Rapid Crystallization and Fluorescence of Poly(ethylene terephthalate) Using Graphene Quantum Dots as Nucleating Agents.

In this study, graphene quantum dots (GQDs) with a diameter of ~3 nm were successfully synthesized and incorporated into a poly(ethylene terephthalate) (PET) matrix to fabricate PET/GQDs nanocomposites. The impact of GQDs on the crystallization and thermal stability of the PET/GQDs nanocomposites was investigated. It was observed that the addition of only 0.5 wt% GQDs into the nanocomposites resulted in a significant increase in the crystallization temperature (peak temperature) of PET, from 194.3 °C to 206.0 °C during the cooling scan process. This suggested that an optimal concentration of GQDs could function as a nucleating agent and effectively enhance the crystallization temperature of PET. The isothermal crystallization method was employed to analyze the crystallization kinetics of the PET/GQDs nanocomposites, and the data showed that 0.5 wt% GQDs significantly accelerated the crystallization rate. Furthermore, the incorporation of GQDs into the PET matrix imparted photoluminescent properties to the resulting PET/GQDs nanocomposites. The PET crystals with GQDs as crystal nuclei and the crazes caused by defects played a vital role in isolating and suppressing the concentration quenching of GQDs. This effect facilitated the detection of defects in PET.

Epoxy-Modified Bismaleimide Structural Adhesive Film Toughened Synergistically with PEK-C and Core-Shell Polymers for Bonding CFRP.

Bismaleimide (BMI) resin-based structural adhesives have excellent heat resistance, with important applications demonstrated in the bonding of high-temperature BMI composites. In this paper, we report an epoxy-modified BMI structural adhesive with excellent properties for bonding BMI-based CFRP. We prepared the BMI adhesive using epoxy-modified BMI as the matrix and PEK-C and core-shell polymers as synergistic tougheners. We found that the epoxy resins improve the process and bonding properties of BMI resin but slightly reduce thermal stability. PEK-C and core-shell polymers synergistically improve the toughness and bonding performances of the modified BMI adhesive system and allow the maintenance of heat resistance. The optimized BMI adhesive exhibits excellent heat resistance, with a high glass transition temperature of 208.6 °C and a high thermal degradation temperature of 425.4 °C. Most importantly, the optimized BMI adhesive exhibits satisfactory intrinsic bonding and thermal stability. It has a high shear strength of 32.0 MPa at room temperature and up to 17.9 MPa at 200 °C. The BMI adhesive-bonded composite joint has a high shear strength of 38.6 and 17.3 MPa at room temperature and 200 °C, respectively, indicating effective bonding and excellent heat resistance.

Vitrimeric silicone composite with high thermal conductivity and high repairing efficiency as thermal interface materials.

Thermally conductive composites with self-healing ability can not only solve the heat dissipation problem of integrated electronic devices but also help improve their service life, thereby reducing electronic waste. In this study, a self-repairing thermally conductive composite with good electrical insulation, high thermal conductivity, high healing efficiency, and excellent mechanical strength was designed and prepared using a silicon vitrimer as the matrix and functionalized boron nitride nanosheets (fBNNS) as the thermally conductive filler. The tensile strength of the vitrimers with 10 wt% of octaglycidyl polyhedral oligomeric silsesquioxane (POSS) increased by 2.82 times to 8.4 ± 0.1 MPa with respect to that without POSS. In addition, the composites exhibited excellent thermal conductivity of 1.41 ± 0.05 W/mK with 66 wt% of fBNNS, which is more than 6 times higher than that of undoped elastomers. More importantly, the repair efficiency of undoped vitrimeric silicone can be as high as 98.8 ± 1.1%, which was slightly reduced to over 92.0% by adding 66 wt% of fBNNS. Further, it could recover 99.3% of the thermal conductivity even after 6 healing cycles. The self-healing thermally conductive composites exhibited excellent wettability and good adhesion to different wafers and substrates, demonstrating excellent performance as thermal interface materials for high-power electronic devices.

