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1.
Phys Rev Lett ; 132(7): 076701, 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-38427900

RESUMEN

Magnon transistors that can effectively regulate magnon transport by an electric field are desired for magnonics, which aims to provide a Joule-heating free alternative to the conventional electronics owing to the electric neutrality of magnons (the key carriers of spin-angular momenta in the magnonics). However, also due to their electric neutrality, magnons have no access to directly interact with an electric field and it is thus difficult to manipulate magnon transport by voltages straightforwardly. Here, we demonstrated a gate voltage (V_{g}) applied on a nonmagnetic metal and magnetic insulator (MI) interface that bent the energy band of the MI and then modulated the probability for conduction electrons in the nonmagnetic metal to tunnel into the MI, which can consequently enhance or weaken the spin-magnon conversion efficiency at the interface. A voltage-controlled magnon transistor based on the magnon-mediated electric current drag (MECD) effect in a Pt-Y_{3}Fe_{5}O_{12}-Pt sandwich was then experimentally realized with V_{g} modulating the magnitude of the MECD signal. The obtained efficiency (the change ratio between the MECD voltage at ±V_{g}) reached 10%/(MV/cm) at 300 K. This prototype of magnon transistor offers an effective scheme to control magnon transport by a gate voltage.

2.
Phys Rev Lett ; 130(21): 216701, 2023 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-37295074

RESUMEN

The relativistic spin Hall effect and inverse spin Hall effect enable the efficient generation and detection of spin current. Recently, a nonrelativistic altermagnetic spin splitting effect (ASSE) has been theoretically and experimentally reported to generate time-reversal-odd spin current with controllable spin polarization in antiferromagnet RuO_{2}. The inverse effect, electrical detection of spin current via ASSE, still remains elusive. Here we show the spin-to-charge conversion stemming from ASSE in RuO_{2} by the spin Seebeck effect measurements. Unconventionally, the spin Seebeck voltage can be detected even when the injected spin current is polarized along the directions of either the voltage channel or the thermal gradient, indicating the successful conversion of x- and z-spin polarizations into the charge current. The crystal axes-dependent conversion efficiency further demonstrates that the nontrivial spin-to-charge conversion in RuO_{2} is ascribed to ASSE, which is distinct from the magnetic or antiferromagnetic inverse spin Hall effects. Our finding not only advances the emerging research landscape of altermagnetism, but also provides a promising pathway for the spin detection.

3.
Zhonghua Yi Xue Za Zhi ; 102(36): 2861-2867, 2022 Sep 27.
Artículo en Zh | MEDLINE | ID: mdl-36153871

RESUMEN

Objective: To evaluate the effect of autologous hematopoietic stem cell transplantation (ASCT) on minimal residual disease (MRD) in patients with multiple myeloma (MM). Method: From August 2018 to August 2021, 92 patients newly diagnosed with MM who had received either the bortezomib combined with cyclophosphamide and dexamethasone (VCD) or the bortezomib, lenalidomide and dexamethasone (VRD) induction regimens followed by sequential ASCT were assessed for overall survival (OS) and the MRD negative rate. The differences in efficacy at 100 days after transplantation were assessed according to factors, including age, risk stratification, target organ damage, and pre-transplant regimen, etc. Results: Among the 92 patients, there were 45 males and 47 females, with a median age of 57.3 (35-67) years. Fifty-seven patients received the VCD regimen, and 35 received VRD as induction regimen. Forty-three patients received busulphan combined with cyclophosphamide and etoposide (BCV), and 49 patients received high-dose melphan (HDM) regimen as pre-transplantation treatment. After transplantation, the total complete remission (CR) rate of 92 patients increased from 23.9% (22/92) to 58.7% (54/92), and the MRD negative rate increased from 4.4% (4/92) to 33.7% (31/92), and the differences were statistically significant (all P<0.05). After transplantation, the MRD negative rates of patients with PR, VGPR and ≥CR before transplantation were 17.6% (6/34), 33.3% (12/36) and 59.1% (13/22), respectively (P=0.006). The CR rates of patients with or without plasmacytoma at initial diagnosis were 36.4% (4/11) and 65.4% (53/81), respectively (P=0.029), and the MRD negative rates were 18.2% (2/11) and 39.5% (32/81), respectively (P=0.037), and the differences were statistically significant. The MRD negative rates in high-risk patients and standard-risk group were 30.5% (12/28) and 42.9% (18/59), respectively (P=0.258). For patients who achieved efficacy above VGPR before transplantation, the MRD negative rates after transplantation in VCD-induced group and VRD group were 29% (9/31) and 59.3% (16/27), respectively (P=0.033), and in BCV group and HDM group were 24% (6/25) and 57.6% (19/33), respectively (P=0.016), the differences between the groups were both statistically significant. Conclusion: ASCT can overcome the adverse factors such as high-risk cytogenetic abnormalities, and significantly improve the CR rate and MRD negative rate of MM patients. However, the benefit for patients with plasmacytoma at initial diagnosis is not as good as that of patients without.


