Anatomical Analysis of the Cervical Sympathetic Ganglion and Spinal Ganglion and its Physiological Significance in the Pathogenesis of Cervical Vertigo

Objective

Investigating the anatomical connections between cervical sympathetic ganglia and spinal ganglia in rabbits and assessing the role of Neuropeptide Y in the pathogenesis of cervical vertigo.

Method

Part 1: 32 adult healthy male New Zealand white rabbits (whose skin is very sensitive, so rabbits are generally used for stimulation experiments) were randomly divided into the upper cervical sympathetic ganglia (SCSG) stimulation group and the lower cervical sympathetic ganglia (ICSG) stimulation group, with 16 rabbits in each group. The two groups were divided into an experimental group and a control group, with 8 rabbits in each group. The cervical ganglia of each group of white rabbits were injected with 4% FluoroGold solution and observed under a section microscope. Part 2: Sixty New Zealand white rabbits were randomly divided into a blank control (n = 12), SCSG stimulation group (n = 12), SCSG sham surgery control (n = 12), ICSG stimulation group (n = 12), and ICSG sham surgery control group (n = 12). The SCSG group and ICSG group were subjected to electrical stimulation (i.e. 30.0Hz, 10.0V, 5-minute pulse width of 0.5 ms square wave pulse), and specimens were made. The expression of NPY was detected using immunohistochemical methods.

Result

Neuropeptide Y was weakly expressed in all cervical ganglia (C1-C8). Compared with the sham surgery group, the superior cervical sympathetic ganglion stimulation group showed an increase in Neuropeptide Y positive cells in C2, C3, C4, and C5, with C2 and C3 showing the most significant increase. The number of C6, C7, and C8 Neuropeptide Y positive cells in the 3 C、3D and 4B, lower cervical sympathetic ganglion stimulated groups was higher than in the sham sham-operated group, and C6 and C7 significantly increased. Neuropeptide Y is like immunoreactive neurons in the cervical spinal ganglia, and the immunoreactive products are small brown particles distributed in the cytoplasm after electrical stimulation of the cervical sympathetic ganglia. The Neuropeptide Y content in the corresponding segment of the cervical spinal ganglia is significantly increased compared to the control group (P < .05).

Conclusion

In New Zealand white rabbits, nerve fibers are interconnected between the cervical sympathetic ganglion and the cervical spinal ganglion, and this neural fiber connection has a certain segmental nature, providing experimental basis for the existence of the cervical spinal cord external nerve reflex arc and elucidating the pathogenesis of cervical vertigo in terms of neural anatomy. By using neuroelectrophysiological methods, it has been confirmed that electrical stimulation in the cervical spinal ganglia can reach the corresponding cervical sympathetic ganglia on the same side through a certain conduction pathway, providing experimental basis in neuroelectrophysiology for the existence of the cervical extraspinal nerve reflex arc and elucidating the pathogenesis of cervical vertigo. NPY may be involved in the pathogenesis of cervical vertigo, providing a theoretical basis for the clinical diagnosis of cervical vertigo.

[Research advances on the role and mechanism of microRNA in hypertrophic scar]

Hypertrophic scar (HS) affects the function and beauty of patients, and brings a heavy psychological burden to patients. However, the specific pathogenesis mechanism of HS in molecular biology level is not yet clear, and this disease is still one of the clinical diseases difficult to prevent and cure. MicroRNA (miR) is a family of single-stranded endogenous noncoding RNAs that can regulate gene expression. The abnormal transcription of miR in hypertrophic scar fibroblasts can affect the transduction and expression of downstream signal pathway or protein, and the exploration of miR and its downstream signal pathway and protein helps deeply understand the occurrence and development mechanism of scar hyperplasia. This article summarized and analyzed how miR and multiple signal pathways involve in the formation and development of HS in recent years, and further outlined the interaction between miR and target genes in HS.

Association of oxidative stress and Kashin-Beck disease integrated Meta and Bioinformatics analysis

OBJECTIVE

To explore the association between oxidative stress (OS) and Kashin-Beck disease (KBD).

METHODS

Terms associated with "KBD" and "OS" were searched in the six different databases up to October 2021. Stata 14.0 was used to pool the means and standard deviations using random-effect or fixed-effect model. The differentially expressed genes in the articular chondrocytes of KBD were identified, the OS related genes were identified by blasting with the GeneCards. The KEGG pathway and gene ontology enrichment analysis was conducted using STRING.

RESULTS

The pooled SMD and 95% CI showed hair selenium (-4.59; -6.99, -2.19), blood selenium (-1.65; -2.86, -0.44) and glutathione peroxidases (-4.15; -6.97, -1.33) levels were decreased in KBD, whereas the malondialdehyde (1.12; 0.60, 1.64), nitric oxide (2.29; 1.31, 3.27), nitric oxide synthase (1.07; 0.81, 1.33) and inducible nitric oxide synthase (1.69; 0.62, 2.77) were increased compared with external controls. Meanwhile, hair selenium (-2.71; -5.32, -0.10) and glutathione peroxidases (-1.00; -1.78, -0.22) in KBD were decreased, whereas the malondialdehyde (1.42; 1.04, 1.80), nitric oxide (3.08; 1.93, 4.22) and inducible nitric oxide synthase (0.81; 0.00, 1.61) were elevated compared with internal controls. Enrichment analysis revealed apoptosis was significantly correlated with KBD. The significant biological processes revealed OS induced the release of cytochrome c from mitochondria. The cellular component of OS located in the mitochondrial outer membrane.

CONCLUSIONS

The OS levels in KBD were significantly increased because of selenium deficiency, OS mainly occurred in mitochondrial outer membrane, released of cytochrome c from mitochondria, and induced apoptotic signaling pathway.

The SARS-CoV-2 rS1-E-PLGA nanovaccine and evaluation of its immune effect in BALB/c mice

OBJECTIVE

Vaccination is an important method for preventing COVID-19 infection. However, certain vaccines do not meet the current needs. To improve the vaccine effect, discard ineffective antigens, and focus on high-quality antigenic clusters, S1-E bivalent antigens were designed.

MATERIALS AND METHODS

Vaccine delivery is performed using poly (lactic-co-glycolic acid) (PLGA). Here, the recombinant S1-E (rS1-E) was covered on PLGA and injected intramuscularly into mice. In total, 48 BALB/c mice were randomly divided into six groups with 8 mice in each group. The mice received intramuscular injections. Prior to vaccination, the hydrophobicity of the rS1-E and the antigenic site of the E protein were both analysed. The morphology, zeta potential, and particle size distribution of rS1-E-PLGA were examined. Anti-S1 and anti-E antibodies were detected in mouse serum by ELISA. Neutralising an-tibodies were detected by co-incubating the pseudovirus with the obtained serum. IL-2 and TNF-α levels were also measured.

