112 research outputs found
Interaction of Phonons and Dirac Fermions on the Surface of Bi2Se3: A Strong Kohn Anomaly
We report the first measurements of phonon dispersion curves on the (001)
surface of the strong three-dimensional topological insulator Bi2Se3. The
surface phonon measurements were carried out with the aid of coherent helium
beam surface scattering techniques. The results reveal a prominent signature of
the exotic metallic Dirac fermion quasi-particles, including a strong Kohn
anomaly. The signature is manifest in a low energy isotropic convex dispersive
surface phonon branch with a frequency maximum of 1.8 THz, and having a
V-shaped minimum at approximately 2kF that defines the Kohn anomaly.
Theoretical analysis attributes this dispersive profile to the renormalization
of the surface phonon excitations by the surface Dirac fermions. The
contribution of the Dirac fermions to this renormalization is derived in terms
of a Coulomb-type perturbation model
Womenβs Health Care Utilization among Harder-to-Reach HIV-Infected Women ever on Antiretroviral Therapy in British Columbia
Background. HIV-infected women are disproportionately burdened by gynaecological complications, psychological disorders, and certain sexually transmitted infections that may not be adequately addressed by HIV-specific care. We estimate the prevalence and covariates of womenβs health care (WHC) utilization among harder-to-reach, treatment-experienced HIV-infected women in British Columbia (BC), Canada. Methods. We used survey data from 231 HIV-infected, treatment-experienced women enrolled in the Longitudinal Investigations into Supportive and Ancillary Health Services (LISA) study, which recruited harder-to-reach populations, including aboriginal people and individuals using injection drugs. Independent covariates of interest included sociodemographic, psychosocial, behavioural, individual health status, structural factors, and HIV clinical variables. Logistic regression was used to generate adjusted estimates of associations between use of WHC and covariates of interest. Results. Overall, 77% of women reported regularly utilizing WHC. WHC utilization varied significantly by region of residence (P value <0.01). In addition, women with lower annual income (AOR (95% CI) = 0.14 (0.04β0.54)), who used illicit drugs (AOR (95% CI) = 0.42 (0.19β0.92)) and who had lower provider trust (AOR (95% CI) = 0.97 (0.95β0.99)), were significantly less likely to report using WHC. Conclusion. A health service gap exists along geographical and social axes for harder-to-reach HIV-infected women in BC. Women-centered WHC and HIV-specific care should be streamlined and integrated to better address womenβs holistic health
Tissue-Engineered Trachea Consisting of Electrospun Patterned sc-PLA/GO-g-IL Fibrous Membranes with Antibacterial Property and 3D-Printed Skeletons with Elasticity
In this study, a tissue-engineered trachea, consisting of multilevel structural electrospun polylactide (PLA) membranes enveloping 3D-printed thermoplastic polyurethane (TPU) skeletons, was developed to create a mechanically robust, antibacterial and bioresorbable graft for the tracheal reconstruction. The study design incorporated two distinct uses of stereocomplex PLA: patterned electrospun fibers to enhance tissue integration compared to the random layered fibers, meanwhile possessing good antibacterial property; and 3D-printed TPU scaffold with elasticity to provide external support and protection. Herein, ionic liquid (IL)-functioned graphene oxide (GO) was synthesized and presented enhanced mechanical and hydrophilicity properties. More interesting, antibacterial activity of the GO-g-IL modified PLA membranes were proved by Escherichia coli and Staphylococcus aureus, showing superior antibacterial effect compared to