Automatic Detection and Association Analysis of Multiple Surface Defects on Shield Subway Tunnels.

The surface defects on a shield subway tunnel can significantly affect the serviceability of the tunnel structure and may compromise operation safety. To effectively detect multiple surface defects, this study uses a tunnel inspection trolley (TIT) based on the mobile laser scanning technique. By conducting an inspection of the shield tunnel on a metro line section, various surface defects are identified with the TIT, including water leakage defects, dislocation, spalling, cross-section deformation, etc. To explore the root causes of the surface defects, association rules between different defects are calculated using an improved Apriori algorithm. The results show that: (i) there are significant differences in different association rules for various surface defects on the shield tunnel; (ii) the average confidence of the association rule "dislocation & spalling → water leakage" is as high as 57.78%, indicating that most of the water leakage defects are caused by dislocation and spalling of the shield tunnel in the sections being inspected; (iii) the weakest rule appears at "water leakage → spalling", with an average confidence of 13%. The association analysis can be used for predicting the critical defects influencing structural reliability and operation safety, such as water leakage, and optimizing the construction and maintenance work for a shield subway tunnel.

Cytomembrane Trafficking Pathways of Connexin 26, 30, and 43.

The connexin gene family is the most prevalent gene that contributes to hearing loss. Connexins 26 and 30, encoded by GJB2 and GJB6, respectively, are the most abundantly expressed connexins in the inner ear. Connexin 43, which is encoded by GJA1, appears to be widely expressed in various organs, including the heart, skin, the brain, and the inner ear. The mutations that arise in GJB2, GJB6, and GJA1 can all result in comprehensive or non-comprehensive genetic deafness in newborns. As it is predicted that connexins include at least 20 isoforms in humans, the biosynthesis, structural composition, and degradation of connexins must be precisely regulated so that the gap junctions can properly operate. Certain mutations result in connexins possessing a faulty subcellular localization, failing to transport to the cell membrane and preventing gap junction formation, ultimately leading to connexin dysfunction and hearing loss. In this review, we provide a discussion of the transport models for connexin 43, connexins 30 and 26, mutations affecting trafficking pathways of these connexins, the existing controversies in the trafficking pathways of connexins, and the molecules involved in connexin trafficking and their functions. This review can contribute to a new way of understanding the etiological principles of connexin mutations and finding therapeutic strategies for hereditary deafness.

Hearing Screening Combined with Target Gene Panel Testing Increased Etiological Diagnostic Yield in Deaf Children.

Genetic testing is the gold standard for exploring the etiology of congenital hearing loss. Here, we enrolled 137 Chinese patients with congenital hearing loss to describe the molecular epidemiology by using 127 gene panel testing or 159 variant testing. Sixty-three deaf children received 127 gene panel testing, while seventy-four patients received 159 variant testing. By use of 127 gene panel testing, more mutant genes and variants were identified. The most frequent mutant genes were GJB2, SLC26A4, MYO15A, CDH23, and OTOF. By analyzing the patients who received 127 gene panel testing, we found that 51 deaf children carried variants which were not included in 159 variant testing. Therefore, a large number of patients would be misdiagnosed if only 159 variant testing is used. This study highlights the advantage of 127 gene panel testing, and it suggests that broader genetic testing should be done to identify the genetic etiology of congenital hearing loss.

Identification of Novel Compound Heterozygous MYO15A Mutations in Two Chinese Families with Autosomal Recessive Nonsyndromic Hearing Loss.

Congenital deafness is one of the most common causes of disability in humans, and more than half of cases are caused by genetic factors. Mutations of the MYO15A gene are the third most common cause of hereditary hearing loss. Using next-generation sequencing combined with auditory tests, two novel compound heterozygous variants c.2802_2812del/c.5681T>C and c.5681T>C/c.6340G>A in the MYO15A gene were identified in probands from two irrelevant Chinese families. Auditory phenotypes of the probands are consistent with the previously reported for recessive variants in the MYO15A gene. The two novel variants, c.2802_2812del and c.5681T>C, were identified as deleterious mutations by bioinformatics analysis. Our findings extend the MYO15A gene mutation spectrum and provide more information for rapid and precise molecular diagnosis of congenital deafness.