Surface Treatment of Composites with Bismaleimide Resin-Based Wet Peel Ply for Enhanced Adhesive Bonding Performance.

Surface treatment is typically required to improve the bonding performance of carbon-fiber-reinforced composites. Herein, a wet peel ply was prepared using bismaleimide (BMI) resins as a matrix resin. The temperature-heating rate extrapolation method and rheological method were employed to study the reaction characteristics and viscosity-temperature characteristics of the matrix in the BMI wet peel ply. The curing temperatures of the BMI wet peel ply and the BMI prepreg were the same (200 °C), making this wet peel ply suitable for co-curing with the BMI prepreg. After treatment with the wet peel ply, the bonding strength of the BMI composite joint showed a mean shear strength of 35.5 MPa, which was 1.72% higher than that of the sanded composite and 17.5% higher than that of the composite treated with the dry peel ply. In addition, the BMI composite treated with the BMI wet peel ply exhibited good bonding stability with a coefficient of variation of 3.9. After damp-heat aging for 1440 h, the retention rate of shear strength at room-temperature was 82.3%. The relatively loosely woven carrier in the BMI wet peel ply increased the surface roughness of the composite, thus improving the bonding strength.

3D Printing of Lightweight Polyimide Honeycombs with the High Specific Strength and Temperature Resistance.

Lightweight structures are often used for applications requiring higher strength-to-weight ratios and lower densities, such as in aircraft, vehicles, and various engine components. Three-dimensional (3D) printing technology has been widely used for lightweight polymer structures because of the superior flexibility, personalized design, and ease of operation offered by it. However, synthesis of lightweight polymeric structures that possess both high specific strength and glass transfer temperature (Tg) remains an elusive goal, because 3D printed polymers with these properties are still very few in the market. For example, 3,3',4,4'-biphenyl tetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA)-type (UPILEX-S type) polyimides show exceptional thermal stability (Tg up to ≈400 °C) and mechanical properties (tensile strength exceeding 500 MPa) and are the first choice if extremely high temperatures of 400 °C or even higher (depending on the duration) are required, which hampers their processing using existing 3D printing techniques. However, their processing using existing 3D printing techniques is hampered due to their thermal resistance. Herein, a 3D printing approach was demonstrated for generating complex lightweight BPDA-PDA polyimide geometries with unprecedented specific strength and thermal resistance. The simple aqueous polymerization reaction of BPDA with water-soluble PDA and triethylamine (TEA) afforded the poly(amic acid) ammonium salt (PAAS) hydrogels. These PAAS solutions showed clear shear thinning and thermo-reversibility, along with high G' gel-state moduli, which ensured self-supporting features and shape fidelity in the gel state. Postprinting thermal treatment transformed the PAAS precursor to BPDA-PDA polyimide (UPILEX-S type). The resulting layer-by-layer deposition onto lightweight polyimide honeycombs in the form of triangular, square, and hexagonal structures showed tailorable mechanical strength, exceptional compressive strength-to-weight ratio (highest up to 0.127 MPa (kg m-3)-1), and remarkable thermoresistance (Tg approximately 380 °C). These high-performance 3D printed polyimide honeycombs and unique synthetic techniques with general structures are potentially useful in fields ranging from automotive to aerospace technologies.

FeII 4L4 Tetrahedron-Assisted Three-Way Junction Probe for Multiple miRNA Detection.

MicroRNAs (miRNAs) modulate a variety of cellular signaling pathways and play a vital role in cell-to-cell communication. The overlapped expression of a certain miRNA is commonly reported to be related to cancers. Therefore, combined detection of multiple miRNAs is of great significance for cancer diagnosis. Herein, we developed a FeII 4L4 tetrahedron-assisted three-way junction (3WJ) probe, which exhibited a higher stability than the normal 3WJ probe, for multiple miRNA detection. In this method, the simultaneous existence of miRNA-21 and miRNA-144 triggers the release of the Y3 sequence in the FeII 4L4 tetrahedron-assisted 3WJ probe, which in turn triggers subsequent CRISPR-Cas12a-assisted rolling circle amplification. Based on this, simultaneous detection of miRNA-21 and miRNA-144 was achieved. Furthermore, we also applied this method to the detection of miRNAs in clinical samples and achieved good agreement with quantitative real-time polymerase chain reaction (qRT-PCR), indicating its significant potentials in early diagnosis and treatment of cancer.

