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.

[Comparison of maternal-fetal outcomes between laparoscopic cervicoisthmic cerclage and McDonald cerclage in women with cervical insufficiency]

Objective: To compare the maternal and fetal outcomes of women with cervical insufficiency (CI) undergoing McDonald cerclage (MC) and laparoscopic cervicoisthmic cerclage (LCC), so as to provide evidence for the selection of cerclage methods. Methods: A retrospective trial was carried out in the First Affiliated Hospital of Sun Yat-sen University from January 2010 to December 2020. A total of 221 women who underwent the prophylactic cerclage were divided into MC group (n=54), LCC with MC history group (n=28) and LCC without MC history group (n=129) by the mode of operation and whether the pregnant women who underwent LCC had MC history. General clinical data, pregnancy complications and pregnancy outcomes were compared between the three groups. Results: (1) General clinical data: the proportion of women accepted cervical cerclage during pregnancy in MC group, LCC with MC history group and LCC without MC history group were 100.0% (54/54), 7.1% (2/28) and 27.1% (35/129), respectively (P<0.001). The indications of the three groups showed statistical significance (P=0.003), and the main indication was the history of abortion in the second and third trimester [75.9% (41/54) vs 89.3% (25/28) vs 84.5% (109/129)]. (2) Pregnancy complications: the incidence of abnormal fetal position [7.8% (4/51) vs 17.4% (4/23) vs 19.8% (24/121)], placenta accrete [5.9% (3/51) vs 13.0% (3/23) vs 11.6% (14/121)], uterine rupture [0 vs 4.3% (1/23) vs 5.8% (7/121)] in the MC group were all lower than those in LCC with MC history and LCC without MC history groups. However, there were no statistical significances (all P>0.05). Intrauterine inflammation or chorioamnionitis [15.7% (8/51) vs 0 vs 0.8% (1/121)] and premature rupture of membrane [23.5% (12/51) vs 4.3% (1/23) vs 0] were both significantly higher in MC group than those in LCC with MC history and LCC without MC history groups (all P<0.001). (3) Pregnancy outcomes: the cesarean section rate was significantly lower in MC group (41.2%, 21/51) than that in LCC with MC history group (100.0%, 23/23) and LCC without MC history group (100.0%, 121/121; P<0.001). MC group was associated with lower expenditure than LCC with MC history and LCC without MC history groups (12 169 vs 26 438 vs 27 783 yuan, P<0.001). The success rates of live birth cerclage did not differ significantly in MC (94.4%, 51/54), LCC with MC history (82.1%, 23/28) and LCC without MC history (93.8%, 121/129) groups (χ²=5.649, P=0.059). There was no significant difference in neonatal intensive care unit occupancy, neonatal birth weight and neonatal asphyxia between the three groups (all P>0.05). Conclusions: Both LCC and MC are the treatment choice for women with CI, which may get similar liver birth. However, MC has the advantages of low cesarean section rate, economical and easy operation. Therefore, MC is recommended as the first choice for CI patients, and LCC is for women with failed MC.

A nomogram for predicting overall survival in patients with type II endometrial carcinoma: a retrospective analysis and multicenter validation study

OBJECTIVE

Type II endometrial cancer (EC) is associated with high risk of metastasis and poor prognosis. We aimed to develop a nomogram for predicting survival probability in patients with type II EC.

PATIENTS AND METHODS

Data from a total of 4,117 patients with confirmed type II EC were pulled from the Surveillance, Epidemiology, and End Results (SEER) database, and were randomly divided into a training set and an internal verification set. A nomogram was constructed based on the training set. The concordance index (C-index), area under the ROC curve, and calibration plots were used to evaluate the identification and calibration of the nomogram. The SEER internal validation set and the Chinese multicenter data set (74 patients) were used to verify discriminations and corrections of the model.