A Novel Spontaneous Mutation of the SOX10 Gene Associated with Waardenburg Syndrome Type II.

Waardenburg syndrome (WS), also known as auditory-pigmentary syndrome, is the most common cause of syndromic hearing loss. It is responsible for 2-5% of congenital deafness. WS is classified into four types depending on the clinical phenotypes. Currently, pathogenic mutation of PAX3, MITF, EDNRB, EDN3, SNAI2, or SOX10 can cause corresponding types of WS. Among them, SOX10 mutation is responsible for approximately 15% of type II WS or 50% of type IV WS. We report the case of a proband in a Chinese family who was diagnosed with WS type II. Whole exome sequencing (WES) of the proband detected a novel heterozygous spontaneous mutation: SOX10 c.246delC. According to analysis based on nucleic acid and amino acid sequences, this mutation may produce a truncated protein, with loss of the HMG structure domain. Therefore, this truncated protein may fail to activate the expression of the MITF gene, which regulates melanocytic development and plays a key role in WS. Our finding expands the database of SOX10 mutations associated with WS and provides more information regarding the molecular mechanism of WS.

Jervell and Lange-Nielsen Syndrome due to a Novel Compound Heterozygous KCNQ1 Mutation in a Chinese Family.

Jervell and Lange-Nielsen syndrome (JLNS) is a rare but severe autosomal recessive disease characterized by profound congenital deafness and a prolonged QTc interval (greater than 500 milliseconds) in the ECG waveforms. The prevalence of JLNS is about 1/1000000 to 1/200000 around the world. However, exceed 25% of JLNS patients suffered sudden cardiac death with kinds of triggers containing anesthesia. Approximately 90% of JLNS cases are caused by KCNQ1 gene mutations. Here, using next-generation sequencing (NGS), we identified a compound heterozygosity for two mutations c.1741A>T (novel) and c.477+5G>A (known) in KCNQ1 gene as the possible pathogenic cause of JLNS, which suggested a high risk of cardiac events in a deaf child. The hearing of this patient improved significantly with the help of cochlear implantation (CI). But life-threatening arrhythmias occurred with a trigger of anesthesia after the end of the CI surgery. Our findings extend the KCNQ1 gene mutation spectrum and contribute to the management of deaf children diagnosed with JLNS for otolaryngologists (especially cochlear implant teams).

Auditory Neuropathy Spectrum Disorder due to Two Novel Compound Heterozygous OTOF Mutations in Two Chinese Families.

Auditory neuropathy spectrum disorder (ANSD), also called auditory neuropathy (AN), is a unique type of prelingual hearing impairment. Up to 10% of deaf infants and children are affected by this disease. Mutation of the OTOF gene which encodes otoferlin is the common cause of congenital nonsyndromic ANSD. To date, over 110 mutations have been identified in the OTOF gene according to the Human Gene Mutation Database (HGMD). Here, next-generation sequencing (NGS) revealed that the compound heterozygous mutations c.4748G>A/c.2523+1G>T and c.5248G>C/c.5098G>C of the OTOF gene were present in two Chinese ANSD patients. Each patient had a known pathogenic mutation (c.4748G>A or c.5098G>C) and a novel mutation (c.2523+1G>T or c.5248G>C). Comparative amino acid sequence analysis across different species revealed that the residues at these novel mutation sites are evolutionarily highly conservative. This indicated that the novel mutations were possible causes of the disorder in the patients. Our findings extend the OTOF mutation spectrum and further confirm the role of the OTOF gene in ANSD.

Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data.