Vitamin D supplementation for improving children with bone mineral density: A protocol for systematic review and meta-analysis.

BACKGROUND: Osteoporosis is usually one of the less perceived complications of chronic illness among children. Previous studies have shown that vitamin D supplementation may be valuable to bone density, especially among children with a deficiency of vitamin D. Yet, the results often remain inconsistent. Therefore, the present study investigates the clinical therapeutic effects of vitamin D supplementation to enhance children with bone mineral density. METHODS: We will search the randomised controlled experiment literature of vitamin D supplementation for bone mineral density, focusing on children, in 3 distinct English databases (EMBASE, MEDLINE via PubMed, and Cochrane Library) and 2 specific Chinese databases (China National Knowledge Infrastructure (CNKI) and WanFang databases). Additionally, we intend to explore the Clinical Trials.gov, reference lists of identified publication and the grey literature. Accordingly, we will use 2 independent authors to screen the literature, extract data, and research quality assessment. We will carry out all statistical analyses using RevMan 5.3 software. RESULTS: We will systematically evaluate the clinical therapeutic effects of vitamin D supplementation to enhance children with bone mineral density. CONCLUSION: The present study will summarise the currently published pieces of evidence of vitamin D supplementation for bone mineral density in children to further comprehend its promotion and application. ETHICS AND DISSEMINATION: The present study is a systematic review and meta-analysis founded upon existing or published studies; therefore, ethical approval is not applicable. OSF REGISTRATION NUMBER: October 24, 2020. osf.io/7vtey. (https://osf.io/7vtey/).

Potassium fertilization combined with crop straw incorporation alters soil potassium fractions and availability in northwest China: An incubation study.

Potassium (K) input is essential for the improvement of soil fertility in agricultural systems. However, organic amendment may differ from mineral K fertilization with respect to modifying the soil K transformation among different fractions, affecting soil K availability. We conducted a 60-day lab incubation experiment to evaluate the response of soil K dynamics and availability in various fractions with a view to simulating crop residue return and chemical K fertilization in an Anthrosol of northwest China. The tested soil was divided into two main groups, no K fertilization (K0) and K fertilization (K1), each of which was subjected to four straw addition regimes: no straw addition (Control), wheat straw addition (WS), maize straw addition (MS), and both wheat straw and maize straw addition (WS+MS). Soil K levels in the available (AK) and non-exchangeable (NEK) fractions were both significantly increased after K addition, following the order of K>WS>MS. Fertilizer K was the most efficient K source, demonstrating a 72.9% efficiency in increasing soil AK, while wheat and maize straw exhibited efficiencies of 47.1% and 39.3%, respectively. Furthermore, K fertilization and wheat and maize straw addition increased the soil AK in a cumulative manner when used in combination. The mobility factor (MF) and reduced partition index (IR) of soil K were used to quantitate the comprehensive soil K mobility and stability, respectively. Positive relationships were observed between the MF and all relatively available fractions of soil K, whereas the IR value of soil K correlated negatively with both MF and all available fractions of soil K. In conclusion, straw amendment could be inferior to mineral K fertilization in improving soil K availability when they were almost equal in the net K input. Crop straw return coupled with K fertilization can be a promising strategy for improving both soil K availability and cycling in soil-plant systems.

Fast room-temperature self-healing siloxane elastomer for healable stretchable electronics.

