Bacterial aromatic polyketides, exemplified by anthracyclines, angucyclines, tetracyclines, and pentangular polyphenols, are a large family of natural products with diverse structures and biological activities and are usually biosynthesized by type II polyketide synthases (PKSs). Since the starting point of biosynthesis and combinatorial biosynthesis in 1984–1985, there has been a continuous effort to investigate the biosynthetic logic of aromatic polyketides owing to the urgent need of developing promising therapeutic candidates from these compounds. Recently, significant advances in the structural and mechanistic identification of enzymes involved in aromatic polyketide biosynthesis have been made on the basis of novel genetic, biochemical, and chemical technologies. This review highlights the progress in bacterial type II PKSs in the past three years (2013–2016). Moreover, novel compounds discovered or created by genome mining and biosynthetic engineering are also included. The following ketoreductases (KRs) and aromatases (AROs), along with oxygenases and in some cases transferases, function together to convert the poly-β-keto chain into the aromatic polyketide core. Finally, post-tailoring modifications composed of redox, group transfer, hydrolysis, and rearrangement reactions endow the polyketide core skeleton with structural diversities that contribute to potent therapeutic properties. Mechanistic studies of polyketide biosynthesis have made great progress in the past decade; however, because of emerging antibiotic and anticancer drug resistance, there is a need to unravel the chemical logic and molecular machinery involved in the biosynthetic pathway; this will form the basis of engineering natural product assembly lines to generate bioactive compounds that could lead to clinical candidates. In the past few years, quite a number of novel catalytic mechanisms and biosynthetic strategies have been discovered, and several biosynthetic pathways have been revealed. Additionally, a growing number of crystal structures of enzymes involved in type II polyketide biosynthesis have been elucidated, which not only contributes a lot to mechanistic characterization but also enables the study of enzymatic evolution at the structural level and provides structural diversities when combined with chemical synthesis.Type II polyketide biosynthesis usually begins by loading an α-carboxylated precursor, normally acetate, onto an acyl carrier protein (ACP), which is subsequently transferred to the active site of a ketosynthase (KS) and then undergoes iterative elongation using malonyl-coenzyme A (CoA) as extender units to afford a nascent poly-β-keto chain4. Tanget al. revealed that trioxacarcin biosynthesis may employ 2-methylbutyryl-CoA, a five-carbon precursor, as a starter unit; the13C6-L-isoleucine labeling study strongly supported the five-carbon precursor, although there was no direct evidence for the incorporation of 2-methylbutyryl-CoA  pathway in aurachin biosynthesis, was reported by Tsai’s group  that catalyzes the decarboxylation of methylmalonyl-CoA to generate propionyl-CoA, which then served as a starter unit during lomaiviticin biosynthesis 4. Tangryl-CoA 5. Addits group 6.7. The structure-based mutagenesis andin vitro functional assays revealed significant differences between StfQ and BexL. The C-term domain of StfQ functions as a dehydratase/ARO, catalyzing the first cyclization in the non-reducing system; on the contrary, the N-term domain of BexL in the reducing system, instead of the C-term in the non-reducing system, catalyzes the key reaction in the biosynthesis of aromatic polyketides  catalyze the regiospecific cyclization of the nascent polyketide intermediate to yield a defined polyketide product. AROs/CYCs can be separated into C7–C12 and C9–C14 AROs/CYCs based on the first ring cyclization patterns. Otherwise, according to their substrates, AROs/CYCs can be divided into two subclasses: “reducing” AROs/CYCs, which act on one carbonyl-reduced poly-β-keto, and “nonreducing” AROs/CYCs, which act on nonreduced poly-β-keto. Additionally, there are two types of AROs/CYCs – mono-domain and di-domain – on the basis of amino acid sequences. Three non-reducing mono-domain AROs/CYCs – TcmN (C9–C14), ZhuI (C7–C12), and WhiE (C9–C14) – have been reported by Tsai and co-workers in the past few years. Just recently, they presented the crystal structures of two di-domain AROs/CYCs: StfQ (non-reducing C7–C12) and BexL (reducing C7–C12)ketides . This wo2. A recent example of an atypical fourth ring cyclization in tetracycline biosynthesis was reported by Tang and co-workers, who demonstrated that SsfL2, conserved in all reported tetracycline biosynthetic gene clusters to date, is an ATP-dependent acyl-CoA ligase family enzyme8. SsfL2 catalyzes an ATP-dependent C1–C18 Claisen condensation to close the fourth ring to form the tetracyclic compound, which serves as the common precursor of tetracyclic natural products. It is proposed that SsfL2 directly adenylates the tricyclic carboxylic acid to facilitate the final carbon–carbon bond formation in the absence of CoA  species instead of the widely believed flavin-C4a peroxide, performs a dual oxidation of the highly reactive poly(β-carbonyl) and initiates a rare Favorskii-type rearrangement , XanO4, was demonstrated to catalyze epoxidation and, through Baeyer-Villiger (BV) dual reaction, transform an anthraquinone into a xanthone skeleton during the biosynthesis of xantholipin13. Significantly, homologous comparisons indicated that the XanO4-mediated reaction was supposed to be the general model of constructing a xanthone ring in polycyclic xanthone antibiotic biosynthesis  family flavin enzyme AlpK plays an essential role in preventing spontaneous dimerization and trimerization of the enzymatic product of AlpJ by introducing a C-5 hydroxyl group; another function of AlpK is supplying FADH2 through an atypical mechanism relative to the normal flavin adenine dinucleotide/flavin mononucleotide reductase -dependent MOs are another large and diverse superfamily of enzymes involved in natural product biosynthesis21, including the type II polyketide tailoring process. Recently, the Fe2+/α-KG-dependent enzyme SnoK was shown to catalyze C5''–C2 carbocyclization in nogalamycin biosynthesis  and the product mimic rabelomycin -dependent MO RdmB by Metsä-Ketelä and co-workers , the universal activating enzyme MoeZ, and sulfur-carrier proteins from primary metabolism function together with a similar mechanism in thiamine biosynthesis to afford 2-thiosugar . Luzhetskyy and co-workers discovered three new simocyclinones fromKitasatospora sp. andStreptomyces sp. NRRL B-24484, and the genetic accessibility of the producing strainKitasatospora sp. allows the revelation of the biosynthetic pathway of simocyclinones  with its substrates elucidated new information on the carbonyl reduction33. In addition, biosynthetic studies of kosinostatin, a complex polyketide from marineMicromonospora containing a γ-branched octose, revealed a PKS-II/nonribosomal peptide synthetase hybrid pathway using nicotinic acid and ribose as substrates , with significantly improved antibiotic activities compared with chelocardin, has been generated by introducing an aminotransferase (OxyD) and an acyltransferase (OxyP) from theStreptomyces rimosus otc gene cluster to a chelocardin-producing strain, where OxyP acts as a thiolase to prevent priming by acetate via the removal of the competing acetyl units, thus only a very low yield of CDCHD can be produced in the absence of OxyP  by heterologous expression of an eDNA-derived gene cluster inStreptomyces albus  also contribute to exploring new type II polyketides. By overexpression of a pathway-specific activator gene, chattamycins (members of the angucycline family of antibiotics) were isolated fromsis L10 40. Sequs albus 41,42. . albus 43. In aacteria  and reve46. Very recently, a non-enzymatic pyridine ring formation was found in the biosynthesis of the rubrolone tropolone alkaloids (47. Huang and co-workers reported the rubrolone biosynthetic gene cluster and demonstrated that a key biosynthetic intermediate can, in a non-enzymatic fashion, couple to ammonia or anthranilic acid to yield the aglycones of rubrolones. This non-enzymatic construction of an alkaloid pyridine ring provides an alternative strategy for pyridine ring formation in natural products.Several non-enzymatic strategies mediating the biosynthesis of type II polyketides have been reported. During jadomycin biosynthesis, the ring cleavage process results in a reactive aldehyde, which couples to a singular amino acid in the culture medium, non-enzymatically forming an imine intermediate that cyclizes into the jadomycin backbone. Using this unique non-enzymatic method and a follow-on amino derivatization, Jakeman and co-workers obtained several eight-membered ring-containing jadomycins and phenylalanine-analogue-derivatized jadomycins 45,46. kaloids 47. HuanIn the future, continuous efforts are still needed to characterize the assembly machinery and catalytic logic of aromatic polyketides at the genetic, structural, and biochemical levels. With the development of gene sequencing technology, combined with optimized heterologous expression systems, eDNA will be an essential source of novel aromatic polyketides. On the other hand, biosynthetic engineering mediated by gene combination from different pathways or activation of the cryptic gene clusters will continue to play an important role in developing new antibiotics with improved activities as well. Other approaches for exploring potent antibiotics also include non-enzymatic strategies and the combination of chemical synthesis and biological transformation.N5[O], flavin-N5-oxide; KR, ketoreductase; KS, ketosynthase; MO, monooxygenase; NADP, nicotinamide adenine dinucleotide phosphate; PKS, polyketide synthase; SAM, S-adenosyl methionine.ACP, acyl carrier protein; α-KG, α-ketoglutarate; ARO, aromatase; BV, Baeyer-Villiger; CDCHD, 2-carboxamido-2-deacetyl-chelocardin; CoA, coenzyme A; CYC, cyclase; eDNA, environmental DNA; Fl


AZOOR was first described by Gass in 1993 as a syndrome with rapid loss of one or more extensive zones of the outer retinal segments. It is characterized by photopsia, minimal funduscopic changes, and electroretinographic abnormalities. The efficacy of systemic steroids in treating AZOOR has been previously described and advocated by the concept of autoimmune retinopathy. However, the use of intravitreal of sustained-released steroid had not been mentioned to date.A 34-year-old man had sudden onset of central scotoma and photopsia in the left eye. His visual acuity continued deteriorating. The visual field defect demonstrated bilateral enlarged blind spots and altitudinal defects. Fluorescein angiography (FA) showed nonspecific retinal inflammation, and an electroretinogram (ERG) illustrated decreased amplitude of the b wave in both eyes. Optical coherence tomography (OCT) examinations revealed parafoveal loss of the photoreceptor inner/outer segment (IS/OS) junction. Therefore, acute zonal occult outer retinopathy (AZOOR) was diagnosed. Although his vision did not improve under the initial treatment of systemic corticosteroid and calcium channel blocker, remarkable improvement was noticed after the intravitreal injection(IVI) of Ozurdex, consistent with the recovered IS/OS junction disruption.We herein report a typical case of AZOOR, suggesting that the intravitreal injection of steroid may benefit in certain patients. AZOOR was first described by Gass in 1993 as a syndrome with rapid loss of one or more extensive zones of the outer retinal segments. It occurs predominantly in young women, characterized by photopsia, minimal funduscopic changes, and electroretinographic abnormalities affecting one or both eyes . The mosThe 34-year-old man was in good health until he failed to hit a ping-pong ball accurately one morning. Blackish dots appeared in the nasal upper visual field, and flashes blocked the vision in front of his left eye. He was myopic with −11.0 diopter (D) in the right eye (OD) and −15.0 in the left eye (OS), and he underwent LASIK surgery seven years ago. He visited our emergency department, where visual acuity (VA) revealed 20/20 (OD) and 20/32 (OS). No cells were noted at the anterior chamber (AC) or vitreous. His fundus seemed normal under dilated fundoscopy.On the next day, vision decreased significantly to 20/25 (OD) and 20/63 (OS). Visual field (VF) examinations demonstrated bilateral enlarged blind spots and altitudinal defects Fig. . FA showThe etiology of AZOOR remains controversial. An infectious viral process of the outer retina was suggested by Gass.  AutoimmuP = 0.007), and the mean MD at the final visit (−9.82 ± 10.74 dB) was significantly higher than the initial value (−13.66 ± 10.73 dB) (P = 0.02). Chen [Various treatments have been attempted in patients with AZOOR, including systemic corticosteroids, , 12, 24 On the other hand, ocular penetration of systemically administered drugs could have been restricted by the blood–retinal barrier, and the diluting effect of blood volume requires larger systemic doses . OzurdexStudies have demonstrated that visual functions in AZOOR patients improved spontaneously,  whereas