Slab track is widely used in many newly built high-speed rail (HSR) lines as it offers many advantages over ballasted tracks. However, in actual operation, slab tracks are subjected to operational and environmental factors, and structural damages are frequently reported. One of the most critical problems is temperature-induced slab-warping deformation (SWD) which can jeopardize the safety of train operation. This paper proposes an automatic slab deformation detection method in light of the track geometry measurement data, which are collected by high-speed track geometry car (HSTGC). The characteristic of track vertical irregularity is first analyzed in both time and frequency domain, and the feature of slab-warping phenomenon is observed. To quantify the severity of SWD, a slab-warping index (SWI) is established based on warping-sensitive feature extraction using discrete wavelet transform (DWT). The performance of the proposed algorithm is verified against visual inspection recorded on four sections of China HSR line, which are constructed with the China Railway Track System II (CRTSII) slab track. The results show that among the 24,806 slabs being assessed, over 94% of the slabs with warping deformation can be successfully identified by the proposed detection method. This study is expected to provide guidance for efficiently detecting and locating slab track defects, taking advantage of the massive track inspection data.

Wayside Detection of Wheel Minor Defects in High-Speed Trains by a Bayesian Blind Source Separation Method.

For high-speed trains, out-of-roundness (OOR)/defects on wheel tread with small radius deviation may suffice to give rise to severe damage on both vehicle components and track structure when they run at high speeds. It is thus highly desirable to detect the defects in a timely manner and then conduct wheel re-profiling for the defective wheels. This paper presents a wayside fiber Bragg grating (FBG)-based wheel condition monitoring system which can detect wheel tread defects online during train passage. A defect identification algorithm is developed to identify potential wheel defects with the monitoring data of rail strain response collected by the devised system. In view that minor wheel defects can only generate anomalies with low amplitude compared with the wheel load effect, advanced signal processing methods are needed to extract the defect-sensitive feature from the monitoring data. This paper explores a Bayesian blind source separation (BSS) method to decompose the rail response signal and to obtain the component that contains defect-sensitive features. After that, the potential defects are identified by analyzing anomalies in the time history based on the Chauvenet's criterion. To verify the proposed defect detection method, a blind test is conducted using a new train equipped with defective wheels. The results show that all the defects are identified and they concur well with offline wheel radius deviation measurement results. Minor defects with a radius deviation of only 0.06 mm are successfully detected.

Associations of polymorphisms in the bone morphogenetic protein-2 gene with risk and prognosis of osteosarcoma in a Chinese population.

Osteosarcoma is the most common type of bone cancer in adolescence. Bone morphogenetic protein-2 (BMP-2) plays important roles in the development of bone and cartilage and in inhibiting the tumorigenicity of cancer stem cells in human osteosarcoma cell line. The aim of this study was to examine whether polymorphisms in the BMP2 gene are associated with osteosarcoma risk and prognosis in Chinese population. Five single nucleotide polymorphisms (SNP) in the BMP2 gene were genotyped in a case-control study, including 203 osteosarcoma patients and 406 cancer-free controls. We found that rs3178250 TT genotype was associated with significant increased osteosarcoma risk (age-adjusted odds ratio (OR) = 2.06, 95% confidence intervals (CI) of 1.23-3.45) compared with CC genotype. Subjects carrying the AA genotype of rs1005464 had significant decreased cancer risk (age-adjusted OR = 0.44, 95% CI of 0.23-0.85) compared with those carrying the GG genotype. Haplotype analysis also showed that carriers of the G-T-T-G and A-T-T-G haplotypes (rs235764-rs3178250-rs235768-rs1005464) had significant increased risks of osteosarcoma (age-adjusted OR = 1.85, 95% CI of 1.28-2.66 and age-adjusted OR = 1.51, 95% CI of 1.06-2.16) compared with the G-C-T-A haplotype carriers. Besides, rs1005464 was an independent prognostic factor for osteosarcoma patients (GA vs. GG: age-adjusted hazard radio (HR) = 0.60, 95% CI of 0.36-0.99). Our data suggest that genetic mutations in the BMP2 gene are associated with osteosarcoma risk and prognosis in a Chinese population.

