ABSTRACT
Light, a nondestructive and remotely controllable external stimulus, effectively triggers a variety of electron-transfer phenomena in metal complexes. One prime example includes using light in molecular cyanide-bridged [FeCo] bimetallic Prussian blue analogues, where it switches the system between the electron-transferred metastable state and the system's ground state. If this process is coupled to a ferroelectric-type phase transition, the generation and disappearance of macroscopic polarization, entirely under light control, become possible. In this research, we successfully executed a nonpolar-to-polar phase transition in a trinuclear cyanide-bridged [Fe2Co] complex crystal via directional electron transfer. Intriguingly, by exposing the crystal to the wavelength of lightâ785 nmâwithout any electric fieldâwe can drive this ferroelectric phase transition to completely depolarize the crystal, during which a measurable electric current response can be detected. These discoveries signify an important step toward the realization of fully light-controlled ferroelectric memory devices.
ABSTRACT
An octacoordinated Fe(II) complex, [FeII(dpphen)2](BF4)2·1.3H2O (1; dpphen = 2,9-bis(pyrazol-1-yl)-1,10-phenanthroline), with a pseudo-D2d-symmetric metal center has been synthesized. Magnetic, high-frequency/-field electron paramagnetic resonance (HF-EPR), and theoretical investigations reveal that 1 is characterized by uniaxial magnetic anisotropy with a negative axial zero-field splitting (ZFS) (D ≈ -6.0 cm-1) and a very small rhombic ZFS (E ≈ 0.04 cm-1). Under applied dc magnetic fields, complex 1 exhibits slow magnetic relaxation at low temperature. Fitting the relaxation time with the Arrhenius mode combining Orbach and tunneling terms affords a good fit to all the data and yields an effective energy barrier (17.0 cm-1) close to the energy gap between the ground state and the first excited state. The origin of the strong uniaxial magnetic anisotropy for 1 has been clearly understood from theoretical calculations. Our study suggests that high-coordinated compounds featuring a D2d-symmetric metal center are promising candidates for mononuclear single-molecule magnets.
ABSTRACT
Water reorientation is essential in a wide range of chemical and biological processes. However, the effects of such reorientation through rotation around the metal-oxygen bond on the chemical and physical properties of the resulting complex are usually ignored. Most studies focus on the donor property of water as a recognized σ donor-type ligand rather than a participant in the π interaction. Although a theoretical approach to study water-rotation effects on the functionality of a complex has recently been conducted, it has not been experimentally demonstrated. In this study, we determine that the magnetic anisotropy of a Co(II) complex can be effectively controlled by the slight rotation of coordinating water ligands, which is achieved by a two-step structural phase transition. When the water molecule is rotated by 21.2 ± 0.2° around the Co-O bond, the directional magnetic susceptibility of the single crystal changes by approximately 30% along the a-axis due to the rotation of the magnetic anisotropy axis through the modification of the π interaction between cobalt(II) and the water ligand. The theoretical calculations further support the hypothesis that the reorientation of water molecules is a key factor contributing to the magnetic anisotropy transition of this complex.
ABSTRACT
The Tie-2 receptor has been shown to play a role in angiogenesis in atherosclerosis. The conventional method assaying the level of soluble Tie-2 (sTie-2) was ELISA. However, this method has some disadvantages. The aims of this research are to establish a more simple detection method, the optical protein-chip based on imaging ellipsomtry (OPC-IE) applying to Tie-2 assay. The sTie-2 biosensor surface on silicon wafer was prepared first, and then serum levels of sTie-2 in 38 patients with AMI were measured on admission (day 1), day 2, day 3 and day 7 after onset of chest pain and 41 healthy controls by ELISA and OPC-IE in parallel. Median level of sTie-2 increased significantly in the AMI patients when compared with the controls. Statistics showed there was a significant correlation in sTie-2 results between the two methods (r=0.923, P<0.01). The result of this study showed that the level of sTie-2 increased in AMI, and OPC-IE assay was a fast, reliable, and convenient technique to measure sTie-2 in serum.
Subject(s)
Myocardial Infarction/blood , Myocardial Infarction/diagnosis , Optical Phenomena , Protein Array Analysis/methods , Receptor, TIE-2/blood , Receptor, TIE-2/chemistry , Animals , Biosensing Techniques , Enzyme-Linked Immunosorbent Assay , Feasibility Studies , Humans , Mice , SolubilityABSTRACT
INTRODUCTION: Subjective cognitive decline (SCD) refers to individuals' perceived decline in memory and/or other cognitive abilities relative to their previous level of performance, while objective neuropsychological deficits are not observed. SCD may represent a preclinical phase of Alzheimer's disease. At this very early stage of decline, intervention could slow the rate of incipient decline to prolong and preserve cognitive and functional abilities. However, there is no effective treatment recommended for individuals with SCD. Acupuncture, as a non-pharmacological intervention, has been widely employed for patients with cognitive disorders. METHODS AND ANALYSIS: The proposed study is a randomised, assessor-blinded and placebo-controlled study that investigates the efficacy and mechanism of acupuncture in SCD. Sixty patients with SCD will be randomly allocated either into an acupuncture group or a sham acupuncture group. They will receive 24 sessions of real acupuncture treatment or identical treatment sessions using a placebo needle. Global cognitive changes based on a multidomain neuropsychological test battery will be evaluated to detect the clinical efficacy of acupuncture treatment at baseline and end of treatment. MRI scans will be used to explore acupuncture-related neuroplasticity changes. Correlation analyses will be performed to investigate the relationships between the changes in brain function and symptom improvement. ETHICS AND DISSEMINATION: The trial was approved by the research ethics committee. The results of the study will be published in a peer-reviewed academic journal and will also be disseminated electronically through conference presentations. TRIAL REGISTRATION NUMBER: NCT03444896.