RESULTS

The designed recombinant S1-E protein was successfully coated on PLGA nanoparticles. rS1-E-PLGA nanovaccine has suitable size, shape, good stability, sustained release and other characteristics. Importantly, mice were stimulated with rS1-E-PLGA nanovaccines to produce high-titre antibodies and a good cellular immune response.

CONCLUSIONS

Our results indicate that rS1-E-PLGA nanovaccine may provide a good protective effect, and the vaccine should be further investigated in human clinical trials for use in vaccination or as a booster.

The Burden of Colorectal Cancer Attributable to Diet Low in Fiber from 1990 to 2019: A Global, Regional and National Analysis

OBJECTIVES

The colorectal cancer (CRC) burden is increasingly high. The aim of this study was to investigate temporal and geographical trends in CRC deaths and disability-adjusted life-years (DALYs) attributable to diet low in fiber globally from 1990 to 2019.

DESIGN

Cross-sectional study.

SETTING

The study based on the Global Burden of Disease Study (GBD) 2019.

PARTICIPANTS

The population comprised individuals from 204 countries and territories who were diagnosed with CRC attributable to diet low in fiber from 1990 to 2019.

MEASUREMENTS

Deaths, DALYs, age-standardized mortality rates (ASMR), and age-standardized DALY rates (ASDR) for CRC attributable to diet low in fiber were described, and estimated annual percentage change (EAPC) was further calculated to assess the burden in different regions, countries, sexes, and age groups. Additionally, we explored the association between EAPC and ASMR/ASDR (in 1990) and Human Development Index (HDI, in 2019).

RESULTS

From 1990 to 2019, global ASMR and ASDR for CRC attributable to diet low in fiber decreased slightly, but the corresponding deaths and DALYs increased by 63.37% and 51.36%, respectively. Those burden varied considerably between regions and countries. The burden was higher in high, high-middle and middle SDI regions, especially in Asia and Western Europe, but when HDI > 0.7, an increasingly rapid decline in ASMR and ASDR was revealed. Unexpectedly, many less well-developed countries within the traditionally low deaths and DALYs regions of Africa, Central Latin America, and Middle East showed gradual increases in ASMR and ASDR.

CONCLUSION

The global burden of CRC attributable to diet low in fiber has decreased over the last 30 years, but remains at a high level. It is essential for decision-makers to take targeted measures for improving population awareness and intake of dietary fiber.

[Identification of serum peptide biomarker for ovarian cancer diagnosis by Clin-TOF-II-MS combined with magnetic beads technology]

Objective: To explore the serum cyclic polypeptide biomarkers for ovarian cancer diagnosis. Methods: A total of 54 patients with epithelial ovarian cancer confirmed by pathology in Cancer Hospital, Chinese Academy of Medical Sciences from March 2018 to September 2018 were selected as the study subjects, and 40 healthy women with normal examination results in the cancer screening center were selected as the control. All of the samples were randomly divided into training set and validation set at the ratio of 1∶1 with a random number. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) combined with magnetic bead technology was used for detecting peptide profiling in serum samples to screen significantly differently expressed peptides between ovarian cancer group and control group of the training set (score>5). Receiver operating characteristic (ROC) curve analysis was used to screen differential peptide peaks with area under curve (AUC) ≥0.8, sensitivity and specificity>90% in the training set and validation set. Liquid chromatography-mass spectrometry (LC-MS/MS) was further used to determine the composition of differentially expressed peptides. Results: By comparing the peptide profiles of the two groups, 102 differential peptide peaks were initially detected in the mass-to-charge ratio range of 1 000 to 10 000. ROC curve analysis showed that there were 42 differential peptide peaks with AUC ≥0.8 in both training set and validation set, 19 of which were highly expressed in ovarian cancer group, and 23 were lowly expressed. There were 15 different peptide peaks in highly expressed ovarian cancer group with sensitivity and specificity over 90%. The mass-to-charge ratios were 7 744.27, 5 913.41, 5 329.87, 4 634.21, 4 202.02, 3 879.26, 3 273.35, 3 253.79, 3 234.34, 2 950.33, 2 664.51, 2 018.38, 1 893.37, 1 498.69 and 1 287.55. There were 15 different peptide peaks in lowly expressed ovarian cancer group with sensitivity and specificity over 90%, the mass-to-charge ratios were 9 288.46, 7 759.77, 5 925.24, 4 652.77, 4 210.42, 3 887.02, 3 279.90, 3 240.82, 2 962.15, 2 932.70, 2 022.42, 1 897.16, 1 501.69, 1 337.38 and 1 290.13. No protein composition was identified in 15 different peptide peaks in lowly expressed ovarian cancer group. The two protein compositions identified in 15 different peptide peaks in highly expressed ovarian cancer group were recombinant serglycin (SRGN) and fibinogen alpha chain (FGA), the mass-to-charge ratios of which were 1 498.696 and 5 913.417, respectively. The sensitivity and specificity of the two proteins for ovarian cancer diagnosis were 100%, 100% and 90.9%, 100%, respectively. Conclusion: SRGN and FGA are highly expressed in the serum of ovarian cancer patients, which may be potential diagnostic markers for ovarian cancer.

Antibody responses after first and second Covid-19 vaccination in patients with chronic lymphocytic leukaemia

B-cell chronic lymphocytic leukaemia (CLL) is associated with immunosuppression and patients are at increased clinical risk following SARS-CoV-2 infection. Covid-19 vaccines offer the potential for protection against severe infection but relatively little is known regarding the profile of the antibody response following first or second vaccination. We studied spike-specific antibody responses following first and/or second Covid-19 vaccination in 299 patients with CLL compared with healthy donors. 286 patients underwent extended interval (10-12 week) vaccination. 154 patients received the BNT162b2 mRNA vaccine and 145 patients received ChAdOx1. Blood samples were taken either by venepuncture or as dried blood spots on filter paper. Spike-specific antibody responses were detectable in 34% of patients with CLL after one vaccine (n = 267) compared to 94% in healthy donors with antibody titres 104-fold lower in the patient group. Antibody responses increased to 75% after second vaccine (n = 55), compared to 100% in healthy donors, although titres remained lower. Multivariate analysis showed that current treatment with BTK inhibitors or IgA deficiency were independently associated with failure to generate an antibody response after the second vaccine. This work supports the need for optimisation of vaccination strategy in patients with CLL including the potential utility of booster vaccines.

