Computer-Aided Diagnosis of Laryngeal Cancer Based on Deep Learning with Laryngoscopic Images.

Laryngeal cancer poses a significant global health burden, with late-stage diagnoses contributing to reduced survival rates. This study explores the application of deep convolutional neural networks (DCNNs), specifically the Densenet201 architecture, in the computer-aided diagnosis of laryngeal cancer using laryngoscopic images. Our dataset comprised images from two medical centers, including benign and malignant cases, and was divided into training, internal validation, and external validation groups. We compared the performance of Densenet201 with other commonly used DCNN models and clinical assessments by experienced clinicians. Densenet201 exhibited outstanding performance, with an accuracy of 98.5% in the training cohort, 92.0% in the internal validation cohort, and 86.3% in the external validation cohort. The area under the curve (AUC) values consistently exceeded 92%, signifying robust discriminatory ability. Remarkably, Densenet201 achieved high sensitivity (98.9%) and specificity (98.2%) in the training cohort, ensuring accurate detection of both positive and negative cases. In contrast, other DCNN models displayed varying degrees of performance degradation in the external validation cohort, indicating the superiority of Densenet201. Moreover, Densenet201's performance was comparable to that of an experienced clinician (Clinician A) and outperformed another clinician (Clinician B), particularly in the external validation cohort. Statistical analysis, including the DeLong test, confirmed the significance of these performance differences. Our study demonstrates that Densenet201 is a highly accurate and reliable tool for the computer-aided diagnosis of laryngeal cancer based on laryngoscopic images. The findings underscore the potential of deep learning as a complementary tool for clinicians and the importance of incorporating advanced technology in improving diagnostic accuracy and patient care in laryngeal cancer diagnosis. Future work will involve expanding the dataset and further optimizing the deep learning model.

[Application of Rat Model of Neurotic Erectile Dysfunction in Experiment].

Erectile dysfunction (ED) refers to the persistent inability to achieve and/or maintain a sufficient erection of the penis to obtain a satisfactory sexual life,which affects the quality of life of the patients and their sexual partners.To decipher the pathophysiological mechanism of ED,researchers have established a variety of animal models and achieved a series of progress.The cavernous nerve (CN) of rodents,anatomically similar to that of humans,is cost-effective,thick,and easy to be identified,which has gradually become the mainstream of animal models.In this paper,we reviewed the modeling methods of the neurological ED caused by bilateral CN injury in rats in recent years,summarized the model evaluation indicators,and discussed the application and progress of ED models in basic experimental research.

Molecular mechanism of di-n-butyl phthalate promotion of bladder cancer development.

PURPOSE: To determine whether di-n-butyl phthalate (DBP) promotes the occurrence of bladder cancer (BCa) and explore the action of DBP acts on BCa cells at the cellular and molecular levels. METHODS: MTT and Transwell assays were used to investigate the tumorigenic actions of DBP on BCa cells. Second-generation sequencing was used to identify differences in gene expression before and after DBP treatment. Differential gene expression was verified by q-PCR and analyzed using bioinformatics. Cells were transfected to overexpress genes of interest and proliferation and migration were measured using MTT and Transwell assays, respectively. RESULTS: DBP treatment stimulated both proliferation and invasion in BCa cells. Second-generation sequencing identified differences in the expression of FOSB, JUND, ATP6V1C2, and RHOQ before and after DBP treatment. FOSB expression was confirmed by q-PCR and bioinformatic analyses. FOSB overexpression increased both proliferation and invasion in BCa cells. CONCLUSION: DBP promoted BCa tumorigenesis by inducing changes in gene expression.

A Multi-Center, Randomized, Blind, Controlled Clinical Trial of the Safety and Efficacy of Micro Radio Frequency Therapy System for the Treatment of Overactive Bladder.