Implementation of whole exome sequencing has provided unique opportunity for a wide screening of causative variants in genetically heterogeneous diseases, including nonsyndromic hearing impairment. TRIOBP in the inner ear is responsible for proper structure and function of stereocilia and is necessary for sound transduction.Whole exome sequencing followed by Sanger sequencing was conducted on patients derived from Polish hearing loss family.TRIOBP pathogenic variants  causative of nonsyndromic, peri- to postlingual, moderate-to-severe hearing loss in three siblings from a Polish family. Typically, TRIOBP pathogenic variants lead to prelingual, severe-to-profound hearing loss, thus the onset and degree of hearing impairment in our patients represent a distinct phenotypic manifestation caused by TRIOBP variants. The pathogenic variant p.Gln268Leufs*610 disrupts the TRIOBP-4 and TRIOBP-5 isoforms (both expressed exclusively in the inner ear and retina) whereas the second pathogenic variant c.514G>T, p.Gly1672* affects only TRIOBP-5.Based on whole exome analysis, we identified two TRIOBP pathogenic variants. Although TRIOBP alterations are not a frequent cause of hearing impairment, this gene should be thoroughly analyzed especially in patients with a postlingual hearing loss. A delayed onset of hearing impairment due to TRIOBP pathogenic variants creates a potential therapeutic window for future targeted therapies.The onset and degree of hearing impairment, characteristic for our patients, represent a unique phenotypic manifestation caused by  GJB2 and GJB6 pathogenic variants more than 90 genes may be involved in HI pathogenesis (http://hereditaryhearingloss.org). Massive screening for causative variants within all protein-coding sequences is now available through whole exome sequencing (WES). Thus, a wide and unbiased search for pathogenic variants has become possible in many genetically heterogeneous diseases including HI [Two-thirds of early onset hearing impairment (HI) cases are due to genetic causes . After eTRIOBP (Trio- and f-actin-binding protein) (MIM 609761) was cloned in 2001 as TARA [ as TARA  and rena as TARA . Multipl as TARA , 6. Both as TARA . Such a ) MIM 60961 was clWhile TRIOBP-1 is widely expressed in different tissues, TRIOBP-4 and TRIOBP-5 was exclusively found in the adult inner ear and retina of both human and mice. In the inner ear TRIOBP-4 and TRIOBP-5 are expressed in stereocilia rootlets. Additionally, TRIOBP-4 is also localized along the whole length of stereocilia. Proper structure of the rootlets is essential for stereocilia rigidity and stiffness, thereby allowing normal process of sound transmission . In contTRIOBP pathogenic variant and establish a molecular diagnosis.We present here a family with isolated, perilingual to postlingual hearing loss with a recessive inheritance pattern, in which WES followed by direct Sanger sequencing allowed to identify one novel  and one known  TRIOBP Pedigree of the analyzed family is presented in Fig. GJB2 pathogenic variants and GJB6 deletions were excluded [DNA was isolated from peripheral blood by a standard salting out method . In the excluded . Libraryexcluded . All retexcluded , 14.TRIOBP were confirmed by Sanger sequencing with the use of dedicated primers (sequences available upon request) designed with the Primer 3 software [Potentially pathogenic variants in software  based onThe prediction of presence of nonsense-mediated mRNA decay (NMD) mechanism was performed with the Mutation Taster algorithm .http://exac.broadinstitute.org) (accessed 12/2016) and the in-house database of WES data from the Polish population (n = 1052) were used for the assessment of the population prevalence of the detected variants.Exome Aggregation Consortium (ExAC) (Proband (III.2), as well as the two affected siblings suffered from bilateral, non-syndromic HI. Apart from HI, all of the siblings were otherwise healthy. The age of HI onset was 12 y for the proband and 4,5 y and 3 y for the sibling III.1 and III.3, respectively. The proband was reported for an audiology consultation due to suspected hearing loss based on the parents’ observation that she listened to electronic devices on a loud volume. The reason for the audiology tests in the siblings was similar, but it cannot be excluded that the parents were more attentive in observing their younger son. All siblings suffered from moderate-to-severe HI, detailed audiometric data are presented in Fig. TRIOBP gene  both in a heterozygous form  introduces a 4-nucleotide deletion, which results in a frameshift, leading to shortening of the protein after the following 610 amino acids, while the c.5014G>T, p.Gly1672* variant  directly introduces a stop codon. Presence of two deleterious TRIOBP family suffering from perilingual or postlingual, moderate-to-severe HI. At the time of writing the onset and degree of HI, characteristic for our patients, represent a unique phenotypic manifestation caused by TRIOBP pathogenic variants. Most of the heretofore detected TRIOBP pathogenic variants are related to prelingual, severe-to-profound hearing loss. There is only one variant  assigned to postlingual onset of HI [TRIOBP variants but with a prelingual onset [TRIOBP family is the first one with a less severe HI in respect to both its onset and level.Here we report on the first et of HI  but in tal onset   and C-terminal coiled-coil. It is established that this protein directly binds and stabilizes the F-actin structures , presumaBoth variants detected in this study are predicted to result in a premature termination of translation . Shortened TRIOPB protein due to c.802_805deCAGG, p.Gln268Leufs*610 and c.5014G>T, p.Gly1672* variants is devoid of PH and coiled-coil domains crucial for the actin-binding process. There is also a possibility that the impaired TRIOBP transcripts are directed to degradation via the NMD mechanism, which was suggested by the Mutation Taster algorithm  confirmsTRIOBP gene are more prone to acoustic trauma. Thus, it seems essential for TRIOBP patients to rigorously avoid noise. On the other hand, a confirmed postnatal origin of HI provides a therapeutic window for targeted treatment in the future.A putative consequence of the described variants is a faulty or absent (via NMD) TRIOBP protein, presumably incapable to form stereocilia rootlets. In response to sound stimulation stereocilia dispossessed of their rootlets, deflect two-four times more intensely than the proper ones and are vulnerable to damage due to their floppiness . These fTRIOBP variants are not a frequent cause of HI. To date, 31 point alterations were described  should be included. Considering their low frequency in ExAC and our Polish in-house WES databases, point variants in the TRIOBP gene seem to be a rare but important cause of non-syndromic hearing loss. Given the high heterogeneity of the HI [GJB2 and GJB6 pathogenic variants, wide screening for causative mutations using next generation sequencing is becoming a standard with at least 18 targeted diagnostic HI panels described to date [n others . Taking  to date .TRIOBP pathogenic variant  causative of a unique phenotype. The presented variants disrupt isoform: TRIOBP-4, TRIOBP-5 and TRIOBP-5 respectively, which are expressed in the inner ear and form stereocilia rootlets. Although TRIOBP variants are not a frequent cause of hearing loss, this gene should be thoroughly analyzed also in patients with postlingual HI.Here we report one novel and one known


In this study, we describe a pathogenic missense mutation in POU4F3 in a four-generation Chinese family (6126) with midfrequency, progressive, and postlingual autosomal dominant nonsyndromic hearing loss (ADNSHL). By combining targeted capture of 129 known deafness genes, next-generation sequencing, and bioinformatic analysis, we identified POU4F3 c.602T>C (p.Leu201Pro) as the disease-causing variant. This variant cosegregated with hearing loss in other family members but was not detected in 580 normal controls or the ExAC database and could be classified as a “pathogenic variant” according to the American College of Medical Genetics and Genomics guidelines. We conclude that POU4F3 c.602T>C (p.Leu201Pro) is related to midfrequency hearing loss in this family. Routine examination of POU4F3 is necessary for the genetic diagnosis of midfrequency hearing loss. Hereditary nonsyndromic hearing loss is extremely heterogeneous. Mutations in the POU class 4 transcription factor 3 Most patients with ADNSHL show large variations in age of onset and degrees of variety. According to the affected frequency, the phenotypes are divided into low-frequency, midfrequency, high-frequency, and all-frequency hearing loss. Midfrequency hearing loss  is a rare form of hearing loss, and six associated genes have been reported to date: EYA4, TECTA, COL11A2, CCDC50, POU4F3, and SLC44A4  and c.602delT [p.Leu201fs]) ) , 22. We  POU4F3, in one Chinese family (6216) with ADNSHL. Younger patients in this family demonstrated midfrequency hearing loss with no additional clinical symptoms. Our results strongly suggest that this missense mutation is related to hearing loss in this family, which has a putative autosomal dominant inheritance pattern.In this study, we identified a novel missense mutation, c.602T>C in POU4F3 c. 602 T>C (p. Leu201Pro) through multiple deafness gene capture and next-generation sequencing. Notably, the hearing impairment of affected individuals in this family is mainly midfrequency. This specific audiogram should be considered in clinical genetic diagnosis and counselling. Therefore, screening for POU4F3 in ADNSHL patients with a postlingual, progressive, and U-shape audiogram is necessary for efficient genetic diagnosis and intervention.In summary, we describe the clinical and genetic characteristics of a Chinese family (number 6126) with postlingual ADNSHL caused by