Asunto(s)
Trasplante de Células Madre Hematopoyéticas , Mieloma Múltiple , Plasmacitoma , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Bortezomib , Busulfano/uso terapéutico , Ciclofosfamida/uso terapéutico , Dexametasona/uso terapéutico , Etopósido/uso terapéutico , Femenino , Humanos , Lenalidomida/uso terapéutico , Masculino , Persona de Mediana Edad , Mieloma Múltiple/diagnóstico , Mieloma Múltiple/tratamiento farmacológico , Neoplasia Residual , Plasmacitoma/tratamiento farmacológico , Trasplante de Células Madre , Trasplante Autólogo , Resultado del Tratamiento
4.
J Appl Microbiol ; 130(1): 100-108, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32648664

RESUMEN

AIMS: Phospholipase A2 (PLA2 ) is a diverse superfamily that hydrolyzes fatty acyl ester bonds at the sn-2 position of phospholipids. The correlation between phospholipid metabolism and the anabolism of neutral lipids remains unclear in yeasts. This study aims to explore the effects of PLA2 on lipid accumulation in the oleaginous yeast Yarrowia lipolytica. METHODS AND RESULTS: This study identified an actively expressed phospholipase A2 gene (PLA2-3, YAIL0_E16060g) in Y. lipolytica by quantitative PCR analysis. The gene PLA2-3 was disrupted in the strain po1gΔKu70 by homologous recombination and in the strain po1g-G3 by a CRISPR-Cas9 system, which caused an increase in stress sensitivity while the cell growth was not altered under fermentative conditions. Lipid production was performed in both flasks and bioreactors. The results showed that the lipid titre and lipid content were improved over 25% and 8-30%, respectively, in PLA2-3 disrupted strains compared to the controls. CONCLUSIONS: Disruption of the phospholipase PLA2-3 gene could effectively improve lipid production in Y. lipolytica. SIGNIFICANCE AND IMPACT OF THE STUDY: This study presented a strategy on improving the lipid production of oleaginous yeasts and a similar strategy might be used in other oleaginous microbes.


Asunto(s)
Proteínas Fúngicas/genética , Metabolismo de los Lípidos , Fosfolipasas A2/genética , Yarrowia/metabolismo , Biocombustibles/microbiología , Reactores Biológicos , Fermentación , Metabolismo de los Lípidos/genética , Lípidos/biosíntesis , Ingeniería Metabólica , Mutación , Fosfolipasas A2/deficiencia , Yarrowia/enzimología , Yarrowia/genética
5.
Zhonghua Wai Ke Za Zhi ; 58(8): 626-630, 2020 Aug 01.
Artículo en Zh | MEDLINE | ID: mdl-32727195