Purpose: The purpose of this study was to evaluate the efficacy and safety of low power micro radiofrequency (RF) therapy (µRFthera®) through urethra in the treatment of overactive bladders (OAB) through a prospective, single-blind, placebo-controlled, multi-center clinical protocol. Materials and Methods: One hundred and fourteen patients with refractory OAB were randomized at 2:1 ratio, treatment to control undergoing same procedures except only the micro-RF treatment group at turned "on" setting in energy. Bladder diaries recorded during the screening period (3 days before enrollment) and during follow-up period on week 1, 3, and 7, respectively. The patients in control could choose receiving an energized treatment during extension stage. Results: The treatment efficacy was 76.1%. There was 49.80% rate improvement compared to control (95%CL 32.48%, 67.13%). The crude rate ration (RR) was 2.89, 95% CI (1.67-5.01) with p < 0.001 in uni-variate analysis, while the RR became 2.94, 95% CI (1.67-5.16) with p < 0.001 after adjusted potential confounding factors in multi-variate analysis. Statistically significant improvements have been demonstrated in the frequency of urination, urgency, nocturia, and quality of life (QoL) scores. Conclusions: Micro RF therapy is safe and effective for the treatment of OAB. The main treatment-related complications were catheterization related complications. Clinical Trial Registration: Zhejiang Device Registration Certificate No. 202090909, www.chictr.org.cn, Clinical Trial Accession Number: ChiCTR2100050096.

Hypoxia-inducible factor protects against acute kidney injury via the Wnt/ß-catenin signaling pathway.

Promoting adaptive repair in acute kidney injury (AKI) is an effective strategy to prevent the progression from AKI to chronic kidney disease. However, the mechanisms involved in renal repair after AKI remain unclear. In this study, we investigated the role of hypoxia-inducible factor (HIF), an important regulator of ischemic and hypoxic injury, in AKI during the repair phase. We established mouse models of ischemia-reperfusion injury-induced AKI with adaptive repair or maladaptive repair. We found that after injury, activation of HIF in the adaptive repair group was rapid, whereas in the maladaptive repair group HIF activation was relatively delayed, and its expression was significantly lower than that in the adaptive repair group during the early repair phase. To further investigate the mechanism of HIF, we regulated the expression of HIF-1α and HIF-2α in HK-2 cells and EA.hy926 cells, respectively. Silencing HIF expression reduced proliferation and increased apoptosis in cells injured by hypoxia/reoxygenation. Self-healing ability was further reduced due to the downregulation of HIF. Moreover, HIF overexpression had the opposite effect. HIF increased the expression of ß-catenin and its downstream target genes. Activation of Wnt/ß-catenin by the small-molecule activator SKL2001 mitigated the damaging effect of HIF knockdown, whereas blockade of ß-catenin with the inhibitor IWR-1-endo reduced the protective effects of HIF. In conclusion, HIF, which is highly expressed in the early stage after AKI, promotes renal repair by interacting with the Wnt/ß-catenin signaling pathway.NEW & NOTEWORTHY We investigated the role of hypoxia-inducible factor (HIF) in acute kidney injury in vivo and in vitro. Expression of HIF in the adaptive repair group was more rapid and sufficient than that in the maladaptive repair group during the early repair phase. HK-2 and EA.hy926 cells treated with hypoxia/reoxygenation were used to elucidate the cross talk between HIF and the Wnt/ß-catenin signaling pathway by which HIF played a renoprotective role in acute kidney injury.

Roxadustat treatment for anemia in peritoneal dialysis patients: A randomized controlled trial.