single GO or IL. The synergistic antibacterial effect could be related to that GO break cytomembrane of bacteria by its extremely sharp edges, while IL works by electrostatic interaction between its cationic structures and electronegative phosphate groups of bacteria membranes, leading to the loss of cell electrolyte and cell death. Hence, after L929 fibroblast cells were seeded on patterned fibrous membranes with phenotypic shape, further effective cell infiltration, cell proliferation and attachment were observed. In addition, the tissue-engineered trachea scaffolds were implanted into rabbit models. The in vivo result confirmed that the scaffolds with patterned membranes manifested favorable biocompatibility and promoted tissue regeneration
ΠΠΎΠ»ΡΠΌΠΎΡΡΡΠ·ΠΌ ΠΊΠ°ΡΠΎΠΊ ΠΏΠΎΡΠΎΠ΄ΠΈ shaoxing Π·Π° ΠΌΡΠΊΡΠΎΡΠ°ΡΠ΅Π»ΡΡΠ½ΠΈΠΌΠΈ Π»ΠΎΠΊΡΡΠ°ΠΌΠΈ
Microsatellite markers are now been widely used for the detection and description of micropopulation processes occurring in the populations of domestic animals for the effects of various factors of breeding pressure. Microsatellite loci distributed throughout eukaryotic genomes, making them the preferred genetic marker for high resolution genetic mapping. In recent years, rapid advances have been made in the development of molecular genetic maps. High-density linkage maps are now available for many farm animals, such as cattle, pigs, and goats. In contrast, mapping studies in avian species are much less advanced except in the chicken. According to FAO about 70% of ducks are bred in China. This country is a leader in growing ducks. The Shaoxing breed is one of the three major duck breeds in China. Ducks of this breed are characterized by high performance. According to the Bureau of Product Quality, the age of maturity (the beginning of egg laying) in these birds occurs at 130β140 days. The characteristics of the Shaoxing breed include the fact that the peak period of laying eggs lasts from eight to ten months. On average, one duck in 500 days gives from 290 to 310 eggs, which is one of the highest rates for egg breeds. That is why the purpose of our study was the microsatellite analysis of two populations of Shaoxing breed with 9 locuses was conducted. The selection of birds for the study were carried out on a duck farms in Zhejiang Generation Biological Science and Technology Co., Ltd. and Zhuji Guowei Poultry Development Co, Ltd., and at the laboratory of the Jjejiang Academy of Sciences Institute. Samples collection and DNA preparation: Venous blood samples were collected from 480 ducks (240 ducks of population I and 240 ducks of population II of the Shaoxing breeds) of both populations into 3 ml tubes containing EDTA as anticoagulant agent. In total of 9 investigated loci in the Shaoxing breed population, only one locus was monomorphic (SMO10). The number of different alleles (Na) for each polymorphic locus ranged from 2 (SMO12) to 13 (APL79, CMO11) in population I and from 2 (APL78, SMO12) to 7 (APL79) in population II. On average, one locus had 5.889 alleles in population I and 3.889 of alleles in the population II. The effective number of alleles (NΠ΅) was 1.735 in population I and 1.599 in population II. The number of alleles and the expected heterozygosity (Hexp) values can provide important information for the discrimination of individuals and breeds. The index of expected heterozygosity in population I was 0.336 and 0.307 in population II. The information index (I) was 0,702 in population I and 0,576 in population II. For each population was found private alleles, in population I 6 alleles and in population II just 4 alleles. The results show high level of polymorphism of the studied populations of ducks. The obtained results can be used in the creation of new lines of ducks.Π£ ΡΡΠ°ΡΡΡ Π½Π°Π²Π΅Π΄Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΈ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Ρ Π³Π΅Π½Π΅ΡΠΈΡΠ½ΠΎΡ ΡΡΡΡΠΊΡΡΡΠΈ Π΄Π²ΠΎΡ
