Piezoelectric Applications of Low-Dimensional Composites and Porous Materials.

Low-dimensional (LD) materials, with atomically thin anisotropic structures, exhibit remarkable physical and chemical properties, prominently featuring piezoelectricity resulting from the absence of centrosymmetry. This characteristic has led to diverse applications, including sensors, actuators, and micro- and nanoelectromechanical systems. While piezoelectric effects are observed across zero-dimensional (0D), one-dimensional (1D), and two-dimensional (2D) LD materials, challenges such as effective charge separation and crystal structure imperfections limit their full potential. Addressing these issues requires innovative solutions, with the integration of LD materials with polymers, ceramics, metals, and other porous materials proving a key strategy to significantly enhance piezoelectric properties. This review comprehensively covers recent advances in synthesizing and characterizing piezoelectric composites based on LD materials and porous materials. The synergistic combination of LD materials with other substances, especially porous materials, demonstrates notable performance improvements, addressing inherent challenges. The review also explores future directions and challenges in developing these composite materials, highlighting potential applications across various technological domains.

Ligand engineering to achieve synergistic properties in a 2D bilayer supertetrahedral chalcogenide cluster-based assembled material.

Incorporating functional organic linkers into supertetrahedral chalcogenolate cluster-based materials is an effective synthetic strategy to expand structural diversity and generate tunable optical and photoelectric properties arising from synergistic effects. Herein, a mixed ligand engineering approach was adopted to design a supertetrahedral cluster-based assembled material [(Cd6Ag4(SPh)16(TPPA)(BPE)0.5)·2DMF]n (denoted as SCCAM-3) with a 2D bilayer architecture and broader visible-light absorption. Interestingly, SCCAM-3 demonstrates a long-lived afterglow at 83 K and efficient photocatalytic activity for degrading tetracycline in water.

BL02, a phage against carbapenem- and polymyxin-B resistant Klebsiella pneumoniae, isolated from sewage: A preclinical study.

The emergence of Carbapenem-resistant Klebsiella pneumoniae (CRKP) represents a threat to public health. Polymyxin-B is generally considered a last-resort antibiotic. In this study, we isolated a carbapenem- and polymyxin-B resistant K. pneumoniae phage BL02 for the first time in Southwestern China and evaluated its biological characteristics and whole-genome sequence. Polymyxin-B resistant K. pneumoniae, (CK02), was isolated from the blood of a male with severe septic shock, and phage BL02 was screened and purified from the hospital sewage. BL02 could lyse 40 out of 46 CRKP isolates (86.96%) and has high activity in the pH range of 6-10 and the temperature range of 4-55 °C. The latency period of BL02 was about 10 min and the lysis period was about 50 min. The genome results showed that BL02 was a linear dsDNA with a total length of 175,595 bp and a GC content of 41.83%. A total of 275 ORFs were predicted and no tRNA, rRNA, drug resistance genes, or virulence genes were found in the genome. Phylogenetic analysis showed that BL02 belongs to the family Straboviridae. Treatment of infected mice with two antibiotics (tigecycline or ceftazidime/avibactam) resulted in 7-day survival rates of 28.57% and 42.86%, respectively. In contrast, the survival rate of mice in the single-dose BL02-treated group was 71.43%. In summary, this preclinical study isolated a phage capable of lysing polymyxin-B resistant K. pneumoniae and validated its safety and efficacy in an in vivo model, which provides a reference for further research on controlling MDR pathogens.

Emerging Prevalence and Clinical Features of Elizabethkingia meningoseptica Infection in Southwest China: A 9-Year Retrospective Study and Systematic Review.