RESULTS

Multivariate analysis indicated that age, marital status, tumor size, T stage, N stage, M stage, surgery, radiotherapy, and chemotherapy were independent factors affecting the prognosis of type II EC patients (p<0.001). The corresponding nomogram has showed excellent calibration and discrimination (C-index [95% CI], 0.752 [0.738-0.766]). The model was verified in the internal verification set (0.760 [0.739-0.781]) and the Chinese multicenter set (0.784 [0.607-0.961]). In addition, the AUC further confirmed the accuracy of the nomogram in predicting survival. The calibration curve of OS within 5 years confirmed good calibration of the nomogram.

CONCLUSIONS

This model and the corresponding risk classification system may provide useful tools for clinicians to evaluate the long-term prognosis of patients and carry out personalized clinical evaluation.

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.

[Application of indocyanine green fluorescence visualization in surgical resection of abdominal wall endometriosis]

Objective: To investigate the feasibility, effectiveness and safety of indocyanine green (ICG) navigation in the surgical resection of abdominal wall endometriosis (AWE). Methods: Seven women undergoing surgery for AWE in First Affiliated Hospital of Sun Yat-sen University (from July 1, 2021 to October 1, 2021) were collected. After exposure of the focus, ICG were used intravenously (0.25 mg/kg) as fluorescent dye for the intraoperative evaluation of AWE vascularization. Resection of the AWE was guided by direct visualization of the focus under standard laparoscopy with a near-infrared (NIR) camera head. Surgical margin around the AWE (3, 6, 9 and 12 point) and the margin under the focus were obtained for postoperative pathological examination of endometriosis. Time from injection to fluorescence visualization, the proportion of fluorescence visualization, time of fully resection of AWE, side effects related to the use of ICG, perioperative complications as well as the pathological result of the surgical margins were recorded. Results: ICG fluorescence of the AWE were seen in 5 patients (5/7). The mean time from injection to fluorescence visualization was (46.7±9.8) s. The mean time of fully resection of AWE was (16.4±7.0) minutes. There were no side effects related to the use of ICG. The rate of class-A wound healing was 7/7. All of the surgical margins were confirmed endometriosis-negative by postoperative pathological examination. Conclusion: ICG fluorescence visualization could conduct accurate resection of AWE, which is clinically safe and effective.

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.

[The application value of multi-material artifact reduction technique in maxillofacial CT images of patients with metallic dental implants]

Objective: To investigate the effect of multi-material artifact reduction (MMAR) technique on the maxillofacial CT images of patients with metallic dental implants. Methods: The data of 30 patients with metal denture implants who underwent maxillofacial wide-detector CT scans in the Department of Radiology of the First Affiliated Hospital of Zhengzhou University from March 2019 to February 2020 were retrospectively collected. The images of the lesion sites of patients were all affected by the metal implants artifacts. The 120 kV-like, virtual monoenergetic images (VMI) (70, 90, 110 keV), VMI (70, 90, 110 keV)+MMAR images were reconstructed at venous phase by energy spectrum scanning. A total of 7 image sequences were obtained for each patient. The CT value and noise value of the lesion and the longus capitis muscle on the same plane were measured, and the artifact index (AI) of lesion was calculated.Friedman test and Wilcoxon test were used to evaluate image quality objectively and subjectively. Results: There were significant differences in SD and AI among the 7 groups (χ²=133.800,P<0.001;χ²=92.147,P<0.001). The SD[10 (8, 12)] and AI [6 (5, 9)]of VMI 110 keV+M images were the lowest, but there were no significant differences in AI between VMI 110 keV+M and VMI 90 keV+M image (P= 0.271). The SD and AI of VMI+M group were lower than those in VMI group (all P<0.05). There was significant difference in image score among the 7 groups (χ ² = 151.199, P<0.001). The image scores of VMI (70, 90, 110 keV)+M group were higher than those of VMI group (Z=-4.583, P = 0.000; Z=-3.742, P = 0.000; Z =-2.449, P = 0.014). The subjective score of VMI 90 keV+M [4 (3, 4)] was the highest, higher than those of other 6 groups (all P<0.05), in 26 out of 30 cases, lesions displayed clear contrast, and the artifacts eliminated completely. Conclusion: The MMAR technique of wide-detector CT might effectively remove the metallic dental implants artifacts and improve the image quality. VMI 90 keV+MMAR images could achieve the best artifact removal effect and good tissue contrast.