RESUMEN

Objective: To examine the value serum calcium and intact parathyroid hormone (iPTH) levels measured on the first day after total thyroidectomy on prediction for permanent hypoparathyroidism. Methods: Totally 546 patients with thyroid cancer and benign thyroid lesions who underwent total thyroidectomy at Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University from February 2008 to December 2018 were analyzed retrospectively. There were 158 males and 388 females aging (50.9±13.2) years (range: 19.0 to 79.2 years). Serum calcium and iPTH levels were collected before surgery, on the first day and 6 months after surgery. Logistic regression was used to analyze the correlation between each data and the occurrence of permanent hypoparathyroidism after surgery.The area under the receiver operating characteristic curve was used to evaluate the predictive power of iPTH for postoperative occurrence of permanent hypoparathyroidism. Results: Among the 546 cases of total thyroidectomy, 22 cases of permanent hypoparathyroidism occurred, with an incidence of 4.0% (22/546). Multivariate analysis showed that iPTH levels on the first day after total thyroidectomy (OR=2.932, 95%CI: 1.129 to 7.616, P=0.027) and serum calcium levels (OR=2.584, 95%CI: 1.017 to 6.567, P=0.046) were independent prognosis factors for postoperative permanent hypoparathyroidism. When the threshold value of iPTH at 24 hours after total thyroidectomy was 5.51 ng/L, the AUC was 0.956 (95%CI: 0.936 to 0.972, P=0.000), sensitivity was 100%, specificity was 85.1%, positive predictive value was 22%, negative predictive value was 100%. When the threshold value of serum calcium at 24 hours after total thyroidectomy was 1.93 mmol/L, the AUC was 0.733 (95%CI: 0.694 to 0.770, P=0.000), sensitivity was 63.6%, specificity was 78.1%, positive predictive value of 10.8% and negative predictive value of 98.1%. Conclusions: Serum iPTH and calcium levels on the first day after total thyroidectomy were related to the occurrence of permanent hypoparathyroidism postoperatively. The predictive value of iPTH level is higher than that of serum calcium level.


Asunto(s)
Calcio/sangre , Hipoparatiroidismo/sangre , Hormona Paratiroidea/sangre , Enfermedades de la Tiroides/cirugía , Tiroidectomía/efectos adversos , Adulto , Anciano , Femenino , Humanos , Hipoparatiroidismo/etiología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico , Estudios Retrospectivos , Enfermedades de la Tiroides/sangre , Tiroidectomía/métodos , Adulto Joven
6.
Phys Rev Lett ; 120(9): 097205, 2018 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-29547317

RESUMEN

The key physics of the spin valve involves spin-polarized conduction electrons propagating between two magnetic layers such that the device conductance is controlled by the relative magnetization orientation of two magnetic layers. Here, we report the effect of a magnon valve which is made of two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer (Au). When a thermal gradient is applied perpendicular to the layers, the inverse spin Hall voltage output detected by a Pt bar placed on top of the magnon valve depends on the relative orientation of the magnetization of two YIG layers, indicating the magnon current induced by the spin Seebeck effect at one layer affects the magnon current in the other layer separated by Au. We interpret the magnon valve effect by the angular momentum conversion and propagation between magnons in two YIG layers and conduction electrons in the Au layer. The temperature dependence of the magnon valve ratio shows approximately a power law, supporting the above magnon-electron spin conversion mechanism. This work opens a new class of valve structures beyond the conventional spin valves.

7.
Nanotechnology ; 29(24): 245601, 2018 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-29583131

RESUMEN

Multiphase CoCr2O4/Ni core-shell nanowires (NWs) have been synthesized within anodic aluminum oxide membranes by the combination of the sol-gel method with electrodeposition techniques. X-ray diffraction and x-ray photoemission spectroscopy results confirmed the formation of a cubic spinel structure of CoCr2O4 shell with space group Fd-3m (227). The morphology and composition of the as-grown NWs were studied by field emission scanning electron microscopy, as well as transmission electron microscopy. The magnetic properties of the CoCr2O4 NT shell and hybrid CoCr2O4/Ni NWs were measured at low temperature using a physical property measurement system. The temperature dependence of the magnetization curves showed that CoCr2O4 NTs undergo a transition from a paramagnetic state to a ferrimagnetic state at about 90 K and a spiral ordering transition temperature near 22 K. An enhanced coercivity and saturation field were observed for the CoCr2O4/Ni core-shell NWs compared to the single-phase Ni NWs. Micromagnetic simulation results indicated that there is a strong coupling between the shell and core layers during the magnetization reversal process. The combination of hard CoCr2O4 and soft Ni in a single NW structure may have potential applications in future multifunctional devices.