[Analysis of PARP inhibitors induced anemia in advanced and relapsed epithelial ovarian cancer]

Objective: To explore the clinical features of poly ADP-ribose polymerase (PARP) inhibitor-related anemia in advanced and relapsed epithelial ovarian cancer (EOC). Methods: Patients diagnosed with advanced or relapsed EOC and treated with PARP inhibitor at National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College between January 2015 to October 2020 were accrued. The data included PARP inhibitors, treatment details, and lab tests before treatment and during treatment were collected and the clinical characteristics of PARP inhibitor-related anemia were analyzed. Results: (1) A total of 98 patients with a median age of 56.5 years old (30-82 years old) were enrolled in this study. All patients were treated with PARP inhibitor (65 cases of olaparib, 17 cases of niraparib, and 16 cases of fluzoparib). The median treatment duration was 37.5 weeks (4-119 weeks). (2) The anemia rate was 40% (39/98), including 5% (5/98) of grade Ⅰ, 14% (14/98) of grade Ⅱ, 11% (11/98) of grade Ⅲ, and 9% (9/98) of grade Ⅳ. Fourteen patients with pre-treatment grade Ⅰ anemia had a higher rate of anemia events than the 80 patients without pre-treatment anemia, 7/14 vs 35% (28/80; χ²=4.281, P=0.039). (3) The median anemia occurrence time was 7.0 weeks (1-52 weeks), including 41% (16/39) of anemia cases occurred in 1-4 weeks, 26% (10/39) occurred in 5-8 weeks, 13% (5/39) occurred in 9-12 weeks, 3% (1/39) occurred in 13-16 weeks, 10% (4/39) occurred in 17-20 weeks, 8% (3/39) occurred ≥21 weeks. At the time of the lowest hemoglobulin tested, the median value of mean corpuscular volume (MCV) was 106 fl,which was higher than the up limit of normal range (100 fl), 74% (29/39) of anemia patients had an elevated MCV level; the median value of mean corpuscular hemoglobin (MCH) was 36 pg, 54% (21/39) of anemia patients had an elevated MCH level; the median value of mean corpuscular hemoglobin concentration (MCHC) was 320 g/L, 69% (27/39) of anemia patients had a higher MCHC level; 92% (36/39) of anemia patients had a normal level of serum iron; 79% (31/39) of anemia patients had a normal level of transferrin. 74% (29/39) of the anemia patients were macrocytic orthochromatic anemia. (4) Among the 39 patients with anemia, 20 patients (51%, 20/39) withhold the treatment of PARP inhibitor due to grade Ⅲ or Ⅳ anemia, including 10 patients (50%, 10/20) who resumed the PARP inhibitor treatment by suppling iron, folate, and vitamin B₁₂. The median stopping time of PARP inhibitor was 5.5 weeks (2-10 weeks), while the other 10 patients terminated the PARP inhibitor treatment for not recovering from severe anemia. Conclusions: One of the common adverse effects of PARP inhibitors is anemia, which mostly happened in the first 3 months of treatment. In the treatment of EOC, PARP inhibitor-related anemia mainly manifest as macrocytic orthochromatic anemia, and most patients with normal serum iron and transferrin.

Maintenance treatment in advanced HER2-negative gastric cancer

Survival for patients with advanced gastric cancer (GC) remains poor. Systemic chemotherapy which has reached a plateau stays the standard first-line (1L) treatment for advanced human epidermal growth-factor receptor 2 (HER2)-negative GC. To maximize the benefit of 1L treatment, the concept of maintenance treatment is constantly being explored. In advanced HER2-negative GC, current clinical guidelines do not recommend a standard maintenance therapy strategy. In addition to the monotherapy maintenance with fluorouracil after 4-6 cycles of 1L chemotherapy, some agents that are active against novel targets have been evaluated in clinical trials for maintenance treatment. Whereas most of these trials do not reach their primary endpoints, they open new horizons for the 1L treatment of advanced HER2-negative GC. Therefore, we reviewed the clinical trials in the field of maintenance treatment in advanced HER2-negative GC and discussed some of the problems in clinical trials.

The split-off terahertz radiating dipoles on thermally reduced α-V2O5 (001) surface

The trapped electron states on a pliable lattice have different localization and physical chemistry characteristics. Here, terahertz time-domain measurements suggest that the formation of vanadyl oxygen defect, in the presence of the surface potential traps and mobile charge carriers, leads to a transient charge distribution that forms terahertz radiating dipoles in V2O5. The emergence of radiating dipoles is evidenced by terahertz responses with a two-valley feature of the thermally reduced α-V2O5 (001) thin films in the temperature range of 300-700 K. The two photoconductance valleys on a several millielectron volts interval are related to two emergent split-off traps, which originate from the VO6 octahedra distortion upon the vanadyl oxygen desorption on the surface. The pliable surface lattices plays a decisive role. So long as the α-V2O5 (001) thin films are covered by a 30 nm-thick Al2O3 capping layer, the distinct two-valley feature disappears completely in the full temperature range. The terahertz radiating dipoles with a fine energy structure is potentially a new measure for charge dynamics on the α-V2O5 (001) surface.

Knockdown of exosome‑mediated lnc‑PVT1 alleviates lipopolysaccharide‑induced osteoarthritis progression by mediating the HMGB1/TLR4/NF‑κB pathway via miR‑93‑5p