Siloxane elastomers having simultaneously high stretchability, fast and efficient self-healing abilities at room temperature and excellent mechanical properties have broad application prospects in many fields. However, it is still challenging to satisfy this request. In this work, a stretchable, fast self-healing siloxane elastomer was successfully synthesized by introducing aromatic disulfides into a siloxane matrix. The resulting siloxane elastomer exhibited a tensile stress of 0.5 MPa, an elongation at break over 1000%, and a healing efficiency above 95% at room temperature. The healed siloxane elastomer could recover an elongation at break of 357 ± 15% after healing for only one minute at room temperature. A healing efficiency higher than 90% was achieved even after surface aging or by overlap contact, which was due to the presence of the dynamic disulfide bonds. Furthermore, the elastomer was successfully deployed as the substrate for self-healing stretchable electronics. As a proof-of-concept, stretchable electrode and stretchable strain sensors were produced, and they all showed high stretchability, fast self-healing properties at room temperature and high durability and stability, paving the way to promising applications in stretchable and wearable electronics.

QTL mapping for quality traits using a high-density genetic map of wheat.

Protein- and starch-related quality traits, which are quantitatively inherited and significantly influenced by the environment, are critical determinants of the end-use quality of wheat. We constructed a high-density genetic map containing 10,739 loci (5,399 unique loci) using a set of 184 recombinant inbred lines (RILs) derived from a cross of 'Tainong 18 × Linmai 6' (TL-RILs). In this study, a quantitative trait loci (QTLs) analysis was used to examine the genetic control of grain protein content, sedimentation value, farinograph parameters, falling number and the performance of the starch pasting properties using TL-RILs grown in a field for three years. A total of 106 QTLs for 13 quality traits were detected, distributed on the 21 chromosomes. Of these, 38 and 68 QTLs for protein- and starch-related traits, respectively, were detected in three environments and their average values (AV). Twenty-six relatively high-frequency QTLs (RHF-QTLs) that were detected in more than two environments. Twelve stable QTL clusters containing at least one RHF-QTL were detected and classified into three types: detected only for protein-related traits (type I), detected only for starch-related traits (type II), and detected for both protein- and starch-related traits (type III). A total of 339 markers flanked with 11 QTL clusters (all except C6), were found to be highly homologous with 282 high confidence (HC) and 57 low confidence (LC) candidate genes based on IWGSC RefSeq v 1.0. These stable QTLs and RHF-QTLs, especially those grouped into clusters, are credible and should be given priority for QTL fine-mapping and identification of candidate genes with which to explain the molecular mechanisms of quality development and inform marker-assisted breeding in the future.

Concurrent Hearing and Genetic Screening of 180,469 Neonates with Follow-up in Beijing, China.

Concurrent hearing and genetic screening of newborns is expected to play important roles not only in early detection and diagnosis of congenital deafness, which triggers intervention, but also in predicting late-onset and progressive hearing loss and identifying individuals who are at risk of drug-induced HL. Concurrent hearing and genetic screening in the whole newborn population in Beijing was launched in January 2012. This study included 180,469 infants born in Beijing between April 2013 and March 2014, with last follow-up on February 24, 2018. Hearing screening was performed using transiently evoked otoacoustic emission (TEOAE) and automated auditory brainstem response (AABR). For genetic testing, dried blood spots were collected and nine variants in four genes, GJB2, SLC26A4, mtDNA 12S rRNA, and GJB3, were screened using a DNA microarray platform. Of the 180,469 infants, 1,915 (1.061%) were referred bilaterally or unilaterally for hearing screening; 8,136 (4.508%) were positive for genetic screening (heterozygote, homozygote, or compound heterozygote and mtDNA homoplasmy or heteroplasmy), among whom 7,896 (4.375%) passed hearing screening. Forty (0.022%) infants carried two variants in GJB2 or SLC26A4 (homozygote or compound heterozygote) and 10 of those infants passed newborn hearing screening. In total, 409 (0.227%) infants carried the mtDNA 12S rRNA variant (m.1555A>G or m.1494C>T), and 405 of them passed newborn hearing screening. In this cohort study, 25% of infants with pathogenic combinations of GJB2 or SLC26A4 variants and 99% of infants with an m.1555A>G or m.1494C>T variant passed routine newborn hearing screening, indicating that concurrent screening provides a more comprehensive approach for management of congenital deafness and prevention of ototoxicity.