Neurophysiological and neuroimaging data suggest that the brains of not only children but also adults are reorganized based on sensory inputs and behaviors. Plastic changes in the brain are generally beneficial; however, maladaptive cortical reorganization in the auditory cortex may lead to hearing disorders such as tinnitus and hyperacusis. Recent studies attempted to noninvasively visualize pathological neural activity in the living human brain and reverse maladaptive cortical reorganization by the suitable manipulation of auditory inputs in order to alleviate detrimental auditory symptoms. The effects of the manipulation of auditory inputs on maladaptively reorganized brain were reviewed herein. The findings obtained indicate that rehabilitation therapy based on the manipulation of auditory inputs is an effective and safe approach for hearing disorders. The appropriate manipulation of sensory inputs guided by the visualization of pathological brain activities using recent neuroimaging techniques may contribute to the establishment of new clinical applications for affected individuals. Cortical structures in the adult brain were previously considered to be nonplastic; however, cortical reorganization appears to occur even in the adult brain. Previous animal studies , 2 demonAdvances in neuroimaging techniques that visualize living human brain activity have revealed that the human adult brain may also be reorganized based on sensory inputs from the surrounding environment and behaviors. Cortical reorganization generally occurs in a direction that is preferable for fulfilling demands. For example, the skills of professional musicians , 5 and jMaladaptive reorganization in the human auditory cortex was discussed herein, and neurorehabilitation approaches for tinnitus –15 and sSubjective tinnitus is a phantom auditory sensation without any external sound source –20. It sHuman neuroimaging studies using positron emission tomography (PET) , 36, sinAuditory neural networks are composed of not only excitatory neurons but also inhibitory neurons, which contribute to sharpening frequency tuning by suppressing the excitatory activity of neighboring neurons  44–46].–46.44–46t-test indicated that the ratios of the N1m source strengths elicited in the BEN condition compared with those elicited in the silent condition were significantly greater for “non-tinnitus ear” than for “tinnitus ear” (t(6) = 3.16, p = 0.02, d = 1.20). As shown in Our previous study  used a pThe manipulation of sound inputs is one of the therapeutic approaches employed for tinnitus. Tinnitus retraining therapy (TRT) is one of the most widely used auditory stimulation approaches for tinnitus , 55. TRTIt is reasonable to assume that appreciated music catches a listener's attention and more clearly affects his or her brain functions than the broadband noise widely used in TRT. The enjoyment of music plays an important role in activating the reward system of the brain and leads to effective reorganization in the human auditory cortex , 63. A pTinnitus patients were assigned to one of two groups. Participants in the “target” group performed TMNMT; they listened to notched music that contained a constant frequency notch of one octave width centered at the individual tinnitus frequency. Participants in the “placebo” group listened to notched music that contained one octave moving notch sparing the tinnitus frequency octave. Over the course of the study, we recorded subjective tinnitus loudness and auditory-evoked responses elicited by each participant's tinnitus frequency TS. We demonstrated that pathological alterations in the inhibitory system appeared to occur in the auditory system of tinnitus patients in the aforementioned study . TMNMT mHearing aids are devices that amplify sound signals in order to compensate for hearing loss. It is widely known that the perception of tinnitus is often accompanied by sensorineural hearing loss. Therefore, the neural activity elicited by auditory signals amplified by the hearing aid may induce preferable reorganization in the auditory cortex and reduce the perception of tinnitus. However, clinical evidence to show that hearing aids suppress the perception of tinnitus is still limited . Since tSudden sensorineural hearing loss (SSHL) is an idiopathic condition characterized by the rapid loss of hearing without a clear pathological cause and is often accompanied by tinnitus symptoms . HoweverWe focused on this maladaptive cortical reorganization initiated by SSHL and assumed that the prevention of plastic changes associated with SSHL is beneficial for hearing recovery , 17. In d = 0.086). However, they differed in the 2nd (d = 0.642) and 3rd (d = 1.051) examinations. Participants in the “target” group recovered significantly better than those in the “placebo” group.Treatment outcomes were evaluated by comparing the hearing threshold levels of the two SSHL groups. One group was the “control” group that received SCT, while the other group was the “target” group that received CIST in combination with SCT. The mean threshold differences between the hearing loss and healthy ears were not significantly different between groups before starting the treatments . This finding indicated that cortical plastic changes occurred in the auditory cortex of SSHL patients, as reported previously [d = 1.16; N1m: d = 1.17) and 3rd examinations , similar to normal-hearing individuals. CIST extensively activated auditory neurons corresponding to the affected ear, while neural activity corresponding to the intact ear was reduced due to the ear plug. CIST appeared to promote the recovery of neural activity related to the hearing loss ear and disturb the progression of maladaptive cortical reorganization. Therefore, the addition of safe and cost-effective CIST to routine corticosteroid treatments appears to be beneficial for SSHL patients.Moreover, we measured the neural responses elicited by a monaural sound stimulation in SSHL patients in the “target” group. In order to assess the degree of plastic changes in hemispheric asymmetry –77, we ceviously –77. HowePrevious neurophysiological studies revealed that the auditory cortex may be reorganized based on auditory inputs, even in the adult brain. The utilization of previous findings on cortical plasticity induced by the manipulation of sensory inputs for the development of neurorehabilitation approaches appears to be effective for reducing or preventing maladaptive cortical plasticity and improving the quality of life of individuals with tinnitus , 14 and


Chlamydia strains were investigated based on the pipeline employed in HGTree database constructed in our recent study. Tree reconciliation method was applied in order to calculate feasible HGT events. Following initial detection and an evaluation procedure, evidence of the HGT was identified in 548 gene families including 42 gene families transferred from outside of Chlamydiae phylum with high reliability. The donor species of inter-phylum HGT consists of 12 different bacterial and archaeal phyla, suggesting that Chlamydia might have even more various host range than in previous reports. In addition, each species of Chlamydia showed varying preference towards HGT, and genes engaged in HGT within Chlamydia and between other species showed different functional distribution. Also, examination of individual gene flows of niche-specific genes suggested that many of such genes are transferred mainly within Chlamydia genus. Our results uncovered novel features of HGT acting on Chlamydia genome evolution, and it would be also strong evidence that HGT is an ongoing process for intracellular pathogens. We expect that the results provide more insight into lineage- and niche-specific adaptations regarding their infectivity and pathogenicity.Recent comparative genomics studies have suggested that horizontal gene transfer (HGT) is one of the major processes in bacterial evolution. In this study, HGT events of 64  Chlamydiae are a phylum of Gram-negative, obligate intracellular bacteria. They consist of four validly described groups  and five additional Candidatus families  [Waddila, Parachlamydia, and Simkania families have been detected as symbionts of protozoa and emerging pathogens causing infections in humans and animals, and Chlamydiaceae family includes 11 species capable of infecting mainly humans and a wide range of animal species [Chlamydiaceae family especially has significant impacts on human and animal health worldwide as it is successfully evolved to inhabit a wide spectrum of eukaryotic hosts, comprising from protozoa to placental mammals. The continuing discovery of new species infecting novel hosts and expanding host ranges of known species indicate importance of niche-specific gene acquisitions in Chlamydia [diaceae) . Waddila species , 3. Chlahlamydia .Chlamydia is largely unknown, but previous laboratory works have reported that HGT and subsequent recombination can occur after co-infection within host body [Chlamydia is possible as well [Chlamydia had been considered unlikely. It has only recently become obvious that Chlamydia genomes contain full gene sets necessary for HGT [C. trachomatis strains in which it was discovered that they actively swap DNA even with strains infecting different parts of the body, and the recombination was not restricted to few “hotspots” [C. psittaci genomes as well [Bacteria exchange their genetic information via horizontal gene transfer (HGT), and it has been considered to be one of a major driving force in the microbial evolution, with gene mutation , 6. Whilost body , 10. Dis as well . Traditi for HGT . Additiootspots” . Recent  as well .Chlamydia species. In this study, we analyzed sets of homologous genes from 64 chlamydial strains from 8 different species and their homologs in 2,407 other prokaryotes using the pipeline employed in our previous study, HGTree database [Chlamydiae and between Chlamydiae and non-chlamydial prokaryotes. HGTree is a comprehensive resource providing all feasible genome-wide HGT information for completely sequenced genomes of 2,472 prokaryotes  by means of phylogenetic tree reconciliation method [Chlamydiae, in order to improve the accuracy of the identification, we additionally evaluated the reliability of each potential candidate HGT events and mapping assignments using RAxML [Comparative genome analysis in many bacterial and archaeal studies have provided new insights into evolutionary history by exploring remnants of HGT events , 16. In database  to initing RAxML  and RANGng RAxML .Chlamydia by enabling this massive computation. We identified numerous feasible HGT events that has occurred in evolutionary lineages of Chlamydia. Donor organisms external to the Chlamydiae phylum were examined to have insights into the ecology of Chlamydia. We also examined gene flows of individual genes associated with chlamydia’s survival strategies in the host cell. We expect that the results presented in this work could explain how HGT have impact on niche- and lineage-specific evolution of Chlamydia.Tree reconciliation method is generally considered to be more powerful and sensitive in detecting HGT than distance-based methods , but it Chlamydia abortus, Chlamydia pecorum, Chlamydia psittaci, Chlamydia caviae, Chlamydia pneumoniae, Chlamydia felis, Chlamydia trachomatis, Chlamydia muridarum). The list of 64 analyzed strains is presented in the We used 64 completely sequenced chlamydial genomes representing 8 different species from the HGTree database for analysis  [To obtain HGTs with high reliability, additional analysis was applied following preliminary HGT detection with HGTree. Using RAxML , we recoer. 1.6)  after ther. 1.6)  was appler. 