Umbilical fissure vein, anatomical variation and potential surgical application.

BACKGROUND: The umbilical fissure vein (UFV) is a hepatic vein that travels within the umbilical fissure (or its proximity), providing venous drainage for hepatic segments 3 and 4. Its preservation carries a potential importance in extended right hemi-hepatectomy, left lateral segmentectomy and extended segment 2 resections. METHODS: Consecutive 1-mm slice thickness portovenous phase intravenous contrast computed tomography (CT) scans of the abdomen performed were retrospectively reviewed during the period of June 2019 to July 2019, with two independent investigators investigating the presence of UFV, its course, insertion and relation to the umbilical fissure. RESULTS: A total of 244 CTs were identified and 186 included. The UFV was identified on 72.8% of participants, 109 (81.4%) drained into the main left hepatic vein, while the remaining ones drained either from the main middle hepatic vein (16.4%) or the bifurcation between main left and middle hepatic vein (2.2%). The veins course lay 2 mm or less along the length of umbilical fissure in 39.5%, while 57.5% ran within 1 cm along the length of the umbilical fissure. CONCLUSION: Pre-operative identification of UFV could assist in operative planning. The vein can be used as a landmark in surgery and should be preserved in left lateral segmentectomy and extended right hepatectomy to avoid parenchymal congestion of remnant segments.

Tropical principal component analysis on the space of phylogenetic trees.

MOTIVATION: Due to new technology for efficiently generating genome data, machine learning methods are urgently needed to analyze large sets of gene trees over the space of phylogenetic trees. However, the space of phylogenetic trees is not Euclidean, so ordinary machine learning methods cannot be directly applied. In 2019, Yoshida et al. introduced the notion of tropical principal component analysis (PCA), a statistical method for visualization and dimensionality reduction using a tropical polytope with a fixed number of vertices that minimizes the sum of tropical distances between each data point and its tropical projection. However, their work focused on the tropical projective space rather than the space of phylogenetic trees. We focus here on tropical PCA for dimension reduction and visualization over the space of phylogenetic trees. RESULTS: Our main results are 2-fold: (i) theoretical interpretations of the tropical principal components over the space of phylogenetic trees, namely, the existence of a tropical cell decomposition into regions of fixed tree topology; and (ii) the development of a stochastic optimization method to estimate tropical PCs over the space of phylogenetic trees using a Markov Chain Monte Carlo approach. This method performs well with simulation studies, and it is applied to three empirical datasets: Apicomplexa and African coelacanth genomes as well as sequences of hemagglutinin for influenza from New York. AVAILABILITY AND IMPLEMENTATION: Dataset: http://polytopes.net/Data.tar.gz. Code: http://polytopes.net/tropica_MCMC_codes.tar.gz. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Core-dependent properties of copper nanoclusters: valence-pure nanoclusters as NIR TADF emitters and mixed-valence ones as semiconductors.

We report herein that copper alkynyl nanoclusters show metal-core dependent properties via a charge-transfer mechanism, which enables new understanding of their structure-property relationship. Initially, nanoclusters 1 and 2 bearing respective Cu(i)15 (C1) and Cu(i)28 (C2) cores were prepared and revealed to display near-infrared (NIR) photoluminescence mainly from the mixed alkynyl → Cu(i) ligand-to-metal charge transfer (LMCT) and cluster-centered transition, and they further exhibit thermally activated delayed fluorescence (TADF). Subsequently, a vanadate-induced oxidative approach to in situ generate a nucleating Cu(ii) cation led to assembly of 3 and 4 featuring respective [Cu(ii)O6]@Cu(i)47 (C3) and {[Cu(ii)O4]·[VO4]2}@Cu(i)46 (C4) cores. While interstitial occupancy of Cu(ii) triggers inter-valence charge-transfer (IVCT) from Cu(i) to Cu(ii) to quench the photoluminescence of 3 and 4, such a process facilitates charge mobility to render them semiconductive. Overall, metal-core modification results in an interplay between charge-transfer processes to switch TADF to semiconductivity, which underpins an unusual structure-property correlation for designed synthesis of metal nanoclusters with unique properties and functions.

Tropical Principal Component Analysis and Its Application to Phylogenetics.

Principal component analysis is a widely used method for the dimensionality reduction of a given data set in a high-dimensional Euclidean space. Here we define and analyze two analogues of principal component analysis in the setting of tropical geometry. In one approach, we study the Stiefel tropical linear space of fixed dimension closest to the data points in the tropical projective torus; in the other approach, we consider the tropical polytope with a fixed number of vertices closest to the data points. We then give approximative algorithms for both approaches and apply them to phylogenetics, testing the methods on simulated phylogenetic data and on an empirical dataset of Apicomplexa genomes.

Temperature-Mediated Template Release: Facile Growth of Copper(I) Mixed Ethynediide/Isopropylethynide Nanoclusters.