Rhinophore bio-inspired stretchable and programmable electrochemical sensor.

Rhinophore, a bio-chemical sensory organ with soft and stretchable/retractable features in many marine molluscs species, exhibits tunable chemosensory abilities in terms of far/near-field chemical detection and molecules' source orientation. However, existing artificial bio-chemical sensors cannot provide tunable modality sensing. Inspired by the anatomical units (folded sensory epithelium) and the functions of a rhinophore, this work introduces a stretchable electrochemical sensor that offers a programmable electro-catalytic performance towards glucose based on the fold/unfold regulation of the gold nanomembrane on an elastic fiber. Geometrical design rationale and covalent bonding strategy are used to realize the robust mechanical and electrical stability of this stretchable bionic sensor. Electrochemical tests demonstrated that the sensitivities of the as-prepared bionic sensor exhibit a linear relationship with its strain states from 0% to 150%. Bio-inspired sensory functions are tested by regulating the strain of the bionic sensor. The sensor achieves a sensitivity of 195.4 µA mM-1 in a low glucose concentration range of 8-206 µM at 150% strain for potentially far-field chemical detection, and a sensitivity of 14.2 µA mM-1 in a high concentration range of 10-100 mM at 0% strain for near-field chemical detection. Moreover, the bionic sensor performs the detection while extending its length can largely enhance the response signal, which is used to distinguish the molecules' source direction. This proposed bionic sensor can be useful in wearable devices, robotics and bionics applications which require diverse modality sensing and smart chemical tracking system.

Stretchable, self-healing, transient macromolecular elastomeric gel for wearable electronics.

Flexible and stretchable electronics are emerging in mainstream technologies and represent promising directions for future lifestyles. Multifunctional stretchable materials with a self-healing ability to resist mechanical damage are highly desirable but remain challenging to create. Here, we report a stretchable macromolecular elastomeric gel with the unique abilities of not only self-healing but also transient properties at room temperature. By inserting small molecule glycerol into hydroxyethylcellulose (HEC), forming a glycerol/hydroxyethylcellulose (GHEC) macromolecular elastomeric gel, dynamic hydrogen bonds occur between the HEC chain and the guest small glycerol molecules, which endows the GHEC with an excellent stretchability (304%) and a self-healing ability under ambient conditions. Additionally, the GHEC elastomeric gel is completely water-soluble, and its degradation rate can be tuned by adjusting the HEC molecular weight and the ratio of the HEC to glycerol. We demonstrate several flexible and stretchable electronics devices, such as self-healing conductors, transient transistors, and electronic skins for robots based on the GHEC elastomeric gel to illustrate its multiple functions.

Bioinspired Flexible Volatile Organic Compounds Sensor Based on Dynamic Surface Wrinkling with Dual-Signal Response.

Living systems can respond to external stimuli by dynamic interface changes. Moreover, natural wrinkle structures allow the surface to switch dynamically and reversibly from flat to rough in response to specific stimuli. Artificial wrinkle structures have been developed for applications such as optical devices, mechanical sensors, and microfluidic devices. However, chemical molecule-triggered flexible sensors based on dynamic surface wrinkling have not been demonstrated. Inspired by human skin wrinkling, herein, a volatile organic compound (VOC)-responsive flexible sensor with a switchable dual-signal response (transparency and resistance) is achieved based on a multilayered Ag nanowire (AgNW)/SiOx /polydimethylsiloxane (PDMS) film. Wrinkle structures can form dynamically in response to VOC vapors (such as ethanol, toluene, acetone, formaldehyde, and methanol) due to the instability of the multilayer induced by their different swelling capabilities. By controlling the modulus of PDMS and the thickness of the SiOx layer, tunable sensitivities in resistance and transparency of the device are achieved. Additionally, the proximity mechanism of the solubility parameter is proposed, which explains the high selectivity of the device toward ethanol vapor compared with that of other VOCs well. This stimuli-responsive sensor exhibits the dynamic visual feedback and the quantitative electrical signal, which provide a novel approach for developing smart flexible electronics.

