Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15  PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10  TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60  TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory of the bright GRB 221009A, which serendipitously occurred within the instrument field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger, then rose to a peak about 10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

[Biomechanical study of anterior occipital condyle screw plate system]

Objective: To analyze the feasibility of anterior occipitocervical fusion biomechanical characteristic of craniovertebral reconstruction by anterior occipital condyle screw plate system. Methods: Six cervical vertebra specimens including 4 males and 2 females were enrolled, whose mean age of death was (49.3±7.5) years. The normal models were established by soft tissue dissection, and the instability models were established by destroy bone and ligament structure including, anterior arch of the atlas, part of the lateral mass of the atlas, the odontoid process, the odontoid apical ligament, the pterygoid ligament, the transverse ligament of the atlas the joint capsule. The clivus screw fixation models were established by anterior clivus screw fixation, and then those models were performed by anterior occipital condyle screw fixation. All four groups were loaded with a 1.5 N·m continuous pure force in flexion-extension, lateral bending, and axial rotation. Then measured the range of motion of specimen C₀-C₁ and C₀-C₂. And the pull-out force test was conducted to compare the effects of unicortical and bicortical fixation on the pull-out force of screws. Results: In the C₀-C₁ segment, the range of motion in flexion-extension (forward and posterior), lateral bending and axial rotation in the clivus group was 6.46°±0.85°, 5.14°±0.76°, 2.73°±0.36°, 1.12°±0.41°, respectively; and it was 5.92°±0.90°, 4.16°±1.06°, 2.86°±0.50°, 1.05°±0.27°, respectively in the occipital condyle group. As for C₀-C₂ segment, the range of motion in the clivus group was 9.55°±1.99°, 10.46°±2.03°, 6.90°±1.29°, 13.51°±1.37°, respectively; and it was 8.14°±1.38°, 9.53°±1.55°, 4.75°±1.06°, 7.90°±1.68°, respectively, in the occipital condyle group. The ranges of motion in the occipital condyle group were significantly lower than clivus group (all P<0.05). The maximum pull out force by bicortical fixation was significantly better than unicortical fixation ((439±33) N vs (408±28) N, P<0.05). Conclusion: The anterior occipital condyle screw plate system provides better stability especially in anti-bending and anti-rotation than the anterior clival screw fixation.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Environmental tobacco smoke and cancer risk, a prospective cohort study in a Chinese population

Few prospective cohort studies have investigated associations between environmental tobacco smoke (ETS) and other cancer sites, in addition to lung cancer. We assessed these associations in a population-based prospective cohort study started from 2008 to 2011 with average of 9.1 years of follow-up, in Minhang district, Shanghai, China. The study included a total of 23,415 participants (8388 men, 15,027 women) and 205,515 person-years. Epidemiological data were collected by a standardized questionnaire including ETS exposure. Newly diagnosed patients with primary cancers and deaths were identified by record linkage system with the Shanghai Cancer Registry and Shanghai Vital Statistics. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression models, adjusting for potential confounders. During the study period, a total of 1462 patients with diagnoses of primary cancers were identified. Among all participants and non-smokers, ETS was associated with an increased risk of all smoking-related cancers (all: adjusted HR: 1.23, 95% CI: 1.05-1.43 and non-smokers: 1.24, 1.02-1.49), lung cancer (1.29, 0.98-1.71 and 1.27, 0.91-1.77), and stomach cancer (1.86, 1.21-2.85 and 1.75, 1.05-2.91), respectively. Furthermore, associations for lung and stomach cancers were the strongest among non-smoking females. The joint effects of both ETS and active smoking were strongest for all cancers, all smoking-related cancers, lung cancer, and stomach cancer. No clear interactions were observed. These results suggest that ETS exposure may increase the risk of smoking-related cancers in a Chinese population. Further studies on the relationship between ETS exposure and specific cancer sites are warranted to replicate our findings.

Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100  TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100  TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100  TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

[Screening and bioinformatic analysis of trehalase in Thelazia callipaeda]

OBJECTIVE

To characterize the trehalase gene in Thelazia callipaeda through screening the annotated data of the T. callipaeda genome, and to investigate the biological characteristics of the trehalase gene-coding protein.

METHODS

The trehalase gene was screened from the T. callipaeda genome and subjected to validation by using a PCR assay. The structural features of the coding protein were analyzed with bioinformatics tools, including hydrophobicity, transmembrane region, signal peptides, conserved domains, as well as the secondary and tertiary structures and the antigen epitope. Homology analysis of the amino acid sequences was performed, and the phylogenetic tree was built by the MEGA X software. In addition, the protein-protein interaction network was deduced from the STRING database.

RESULTS

The sequence of the trehalase gene with the complete CDS region was obtained from T. callipaeda genome, which had a length of 1 638 bp and encoded 545 amino acids. The encoded protein was predicted to have a molecular weight of 63 478.48 ku and be a secretory protein. The 5' domain of the encoded protein contained a signal peptide without transmembrane regions, and was predicted to contain 7 antigen epitopes. Based on the protein-protein interaction network of nematodes in the STRING database, the protein-protein interaction network of the trehalase gene of T. callipaeda was deduced, and 27 interactions covering 10 genes were identified.

CONCLUSIONS

A trehalase gene is successfully identified in T. callipaeda genome and its coding protein receives a bioinformatics analysis, which provides insights into the research on the biological functions of the protein and the screening of vaccine candidates for thelaziasis callipaeda.

Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

[Prognostic value of N-terminal B-type natriuretic peptide on all-cause mortality in heart failure patients with preserved ejection fraction]

Objective: To investigate the prognostic value of N-terminal B-type natriuretic peptide (NT-proBNP) on all-cause mortality in heart failure patients with preserved ejection fraction (HFpEF) at real world scenarios. Methods: Patients who met the diagnostic criteria of HFpEF in the China National Heart Failure Registration Study (CN-HF) were divided into death and survival groups. The demographic data, physical examination, results of the first echocardiography, laboratory results at admission, complications, drug use and clinical outcomes were obtained from CN-HF. The univariate Cox proportional hazard model was used to screen the variates that might predict prognosis, and then the covariates with statistical significance were included in the multivariate Cox regression model to analyze the predictive value of baseline NT-proBNP on all-cause death. Spearman correlation analysis was used to evaluate the relationship between NT-proBNP and estimated glomerular filtration rate (eGFR), so as to further explore the predictive value of the interaction between renal dysfunction and NT-proBNP on death. Since NT-proBNP did not obey the binary normal distribution, it was expressed by the natural logarithm of NT-proBNP (LnNT-proBNP). Results: A total of 1 846 HFpEF patients were enrolled in this study, with an average age of 71.5 years, 1 017 males(55.1%), median NT-proBNP 860 ng/L, and median eGFR 73.9 ml·min^-1·1.73m^-2. After a median follow-up of 34 months, 213 (11.5%) patients died. Patients in the death group were older, with higher NYHA classification Ⅲ-Ⅳ ratio, longer hospital stay, higher serum potassium and NT-proBNP level, prevalence of complications of diabetes mellitus, arrhythmia and atrial fibrillation, use of angiotensin receptor antagonist(ARB), mineralocorticoid receptor antagonists (MRA), diuretic and digoxin was significantly higher in death group than in survival group. Body mass index (BMI), diastolic blood pressure, left ventricular ejection fraction (LVEF), hemoglobin, serum cholesterol(TC), serum triglycerides (TG) and eGFR, and use of angiotensin converting enzyme inhibitors (ACEI), statins and aspirin were lower in death group than in survival group. Univariate Cox regression analysis showed that NT-proBNP was a predictor of all-cause death in HFpEF patients (HR=2.522, 95%CI 2.040-3.119, P<0.001). Multivariate Cox regression analysis showed that the elevated NT-proBNP remains as the independent predictor of all-cause death in patients with HFpEF (HR=1.230, 95%CI 1.049-1.442, P=0.011) after adjusting for age, BMI, diastolic blood pressure, LVEF, hemoglobin, serum potassium, serum sodium, TC, serum high-density lipoprotein cholesterol (HDL-C), TG, eGFR, atrial fibrillation, as well as the treatment of ACEI/ARB, MRA, diuretics and digoxin. Spearman correlation analysis showed that LnNT-proBNP was negatively correlated with eGFR (r=-0.361, P<0.001), but there was no interaction between NT-proBNP and renal dysfunction in predicting death in HFpEF patients (P>0.05). Conclusion: The elevated level of NT-proBNP at admission is an independent predictor of all-cause mortality in HFpEF patients.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Strategic Design of Vacancy-Enriched Fe1- xS Nanoparticles Anchored on Fe3C-Encapsulated and N-Doped Carbon Nanotube Hybrids for High-Efficiency Triiodide Reduction in Dye-Sensitized Solar Cells

A new class of hybrids with the unique electrocatalytic nanoarchitecture of Fe_{1- x}S anchored on Fe₃C-encapsulated and N-doped carbon nanotubes (Fe_{1- x}S/Fe₃C-NCNTs) is innovatively synthesized through a facile one-step carbonization-sulfurization strategy. The efficient synthetic protocols on phase structure evolution and dynamic decomposition behavior enable the production of the Fe_{1- x}S/Fe₃C-NCNT hybrid with advanced structural and electronic properties, in which the Fe vacancy-contained Fe_{1- x}S showed the 3d metallic state electrons and an electroactive Fe in +2/+3 valence, and the electronic structure of the CNT was effectively modulated by the incorporated Fe₃C and N, with the work function decreased from 4.85 to 4.63 eV. The meticulous structural, electronic, and compositional control unveils the unusual synergetic catalytic properties for the Fe_{1- x}S/Fe₃C-NCNT hybrid when developed as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), in which the Fe₃C- and N-incorporated CNTs with reduced work function and increased charge density provide a highway for electron transport and facilitate the electron migration from Fe₃C-NCNTs to ultrahigh active Fe_{1- x}S with the electron-donating effect, and the Fe vacancy-enriched Fe_{1- x}S nanoparticles exhibit ultrahigh I₃^- adsorption and charge-transfer ability. As a consequence, the DSSC based on the Fe_{1- x}S/Fe₃C-NCNT CE delivers a high power conversion efficiency of 8.67% and good long-term stability with a remnant efficiency of 8.00% after 168 h of illumination, superior to those of traditional Pt. Furthermore, the possible catalytic mechanism toward I₃^- reduction is creatively proposed based on the structure-activity correlation. In this work, the structure engineering, electronic modulation, and composition control opens up new possibilities in constructing the novel electrocatalytic nanoarchitecture for highly efficient CEs in DSSCs.

Body mass index and cancer risk among Chinese patients with type 2 diabetes mellitus

Background

Obesity and diabetes are two risk factors for cancer. To evaluate the association of body mass index (BMI) with cancer risk in diabetic patients may improve current understanding of potential mechanisms.

Methods

A retrospective cohort study was conducted in 51,004 newly diagnosed T2DM patients derived from an electronic health record (EHR) database of Minhang district in Shanghai, China. Incident cancer cases and all-cause deaths occurred before September 30, 2015 were identified by linking with the Shanghai Cancer Registry and the Shanghai Vital Statistics. To examine the potential non-linear and linear relationships of BMI and cancer risk, Cox proportional hazard models with and without restricted cubic spline functions were used, respectively.

