Coherent Picture on the Pure Spin Transport between Ag/Bi and Ferromagnets

In a joint effort of both experiments and first-principles calculations, we resolve a hotly debated controversy and provide a coherent picture on the pure spin transport between Ag/Bi and ferromagnets. We demonstrate a strong inverse Rashba-Edelstein effect (IREE) at the interface in between Ag/Bi with a ferromagnetic metal (FM) but not with a ferromagnetic insulator. This is in sharp contrast to the previously claimed IREE at Ag/Bi interface or inverse spin Hall effect dominated spin transport. A more than one order of magnitude modulation of IREE signal is realized for different Ag/Bi-FM interfaces, casting strong tunability and a new direction for searching efficient spintronics materials.

[Clinical effect of nasal endoscope combined with supporting laryngoscope surgery in the treatment of polyps of vocal cord and its influence on voice function of patients]

Objective:To explore the clinical value of nasal endoscope combined with supporting laryngoscope surgery in the treatment of polyps of vocal cord. Method:Ninety-four patients with vocal cord polyps were randomly divided into the control group (47 cases) and the observation group (47 cases). The patients in the control group were treated with simply supporting laryngoscope surgery while the patients in the observation group were treated with nasal endoscope combined with supporting laryngoscope. The therapeutic effects, voice function changes before and after operation, complications and recurrence of the two groups were observed. Result:The total effective rate was 93.62% in the observation group, compared to 78.72% in the control group, the difference was statistically significant (P<0.05). The incidence of postoperative complications in the observation group was 8.51%, compared with 25.53% in the control group, the difference was statistically significant (P<0.05). Six months after operation, there was no recurrence in the observation group, but the recurrence rate in the control group was 4.26%. There was no significant difference between the two groups (P>0.05). 12 months after operation, the recurrence rate of the observation group was 2.13%, compared with 14.89% of the control group, the difference was statistically significant (P<0.05). Conclusion:Nasal endoscope combined with supporting laryngoscope for vocal cord polyps has a definite effect and can significantly improve the voice function of patients with high safety and low recurrence rate, which is worthy of promotion..

[Relationship between endometrial thickness and pregnancy outcomes based on frozen-thawed embryo transfer cycles]

Objective: To explore the relationship between endometrial thickness and clinical pregnancy outcomes in frozen-thawed embryo transfer cycles. Methods: A prospective study was performed for 1 475 frozen-thawed embryo transfer cycles at Peking University People's Hospital from January 2014 to December 2015. The patients were divided into different groups according to endometrial thickness of ovulation day in natural menstrual cycles or endometrial transformation day in hormone replacement cycles;patients with thin endometrium were enndometrial thickness ≤6 mm. Then the clinical pregnancy outcomes including clinical pregnancy rate, embryo implantation rate, abortion rate, multiple birth rate and live birth rate were analyzed. Results: In all, 1 475 frozen-thawed embryo transfer cycles were analyzed. The mean age of patients was (32.5±3.9) years old and mean endometrial thickness was (9.2±1.9) mm, and mean number of embryos was 2.03±0.37. The study included 518 (35.1%) natural menstrual cycles and 957 (64.9%) hormone replacement cycles. The number of embryo-transfer cycles and blastocyst-transfer cycles were respectively 700 (47.5%) and 775 (52.5%) . The overall clinical pregnancy rate, embryo implantation rate, abortion rate, multiple birth rate and live birth rate were 54.4%, 35.7%, 23.3%, 24.1%, 43.9%, respectively. The ectopic pregnancy rate in the study was 0.6%. In patients with thin endometrium,there were significant differences in 2 pronucleus count (P=0.016) and available embryo count (P=0.024) between cycles that resulted in pregnancy and those that did not;besides, the use of sildenafil and growth hormone did not improve pregnancy outcomes in patients with thin endometrium (P=0.183, P=0.400) . The clinical pregnancy rate, embryo implantation rate and live birth rate of embryo-transfer and blastocyst-transfer were similar in patients with thin endometrium (all P>0.05) . Conclusions: Patients with thin endometrium have poor pregnancy outcomes. The clinical pregnancy rate, embryo implantation rate and live birth rate of embryo-transfer and blastocyst-transfer are similar in patients with thin endometrium. Compared thin endometrium and non-thin endometrium patients, the clinical pregnancy rate and live birth rate of blastocysts have more substantial decline than those of embryos. Improving the quality of embryo could improve the pregnancy outcome of patients with thin endometrium. Sildenafil and growth hormone could not improve pregnancy outcome in patients with thin endometrium.