Osteoarthritis is a chronic degenerative joint disease. Long non‑coding RNA plasmacytoma variant translocation 1 (PVT1) is involved in the progression of osteoarthritis and exosomes serve a central role in intercellular communication. However, whether PVT1 can be mediated by exosomes in osteoarthritis has not been reported. Whole blood was drawn from osteoarthritis patients and healthy volunteers. Lipopolysaccharide (LPS) was used to stimulate human normal chondrocytes (C28/I2) to construct a cell damage model in vitro. Protein levels were examined via western blot analysis. eThe expression of PVT1, microRNA (miR)‑93‑5p and high mobility groupprotein B1 (HMGB1) was evaluated through reverse transcription‑quantitative PCR. Cell viability and apoptosis were determined through CCK‑8 or flow cytometric assay. Inflammatory cytokines were measured via ELISA. The relationship between PVT1 or HMGB1 and miR‑93‑5p was confirmed by dual‑luciferase reporter assay. PVT1, HMGB1 and exosomal PVT1 were upregulated while miR‑93‑5p was downregulated in osteoarthritis patient serum and LPS‑induced C28/I2 cells. Exosomes from osteoarthritis patient serum and LPS‑treated C28/I2 cells increased PVT1 expression in C28/I2 cells. PVT1 depletion reversed the decrease of viability and the increase of apoptosis, inflammation responses and collagen degradation of C28/I2 cells induced by LPS. PVT1 regulated HMGB1 expression via sponging miR‑93‑5p. miR‑93‑5p inhibition abolished PVT1 silencing‑mediated viability, apoptosis, inflammation responses and collagen degradation of LPS‑stimulated C28/I2 cells. HMGB1 increase overturned miR‑93‑5p upregulation‑mediated viability, apoptosis, inflammation responses and collagen degradation of LPS‑stimulated C28/I2 cells. Furthermore, PVT1 modulated the Toll‑like receptor 4/NF‑κB pathway through an miR‑93‑5p/HMGB1 axis. In summary, exosome‑mediated PVT1 regulated LPS‑induced osteoarthritis progression by modulating the HMGB1/TLR4/NF‑κB pathway via miR‑93‑5p, providing a new route for possible osteoarthritis treatment.

Intravitreal conbercept for branch retinal vein occlusion induced macular edema: one initial injection versus three monthly injections

Background

To compare the efficacy of one initial intravitreal injection of conbercept (IVC) versus three monthly IVCs in patients with macular edema (ME) after branch retinal vein occlusion (BRVO). Both options were followed by a pro re nata (PRN) retreatment regimen.

Methods

This study retrospectively investigated and followed 60 patients with acute ME secondary to BRVO for over a year. 30 subjects received one initial injection (1 + PRN group); while, 30 received three monthly injections (3 + PRN group). The functional and anatomic outcomes were assessed during each follow-up.

Results

The general characteristics of the 60 subjects were as follows: mean [SD] age, 57.43 [13.06] years; 33 [55%] female; 36 [60%] non-ischemic form. Both groups showed a stable gain in visual acuity (VA) with similar logMAR (mean ± SD) (1 + PRN group 0.308 ± 0.399, 3 + PRN group 0.34 ± 0.352) during the first 12 months. Additionally, both groups exhibited a significant reduction in central foveal thickness (CFT) with no statistically significant difference between them (1 + PRN group 222.1 μm ± 197.1 μm, 3 + PRN group 228.4 μm ± 200.2 μm). Both treatment groups had similar improvements in logMAR and anatomic outcomes over time. The stratified analysis showed that patients with the non-ischemic form and those with the ischemic form had similar improvements in VA (0.346 ± 0.366 VS 0.29 ± 0.39, P = 0.575) during the 12 months follow-ups. The number of injections was lower in the 1 + PRN group (4.0 ± 1.6) than in the 3 + PRN group (4.7 ± 1.3) (P = 0.068). No adverse effects or unexpected safety issues were reported in either group.

Conclusions

Conbercept yielded significant improvements in VA and CFT among patients with BRVO induced ME, independent of their retinal ischemia status. The results showed that the 3 + PRN regimen do not lead to better functional outcomes or lower treatment needs in clinical practice as compared to the 1 + PRN regimen.

Functional Pathway Between Cervical Spinal and Sympathetic Ganglia: A Neurochemical Foundation Between Neck Pain and Vertigo

Background: Cervical vertigo commonly concurs in patients with neck pain, but the concurrent mechanism of these 2 symptoms still remains unclear. We previously reported a bidirectional segmental nerve fiber connection between cervical spinal and sympathetic ganglia, which provided a hypothesis that this connection between the 2 ganglia may be the anatomic basis for the concurrence of neck pain and cervical vertigo. However, this concurrent mechanism needs biochemical and functional evidence. Objectives: This study aimed to investigate a possible noradrenergic pathway between cervical spinal and sympathetic ganglia. Study Design: We performed both clinical and laboratory research. Clinical observation was a prospective case–control study. Setting: Clinical study took place in our hospital; laboratory study was in an orthopedic laboratory. Methods: Cervical lamina block therapy used in patients with cervical vertigo was clinically evaluated; norepinephrine (NE) expressions in cervical sympathetic ganglia were analyzed using immunohistochemical staining after electrical stimulation to the cervical spinal ganglia; the influence of phentolamine local injection to the vertebrobasilar artery flow was experimentally measured. Results: Cervical lamina block therapy could significantly shorten the clinical hospital stays of patients with cervical vertigo (P = 0.000) and improve vertebral artery flow (P < 0.05). NE expressions in superior cervical sympathetic ganglia (SCG) or inferior cervical sympathetic ganglia (ICG) increased significantly when ipsilateral C2 to C3 or C6 to C8 spinal ganglia were electrically stimulated, respectively. Adrenergic receptor block with phentolamine significantly inhibited the decrease of basilar artery (BA) flow induced by electrical stimulation of the cervical spinal ganglia. The change range of BA flow caused by stimulations of C2 to C3 and C6 to C8 spinal ganglia was more than that of C4 and C5. Limitations: The inpatients observed in this clinical study might be influenced by some factors including emotion, diet, sleep, and others. The limitations of the laboratory study included animal species and small sample size. Conclusions: Adrenergic system could play a part in cervical spinal ganglia altering the vertebrobasilar artery system. It could provide a neurochemical foundation between neck pain and vertigo, and that segmental functional connections exist between cervical spinal and sympathetic ganglia.

Functional Pathway Between Cervical Spinal and Sympathetic Ganglia: A Neurochemical Foundation Between Neck Pain and Vertigo

BACKGROUND

Cervical vertigo commonly concurs in patients with neck pain, but the concurrent mechanism of these 2 symptoms still remains unclear. We previously reported a bidirectional segmental nerve fiber connection between cervical spinal and sympathetic ganglia, which provided a hypothesis that this connection between the 2 ganglia may be the anatomic basis for the concurrence of neck pain and cervical vertigo. However, this concurrent mechanism needs biochemical and functional evidence.

OBJECTIVES

This study aimed to investigate a possible noradrenergic pathway between cervical spinal and sympathetic ganglia.

STUDY DESIGN

We performed both clinical and laboratory research. Clinical observation was a prospective case-control study.

SETTING

Clinical study took place in our hospital; laboratory study was in an orthopedic laboratory.