BACKGROUND/PURPOSE: Roxadustat, a first-in-class hypoxia-inducible factor prolyl hydroxylase inhibitor, promotes erythropoiesis and regulates iron metabolism. This study investigated the efficacy and safety of roxadustat in Chinese patients with anemia on peritoneal dialysis (PD). METHODS: One hundred and twenty-nine patients were randomized and treated with roxadustat (n = 86) or erythropoiesis-stimulating agents (ESAs) (n = 43) for 24 weeks. The primary end points were the mean hemoglobin (Hb) level at week 24, the change in average Hb levels from baseline to week 24, and the cumulative response rate throughout the treatment period. The secondary end points included changes in hepcidin and iron indices and serum lipid levels. Subgroup analysis examined the effect of inflammatory status on the efficacy of Hb. Safety was assessed as the occurrence of emergent adverse events after treatment. RESULTS: The mean average Hb levels at week 24 and average change in Hb levels from baseline to week 24 were 11.5 g/dL and 2.5 g/dL in the roxadustat group and 11.2 g/dL and 2.2 g/dL in the ESAs group, respectively. The cumulative response rate was 96% in the roxadustat group and 92% in the ESAs group at week 24. Roxadustat decreased hepcidin levels and increased total iron-binding capacity. The decreases in total cholesterol and low-density lipoprotein cholesterol were greater with roxadustat than with ESAs. Roxadustat-induced Hb increases were independent of baseline C-reactive protein levels. Common adverse events included hyperkalemia, hypertension, and insomnia. CONCLUSION: Roxadustat effectively corrected and maintained target Hb levels in Chinese PD patients. This trial was registered in the Chinese Clinical Trial Register (ChiCTR2000035054).

Bioinformatic Analysis Combined With Experimental Validation Reveals Novel Hub Genes and Pathways Associated With Focal Segmental Glomerulosclerosis.

Background: Focal segmental glomerulosclerosis (FSGS) is a type of nephrotic syndrome leading to end-stage renal disease, and this study aimed to explore the hub genes and pathways associated with FSGS to identify potential diagnostic and therapeutic targets. Methods: We downloaded the microarray datasets GSE121233 and GSE129973 from the Gene Expression Omnibus (GEO) database. The datasets comprise 25 FSGS samples and 25 normal samples. The differential expression genes (DEGs) were identified using the R package "limma". Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the database for Annotation, Visualization and Integrated Discovery (DAVID) to identify the pathways and functional annotation of the DEGs. The protein-protein interaction (PPI) was constructed based on the Search Tool for the Retrieval of Interacting Genes (STRING) database and visualized using Cytoscape software. The hub genes of the DEGs were then evaluated using the cytoHubba plugin of Cytoscape. The expression of the hub genes was validated by quantitative real-time polymerase chain reaction (qRT-PCR) using the FSGS rat model, and receiver operating characteristic (ROC) curve analysis was performed to validate the accuracy of these hub genes. Results: A total of 45 DEGs including 18 upregulated and 27 downregulated DEGs, were identified in the two GSE datasets (GSE121233 and GSE129973). Among them, five hub genes with a high degree of connectivity were selected. From the PPI network, of the top five hub genes, FN1 was upregulated, while ALB, EGF, TTR, and KNG1 were downregulated. The qRT-PCR analysis of FSGS rats confirmed that the expression of FN1 was upregulated and that of EGF and TTR was downregulated. The ROC analysis indicated that FN1, EGF, and TTR showed considerable diagnostic efficiency for FSGS. Conclusion: Three novel FSGS-specific genes were identified through bioinformatic analysis combined with experimental validation, which may promote our understanding of the molecular underpinning of FSGS and provide potential therapeutic targets for the clinical management.

Clinical outcomes of sacral neuromodulation in non-neurogenic, non-obstructive dysuria: A 5-year retrospective, multicentre study in China.