MiRNA-93 functions as an oncogene in glioma by directly targeting RBL2

OBJECTIVE

Glioma is a tumor of the brain. Although the clinical regimens and surgical techniques for glioma have improved, therapies of advanced glioma remain challenging, carrying dismal overall survival and therapeutic success rates. Evidence has shown that miRNAs played important roles in glioma development. The current study aimed at investigating the function of a novel cancerogenic miRNA, miR-93, in glioma progression by investigating the expression and mechanism of it.

PATIENTS AND METHODS

qRT-PCR was conducted to assess the miR-93 expression and the mRNA expression of target gene in glioma tissues and cells. The invasion and migration abilities of the glioma cells were determined by transwell assays. Luciferase reporter assay was performed to confirm the target of miR-93.

RESULTS

The results indicated that miR-93 expression in glioma tissues and cells was increased significantly than that in normal brain tissues and cells. Furthermore, miR-93 promoted glioma cell migration and invasion. RBL2 was recognized as a direct target of miR-93 in glioma cells, and overexpression of RBL2 could reverse the stimulative effect of miR-93 in glioma cell.

CONCLUSIONS

The above findings suggested that miR-93 together with RBL2 could be diagnostic targets and novel prognostic markers for glioma.

[Water sorption and hygroscopic changes of five core buildup composite resins]

Objective: To evaluate water sorption and hygroscopic dimensional changes of five core buildup composite resins, and to provide references for material modification on water sorption. Methods: Five commercial core buildup materials (group A: Smart Dentin Replacement(TM); group B: NanoFil; group C: ParaCore(TM); group D: LuxaCore Z; group E: EmbraceCore(TM) Resin Cement) were fabricated to disk-shaped specimens: (15.0±0.1) mm diameter, (2.0±0.1) mm thickness (n=10). Specimens were thoroughly irradiated with curing lights. The initial mass in air was recorded, and the initial mass in deionized water was recorded. Five specimens of each group were immersed in deionized water for 28 d. They were weighed as a function of different immersion time (1, 2, 3, 4, 5, 6, 7, 14, 28 d). The mass in air was recorded, and the displayed mass in deionized water was recorded. Archimedes' principle was applied to calculate the dimensional changes. The other five specimens of each group were stored in artificial saliva and were tested by the same methods. Results: All specimens gained weight and hygroscopic changes during 28 d immersion. When stored in deionized water, the apparent mass change of group A [(10.6±0.9) μg/mm(3)] and the dimensional change of group A [(0.39±0.10)%] were the lowest, while the mass change of group E [(48.0±0.2) μg/mm(3)] and the dimensional change of group E [(3.16±0.13)%] were the highest (P<0.05). In artificial saliva, the lowest apparent mass change was found in group A [(11.8±1.0) μg/mm(3)] while the highest change was found in group E [(47.4±3.5) μg/mm(3)] (P<0.05). The lowest dimensional change was found in group C [(0.37±0.09)%] and the highest was found in group E [(3.07±0.19)%] in artificial saliva (P<0.05). Conclusions: Water sorption and dimensional changes vary in immersion fluids with different osmotic pressure. Water sorption and dimensional changes of core buildup composite resins are highly correlated with test materials in both of the deionized water and artificial saliva.

[Analysis on influencing factors of prognosis of patients with acute organophosphorus pesticide poisoning]

OBJECTIVE

To analyze the relationship between risk factors and prognosis of acute organophosphorus pesticide poisoning (AOPP).