In the comproportionation reaction of CuII X2 and Cu0 with isopropylacetylene (iPr-C≡C-H), the ethynediide species C22- is generated via concomitant C-H/C-C bond cleavage of the iPr-C≡C-H precursor under moderate temperature to direct the formation of CuI mixed ethynediide/isopropylethynide nanoclusters (potentially explosive). The active ethynediide dianion C22- exhibits chameleon-like templating behavior to form C2 @Cum (m=6 (3, 4), 7 (2, 4), 8 (1)) central structural units for successive formation of {C22- ⊂Cu24 } (1, 2), {6 C22- ⊂Cu48 } (3), and {18 C22- ⊂Cu92 } (4) complexes. Bearing the highest C22- content, complex 4 features an unprecedented nanoscale Cu2 C2 kernel. Furthermore, 1-3 exhibit structure-controlled photoluminescence in the solid state.

Silver Thiolate Nano-sized Molecular Clusters and Their Supramolecular Covalent Frameworks: An Approach Toward Pre-templated Synthesis.

A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2 C2 using a C22- pre-templated approach. Herein, two prototype clusters Ag14 (SR)6 and CO3 @Agm (SR)10 (R=isopropyl, cyclohexyl or tert-butyl; m=18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely, Ag14 (S-iPr)6 (CO2 CF3 )8 ⋅(DMSO)6 (two polymorphic forms 1, 2) and [Ag14 (S-Cy)6 (CO2 CF3 )8 (DMSO)4 ]⋅(DMSO)3 (3), and a cluster-based metal-organic framework {Ag3 [Ag14 (S-iPr)6 (CO2 CF3 )11 (H2 O)3 CH3 OH]⋅(H2 O)2.5 }n (4) have been isolated and structurally characterized. Furthermore, increased acidity of the reaction mixture afforded three carboxylate-templated cluster based frameworks: a chain-like compound {[HN(CH3 )2 CO]⋅[CO3 @Ag18 (S-tBu)10 (NO3 )7 (DMF)4 ]⋅DMF}n (5), as well as two layer-type compounds, namely, {Ag[CO3 @Ag20 (S-iPr)10 (CO2 CF3 )9 (CO2 HCF3 )(CH3 OH)2 ]}n (6) and {Ag2 [CO3 @Ag20 (S-Cy)10 (CO2 CF3 )10 (CO2 HCF3 )2 (H2 O)2 ]⋅(H2 O)3 ⋅(CH3 OH)3 }n (7) exhibiting sql-net characteristics. It is demonstrated that the C≡C2- pre-template, which draws several Ag+ ions together to form the C2 @Agn entity, plays an indispensable role in the syntheses of these compounds. Furthermore, covalent linkage of these nano-sized silver thiolate clusters from one- to three-dimensions revealed enormous potential for the future development of silver cluster-based frameworks.

Decision trees for identifying predictors of treatment effectiveness in clinical trials and its application to ovulation in a study of women with polycystic ovary syndrome.

BACKGROUND: Double-blind, randomized clinical trials are the preferred approach to demonstrating the effectiveness of one treatment against another. The comparison is, however, made on the average group effects. While patients and clinicians have always struggled to understand why patients respond differently to the same treatment, and while much hope has been held for the nascent field of predictive biomarkers (e.g. genetic markers), there is still much utility in exploring whether it is possible to estimate treatment efficacy based on demographic and baseline variables. METHODS: The pregnancy in polycystic ovary syndrome (PPCOS) study was a prospective, multi-center, randomized clinical trial comparing three ovulation induction regimens: clomiphene citrate (CC), metformin and the combination of the two. There were 446 women who ovulated in response to the treatments among the entire 626 participants. In this report, we focus on the 418 women who received CC (alone or combined with metformin) to determine if readily available baseline physical characteristics and/or easily obtainable baseline measures could be used to distinguish treatment effectiveness in stimulating ovulation. We used a recursive partitioning technique and developed a node-splitting rule to build decision tree models that reflected within-node and within-treatment responses. RESULTS: Overall, the combination of CC plus metformin resulted in an increased incidence of ovulation compared with CC alone. This is particularly so in women with relatively larger left ovarian volumes (≥ 19.5 cubic cm), and a left ovarian volume <19.5 cubic cm was related to treatment outcomes for all subsequent nodes. Women who were older, who had higher baseline insulin, higher waist-to-hip circumference ratio or higher sex hormone-binding globulin levels had better ovulatory rates with CC alone than with the combination of CC plus metformin. CONCLUSIONS: Polycystic ovary syndrome (PCOS) is a phenotypically diverse condition. Both baseline laboratory and clinical parameters can predict the ovulatory response in women with PCOS undergoing ovulation induction. Without a priori hypotheses with regard to any predictors, the observation regarding left ovary volume is novel and worthy of further investigation and validation.