BACKGROUND: Management of non-neurogenic, non-obstructive dysuria represents one of the most challenging dilemmas in urological practice. The main clinical symptom is the increase in residual urine. Voiding dysfunction is the main cause of dysuria or urinary retention, mainly due to the decrease in bladder contraction (the decrease in contraction amplitude or duration) or the increase in outflow tract resistance. Sacral neuromodulation (SNM) has been used for > 10 years to treat many kinds of lower urinary tract dysfunction. It has become increasingly popular in China in recent years. Consequently, studies focusing on non-neurogenic, non-obstructive dysuria patients treated by SNM are highly desirable. AIM: To assess the outcome of two-stage SNM in non-neurogenic, non-obstructive dysuria. METHODS: Clinical data of 54 patients (26 men, 28 women) with non-neurogenic, non-obstructive dysuria treated by SNM from January 2012 to December 2016 in ten medical centers in China were retrospectively analyzed. All patients received two or more conservative treatments. The voiding diary, urgency score, and quality of life score before operation, after implantation of tined lead in stage I (test period), and during short-term follow-up (latest follow-up) after implantation of the implanted pulse generator in stage II were compared to observe symptom improvements. RESULTS: Among the 54 study patients, eight refused to implant an implanted pulse generator because of the unsatisfactory effect, and 46 chose to embed the implanted pulse generator at the end of stage I. The conversion rate of stage I to stage II was 85.2%. The average follow-up time was 18.6 mo. There were significant differences between baseline (before stage I) and the test period (after stage I) in residual urine, voiding frequency, average voiding amount, maximum voiding amount, nocturia, urgency score, and quality of life score. The residual urine and urgency score between the test period and the latest follow-up time (after stage II) were also significantly different. No significant differences were observed for other parameters. No wound infection, electrode breakage, or other irreversible adverse events occurred. CONCLUSION: SNM is effective for patients with non-neurogenic, non-obstructive dysuria showing a poor response to traditional treatment. The duration of continuous stimulation may be positively correlated with the improvement of residual urine.

[Effects of Different Concentrations of Ammonia Nitrogen on the Growth and Enzyme Activity of Four Common Algae Strains].

Treating swine wastewater with a high ammonia nitrogen content with microalgae cultures has proved difficult. In this paper, the strains Chlamydomonas 715, Botryococcus braunii 357, Porphyridium cruentum 806, and Scenedesmus obliquus 417 were tested. Ammonia nitrogen concentrations of 50 mg·L-1, 500 mg·L-1, and 2000 mg·L-1 applied to the media according to the concentrations of biogas slurry. This allowed the effect of different concentrations of ammonia nitrogen on the growth and cell enzyme activity of microalgae to be tested. The results showed that the growth of Chlamydomonas 715 and Scenedesmus obliquus 417 was inhibited at different concentrations of ammonia nitrogen, and the biomass and biomass productivities were lower than for the normal media. However, the biomass and biomass productivity of Porphyridium cruentum 806 in 50 mg·L-1 ammonia nitrogen were 1.78 g·L-1 and 0.16 g·(L·d)-1, respectively, which were higher than the values obtained using KOCK medium. Furthermore, the biomass and biomass productivity of Botryococcus braunii 357 in 500 mg·L-1 ammonia nitrogen were 1.95 g·L-1 and 0.18 g·(L·d)-1, respectively, which were higher than the values obtained using BG11 medium. The SOD, POD, and CAT of all algae species showed a decreasing tendency in response to an increase in the concentration of ammonia nitrogen, as did MDA. These results provide a theoretical basis for the treatment of swine wastewater with high ammonia nitrogen content using microalgae cultures.

Results of Sacral Neuromodulation Therapy for Urinary Voiding Dysfunction: Five-Year Experience of a Retrospective, Multicenter Study in China.