1.6) . FurtherDetected genes were assigned to the NCBI clusters of orthologous group (COG) catalogue . COGnizeChlamydia for every gene family. It appeared that HGT has favorably occurred between species in the Chlamydiae phylum, but there was also a number of genes derived from organisms outside of the phylum. These organisms belong to 59 different genera, covering 12 bacterial and archaeal phyla which include a wide spectrum of life style  tract of mammals. For example, ribose-phosphate pyrophosphokinase gene was transferred from Ureaplasma parvum which inhabit genital areas (SV: 1.0), and Enterococcus faecium transferred gene encoding ABC transporter family protein to C. psittaci (SV: 1.0). In previous study, it was discovered that not only Chlamydia can efficiently infect the GI tract of all hosts, including humans, but GI tract can also act as reservoir sites for chlamydial persistent infection [Although many of donor organisms such as nfection , 30. It nfection .Caldilinea aerophile (SV: 0.97), and gene encoding MiaB-like tRNA modifying enzyme was transferred from Thermanaerovibrio acidaminovorans DSM 6589 residing terrestrial environments (SV: 1.0). The mechanisms by which gene transfer of Chlamydia occurring is still unclear. A number of phages required for transduction were discovered and DNA transfers were observed after host co-infection of multiple strains in many studies [Chlamydiae phylum is considered as a group of successful parasites that have an extremely broad host range and distributed ubiquitous in nature. There have been only four families  discovered within the phylum which can grow in natural hosts like amoebae [Chlamydia may have even more various host range than we have thought and potentially exchange genes in as yet unknown natural host. It also suggests the hypothesis that there may exist a novel gene transfer mechanism enabling Chlamydia to exchange genes with free-living organisms.In addition to bacteria residing in human or animal body sites, we observed a big proportion of environmental donor species which inhabit aquatic or terrestrial habitats . For insle SV: 0.7, and ge studies . Chlamyd amoebae . However amoebae , 32, 33.Chlamydiae. Further examination of the 701 HGT-acquired genes with RAxML and RANGER-DTL 2.0 resulted in 548 putative genes including 42 non-Chlamydia originated genes with high reliability. The percentage of received genes was markedly variable across the species, being more than threefold greater in C. felis lineage , C. abortus lineage , and C. caviae lineage  than in C. trachomatis (8.15~9.66%)  . The gre5~9.66%) . In cont5~9.66%) . These rC. felis and C. abortus genome displayed the highest ratio of HGT genes in all the species, with 30.1% and 27.4% of total genes, respectively. C. abortus is the most recently diverged species which mainly responsible for enzootic abortion in sheep and cattle [C. trachomatis recombinants under antibiotic pressure [C. abortus can be explained as the result of ongoing adaptation to a new pathogenic lifestyle in placenta. In contrast, all of the C. trachomatis lineages show relatively low ratios, with an average of 9.08% of genes transferred. Possible explanation for this phenomenon is that C. trachomatis has very long evolutionary history since its divergence from the other Chlamydia approximately 6 million years ago [Chlamydia that infect across multiple host species with histories of frequent host species jumps [C. trachomatis has human beings as its exclusive natural host. Nevertheless, they are successfully adapted intracellular pathogens, which infections are among the most common of all human bacterial infections as it is a leading cause of sexually transmitted infection and blindness worldwide [C. trachomatis infecting phages detected may have impacts on the low ratio of HGT [As mentioned above, the d cattle . There id cattle . In a repressure . It is apressure . In thispressure , on the pressure . Therefoears ago , and unles jumps , 43, C. orldwide , 45. In o of HGT .Chlamydia and test whether transferred gene sets of each lineage are varied across functional pathways. In our analysis, variation in the number of transferred gene sets between lineages was quite similar across pathways, in most lineages, carbohydrate, nucleotide, and cofactor metabolism exchanged most abundantly  and to C.psittaci M56 (SV: 1.0) separately. The tryptophan biosynthesis pathway is necessary for survival of Chlamydia since host restricts chlamydial growth by degrading tryptophan as a defense mechanism [Chlamydia species possesses different level of functional gene sets of tryptophan biosynthesis pathway [TyrP gene encoding tyrosine/tryptophan transport protein was transferred within Chlamydia genus . However, phylogenetic incongruence suggested that TrpC of C. pecorum E58, C. felis Fe/C-56, and C. caviae GPIC were might have been transferred from Coxiella burnetti dugway 5J108-111 strain, another obligate intracellular pathogen of humans and animals (SV: 1.0). TrpC encodes indole-3-glycerol phosphate synthase which is necessary in the fourth step of tryptophan biosynthesis pathway. It was previously proposed that Coxiella burnetti acquired trp operon from simkania negevensis, a bacterium belonging to the Chlamydiae phylum [Add) associated in purine ribonucleotide biosynthesis pathway .Bacterial evolution is largely dependent on the ability to adapt and colonize specific niches. Gene transfers of virulence-related genes may affect the pathogenesis of specific ifestyle , there iifestyle . Presencmportant . We founechanism . Each Ch pathway . Among te phylum . Putativ pathway , althougmportant . AccordiChlamydia displays a unique biphasic developmental cycle. At all stages of infection, interactions between the Chlamydia and its host are essential, and they translocate different types of virulence effector proteins into host cytoplasm which are used for manipulation of host cellular functions [Chlamydia. Among the genes encoding structural components of the T3SS apparatus, there were evidences for intra-genus HGT in 5 genes . Among the effector proteins that are used for manipulation of host cell immune response, EEA1, Cap1, CPAF, Tsp, and pGP6-D appear to have histories of HGT only with other Chlamydia.unctions . Like viChlamydiaceae has been featured in many comparative genomics studies in recent few years [Chlamydia genus. It suggests that intra-genus HGT may have been a major mechanism for the acquisition of determining factors of infection in Chlamydia. This discovery reflect that virulence related genes circulate among Chlamydia which may facilitate speciation event and new strain emergence. In microbial pathogens, virulence genes are particularly important determinants of host and tissue range [Chlamydia genome evolution and proposed an expansion of current understanding of Chlamydia ecology. More insights into HGT mechanism of Chlamydia will come from future laboratory experiments.HGT among ew years , 14, 56.ue range , and traS1 FigAdd gene. (B) is the gene tree of Add gene. Phylogenetic difference between the gene tree and the species tree indicate that Add gene inferred to have undergone one or more HGT events. The tree reconciliation method detected 3 putative HGT events in Chlamydia. The species highlighted with color red indicate the organisms participated in the events. Arrows depict the HGTs between the organisms. Support values are shown near to the corresponding HGTs which indicated by arrows.(A) is the species tree of (EPS)Click here for additional data file.S1 Table(XLSX)Click here for additional data file.


Decision-making about the expected value of an experience or behavior can explain hearing health behaviors in older adults with hearing loss. Forty-four middle-aged to older adults (68.45 ± 7.73 years) performed a task in which they were asked to decide whether information from a surgeon or an administrative assistant would be important to their health in hypothetical communication scenarios across visual signal-to-noise ratios (SNR). Participants also could choose to view the briefly presented sentences multiple times. The number of these effortful attempts to read the stimuli served as a measure of demand for information to make a health importance decision. Participants with poorer high frequency hearing more frequently decided that information was important to their health compared to participants with better high frequency hearing. This appeared to reflect a response bias because participants with high frequency hearing loss demonstrated shorter response latencies when they rated the sentences as important to their health. However, elevated high frequency hearing thresholds did not predict demand for information to make a health importance decision. The results highlight the utility of a performance-based measure to characterize effort and expected value from performing tasks in older adults with hearing loss. Thus, examining the degree to which individuals value speech in different listening conditions can help explain hearing health behaviors. Here we describe the development of a web-based visual task for predicting hearing health behaviors that considers communication value based on how hard people will work to make a decision in a communication scenario.Older adults often report increased effort and fatigue when trying to understand speech, especially in challenging listening conditions. These difficulties persist even after accounting for audibility. Listening effort has been characterized as the tradeoff between the subjective value of understanding speech and the cost of implementing control7. Questionnaires and dual-task measures have been used to characterize this effort. For example, the NASA Task Load Index questionnaire was used to show that older adults experienced significantly less perceived effort during consonant recognition when the stimuli were amplified by hearing aids compared to when the stimuli were not amplified8. These measures do not typically characterize the value in performing the task, however, which may affect the subjective experience of effort9. The Hearing Handicap Inventory for the Elderly (HHIE) indirectly measures value by asking questions about changes in potentially valuable experiences and activities, but it does not explicitly measure value from listening experiences.Extracting meaning from degraded stimuli can be costly or effortful11, reduced cognitive function12, and increased illness13 related to elevated listening effort2 would increase the cost of listening to speech. The value that a listener experiences from a hearing-aid may diminish if there are minimal reductions in listening effort with hearing-aid use10. Thus, hearing-aid satisfaction can be influenced by the expected versus actual performance of hearing-aids17, which is consistent with the suggestion that patients who are skeptical of hearing-aid benefit are less likely to own hearing-aids18. Conversely, people who are willing to invest more time acclimating to their hearing-aids are more likely to experience satisfaction with their aid20.Objective and quantitative measures of communication value are important because value-based decision-making can explain multiple findings in the hearing literature. The increased fatigue22 measures value using two-alternative forced choice questions. People choose between smaller immediate rewards versus larger delayed rewards . Holding the actual reward value constant, people are more likely to choose the immediate reward as the waiting time increases22. This delay or temporal discounting demonstrates that the propensity to choose a reward decreases as the cost of a behavior  increases relative to its benefit . The MCQ has been effective in predicting behavior for health-related conditions26, in part because delay discounting characterizes the subjective value of a future reward. Thus, delay discounting may be sensitive to how much older adults with hearing loss will value future benefit from an aid9 and affect the decision to obtain a hearing-aid. Delay discounting may also be sensitive to how long older adults are willing to wait for hearing-aid benefit, which could affect hearing-aid satisfaction. In the context of experimental tasks, listeners who discount the value of a delayed reward would be expected to spend less time performing tasks28.Behavioral economic approaches provide explicit characterization of the expected value from a given behavior. For example, the classic Monetary Choice Questionnaire (MCQ)29. The value of a reward can be measured by observing the consumption (demand) of a reward as a function of effort, i.e. cost30. When value is measured with this method, an individual who displays a high value for a reward is sometimes said to have a high demand for that reward31.Like delay discounting, effort discounting involves a reduced propensity to choose a reward as cost increases, but cost is effort exertion rather than delay length32). Prior work has included health-based rewards to assess effort discounting in younger and older adults33 and hypothetical scenarios  are commonly used for discounting studies because they can predict real-life discounting measures34.Here we defined communication value as the demand for information in a hypothetical health care listening scenario that we reasoned would be relatable for most people . This design was guided by paradigms that assess the degree to which the consumption of a reward  changes with increasing cost Participants were asked to decide if sentences from an administrative assistant or surgeon would be “Important” to their health . The sentences were presented in visual noise across different signal-to-noise ratios (SNR) to approximate the experience of listening in a noisy environment. We measured the frequency with which people viewed or re-glimpsed the briefly presented stimuli (875 ms) before making a health importance decision. They could also decide to quit a trial before making a health