METHODS

The clinical data including APACHEⅡ, D-dimer, C-reactive protein, procalcitonin, lactic acid of the 67 cases of acute organophosphorus pesticide poisoning which respectively divided into survival group and death group by the outcome were collected. The independent influcing factors were got by logistic regression analysis.

RESULTS

The analysis showed that APACHEⅡ, D-dimer、C-reactive protein and Procalcitonin were influencing factors to evaluate prognosis of AOPP (P<0.05) .Meanwhile, APACHEⅡ and CRP were the independent influencing factors to evaluate prognosis of AOPP (P<0.05). APACHEⅡ26was the optimum thresholds to acess the prognosis of AOPP and its Youden index was largest.

CONCLUSION

APACHEⅡ and CRP played an important role in the assessment of prognosis on AOPP. When APACHEⅡwas more than 26, it suggested the patient of AOPP will have a bad prognosis.

Geniposide promotes beta-cell regeneration and survival through regulating β-catenin/TCF7L2 pathway

T-cell factor 7-like 2 (TCF7L2) is an important transcription factor of Wnt/β-catenin signaling, which has critical roles in β-cell survival and regeneration. In preliminary screening assay, we found geniposide, a naturally occurring compound, was able to increase TCF7L2 mRNA level in Min6 cells. Here we aimed to investigate the role of geniposide in β-cell and underlying mechanism involved. Geniposide was found to promote β-cell survival by increasing β-cell proliferation and decreasing β-cell apoptosis in cultured mouse islets after challenge with diabetic stimuli. Geniposide protected β-cell through activating Wnt signaling, enhanced expressions of TCF7L2 and GLP-1R, activated AKT, inhibited GSK3β activity, and promoted β-catenin nuclear translocation. The protective effect of geniposide was remarkably suppressed by siRNAs against β-catenin, or by ICG001 (β-catenin/TCF-mediated transcription inhibitor). Moreover, geniposide promoted β-cell regeneration in vivo to normalize blood glucose in high-fat diet and db/db mice. Increased β-cell proliferation was observed in pancreatic sections of geniposide-treated diabetic mice. Most importantly, geniposide triggered small islet-like cell clusters formation as a result of β-cell neogenesis from ductal epithelium, which was well correlated with the increase in TCF7L2 expression. In exocrine cells isolated from mouse pancreas, geniposide could induce duct cell differentiation through upregulating TCF7L2 expression and activating JAK2/STAT3 pathway. Taken together, we identified a novel role of geniposide in promoting β-cell survival and regeneration by mechanisms involving the activation of β-catenin/TCF7L2 signaling. Our finding highlights the potential value of geniposide as a possible treatment for type 2 diabetes.

Dynamically controlled resonance fluorescence spectra from a doubly dressed single InGaAs quantum dot

We report the first experimental demonstration of the interference-induced spectral line elimination predicted by Zhu and Scully [Phys. Rev. Lett. 76, 388 (1996)] and Ficek and Rudolph [Phys. Rev. A 60, R4245 (1999)]. We drive an exciton transition of a self-assembled quantum dot in order to realize a two-level system exposed to a bichromatic laser field and observe the nearly complete elimination of the resonance fluorescence spectral line at the driving laser frequency. This is caused by quantum interference between coupled transitions among the doubly dressed excitonic states, without population trapping. We also demonstrate a multiphoton ac Stark effect with shifted subharmonic resonances and dynamical modifications of resonance fluorescence spectra by using double dressing.