Antiferromagnetic Order in Epitaxial FeSe Films on SrTiO_{3}

Single monolayer FeSe film grown on a Nb-doped SrTiO_{3}(001) substrate shows the highest superconducting transition temperature (T_{C}∼100  K) among the iron-based superconductors (iron pnictides), while the T_{C} value of bulk FeSe is only ∼8  K. Although bulk FeSe does not show antiferromagnetic order, calculations suggest that the parent FeSe/SrTiO_{3} films are antiferromagnetic. Experimentally, because of a lack of a direct probe, the magnetic state of FeSe/SrTiO_{3} films remains mysterious. Here, we report direct evidence of antiferromagnetic order in the parent FeSe/SrTiO_{3} films by the magnetic exchange bias effect measurements. The magnetic blocking temperature is ∼140  K for a single monolayer film. The antiferromagnetic order disappears after electron doping.

Unidirectional Spin-Wave-Propagation-Induced Seebeck Voltage in a PEDOT:PSS/YIG Bilayer

We clarify the physical origin of the dc voltage generation in a bilayer of a conducting polymer film and a micrometer-thick magnetic insulator Y_{3}Fe_{5}O_{12} (YIG) film under ferromagnetic resonance and/or spin wave excitation conditions. The previous attributed mechanism, the inverse spin Hall effect in the polymer [Nat. Mater. 12, 622 (2013)NMAACR1476-112210.1038/nmat3634], is excluded by two control experiments. We find an in-plane temperature gradient in YIG which has the same angular dependence with the generated voltage. Both vanish when the YIG thickness is reduced to a few nanometers. Thus, we argue that the dc voltage is governed by the Seebeck effect in the polymer, where the temperature gradient is created by the nonreciprocal magnetostatic surface spin wave propagation in YIG.

Exchange-Dominated Pure Spin Current Transport in Alq3 Molecules

We address the controversy over the spin transport mechanism in Alq3 utilizing spin pumping in the Y3Fe5O12/Alq3/Pd system. An unusual angular dependence of the inverse spin Hall effect is found. It, however, disappears when the microwave magnetic field is fully in the sample plane, excluding the presence of the Hanle effect. Together with the quantitative temperature-dependent measurements, these results provide compelling evidence that the pure spin current transport in Alq3 is dominated by the exchange-mediated mechanism.

Spectroscopic study of Gd nanostructures quantum confined in Fe corrals

Low dimensional nanostructures have attracted attention due to their rich physical properties and potential applications. The essential factor for their functionality is their electronic properties, which can be modified by quantum confinement. Here the electronic states of Gd atom trapped in open Fe corrals on Ag(111) were studied via scanning tunneling spectroscopy. A single spectroscopic peak above the Fermi level is observed after Gd adatoms are trapped inside Fe corrals, while two peaks appear in empty corrals. The single peak position is close to the higher energy peak of the empty corrals. These findings, attributed to quantum confinement of the corrals and Gd structures trapped inside, are supported by tight-binding calculations. This demonstrates and provides insights into atom trapping in open corrals of various diameters, giving an alternative approach to modify the properties of nano-objects.

Creating an artificial two-dimensional Skyrmion crystal by nanopatterning

A Skyrmion crystal typically arises from helical spin structures induced by the Dzyaloshinskii-Moriya interaction. Experimentally its physical exploration has been impeded because it is a rarity and is found only within a narrow temperature and magnetic field range. We present a method for the assembly of a two-dimensional Skyrmion crystal based upon a combination of a perpendicularly magnetized film and nanopatterned arrays of magnetic vortices that are geometrically confined within nanodisks. The practical feasibility of the method is validated by micromagnetic simulations and computed Skyrmion number per unit cell. We also quantify a wide range in temperature and field strength over which the Skyrmion crystal can be stabilized without the need for any intrinsic Dzyaloshinskii-Moriya interactions, which otherwise is needed to underpin the arrangement as is the case in the very few known Skyrmion crystal cases. Thus, our suggested scheme involves a qualitative breakthrough that comes with a substantial quantitative advance.