Background: Elizabethkingia meningoseptica infections have gradually emerged as life-threatening nosocomial infections worldwide, accompanied by increasing incidence, multidrug resistance and poor outcomes. However, the epidemiology and clinical features of E. meningoseptica infection are still limited in mainland China. Methods: Patients with E. meningoseptica infections from 2011 to 2019 in southwestern China were retrospectively analyzed. The clinical features, infection patterns and outcomes were extracted from medical records and analyzed. A comprehensive systematic review was performed in accordance with PRISMA guidelines from conception to August 23, 2021. Results: Ninety-two patients were ultimately included, with the prevalence rapidly rising from 0 in 2011 to 0.19 per 1000 inpatients in 2019. A total of 93.48% of E. meningoseptica isolates were multidrug resistant, including 100% resistance to carbapenem. Furthermore, 75% of E. meningoseptica infections were concomitant with other pathogens. The mortality of our cohort was 36.96%, with risk factors for mechanical ventilation (OR=9.51, P=0.004), male sex (OR=0.27, P=0.031) and more concomitant pathogens. After propensity score matching, central venous catheters, exposure to carbapenem and antifungal drugs, and underlying tumors were associated with E. meningoseptica infection. Sixteen articles were also summarized, with reported mortality rates ranging from 11.0% to 66.6%. Blood and respiratory tract were the common sources. Piperacillin/tazobactam, trimethoprim/sulfamethoxazole, fluoroquinolone and minocycline were the most sensitive antibiotics. Inappropriate antibiotic treatment was the most commonly reported risk factor for mortality. Conclusion: Nosocomial infection with E. meningoseptica has become an emerging problem with high mortality in southwestern China. Inappropriate antibiotic treatment and central venous catheters are risk factors for infection and death and should receive adequate attention.

Synthesis, Biological Evaluation, and Molecular Docking Studies of Hydrazones as Novel Xanthine Oxidase Inhibitors.

A series of hydrazones, 2-cyano-N'-(4-diethylamino-2-hydroxybenzylidene)acetohydrazide (1), N'-(5-bromo-2-hydroxy-3-methoxybenzylidene)-3-chlorobenzohydrazide monohydrate (2·H2O), N'-(2-hydroxy-3-methylbenzylidene)-4-nitrobenzohydrazide (3), and N'-(2-hydroxy-3-trifluoromethoxybenzylidene)-4-nitrobenzohydrazide (4), were prepared and structurally characterized by elemental analysis, IR and 1H NMR spectra, and single crystal X-ray determination. Xanthine oxidase inhibitory activities of the compounds were studied. Among the compounds, 2-cyano-N'-(4-diethylamino-2-hydroxybenzylidene)acetohydrazide shows the most effective activity. Docking simulation was performed to insert the compounds into the crystal structure of xanthine oxidase at the active site to investigate the probable binding modes.

Tin-sulfur based catalysts for acetylene hydrochlorination.

In the present work, tin-sulfur based catalysts were prepared using Na2SO3 and (CH3SO3)2Sn and were tested in acetylene hydrochlorination. Based on the analysis of experiments results, the acetylene conversion of (CH3SO3)2Sn/S@AC is still over 90%after a 50 h reaction, at the reaction conditions of T = 200 oC, VHCl/VC2H2 = 1.1:1.0 and C2H2-GSHV = 15 h-1. According to the results of X-ray photoelectron spectroscopy (XPS), HCl adsorption experiments, and acetylene temperature programmed desorption (C2H2-TPD), it is reasonable to conclude that the interaction between Sn and S not only can retard the oxidation of Sn2+ in catalysts but also strengthen the reactant adsorption capacity of tin-based catalysts. Furthermore, results obtained from nitrogen adsorption/desorption and XPS proved that the CH3SO3- can effectively decrease the coke deposition of (CH3SO3)2Sn/AC and thus prolong the lifetime of (CH3SO3)2Sn/AC.

Different Infection Profiles and Antimicrobial Resistance Patterns Between Burn ICU and Common Wards.

Infection is the leading cause of complications and deaths after burns. However, the difference in infection patterns between the burn intensive care unit (BICU) and burn common wards (BCW) have not been clearly investigated. The present study aimed to compare the infection profile, antimicrobial resistance, and their changing patterns in burn patients in BICU and BCW. Clinical samples were analyzed between January 1, 2011, and December 31, 2019, in the Institute of Burn Research in Southwest China. The patient information, pathogen distribution, sources, and antimicrobial resistance were retrospectively collected. A total of 3457 and 4219 strains were detected in BICU and BCW, respectively. Wound secretions accounted for 86.6% and 44.9% in BCW and BICU, respectively. Compared with samples in BCW, samples in BICU had more fungi (11.8% vs. 8.1%), more Gram-negative bacteria (60.0% vs. 50.8%), and less Gram-positive bacteria (28.2% vs. 41.1%). Acinetobacter baumannii were the most common pathogen in BICU, compared with Staphylococcus aureus in BCW. S. aureus was the most frequent pathogen in wound secretions and tissues from both BICU and BCW. However, A. baumannii were the first in blood, sputum, and catheter samples from BICU. Overall, the multidrug-resistance (MDR) rate was higher in BICU than in BCW. However, the gap between BICU and BCW gradually shortened from 2011 to 2019. The prevalence of MDR A. baumannii and Klebsiella pneumonia significantly increased, especially in BCW. Furthermore, Carbapenem resistance among K. pneumoniae significantly increased in BICU (4.5% in 2011 vs. 40% in 2019) and BCW (0 in 2011 vs. 40% in 2019). However, the percentage of MDR P. aeruginosa sharply dropped from 85.7% to 24.5% in BICU. The incidence of MRSA was significantly higher in BICU than in BCW (94.2% vs. 71.0%) and stayed at a high level in BICU (89.5% to 96.3%). C. tropicalis and C. albicans were the two most frequent fungi. No resistance to Amphotericin B was detected. Our study shows that the infection profile is different between BICU and BCW, and multidrug resistance is more serious in BICU than BCW. Therefore, different infection-control strategies should be emphasized in different burn populations.