Building a comprehensive syntactic and semantic corpus of Chinese clinical texts.

OBJECTIVE: To build a comprehensive corpus covering syntactic and semantic annotations of Chinese clinical texts with corresponding annotation guidelines and methods as well as to develop tools trained on the annotated corpus, which supplies baselines for research on Chinese texts in the clinical domain. MATERIALS AND METHODS: An iterative annotation method was proposed to train annotators and to develop annotation guidelines. Then, by using annotation quality assurance measures, a comprehensive corpus was built, containing annotations of part-of-speech (POS) tags, syntactic tags, entities, assertions, and relations. Inter-annotator agreement (IAA) was calculated to evaluate the annotation quality and a Chinese clinical text processing and information extraction system (CCTPIES) was developed based on our annotated corpus. RESULTS: The syntactic corpus consists of 138 Chinese clinical documents with 47,426 tokens and 2612 full parsing trees, while the semantic corpus includes 992 documents that annotated 39,511 entities with their assertions and 7693 relations. IAA evaluation shows that this comprehensive corpus is of good quality, and the system modules are effective. DISCUSSION: The annotated corpus makes a considerable contribution to natural language processing (NLP) research into Chinese texts in the clinical domain. However, this corpus has a number of limitations. Some additional types of clinical text should be introduced to improve corpus coverage and active learning methods should be utilized to promote annotation efficiency. CONCLUSIONS: In this study, several annotation guidelines and an annotation method for Chinese clinical texts were proposed, and a comprehensive corpus with its NLP modules were constructed, providing a foundation for further study of applying NLP techniques to Chinese texts in the clinical domain.

Genetic screening revealed usher syndrome in a paediatric Chinese patient.

INTRODUCTION: Usher syndrome is the most common cause of hereditary deaf-blindness. Three clinical subtypes have been classified. Usher syndrome type I is the most severe subtype characterized by congenital severe-to-profound hearing loss, retinitis pigmentosa and vestibular dysfunction. METHODS: One family was analyzed and the analysis included the combination of a custom capture/next-generation sequencing panel of 180 known deafness gene, Sanger sequencing and bioinformatics approaches. RESULTS: Compound heterozygous mutations in the MYO7A gene: a known missense mutation c.494C>T (p.Thr165Met) and a novel missense mutation c.6113G>A (p.Gly2038Glu) were identified in a proband. This Chinese hearing-impaired child was misdiagnosed as non-syndromic hearing loss which was later changed to the diagnosis of Usher syndrome type I after comprehensive audiometric, vestibular and ophthalmological examinations at 9 years old. CONCLUSIONS: Due to the features of genetic heterogeneity and variation in clinical manifestation, molecular diagnosis and ophthalmological examinations by skilled ophthalmologists with knowledge of Usher syndrome should be suggested as a routine assessment which may improve the accuracy and reliability of etiological diagnosis for hearing loss.

Identification of a de novo mutation of SOX10 in a Chinese patient with Waardenburg syndrome type IV.

