549 research outputs found
Graphene-based spintronic components
A major challenge of spintronics is in generating, controlling and detecting
spin-polarized current. Manipulation of spin-polarized current, in particular,
is difficult. We demonstrate here, based on calculated transport properties of
graphene nanoribbons, that nearly +-100% spin-polarized current can be
generated in zigzag graphene nanoribbons (ZGNRs) and tuned by a source-drain
voltage in the bipolar spin diode, in addition to magnetic configurations of
the electrodes. This unusual transport property is attributed to the intrinsic
transmission selection rule of the spin subbands near the Fermi level in ZGNRs.
The simultaneous control of spin current by the bias voltage and the magnetic
configurations of the electrodes provides an opportunity to implement a whole
range of spintronics devices. We propose theoretical designs for a complete set
of basic spintronic devices, including bipolar spin diode, transistor and logic
gates, based on ZGNRs.Comment: 14 pages, 4 figure
Ethyl 6-(4-fluorophenyl)-4-hydroxy-2-oxo-4-trifluoromethyl-1,3-diazinane-5-carboxylate monohydrate
The asymmetric unit of the title compound, C14H14F4N2O4·H2O, contains two crystallographically independent organic molecules and two water molecules. The two 1,3-diazinane rings adopt a half-chair conformation and the dihedral angles between their mean planes and those of the benzene rings are 75.65 (4)° and 49.41 (3)° in the two molecules. The crystal structure is stabilized by intermolecular O—H⋯O and N—H⋯O hydrogen bonds
Adsorbate and defect effects on electronic and transport properties of gold nanotubes
First-principles calculations have been performed to study the effects of
adsorbates (CO molecules and O atoms) and defects on electronic structures and
transport properties of Au nanotubes (Au(5, 3) and Au(5, 5)). For CO
adsorption, various adsorption sites of CO on the Au tubes were considered. The
vibrational frequency of the CO molecule was found to be very different for two
nearly degenerate stable adsorption configurations of Au(5, 3), implying the
possibility of distinguishing these two configurations via measuring the
vibrational frequency of CO in experiments. After CO adsorption, the
conductance of Au(5, 3) decreases by 0.9G0 and the conductance of Au(5, 5)
decreases by approximately 0.5G0. For O-adsorbed Au tubes, O atoms strongly
interact with Au tubes, leading to around 2G0 of drop in conductance for both
Au tubes. These results may have implications for Au-tube-based chemical
sensing. When a monovacancy defect is present, we found that, for both tubes,
the conductance decreases by around 1G0. Another type of defect arising from
the adhesion of one Au atom is also considered. For this case, it is found
that, for the Au(5, 3) tube, the defect decreases the conductance by nearly
1G0, whereas for Au(5, 5), the decrease in conductance is only 0.3G0.Comment: 7 pages, 8 figure
Ethyl 6-[4-(dimethylamino)phenyl]-4-hydroxy-2-oxo-4-(trifluoromethyl)hexahydropyrimidine-5-carboxylate
The title compound, C16H20F3N3O4, was prepared by reaction of 4-(dimethylamino)benzaldehyde, ethyl 4,4,4-trifluoro-3-oxobutanoate and urea. In the title molecule, the pyrimidine ring adopts a half-chair conformation and there is an intramolecular hydrogen bond (O—H⋯O). The crystal structure is stabilized by two types intermolecular hydrogen bonds (N—H⋯O and N—H⋯N)
catena-Poly[[[triaquacopper(II)]-μ2-pyrazine-2,3-dicarboxylato] monohydrate]
The Cu atom in the title complex, {[Cu(C6H2N2O4)(H2O)3]·H2O}n or {[Cu(L)(H2O)3]·H2O}n (L is pyrazine-2,3-dicarboxylate), displays octahedral coordination formed by the ligand L and three coordinated water molecules. The ligand L is tridentate, with one N atom of the pyrazine ring and one O atom of one carboxylate group forming a chelate ring, whereas one O atom from the second carboxylate group is coordinated to another Cu atom. The ligand L links molecules to form an infinite chain parallel to the [101] direction. The chains are further linked through O—H⋯O and O—H⋯N hydrogen bonds involving the water molecules to build up a three-dimensional network
Activation of PI3K/AKT and ERK MAPK signal pathways is required for the induction of lytic cycle replication of Kaposi's Sarcoma-associated herpesvirus by herpes simplex virus type 1