Biologic effect and immunoisolating behavior of BMP-2 gene-transfected bone marrow-derived mesenchymal stem cells in APA microcapsules

We investigated the encapsulation of BMP-2 gene-modified mesenchymal stem cells (MSCs) in alginate-poly-L-lysine (APA) microcapsules for the persistent delivery of bone morphogenic protein-2 (BMP-2) to induce bone formation. An electrostatic droplet generator was employed to produce APA microcapsules containing encapsulated beta-gal or BMP-2 gene-transfected bone marrow-derived MSCs. We found that X-gal staining was still positive 28 days after encapsulation. Encapsulated BMP-2 gene-transfected cells were capable of constitutive delivery of BMP-2 proteins for at least 30 days. The encapsulated BMP-2 gene-transfected MSCs or the encapsulated non-gene transfer MSCs (control group) were cocultured with the undifferentiated MSCs. The gene products from the encapsulated BMP-2 cells could induce the undifferentiated MSCs to become osteoblasts that had higher alkaline phosphatase (ALP) activity than those in the control group (p<0.05). The APA microcapsules could inhibit the permeation of fluorescein isothiocyanate-conjuncted immunoglobulin G. Mixed lymphocyte reaction also indicates that the APA microcapsules could prevent the encapsulated BMP-2 gene-transfected MSCs from initiating the cellular immune response. These results demonstrated that the nonautologous BMP-2 gene-transfected stem cells are of potential utility for enhancement of bone repair and bone regeneration in vivo.

Magnetic bistability of Co nanodots

Size-dependent magnetic single-domain versus vortex state stability of Co/Ru(0001) nanodots is explored with spin-polarized low-energy electron microscopy, analytical modeling, and micromagnetic simulations. We show that both single-domain and vortex states can be stabilized in a broad region near the phase boundary. The calculated width of the bistability region and temperature dependent heights of the energy barriers between both states agree well with our experimental findings.

Absence of zero-bias anomaly in spin-polarized vacuum tunneling in Co(0001)

In a joint experimental and theoretical study, we investigate the bias-voltage dependence of the tunnel magnetoresistance (TMR) through a vacuum barrier. The TMR observed by spin-polarized scanning tunneling microscopy between an amorphous magnetic tip and a Co(0001) sample is almost independent of the bias voltage at large tip-sample separations. Whereas qualitative understanding is achieved by means of the electronic surface structure of Co, the experimental findings are compared quantitatively with bias-voltage dependent first-principles calculations for ballistic tunneling. At small tip-sample separations, a pronounced minimum in the experimental TMR was found at +200 mV bias.

Essential role for caspase-8 in transcription-independent apoptosis triggered by p53

p53's dual regulation of arrest versus apoptosis may underlie tumor-selective effects of anti-cancer therapy. p53's apoptotic effect has been suggested to involve both transcription-dependent and -independent mechanisms. It is shown here that caspase-8 is activated early in cells undergoing p53-mediated apoptosis and in S100 cell-free extracts that recapitulate transcription-independent apoptosis. Depletion or inactivation of caspase-8 either in cells or cell-free extracts completely prevents this transcription-independent apoptosis and significantly attenuates overall death induced by wild-type p53. Importantly, caspase-8 activation appears to be independent of FADD, and caspase-8 is found in a novel 600-kDa complex following p53 activation. These findings highlight the roles of both transcription-dependent and -independent apoptosis by p53 and identify an essential role for caspase-8 in the transcription-independent pathway.

Oncogene-dependent regulation of caspase activation by p53 protein in a cell-free system

The mechanism by which p53 modulates apoptosis in cancer therapy is incompletely understood. Here, cell-free extracts from irradiated tumor cells are described in which endogenous p53 protein is shown to participate in caspase activation. This apoptotic activity is also oncogene-dependent, but independent of transcription in general or the presence of Bax or cytochrome c. A general use for this system is as a cell-free screen for apoptosis modulators. In this way, profound effects of protein kinase A were identified and corroborated in vivo by the protection conferred by cAMP against diverse triggers of p53-dependent apoptosis. This system provides direct biochemical evidence that p53 protein can transduce apoptotic signals through protein-protein interactions and reveals a modulator kinase pathway capable of regulating p53-dependent caspase activation.