ΠΏΠΎΠΏΡΠ»ΡΡΡΠΉ ΠΊΠ°ΡΠΎΠΊ ΠΏΠΎΡΠΎΠ΄ΠΈ ΡΠ°ΠΎΡΡΠ½Ρ Π·Π° Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½Ρ Π΄Π΅Π²βΡΡΠΈ ΠΌΡΠΊΡΠΎΡΠ°ΡΠ΅Π»ΡΡΠ½ΠΈΡ
Π»ΠΎΠΊΡΡΡΠ². ΠΡΠΈΡΡ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΡΠ²Π°Π»ΠΈ Π½Π° ΠΊΠ°ΡΠΈΠ½ΠΈΡ
ΡΠ΅ΡΠΌΠ°Ρ
ΠΊΠΎΠΌΠΏΠ°Π½ΡΠΉ Zhejiang Generation Biological Science and Technology Co., Ltd. ΡΠ° Zhuji Guowei Poultry Development Co, Ltd. Π·Π° ΠΏΡΠ΄ΡΡΠΈΠΌΠΊΠΈ Π»Π°Π±ΠΎΡΠ°ΡΠΎΡΡΡ Poultry Genetics Laboratory of the Zhejiang Academy of Sciences (Zhejiang Province, PRC). ΠΡΠ»ΠΎ Π²ΡΡΠ°Π½ΠΎΠ²Π»Π΅Π½ΠΎ, ΡΠΎ ΡΠ΅ΡΠ΅Π΄Π½Ρ ΡΠΈΡΠ»ΠΎ Π΅ΡΠ΅ΠΊΡΠΈΠ²Π½ΠΈΡ
Π°Π»Π΅Π»ΡΠ² (Ne) Π½Π° Π»ΠΎΠΊΡΡ Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π ΡΠΊΠ»Π°Π΄Π°Π»ΠΎ 1,735, Π° Π΄Π»Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ ΠΠ β 1,599. ΠΠΎΠΊΠ°Π·Π½ΠΈΠΊΠΈ ΡΠ½ΡΠΎΡΠΌΠ°ΡΡΠΉΠ½ΠΎΠ³ΠΎ ΡΠ½Π΄Π΅ΠΊΡΡ ΡΡΠ°Π½ΠΎΠ²ΠΈΠ»ΠΈ 0,702 (ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π) ΡΠ° 0,576 (ΠΏΠΎΠΏΡΠ»ΡΡΡΡ ΠΠ). Π€Π°ΠΊΡΠΈΡΠ½Π° Π³Π΅ΡΠ΅ΡΠΎΠ·ΠΈΠ³ΠΎΡΠ½ΡΡΡΡ Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π Π±ΡΠ»Π° 0,298, Π° Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ ΠΠ β 0,269. Π£ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ Π½Π°ΡΠΎΠ³ΠΎ Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½Π½Ρ Π΄Π»Ρ ΠΊΠΎΠΆΠ½ΠΎΡ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π±ΡΠ»ΠΈ Π²ΠΈΡΠ²Π»Π΅Π½Ρ ΠΏΡΠΈΠ²Π°ΡΠ½Ρ Π°Π»Π΅Π»Ρ. Π 9 Π΄ΠΎΡΠ»ΡΠ΄ΠΆΠ΅Π½ΠΈΡ
Π»ΠΎΠΊΡΡΡΠ², Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π Π±ΡΠ»ΠΎ Π²ΠΈΡΠ²Π»Π΅Π½ΠΎ 6 ΠΏΡΠΈΠ²Π°ΡΠ½ΠΈΡ
Π°Π»Π΅Π»ΡΠ², Π² ΡΠΎΠΉ ΡΠ°Ρ, ΠΊΠΎΠ»ΠΈ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ ΠΠ ΠΌΠ°Π»Π° Π»ΠΈΡΠ΅ 4 Π»ΠΎΠΊΡΡΠΈ. ΠΠ°Π³Π°Π»ΠΎΠΌ Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π Π²ΠΈΡΠ²Π»Π΅Π½ΠΎ 23 ΠΏΡΠΈΠ²Π°ΡΠ½ΠΈΡ
Π°Π»Π΅Π»ΡΠ², Π° Ρ ΠΏΠΎΠΏΡΠ»ΡΡΡΡ ΠΠ β 5. ΠΠ°ΠΉΠ±ΡΠ»ΡΡΠ° ΠΊΡΠ»ΡΠΊΡΡΡΡ ΠΏΡΠΈΠ²Π°ΡΠ½ΠΈΡ
Π°Π»Π΅Π»ΡΠ² Π±ΡΠ»Π° Π² Π»ΠΎΠΊΡΡΡ CMO11 (9), Π° Π½Π°ΠΉΠΌΠ΅Π½ΡΠ° β 1 Π°Π»Π΅Π»Ρ Ρ Π»ΠΎΠΊΡΡΡ SMO7 ΡΠ° SMO10 Π² ΠΏΠΎΠΏΡΠ»ΡΡΡΡ Π. ΠΠΎΠΏΡΠ»ΡΡΡΡ ΠΠ Π±ΡΠ»Π° Π±ΡΠ΄Π½ΡΡΠ° Π½Π° ΠΏΡΠΈΠ²Π°ΡΠ½Ρ Π°Π»Π΅Π»Ρ, ΡΠ°ΠΊ Ρ Π»ΠΎΠΊΡΡΡ APL79 Π±ΡΠ»ΠΎ 2 ΡΠ° ΠΏΠΎ 1 Ρ CMO11, SMO7, SMO10. ΠΡΡΠΈΠΌΠ°Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΈ ΡΠ²ΡΠ΄ΡΠ°ΡΡ ΠΏΡΠΎ Π²ΠΈΡΠΎΠΊΠΈΠΉ ΡΡΠ²Π΅Π½Ρ Π²Π½ΡΡΡΡΡΠ½ΡΠΎΠΏΠΎΡΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΏΠΎΠ»ΡΠΌΠΎΡΡΡΠ·ΠΌΡ ΡΠ°ΠΎΡΡΠ½Ρ, ΡΠΎ Π΄ΠΎΠ·Π²ΠΎΠ»ΡΡ ΡΠΎΠ·ΡΠΎΠ±ΠΊΡ ΡΡΡΠ°ΡΠ΅Π³ΡΠΉ Π·Π±Π΅ΡΠ΅ΠΆΠ΅Π½Π½Ρ ΡΠ° Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½Ρ Π³Π΅Π½Π΅ΡΠΈΡΠ½ΠΈΡ
ΡΠ΅ΡΡΡΡΡΠ² ΠΊΠ°ΡΠΊΠΈ Π·Π° Π²ΠΈΠΊΠΎΡΠΈΡΡΠ°Π½Π½Ρ Π°Π½Π°Π»ΡΠ·Ρ ΠΏΠΎΠ»ΡΠΌΠΎΡΡΠ½ΠΈΡ
Π»ΠΎΠΊΡΡΡΠ² ΠΌΡΠΊΡΠΎΡΠ°ΡΠ΅Π»ΡΡΡ
Dramatic plasmon response to the charge-density-wave gap development in 1T-TiSe2
1TβTiSe2 is one of the most studied charge density wave (CDW) systems, not only because of its peculiar properties related to the CDW transition, but also due to its status as a promising candidate of exciton insulator signaled by the proposed plasmon softening at the CDW wave vector. Using high-resolution electron energy loss spectroscopy, we report a systematic study of the temperature-dependent plasmon behaviors of 1TβTiSe2. We unambiguously resolve the plasmon from phonon modes, revealing the existence of Landau damping to the plasmon at finite momentums, which does not support the plasmon softening picture for exciton condensation. Moreover, we discover that the plasmon lifetime at zero momentum responds dramatically to the band gap evolution associated with the CDW transition. The interband transitions near the Fermi energy in the normal phase are demonstrated to serve as a strong damping channel of plasmons, while such a channel in the CDW phase is suppressed due to the CDW gap opening, which results in the dramatic tunability of the plasmon in semimetals or small-gap semiconductors.This work was supported by the National Key R&D Program of China (No.2021YFA1400200 and No.2017YFA0303600), the National Natural Science Foundation of China (No.11874404andNo.11974399), and the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDB33000000). V.M.S. acknowledges financial support by Grant No .PID2019105488GB-I00 funded by MCIN/AEI/10.13039/501100011033/. X.Z. was partially supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences.Peer reviewe