importance decision if they did not think it was possible to make a decision, particularly for sentences in low SNR conditions. This design allowed for the estimation of communication value for two speaker conditions with a different likelihood of health importance, where value was defined as the frequency of re-glimpsing the sentences with decreasing SNR.37. We also note that visual tasks have been used previously with success to study hearing39. In addition, discounting measures are generally considered to characterize relatively stable traits41, including temperament42, and general cognitive function43. The relation with cognition appears to be influenced, at least in part, by the function of pre-frontal cortex that integrates information from different modalities to guide behavior44. Thus, discounting measures of a domain general function obtained with visual stimuli would be expected to relate to audiologic measures.The Communication Value Task was designed with visual stimuli rather than auditory stimuli so that it could be used to study listeners with a wide range of hearing loss without concerns about audibility of the stimuli affecting the measures. Like speech recognition, reading requires word identification and working memory abilities to understand the meaning of sentences as they unfold over time40, delay discounting can be relatively higher in older compared to middle-aged adults45. Changes in discounting could be due, at least in part, to age-related hearing loss47 and increased hearing handicap that reflects a diminished quality of life for older adults. We predicted that participants with greater delay discounting would demonstrate less demand for information to make a health importance decision because this behavior would increase the length of each trial and the task. The results described below show that hearing loss was associated with an increased expectation or bias to decide that information was important, but this behavior was not aligned with the demand for information to guide that decision.Given the relatively limited extent of work on discounting in people with hearing loss, the focus of this project was to determine the extent to which to the Communication Value Task measures were related to individual variation in pure tone thresholds. We also determined the extent to which the Communication Value Task was related to a widely used measure of delay discounting to validate task measures as indices of discounting. Again, while discounting tasks appear to characterize relatively stable traits48. Specifically, the difference in time and reward for each item of the MCQ (described below) explained less than 60% of the variance in their decisions48. In contrast, the same discounting task parameters explained an average of 95.43% (sd = 0.07) of the variance in item choices for the remaining 44 participants. Table Informed consent was obtainted from forty-seven middle-aged and older adults  who participated in this Medical University of South Carolina (MUSC) Institutional Review Board approved study, which was performed in accordance with the Declaration of Helsinki. Participants were recruited and had their pure tone threshold data collected through ongoing hearing studies at MUSC. Three participants had unreliable delay discounting scores and were excluded50, we created low and high frequency pure tone threshold variables that were averaged across ears. They were created using weights from a factor analysis of 1704 pure tone thresholds . To provide the reader a better understanding of the scaled values of these measures, a low frequency construct value of 0 corresponds to an approximate value of 17 dB HL for the average of 250 Hz and 500 Hz thresholds and a high frequency construct value of 0 corresponds to an approximate value of 41 dB HL for the average of thresholds from 1000 Hz to 8000 Hz.Figure (42) = 0.03, ns) and accounted for 100% of the variance in the average pure tone threshold. Identification of two statistically unique pure tone threshold variables in older adults is consistent with the premise that there can be different mechanisms of age-related hearing loss that differentially affect low versus high frequency thresholds51. Thus, we were able to characterize the extent to which different patterns of hearing loss related to the Communication Value Task measures.The low and high frequency hearing constructs were unrelated  the Communication Value Task; (2) a visual text recognition in noise task to control for individual differences in visual acuity that could affect performance on the Communication Value Task; (3) the MCQ; and (4) the HHIEParticipants viewed sentences that were described as spoken by an administrative assistant or a surgeon during an outpatient clinic visit. The rationale for this design was to manipulate the potential health importance of information using a communication scenario that would be important to most people. The speaker information was presented in different SNR conditions so that we could examine 1) participant demand for information before making a health importance decision and 2) the extent to which this work was dependent on the expected health importance of the information (surgeon vs. administrative assistant). Demand was defined as the frequency of repeated viewing or re-glimpsing briefly presented sentences (875 ms) across SNR conditions.One sentence was presented on each trial (n = 48) in one of two speaker conditions and six SNR conditions . The speaker conditions were presented in 4 blocks of 12 trials, with the 2 administrative assistant condition blocks that were book-ended by the 2 surgeon conditions. Each sentence appeared for 875 ms based on pilot testing to ensure that the sentences could be read and that participants would have to view the sentences multiple times, particularly in the low SNR conditions, to fully understand the text and make a health importance decision. SNR was manipulated by adding visual noise to the sentence text with the Matlab  imnoise function . = 0.76, ns), character count  = 0.03, ns), or Flesch-Kincaid grade reading level  = 1.46, ns). There were no significant sentence differences between SNR conditions for word count  = 1.13, ns), character count  = 1.47, ns), or Flesch-Kincaid grade reading level  = 0.86, ns).The sentences are presented in Supplementary Table Key-press data were recorded during the task that indicated the response choice and latency for each trial. Key-presses represented whether: 1) the sentence included information “Important” to the participant’s health in this imaginary clinical scenario (Y key); 2) the information was “Not Important” to their health (N key); 3) the participant quit the trial (Q key); or 4) they decided to view again or re-glimpse the stimuli (R key). The importance ratings were used to confirm that the perceived importance of the information with the speaker and SNR conditions was successfully manipulated, while re-glimpsing provided an estimate of demand for information or value. We also examined decisions to quit a trial without making an importance decision as evidence of decision-making value.55. Specifically, response latency differences between two responses can indicate bias for the response with the shorter latency, because shorter latencies suggest that individuals needed less evidence before making their decision. Trials with outlier response latencies, defined as 2.5 SD from the mean of each participant’s response latency, were removed from this analysis. This affected an average of 3.16 ± 1.64 trials per participant.Differences in response latencies between “Important” and “Not Important” decisions were examined to determine the extent to which the health importance ratings were affected by response bias, as inA visual text recognition in noise task was administered to control for differences in the ability to read the sentences in noise Fig. . Across 34. Again, the MCQ includes 27 choices between smaller immediate rewards versus larger delayed rewards. The reward (money) and cost (time to reward) are varied to obtain a measure of discounting rate. We calculated the magnitude of delay discounting as the proportion of the delayed reward choices  relative to the total number of trials, as in57, because this quantity is intuitive to understand and nearly perfectly correlated with logistic regression and economic modeling estimates of discounting57. Lower discounting proportion values indicated greater delay discounting. This proportion measure was used to determine the extent to which delay discounting was related to the performance measures from the Communication Value Task.The MCQ is popular measure of delay discounting because of its ease of implementation, strong predictive power, and because real rewards produce similar discounting resultset al., 1990). Standard scoring of the HHIE was performed . Responses to the items were summed to produce a total HHIE score .The 25-item HHIE was used to estimate the self-assessed social/situational (12 questions) and emotional (13 questions) consequences of hearing impairment  on each trial (t). Three separate GLMMs were performed to examine influences on 1) “Important” vs “Not Important” decisions, 2) quitting a trial vs all other response options , and 3) sentence re-glimpsing vs all other response options. SNR and speaker conditions, as well as their interaction, the pure tone threshold constructs, and MCQ delay discounting were included as independent variables. In summary, the logistic regressions can be described as Dt = SNR * Speaker + Low Frequency Threshold Construct + High Frequency Threshold Construct + Delay Discounting + (1|Participant) + error. The effects for each independent variable are described below using Z-scores. Regression and t-test comparisons were used to clarify the relative independence of significant associations and clarify GLMM results. Data were rank-ordered when there was evidence of a non-normal distribution .Logistic regression analyses were performed using generalized linear mixed models  to examine how the experimental conditions, pure tone thresholds, and delay discounting measures influenced decision-making  condition Table . SNR wasThe GLMM analyses also revealed that significant effects of speaker condition were observed for the health importance ratings and decision to re-glimpse the sentences. The significant difference in frequency of “Important” ratings between speakers was largely due to the highest SNR conditions. This result was validated by a significant interaction between speaker condition and SNR Table , which e(43) = 2.78, p = 0.008; SNR 5 “Important” sentences: t(43) = 1.79, p = 0.080) and more frequently re-glimpsed the administrative assistant compared to the surgeon sentences before making a “Not Important” decision (SNR 6 “Not Important” sentences: t(43) = −5.23, p = 0.000005: SNR 5 “Not Important” sentences: t(43) = −4.26, p = 0.0001). There were no significant re-glimpse differences between speaker conditions in the lowest SNRs. Thus, participants appeared to use re-glimpsing in the most intelligible conditions to confirm an expectation about the health importance of the speaker sentences.While the GLMM results indicated that re-glimpsing was most strongly influenced by SNR Table , additioThe GLMM analyses demonstrated that participants with elevated high frequency hearing thresholds more frequently button-pressed to indicate that information from an administrative assistant and surgeon would be “Important” to their health rather than “Not Important” Table , which a“Important” and “Not Important” ratings across trials were not inverse measurements because of the option to quit a trial. There appeared to be greater sensitivity to individual differences for the “Not Important” decision when aggregating data across trials. For example, Table 55, we examined the average response latency for “Important” and “Not Important” decisions. As shown in Fig. (39) = −0.35, p = 0.023]. Hierarchical multiple regression showed that the high frequency hearing construct was no longer predictive of the response latency estimate of response bias when the proportion of “Not Important” ratings was included in the model  = −0.35, p = 0.019; administrative assistant: r(42) = −0.30, p = 0.046). Table Participants with higher delay discounting, or cases who would prefer a smaller immediate reward compared to a larger delayed reward, re-glimpsed each sentence fewer times than participants with lower delay discounting Tables ; Fig. 5.2 = −0.35Finally, delay discounting was not significantly associated with the pure tone threshold measures Table , but didThe Communication Value Task was designed to measure the demand for information to make a decision about health care listening scenarios across different speaker and SNR conditions. Our goal was to measure a trait that influences performance across different types of tasks and that could be used to provide an objective measure of effort in people with hearing loss. In support of this goal, delay discounting significantly predicted how hard participants worked to read and make a health importance decision about sentences in noise. Participants with elevated pure tone thresholds in the high frequencies more frequently reported that information would have health importance. However, people with hearing loss did not exhibit evidence of working harder to make a health importance decision. This dissociation highlights the significance of obtaining behavioral measures of expected value because self-report may not always be indicative of value when there is potential for subjective bias. These results suggest that the Communication Value Task measures different dimensions of decision-making that have relevance to understanding hearing health behaviors.16 and the absence of performance-based discounting tasks for hearing studies provided the motivation for developing a measure to predict hearing health behaviors, such as the frequency of hearing aid use. In developing this task, we considered evidence that speech recognition in noise engages neural systems that estimate the expected value from optimizing task performance with increasing task difficulty58 or lower SNR1. For these reasons, we wanted a measure of expected value from communication and chose to define value as the demand for information to make a health importance decision across SNR conditions. Specifically, the demand or re-glimpsing measure is conceptually similar to asking speakers to repeat what they said in difficult listening conditions. The likelihood that someone interrupts a speaker to repeat can depend on the expected value of the information conveyed, particularly among older adults with hearing loss36.Evidence that expected value can affect hearing-aid use and outcomes59.Manipulating the visual SNR did require participants to work harder in the low SNR conditions to make a decision. Moreover, re-glimpsing was higher in cases with lower MCQ delay discounting. In other words, the cost/benefit decision-making that is characterized by the MCQ predicted how hard people would work to make an informed decision. To the extent that our measure of demand reflects effort discounting, this association with the MCQ appears to be consistent with modest associations between delay and effort discountingThe results of the current study may explain why delay and effort discounting measures can exhibit modest associations. Re-glimpsing increased the length of time that participants spent on each trial, which lengthened duration of the task. Thus, effort discounting tasks where effort increases the duration of the task would be expected to exhibit stronger associations with measures of delay discounting.60, perhaps because they are investing more time to recognize speech. Future studies will examine how variation in these behavioral economic measures predict hearing aid ownership, frequency/duration of use, and satisfaction.Importantly, age, sex, or hearing loss were not significantly associated with re-glimpsing or delay discounting. These results indicate that the demand for information that is measured with the Communication Value Task can vary across older adults, including older adults with elevated pure tone thresholds. There was a modest relation between self-reported hearing-handicap and delay discounting, which was significant after accounting for hearing thresholds. This observation may be consistent with evidence that older adults with high hearing-handicap also report increased speech recognition effort and frustration61. For example, response caution was observed when participants were asked to detect an auditory stimulus that occured without a cue compared to when the timing of presentation was cued62. In the current study, response bias depended on the speaker condition and SNR condition. For example, the decision that surgeon sentences would be not important to one’s health appeared to involve more caution because of the understanding that the hypothetical listening scenario involved a health care setting.The Communication Value Task was sensitive to response bias, particularly for the administrative assistant sentences with decreasing SNR. There is evidence that response bias increases with increasing stimulus uncertainty in perceptual decision-making tasks, where the direction of the bias is determined by cues and/or priors that provide information about the likelihood of an event63. Older adults also were more likely to report hearing a word rather than a non-word compared to younger adults64. The authors suggested that bias for word judgements provided a performance strategy benefit because it occurred with a tendency to recognize words more quickly. A similar strategy could explain why the bias results are in the opposite direction of a larger literature suggesting that older adults exhibit increased response caution based on response latency data65.Response biases during perceptual decision-making tasks have been observed to change with age in studies of older adults. For example, older adults exhibited a positive bias in reporting that they had recognized words in noise compared to younger adults during a word recognition in noise task66. The speed – accuracy tradeoff for a given task may determine the response bias that older adults demonstrate. In the current study, there was response latency evidence that older adults with elevated high frequency hearing thresholds took less time to make “Important” decisions and took more time to make “Not Important” decisions. Response latency differences between conditions can result from response preferences67, which make non-preferred responses relatively more effortful and slower55. Together with the findings described above, this pattern of response bias guides the interpretation that participants with high frequency hearing loss were biased to make a judgement that met an expectation based on the health care context of the experiment.In many experiments, older adults slow their behavior to optimize performance69 that increase the perceived importance of information in a health care setting. In this context, the bias towards deciding that health information is important could reflect a management or balancing of choices to minimize error and improve decision-making70. Here, older adults with high frequency hearing loss and co-morbid health problems may have better health care outcomes if they are biased to consider more information in a clinical setting as important to their health. While a limitation of this study is the absence of data about co-morbid health conditions, the hearing loss and bias results were independent of age differences and age would be expected to covary with comorbid health conditions.But why does response bias increase with age-related high frequency hearing loss? This response bias effect did not appear to be due to a co-morbid visual impairment as the measure of text recognition in noise did not predict response latency differences between health importance choices. Older adults with hearing loss may rate the sentences as having health importance because of other comorbid health conditions and related health care visits and expensesOne additional explanation for the hearing loss and bias finding, which is based on the response bias literature described above, is that the daily experience of hearing difficulty increases a dependence on a response bias strategy across different types of perceptual tasks. This bias could stem from the expectation that working harder does not always provide benefit when information is too difficult to perceive and thus serves as strategy to conserve energy. While somewhat speculative, this interpretation is supported by evidence that the high frequency hearing threshold and importance rating was strongest in the less intelligible SNR conditions. Future study of co-morbid health conditions and health care experiences is necessary to resolve the question as to why high frequency hearing loss was associated with increased response bias.Finally, we also interpreted the hearing loss and elevated frequency of “Important” decisions or decreased frequency of “Not Important” decisions to reflect response bias because this association occurred in the absence of increased re-glimpsing to make an informed decision, particularly when the stimuli were difficult to perceive. These results indicate that the expected importance of information may not always align with how hard people are willing to work when stimuli are difficult to perceive.We developed a performance-based measure of communication value that assesses the demand for information or how hard people are willing to work to make health importance decisions. There were two primary results of interest. First, the task appears to characterize a behavioral economic discounting construct based on the frequency with which people re-glimpse the briefly presented stimuli. Second, the task appears to characterize response bias that was most pronounced in people with high frequency hearing loss. While these results were independent of variation in text recognition in noise for this visual task, studies involving auditory stimuli are necessary to determine the specificity of the results and further establish the applicability of the Communication Value Task to understanding hearing health behaviors.Supplemental Table 1


Combined effect of cigarette smoking and occupational noise exposure on hearing loss has rarely been evaluated among Chinese population, especially among females. This cross-sectional study was conducted in 11196 participants of Dongfeng-Tongji cohort study. Smoking status was self-reported through questionnaire and occupational noise exposure was evaluated through workplace noise level and/or the job titles. Hearing loss was defined as a pure-tone mean of 25 dB or higher at 0.5, 1, 2, and 4 kHz in both ears. Compared with participants without occupational noise exposure, the risk of hearing loss was significantly higher for noise exposure duration ≥20 . The association was particularly evident among individuals who were males  and aged ≥ 70 . Similarly, the risks increased with the increasing of pack-years in males and all age groups except for those aged <60. As to the combined effect, the hearing loss risk was highest for noise exposure duration ≥20 and pack-years ≥25 , especially among males  and those aged ≥70 . Smoking may be an independent risk factor for hearing loss. And it may synergistically affect hearing when combined with occupational noise exposure, especially among males and older participants. It is estimated that approximately 600 million workers worldwide and 30 million American workers are exposed to occupational noise3. In Europe, it is reported that almost 28% of workers work in occupational settings with noise levels between 85 and 90 A-weighted decibels (dBA)4. And it may be more serious in China owing to its larger occupational population5.Occupational noise is considered one of the most pervasive occupational hazards around the world7, and occupational noise exposure has also been associated with sleeping disorders8, ECG abnormalities9 or hypertension10. Persistent damage on hair cells and hearing conduction nerves induced by long-term exposure to relative high level of occupational noise was thought to be a key reason for hearing loss11. Noise induced hearing loss (NIHL) is the change in the