OBJECTIVES: Waardenburg syndrome is a rare genetic disorder, characterized by the association of sensorineural hearing loss and pigmentation abnormalities. Four subtypes have been classified. The present study aimed to analyze the clinical feature and investigate the genetic cause for a Chinese case of Waardenburg type IV (WS4). METHODS: The patient and his family members were subjected to mutation detection in the candidate gene SOX10 by Sanger sequencing. RESULTS: The patient has the clinical features of WS4, including sensorineural hearing loss, bright blue irides, premature graying of the hair and Hirschsprung disease. A novel heterozygous frameshift mutation, c.752_753ins7 (p.Gly252Alafs*31) in the exon 5 of SOX10 was detected in the patient, but not found in the unaffected family members and 100 normal controls. This mutation results in a premature stop codon 31 amino acid downstream. CONCLUSIONS: The novel mutation c.752_753ins7 (p.Gly252Alafs*31) arose de novo and was considered as the cause of WS4 in the proband. This study further characterized the molecular complexity of WS4 and provided a clinical case for genotype-phenotype correlation studies of different phenotypes caused by SOX10 mutations.

Mutational analysis of the SLC26A4 gene in Chinese sporadic nonsyndromic hearing-impaired children.

OBJECTIVE: To investigate the mutations of SLC26A4 gene and the relevant phenotype in Chinese sporadic nonsyndromic hearing-impaired children. METHODS: 195 Chinese sporadic nonsyndromic hearing-impaired children were subjected to microarray-based mutation detection for 9 hot spot mutations in four of the most common deafness-related genes (GJB2, SLC26A4, GJB3, and 12s rRNA). Subsequently, twenty-one patients with one SLC26A4 mutation detected by microarray were subjected to sequencing analysis of the whole SLC26A4 coding region and the splice sites in order to identify the second mutant allele. The inner ear malformation and hearing loss level were compared among different genotypes. RESULTS: The incidence of genetic mutations was found to be 43.59% (85/195) in this patient group using CapitalBio Deafness Gene Mutation Detection Array Kit. A total of 34 children (17.44%) were found carrying the mutant SLC26A4 sequences. Thirteen (6.67%) children carried two mutant alleles of SLC26A4 and 21 (10.77%) children carried one mutant allele of SLC26A4. After the application of subsequent sequencing analysis, 13 mutational variants including 4 novel variants, two missense (p.D661G, p.N457D), one splice site mutation (IVS15+1G>A) and one frameshift mutation (624_632del9insACTTGGC), were identified in SLC26A4 gene in 15 of the 21 previously monoallelic patients. No second mutation was identified in the remaining 6 children. Biallelic mutations of SLC26A4 were identified in 20 of 21 children with enlarged vestibular aqueduct. CONCLUSIONS: Our results demonstrated that genetic factors were important causes for sporadic nonsyndromic hearing loss in Chinese pediatric cases. Mutation of SLC26A4 is one of the major genetic causes in nonsyndromic hearing loss with inner ear malformation. IVS7-2A>G, 2168A>G and 1229C>T were the most frequent mutations identified in our studies. The combination of microarray testing and sequencing analysis is a useful and high-throughput method for the diagnosis of genetic hearing loss.

Microarray-based mutation detection of pediatric sporadic nonsyndromic hearing loss in China.

OBJECTIVE: To investigate the molecular etiologic causes of sporadic nonsyndromic hearing loss in Chinese children. METHODS: 179 sporadic nonsyndromic hearing loss children were subjected to microarray-based mutation detection for nine hot spot mutations in four of the most common deafness-related genes, including GJB2, SLC26A4, GJB3, and 12s rRNA. RESULTS: The incidence of positive genetic errors was 43.58% with the current set of target genes in sporadic nonsyndromic hearing loss children. Among them, 25.14% of cases had genetic defects in GJB2, 16.76% of cases had pathogenic mutations in SLC26A4, 1.12% of cases were caused by 12s rRNA mutations, and GJB3 mutation was detected in 0.56% of this group of patients. CONCLUSIONS: Our results demonstrated that genetic factors were important causes for sporadic nonsyndromic hearing loss in Chinese pediatric cases. Mutations of GJB2 and SLC26A4 are two major genetic causes, whereas mutations of GJB3 and 12s rRNA result in the development of hearing loss in a small percentage of sporadic nonsyndromic hearing loss cases. Microarray testing is a helpful and instrumental screening method in the diagnosis of genetic hearing loss.