METHODS

Cervical lamina block therapy used in patients with cervical vertigo was clinically evaluated; norepinephrine (NE) expressions in cervical sympathetic ganglia were analyzed using immunohistochemical staining after electrical stimulation to the cervical spinal ganglia; the influence of phentolamine local injection to the vertebrobasilar artery flow was experimentally measured.

RESULTS

Cervical lamina block therapy could significantly shorten the clinical hospital stays of patients with cervical vertigo (P = 0.000) and improve vertebral artery flow (P < 0.05). NE expressions in superior cervical sympathetic ganglia (SCG) or inferior cervical sympathetic ganglia (ICG) increased significantly when ipsilateral C2 to C3 or C6 to C8 spinal ganglia were electrically stimulated, respectively. Adrenergic receptor block with phentolamine significantly inhibited the decrease of basilar artery (BA) flow induced by electrical stimulation of the cervical spinal ganglia. The change range of BA flow caused by stimulations of C2 to C3 and C6 to C8 spinal ganglia was more than that of C4 and C5.

LIMITATIONS

The inpatients observed in this clinical study might be influenced by some factors including emotion, diet, sleep, and others. The limitations of the laboratory study included animal species and small sample size.

CONCLUSIONS

Adrenergic system could play a part in cervical spinal ganglia altering the vertebrobasilar artery system. It could provide a neurochemical foundation between neck pain and vertigo, and that segmental functional connections exist between cervical spinal and sympathetic ganglia.

KEY WORDS

Cervical vertigo, neck pain, cervical sympathetic ganglia, cervical spinal ganglia, noradrenaline.

Risk factors of postoperative complications after emergency repair of incarcerated groin hernia for adult patients: a retrospective cohort study

Purpose

This study aimed to explore risk factors of postoperative complications for adult patients with incarcerated groin hernia (IGH).

Methods

From January 2010 to December 2017, consecutive patients undergoing emergency hernia repair for IGH in our center were retrospectively reviewed. Postoperative complications, such as surgical site infection, seroma, hernia recurrence and mortality, were investigated, with risk factors for such complications analyzed using univariate and multivariate regressions.

Results

Sixty-four patients were included, with 51 males and 13 females (mean age 65.1, range 25–98 years). Ten patients (15.6%) underwent resection of necrotic bowel and anastomosis. 43 patients (67.2%) received open tension-free herniorrhaphy with polypropylene mesh, whereas the rest (32.8%) received herniorrhaphy without mesh. The overall postoperative complication rate was 40.6% (26/64), with an incisional complication rate of 31.2% (20/64) and an infection rate of 6.2% (4/64). At a median follow-up of 32 months, hernia recurrence and mortality were recorded in five cases each (7.8%). Mesh repair was associated with decreased recurrence rate compared with non-mesh repair (2.3% vs. 19.0%, p = 0.019). Diabetes mellitus (OR 8.611, 95%CI 1.292–57.405; p = 0.026) was an independent risk factor of postoperative complications, together with chronic obstructive pulmonary disease (COPD; OR 14.365, 95%CI 1.652–127.767, p = 0.016), intestinal necrosis (OR 14.260, 95%CI 1.079–188.460, p = 0.044), and general anesthesia (OR 14.543, 95%CI 1.682–125.711, p = 0.015) as risk for incisional complications after surgery.

Conclusions

Diabetes mellitus was an independent risk factor of postoperative complications for IGH, along with COPD, intestinal necrosis and general anesthesia associated with incisional complications. The use of polypropylene mesh did not increase infection or recurrence rate in this cohort.

Exosomes: novel regulators of bone remodelling and potential therapeutic agents for orthodontics

Recent studies suggest that exosomes are involved in intercellular communication required for the maintenance of healthy bone. Exosomes are small (30-150 nm in diameter) extracellular vesicles that are formed in multivesicular bodies and are released from cells as the multivesicular bodies fuse with the plasma membrane. Regulatory exosomes have the capacity to exert profound control over target cells. They can stimulate plasma membrane receptors and are also internalized by the target cell delivering proteins, lipids, small molecules and functional RNAs from the cell of origin. We and others have recently reported on regulatory exosomes from osteoclasts and osteoblasts. Key candidate molecules identified in exosome-based regulation of bone remodelling include receptor activator of nuclear factor kappa B (RANK), RANK-ligand (RANKL), ephrinA2, semaphorin 4D, microRNA-146a and microRNA- 214-3p. Exosomes will likely prove to be crucial elements in the communication networks integrating bone cells (osteoclasts, osteoblasts, osteocytes) and linking bone to other tissue. Exosomes collected from bone cells grown in culture may prove useful to augment bone remodelling associated with orthodontic force application or required for the repair of craniofacial bone. Various technologies allow exosomes to be engineered to improve their targeting and efficacy for therapeutic purposes. In summary, exosomes have emerged as important elements of the machinery for intercellular communication between bone cells. They hold great promise as therapeutic targets, biomarkers and therapeutic agents for orthodontists.

Adjuvant radiotherapy for positive lymph nodes of oesophageal squamous cell carcinoma: Can it earn promising benefits at long-term follow-up?

PURPOSE

The value of adjuvant radiotherapy for patients with positive lymph nodes after curative resection of oesophageal squamous cell carcinoma is controversial. This study aims to investigate its long-term benefits in a specific cohort.

PATIENTS AND METHODS

The charts between 1990 and 2003 from patients with positive lymph nodes were retrospectively reviewed. Those subjects were divided into adjuvant radiotherapy and surgery alone groups, with two subgroups defined by radiation dose (cutoff value: 50Gy). Overall survival, disease-free survival and locoregional recurrence-free survival were compared between two groups, with predictive factors of overall survival analysed meanwhile.

RESULTS

In sum, 175 matched patients with 1:2 ratios for group balance were enrolled for final analysis. During the follow-up (median: 37.0 months), 143 (81.7%) deaths were recorded, with 70.6% of deaths from cancer progression. The median overall survival time (19.5, 4 to 172 months) was not significantly different between the two groups (18.9 vs. 20.0 months, P=0.179). However, the disease-free survival time was significantly shorter in the adjuvant radiotherapy group than that in the control group (median, 11.5 vs. 14.9 months; P=0.001), with the locoregional recurrence-free survival time impressively prolonged (median: 18.3 vs. 16.5 months; P=0.022). Age (P=0.030), number (P=0.005) and ratio (P=0.002) of positive lymph nodes were associated with overall survival, but radiation dose was not (P=0.204).