Effect of Heat Treatment Temperature on the Spectral Properties of Cu-Ni Coating.

Cu-Ni coatings were prepared on the surface of nickel by electrodeposition method, and Cu-Ni coatings were heat-treated in 25-900 °C. Heat-treated Cu-Ni coatings were characterized with scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDAX) and X-ray diffraction (XRD) techniques, respectively. Effects of heat treatment temperature on the spectral properties of Cu-Ni coatings were studied. The surface of Cu-Ni coating is composed of the nodules. The nodules of Cu-Ni coating surface become smaller with the increase in heat treatment temperature in 25-600 °C. The nodules of Cu-Ni coating surface become smaller and the dividing line between the nodules becomes more blurred with the increase in heat treatment temperature in 600-900 °C. The contents of copper in Cu-Ni coating decrease from 82.52 at % to 78.30 at % with the increase in heat treatment temperature in the range of 25-900 °C; the contents of nickel in Cu-Ni coating increase from 17.48 at % to 21.70 at % with the increase in heat treatment temperature in the range of 25-900 °C. The crystal structure of Cu-Ni coating is Cu0:8lNi0.19 cubic crystal structure. The crystal structure of the CuO0.81Ni0.19 becomes more complete with the increase in heat treatment temperature in 25- 300 °C. Part of crystal structure of the Cu0.81AlNi0.19 can turn Cu0.8lNi0.19 cubic crystal structure into Cu3.8Ni cubic crystal structure, and is advantageous to Cu3.8Ni (311) and Cu0.81Ni0.19 (311) growth with the increase in heat treatment temperature in 600-900 °C.

Effect of REAu on Silver Staining Results and Their UV-Vis Absorption Spectra.

La, Ce, Nd, Sm, Eu, Gd, Dy particles and gold nanoparticles were prepared. Effects of La-Au, Ce-Au, Nd-Au, Sm-Au, Eu-Au, Gd-Au and Dy-Au particles on silver staining results were studied, respectively, and UV-Vis absorption spectra of La-Au, Ce-Au, Nd-Au, Sm-Au, Eu-Au, Gd-Au and Dy-Au particles were studied. Times and colors of sports with La-Au, Ce-Au, Nd-Au, Sm-Au, Eu-Au, Gd-Au, Dy-Au particles are longer and darker than that of with gold nanoparticles, respectively. The time of sport with Nd-Au particles is as long as 30 min, which is 2.7 times as long as with gold nanoparticles. Although amount of gold nanoparticles reduced 80%, the color of sport with Nd-Au particles is darker than that of with gold nanoparticles. In 200.00-800.00 nm, La, Ce, Nd, Sm, Eu, Gd, Dy particles and gold nanoparticles has one absorption peak, respectively, and λ(max) is 275, 277, 276, 276, 278, 277, 278 and 521 nm, respectively. La-Au, Ce-Au, Nd-Au, Sm-Au, Eu-Au, Gd-Au, Dy-Au particles have two absorption peaks, respectively, λ(max)(RE) and λ(max) are 276 and 522 nm, 276 and 522 nm, 276 and 523 nm, 276 and 523 nm, 276 and 522 nm, 276 and 522 nm, 276 and 523 nm, respectively. λ(max) of Au nanoparticles and La particles occurs red moving respectively, and λ(max) of Ce, Eu, Gd and Dy particles occurs blue moving, respectively, and λ(max) of Nd and Sm particles is constant respectively. Rare earths particles and gold nanoparticles may have interaction, respectively.

[Impact of sacral nerve root resection on the erectile and ejaculatory function of the sacral tumor patient].