hearing threshold at different frequencies, it is chronic and characterized as sensorineural, usually symmetrical and bilateral12. NIHL could bring a lot of inconvenience to people in later life and cause a large social and economic burden, and hearing loss due to occupational noise has been described as a primary condition of modern society13. Published papers reported that an estimation of 278 million people were hearing disabilities in the world14, and the economic costs have been estimated to be about billions of dollars15. Although NIHL is permanent and irreversible, it is still preventable 16.Adverse health effects with exposure to occupational noise are of increasing health concern. Hearing loss is a well-known consequence of long-term exposure to high level noise18. Besides, cigarette smoking could also lead to elevated susceptibility to noise damage, as well as causing its own damage on hearing system19. Cigarette smoking is a common habit in the world, according to the World Health Organization, China has about 320 million smokers which represent one third of the world’s total smokers20. As a modifiable lifestyle, the association between cigarette smoking and hearing loss has been paid more attention in recent years. However, the results of the published reports were inconsistent.Except for occupational noise mentioned above, several other risk factors are also reported to be associated with hearing loss, such as age, sex, race, ototoxic medication, hypertension, and diabetes mellitus23, but others do not support a uniform relationship25. The association between smoking and hearing loss has rarely been evaluated among female participants and evidence is limited in China. Moreover, the combined effect involving smoking and occupational noise exposure on hearing loss is noticeable due to the high prevalence of smoking among occupational workers in China26. Therefore, we conducted a cross-sectional study to examine the independent and combined effects of smoking and occupational noise exposure on hearing loss in a large middle-aged and older Chinese population, especially to explore the association among female participants.Several epidemiology studies have found a positive association between smoking and hearing lossCharacteristics of the 11196 participants included in the analysis were reported by categories of hearing loss . Besides, it also revealed that smoking may be an independent risk factor for hearing loss and it may have a dose-response relationship on hearing loss, which was consistent with part of previous studies29. The divergent outcome may be due to the different definitions and criteria of NIHL among studies. Though the mechanism by which cigarette smoking increased the risk of hearing loss was not clear, it was indicated that smoking may damage hair cells by increasing carboxyhaemogolobin or by reducing blood flow to cochlea31.In the present study of middle-aged and older adults in Chinese retired workers, occupational noise exposure and cigarette smoking, independently or in combination, were found to be associated with increased risk of hearing loss. High risks of hearing loss were observed among participants long-term exposed to occupational noise and/or took more pack-years of smoking, even controlling for other confounders. Long-term exposed to occupational noise could damage hair cells of the organ of Corti directly, resulting in irreversible and progressive hearing losset al. in Iran found smoking could accelerate noise induced hearing loss32, Ferrite and Santana in Brazil found smoking may synergistically affect hearing when in combination with noise exposure33. Mizoue et al. in Japan also found smoking was a risk factor for high frequency hearing loss and had a positive combined association with occupational noise exposure19. However, these studies were conducted among male workers, not including female workers. The results of our study showed the prevalence of hearing loss in females was lower than that in male participants. However, increased risks of hearing loss were also observed among female participants with cigarette smoking and long term exposure to occupational noise. It was concluded that low percent of smoking  or exposure to occupational noise  may contribute to the phenomenon in females.Our study showed the combined effect of smoking and occupational noise exposure was greater than their independent effects. Individuals with longest noise exposure duration and maximum pack-years got the highest risk in the present study, which was reported in other studies. Pouryaghoub In the present study, we also explored the independent and combined associations in the subgroup of sex and age. During the independent association, we did not found significant associations between maximum pack-years of smoking (≥25 pack-years) and hearing loss among females and the youngest age group (<60). Meanwhile, the combined associations were not found in aforementioned two groups either. However, these associations could also be found in other female (0 ~ <25 pack-years) and age groups (60 ~ <70 and ≥70). It may mainly be due to the small number of participants in these categories (ranging from 4 to 58), which resulting a limited statistical power. Thus the independent and combined associations among females and the youngest age group (<60) needed to be confirmed further in future studies with larger sample size.17. However, the sample size of the present study was large, which could reduce possible bias. Thirdly, the results of our study were limited to middle-aged and older adults, thus it may not be generalized to populations of all ages.Some limitations in the present study should also be acknowledged. First, our study was a cross-sectional design, which would restrict the evidence of causal inferences. Second, although a number of confounders were adjusted in our study, there were still some other factors which were not included, such as leisure time noise exposure, which was also reported to be associated with hearing lossIn summary, the present study reveals that smoking is an independent risk factor for hearing loss. And it may synergistically affect hearing when in combination with occupational noise exposure, especially among males and older participants. The associations among females and the youngest age group need to be confirmed in future studies with larger sample size.34. Briefly, all the participants were retired employees from Dongfeng Motor Corporation (DMC), each participant has a unique medical insurance card number in the DMC’s health-care service system. The cohort study was established in 2008 and was followed up for every five years. Finally, a total of 27,009 retired employees completed baseline questionnaires and medical examinations. And five years later, 25,978 individuals (96.2%) completed the follow-up until October 2013. In 2013, 11513 participants from the baseline underwent the audiometric examination. Further excluded from this group were individuals without auditory examination results (n = 57), those who provided incomplete baseline information (n = 100), leaving 11196 subjects for the present analysis.The study is embedded in Dongfeng-Tongji Cohort Study, a population based cohort study aimed at assessing the relationship of dietary, lifestyle, occupational and environmental factors and the development of chronic diseases, which has been reported elsewhere35, it was defined as a pure-tone mean of 25 dB or higher at 0.5, 1, 2, and 4 kHz in both ears37.Each subject was given a general physical and an otologic examination first. Then pure-tone audiometry was performed in a sound-isolated room with a calibrated pure-tone audiometer (Micro-CD21) by certified audiologists. Air conduction thresholds were determined for each ear at 0.5, 1, 2, 4 and 8 kHz across an intensity range of −10 to 120 dB. The non-responses were coded as missing values. As occupational hearing loss was usually supposed to bilateral and fairly symmetrical29. Besides, years of occupational noise exposure was divided into four groups: 0, 1 ~ <10, 10 ~ <20, ≥20.The occupational information of each subject was self-reported and obtained from questionnaire, which contained personal data on employment and variables about the work, such as the corporation, the job title and the duration of each job. The occupational noise level for each job title at workplace came from the company records which were measured by qualified institutions. Noise exposure levels for workplaces outside of DMC were determined through the job description, and were consulted with local occupational hygienists. The occupational noise exposure was defined as exposed to a time-weighted-average (TWA) noise level of 80 dB (A) for at least a year21.Smoking status was self-reported and it was divided into three groups: current smokers, ex-smokers and nonsmokers. Individuals smoking at least one cigarette per day for more than half a year were defined as current smokers. Nonsmokers were defined as those who seldom or had never smoked in their lifetime. And ex-smokers were those who ever smoke and do not smoke at present. The number of cigarettes smoked or ever smoked per day and the duration of smoking was also recorded for current smokers and ex-smokers. Meanwhile, total pack-years were defined as the number of cigarettes smoked per day divided by 20 per pack, and then multiplied by years of smokingThe study was approved by the Ethics and Human Subject committee of Tongji Medical College, and Dongfeng General Hospital, DMC. The methods were carried out in accordance with the relevant guidelines and regulations. The written informed consents were obtained from all the participants.17, it was classified into three groups: <60, 60 ~ <70, ≥70. Individuals who drink at least one time per week for more than half a year were defined as current drinkers. And non-drinkers were defined as those who seldom or had never drank in their lifetime. Hypertension was defined as blood pressure ≥140/90 mmHg or self-reported physician diagnosis of hypertension or self-reported current use of antihypertensive medication. Use of ototoxic medication was counted when participants reported medications of loop diuretics, aminoglycoside or non-steroidal anti-inflammatory drugs. Chronic diseases history diagnosed by a physician was reported by the participants, including diabetes mellitus, coronary heart disease, myocardial infarction, and stroke.Information on sociodemographic characteristics , shift work, drinking status, hypertension, ototoxicity medicine, and chronic diseases history were collected through a questionnaire by face to face interview with trained interviewers. As hearing loss varied by age38. The models were conducted with those do not smoke and no occupational noise exposure as the reference group. We chose covariates which could affect hearing loss according to evidence from published literatures21. Covariates included age, sex, race, shift work, drinking status, hypertension, ototoxicity medicine, and chronic diseases history . All statistical analyses were performed using SAS version 9.2 software . The statistical tests were two sided, and significance was set at P < 0.05.Sociodemographic characteristic of participants was reported as mean (SD) for continuous variables and as number (percentages) for categorical variables. Logistic regressions were performed to evaluate the independent and combined associations of occupational noise exposure and smoking with hearing loss. Then the associations were further evaluated with stratified sex and age, based on previous published reports suggesting that age and sex may be important factors for hearing lossThe datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.Table S1, Table S2