8.
Beijing Da Xue Xue Bao Yi Xue Ban ; 49(6): 996-1002, 2017 Dec 18.
Artículo en Zh | MEDLINE | ID: mdl-29263471

RESUMEN

OBJECTIVE: To evaluate the efficiency of thoracic endovascular aortic repair (TEVAR) in dealing with abdominal aortic branch malperfusion based on the analysis of aortic computed tomography angiography (CTA) images in pre- and post-TEVAR. METHODS: Retrospective analysis from September 2015 to March 2016 in single institution to 32 patients, diagnosed as Stanford B aortic dissection with abdominal aortic branch malperfusion, CTA images in pre- and post-TEVAR were collected. Based on the aortic branch malperfusion pattern redefined by Nagamine, we identified and characterized branch malperfusion pattern for four abdominal aortic branches (celiac trunk, superior mesenteric artery, bilateral renal artery) in statistical analysis. RESULTS: In the four abdominal aortic branches (total 128 branches), 86 branches (67.2%) expressed with Class I patterns, in which subtype I-b presented with 0.8%, subtype I-c with 5.5%; 14 branches (10.9%) expressed with Class II patterns, in which subtype II-b-1 with 3.9%, subtype II-b-2 with 3.1%; 16 branches (12.5%) expressed with Class III patterns, all with subtype III-a, no subtype III-b and III-c presented. The remaining 12 branches were normal. The 100% successful rate of TEVAR obtained in 32 patients performed. The mean following-up was 4 months. Aortic CTA showed that among the 14 "high-risk" abdominal aortic branch malperfusion, 13 (92.9%) with obvious branch malperfusion in post-TEVAR were observed to improve, and the remaining one branch malperfusion (7.1%) was observed to change from subtype I-b to I-c. CONCLUSION: Few ratios in abdominal aortic branches suffered with obvious malperfusion complicated by Stanford B aortic dissection. For branches with "high-risk" malperfusion pattern, optimal changes were observed in abdominal aortic branch without revascularization in post-TEVAR, as well other branches with non-"high-risk" pattern perfusion were mostly stable in post-TEVAR. It could be of profound benefit to extend branch malperfusion patterns redefined by Nagamine in clinical practice to assess aortic dissection and in further guide for revascularization or not.


Asunto(s)
Aneurisma de la Aorta Torácica/cirugía , Implantación de Prótesis Vascular , Procedimientos Endovasculares , Abdomen , Disección Aórtica , Aorta , Aortografía , Angiografía por Tomografía Computarizada , Humanos , Estudios Retrospectivos , Resultado del Tratamiento
9.
Zhonghua Wai Ke Za Zhi ; 55(9): 696-701, 2017 Sep 01.
Artículo en Zh | MEDLINE | ID: mdl-28870056

RESUMEN

Objective: To observe the outcome of breast reconstruction with autologous fat grafting in the patients following treatment for breast cancer. Methods: The clinical data of 22 patients after breast cancer modified radical mastectomy with fat grafting for breast reconstruction from January 2012 to March 2015 at Department of Body Contouring and Liposuction Center of Plastic Surgery, Hospital of Peking Union Medical College were analyzed retrospectively. The age of 22 patients (all female) was 28 to 54 years. Fifteen patients were performed breast modified radical mastectomy 5 to 16 year ago without radiotherapy, 7 patients were performed breast modified radical mastectomy following regular radiotherapy 2 years ago. Low negative pressure liposuction technical was applied to harvest fat tissue for 400 to 800 ml which was filtrated and purified by cotton pad method in low temperature environment. Fat grafting was performed with multi-level and multi-tunnel and in multi-point injection ways. All patients were followed up by regular imaging evaluation with MRI or ultrasonography after operation every 3 months. Results: All breast reconstruction were successfully performed in 22 patients, no severe complications occurred. Among 15 patients without radiotherapy, 12 patients were performed with autologous fat grafting for breast reconstruction, 3 patients with prosthetic implantation for breast augmentation after autologous fat grafting. Among 7 patients with radiotherapy, 6 patients were performed with autologous fat grafting for breast reconstruction, 1 patient with prosthetic implantation for breast augmentation after autologous fat grafting. The volume of fat grafting was 104 to 380 ml. It took 2.5 hours to finish the operation including 1.0 to 1.5 hours for liposuction and 40 minutes for fat grafting. Next fat grafting were performed after 3 months. The fat of the breast were survived well detecting by MRI, only 1 patient had a cystic nodule which had been resected during nipple reconstruction. Ultrasonography screened several cystic nodules with the major axis of 0.1 to 0.2 cm in the breast, which couldn't be found by palpating in 18 patients. The patients were followed up for 18 to 36 months, the outcome were satisfactory. Conclusion: Autologous fat grafting for breast reconstruction simplifies the operation program with satisfied results and avoids the complications of breast reconstruction with skin flap.