Spectrum and features of congenital heart disease in Xi'an, China as detected using fetal echocardiography

This study aimed to investigate the spectrum and features of congenital heart disease (CHD) in Xi'an, China using fetal echocardiography. All pregnant women referred for fetal echocardiography underwent a systematic fetal echocardiographic examination. Each case of complex defects was diagnosed according to the predominant pathophysiology, and the overall frequency of each defect was recorded and classified according to its location in the fetal heart. CHD was diagnosed in 195 fetuses. The top 5 types of CHD were, in order, single ventricle (15.9%, 31/195), atrioventricular septal defect (12.3%, 24/195), ventricular septal defect (VSD) (11.8%, 23/195), tetralogy of Fallot (10.8%, 21/195), and double-outlet right ventricle (8.2%, 16/195). The 195 cases of CHD comprised 316 defects in total. The most common defect was ventricular malformation (40.5%, 128/316), followed by great artery anomalies (38.0%, 120/316), endocardial cushion abnormalities (11.7%, 37/316), atrial abnormalities (6.6%, 21/316), and semilunar valve abnormalities (3.2%, 10/316). VSD accounted for the largest proportion (24.4%, 77/316) of the ventricular malformations. The total proportion of obstructive lesions in this group was much higher for the right than for the left side of the heart (18.4% (58/316) vs 9.5% (30/316), respectively). The spectrum of fetal CHD detected by echocardiography was much different compared to that accepted in the past. Complex defects were more common prenatally. Ventricular malformations were the largest constituent of all of the defects associated with fetal CHD, and VSD was the most common component of complex defects. Chinese fetal CHD encompassed more right-sided than left-sided obstructive lesions.

Indistinguishable tunable single photons emitted by spin-flip Raman transitions in InGaAs quantum dots

This Letter reports all-optically tunable and highly indistinguishable single Raman photons from a driven single quantum dot spin. The frequency, linewidth, and lifetime of the Raman photons are tunable by varying the driving field power and detuning. Under continuous-wave excitation, subnatural linewidth single photons from off-resonant Raman scattering show an indistinguishability of 0.98(3). Under π pulse excitation, spin- and time-tagged Raman fluorescence photons show an almost vanishing multiphoton emission probability of 0.01(2) and a two-photon quantum interference visibility of 0.95(3). Lastly, Hong-Ou-Mandel interference is demonstrated between two single photons emitted from remote, independent quantum dots with an unprecedented visibility of 0.87(4).

Catechin stimulates osteogenesis by enhancing PP2A activity in human mesenchymal stem cells

SUMMARY

Using human mesenchymal stem cells, we identified catechin from a panel of herbal ingredients and Chinese traditional compounds with the strongest osteogenic effects. Catechin increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further clarified the signaling pathway that catechin mediated to stimulate osteogenesis.

INTRODUCTION

Human mesenchymal stem cells (hMSCs), useful as a species specific cell culture system for studying cell lineage differentiation, were examined as a tool to identify novel herbal ingredients and Chinese traditional compounds for enhancing osteogenesis.

METHODS

Immortalized and primary hMSCs were induced in osteogenic induction medium in the presence of a variety of herbal ingredients and Chinese traditional compounds and osteogenic differentiation was evaluated by histochemical assays and quantitative RT-PCR.

RESULTS

Using immortalized hMSCs, we first identified catechin, 18β-glycyrrhetinic acid, baishao, and danggui with osteogenic properties, which enhanced calcium deposition at the dose without significant cytotoxic effects. Primary hMSCs were then applied for confirming the osteogenic effects of catechin, which increased alkaline phosphatase activity, calcium deposition, and mRNA expression of Runx2 and osteocalcin. We further found the extracellular signal-regulated kinase (ERK) pathway was downregulated upon stimulation with catechin. Catechin increased the level and activity of protein phosphatases 2A (PP2A) that dephosphorylates ERK kinase (MEK) and ERK. Further, PP2A inhibitor, okadaic acid, abolished the effect of catechin-mediated inactivation of ERK and stimulation of osteogenesis. The blocking effect of okadaic acid on osteogenesis was further reversed by PD98059, a specific inhibitor of MEK. Co-immunoprecipitation revealed the association of PP2A to both MEK and ERK.