Safety and Efficacy of a Phage, kpssk3, in an in vivo Model of Carbapenem-Resistant Hypermucoviscous Klebsiella pneumoniae Bacteremia.

Antimicrobial resistance (AMR) is one of the most significant threats to global public health. As antibiotic failure is increasing, phages are gradually becoming important agents in the post-antibiotic era. In this study, the therapeutic effects and safety of kpssk3, a previously isolated phage infecting carbapenem-resistant hypermucoviscous Klebsiella pneumoniae (CR-HMKP), were evaluated in a mouse model of systemic CR-HMKP infection. The therapeutic efficacy experiment showed that intraperitoneal injection with a single dose of phage kpssk3 (1 × 107 PFU/mouse) 3 h post infection protected 100% of BALB/c mice against bacteremia induced by intraperitoneal challenge with a 2 × LD100 dose of NY03, a CR-HMKP clinical isolate. In addition, mice were treated with antibiotics from three classes (polymyxin B, tigecycline, and ceftazidime/avibactam plus aztreonam), and the 7 days survival rates of the treated mice were 20, 20, and 90%, respectively. The safety test consisted of 2 parts: determining the cytotoxicity of kpssk3 and evaluating the short- and long-term impacts of phage therapy on the mouse gut microbiota. Phage kpssk3 was shown to not be cytotoxic to mammalian cells in vitro or in vivo. Fecal samples were collected from the phage-treated mice at 3 time points before (0 day) and after (3 and 10 days) phage therapy to study the change in the gut microbiome via high-throughput 16S rDNA sequence analysis, which revealed no notable alterations in the gut microbiota except for decreases in the Chao1 and ACE indexes.

Synthesis, Crystal Structures and Catalytic Property of Dioxidomolybdenum(VI) Complexes with Tridentate Hydrazones.

New dioxidomolybdenum(VI) complexes with the formula [MoO2L(MeOH)], derived from N'-(5-chloro-2-hydroxy-benzylidene)-2-methylbenzohydrazide (H2L1) and N'-(3,5-dichloro-2-hydroxybenzylidene)-2-methylbenzohydrazide (H2L2) were prepared. Crystal and molecular structures of the complexes were determined by single crystal X-ray dif-fraction method. Both complexes were further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazones L1 and L2 coordinate to the MoO2 cores through the enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atoms in both complexes are in octahedral coordination. Catalytic properties for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant have been studied.

Syntheses, X-Ray Single Crystal Structures and Biological Activities of Cobalt(III) Complexes with Reduced Schiff Base Ligands.

A new mononuclear cobalt(III) complex, [Co(HL1)2]Cl (1), derived from the reduced Schiff base 2,2'-((ethane-1,2-diylbis(azanediyl))bis(methylene))diphenol (H2L1), and a new dinuclear cobalt(III) complex, [Co2(L2)2]∆2H2O (2), derived from the reduced Schiff base 6,6'-(2-hydroxypropane-1,3-diyl)bis(azanediyl)bis(methylene)bis(2-bromo-4-chlorophenol) (H2L2), were synthesized and characterized by infrared and electronic spectroscopy, and single crystal X-ray diffraction techniques. The ligands were synthesized first, and then bound to the Co(III) centre. Compound 1 contains a mononuclear [Co(HL1)2]+ cation and a chloride anion. The cationic moiety possesses crystallographic inversion center symmetry. Compound 2 contains a dinuclear [Co2(L2)2] molecule and two water hydrate molecules. The Co atoms in the complexes are in octahedral coordination. Both complexes showed potential antimicrobial activity.