CONCLUSION

Adjuvant radiotherapy with low- or high-dose did not improve survival compared with surgery alone. However, radiotherapy was effective to control locoregional recurrence, and could be applied as salvage therapy when recurrence event occurred.

[Expressions and clinical significances of paired box gene 2 and cyclin D1 in advanced ovarian serous carcinoma]

Objective: To investigate the expressions and clinical significances of paired box gene 2 (Pax2) and cyclin D1 protein in advanced ovarian serous carcinoma. Methods: From January 2003 to December 2013, the pathologic tissues of 202 patients with advanced ovarian serous cancer (Ⅲ-Ⅳ) who underwent initial cytoreductive surgery were collected. The expressions of Pax2 and cyclin D1 protein were detected by immunohistochemistry in tissue microarray. The relationships of their expressions with the clinicopathological features and prognosis of the patients were analyzed. Results: The positive rate of Pax2 protein expression of the 202 patients with ovarian serous adenocarcinoma was 24.8% (50/202) and that of cyclin D1 was 25.2% (51/202). The expressions of Pax2 and cyclin D1 were not significantly related with age, clinical stage and pathological grade of ovarian serous adenocarcinoma patients (P>0.05). The median overall survival (OS) time of Pax2-negative patients was 53 months and the progression-free survival (PFS) time was 29 months. The median OS time of Pax2-positive patients was 66 months and PFS time was 33 months, the OS of Pax2-negative patients was significant different from that of Pax2-positive patients (χ(2)=4.06, P=0.04). The median PFS time of Pax2-negative patients was not significant different from that of Pax2-positive patients (χ(2)=2.43, P=0.11). The median OS time of cyclin D1-negative patients was 62 months and PFS time was 30 months. The median OS time of cyclin D1-positive patients was 48 months and PFS time was 22 months. The median OS time of cyclin D1-negative patients was significantly different from that of cyclin D1-positive patients (χ(2)=4.71, P=0.03), while the median PFS time of cyclin D1-negative patients was marginally different from that of cyclin D1-positive patients (χ(2)=0.59, P=0.41). Multivariate analysis showed that the expression of Pax2 was an independent factor of the prognosis for patients with ovarian serous adenocarcinoma (RR=0.597, 95% CI 0.371-0.962, P<0.034). Conclusion: The expressions of Pax2 and cyclin D1 are associated with the prognosis of patients with advanced ovarian serous adenocarcinoma while Pax2 is an independent prognostic factor.

The correlation between SNPs within the gene of adrenergic receptor and neuropeptide Y and risk of cervical vertigo

BACKGROUND

The current investigation was aimed to explore the potential associations of SNPs within ADRB2, ADRB1, NPY, and ADRA1A with risk and prognosis of cervical vertigo.

METHODS

Altogether 216 patients with cervical vertigo and 204 healthy controls were gathered, and their DNAs were extracted utilizing the whole-blood DNA extraction kit. Besides, the PCR reactions were conducted using the TaqMan^R single nucleotide polymorphism (SNP) genotyping assays, and the SNPs were detected on the 7900HT real-time fluorogenic quantitative polymerase chain reaction (PCR) instrument. Finally, the severity of cervical vertigo was classified according to the JOA scoring, and the recovery rate (RR) of cervical vertigo was calculated in light of the formula as: [Formula: see text] RESULTS: The SNPs within ADRA1A [rs1048101 (T>C) and rs3802241 (C>T)], NPY [rs16476 (A>C), rs16148 (T>C), and rs5574 (C>T)], ADRB1 [rs28365031 (A>G)] and ADRB2 [rs2053044 (A>G)] were all significantly associated with regulated risk of cervical vertigo (all P < .05). Haplotypes of ADRA1A [CT and TC] and NPY [CCT and ATT] were also suggested as the susceptible factors of cervical vertigo in comparison with other haplotypes. Furthermore, the SNPs within ADRA1A [rs1048101 (T>C)], NPY [rs16476 (A>C), rs16148 (T>C)], as well as ADRB1 [rs28365031 (A>G)] all appeared to predict the prognosis of cervical vertigo in a relatively accurate way (all P < .05). Ultimately, the haplotypes of ADRA1A (CC) and NPY (CCT) tended to decrease the RR.

CONCLUSIONS

The SNPs within ADRB2, ADRB1, NPY, and ADRA1A might act as the diagnostic biomarkers and treatment targets for cervical vertigo.

Oncogenic Ras differentially regulates metabolism and anoikis in extracellular matrix-detached cells

In order for cancer cells to survive during metastasis, they must overcome anoikis, a caspase-dependent cell death process triggered by extracellular matrix (ECM) detachment, and rectify detachment-induced metabolic defects that compromise cell survival. However, the precise signals used by cancer cells to facilitate their survival during metastasis remain poorly understood. We have discovered that oncogenic Ras facilitates the survival of ECM-detached cancer cells by using distinct effector pathways to regulate metabolism and block anoikis. Surprisingly, we find that while Ras-mediated phosphatidylinositol (3)-kinase signaling is critical for rectifying ECM-detachment-induced metabolic deficiencies, the critical downstream effector is serum and glucocorticoid-regulated kinase-1 (SGK-1) rather than Akt. Our data also indicate that oncogenic Ras blocks anoikis by diminishing expression of the phosphatase PHLPP1 (PH Domain and Leucine-Rich Repeat Protein Phosphatase 1), which promotes anoikis through the activation of p38 MAPK. Thus, our study represents a novel paradigm whereby oncogene-initiated signal transduction can promote the survival of ECM-detached cells through divergent downstream effectors.