The effect of graphene network formation on the electrical, mechanical, and multifunctional properties of graphene/epoxy nanocomposites
Parathyroid Hormone versus Bisphosphonate Treatment on Bone Mineral Density in Osteoporosis Therapy: A Meta-Analysis of Randomized Controlled Trials
BACKGROUND: Bisphosphonates and parathyroid hormone (PTH) represent the antiresorptive and anabolic classes of drugs for osteoporosis treatment. Bone mineral density (BMD) is an essential parameter for the evaluation of anti-osteoporotic drugs. The aim of this study was to evaluate the effects of PTH versus bisphosphonates on BMD for the treatment of osteoporosis. METHODS/PRINCIPAL FINDINGS: We performed a literature search to identify studies that investigated the effects of PTH versus bisphosphonates treatment on BMD. A total of 7 articles were included in this study, representing data on 944 subjects. The pooled data showed that the percent change of increased BMD in the spine is higher with PTH compared to bisphosphonates (WMDβ=β5.90, 95% CI: 3.69-8.10, p<0.01,). In the hip, high dose (40 Β΅g) PTH (1-34) showed significantly higher increments of BMD compared to alendronate (femoral neck: WMDβ=β5.67, 95% CI: 3.47-7.87, p<0.01; total hip: WMDβ=β2.40, 95%CI: 0.49-4.31, p<0.05). PTH treatment has yielded significantly higher increments than bisphosphonates with a duration of over 12 months (femoral neck: WMDβ=β5.67, 95% CI: 3.47-7.86, p<0.01; total hip: WMDβ=β2.40, 95% CI: 0.49-4.31, P<0.05) and significantly lower increments at 12 months (femoral neck: WMDβ=β-1.05, 95% CI: -2.26-0.16, p<0.01; total hip: WMD: -1.69, 95% CI: -3.05-0.34, p<0.05). In the distal radius, a reduction in BMD was significant between PTH and alendronate treatment. (WMDβ=β-3.68, 95% CI: -5.57-1.79, p<0.01). DISCUSSION: Our results demonstrated that PTH significantly increased lumbar spine BMD as compared to treatment with bisphosphonates and PTH treatment induced duration- and dose-dependent increases in hip BMD as compared to bisphosphonates treatment. This study has also disclosed that for the distal radius, BMD was significantly lower from PTH treatment than alendronate treatment
Human Fetal Liver Stromal Cells That Overexpress bFGF Support Growth and Maintenance of Human Embryonic Stem Cells
In guiding hES cell technology toward the clinic, one key issue to be addressed is to culture and maintain hES cells much more safely and economically in large scale. In order to avoid using mouse embryonic fibroblasts (MEFs) we isolated human fetal liver stromal cells (hFLSCs) from 14 weeks human fetal liver as new human feeder cells. hFLSCs feeders could maintain hES cells for 15 passages (about 100 days). Basic fibroblast growth factor (bFGF) is known to play an important role in promoting self-renewal of human embryonic stem (hES) cells. So, we established transgenic hFLSCs that stably express bFGF by lentiviral vectors. These transgenic human feeder cells β bFGF-hFLSCs maintained the properties of H9 hES cells without supplementing with any exogenous growth factors. H9 hES cells culturing under these conditions maintained all hES cell features after prolonged culture, including the developmental potential to differentiate into representative tissues of all three embryonic germ layers, unlimited and undifferentiated proliferative ability, and maintenance of normal