Results

A non-linear association was observed between BMI and overall cancer incidence in men younger than 60 years old (p for non-linearity = 0.009). Compared with those having BMI of 25.0 kg/m², the cancer risk increased in those with either lower or higher BMI. In women older than 60 years old, linear dose-response relationships were observed between BMI and the risk of both overall cancer and breast cancer. As each unit increase in BMI, the overall cancer risks elevated by 3% (95%CI: 1–5%) and the breast cancer risks increased by 7% (95%CI: 1–13%). No significant association was observed between BMI and other common cancer sites.

Conclusions

Our results show that the effect of BMI on cancer risk in Chinese patients with T2DM may vary by gender, age and cancer subtypes, suggesting different underlying biological mechanisms.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4675-0) contains supplementary material, which is available to authorized users.

[Feasibility of screw placement on posterior occipital condyle assisted by occipital tangent angulation]

Objective: To investigate the practicability of occipital tangent angle in assisting posterior occipital condylar screw placement and to verify the safety and accuracy of self-made screw placement device for auxiliary screw. Methods: Occipito-cervical region specimens of 12 adult corpses were selected and scanned by thin-cut CT examination.The three-dimensional reconstruction of occipital and atlas was simulated for each specimen, and 3-matic software was used to measure the setting parameters, including occipital tangent angle, head obliquity, internal inclination angle, length of the screw and the distance from the inferior margin of hypoglossal canal to the screw axis.Using the self-designed occipital condylar screw placement device, combined with occipital tangent angle, internal inclination angle and insertion point, the posterior occipital condylar screw specimen was inserted with nails with assisting tool.The occipito-cervical region was reconstructed and scanned by thin-cut CT examination again after the operation to measuring the parameters of screw placement after actual screwing.The paired t test was used to compare the parameters of screw placement before and after operation. Results: Pre-operative three dimensional reconstruction of occipital condyle screw showed that the head obliquity was 5.3°±0.9°, the tangent angle was 14.9°±3.7°, the internal inclination angle was 28.1°±5.9°, and the length of screw insertion was (21.4±1.7) mm respectively; the distance from the inferior margin of hypoglossal canal to the screw axis was (4.74±0.36) mm.There was no significant difference in the parameters of analogue nailing between the left and right occipital condyles before the operation (t=-1.32, -0.48, 0.10, 0.23, 0.09, all P>0.05). The occipital condylar screw was safely implanted with screw placement device.The screw was located in the ideal nail insertion channel after operation by CT scan evaluation, without any injury to the hypoglossal canal, the atlanto-occipital articular surface and other structure.After the operation, the actual nailing parameters were measured: the head inclination angle was 5.2°±0.7°, the tangent angle was 15.1°±3.2°, the internal inclination angle was 28.2°±4.2°, the length of screw insertion was (21.5±1.7) mm, the distance from the inferior margin of hypoglossal canal to the screw axis was (4.54±0.29) mm.There was no significant difference between the left and right side in the actual screw placement parameters (t=-0.77, 0.82, 0.56, 0.22, 0.21, all P>0.05). It was found that there was no significant differences in the head obliquity, the occipital tangent angle, the internal inclination angle, length of screw entry, and the distance from the inferior margin of hypoglossal canal to the screw axis before and after the operation (t=0.56, -0.47, -0.18, -0.70, 1.89, all P>0.05). Conclusion: The occipital tangent angle can be measured directly in the process of posterior occipital condyle screw insertion to guide occipital condylar screw insertion, and the self-made occipital condylar screw placement device can effectively combine the three parameters: occipital tangent angle, head inclination angle and insertion point, which can improve the safety of posterior occipital condylar screw insertion.

[Identification and drug susceptibility testing of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis]

Objective: To understand the etiological characteristics and drug susceptibility of Mycobacterium thermoresistibile and Mycobacterium elephantis isolated from a cow with mastitis and provide evidence for the prevention and control of infectious mastitis in cows. Methods: The milk sample was collected from a cow with mastitis, which was pretreated with 4% NaOH and inoculated with L-J medium for Mycobacterium isolation. The positive cultures were initially identified by acid-fast staining and multi-loci PCR, then Mycobacterium species was identified by the multiple loci sequence analysis (MLSA) with 16S rRNA, hsp65, ITS and SodA genes. The drug sensitivity of the isolates to 27 antibiotics was tested by alamar blue assay. Results: Two anti-acid stain positive strains were isolated from the milk of a cow with mastitis, which were identified as non-tuberculosis mycobacterium by multi-loci PCR, and multi-loci nucleic acid sequence analysis indicated that one strain was Mycobacterium thermoresistibile and another one was Mycobacterium elephantis. The results of the drug susceptibility test showed that the two strains were resistant to most antibiotics, including rifampicin and isoniazid, but they were sensitive to amikacin, moxifloxacin, levofloxacin, ethambutol, streptomycin, tobramycin, ciprofloxacin and linezolid. Conclusions:Mycobacterium thermoresistibile and Mycobacterium elephantis were isolated in a cow with mastitis and the drug susceptibility spectrum of the pathogens were unique. The results of the study can be used as reference for the prevention and control the infection in cows.