PURPOSE: This five-year, retrospective, multicenter study evaluated the long-term safety and efficiency of sacral neuromodulation (SNM) in Chinese patients with urinary voiding dysfunction. PATIENTS AND METHODS: This is a Chinese national, multicenter, retrospective study that included 247 patients (51.2% female) who received an implantable pulse generator (IPG) (InterStim, Medtronic, Minneapolis, MN, USA) between 2012 and 2016. Success was considered if the initial ≥50% improvement in any of primary voiding diary variables persisted compared with baseline. The results were further stratified by identifying patients who showed >50% improvement and those although showed <50% improvement but still wanted to receive IPG; these data were collected and analyzed for general improvement. RESULTS: Following test stimulation, 187 patients (43%) declined implantation and 247 (57%) underwent implantation using InterStim®. Among 247 patients, 34 (13.7%) had overactive bladder (OAB), 59 (23.8%) had interstitial cystitis/bladder pain syndrome (IC/BPS), 47 (19%) had idiopathic urinary retention (IUR), and 107 (44.1%) had neurogenic bladder (NB). IPG efficiency rate for OAB, interstitial cystitis/bladder pain syndrome, idiopathic urinary retention, and neurogenic bladder were 42.5, 72.4, 51.6, and 58.8%, respectively. The mean duration of follow-up was 20.1 ± 12.8 months. CONCLUSIONS: SNM appears effective in the long term, with a total IPG implantation rate of approximately 57% (ranging between 42.5 and 72.4% depending on indication). Interstitial cystitis/bladder pain syndrome appear to be the best indication for stage I testing. Chinese neurogenic bladder patients are most inclined to choose SNM. SNM is relatively safe, with low postoperation adverse events of 16.1% and reoperation rate of 3.2% during the follow-up period.

[Efficacy of Huang'e Capsules on benign prostatic hyperplasia with Qi-deficiency, blood stasis and damp heat block: A stratified analysis].

OBJECTIVE: To evaluate the efficacy and safety of Huang'e Capsules in the treatment of BPH with Qi-deficiency, blood stasis and damp heat block. METHODS: This study included 1 456 cases of BPH with Qi-deficiency, blood stasis and damp heat block from 40 hospitals of Zhejiang and Anhui Provinces between June 2014 and July 2017. The patients were aged 40－85 years and treated with Huang'e Capsules at a dose of 4 capsules, tid, for a course of 6 weeks. The IPSSs of the patients were obtained before and after 2, 4 and 6 weeks of medication, and a stratified analysis was made on the factors influencing the therapeutic effects, such as age, the stage of BPH, and concomitant medication of urogenital and reproductive hormone drugs. RESULTS: After 6 weeks of medication, the IPSS of the patients was decreased by 8.4 ± 5.4 (ï¼»42.9 ± 22.7ï¼½ %) as compared with the baseline (19.2 ± 6.8) (P < 0.05), with a total effectiveness rate of 71.9% and an excellence rate of 23.1%. After 6 weeks of medication, the IPSSs of the patients with stage-Ⅰ, -Ⅱ and -Ⅲ BPH were decreased by 7.3 ± 6.8, 6.6 ± 4.3 and 11.0 ± 5.5, with total effective rates of 69.5%, 70.1% and 74.7%, respectively, with statistically significant differences among the three stages (P < 0.05), and so were those in the patients aged ≤50 years (by 7.4 ± 5.8), 51－60 years (by 7.9 ± 5.3), 61－70 years (by 8.7 ± 5.6) and >70 years (by 8.6 ± 5.1), but with no statistically significant differences among different age groups (P > 0.05). At 6 weeks, the IPSS was reduced by 7.1 ± 5.9 by concomitant medication of urogenital and reproductive hormone drugs, 8.7 ± 5.4 by concomitant medication of other drugs, and 8.4 ± 5.3 by non-concomitant medication, with no statistically significant differences among the three types of medication (P > 0.05). CONCLUSIONS: Huang'e Capsules can evidently improve the symptoms of BPH, with the best effect on stage-Ⅲ BPH, and the effect does not differ significantly with age or drug concomitance.

[Hypospadias induced by maternal exposure to di-n-butyl phthalate and its mechanisms in male rat offspring , , , , ,].