Characterization and genome sequencing of a novel T7-like lytic phage, kpssk3, infecting carbapenem-resistant Klebsiella pneumoniae.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has spread globally and emerged as an urgent public health threat. Bacteriophages are considered an effective weapon against multidrug-resistant pathogens. In this study, we report a novel lytic phage, kpssk3, which is able to lyse CRKP and degrade exopolysaccharide (EPS). The morphological characteristics of kpssk3 observed by transmission electron microscopy, including a polyhedral head and a short tail, indicate that it belongs to the family Podoviridae. A one-step growth curve revealed that kpssk3 has a latent period of 10 min and a burst size of 200 plaque-forming units (pfu) per cell. kpssk3 was able to lyse 25 out of 27 (92.59%) clinically isolated CRKP strains, and it also exhibited high stability to changes in temperature and pH. kpssk3 has a linear dsDNA genome of 40,539 bp with 52.80% G+C content and 42 putative open reading frames (ORFs). No antibiotic resistance genes, virulence factors, or integrases were identified in the genome. Based on bioinformatic analysis, the tail fiber protein of phage kpssk3 was speculated to possess depolymerase activity towards EPS. By comparative genomics and phylogenetic analysis, it was determined that kpssk3 is a new T7-like virus and belongs to the subfamily Autographivirinae. The characterization and genomic analysis of kpssk3 will promote our understanding of phage biology and diversity and provide a potential strategy for controlling CRKP infection.

Lytic Bacteriophage Screening Strategies for Multidrug-Resistant Bloodstream Infections in a Burn Intensive Care Unit.

BACKGROUND Increasing antibiotic resistance and multidrug resistance (MDR) in patients with bloodstream infection (BSI) has resulted in treatment using bacteriophage. This study aimed to identify Gram-negative bacilli and Gram-positive cocci and antibiotic resistance in patients with BSI in a burn intensive care unit (BICU). The environment, including sewage systems, were investigated for the presence of lytic bacteriophage. MATERIAL AND METHODS Between January 2011 to December 2017, 486 patients with BSI were admitted to the BICU. Blood culture identified the main infectious organisms. Bacterial screening tests for antibiotic resistance included the D test and the modified Hodge test (MHT). Lytic bacteriophage was isolated from the environment. RESULTS In 486 patients with BSI, the main causative organisms were Gram-negative bacilli (64.6%), Gram-positive cocci (27.7%), and fungi (7.7%). The main pathogenic organisms that showed multidrug resistance (MDR) were Acinetobacter baumannii (26.0%), Staphylococcus aureus (16.8%), and Pseudomonas aeruginosa (14.2%). Bacteriophage was mainly isolated from Gram-negative bacilli. Screening of hospital and residential sewage systems identified increased levels of bacteriophage in hospital sewage. CONCLUSIONS The causative organisms of BSI and the presence of MDR in a hospital BICU were not typical, which supports the need for routine bacterial monitoring. Hospital sewage provides a potential source of bacteriophage for the treatment of MDR pathogenic bacteria.

Global Transcriptomic Analysis of the Interactions between Phage φAbp1 and Extensively Drug-Resistant Acinetobacter baumannii.

Acinetobacter baumannii is a growing threat, although lytic bacteriophages have been shown to effectively kill A. baumannii. However, the interaction between the host and the phage has not been fully studied. We demonstrate the global profile of transcriptional changes in extensively drug-resistant A. baumannii AB1 and the interaction with phage φAbp1 through RNA sequencing (RNA-seq) and bioinformatic analysis. Only 15.6% (600/3,838) of the genes of the infected host were determined to be differentially expressed genes (DEGs), indicating that only a small part of the bacterial resources was needed for φAbp1 propagation. Contrary to previous similar studies, more upregulated rather than downregulated DEGs were detected. Specifically, φAbp1 infection caused the most extensive impact on host gene expression at 10 min, which was related to the intracellular accumulation phase of virus multiplication. Based on the gene coexpression network, a middle gene (gp34, encoding phage-associated RNA polymerase) showed a negative interaction with numerous host ribosome protein genes. In addition, the gene expression of bacterial virulence/resistance factors was proven to change significantly. This work provides new insights into the interactions of φAbp1 and its host, which contributes to the further understanding of phage therapy, and provides another reference for antibacterial agents. IMPORTANCE Previous research has reported the transcriptomic phage-host interactions in Escherichia coli and Pseudomonas aeruginosa, leading to the detailed discovery of transcriptomic regulations and predictions of specific gene functions. However, a direct relationship between A. baumannii and its phage has not been previously reported, although A. baumannii is becoming a rigorous drug-resistant threat. We analyzed transcriptomic changes after φAbp1 infected its host, extensively drug-resistant (XDR) A. baumannii AB1, and found defense-like responses of the host, step-by-step control by the invader, elaborate interactions between host and phage, and elevated drug resistance gene expressions of AB1 after phage infection. These findings suggest the detailed interactions of A. baumannii and its phage, which may provide both encouraging suggestions for drug design and advice for the clinical use of vital phage particles.