CONCLUSIONS

These studies propose catechin enhanced osteogenesis by increasing the PP2A level that inhibits the MEK and ERK signaling in hMSCs. These results prove the concept of using hMSCs as a convenient tool for rapid and consistent screening of the osteogenic herbal ingredients and traditional Chinese compounds.

Comparison between cells and cancer stem-like cells isolated from glioblastoma and astrocytoma on expression of anti-apoptotic and multidrug resistance-associated protein genes

This study is to explore and compare the features of the cells and cancer stem-like cells (CSCs) isolated from both glioblastoma and astrocytoma on expression of anti-apoptotic and multidrug resistance-associated protein (MRP) genes. As a result, the mRNA expression of livin, livinalpha and MRP1 was up-regulated in human CSCs from 2 times to 85 times, but the gene expression of MRP3 was down-regulated from 0.09 times to 0.5 times. After just differentiation the mRNA expression of livin, livinalpha and MRP3 was up-regulated from 9 times to 64 times, but the mRNA expression of MRP1 was down-regulated from 0.01 times to 0.03 times. It is a rare report that glioma stem-like cells can be induced successfully from a grade 2-3 astrocytoma tissue. The properties of glioblastoma and astrocytoma stem-like cells on anti-apoptotic and MRP genes are: anti-apoptotic gene livin and survivin are elevated in CSCs but are the most increased in just differentiated CSCs; MRP1 gene is significantly increased and MRP3 is decreased in CSCs, but when differentiating the MRP3 gene starts a remarkable increase in CSCs; the expression of anti-apoptotic and MRP genes shows no differences between the CSCs isolated from glioblastoma and astrocytoma tissues.

Proteomic analysis of low-abundant integral plasma membrane proteins based on gels

To characterize low-copy integral membrane proteins and offer some methods for human liver proteome projects, we fractionated highly purified rat liver plasma membrane (PM). PM was purified through two sucrose density gradient centrifugations, and treated with 0.1 M Na(2)CO(3), chloroform/methanol and Triton X-100. Proteins were separated by electrophoresis and submitted to mass spectrometry analysis. Four hundred and fifty-seven non-redundant membrane proteins were identified, of which 23% (105) were integral membrane proteins with one or more transmembrane domains. One hundred and fifty-three (33.5%) had no location annotation and 68 were unknown-function proteins. The proteins from different fractions were complementory. A database search for all identified proteins revealed that 53 proteins were involved in the cell communication pathway. More interestingly, more than 50% of the proteins had a protein abundance index concentration of less than 0.1 mol/l, and 12% proteins a concentration 100 times less than that of arginase 1 and actin.

Gene suture--a novel method for intramuscular gene transfer and its application in hypertension therapy

In this report, reporter gene beta-galactosidase (LacZ) was chosen to compare two different intramuscular gene transfer methods, direct injection and gene suture. Evidence showed that gene suture can produce a higher foreign gene express efficiency in skeletal muscle compared with the direct injection method. The highly efficient eukaryotic expressing vectors of human atrial natriuretic factor (ANF) were constructed (pcD2/pAdVAntage/hANF and pcDNA3/hANF), and in vivo ANF gene delivery was performed by intramuscular gene suture. The effects of ANF gene transfer on blood pressure and renal sodium and water excretion were studied in three models of hypertensive animals. Results showed that a marked decrease of mean arterial pressure (MAP) and a significant increase of urine volume and urinary sodium excretion was produced in rats receiving the hANF construct due to the local expression of ANF and its secretion into plasma. Taken together, these results indicate that gene suture may represent a novel gene delivery modality in gene therapy.

[Effect of adrenomedullin on mesenteric microvessels and microlymphatics in rat]

The dilatant effect of adrenomedullin (ADM), a novel peptide of 52 amino acids, on the mesenteric microvessels and microlymphatics was investigated under microscopic observation. 10(-6) mol/L ADM could also ameliorate alteration of the hemorheology induced by 10(-5) mol/L norepinephrine (NE) or 10(-7) mol/L endothelin (ET). However, this ameliorative response was markedly inhibited in the presence of NG-nitro-L-arginine (L-NNA), an inhibitor for production of nitric oxide.