Asunto(s)
Tejido Adiposo/trasplante , Neoplasias de la Mama/cirugía , Mama/cirugía , Mamoplastia/métodos , Adulto , Neoplasias de la Mama/radioterapia , Femenino , Humanos , Lipectomía , Mastectomía , Persona de Mediana Edad , Estudios Retrospectivos , Recolección de Tejidos y Órganos/métodos , Trasplante Autólogo , Resultado del Tratamiento
10.
Nanotechnology ; 27(4): 045708, 2016 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-26656305

RESUMEN

One-dimensional core-shell nanostructures consisting of a ferromagnetic cobalt core and a multiferroic BiFeO3 (BFO) shell were fabricated by an artificial two-step methodology. The coupling between the ferromagnetic core and multiferroic shell manifests a significant exchange bias effect which gives a clear demonstration of the anti-ferromagnetic functionality of the BFO shell material. Exchange biases of 30 Oe and 60 Oe are observed at 300 K and at 5 K, respectively. Superparamagnetic contributions at lower temperatures play an important role in contributing to overall magnetic behavior. Dominant shape anisotropy causes parallel alignment of the easy magnetization axis along the axis of core-shell nanowires. A coherent mode of the magnetization reversal mechanism is observed by the angular dependence of coercivity (H c). This versatile two-step methodology can be employed to fabricate and investigate many other hybrid nanostructures leading to a vast scope of investigation for researchers.

12.
Genet Mol Res ; 15(2)2016 04 25.
Artículo en Inglés | MEDLINE | ID: mdl-27173231

RESUMEN

Bone fractures or bones subjected to open conduction and internal fixation are easily infected by bacteria; bacterial lipopolysaccharide (LPS) has been recognized as an important pathogenic factor affecting bone fracture healing. Therefore, the effect of LPS on bone metabolism is relevant for bone healing. In this study, we investigated the effect of LPS on the expression of Toll-like receptor (TLR)-4 (an LPS receptor) by using real-time quantitative PCR and western blotting. We also examined the regulatory role of LPS in osteoblast differentiation by measuring the ALP activity, matrix mineralization, and ALP, OCN, and Runx2 mRNA (essential factors affecting osteoblast differentiation) expression in LPS-treated mouse osteoblast MC3T3-E1 cells. We also evaluated the effect of TLR-4 on LPS-mediated inhibition of osteoblast differentiation using RNA interference. LPS promotes TLR-4 mRNA and protein expression in MC3T3-E1 cells (P < 0.05, P < 0.01 or P < 0.001), and inhibits osteoblast differentiation by downregulating matrix mineralization and ALP activity (P < 0.05, P < 0.01 or P < 0.001), and suppressing the expression ALP, OCN, and Runx2 mRNA in MC3T3-E1 cells (P < 0.05 or P < 0.01). Conversely, RNAi-mediated TLR-4 knockdown abrogates the LPS-mediated inhibition of osteoblast differentiation (P < 0.05 or P < 0.01). In summary, LPS was shown to inhibit osteoblast differentiation by suppressing the expression of ALP, OCN, and Runx2 in a TLR-4-dependent manner. The results of this study may provide insights into the signal pathway of LPS-induced bone loss or delayed bone fracture healing.


Asunto(s)
Diferenciación Celular/efectos de los fármacos , Fracturas Óseas/genética , Osteoblastos/metabolismo , Receptor Toll-Like 4/biosíntesis , Proteínas Adaptadoras Transductoras de Señales/biosíntesis , Animales , Línea Celular , Subunidad alfa 1 del Factor de Unión al Sitio Principal/biosíntesis , Fracturas Óseas/tratamiento farmacológico , Fracturas Óseas/patología , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Lipopolisacáridos/administración & dosificación , Proteínas de la Membrana/biosíntesis , Ratones , Osteoblastos/patología , Osteogénesis/efectos de los fármacos , ARN Mensajero/genética , Transducción de Señal/efectos de los fármacos , Receptor Toll-Like 4/genética
14.
Phys Rev Lett ; 115(15): 157204, 2015 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-26550750

RESUMEN

Double-barrier heterostructures are model systems for the study of electron tunneling and discrete energy levels in a quantum well (QW). Until now resonant tunneling phenomena in metallic QWs have been observed for limited thicknesses (1-2 nm) under which electron phase coherence is conserved. In the present study we show evidence of QW resonance states in Fe QWs up to 12 nm thick and at room temperature in fully epitaxial double MgAlO_{x} barrier magnetic tunnel junctions. The electron phase coherence displayed in this QW is of unprecedented quality because of a homogenous interface phase shift due to the small lattice mismatch at the Fe-MgAlO_{x} interface. The physical understanding of the critical role of interface strain on QW phase coherence will greatly promote the development of spin-dependent quantum resonant tunneling applications.