[Classification of the anatomical structures of maxillary central incisor root by cone-beam CT]

Objective: To examine the root position of the maxillary central incisors and to provide clinical reference before the immediate implant placement. Methods: Cone-beam CT (CBCT) data of the maxillary central incisors of 934 patients (934 incisors) was selected and the root position classsified. The sagittal root position in the alveolar bone was classified as buccal, middle, or palatal. The buccally positoined type was further classified into three subtypes of Ⅰ,Ⅱ, and Ⅲ. Results: Most of the maxillary incisor root (95.4% [891/934]) was positioned buccally. Among the buccal-type incisors, the subtypes Ⅰ, Ⅱ and Ⅲ accounted for 47.5% (423/891), 44.2% (394/891), and 8.3% (74/891). In the 4 mm apical to the cemento-enamel junction and the middle of the root, the thickest buccal bone wall was 0.86 and 0.95 mm, the thickest palatal bone wall was 1.65 and 2.37 mm. In the apical location, the thickest buccal bone wall was 1.89 mm, the thickest palatal bone wall was 7.83 mm. Conclusions: Most of the maxillary central incisors studied are positioned buccally, and half of these patients have adequate buccal bone and are suitable for immediate implant placement.

[A retrospective analysis of clinical characteristics and outcomes of heart failure patients with different left ventricular ejection fractions]

Objective: To compare the clinical characteristics, and outcomes of patients with heart failure with different left ventricular ejection fractions (LVEF). Methods: A total of 1 182 hospitalized patients with heart failure (HF) were enrolled and retrospectively studied in the present study. The patients were stratified by LVEF as reduced (HFrEF, LVEF<40%, n=313), mid-range (HFmrEF, 40% ≤LVEF <50%, n=287) and preserved (HFpEF, LVEF≥50%, n=582) ejection fraction groups. Among the 1 182 cases, 941 of them (81.3%, 84.9%, and 84.0% inHFrEF, HFmrEF and HFpEF groups, respectively) were followed up for an median duration of 27.3 months. Results: (1) Among the study patients, 26.5% were in HFrEF, 24.3% in HFmrEF, and 49.2% in HFpEF groups. (2) Ischemic heart disease with HFmrEF was more frequent than that in patients with HFrEF. The average age, percentage of female subjects, systolic blood pressure, uric acid, N terminal B-type natriuretic peptide precursor (NT-proBNP), hemoglobin, and the incidence of hypertensive heart disease, anemia, atrial fibrillation in patients with HFmrEF were higher than those in patients with HFrEF, but lower than those in patients with HFpEF (all P<0.01). (3) The all-cause cumulative mortality was 10.8% at 1 year, 20.6% at 2 years and 35.9% at 5 years. No difference was observed in the all-cause cumulative mortality at 1 year, 2 years, 5 years among the three groups (all P>0.05). Conclusions: The HFmrEF patients, as a new and distinct group, were with many intermediate characteristics compared with HFrEF and HFpEF subjects. However, the all-cause mortality was not significantly different among HF patients with different LVEF.

Constraints on Ultrahigh-Energy Cosmic-Ray Sources from a Search for Neutrinos above 10 PeV with IceCube

We report constraints on the sources of ultrahigh-energy cosmic rays (UHECRs) above 10^{9}  GeV, based on an analysis of seven years of IceCube data. This analysis efficiently selects very high- energy neutrino-induced events which have deposited energies from 5×10^{5}  GeV to above 10^{11}  GeV. Two neutrino-induced events with an estimated deposited energy of (2.6±0.3)×10^{6}  GeV, the highest neutrino energy observed so far, and (7.7±2.0)×10^{5}  GeV were detected. The atmospheric background-only hypothesis of detecting these events is rejected at 3.6σ. The hypothesis that the observed events are of cosmogenic origin is also rejected at >99% CL because of the limited deposited energy and the nonobservation of events at higher energy, while their observation is consistent with an astrophysical origin. Our limits on cosmogenic neutrino fluxes disfavor the UHECR sources having a cosmological evolution stronger than the star formation rate, e.g., active galactic nuclei and γ-ray bursts, assuming proton-dominated UHECRs. Constraints on UHECR sources including mixed and heavy UHECR compositions are obtained for models of neutrino production within UHECR sources. Our limit disfavors a significant part of parameter space for active galactic nuclei and new-born pulsar models. These limits on the ultrahigh-energy neutrino flux models are the most stringent to date.

Construction of Highly Catalytic Porous TiOPC Nanocomposite Counter Electrodes for Dye-Sensitized Solar Cells

Developing low-cost, durable, and highly catalytic counter electrode (CE) materials based on earth-abundant elements is essential for dye-sensitized solar cells (DSSCs). In this study, we report a highly active nanostructured compositional material, TiOPC, which contains titanium, oxygen, phosphorus, and carbon, for efficient CE in I₃^-/I^- electrolyte. The TiOPC nanocomposites are prepared from carbon thermal transformation of TiP₂O₇ in an atmosphere of nitrogen at high temperature, and their catalytic performance is regulated by changing the carbon content in the nanocomposites. The TiOPC with appropriate 24.6 wt % carbon and porous structure exhibits an enhanced electrocatalytic activity in the reduction of I₃^-, providing a short-circuit current density of 16.64 mA cm^-2, an open-circuit potential of 0.78 V, and an energy conversion efficiency of 8.65%. The photovoltaic performance of TiOPC CE-based DSSC is even superior to that of a Pt CE-based cell (13.80 mA cm^-2, 0.79 V, and 6.66%). The enhanced catalytic activity of TiOPC is attributed to the presence of predominant Ti-O-P-C structure along with the continuous conductive carbon network and the porous structure.