Characterization and genome annotation of a newly detected bacteriophage infecting multidrug-resistant Acinetobacter baumannii.

A novel virulent bacteriophage, φAbp2, infecting multidrug-resistant (MDR) Acinetobacter baumannii was isolated from the wastewater of a sewage management centre at Southwest Hospital, China. Transmission electron microscopy and phylogenetic analysis revealed that φAbp2 belongs to the subfamily Peduovirinae. A one-step growth curve demonstrated that φAbp2 had a latent period of 15 min, a lysis period of 35 min, and a burst size of 222 particles per infected host cell. Moreover, φAbp2 showed a relatively broad host range in local A. baumannii, and it also exhibited tolerance over a wider range of thermal and pH conditions. Genomic sequencing revealed that φAbp2 has a circular double-stranded DNA genome with no sequence similarity to our previously isolated φAbp1. Eighty-eight putative open reading frames (ORFs) encoding 41 proteins of known function and 47 of unknown function were identified, and the G/C content was 37.84%. φAbp2 is a new member of the subfamily Peduovirinae of the family Myoviridae. Its genome sequence is very similar to that of the A. baumannii phage LZ35.

Synthesis, Crystal Structures and Antimicrobial Activity of Oxidovanadium(V) Complexes with Hydrazone and Pyrone Ligands.

A pair of oxidovanadium(V) complexes, [VOLL1] (1) and [VOLL2] (2), where L is the dianionic form of the hydrazone ligand N'-(5-chloro-2-hydroxybenzylidene)pivalohydrazide (H2L), L1 and L2 are the deprotonated forms of 3-hydroxy-2-methyl-4H-pyran-4-one (HL1; maltol) and 2-ethyl-3-hydroxy-4H-pyran-4-one (HL2; ethyl maltol), respectively, have been prepared and characterized by elemental analyses, IR and UV-Vis spectroscopy, and single-crystal X-ray crystallographic determination. The V atoms in the complexes are in octahedral coordination, with the hydrazone ligand coordinated to the V atoms through the phenolate O, imino N and enolate O atoms, and with the pyrone ligands coordinated to the V atoms through two O atoms. The effect of the compounds on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans was studied.

Panton-Valentine Leucocidin (PVL) as a Potential Indicator for Prevalence, Duration, and Severity of Staphylococcus aureus Osteomyelitis.

Staphylococcus aureus is the most common cause of the difficult-to-treat osteomyelitis (OM). To better diagnose and manage S. aureus OM, especially for severe and long duration cases, indicators for risk prediction and severity evaluation are needed. Here, 139 clinical S. aureus isolates from orthopedic infections were divided into OM group (60 isolates from 60 OM patients) and non-OM group (79 isolates from 79 non-OM patients). Molecular types, antimicrobial susceptibility, and virulence factor profiles were evaluated and compared between the two groups to identify potential indicators associated with the prevalence of S. aureus OM. Clinical manifestations and laboratory data were analyzed to identify indicators affecting OM duration and severity. We found that some sequence types were specific to OM infection. The pvl, bbp, and ebps genes were associated with S. aureus OM prevalence. The pvl, bbp, and sei genes were associated with relatively longer OM duration. Panton-Valentine leucocidin (PVL)-positive S. aureus OM presented more serious inflammatory responses. Our results emphasize the significance of PVL in affecting the prevalence, duration, and severity of S. aureus OM. Diagnosing and monitoring PVL-related S. aureus OM may help direct better prognosis and treatment of these patients.

Epidemiological characterization of Acinetobacter baumannii bloodstream isolates from a Chinese Burn Institute: A three-year study.