OBJECTIVE: To evaluate the erectile and ejaculatory function of sacral tumor patients after sacral nerve root resection and investigate the relationship of erectile and ejaculatory dysfunction (EED) with the level of sacral nerve injury. METHODS: This retrospective study included 47 male patients aged 16 to 63 (32.6 +/- 6.8) years treated by sacral tumor resection between January 2008 and August 2013. According to the levels of the sacral nerve roots spared in surgery, the patients were divided into four groups: bilateral S1-S3 (n=16), unilateral S1-S3 (n=21), unilateral S1-S2 (n=6), and unilateral S1 (n=4). The patients were followed up for 12 to 41 (27.2 +/- 10.9) months by questionnaire investigation, clinic review, and telephone calls about their erectile and ejaculatory function at 3, 6 and 12 months after surgery and in August 2013. RESULTS: In the bilateral S1-S3 group, the incidence rates of EED were 31.25% (5/16), 25% (4/16), and 12.5% (2/16) at 3, 6, and 12 months respectively after surgery, with recovery of erectile and ejaculatory function in August 2013. The incidence rates of EED in the unilateral S1-S3 group were 85.71% (18/21), 71.43% (15/21), 52.38% (11/21), and 42.86% (9/21) at 3, 6 and 12 months and in August 2013, respectively; those in the unilateral S1-S2 group were 100% (6/6), 83.33% (5/6), 83.33% (5/6), and 66.67% (4/6) at the four time points; and those in the unilateral S1 group were all 100% (4/4). No statistically significant differences were found in the incidence rate of EED among the patients of different ages or tumor types (P > 0.05). CONCLUSION: The incidence of postoperative EED in male patients treated by sacral tumor resection is closely related to the mode of operation. Sparing the S3 nerve root at least unilaterally in sacral tumor resection is essential for protecting the erectile and ejaculatory function of the patient.

Preparation of electrodeposited Mo-Ni coating and its spectral properties.

Mo-Ni coatings were prepared on Ni alloy by electrodeposition method. The properties of microhardness, wear weight loss and friction coefficients, and thermal expansion of the coatings were investigated, respectively. Mo-Ni coatings were characterized with inductively coupled plasma-atomic emission spectroscopy (ICP-AES), energy-dispersive analyses of X-ray (EDAX), scanning electron microcopy (SEM), and X-ray diffraction (XRD) techniques, respectively. Mo-Ni coating shows higher microhardness, lower wear weight loss and friction coefficient compared with those of Ni alloy. The microhardness of Mo-Ni coating is as high as 518 HV, which is 72.67% higher than that of the Ni alloy (300 HV). The wear weight losses of Mo-Ni coating is 1.94 times lower than that of Ni alloy. The friction coefficient of Ni alloy and Mo-Ni coating are 0.640 and 0.559 respectively. The physical thermal expansion curve of Ni alloy has two the peaks in the ranges of 100-120 and 570-640 degrees C respectively; and that of Ni alloy+Mo-Ni coating has one the peaks in the ranges of 570-640 degrees C. The peak of the physical thermal expansion curve of Ni alloy+Mo-Ni coating in the ranges of 570-640 degrees C is much smaller than that of the Ni alloy. Because the part of nickel was replaced by molybdenum in the Ni lattice, molybdenum decreases the lattices transformation of nickel (bcc --> fcc). The reason for the formation of the small peak of the physical thermal expansion curve of Ni alloy+Mo-Ni coating in the ranges of 595-625 degrees C is the changes of MoNi4 and MoNi from the semi-crystalline structure to the crystalline structure respectively.

Degradation of cochlear Connexin26 accelerate the development of age-related hearing loss.