Searches for Sterile Neutrinos with the IceCube Detector

The IceCube neutrino telescope at the South Pole has measured the atmospheric muon neutrino spectrum as a function of zenith angle and energy in the approximate 320 GeV to 20 TeV range, to search for the oscillation signatures of light sterile neutrinos. No evidence for anomalous ν_{μ} or ν[over ¯]_{μ} disappearance is observed in either of two independently developed analyses, each using one year of atmospheric neutrino data. New exclusion limits are placed on the parameter space of the 3+1 model, in which muon antineutrinos experience a strong Mikheyev-Smirnov-Wolfenstein-resonant oscillation. The exclusion limits extend to sin^{2}2θ_{24}≤0.02 at Δm^{2}∼0.3  eV^{2} at the 90% confidence level. The allowed region from global analysis of appearance experiments, including LSND and MiniBooNE, is excluded at approximately the 99% confidence level for the global best-fit value of |U_{e4}|^{2}.

Identification and evaluation of reference genes in the Chinese white wax scale insect Ericerus pela

BACKGROUND

The Chinese white wax scale insect, Ericerus pela, is a well-known resource insect. The females and males are dramatically distinct at each developmental stage. We sought to identify suitable reference genes to use as internal controls in molecular research on E. plea.

RESULTS

geNorm, RefFinder and Normfinder analyses showed that ßTub-2 was the best reference gene throughout different developmental stages; SdhA-1 was the most stable reference gene in different tissues, and ßTub-1 was the most reliable reference gene under treatment with different temperatures. The results also showed that the optimal number of reference genes for analyzing target gene expression levels in the three experimental conditions was two.

CONCLUSIONS

The identified reference genes are suitable reference genes for normalization in RT-qPCR of E. pela samples.

Evidence for Astrophysical Muon Neutrinos from the Northern Sky with IceCube

Results from the IceCube Neutrino Observatory have recently provided compelling evidence for the existence of a high energy astrophysical neutrino flux utilizing a dominantly Southern Hemisphere data set consisting primarily of ν(e) and ν(τ) charged-current and neutral-current (cascade) neutrino interactions. In the analysis presented here, a data sample of approximately 35,000 muon neutrinos from the Northern sky is extracted from data taken during 659.5 days of live time recorded between May 2010 and May 2012. While this sample is composed primarily of neutrinos produced by cosmic ray interactions in Earth's atmosphere, the highest energy events are inconsistent with a hypothesis of solely terrestrial origin at 3.7σ significance. These neutrinos can, however, be explained by an astrophysical flux per neutrino flavor at a level of Φ(E(ν))=9.9(-3.4)(+3.9)×10(-19)  GeV(-1) cm(-2) sr(-1) s(-1)(E(ν)/100  TeV(-2), consistent with IceCube's Southern-Hemisphere-dominated result. Additionally, a fit for an astrophysical flux with an arbitrary spectral index is performed. We find a spectral index of 2.2(-0.2)(+0.2), which is also in good agreement with the Southern Hemisphere result.

Pathway-based network analysis of myeloma tumors: monoclonal gammopathy of unknown significance, smoldering multiple myeloma, and multiple myeloma

Although many studies have been carried out on monoclonal gammopathy of unknown significances (MGUS), smoldering multiple myeloma (SMM), and multiple myeloma (MM), their classification and underlying pathogenesis are far from elucidated. To discover the relationships among MGUS, SMM, and MM at the transcriptome level, differentially expressed genes in MGUS, SMM, and MM were identified by the rank product method, and then co-expression networks were constructed by integrating the data. Finally, a pathway-network was constructed based on Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and the relationships between the pathways were identified. The results indicated that there were 55, 78, and 138 pathways involved in the myeloma tumor developmental stages of MGUS, SMM, and MM, respectively. The biological processes identified therein were found to have a close relationship with the immune system. Processes and pathways related to the abnormal activity of DNA and RNA were also present in SMM and MM. Six common pathways were found in the whole process of myeloma tumor development. Nine pathways were shown to participate in the progression of MGUS to SMM, and prostate cancer was the sole pathway that was involved only in MGUS and MM. Pathway-network analysis might provide a new indicator for the developmental stage diagnosis of myeloma tumors.

Flavor Ratio of Astrophysical Neutrinos above 35 TeV in IceCube

A diffuse flux of astrophysical neutrinos above 100 TeV has been observed at the IceCube Neutrino Observatory. Here we extend this analysis to probe the astrophysical flux down to 35 TeV and analyze its flavor composition by classifying events as showers or tracks. Taking advantage of lower atmospheric backgrounds for showerlike events, we obtain a shower-biased sample containing 129 showers and 8 tracks collected in three years from 2010 to 2013. We demonstrate consistency with the (fe:fμ:fτ)⊕≈(1:1:1)⊕ flavor ratio at Earth commonly expected from the averaged oscillations of neutrinos produced by pion decay in distant astrophysical sources. Limits are placed on nonstandard flavor compositions that cannot be produced by averaged neutrino oscillations but could arise in exotic physics scenarios. A maximally tracklike composition of (0:1:0)⊕ is excluded at 3.3σ, and a purely showerlike composition of (1:0:0)⊕ is excluded at 2.3σ.

Cloning and expression analysis of four heat shock protein genes in Ericerus pela (Homoptera: Coccidae)

To explore the function of small heat shock protein genes (shsps) and hsp70 in Ericerus pela, we cloned the full-length cDNA sequences of hsp21.5, hsp21.7, hsp70, and hsc70 and the genomic sequence of hsc70. Open reading frames of the four hsps were 570, 564, 1,908, and 1,962 base pairs (bp), respectively, which encode proteins with calculated molecular mass of 21.5, 21.7, 69.8, and 71.6 kDa. Amino acid sequence analysis revealed the presence of the conserved Hsp motifs in all four proteins. The genomic DNA of hsc70 had four introns. ep-hsp21.5 was orthologous and ep-hsp21.7 was species specific. Expression of all four transcripts during heat or cold stress and development was examined by quantitative real-time polymerase chain reaction. All four hsps were upregulated during heat or cold stress in female adults, indicating a correlation between the four hsps and heat or cold-stress tolerance in female adults. ep-hsp21.7 and ep-hsp70 were upregulated during heat stress in male larvae, implying a correlation between the two hsps and heat-stress tolerance in male larvae. The four ep-hsps were also upregulated during the developmental process in males, and ep-hsp21.5, ep-hsp70, and ep-hsc70 were upregulated in females, which indicates their possible role in the developmental regulation of E. pela.