OBJECTIVE: To induce hypospadias in male rat offspring by maternal exposure to di-n-butyl phthalate (DBP) during late pregnancy and further investigate its mechanisms. METHODS: We randomly divided 20 pregnant rats into a DBP exposure and a control group, the former treated intragastrically with DBP while the latter with soybean oil at 750 mg per kilogram of the body weight per day from gestation days (GD) 14 to 18. On postnatal day (PND) 1, we recorded the incidence rate of hypospadias and observed the histopathological changes in the genital tubercle of the hypospadiac rats. We also measured the level of serum testosterone (T) by radioimmunoassay and determined the mRNA and protein expressions of the androgen receptor (AR), sonic hedgehog (Shh), bone morphogenetic protein 4 (Bmp4) and fibroblast growth factor 8 (Fgf8) in the genital tubercle by real-time PCR and Western blot. RESULTS: No hypospadiac male rats were found in the control group. The incidence rate of hypospadias in male offspring was 43.6% in the DBP-treatment group. Histological analysis confirmed hypospadiac malformation. The serum testosterone concentration was decreased in the hypospadiac male rats as compared with the controls (ï¼»0.49 ± 0.05ï¼½ vs ï¼»1.12 ± 0.05ï¼½ ng/ml, P <0.05). The mRNA expressions of AR, Shh, Bmp4 and Fgf8 in the genital tubercle were significantly lower in the hypospadiac male rats than in the controls (AR: 0.50 ± 0.05 vs 1.00 ± 0.12, P <0.05; Shh: 0.65 ± 0.07 vs 1.00 ± 0.15, P <0.05; Bmp4: 0.42 ± 0.05 vs 1.00 ± 0.13, P <0.05; Fgf8: 0.46 ± 0.04 vs 1.00 ± 0.12, P <0.05), and so were their protein expressions (AR: 0.34 ± 0.05 vs 1.00 ± 0.09, P <0.05; Shh: 0.51 ± 0.07 vs 1.00 ± 0.12, P <0.05; Bmp4: 0.43 ± 0.05 vs 1.00 ± 0.11, P <0.05; Fgf8: 0.57 ± 0.04 vs 1.00 ± 0.13, P <0.05). CONCLUSIONS: Maternal exposure to DBP during late pregnancy can induce hypospadias in the male rat offspring. DBP affects the development of the genital tubercle by reducing the serum T concentration and expressions of AR, Shh, Bmp4 and Fgf8 in the genital tubercle, which might underlie the mechanism of DBP inducing hypospadias.

In situ observation of fracture behavior of canine cortical bone under bending.

Cortical bone provides many important body functions and maintains the rigidness and elasticity of bone. A common failure mode for bone structure is fracture under a bending force. In the current study, the fracture behavior of canine cortical bone under three-point bending was observed in situ using an atomic force microscope (AFM), a scanning electron microscope (SEM), and an optical microscope to examine the fracture process in detail. Nanoindentation was carried out to determine the elastic modulus and hardness of different building blocks of the canine cortical bone. The results have shown that the special structure of Haversian systems has significant effects on directing crack propagation. Although Haversian systems contain previously believed weak points, and micro-cracks initiate within Haversian systems, our findings have demonstrated that macro-cracks typically form around the boundaries of Haversian systems, i.e. the cement lines. Micro-cracks that developed inside Haversian systems have the functions of absorbing and dissipating energy and slow down on expanding when interstitial tissue cannot hold any more pressure, then plastic deformation and fracture occur.

Complete mitochondrial genome sequence and mutations of the laryngeal cancer model inbred nude rat strain.

In the present work, we undertook the complete mitochondrial genome sequencing of an important laryngeal cancer model inbred rat strain for the first time. The total length of the mitogenome was 16,308 bp. It harbored 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and one non-coding control region (D-loop region). The mutation events were also reported.

[Biosynthetic schwertmannite as catalyst in Fenton-like reactions for degradation of methyl orange].