Mechanisms of p53-mediated apoptosis

p53-mediated apoptosis of cells with DNA damage or oncogene overexpression is a major mechanism for its function as a tumor suppressor. Both transcriptionally dependent and transcriptionally independent activities of p53 can play a role in mediating cell death. It appears that p53 can induce apoptosis by multiple pathways in a manner which is regulated in a cell type and signal-specific fashion. Understanding the biochemical mechanisms of p53-dependent apoptosis holds a promise of manipulating these pathways in cancer therapy.

Lineage-specific signaling in melanocytes. C-kit stimulation recruits p300/CBP to microphthalmia

During melanocyte development, the cytokine Steel factor activates its receptor c-Kit, initiating a signal transduction cascade, which is vital for lineage determination via unknown downstream nuclear targets. c-Kit has recently been found to trigger mitogen-activated protein kinase-mediated phosphorylation of Microphthalmia (Mi), a lineage-restricted transcription factor, which, like Steel factor and c-Kit, is essential for melanocyte development. This cascade results in increased Mi-dependent transcriptional reporter activity. Here we examine the mechanism by which Mi is activated by this pathway. Phosphorylation does not significantly alter Mi's nuclear localization, DNA binding, or dimerization. However, the transcriptional coactivator p300/CBP selectively associates with mitogen-activated protein kinase-phosphorylated Mi, even under conditions in which non-MAPK phospho-Mi is more abundant. Moreover, p300/CBP coactivates Mi transcriptional activity in a manner dependent upon this phosphorylation. Mi thus joins CREB as a transcription factor whose signal-responsive phosphorylation regulates coactivator recruitment, in this case modulating lineage development in melanocytes.

Alleviation of histone H1-mediated transcriptional repression and chromatin compaction by the acidic activation region in chromosomal protein HMG-14

Histone H1 promotes the generation of a condensed, transcriptionally inactive, higher-order chromatin structure. Consequently, histone H1 activity must be antagonized in order to convert chromatin to a transcriptionally competent, more extended structure. Using simian virus 40 minichromosomes as a model system, we now demonstrate that the nonhistone chromosomal protein HMG-14, which is known to preferentially associate with active chromatin, completely alleviates histone H1-mediated inhibition of transcription by RNA polymerase II. HMG-14 also partially disrupts histone H1-dependent compaction of chromatin. Both the transcriptional enhancement and chromatin-unfolding activities of HMG-14 are mediated through its acidic, C-terminal region. Strikingly, transcriptional and structural activities of HMG-14 are maintained upon replacement of the C-terminal fragment by acidic regions from either GAL4 or HMG-2. These data support the model that the acidic C terminus of HMG-14 is involved in unfolding higher-order chromatin structure to facilitate transcriptional activation of mammalian genes.

[Determination of alkaloids and comparison of the acute toxicity of differently processed products of the seeds of Strychnos nux-vomica L]

This paper deals with the extraction, determination and identification of the alkaloids in differently processed products of the seeds of Strychnos nux-vomica. The relationship between processing methods and toxicitys is discussed according to the comparison of acute toxicity.

Stimulation of RNA polymerase II elongation by chromosomal protein HMG-14

The high-mobility group protein 14 (HMG-14) is a non-histone chromosomal protein that is preferentially associated with transcriptionally active chromatin. To assess the effect of HMG-14 on transcription by RNA polymerase II, in vivo-assembled chromatin with elevated amounts of HMG-14 was obtained. Here it is shown that HMG-14 enhanced transcription on chromatin templates but not on DNA templates. This protein stimulated the rate of elongation by RNA polymerase II but not the level of initiation of transcription. These findings suggest that the association of HMG-14 with nucleosomes is part of the cellular process involved in the generation of transcriptionally active chromatin.