Observation of high-energy astrophysical neutrinos in three years of IceCube data

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8)  GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

Complete mitochondrial genome sequences of two parasitic/commensal nemerteans, Gononemertes parasita and Nemertopsis tetraclitophila (Nemertea: Hoplonemertea)

BACKGROUND

Most nemerteans (phylum Nemertea) are free-living, but about 50 species are known to be firmly associated with other marine invertebrates. For example, Gononemertes parasita is associated with ascidians, and Nemertopsis tetraclitophila with barnacles. There are 12 complete or near-complete mitochondrial genome (mitogenome) sequences of nemerteans available in GenBank, but no mitogenomes of none free-living nemerteans have been determined so far. In the present paper complete mitogenomes of the above two parasitic/commensal nemerteans are reported.

METHODS

The complete mitochondrial genomes (mitogenome) of G. parasita and N. tetraclitophila were amplified by conventional and long PCR. Phylogenetic analyses of maximum likelihood (ML) and Bayesian inference (BI) were performed with both concatenated nucleotide and amino acid sequences.

RESULTS

Complete mitogenomes of G. parasita and N. tetraclitophila are 14742 bp and 14597 bp in size, respectively, which are within the range of published Hoplonemertea mitogenomes. Their gene orders are identical to that of published Hoplonemertea mitogenomes, but different from those of Palaeo- and Heteronemertea species. All the coding genes, as well as major non-coding regions (mNCRs), are AT rich, which is especially pronounced at the third codon position. The AT/GC skew pattern of the coding strand is the same among nemertean mitogenomes, but is variable in the mNCRs. Some slight differences are found between mitogenomes of the present species and other hoplonemerteans: in G. parasita the mNCR is biased toward T and C (contrary to other hoplonemerteans) and the rrnS gene has a unique 58-bp insertion at the 5' end; in N. tetraclitophila the nad3 gene starts with the ATT codon (ATG in other hoplonemerteans). Phylogenetic analyses of the nucleotide and amino acid datasets show early divergent positions of G. parasita and N. tetraclitophila within the analyzed Distromatonemertea species, and provide strong support for the close relationship between Hoplonemertea and Heteronemertea.

CONCLUSION

Gene order is highly conserved within the order Monostilifera, particularly within the Distromatonemertea, and the special lifestyle of G. parasita and N. tetraclitophila does not bring significant variations to the overall structures of their mitogenomes in comparison with free-living hoplonemerteans.

Analytical criterion for amplitude death in nonautonomous systems with piecewise nonlinear coupling

We investigate the amplitude death phenomenon in a nonautonomous chained network with complicated piecewise nonlinear coupling functions. An analytical criterion for the boundary of the amplitude death region is derived by using the average method. The mechanism of the amplitude death in the nonautonomous networks is very different from that of autonomous systems and rapid dynamic transitions could halt the amplitude death. Numerical verifications are carried out to check jump transitions among different solution branches and further confirm the correctness of the theoretical results.

Evidence for high-energy extraterrestrial neutrinos at the IceCube detector

We report on results of an all-sky search for high-energy neutrino events interacting within the IceCube neutrino detector conducted between May 2010 and May 2012. The search follows up on the previous detection of two PeV neutrino events, with improved sensitivity and extended energy coverage down to about 30 TeV. Twenty-six additional events were observed, substantially more than expected from atmospheric backgrounds. Combined, both searches reject a purely atmospheric origin for the 28 events at the 4σ level. These 28 events, which include the highest energy neutrinos ever observed, have flavors, directions, and energies inconsistent with those expected from the atmospheric muon and neutrino backgrounds. These properties are, however, consistent with generic predictions for an additional component of extraterrestrial origin.

Measurement of atmospheric neutrino oscillations with IceCube

We present the first statistically significant detection of neutrino oscillations in the high-energy regime (>20 GeV) from an analysis of IceCube Neutrino Observatory data collected in 2010 and 2011. This measurement is made possible by the low-energy threshold of the DeepCore detector (~20 GeV) and benefits from the use of the IceCube detector as a veto against cosmic-ray-induced muon background. The oscillation signal was detected within a low-energy muon neutrino sample (20-100 GeV) extracted from data collected by DeepCore. A high-energy muon neutrino sample (100 GeV-10 TeV) was extracted from IceCube data to constrain systematic uncertainties. The disappearance of low-energy upward-going muon neutrinos was observed, and the nonoscillation hypothesis is rejected with more than 5σ significance. In a two-neutrino flavor formalism, our data are best described by the atmospheric neutrino oscillation parameters |Δm(32)(2)|=(2.3(-0.5)(+0.6))×10(-3) eV(2) and sin(2)(2θ(23))>0.93, and maximum mixing is favored.