Characterization of Regulatory Extracellular Vesicles from Osteoclasts

Extracellular vesicles (EVs), which include exosomes and ectosomes/microvesicles, have emerged as important intercellular regulators. EVs can interact with surface receptors of target cells and can transport luminal components, including messenger RNAs (mRNAs), microRNAs, and enzymes, to the cytosol of the target cell. Here, we show that hematopoietic cells grown in culture shed exosome-like EVs as they differentiate from preosteoclasts into osteoclasts. These EVs were between 25 and 120 nm (mean, 40 nm) in diameter determined by transmission electron microscopy. The exosome-associated markers CD63 and EpCAM were enriched in the isolated EVs while markers of Golgi and endoplasmic reticulum were not detected. Treatment of isolated hematopoietic cells with EVs did not affect their receptor activator of nuclear factor κB-ligand (RANKL)-stimulated differentiation into osteoclasts. However, EVs from osteoclast precursors promoted 1,25-dihydroxyvitamin D3-dependent osteoclast formation in whole mouse marrow cultures, and EVs from osteoclast-enriched cultures inhibited osteoclastogenesis in the same cultures. These data suggested that osteoclast-derived EVs are paracrine regulators of osteoclastogenesis. EVs from mature osteoclasts contained receptor activator of nuclear factor κB (RANK). Immunogold labeling showed RANK was enriched in 1 in every 32 EVs isolated from osteoclast-enriched cultures. Depletion of RANK-rich EVs relieved the ability of osteoclast-derived EVs to inhibit osteoclast formation in 1,25-dihydroxyvitamin D3-stimulated marrow cultures. In summary, we show for the first time that EVs released by osteoclasts are novel regulators of osteoclastogenesis. Our data suggest that RANK in EVs may be mechanistically linked to the inhibition of osteoclast formation. RANK present in EVs may function by competitively inhibiting the stimulation of RANK on osteoclast surfaces by RANKL similar to osteoprotegerin. RANK-rich EVs may also take advantage of the RANK/RANKL interaction to target RANK-rich EVs to RANKL-bearing cells for the delivery of other regulatory molecules.

TonEBP modulates the protective effect of taurine in ischemia-induced cytotoxicity in cardiomyocytes

Taurine, which is found at high concentration in the heart, exerts several protective actions on myocardium. Physically, the high level of taurine in heart is maintained by a taurine transporter (TauT), the expression of which is suppressed under ischemic insult. Although taurine supplementation upregulates TauT expression, elevates the intracellular taurine content and ameliorates the ischemic injury of cardiomyocytes (CMs), little is known about the regulatory mechanisms of taurine governing TauT expression under ischemia. In this study, we describe the TonE (tonicity-responsive element)/TonEBP (TonE-binding protein) pathway involved in the taurine-regulated TauT expression in ischemic CMs. Taurine inhibited the ubiquitin-dependent proteasomal degradation of TonEBP, promoted the translocation of TonEBP into the nucleus, enhanced TauT promoter activity and finally upregulated TauT expression in CMs. In addition, we observed that TonEBP had an anti-apoptotic and anti-oxidative role in CMs under ischemia. Moreover, the protective effects of taurine on myocardial ischemia were TonEBP dependent. Collectively, our findings suggest that TonEBP is a core molecule in the protective mechanism of taurine in CMs under ischemic insult.

Characterization of abnormal epithelium after laser-assisted subepithelial keratectomy using in vivo confocal microscopy

This study compared the abnormal corneal epithelium after laser-assisted subepithelial keratectomy (LASEK) with dystrophic cornea using in vivo using confocal microscopy (IVCM) and examined the effects of the abnormal epithelium on postoperative recovery of uncorrected distance visual acuity (UDVA) and sub-basal nerve plexus regeneration. The UDVA and wound healing were examined in 50 eyes of 25 patients undergoing LASEK at 1 week, 1 month, and 1 year postoperatively, including the visual acuity, slit lamp microscopy, and IVCM. After 1 week, the corneal epithelium was healed in all patients, but abnormal epithelial cells were detected in 33/50 patients using IVCM. Abnormal cells were limited to the surgical margin, and highly reflective granules were observed underneath. At 1 month and 1 year postoperatively, the abnormal epithelium was unchanged in size. At 1 year postoperatively, there were clear differences between the sub-basal nerve plexus in the normal and abnormal epithelium. At 1 month postoperatively, the UDVA was >1.0 in 88% of patients, which increased to 94% at 1 year, and there was no clear difference in the UDVA between abnormal (N = 33) and normal (N = 17) epithelium. After LASEK, abnormal epithelial cells may arise at the margin of the epithelial flap and persist 1 year postoperatively accompanied by poor regeneration of the sub-basal nerve plexus. However, this does not affect the UDVA postoperatively. The abnormal epithelium may be caused by residual necrotic basal cell debris on the epithelial basement membrane and abnormal neurotrophic metabolism between the corneal epithelium and nerve plexus.

Immune influence of pregnancy on human H7N9 infection: a case report

INTRODUCTION

H7N9 infection has raised serious concerns worldwide. Pregnant women were considered to be at a high risk of influenza infection. Normal pregnancy was dependent on T helper (Th) 2 deviation. However, whether pregnancy influences the immune status of influenza H7N9 patients has not been reported.

CASE REPORT

Here, we reported a case of pregnant woman in the first trimester with H7N9 infection compared with the two non-pregnant female H7N9 patients for clinical features and relevant immunological changes. We found that there were no differences in plasma levels of Th1 and Th2 cytokines between the pregnant and non-pregnant patients, and there was no Th2 deviation in the acute phase. However, the Th2 deviation was recurrent along with the clearance of infection in the H7N9 pregnant patient.

CONCLUSION

These cases highlighted that the pregnant patient infected with H7N9 could induce an effective Th1 immune response equal to that of non-pregnant patients with H7N9 virus infection, although the pregnancy itself could lead to a Th2 deviation. These data suggested that pregnant patients could acquire a similar antiviral response for H7N9 infection versus non-pregnant patients.

Neural reflex pathway between cervical spinal and sympathetic ganglia in rabbits: implication for pathogenesis of cervical vertigo

BACKGROUND CONTEXT

A functional association between cervix and vertigo has been observed in patients with cervical vertigo, implicating correlation between cervical spinal and sympathetic ganglia. However, it is unclear where there is an anatomic connection between those two groups of ganglia.

PURPOSE

This study aimed to investigate the existence of the neural connections between cervical spinal and sympathetic ganglia.

STUDY DESIGN/SETTING

FluoroGold staining patterns in cervical spinal and sympathetic ganglia were evaluated using FluoroGold retrograde tracing in New Zealand rabbits.

METHODS

New Zealand rabbits were randomly divided into superior cervical spinal ganglion injection groups, inferior cervical spinal ganglion injection groups, superior cervical sympathetic ganglion injection group, and inferior cervical sympathetic ganglion injection group. Four percent FluoroGold solution was injected into these ganglia. Distribution of FluoroGold in cervical spinal and sympathetic ganglia was observed under a microscope.

RESULTS

When FluoroGold solution was injected into C2 and C3 superior cervical spinal ganglia or C5-C6 inferior cervical spinal ganglia, fluorescence was only observed in the ipsilateral superior or inferior cervical sympathetic ganglia, respectively. When FluoroGold solution was injected into superior or inferior cervical sympathetic ganglia, fluorescence was found mainly in the ipsilateral C3-C4 superior or C5-C8 inferior spinal ganglia. No fluorescence was observed in contralateral ganglia of experimental animals and all ganglia of matched control animals injected with physiological saline.