15.
J Anim Physiol Anim Nutr (Berl) ; 97(3): 475-84, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22416977

RESUMEN

Tea catechins (TC) are polyphenols that have potent antioxidant activity. The objectives of this study were to determine the effects of TC on antioxidant status of hepatocytes challenged with H2 O2 . Primary hepatocytes of goat were exposed to 1 mm H2 O2 without or with 5, 50 and 500 µg/ml TC. The cells were harvested at 48 h post-treatment to determine effects of TC on proliferation, apoptotic features and membrane integrity of cells, and expression of genes and activities of antioxidant enzymes. H2 O2 exposure caused damage to cells (p < 0.001). A lower concentration of TC (5 µg/ml) displayed a protective effect by inhibiting exorbitant cell proliferation and DNA degradation. Both H2 O2 exposure and TC pre-incubation affected expression of antioxidant enzymes at mRNA and protein levels (p < 0.001). The activities of catalase (CAT) (p = 0.027), CuZn-superoxide dismutase (CuZn-SOD) (p < 0.001) and glutathione peroxidase (GPx) (p < 0.001) increased with TC pre-incubation followed by H2 O2 challenge. Changes of CuZn-SOD activity induced by H2 O2 and TC basically paralleled the changes in the corresponding mRNA and protein levels, but the correlation in CAT and GPx expression displayed slightly different patterns at different concentrations of TC. These findings infer that oxidative stress can induce deleterious cellular responses and this unfavourable condition may be alleviated by treatment with TC.


Asunto(s)
Antioxidantes/metabolismo , Camellia sinensis/química , Catecoles/farmacología , Cabras , Hepatocitos/efectos de los fármacos , Peróxido de Hidrógeno/farmacología , Animales , Catecoles/química , Proliferación Celular , Células Cultivadas , Relación Dosis-Respuesta a Droga , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Hepatocitos/citología , Hepatocitos/fisiología , ARN Mensajero/genética , ARN Mensajero/metabolismo
16.
Phys Rev Lett ; 108(13): 137203, 2012 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-22540724

RESUMEN

We report a large and nonvolatile bipolar-electric-field-controlled magnetization at room temperature in a Co(40)Fe(40)B(20)/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O(3) structure, which exhibits an electric-field-controlled looplike magnetization. Investigations on the ferroelectric domains and crystal structures with in situ electric fields reveal that the effect is related to the combined action of 109° ferroelastic domain switching and the absence of magnetocrystalline anisotropy in Co(40)Fe(40)B(20). This work provides a route to realize large and nonvolatile magnetoelectric coupling at room temperature and is significant for applications.

17.
J Nanosci Nanotechnol ; 12(2): 1044-8, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22629892

RESUMEN

We report a detailed investigation of the magnetization reversal by minor loops in Co75Fe25 (t) single layer and Ir22Mn78(10 nm)/CoFe(t) exchange-biased bilayers with different CoFe thicknesses. With increasing CoFe layer thickness in IrMn/CoFe bilayers, the magnetization reversal process shows a transition from the coherent rotation to the domain-wall motion, which is attributed to the competition among the antiferromagnetic domain wall energy, ferromagnetic domain wall energy, and the interface coupling between antiferromagnetic and ferromagnetic layers.