First observation of PeV-energy neutrinos with IceCube

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of 1.04±0.16 and 1.14±0.17 PeV, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ν(e,μ,τ) (ν(e,μ,τ)) or charged-current ν(e) (ν(e)) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is 0.082±0.004(stat)(-0.057)(+0.041)(syst). The probability of observing two or more candidate events under the atmospheric background-only hypothesis is 2.9×10(-3) (2.8σ) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

Measurement of the atmospheric νe flux in IceCube

We report the first measurement of the atmospheric electron neutrino flux in the energy range between approximately 80 GeV and 6 TeV, using data recorded during the first year of operation of IceCube's DeepCore low-energy extension. Techniques to identify neutrinos interacting within the DeepCore volume and veto muons originating outside the detector are demonstrated. A sample of 1029 events is observed in 281 days of data, of which 496±66(stat)±88(syst) are estimated to be cascade events, including both electron neutrino and neutral current events. The rest of the sample includes residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is consistent with models of atmospheric neutrinos in this energy range. This constitutes the first observation of electron neutrinos and neutral current interactions in a very large volume neutrino telescope optimized for the TeV energy range.

Search for dark matter annihilations in the sun with the 79-string IceCube detector

We have performed a search for muon neutrinos from dark matter annihilation in the center of the Sun with the 79-string configuration of the IceCube neutrino telescope. For the first time, the DeepCore subarray is included in the analysis, lowering the energy threshold and extending the search to the austral summer. The 317 days of data collected between June 2010 and May 2011 are consistent with the expected background from atmospheric muons and neutrinos. Upper limits are set on the dark matter annihilation rate, with conversions to limits on spin-dependent and spin-independent scattering cross sections of weakly interacting massive particles (WIMPs) on protons, for WIMP masses in the range 20-5000  GeV/c2. These are the most stringent spin-dependent WIMP-proton cross section limits to date above 35  GeV/c2 for most WIMP models.

Transcriptome analysis of the Chinese white wax scale Ericerus pela with focus on genes involved in wax biosynthesis

Background

The Chinese white wax scale, Ericerus pela Chavannes is economically significant for its role in wax production. This insect has been bred in China for over a thousand years. The wax secreted by the male scale insect during the second-instar larval stage has been widespread used in wax candle production, wax printing, engraving, Chinese medicine, and more recently in the chemical, pharmaceutical, food, and cosmetics industries. However, little is known about the mechanisms responsible for white wax biosynthesis. The characterization of its larval transcriptome may promote better understanding of wax biosynthesis.

Methodology/Principal Findings

In this study, characterization of the transcriptome of E. pela during peak wax secretion was performed using Illumina sequencing technology. Illumina sequencing produced 41,839 unigenes. These unigenes were annotated by blastx alignment against the NCBI Non-Redundant (NR), Swiss-Prot, KEGG, and COG databases. A total of 104 unigenes related to white wax biosynthesis were identified, and 15 of them were selected for quantitative real-time PCR analysis. We evaluated the variations in gene expression across different development stages, including egg, first/second instar larvae, male pupae, and male and female adults. Then we identified five genes involved in white wax biosynthesis. These genes were expressed most strongly during the second-instar larval stage of male E. pela.

Conclusion/Significance

The transcriptome analysis of E. pela during peak wax secretion provided an overview of gene expression information at the transcriptional level and a resource for gene mining. Five genes related to white wax biosynthesis were identified.

Stability and chaotification of vibration isolation floating raft systems with time-delayed feedback control

This paper presents a systematic study on the stability of a two-dimensional vibration isolation floating raft system with a time-delayed feedback control. Based on the generalized Sturm criterion, the critical control gain for the delay-independent stability region and critical time delays for the stability switches are derived. The critical conditions can provide a theoretical guidance of chaotification design for line spectra reduction. Numerical simulations verify the correctness of the approach. Bifurcation analyses reveal that chaotification is more likely to occur in unstable region defined by these critical conditions, and the stiffness of the floating raft and mass ratio are the sensitive parameters to reduce critical control gain.

A methodology to model causal relationships on offshore safety assessment focusing on human and organizational factors

INTRODUCTION

Focusing on people and organizations, this paper aims to contribute to offshore safety assessment by proposing a methodology to model causal relationships.

METHOD

The methodology is proposed in a general sense that it will be capable of accommodating modeling of multiple risk factors considered in offshore operations and will have the ability to deal with different types of data that may come from different resources. Reason's "Swiss cheese" model is used to form a generic offshore safety assessment framework, and Bayesian Network (BN) is tailored to fit into the framework to construct a causal relationship model. The proposed framework uses a five-level-structure model to address latent failures within the causal sequence of events. The five levels include Root causes level, Trigger events level, Incidents level, Accidents level, and Consequences level. To analyze and model a specified offshore installation safety, a BN model was established following the guideline of the proposed five-level framework. A range of events was specified, and the related prior and conditional probabilities regarding the BN model were assigned based on the inherent characteristics of each event.

RESULTS

This paper shows that Reason's "Swiss cheese" model and BN can be jointly used in offshore safety assessment. On the one hand, the five-level conceptual model is enhanced by BNs that are capable of providing graphical demonstration of inter-relationships as well as calculating numerical values of occurrence likelihood for each failure event. Bayesian inference mechanism also makes it possible to monitor how a safety situation changes when information flow travel forwards and backwards within the networks. On the other hand, BN modeling relies heavily on experts' personal experiences and is therefore highly domain specific.

IMPACT ON INDUSTRY

"Swiss cheese" model is such a theoretic framework that it is based on solid behavioral theory and therefore can be used to provide industry with a roadmap for BN modeling and implications. A case study of the collision risk between a Floating Production, Storage and Offloading (FPSO) unit and authorized vessels caused by human and organizational factors (HOFs) during operations is used to illustrate an industrial application of the proposed methodology.

Aplastic anaemia associated with parvovirus B19 infection

Parvovirus B19 involvement was investigated in 30 children with severe aplastic anaemia. Active or recent parvovirus B19 infection, as shown by B19 DNA viraemia, positive B19 specific IgM antibodies, or both, was diagnosed in six patients. There were no other plausible causes. We suggest that parvovirus B19 infection might be associated with severe aplastic anaemia.