Hemodynamic effects of centrally administered adrenomedullin (13-52) in anesthetized rats

This study was conducted to investigate the effect of intracerebroventricular administration of adrenomedullin (13-52) [ADM(13-52)], a novel hypotensive peptide, on the hemodynamic parameters of anesthetized rats. ADM(13-52) was administered centrally in a dose of 0.4-3.2 nmol/kg. It provoked marked, prolonged and dose-dependent increases in mean arterial blood pressure, heart rate, stroke volume, cardiac index, left ventricular pressure, left ventricular dp/dtmax and dp/dtmin, but reduction in total peripheral resistance index. In addition, intracerebroventricular administration of ADM(13-52; 1.6 nmol/kg) provoked a marked increase in renal sympathetic nerve activity. Intracerebroventricular administration of artificial cerebrospinal fluid had no effect on the hemodynamic parameters and renal sympathetic nerve activity. The results indicate that ADM(13-52) exerts a central action on the cardiovascular system. The mechanisms of hemodynamic changes induced by central ADM(13-52) were preliminarily analyzed in this study. ADM might play a role in the central control of the cardiovascular system, although the confirmed mechanisms and the physiological implications are undetermined.

[Observation on hypotensive action of adrenomedullin and its distribution in tissues]

The effect of adrenomedullin (AM) on blood pressure and tension of aortic rings were studied in normal and in either spontaneous or renal hypertensive rats (SHR/RHR). The distribution characteristics of AM in viscera was also investigated. It was found that the hypotensive action of AM was far more prominent in hypertensive than in normotensive rats. The tension lowering action on the aortic rings is dose dependent and requires the presence of endothelium. Immunohistochemistry reactivity of AM of different degrees were also found in lung, kidney and myocardium, in addition to cells of pheochromocytoma and adrenomedulla. It was suggested that AM may play an important role in the regulation of blood pressure and visceral blood circulation.

[Protective effect of tetrandrine on pancreatic islet cells damaged by alloxan in rats]

Tetrandrine (TET, 100 mg/kg) injected intraperitoneally could prevent rats from diabetes induced by alloxan. After 48 h of injection of alloxan, the blood sugar of the preventive group decreased from the control value of 25.46 +/- 1.21 mmol/L to 7.63 +/- 0.44 mmol/L (P < 0.001) while the serum insulin level increased to 11.33 +/- 1.97 microU/ml and the plasma glucagon concentration to 66.85 +/- 5.07 pg/ml respectively from the control group's value of 7.13 +/- 0.45 microU/ml and 90.35 +/- 8.33 pg/ml. In glucose tolerance test, TET 100 mg/kg showed that the abnormal glucose tolerance induced by alloxan could be improved. The blood sugar area under the glucose tolerance curve of the preventive group decreased from the control groups level of 113.28 +/- 5.02 mmol.h/L to 29.45 +/- 1.63 mmol.h/L (P < 0.001). Immunohistochemical observation of islet beta cells confirmed that TET could markedly prevent beta cells from injuries induced by alloxan and there was no obvious change in the appearance of islet beta cells in the preventive group. The above results suggested that TET could protect pancreatic islet beta cells from injuries caused by Alloxan.

[Protective effect of verapamil against alloxan-induced damage on pancreatic islet beta-cells in rats]

An experimental diabetes model was produced by intravenous injection of alloxan. Verapamil (40 mg/kg) administered intraperitoneally 30 minutes prior to alloxan was able to decrease serum glucose from 22.93 +/- 1.37 mmol/L to 8.79 +/- 0.83 mmol/L after 48 hours of injection of alloxan. Histological findings showed that the number of secretory granules in beta cells of the pancreatic islet of rats pretreated with verapamil was markedly increased as compared to rats treated with alloxan alone.