Biosynthesized schwertmannite was used as catalyst in photo-Fenton-like reaction to facilitate the degradation of methyl orange (MO). Schwertmannite was synthesized through the oxidation of FeSO4 by Acidithiobacillus ferrooxidans LX5 cell suspension at an initial pH 2.5 and 28 degress C for 3 days and characterized using X-ray diffraction spectroscopy and scanning electron microscope. The oxidative degradation of MO in the photo-Fenton-like reaction was studied at different initial pH values of suspension, concentrations of H2O2 and dosages of catalyst. The results suggested that the biosynthetic schwertmannite showed a good catalytic activity in the MO degradation via *OH radical mechanism. Considerable degradation efficiency of MO was still obtained in approximately neutral condition or in the presence of high concentrations of chloride, sulfate and nitrate. This work demonstrated that the heterogeneous photo-Fenton-like reaction catalyzed by the biosynthetic schwertmannite is a promising advanced oxidation technology for the treatment of wastewater containing MO.

[Photochemical degradation of landfill leachate facilitated by combined schwertmannite and H2O2].

It is practically important that high concentrations of organic pollutants in landfill leachate were degraded by a rapid and efficient approach. The influence of operating conditions such as schwertmannite dosage, V(H2O2)/m (schwertmannite) ratio on the degradation efficiency of color, TOC and COD contents of landfill leachate, was investigated by using the schwertmannite/H2O2/UV process. It was demonstrated that the color, TOC and COD removal efficiencies increased significantly with the increase in schwertmannite dosage, and then were approximately stable. However, COD removal efficiency declined because of the presence of the residual H2O2 when V (H2O2)/m (schwertmannite) was greater than 2, and the best removal efficiency of COD was 44.9%. Furthermore, high-intensity ultraviolet was more conducive to eliminate pollutants through photochemical oxidation with schwertmannite/H2O2. The color, TOC and COD removal efficiencies were 90.0%, 78.8% and 52.6% respectively after 2.5 hours of photochemical degradation, with UV-500 W under optimal initial pH = 2.5; meanwhile, this study found that it was beneficial to the photochemical degradation of leachate at room temperature via the schwertmannite/H2O2/UV process, and COD removal efficiency declined gradually when the temperature was higher than 25 degrees C. Controlled trials showed that the schwertmannite/H2O2 method was conducive to the removal of color compared with the traditional homogeneous Fenton reaction.

Multiscale hierarchical assembly strategy and mechanical prowess in conch shells (Busycon carica).

Seashells are natural body armors with superior mechanical strength and ultra-high toughness compared with their major constituent counterparts. What building blocks and architecture render seashells such mechanical prowess? In this study, micro/nanoscale structural and mechanical characterization of conch shells (Busycon carica) has been carried out. Here we show direct evidence that the previously claimed single-crystal third-order lamellae--the basic building blocks in conch shells are essentially assembled with aragonite nanoparticles of the size ranging from 20 to 45 nm. The nanoparticle-constructed third-order lamellae are not brittle, but ductile. The three-order crossed-lamellar architecture interlocks cracks via crack deflection along the interfaces in a three-dimensional manner, thus confining the damage in a small region. The findings advance the understanding of the mystery of conch shell's mechanical robustness, provide additional design guidelines for developing bioinspired nanomaterials, and lay a constitutive foundation for modeling the deformation behavior of seashells.

Hydrogen passivation induced dispersion of multi-walled carbon nanotubes.

A method combining hydrogen passivation and ultrasonication was developed for the first time to disperse multi-walled carbon nanotubes (MWCNTs) in ethanol solution and epoxy resin. Excellent dispersion of MWCNTs was achieved in both media. Three-point bending tests of the MWCNT/epoxy nanocomposites revealed a remarkable increase in elastic modulus with increasing MWCNT content.

Electrical self-healing of mechanically damaged zinc oxide nanobelts.

We report the observation of remarkable electrical self-healing in mechanically damaged ZnO nanobelts. Nanoindentation into intrinsically defect-free ZnO nanobelts induces deformation and crack damage, causing a dramatic electrical signal decrease. Two self-healing regimes in the nanoindented ZnO nanobelts are revealed. The physical mechanism for the observed phenomena is analyzed in terms of the nanoindentation-induced dislocations, the short-range atomic diffusion in nanostructures, and the local heating of the dislocation zone in the electrical measurement.