Lymphoproliferative responses in pigs infected with Mycobacterium avium

Naturally infected cases of swine mycobacteriosis were divided into two groups, localized infection (LI) and disseminated infection (DI). Lymphoproliferative response (LPR) was then examined to estimate their immunological states. Both control and LI groups showed strong response to Concanavalin A (Con A) and phytohemagglutinin (PHA) in the LPR, and lymphocytes recovered from the LI responded well to purified protein derived from M. avium (PPD). On the other hand, the DI group showed weak response to both Con A and PHA, despite their strong response to PPD stimulation. These data suggest that the low LPR to Con A and PHA observed in the DI groups was probably not due to the general unresponsiveness of T-cells.

Chemical composition of endotoxins produced by Fusobacterium necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme

The endotoxins from two recently-classified subspecies of Fusobacterium, namely F. necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme, were compared. Chemical analysis of the isolated endotoxins revealed that they were clearly different. Distinct levels of polysaccharides were demonstrated. The endotoxins isolated were devoid of heptose and 3-deoxy-D-manno-octulosonate (KDO). The endotoxins of F. n. necrophorum and F. n. funduliforme contained lipid A in a ratio of 4:1 which may account for the variations in their virulence.

[Expression of cyclin dependent kinase inhibitor p27 during proliferation in vascular smooth muscle cell]

This study was to investigate cell cycle distribution of the vascular smooth muscle cells (VSMCs) and negative regulator of cell proliferation p27 expression caused by platelet derived growth factor BB (PDGF-BB), angiotensin II (Ang II) and arginine vasopressin (AVP). Deprived of fotal calf serum for 48 h, cultured VSMCs in quiescent condition were collected at different times after stimulation of Ang II, AVP and PDGF-BB. Cell cycle distribution and p27 expression were determined with a flow cytometer. The results showed that the protein content of VSMCs was significantly increased (43.6%) by Ang II as a result of hypertrophy, but Ang II did not lead to downregulation of p27. AVP could downregulate p27 slightly. PDGF could inhibit p27 expression significantly and cause VSMCs hyperplasia. These results suggest that the progression of VSMCs through G1 to S phase might be brought out by the inhibition of p27 during proliferation.

Sequence analysis and expression of Nramp-1 gene in Bcgr and Bcgs mice

Nucleic acid sequence of complemental DNA open reading frame for Nramp-1 gene was compared among DBA/2 (Bcgr), C57BL/6 (Bcgs) and C57BL/6-Bcgr mice which was previously developed as M. avium-resistant mouse strain (Xu, et al. Veterinary Microbiology 50:73-79 (1996). Total RNA was isolated from various organs of DBA/2, C57BL/6 and C57BL/6-Bcgr. Nramp-1 cDNA was constructed from their mRNAs by gene amplification (PCR) technique and their open reading frame sequences were compared. The results clearly showed that our C57BL/6-Bcgr was almost identical with the DNA sequence of the DBA/2 mice. In contrast, C57BL/6-Bcgs mice differed only on the substitution of adenine for guanine of the nucleic acid at position 596. This corresponded to the site of amino acid substitution (glycine to asparate) at position 169 in predicted NRAMP which had been reported. The expression of Nramp-1 mRNA was more prominent in spleens and livers and there appeared to be no significant difference among the strains of mice.

[Study of the bone formation and osteogenesis after transplantation of human periosteal mesenchymal stem cells]

OBJECTIVE

To study the bone formation and osteogenesis after transplantation of human periosteal mesenchymal stem cells(PMSC).

METHODS

Suspension of PMSC which obtained from cell culture of periosteal segments in vitro were injected into the backs of nude mice subcutaneously, and the fracture site of neck of femur in old person.

RESULTS

Subdermal nodules were observed by naked eyes after 11 days of transplantation. 4 weeks later, their anatomic diameter reached 2-7 mm(averaged 3.6 mm). It was proved that the subdermal nodules were trabecular ball trapped with fibrous tissue. The nodules were investigated by human special apoB gene with PCR, and the test of anti-human-tissue precipitin reaction(AHTPR). The results of PCR and AHTPR were positive reaction. There were no subdermal nodules formed in the sites of injection of frozen-melted PMSC or culture medium. The new callus in the sites of fracture were tested by PCR test, and two kinds of apoB gene products were detected.

CONCLUSION

The results indicated that the implanted PMSC could form new bone directly in nude mice, and the cells of donor and recipient all could form new bone.

The erythrocyte receptor for Fusobacterium necrophorum hemolysin: phosphatidylcholine as a possible candidate

An attempt was made to determine the receptor for the hemolysin of Fusobacterium necrophorum using horse erythrocyte or its membranes as target. The spectrum of erythrocyte sensitivity has indicated that horse, dog and mouse erythrocytes are highly sensitive whereas cattle, sheep, goat and chicken red blood cells are insensitive to this hemolysin. A high correlation between sensitivity and phosphatidylcholine content of the erythrocyte membranes was noted. Binding of hemolysin to horse erythrocyte membranes was reduced significantly by prior treatment of membranes with phospholipase A2 but not with phospholipase C. Pretreatment of erythrocyte membranes with pronase, proteinase K, trypsin or neuraminidase did not alter binding of hemolysin to the membranes, suggesting that protein or sialyl residues are not involved as receptors. Gas liquid chromatography analysis showed that the fatty acid profile from hydrolysis of bovine liver phosphatidylcholine by hemolysin and phospholipase A2 were similar. In conclusion, this report presents evidence that phosphatidylcholine may be acting as a possible receptor for the hemolysin of F. necrophorum.