CONCLUSIONS

Bidirectional nerve fiber connections between cervical spinal and sympathetic ganglia were observed, and these connections are arranged in a segmental distribution. This observation may provide a possible neuroanatomic basis for the pathogenesis of cervical vertigo.

Bis-enoxacin inhibits bone resorption and orthodontic tooth movement

Enoxacin inhibits binding between the B-subunit of vacuolar H(+)-ATPase (V-ATPase) and microfilaments, and also between osteoclast formation and bone resorption in vitro. We hypothesized that a bisphosphonate derivative of enoxacin, bis-enoxacin (BE), which was previously studied as a bone-directed antibiotic, might have similar activities. BE shared a number of characteristics with enoxacin: It blocked binding between the recombinant B-subunit and microfilaments and inhibited osteoclastogenesis in cell culture with IC50s of about 10 µM in each case. BE did not alter the relative expression levels of various osteoclast-specific proteins. Even though tartrate-resistant acid phosphatase 5b was expressed, proteolytic activation of the latent pro-enzyme was inhibited. However, unlike enoxacin, BE stimulated caspase-3 activity. BE bound to bone slices and inhibited bone resorption by osteoclasts on BE-coated bone slices in cell culture. BE reduced the amount of orthodontic tooth movement achieved in rats after 28 days. Analysis of these data suggests that BE is a novel anti-resorptive molecule that is active both in vitro and in vivo and may have clinical uses.

ABBREVIATIONS

BE, bis-enoxacin; V-ATPase, vacuolar H(+)-ATPase; TRAP, tartrate-resistant acid phosphatase; αMEM D10, minimal essential media, alpha modification with 10% fetal bovine serum; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; RANKL, receptor activator of nuclear factor kappa B-ligand; NFATc1, nuclear factor of activated T-cells; ADAM, a disintegrin and metalloprotease domain; OTM, orthodontic tooth movement.

Genetic polymorphisms of drug-metabolizing phase I enzymes CYP3A4, CYP2C9, CYP2C19 and CYP2D6 in Han, Uighur, Hui and Mongolian Chinese populations

We randomly evaluated 672 unrelated, healthy Chinese volunteers (136 Han, 214 Uighur, 164 Hui and 158 Mongolian) to compare CYP3A4, CYP2C9, CYP2C19 and CYP2D6 allele frequencies. Genomic DNA was extracted from peripheral leukocytes and genotyped for CYP3A4*5, CYP3A4*18, CYP2C9*2, CYP2C9*13, CYP2C19*2, CYP2C19*3 and CYP2D6*10 by PCR-restriction fragment length polymorphism analysis (PCR-RFLP). Our results showed that there is no significant difference in the distribution of CYP2C19*3 and CYP3A4*18 genotypes in the Han, Uighur, Hui and Mongolian Chinese populations. The CYP2C9*13/*13 and CYP3A4*5 genotypes were not observed in any of the four Chinese populations. We found a higher incidence of the CYP2C9*2 allele in Uighur populations, compared to the Han, Hui and Mongolian populations. The incidence of the CYP2C19*2 allele in the Han population was not significantly different from that in the Uighur, Hui or Mongolian populations; however, the Uighur population showed significantly lower rates of this allele than the Hui and Mongolian populations, and the Mongolian population had a significantly lower incidence of this allele than the Hui population. There was no significant difference in the presence of the CYP2D6*10 allele in the Mongolian, Han or Hui populations. However, the Uighur population showed significantly lower rates of this allele than the other three populations. These findings provide basic genetic information for further pharmacogenomic investigations in the Chinese population.

Comparison of adsorption of mercaptopropyltrimethoxysilane on amphiphilic TiO2 and hydroxylated SiO2

Alkylsilane 3-mercaptopropyltrimethoxysilane (3MPT) monolayers with a functional end group -SH were used to immobilize Ag colloidal nanoparticles on photoinduced amphiphilic TiO(2) and hydroxylated SiO(2) surfaces. The differences in the adsorption of 3MPT and the immobilization of Ag colloids on both surfaces were studied. Under identical experimental conditions, 3MPT islands were formed on UV-exposed TiO(2) surfaces compared to continuous and flat monolayers formed on SiO(2). The significant structural differences found for monolayers of 3MPT on TiO(2) could be explained in terms of the different densities of hydroxyl groups and the microstructure of hydrophilic domains induced by UV irradiation. The surface properties were characterized using contact angle measurements and XPS. XPS showed an increase in the hydroxyl group's density and a decrease in the number of adsorbed hydrocarbon films on the TiO(2) surface as a function of the UV irradiation time. The density of the adsorbed 3MPT on TiO(2) surfaces as a function of the UV irradiation time was quantitatively related to the cosine of the water contact angles. Such a 3MPT distribution influenced the subsequent adsorption of Ag colloids and resulted in more isolated nanoparticles on the modified TiO(2) with a narrower size distribution.

A micro creeping robot for colonoscopy based on the earthworm

Minimally Invasive Surgery (MIS) has become one of the most important research areas in the field of medical engineering. Robotic colonoscopy is a typical medical procedure that complies with the requirements of MIS. In this paper, a new novel miniature robot for intestinal inspection based on the earthworm is described; its diameter and length are 7.5 mm and 120 mm respectively. The micro robot is driven by a DC motor which has good performance and sufficient power. In this paper the structure and locomotion mechanism of this robot are introduced; the mechanical model is built; and simulation is carried out. The control system and software design are also discussed in detail. Some actuating characteristic experiments have been performed, where the micro robot creeps in declining rubber tubes. The experimental results are in accord with simulation results, and show that this kind of robot can move reliably in horizontal and certain declining tubes. This research has laid a foundation for the application of the miniature robot endoscope.

Collapse and stability of single- and multi-wall carbon nanotubes

The collapse and stability of carbon nanotubes (CNTs) have important implications for their synthesis and applications. While nanotube collapse has been observed experimentally, the conditions for the collapse, especially its dependence on tube structures, are not clear. We have studied the energetics of the collapse of single- and multi-wall CNTs via atomistic simulations. The collapse is governed by the number of walls and the radius of the inner-most wall. The collapsed structure is energetically favored about a certain diameter, which is 4.12, 4.96 and 5.76 nm for single-, double- and triple-wall CNTs, respectively. The CNT chirality also has a strong influence on the collapsed structure, leading to flat, warped and twisted CNTs, depending on the chiral angle.