Subject(s)
Acupuncture Therapy , Cognitive Dysfunction/therapy , Acupuncture Therapy/methods , Aged , Brain/physiopathology , Cognitive Dysfunction/physiopathology , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Randomized Controlled Trials as Topic , Treatment OutcomeABSTRACT
<p><b>Objective</b>To investigate the effects of resveratrol in the cryopreservation medium on the quality and function of post-thaw sperm.</p><p><b>METHODS</b>Semen samples were obtained from 50 normozoospermic and 50 oligoasthenozoospermic men, liquefied and then cryopreserved in the glycerol-egg yolk-citrate (GEYC) medium with or without 30 μmol/L resveratrol. Sperm motility, viability and acrosome reaction (AR) were examined before and after thawing. Sperm lipid peroxidation and the level of reactive oxygen species (ROS) were measured using commercial malondialdehyde (MDA) and the ROS assay kit. Sperm mitochondrial membrane potential (MMP) and DNA damage were determined by Rhodamine 123 staining and TUNEL.</p><p><b>RESULTS</b>The percentage of progressively motile sperm (PMS), total sperm motility, sperm viability, MMP and AR were significantly decreased (P <0.05) while the levels of sperm ROS, MDA and DNA fragmentation index (DFI) remarkably increased in both the normozoospermia and oligoasthenozoospermia groups after cryopreservation as compared with those in the fresh ejaculate (P <0.05). In comparison with the non-resveratrol control, the post-thaw sperm cryopreserved with 30 μmol/L resveratrol showed markedly higher PMS ([32.7 ± 4.8] vs [43.1 ± 6.3] %, P <0.05), total motility ([44.8 ± 6.9] vs [56.9 ± 7.4] %, P <0.05), viability ([52.3 ± 6.1] vs [67.5 ± 5.6] %, P <0.05), MMP ([56.5 ± 7.0] vs [63.4 ± 7.5] %, P <0.05) and AR ([16.6 ± 3.8] vs [26.3 ± 4.7] %, P <0.05) but lower ROS, MDA and DFI (all P <0.05) in the normozoospermia group, and so did the post-thaw sperm in the oligoasthenozoospermia group, with a particularly lower DFI ([28.5 ± 4.8] vs [36.3 ± 5.7]%, P <0.01).</p><p><b>CONCLUSIONS</b>Resveratrol in the cryopreservation medium can improve the quality and function of post-thaw human sperm by reducing cryopreservation-induced sperm injury and the level of ROS.</p>
Subject(s)
Animals , Humans , Male , Acrosome , Antioxidants , Pharmacology , Cryopreservation , Methods , DNA Fragmentation , Lipid Peroxidation , Malondialdehyde , Membrane Potential, Mitochondrial , Reactive Oxygen Species , Resveratrol , Pharmacology , Semen Analysis , Semen Preservation , Sperm Motility , Spermatozoa , PhysiologyABSTRACT
Objective To investigate the correlation between deep vein thrombosis(DVT) and clinical laboratory tests in the regulation of hemostasis. Methods Endothelin-1 (ET-1), thrombomodulin (TM), P-selectin, prothrombin fragment _ 1+2 (F_ 1+2 ), thrombin-antithrombin complex (TAT), thrombus precursor protein (TpP) and D-Dimer (D-D) were measured in DVT patients (n=72) and normal individuals (n=20) with ELISA method. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and accuracy were evaluated for each of the items, and the area of the underlying receiver operating characteristic curve (AUC ROC ) was used to appraise diagnostic efficiency. Results Except ET-1, there were significant differences between the DVT group and normal control group in the other items. The AUC ROC of P-selectin, F_ 1+2 , TpP and D-D was bigger than that of ET-1, TM and TAT (P0.05). The TpP had the highest sensitivity, NPV and accuracy, and the D-D had the highest specificity and PPV. Conclusion The increase of D-D and TpP could reflect the occurrence of continuous coagulation and fibrolysis respectively. Thus the combination of measuring TpP and D-D could provide better laboratory evidence for the diagnosis of patients with DVT.
ABSTRACT
Objective To study the changes of plasma biomolecules in patients with acute cerebral infarction(ACI) and the potential influences from lumbrukinase and aspirin(ASA). Methods Seventy patients with ACI were randomly divided into three groups according to the ways of administration: lumbrukinase group(n=26),ASA group(n=24)and lumbrukinase + ASA group(n=20).Plasma levels of P-selectin,D-dimer(D-D),tissue plasminogen activator(t-PA),plasminogen activator inhibitor-1(PAI-1),plasmin-antiplasmin complex(PAP),thrombin-antithrombin complex(TAT),homocysteine(Hcy) and thrombin-activatable fibrinolysis inhibitor(TAFI) were measured in these patients with ACI and normal individuals(n=20) by ELISA method.Changes of these parameters were detected before and after the treatment,and the diagnostic efficiencies for ACI were compared by receiver characteristic curve(ROC).Results Before the treatment,all the parameters in patients with ACI were significantly higher than those in the healthy controls(P0.05).However,there were significant changes of PAP in the lumbrukinase group(P