<p>Abstract</p> <p>Background</p> <p>Kaposi's sarcoma-associated herpesvirus (KSHV) is causally linked to several acquired immunodeficiency syndrome-related malignancies, including Kaposi's sarcoma (KS), primary effusion lymphoma (PEL) and a subset of multicentric Castleman's disease. Regulation of viral lytic replication is critical to the initiation and progression of KS. Recently, we reported that herpes simplex virus type 1 (HSV-1) was an important cofactor that activated lytic cycle replication of KSHV. Here, we further investigated the possible signal pathways involved in HSV-1-induced reactivation of KSHV.</p> <p>Results</p> <p>By transfecting a series of dominant negative mutants and protein expressing constructs and using pharmacologic inhibitors, we found that either Janus kinase 1 (JAK1)/signal transducer and activator of transcription 3 (STAT3) or JAK1/STAT6 signaling failed to regulate HSV-1-induced KSHV replication. However, HSV-1 infection of BCBL-1 cells activated phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB, also called AKT) pathway and inactivated phosphatase and tensin homologue deleted on chromosome ten (PTEN) and glycogen synthase kinase-3β (GSK-3β). PTEN/PI3K/AKT/GSK-3β pathway was found to be involved in HSV-1-induced KSHV reactivation. Additionally, extracellular signal-regulated protein kinase (ERK) mitogen-activated protein kinase (MAPK) pathway also partially contributed to HSV-1-induced KSHV replication.</p> <p>Conclusions</p> <p>HSV-1 infection stimulated PI3K/AKT and ERK MAPK signaling pathways that in turn contributed to KSHV reactivation, which provided further insights into the molecular mechanism controlling KSHV lytic replication, particularly in the context of HSV-1 and KSHV co-infection.</p
Epstein-Barr virus encoded latent membrane protein 1 regulates mTOR signaling pathway genes which predict poor prognosis of nasopharyngeal carcinoma
<p>Abstract</p> <p>Background</p> <p>The oncoprotein Epstain-Barr Virus (EBV)-encoded latent membrane protein1 (LMP1) modulates the pathological effects of the NF-κB, AP-1 and JAK/STAT pathways in nasopharyngeal carcinoma (NPC).</p> <p>Methods</p> <p>Microarray analysis was performed on the NPC cell line HONE1 stably transfected with a LMP1-expression plasmid or an empty vector. Based on assigned pathways analyzed using the KEGG database, the mTOR signaling pathway was selected for verification by quantitative RT-PCR. Western blot, RNA interference and immunofluorescence were used to determine the relationship between LMP1 and mTOR signing pathway genes, and their clinical significance to NPC.</p> <p>Results</p> <p>Our studies revealed that overexpression of LMP1 upregulated the mTOR signaling pathway, possibly through phosphorylation of AKT/mTOR/P70S6K/4EBP1 in the NPC cell lines HONE1 and 6-10B. Knockdown of LMP1 reduced expression of p-mTOR and p-4EBP1 in EBV-positive NPC cell line C666-1. In addition, LMP1 expression closely correlated with expression of p-mTOR, p-P70S6K and p-4EBP1 in NPC tumors. Expression of p-P70S6K, p-4EBP1 and LMP1, but not p-mTOR, significantly correlated with overall survival of NPC patients. However, only LMP1 was an independent prognostic factor.</p> <p>Conclusions</p> <p>These results suggest that the mTOR signaling pathway is regulated by LMP1 expression in NPC. LMP1 and the genes in the mTOR pathway such as p-P70S6K and p-4EBP1 may be potential prognostic biomarkers.</p
Control of Anticoagulation Therapy in Patients with Atrial Fibrillation Treated with Warfarin:A Study from the Chinese Atrial Fibrillation Registry
Background: Several factors determine the efficacy of warfarin anticoagulation in patients with non-valvular atrial fibrillation (NVAF). This study aimed to use data from the Chinese Atrial Fibrillation Registry study to assess the control of anticoagulation therapy in Chinese patients with NVAF treated with warfarin. Material/Methods: From the Chinese Atrial Fibrillation Registry study the anticoagulant use and dosing, the time in therapeutic range (TTR) of the international normalized ratio (INR), and standard deviation of the observed INR values (SD INR), and their influencing factors were evaluated. Results: The median INR and SD INR were 2.04 (IQR 1.71–2.41) and 0.50 (IQR, 0.35–0.69), respectively. The median TTR was 51.7% (IQR, 30.6–70.1%) and only 25.1% had a TTR ≥70%. Age was ≥70 years (OR, 0.72; 95% CI, 0.55–0.94; P=0.015), bleeding history (OR 0.48; 95% CI, 0.23–0.89; P=0.029), the use of a single drug (OR, 0.62; 95% CI, 0.42–0.92; P=0.016), more than drug (OR, 0.60; 95% CI, 0.41–0.88; P=0.009), and lack of assessment of bleeding risk (OR, 0.72; 95% CI, 0.54–0.97; P=0.033) were associated with TTR <70% (INR 2.0–3.0). Coronary heart disease (CHD) and peripheral artery disease (PAD) (OR, 0.69; 95% CI, 0.52–0.90; P=0.007) and diabetes mellitus (OR, 0.79; 95% CI, 0.62–0.99; P=0.044) were associated with increased variability in INR (SD INR ≥0.5). Conclusions: In Chinese patients with NVAF, warfarin anticoagulation was associated with lower TTR and less stable anticoagulation than in current guidelines, and risk factors for reduced safety and efficacy were identified. </p
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