The GJB2 gene, encoding Connexin26 (Cx26), is one of the most common causes of inherited deafness. Clinically, mutations in GJB2 cause congenital deafness or late-onset progressive hearing loss. Recently, it has been reported that Cx26 haploid deficiency accelerates the development of age-related hearing loss (ARHL). However, the roles of cochlear Cx26 in the hearing function of aged animals remain unclear. In this study, we revealed that the Cx26 expression was significantly reduced in the cochleae of aged mice, and further explored the underlying molecular mechanism for Cx26 degradation. Immunofluorescence co-localization results showed that Cx26 was internalized and degraded by lysosomes, which might be one of the important ways for Cx26 degradation in the cochlea of aged mice. Currently, whether the degradation of Cx26 in the cochlea leads directly to ARHL, as well as the mechanism of Cx26 degradation-related hearing loss are still unclear. To address these questions, we generated mice with Cx26 knockout in the adult cochlea as a model for the natural degradation of Cx26. Auditory brainstem response (ABR) results showed that Cx26 knockout mice exhibited high-frequency hearing loss, which gradually progressed over time. Pathological examination also revealed the degeneration of hair cells and spiral ganglions, which is similar to the phenotype of ARHL. In summary, our findings suggest that degradation of Cx26 in the cochlea accelerates the occurrence of ARHL, which may be a novel mechanism of ARHL.

Targeted Next-Generation Sequencing Identified Novel Compound Heterozygous Variants in the PTPRQ Gene Causing Autosomal Recessive Hearing Loss in a Chinese Family.

Hearing loss is among the most common congenital sensory impairments. Genetic causes account for more than 50% of the cases of congenital hearing loss. The PTPRQ gene, encoding protein tyrosine phosphatase receptor Q, plays an important role in maintaining the stereocilia structure and function of hair cells. Mutations in the PTPRQ gene have been reported to cause hereditary sensorineural hearing loss. By using next-generation sequencing and Sanger sequencing, we identified a novel compound heterozygous mutation (c.997 G > A and c.6603-3 T > G) of the PTPRQ gene in a Chinese consanguineous family. This is the first report linking these two mutations to recessive hereditary sensorineural hearing loss. These findings contribute to the understanding of the relationship between genotype and hearing phenotype of PTPRQ-related hearing loss, which may be helpful to clinical management and genetic counseling.

The protective effects of systemic dexamethasone on sensory epithelial damage and hearing loss in targeted Cx26-null mice.

Mutations in the GJB2 gene (encoding Connexin26(Cx26)) are the most common cause of hereditary deafness, accounting for about a quarter of all cases. Sensory epithelial damage is considered to be one of the main causes of deafness caused by GJB2 gene mutation. Dexamethasone (DEX) is widely used in the treatment of a variety of inner ear diseases including sudden sensorineural hearing loss (SSNHL), noise-induced hearing loss (NIHL), and deafness caused by ototoxic drugs. Whether DEX has a direct therapeutic effect on hereditary deafness, especially GJB2-related deafness, remains unclear. In this study, we revealed that DEX can effectively prevent hair cell death caused by oxidative stress in cochlear explants. Additionally, two distinct Cx26-null mouse models were established to investigate whether systemic administration of DEX alleviate the cochlear sensory epithelial injury or deafness in these models. In a specific longitudinally Cx26-null model that does not cause deafness, systemic administration of DEX prevents the degeneration of outer hair cells (OHCs) induced by Cx26 knockout. Similarly, in a targeted-Deiter's cells (DCs) Cx26-null mouse model that causes deafness, treatment with DEX can almost completely prevent OHCs loss and alleviates auditory threshold shifts at some frequencies. Additionally, we observed that DEX inhibited the recruitment of CD45-positive cells in the targeted-DCs Cx26-null mice. Taken together, our results suggest that the protective effect of dexamethasone on cochlear sensory epithelial damage and partially rescue auditory function may be related to the regulation of inner ear immune response in Cx26 deficiency mouse models.

N-Acetylcysteine Combined With Dexamethasone Treatment Improves Sudden Sensorineural Hearing Loss and Attenuates Hair Cell Death Caused by ROS Stress.