karyotype. Our results demonstrated that bFGF-hFLSCs feeder cells were central to establishing the signaling network among bFGF, insulin-like growth factor 2 (IGF-2), and transforming growth factor Ξ² (TGF-Ξ²), thereby providing the framework in which hES cells were instructed to self-renew or to differentiate. We also found that the conditioned medium of bFGF-hFLSCs could maintain the H9 hES cells under feeder-free conditions without supplementing with bFGF. Taken together, bFGF-hFLSCs had great potential as feeders for maintaining pluripotent hES cell lines more safely and economically
Comprehensive Dissection of PDGF-PDGFR Signaling Pathways in PDGFR Genetically Defined Cells
Despite the growing understanding of PDGF signaling, studies of PDGF function have encountered two major obstacles: the functional redundancy of PDGFRΞ± and PDGFRΞ² in vitro and their distinct roles in vivo. Here we used wild-type mouse embryonic fibroblasts (MEF), MEF null for either PDGFRΞ±, Ξ², or both to dissect PDGF-PDGFR signaling pathways. These four PDGFR genetically defined cells provided us a platform to study the relative contributions of the pathways triggered by the two PDGF receptors. They were treated with PDGF-BB and analyzed for differential gene expression, in vitro proliferation and differential response to pharmacological effects. No genes were differentially expressed in the double null cells, suggesting minimal receptor-independent signaling. Protean differentiation and proliferation pathways are commonly regulated by PDGFRΞ±, PDGFRΞ² and PDGFRΞ±/Ξ² while each receptor is also responsible for regulating unique signaling pathways. Furthermore, some signaling is solely modulated through heterodimeric PDGFRΞ±/Ξ²
Sonic Hedgehog Pathway Is Essential for Maintenance of Cancer Stem-Like Cells in Human Gastric Cancer
Abnormal activation of the Sonic hedgehog (SHH) pathway has been described in a wide variety of human cancers and in cancer stem cells (CSCs), however, the role of SHH pathway in gastric CSCs has not been reported. In this study, we investigated the possibility that abnormal activation of the SHH pathway maintained the characteristics of gastric CSCs. First, we identified cancer stem-like cells (CSLCs) from human gastric cancer cell lines (HGC-27, MGC-803 and MKN-45) using tumorsphere culture. Compared with adherent cells, the floating tumorsphere cells had more self-renewing capacity and chemoresistance. The cells expressing CSCs markers (CD44, CD24 and CD133) were also significantly more in tumorsphere cells than in adherent cells. More importantly, in vivo xenograft studies showed that tumors could be generated with 2Γ104 tumorsphere cells, which was 100-fold less than those required for tumors seeding by adherent cells. Next, RT-PCR and Western blot showed that the expression levels of Ptch and Gli1 (SHH pathway target genes) were significantly higher in tumorsphere cells than in adherent cells. The results of quantitative real-time PCR were similar to those of RT-PCR and Western blot. Further analysis revealed that SHH pathway blocked by cyclopamine or 5E1 caused a higher reduction in self-renewing capacity of HGC-27 tumorsphere cells than that of adherent cells. We also found that SHH pathway blocking strongly enhanced the efficacy of chemotherapeutic drugs in HGC-27 tumorsphere cells in vitro and in vivo but had no significant effect in adherent cells. Finally, we isolated the tumorspheres from gastric cancer specimen, these cells also had chemoresistance and tumorigenic capacity, and SHH pathway maintained the gastric CSLCs characteristics of tumorsphere cells from primary tumor samples. In conclusion, our data suggested that SHH pathway was essential for maintenance of CSLCs in human gastric cancer
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