Acinetobacter baumannii infection is a serious threat to burn patients. Bacteremia due to A. baumannii is becoming the most common cause of mortality following burn. However, the epidemiology of A. baumannii causing burn-related bloodstream infections has rarely been reported. We retrospectively collected 81 A. baumannii isolates from the bloodstream of burn patients over a three-year period. Antibiotic susceptibility tests, the prevalence of antibiotic-resistant genes and sequence typing (ST) were conducted to characterize these strains. Most of the isolates showed an extensive drug-resistant phenotype. The resistance frequencies to imipenem and meropenem were 94% and 91%, respectively. The blaOXA-23-like gene, AmpC, IS-AmpC, PER and SIM are the five most prevalent resistant genes, and their prevalence rates are 93% (75/81), 86% (70/81), 73% (59/81), 73% (59/81) and 52% (42/81), respectively. The 81 isolates were grouped into 10 known and 18 unknown ST types, with ST368 (38%) being the most prevalent. Except for ST457 and four new types (STn2, STn6, STn11 and STn14), the remaining 23 ST types belonged to one clonal complex 92, which is most common among clinical isolate in China. The above results indicated that ST368 isolates possessing both the blaOXA-23-like gene and ampC gene were the main culprits of the increasing nosocomial A. baumannii infection in this study. More attention should be paid to monitoring the molecular epidemiology of A. baumannii isolates from burn patients to prevent further distribution. Such information may help clinicians with therapeutic decisions and infection control in the Burns Institute.

Epidemiology and resistance features of Acinetobacter baumannii isolates from the ward environment and patients in the burn ICU of a Chinese hospital.

Acinetobacter baumannii is an important opportunistic pathogen that causes severe nosocomial infections, especially in intensive care units (ICUs). Over the past decades, an everincreasing number of hospital outbreaks caused by A. baumannii have been reported worldwide. However, little attention has been directed toward the relationship between A. baumannii isolates from the ward environment and patients in the burn ICU. In this study, 88 A. baumannii isolates (26 from the ward environment and 62 from patients) were collected from the burn ICU of the Southwest Hospital in Chongqing, China, from July through December 2013. Antimicrobial susceptibility testing results showed that drug resistance was more severe in isolates from patients than from the ward environment, with all of the patient isolates being fully resistant to 10 out of 19 antimicrobials tested. Isolations from both the ward environment and patients possessed the ß-lactamase genes bla OXA-51, bla OXA-23, bla AmpC, bla VIM, and bla PER. Using pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), these isolates could be clustered into 4 major PFGE types and 4 main sequence types (ST368, ST369, ST195, and ST191) among which, ST368 was the dominant genotype. Epidemiologic and molecular typing data also revealed that a small-scale outbreak of A. baumannii infection was underway in the burn ICU of our hospital during the sampling period. These results suggest that dissemination of ß-lactamase genes in the burn ICU might be closely associated with the high-level resistance of A. baumannii, and the ICU environment places these patients at a high risk for nosocomial infection. Cross-contamination should be an important concern in clinical activities to reduce hospitalacquired infections caused by A. baumannii.

An Extension of BLANC to System Mentions.

BLANC is a link-based coreference evaluation metric for measuring the quality of coreference systems on gold mentions. This paper extends the original BLANC ("BLANC-gold" henceforth) to system mentions, removing the gold mention assumption. The proposed BLANC falls back seamlessly to the original one if system mentions are identical to gold mentions, and it is shown to strongly correlate with existing metrics on the 2011 and 2012 CoNLL data.

Scoring Coreference Partitions of Predicted Mentions: A Reference Implementation.

The definitions of two coreference scoring metrics- B3 and CEAF-are underspecified with respect to predicted, as opposed to key (or gold) mentions. Several variations have been proposed that manipulate either, or both, the key and predicted mentions in order to get a one-to-one mapping. On the other hand, the metric BLANC was, until recently, limited to scoring partitions of key mentions. In this paper, we (i) argue that mention manipulation for scoring predicted mentions is unnecessary, and potentially harmful as it could produce unintuitive results; (ii) illustrate the application of all these measures to scoring predicted mentions; (iii) make available an open-source, thoroughly-tested reference implementation of the main coreference evaluation measures; and (iv) rescore the results of the CoNLL-2011/2012 shared task systems with this implementation. This will help the community accurately measure and compare new end-to-end coreference resolution algorithms.