We found hard magnetic grains were surrounded by thin and continuous layers along the grain boundaries (GBs) with a high concentration of ferromagnetic elements (Fe + Co >74 at%). The obvious positive peak in the δM plot and the interaction domain structure observed by Lorentz magnetic microscopy indicate that there is strong exchange coupling interaction through the ferromagnetic GB phase between hard magnetic grains. The annealing in an applied magnetic field of 1 T increases the remanence by enhancing the exchange coupling interaction, leading to a maximum product energy ((BH)max) which is 16% higher than that of melt-spun ribbons. We also studied the temperature dependence of the coercivity in a temperature range of 300–500 K, and proposed that the coercivity of melt-spun (Nd0.8Ce0.2)2.4Fe12Co2B ribbons with ferromagnetic GB phase at room temperature was from the combination of strong domain-wall pinning and nucleation. The same mechanism works in the annealed ribbons.Understanding the coercivity mechanism has had a substantial impact on developing economically more attractive RE-based (RE = rare earth) permanent materials because of price volatility of key RE metals  in recent years. In this work, we investigated the microstructure and magnetic properties of melt-spun (Nd The powders pulverized from melt-spun Nd-Fe-B ribbons are currently used as raw materials for the production of bonded magnets and hot-pressed magnets [2Fe14B alloy deteriorates the hard magnetic properties because the magnetic properties of Ce2Fe14B are inferior to those of Nd2Fe14B [−1) and (BH)max (100 kJ∙m−3) for melt-spun (Nd0.8Ce0.2)2.4Fe12Co2B ribbons by simultaneous substitution of Nd by Ce, and Fe by Co [Ndoperties . Melt-sp magnets ,6. The e magnets ,8,9. How2Fe14B based alloys, the GB phase has a strong influence on the coercivity. For example, the coercivity is enhanced by isolating Nd2Fe14B grains with non-ferromagnetic Nd-rich phase at the GBs [2Fe14B grains and reduces the coercivity [2Fe14B based alloys with GB phase needs to be further investigated. Remanence is another extrinsic magnetic property and can be improved by grain size refinement or an enhancement of the exchange coupling interaction using magnetic field annealing heat-treatment [0.8Ce0.2)2.4Fe12Co2B ribbons as well as samples annealed in a 1 T magnetic field to obtain a deeper insight into the coercivity mechanism. Moreover, we used magnetic field annealing treatment to modify the chemical composition of the GB phase to achieve a relatively high level of coercivity and remanence, and obtained high performance permanent materials. We found that the GB phase had high concentration of ferromagnetic elements (Fe + Co > 74 at%) in melt-spun ribbons and annealed samples at 773 K for 15 min with 1 T magnetic field. The remanence of annealed samples was enhanced due to strengthened exchange coupling interaction through the ferromagnetic GB phase, leading to 16% higher (BH)max than that of melt-spun ribbons. Moreover, we proposed the coercivity in melt-spun (Nd0.8Ce0.2)2.4Fe12Co2B ribbons with ferromagnetic GB phase at room temperature was from the combination of strong domain-wall pinning and nucleation.Coercivity is an extrinsic magnetic property and it is intimately related to the microstructure of a magnetic material. In Nd the GBs ,12,13,14ercivity ,17,18,19reatment ,21,22. I0.8Ce0.2)2.4Fe12Co2B were prepared by arc-melting the mixture of pure metals Nd (99.99%), Fe (99.99%), Co (99.99%), Ce (99.99%), and Fe-B alloy in an argon atmosphere. Ingots were re-melted four times for homogenization. Ribbons were obtained by melt-spinning in the argon atmosphere at a wheel speed of 15 m∙s−1. During melt-spinning, the distance between an orifice of a quartz crucible and the copper wheel surface was maintained at 8 mm. The quenching temperature and chamber pressure were maintained at 1588 K ± 5 K and 0.05 MPa. The heat-treatments were carried out for melt-spun ribbons in the range of 573–1023 K for 15 min using a vacuum furnace with 1 T magnetic field. The direction of the magnetic field was parallel to the longitudinal ribbon plane. The density of the (Nd0.8Ce0.2)2.4Fe12Co2B alloy was 7.71 g∙cm−3 using Archimedes principle. The exchange interaction curve (δM-H curve) was determined from the measurement of isothermal remanence magnetization (IRM) and DC demagnetization (DCD) curve. The sample for the IRM curve was virgin state. The detailed measurement of the IRM and DCD curve was introduced in reference [α radiation. The high angle annular dark field (HAADF) image and elemental characterization were performed by a scanning transmission electron microscope with energy-dispersive X-ray spectroscopy (STEM-EDS) . Cross-section samples near the wheel surface  and free surface of ribbons for TEM and atom probe tomography (APT) observations were made by a Helios 600i focus ion beam (FIB) . The APT characterizations were carried out in a CAMECA Instruments LEAP4000X-HR local electrode atom probe . Data acquisition was performed at a specimen tip at 50 K with a target evaporation rate of 0.5%, and a pulse-to-standing DC voltage ratio of 20%. Atom probe data reconstruction was conducted using the CAMECA Integrated Visualization and Analysis Software (IVASTM 3.6.8).Ingots with stoichiometric composition (Nd0.8Ce0.2)2.4Fe12Co2B ribbons were annealed from 573 K to 1023 K for 15 min with 1 T magnetic field, see ciH) decreases from 1285 kA∙m−1 for the melt-spun sample to 1189 kA∙m−1 for the annealed sample, whereas the remanence (rB) increases from 0.76 T to 0.82 T. As a consequence, a max(BH) with a rise of 16% (from 96 kJ∙m−3 to 111 kJ∙m−3) is obtained for the annealed sample. The key magnetic parameters are listed in The melt-spun (NdciH as a function of temperature (T) is given byH0 is the critical field in the absence of thermal activation, Bk is Boltzmann constant, 4b is the interaction range of a pin equating with the domain wall width, wδ, and f is the maximum restoring force per pin.For the case of strong pinning of domain walls developed by Gaunt , Hci as ciH)1/2 and T2/3 in K and effN are microstructural parameters and are related to the non-ideal microstructure of a real magnet. The parameter Kα describes a reduction of the nucleation field due to an inhomogeneous microstructure. effN is an average effective local demagnetization factor. The minimum nucleation field, 0HNminµ(T), represents a value for the nucleation field of the misaligned grains.The linear relationship between (Equation (2) can be rewritten as0Hcµ(T)s/M(T) versus 0HNminµ(T)s/M(T) should yield a straight line with slope Kα and intersection effN. 0.8Ce0.2)2.4Fe12Co2B alloy. The fitting parameters by a standard linear least-squares method to Equation (3), Kα and effN are shown in Kα is 0.67 and 0.66, and effN is 0.58 and 0.61 for the melt-spun sample and annealed sample, respectively. The value of Kα is almost the same for both samples. The data in 0.8Ce0.2)2.4Fe12Co2B ribbons at room temperature. Moreover, the same mechanism works in the annealed samples.According to Equation (3), a plot of 0.8Ce0.2)2.4Fe12Co2B ribbons and annealed samples at 773 K for 15 min with 1 T magnetic field are shown in 214B phase (2:14:1 phase) is observed in both samples, indicating that magnetic field annealing treatment does not change the phase constitution. Our previous work [0.8Ce0.2)2.4Fe12Co2B ribbons prepared at a wheel speed of 15 m∙s−1 and a chamber pressure of 0.05 MPa. The grain size distribution is determined from the TEM images, as shown in 0.8Ce0.2)2.4Fe12Co2B alloy has a homogeneous microstructure through the thickness of the ribbon. Hence, the free surface of the ribbons was chosen to further investigate the microstructure and chemical composition of the grain boundary phase.XRD patterns of the wheel surface and free surface of melt-spun (Ndous work  found ho0.8Ce0.2)2.4Fe12Co2B alloy is ferromagnetic, which leads to an exchange coupling interaction between the hard magnetic 2:14:1 grains. An effective method of understanding the exchange coupling interaction is via the so-called δM plot. Based on Wohlfarth’s theory; Kelly et al. [H is an applied magnetic field, d (H)M is the reduced magnetization, and r(H)M is the reduced remanence magnetization. The values of d(H)M and r(H)M were obtained from the measurement of the IRM and DCD curves. It is worth noting that the sample for the IRM curve was virgin state. Hence, the IRM curve of the annealed sample with 1 T magnetic field could not be measured due to its magnetized state. δM plot of the melt-spun sample. The curve is initially positive, indicating the existence of exchange coupling interaction dominating the magnetization. Then the curve drops to negative values, suggesting that magnetostatic interaction is dominant. The obvious positive δM peak in 2Fe14B [In 2012, Sepehri-Amin et al., reported that a thin GB phase with high concentration of Fe + Co (~65 at%) was observed in sintered NdFeB magnets by three-dimensional atom probe, and suggested that this thin GB phase was ferromagnetic . Furthery et al.  definedn 2Fe14B ). It is n 2Fe14B . It indiirrχ) curve. irrχ curves for the melt-spun and annealed samples. A single sharp peak is observed in both samples, which is typical of a single-phase magnet [irrχ curves indicates that each grain couples well with its neighboring grains due to exchange coupling between the magnetic phases. The annealed sample shows a narrower peak than the melt-spun sample, suggesting a stronger exchange coupling interaction through the ferromagnetic GB phase. As a consequence, the remanence is enhanced by about 8% from 0.76 T to 0.82 T.In the annealed sample with 1 T field, the GB phase with high concentration of ferromagnetic elements (Fe + Co = 80 ± 1 at%) enhances the exchange coupling and can be demonstrated through the irreversible susceptibility (e magnet . The nar0.8Ce0.2)2.4Fe12Co2B ribbons with the ferromagnetic GB phase at room temperature is from the combination effects of pinning of domain walls and nucleation. The microstructural investigations show that the 2:14:1 grains are surrounded by thin layers at the GBs, which can provide more pinning sites for domain wall motion. That is, the regions at the GBs are responsible for domain wall pinning because the presence of the ferromagnetic GB phase with lower magnetocrystalline anisotropy may give rise to a pinning force for magnetic domain wall motion. The plot of 0Hc(T)/Ms(T)μ versus 0HNmin(T)/Ms(T)μ for melt-spun (Nd0.8Ce0.2)2.4Fe12Co2B ribbons in kα = 0.67 and effN = 0.58 of melt-spun (Nd0.8Ce0.2)2.4Fe12Co2B ribbons do differ markedly from 0.25 and 0.26 observed in the melt-spun Nd-Fe-B ribbons [Kα and small value of effN are helpful for the enhancement of the coercive field in the NdFeB materials [Kα is 0.67 and 0.66, and is almost the same for the melt-spun sample and the annealed sample. The value of effN is 0.58 for the melt-spun sample, which is smaller than 0.61 for the annealed sample. That is, the melt-spun sample has a larger value of the coercivity, see BH)max (111 kJ∙m−3) in this work for (Nd0.8Ce0.2)2.4Fe12Co2B ribbons annealed with 1 T magnetic field is 11% higher than 100 kJ∙m−3 of the same alloy prepared by melt-spinning and subsequent annealing without magnetic field [BH)max (111 kJ∙m−3) at room temperature is also 23% higher compared to 5.9 wt% Dy containing Nd-Fe-B ribbons [In melt-spun Nd-Fe-B ribbons, the pinning of magnetic domain walls is believed to be a dominant coercivity mechanism . In our  ribbons . The laraterials . In Tabl ribbons .0.8Ce0.2)2.4Fe12Co2B ribbons and annealed samples at 773 K for 15 min with 1 T magnetic field. The exchange couple interaction through the ferromagnetic GB phase was confirmed by the δM-H curve and Lorentz microscopy. Magnetic field annealing increases the segregation of Co leading to a concentration of (Fe + Co) with 80 ± 1 at% at the GBs, which results in a stronger exchange coupling interaction between the 2:14:1 grains. Hence, compared to the melt-spun sample, the (BH)max was improved by 16% after annealing with a 1 T field. We propose that the coercivity of the melt-spun (Nd0.8Ce0.2)2.4Fe12Co2B ribbon with ferromagnetic GB phase at room temperature is from the combined effects of the pinning of the domain walls and nucleation. Magnetic field annealing treatment does not change the coercivity mechanism. Our findings give further insight into the coercivity mechanism of melt-spun Nd-Fe-B ribbons with GB phase and provide a new idea to design low-cost and prospective permanent alloys with ferromagnetic GB phase.In summary, we investigated the relationship between the microstructure and magnetic properties of melt-spun (Nd