GIB in AD patients. Conclusions: GIB subsequent to TAAR in AD patients is linked to adverse prognosis. Factors such as advanced age, extensive intraoperative transfusion, and gastrointestinal (GI) perfusion abnormalities may heighten the risk of GIB in this patient population.

Simo decoction versus domperidone suspension for post-pyloric spiral nasoenteric tube placement: A multicenter, randomized, non-inferiority trial.

BACKGROUND & AIMS: Leveraging prokinetics to facilitate trans-pyloric migration is a conventional strategy. However, due to restrictions on the use of domperidone suspension, oral prokinetics is relatively modest. The study aims to assess the effectiveness of simo decoction as an alternative to domperidone suspension in facilitating post-pyloric placement of spiral nasoenteric tubes. METHODS: A prospective, open-label, parallel, and non-inferiority randomized controlled trial was performed involving critically ill adults in 6 university hospitals in China between September 2017 and May 2019. Patients were randomly assigned to receive either simo decoction 20 ml q8h, or domperidone suspension 20 mg/20 ml q6h for 24 h. The primary outcome was procedure success defined as post-pyloric placement (spiral nasoenteric tubes reached the first portion of the duodenum or beyond confirmed by abdominal X-ray 24 h after tube insertion). RESULTS: Of 268 patients assessed for eligibility, 224 patients were enrolled and randomly assigned to the simo decoction group or the domperidone suspension group (n = 112 per group). The success rate of post-pyloric placement was 41.1% (46/112) in the simo decoction group, as compared with 47.3% (53/112) in the domperidone suspension group (a risk difference of -6.3%, 95% CI, -19.2% to 6.7%, adjusted risk difference -3.7%, 95% CI -16.3% to 9.0%), in the intention-to-treat analysis, crossing the prespecified margin of -10% for non-inferiority. There were no differences between groups in the success rates of post-D1 (reaching the second portion of the duodenum or beyond), post-D2 (reaching the third portion of the duodenum or beyond), post-D3 (reaching the fourth portion of the duodenum or beyond) and proximal jejunum placement, the incidences of any adverse events, length of ICU stay or mortality in ICU. CONCLUSIONS: Non-inferiority of simo decoction to domperidone suspension was not confirmed in facilitating post-pyloric placement of spiral nasoenteric tubes. Registration: The trial was registered with the Chinese Clinical Trial Registry at http://www.chictr.org.cn (registration number ChiCTR-INR-17011311).

Determination of boron content and isotopic composition in gypsum by inductively coupled plasma optical emission spectroscopy and positive thermal ionization mass spectrometry using phase transformation.

As a stable isotope, boron plays an important role in hydrogeology, environmental geochemistry, ore deposit geochemistry and marine paleoclimatology. However, there is no report of boron isotopic composition in gypsum. This is mainly confined to complete dissolution of Gypsum by water or acid. In this study, gypsum was converted to calcium carbonate (CaCO3) with ammonium bicarbonate(NH4HCO3) by two steps at 50°C. In every step, the mass ratio of NH4HCO3/CaSO4·2H2O was twice, and conversion rate reached more than 98%. Converted CaCO3 was totally dissolved with hydrochloric acid (the dissolution rate was over 99%). In order to overcome the difficulties of the matrix interference and the detection limit of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), we use Amberlite IRA 743 resin to purify and enrichment the boron at first, then eluting boron from the resin with 10mL 0.1mol/L hydrochloric acid at 75°C. The boron isotopic composition of natural gypsum samples was determined using positive thermal ionization mass spectrometry (P-TIMS). The boron isotopic composition of gypsum may be an excellent indicator for the formation environment.

Accurate and precise determination of boron isotopic ratios at low concentration by positive thermal ionization mass spectrometry using static multicollection of Cs2BO2+ ions.

A static double-collector system for accurate, precise, and rapid boron isotope analysis has been established by employing a newly fixed Faraday H3 and H4 cup enabling simultaneously collected Cs2BO2(+) ion beams (m/z = 308 and 309) on a Finnigan-MAT Triton thermal ionization mass spectrometer of boron (Triton B). The experimental result indicated that Cs2BO2(+) ion beams (m/z = 308 and 309) were simultaneously collected using a fixed Faraday H3 and H4 cup without using the "Zoom Quad" function and reduced accelerating voltage. Furthermore, the method enabled the measurement of samples containing as little as 20 ng of boron. An analysis of the National Institute of Standards and Technology standard reference material (NIST SRM) 951 standard showed external reproducibility (2RSD) of ±0.013‰, ± 0.013‰, and ±0.019‰ for 100, 50, and 20 ng of boron, respectively. The present method of static multicollection of Cs2BO2(+) ions is applicable to a wide field of boron isotopic research that requires high precision and accuracy to analyze samples with low boron concentrations, including pore fluids, foraminifera, rivers, rainwater, and other natural samples.

Precise determination of the absolute isotopic abundance ratio and the atomic weight of chlorine in three international reference materials by the positive thermal ionization mass spectrometer-Cs2Cl+-graphite method.