18.
J Nanosci Nanotechnol ; 12(2): 1006-23, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22629887

RESUMEN

Following predictions by first-principles theory of a huge tunnel magnetoresistance (TMR) effect in epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs), measured magnetoresistance (MR) ratios of about 200% at room temperature (RT) have been reported in MgO-based epitaxial MTJs. Recently, a MR ratio of about 600% has been reported at RT in MgO-based MTJs prepared by magnetron sputtering, using amorphous CoFeB as the ferromagnetic electrode. These MTJs show great potential for application in spintronic devices. Fully epitaxial MTJs are excellent model systems that enhance our understanding of the spin-dependent tunneling process as the interface is well defined and can be fully characterized. Both theoretical calculations and experimental results clearly indicate that the interfacial structure plays a crucial role in the coherent tunneling across a single crystal MgO barrier, especially in epitaxial MgO-based MTJs grown by molecular beam epitaxy (MBE). Surface X-ray diffraction, Auger electron spectroscopy, X-ray absorption spectra, and X-ray magnetic circular dichroism techniques have been reported previously for interface characterization. However, no consistent viewpoint has been reached on the interfacial structures (such as FeO layer formation at the bottom Fe/MgO interface), and it is still an open issue. In this article, our recent studies on the interface characterization of MgO-based epitaxial MTJs by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and spin-dependent tunneling spectroscopy, will be presented.

19.
Poult Sci ; 90(4): 766-74, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21406361

RESUMEN

New type gosling viral enteritis virus (NGVEV) caused a serious disease in naive juvenile goslings. In the described studies the performance of 2 vaccines was analyzed: a vaccine containing adjuvanted inactivated NGVEV and a vaccine containing adjuvanted inactivated NGVEV and recombinant goose IL-2. Breeder geese were subcutaneously vaccinated at the beginning of the egg production period with the vaccines. Breeder geese sham vaccinated with PBS served as control. The cellular and humoral immune responses of the vaccinated breeder geese, as well as the presence of maternally derived antibody to NGVEV, were investigated by ELISA, virus neutralization test, and lymphocyte proliferation assay, respectively. A significantly higher immunogenicity (P < 0.05) was induced by the inactivated NGVEV-recombinant goose IL-2 adjuvant vaccine compared with the inactivated NGVEV vaccine. The offspring of the vaccinated birds were challenged with virulent NGVEV (100 50% lethal dose) and the protective efficacy of the vaccines was determined. Furthermore, in a field trial the efficacy of the inactivated NGVEV vaccine was recorded from years 2003 to 2007. No clinical signs or abnormal health status were observed in the vaccinated breeder geese and the progeny. After a single application, >80% protection was shown in the progeny of geese vaccinated against NGVEV challenge for approximately 5 mo. The extensive field trials further demonstrated that vaccination of breeder geese with the inactivated NGVEV vaccine could be a safe and efficacious means to control NGVE disease. Moreover, the level of maternally derived NGVEV antibody titer in the egg yolk reflected the level of NGVEV antibodies in the breeder geese, suggesting that the egg yolk could be used to monitor the vaccination efficacy in commercial goose breeder flocks.


Asunto(s)
Enteritis/prevención & control , Enteritis/veterinaria , Gansos , Inmunización/veterinaria , Enfermedades de las Aves de Corral/virología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/sangre , Yema de Huevo/inmunología , Yema de Huevo/virología , Enteritis/inmunología , Enteritis/virología , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Inmunización/métodos , Interleucina-2/farmacología , Pruebas de Neutralización/veterinaria , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/prevención & control , Distribución Aleatoria , Vacunas de Productos Inactivados/administración & dosificación , Vacunas de Productos Inactivados/inmunología , Vacunas Virales/administración & dosificación
20.
J Food Sci Technol ; 48(4): 447-53, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23572769

RESUMEN

The effects of Ku Ding tea (Lactuca taiwaniana Maxim) and milk powder on biochemical and immunological parameters of Sprague-Dawley rats were investigated and the possibility of use of Ku Ding tea to reduce physiological discomfort of drinking milk powder was assessed. Eighty rats were randomly assigned to four treatments: basal diet (control), basal diet plus whole milk powder (WM), basal diet plus Ku Ding tea (KD) and basal diet plus whole milk powder and Ku Ding tea (MK). Data was collected on animals' final body weight, hematological values, blood biochemical parameters, antioxidation parameters and immune organ weight index. Results showed that final body weight of male KD was significantly lower than that of WM. White blood cell count, monocyte count and granulocyte count of KD rats were significantly lower than those of WM. Compared to the control, single milk powder supplementation numerically increased plasma malondialdehyde. The malondialdehyde in the male KD and MK rats were lower than those in WM and control, although the differences were not significant. No significant differences were found in Na(+)K(+)-adenosine triphosphatase activity, spleen and thymus index in each group. Consumption of Ku Ding tea appeared to lower lipid peroxidation that was induced by milk powder in the rats.

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