Sudden sensorineural hearing loss (SSNHL) is a common emergency in the world. Increasing evidence of imbalance of oxidant-antioxidant were found in SSNHL patients. Steroids combined with antioxidants may be a potential strategy for the treatment of SSNHL. In cochlear explant experiment, we found that N-acetylcysteine (NAC) combined with dexamethasone can effectively protect hair cells from oxidative stress when they were both at ineffective concentrations alone. A clinic trial was designed to explore whether oral NAC combined with intratympanic dexamethasone (ITD) as a salvage treatment has a better therapeutic effect. 41 patients with SSNHL were randomized to two groups. 23 patients in control group received ITD therapy alone, while 18 patient s in NAC group were treated with oral NAC and ITD. The patients were followed-up on day 1st (initiation of treatment) and day 14th. Overall, there was no statistical difference in final pure-tone threshold average (PTA) improvement between those two groups. However, a significant hearing gain at 8,000 Hz was observed in NAC group. Moreover, the hearing recovery rates of NAC group is much higher than that in control group. These results demonstrated that oral NAC in combination with ITD therapy is a more effective therapy for SSNHL than ITD alone.

F-Actin Dysplasia Involved in Organ of Corti Deformity in Gjb2 Knockdown Mouse Model.

Mutations in the GJB2 gene encoding connexin26 (Cx26) protein are one of the most common causes of hereditary deafness. Previous studies have found that different Cx26-null mouse models have severe hearing loss and deformity of the organ of Corti (OC) as well as a reduction in microtubules in pillar cells (PCs). To explore the underlying mechanism of OC deformity caused by Cx26 downregulation further, we established Cx26 knockdown (KD) mouse models at postnatal days (P)0 and P8. The actin filaments contained in the pillar cells of mice in the P0 KD group were reduced by 54.85% and vinculin was increased by 22%, while the outer hair cells (OHCs) showed normal F-actin content. In the P8 KD group, PCs and OHCs of mice also showed almost normal F-actin content. The G-actin/F-actin ratio increased by 38% in the P0 KD group. No significant change was found in the mRNA or protein expression level of G-actin or the cadherin-catenin core complex in the P0 KD group at P6. Moreover, immunofluorescence showed that the intensity of LRRK2 was reduced by 97% in the P0 KD group at P6. Our results indicate that Cx26 is involved in the maturation of the cytoskeleton during the development of the OC at the early postnatal stage. The polymerization of G-actin into F-actin is prevented in Cx26 KD mice.

Sensitive osteosarcoma diagnosis through five-base telomerase product-triggered CRISPR-Cas12a enhanced rolling circle amplification.

Osteosarcoma is the most frequent primary malignant bone tumor, composed of mesenchymal cells producing osteoid and immature bone. The sensitive detection of telomerase plays a pivotal role in the early diagnosis and therapeutic treatment of osteosarcoma. We report here an in vitro strategy for sensitive telomerase activity detection through the integration of rolling circle amplification (RCA) and a clustered regularly spaced short palindrome repeats (CRISPR)-Cas12a system. In the proposed strategy, telomerase substrate (TS) primers are easily controlled to extend five bases (GGGTT) to give short telomerase extension products (TEP) with definite lengths without adding dATP. The resulting short TEPs can then cyclize the padlock through hybridizing with its two terminals and thus initiate the following RCA. To obtain an improved sensitivity, the CRISPR-Cas12a system is attached to collaterally cut surrounding DNA reporter probes after recognizing the target single strand DNA sequence in the RCA products. The highlights of this strategy are as follows: (i) the short TEP triggered strategy is excellent at detecting low telomerase activity and thus contributes to the early diagnosis of malignant tumors; (ii) highly sensitive telomerase activity detection which is easy to operate from RCA initiated CRISPR-Cas12a; (iii) opening up of a new avenue for telomerase activity detection with a CRISPR-Cas12a system. Finally, the proposed strategy exhibited sensitive telomerase activity detection under optimized experimental parameters and has great application potential for the clinical diagnosis of malignant tumors and the development of anti-cancer drugs.