Because the variation in chlorine isotopic abundances of naturally occurring chlorine bearing substances is significant, the IUPAC Inorganic Chemistry Division, Commission on Isotopic Abundances and Atomic Weights (CIAAW-IUPAC) decided that the uncertainty of atomic weight of chlorine (A(r)(Cl)) should be increased so that the implied range was related to terrestrial variability in 1999 (Coplen, T. B. Atomic weights of the elements 1999 (IUPAC Technical Report), Pure Appl. Chem.2001, 73(4), 667-683; and then, it emphasized that the standard atomic weights of ten elements including chlorine were not constants of nature but depend upon the physical, chemical, and nuclear history of the materials in 2009 (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396). According to the agreement by CIAAW that an atomic weight could be defined for one specified sample of terrestrial origin (Wieser, M. E.; Coplen, T. B. Pure Appl. Chem.2011, 83(2), 359-396), the absolute isotope ratios and atomic weight of chlorine in standard reference materials (NIST 975, NIST 975a, ISL 354) were accurately determined using the high-precision positive thermal ionization mass spectrometer (PTIMS)-Cs(2)Cl(+)-graphite method. After eliminating the weighing error caused from evaporation by designing a special weighing container and accurately determining the chlorine contents in two highly enriched Na(37)Cl and Na(35)Cl salts by the current constant coulometric titration, one series of gravimetric synthetic mixtures prepared from two highly enriched Na(37)Cl and Na(35)Cl salts was used to calibrate two thermal ionization mass spectrometers in two individual laboratories. The correction factors (i.e., K(37/35) = R(37/35meas)/R(37/35calc)) were obtained from five cycles of iterative calculations on the basis of calculated and determined R((37)Cl/(35)Cl) values in gravimetric synthetic mixtures. The absolute R((37)Cl/(35)Cl) ratios for NIST SRM 975, NIST 975a, and ISL 354 by the precise calibrated isotopic composition measurements are 0.319876 ± 0.000067, 0.319768 ± 0.000187, and 0.319549 ± 0.000044, respectively. As a result, the atomic weights of chlorine in NIST 975, NIST 975a, and ISL 354 are derived as 35.45284(8), 35.45272(21), and 35.45252(2) individually, which are consistent with the issued values of 35.453(2) by IUPAC in 1999.

Emission mechanism of polyatomic ions Cs2Cl+ and Cs2BO2(+) in thermal ionization mass spectrometry with various carbon materials.

The emission behavior of polyatomic ions Cs(2)Cl(+) and Cs(2)BO(2)(+) in the presence of various carbon materials (Graphite, Carbon, SWNTs, and Fullerenes) in the ionization source of thermal ionization mass spectrometry (TIMS) has been investigated. The emission capacity of various carbon materials are remarkably different as evidenced by the obvious discrepancy in signal intensity of polyatomic ions and accuracy/precision of boron and chlorine isotopic composition determined using Cs(2)Cl(+)-graphite-PTIMS/Cs(2)BO(2)(+)-graphite-PTIMS methods. Combined with morphology and microstructure properties of four selected carbon materials, it could be concluded that the emission behavior of the polyatomic ions strongly depends on the microstructure of the carbon materials used. A surface-induced collision mechanism for formation of such kinds of polyatomic ions in the ionization source of TIMS has been proposed based on the optimized configuration of Cs(2)BO(2)(+) and Cs(2)Cl(+) ions in the gas phase using a molecular dynamics method. The combination of the geometry of the selected carbon materials with the configuration of two polyatomic ions explains the structure effect of carbon materials on the emission behavior of polyatomic ions, where graphite samples with perfect parallels and equidistant layers ensure the capacity of emission to the maximum extent, and fullerenes worsen the emission of polyatomic ions by blocking their pathway.

Effective elimination of organic matter interference in boron isotopic analysis by thermal ionization mass spectrometry of coral/foraminifera: micro-sublimation technology combined with ion exchange.

In order to better estimate the effectiveness of micro-sublimation technology on the elimination of organic matter interference during boron isotopic analysis, a series of improved experiments was carried out using simple apparatus. Recovery rates after micro-sublimation were measured for boric acid solutions with different B contents or different B/organic matter ratios. The improved micro-sublimation procedure combined with ion-exchange technology was then used to test natural samples (coral and foraminifera) for the separation of boron. Our results show that the time taken for 100% recovery of different amounts of B differed and that the proportions of B/organic matter within the natural organic matter have little effect on the relationship between the recovery rates of B and the micro-sublimation times. The experiments further confirm that the organic matter does indeed have an effect on boron isotope analyses by positive thermal ionization mass spectrometry and that the use of micro-sublimation can effectively remove interferences from the organic matter during boron isotopic analysis.

Major factors affecting the isotopic measurement of chlorine based on the Cs2Cl+ ion by thermal ionization mass spectrometry.

The factors that affect isotopic measurement of chlorine based on Cs2Cl+ ion by thermal ionization mass spectrometry were studied. Graphite is essential for the emission of Cs2Cl+ ion from CsCl. No Cs2Cl+ ions are detected in the absence of graphite on the filament. The emission of Cs2Cl+ ion and the measured 37Cl/35Cl ratio were affected by different varieties of graphite, the pH value of the sample solution, and impurities in the solution. High-precision isotopic measurement of chlorine based on Cs2Cl+ ion is achieved only by using graphite with a perfect crystal structure. The measured 37Cl/35Cl ratios were much higher, and even the emission of Cs2Cl+ ion becomes impossible when pH values of the sample solution were higher than 6, corresponding to the presence of excess Cs. The measured 37Cl/35Cl ratios were higher when SO4(2-) and NO3- anions were present. The results show that the measured 37Cl/35Cl ratios are weakly related to the amount of chlorine on filament in a range from 1 to 500 microg.