First Observation Of The Spin Rotational Structure Of The Hydroxymethyl Radical (h2coh) In The Ch2 Asymmetric Mode

Rotationally-resolved direct infrared absorption spectra of hydroxymethyl radical (H$_{2}$COH) in the CH$_{2}$ asymmetric mode (\nub{2}) were observed for the first time using the Boulder difference frequency generation infrared spectrometer. Hydroxymethyl radical was formed with chemical selectivity via the reaction of Cl radical with CH$_{3}$OH in a discharge slit-jet supersonic expansion. As a result of sub-Doppler linewidth and low rotational temperature, the \textit{b}-type rotational structure and spin-rotation splitting were fully resolved. In particular, tunneling splitting was observed due to the large-amplitude COH torsional mode. Because of the feasible permutation of hydrogens in the methylenic group, nuclear spin intensity alternation was given as: 3:1 for \textit{K$_{a}$}=even, odd in the 0$^{+}$ level, and 1:3 for \textit{K$_{a}$}=even, odd in the 0$^{-}$ level of the ground vibrational state. The assignments were confirmed rigorously by four-line ground state combination differences, which agreed within the experimental frequency uncertainty (10 MHz). The identified transitions were fit with a Watson \textit{A}-reduction Hamiltonian including the spin rotational interaction, leading to unambiguous determination of asymmetric top spectroscopic constants, as well as spin rotational constants ($\epsilon$$_{aa}$, $\epsilon$$_{bb}$, $\epsilon$$_{cc}$) for the first time

Artificial intelligence for detection of microsatellite instability in colorectal cancer-a multicentric analysis of a pre-screening tool for clinical application.

BACKGROUND Microsatellite instability (MSI)/mismatch repair deficiency (dMMR) is a key genetic feature which should be tested in every patient with colorectal cancer (CRC) according to medical guidelines. Artificial intelligence (AI) methods can detect MSI/dMMR directly in routine pathology slides, but the test performance has not been systematically investigated with predefined test thresholds. METHOD We trained and validated AI-based MSI/dMMR detectors and evaluated predefined performance metrics using nine patient cohorts of 8343 patients across different countries and ethnicities. RESULTS Classifiers achieved clinical-grade performance, yielding an area under the receiver operating curve (AUROC) of up to 0.96 without using any manual annotations. Subsequently, we show that the AI system can be applied as a rule-out test: by using cohort-specific thresholds, on average 52.73% of tumors in each surgical cohort [total number of MSI/dMMR = 1020, microsatellite stable (MSS)/ proficient mismatch repair (pMMR) = 7323 patients] could be identified as MSS/pMMR with a fixed sensitivity at 95%. In an additional cohort of N = 1530 (MSI/dMMR = 211, MSS/pMMR = 1319) endoscopy biopsy samples, the system achieved an AUROC of 0.89, and the cohort-specific threshold ruled out 44.12% of tumors with a fixed sensitivity at 95%. As a more robust alternative to cohort-specific thresholds, we showed that with a fixed threshold of 0.25 for all the cohorts, we can rule-out 25.51% in surgical specimens and 6.10% in biopsies. INTERPRETATION When applied in a clinical setting, this means that the AI system can rule out MSI/dMMR in a quarter (with global thresholds) or half of all CRC patients (with local fine-tuning), thereby reducing cost and turnaround time for molecular profiling

Grain Size Distribution, Coarse Fraction & Mineralogy of Sediments from Five Areas in the Equatorial & Southwest Pacific

173-179Preliminary results on the grain size distribution, coarse fraction and mineralogy of a limited number of deep-sea sediments from 4 areas in a N-S transect across the equatorial Pacific (Areas C, D, F and G) and I in the southwest Pacific (Area K) are reported. The sediments have been classified according to the Folk classification. Area C sediments are generally mud and in composition siliceous ooze to siliceous mud. The median grain size normally lies between 8.7 and 9.3 φ and the acid soluble (CaCO3) content between 3.1 and 15.9%. Sample 5 KG is a siliceous debris-bearing nanno/foram ooze with a carbonate content of 88.9%. Area D sediments are sandy mud and in composition siliceous debris-bearing nanno/foram ooze with ~n acid soluble content of 91.2%. The median grain size of these sediments is 8 φ. Area F sediments are sandy silt and in composition siliceous debris-bearing nanno/foram ooze with an acid soluble content of 95.5%. The median grain size of these sediments is 7.25 φ. Area G sediments are mud and in composition siliceous debris-bearing foram/nanno ooze with an acid soluble content of 58.6%. The median grain size of these sediments is 7.75 φ. Area K sediments are mud and in composition nanno/foram bearing red clay with an acid soluble content of 14.4%. The median grain size of these sediments is 8.95 φ. Very poorly sorted sediments are encountered in Areas D and F which lie near to the equatorial high carbonate zone and are characterised by high carbonate contents. The sorting of the sediments improves away from the equatorial region due to lower carbonate contents in the sediments. In the coarse fraction ( > 63 µm), radiolaria/siliceous matter predominates in the siliceous ooze sediments from Area C whereas foram/calcareous matter is the dominant constituent of the sediments from Areas D, F and G. Micronodules are the main constituents of the coarse fraction of the red clay sediments from Area K. Fish teeth are observed in sediments from Areas C and K while sediments from Areas D, F and G are devoid of fish teeth. The abundance of fish teeth may be related to carbonate contents of .the sediments which acts as a diluent. Mineralogically, Area C sediments are generally characterised by quartz and smectite with lesser amounts of chlorite + kaolinite, illite and plagioclase. Areas D, F and G sediments are dominated by calcite ( > 80%) with low percentages of quartz, smectite, chlorite + kaolinite, illite and plagioclase. Area K sediments are dominantly quartz and smectite. Chlorite + kaolinite, plagioclase, illite and calcite are present in moderately high percentages. Quartz, chlorite + kaolinite, illite and feldspar appear to be detrital and eolian in origin. Smectite may be authigenic in origin