The molar ratio of sigma 73 to core polymerase in the obligate intracellular bacterium, Rickettsia prowazekii

In the obligate intracellular parasitic bacterium, Rickettsia prowazekii, the molar ratio of sigma 73 to core RNA polymerase, that is, the degree of saturation of the core polymerase by the catalytically active sigma factor, was very low. This ratio was determined from the radioactivity in rickettsial RNA polymerase immunoprecipitated from crude extracts of infected L929 cells in which the parasite was exponentially growing. If we assume that, as is true for the sigma subunit, in R. prowazekii and Escherichia coli the beta', and beta subunits of the RNA polymerase have similar methionine and cysteine contents (the radiolabelled amino acids), the molar ratio of sigma 73 to core polymerase in R. prowazekii would be 0.1. This is in striking contrast to E. coli where the ratio is typically 0.4. It remains to be established whether this low sigma saturation results in a limitation of active RNA polymerase in R. prowazekii and contributes to its slow growth.

Characterization of the DNA-melting function of the Rickettsia prowazekii RNA polymerase

In vitro specific transcription by the Rickettsia prowazekii RNA polymerase was investigated. The purified rickettsial RNA polymerase, in striking contrast to that of Escherichia coli, could specifically transcribe two R. prowazekii genes (ATP/ADP translocase and citrate synthase genes) and one E. coli gene (RNA-I) on negative supercoiled plasmids but not the same genes on linear plasmids. Following the specific binding of the rickettsial RNA polymerase to the translocase gene promoter on a linear plasmid, there was no detectable open complex formation. Both the E. coli and the R. prowazekii RNA polymerases worked well when poly(dA-dT).poly(dA-dT) or poly(dI-dC).poly-(dI-dC) was used as template for generalized transcription. However, the rickettsial RNA polymerase, in contrast to the E. coli enzyme, had little activity on poly(dG-dC).poly(dG-dC), a template with a larger number of hydrogen bonds. These data indicate that the rickettsial RNA polymerase is weak, at least relative to E. coli, in the function required for the opening of DNA duplex. It appears that this operation in R. prowazekii is aided by the negative supercoiling and the high 72% AT composition of the rickettsial genome.

Purification and partial characterization of the DNA-dependent RNA polymerase from Rickettsia prowazekii

The DNA-dependent RNA polymerase was purified from Rickettsia prowazekii, an obligate intracellular bacterial parasite. Because of limitation of available rickettsiae, the classical methods for isolation of the enzyme from other procaryotes were modified to purify RNA polymerase from small quantities of cells (25 mg of protein). The subunit composition of the rickettsial RNA polymerase was typical of a eubacterial RNA polymerase. R. prowazekii had beta' (148,000 daltons), beta (142,000 daltons), sigma (85,000 daltons), and alpha (34,500 daltons) subunits as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The appropriate subunits of the rickettsial RNA polymerase bound to polyclonal antisera against Escherichia coli core polymerase and E. coli sigma 70 subunit in Western blots (immunoblots). The enzyme activity was dependent on all four ribonucleoside triphosphates, Mg2+, and a DNA template. Optimal activity occurred in the presence of 10 mM MgCl2 and 50 mM NaCl. Interestingly, in striking contrast to E. coli, approximately 74% of the rickettsial RNA polymerase activity was associated with the rickettsial cell membrane at a low salt concentration (50 mM NaCl) and dissociated from the membrane at a high salt concentration (600 mM NaCl).

Protective immunity induced in mice by detoxified salmonella lipopolysaccharide

C3H/HeNMTV mice were immunised intraperitoneally (i.p.) with lipopolysaccharide (LPS) or detoxified LPS (D-LPS) derived from Salmonella typhimurium strain SR-11. In both cases, effective protection was achieved against a challenge dose of greater than 2 x 10(2) LD50 of the same organism given by i.p. injection. However, by comparison with LPS, approximately 6- to 10-fold more of D-LPS by weight was needed to protect mice to an equivalent degree. Histopathological studies showed that the initial lesions in infected mice protected with either LPS or D-LPS were composed of self-limiting abscesses which transformed into granulomas as the animals recovered. It is suggested that D-LPS may be modified to become a highly effective, non-toxic salmonella vaccine.