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An epidemiological investigation was carried out on a local cluster of outbreak caused by imported cases of Coronavirus Disease 2019 (COVID-19) in rural areas of Chengdu in December 2020, to find out the source of infection and the chain of transmission. According to Prevention and Control Protocol for COVID-19 (Version 7), field epidemiological investigation was adopted, combined with big data technology, video image investigation, gene sequencing and other methods to carry out investigation into COVID-19 cases and infections source tracing, analyze the epidemiological association, and map the chain of transmission. From December 7 to 17, 2020, 13 local COVID-19 confirmed cases and 1 asymptomatic case were diagnosed in Chengdu, of which 12 cases (85.71%) had a history of residence and activity in the village courtyard of Taiping (TP), Pidu (P) District, Chengdu. From November 8, 2020 to November 28, 2020, a group of inbound people form Nepal were transferred to the designated entry personnel quarantine hotel of P District which was adjacent to the TP village. During quarantine, there were 5 cases who tested positive for COVID-19. Through gene sequencing alignment, genes of local cases and Nepalese imported cases from the same period are homologous, all belong to the lineage of L2.2.3 (B.1.36 according to Pangolin lineage typing method). According to the results of field epidemiological investigation and gene sequencing analysis, the index case was most likely infected by contact with household waste of quarantine site. Under the situation of normalization prevention and control of COVID-19, sentinel monitoring of fever clinics in primary medical institutions is the key to early detection of the epidemic. The multi-department joint epidemiological investigation and the application of gene technology are the core links of the investigation and traceability of modern infectious diseases. The allocation of public health resources in rural areas needs to be strengthened. We need to improve the capacity for early surveillance and early warning of the epidemic in rural areas.
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COVID-19 , Epidemias , Surtos de Doenças , Humanos , Quarentena , SARS-CoV-2RESUMO
We have investigated spin pumping from Y3Fe5O12 thin films into Cu, Ag, Ta, W, Pt, and Au with varying spin-orbit coupling strengths. From measurements of Gilbert damping enhancement and inverse spin Hall signals spanning 3 orders of magnitude, we determine the spin Hall angles and interfacial spin mixing conductances for the six metals. The spin Hall angles largely vary as Z(4) (Z: atomic number), corroborating the role of spin-orbit coupling. Amongst the four 5d metals, the variation of the spin Hall angle is dominated by the sensitivity of the d-orbital moment to the d-electron count, confirming theoretical predictions.
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It is widely believed that the mechanism for spin pumping in ferromagnet-nonmagnet bilayers is the exchange interaction between the ferromagnet and nonmagnetic material. We observe 1000-fold exponential decay of spin pumping from thin Y3Fe5O12 films to Pt across insulating barriers, from which exponential decay lengths of 0.16, 0.19, and 0.23 nm are extracted for oxide barriers having band gaps of 4.91, 3.40, and 2.36 eV, respectively. This archetypal signature of quantum tunneling through a barrier underscores the importance of exchange coupling for spin pumping and reveals its dependence on the characteristics of the barrier material.
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OBJECTIVE: To investigate the morphological variation of Oncomelania hupensis shells in Yunnan Province, so as to provide insights into the understanding of O. hupensis genetic evolution and control. METHODS: According to the O. hupensis density, geographical location, altitude, water system and environmental type, 12 administrative villages were sampled from 10 schistosomiasis-endemic counties (districts) in 3 prefectures (cities) of Yunnan Province as snail collection sites. From December 2021 to January 2022, about 200 snails were collected from each collection site, among which thirty adult snails (6 to 7 spirals) were randomly selected from each site, and the 11 morphological indexes of snail shells were measured and subjected to cluster analysis and principal component analysis. RESULTS: Of O. hupensis snails from 12 localities of Yunnan Province, the longest shell (7.33 mm) was detected in snails from Yongle Village, Eryuan County, with the shortest (4.68 mm) in Dongyuan Village, Gucheng District, and the largest angle of apex (59.47°) was measured in snails from Caizhuang Village, Midu County, with the smallest (41.40°) in Qiandian Village, Eryuan County. The mean coefficient of variation was 9.075% among O. hupensis snails from 12 localities of Yunnan Province, with the largest coefficient of variation seen in the thickness of the labra brim (29.809%). Among O. hupensis snails from 12 localities of Yunnan Province, the mean Euclidean distance was 2.26, with the shortest Euclidean distance seen between O. hupensis snails from Qiandian Village of Eryuan County and Wuxing Village of Dali City (0.26), and the largest found between O. hupensis snails from Caizhuang Village of Midu County and Cangling Village of Chuxiong County (8.17). Cluster analysis and principal component analysis classified O. hupensis snails from 12 localities of Yunnan Province into three categories, including the O. hupensis snail samples from Caizhuang Village of Midu County, O. hupensis snail samples from Cangling Village of Chuxiong County, and O. hupensis snail samples from Qiandian Village of Eryuan County, Wuxing Village of Dali City, Yangwu Village of Yongsheng County, Xiaoqiao Village of Xiangyun County, Yongle Village of Eryuan County, Xiaocen Village of Dali City, Anding Village of Nanjian County, Dongyuan Village of Gucheng District, Lianyi Village of Heqing County, and Dianzhong Village of Weishan County. The variations in these three categories of snail samples were mainly measured in the principal component 2 related to the angle of apex and the thickness of the labra brim. CONCLUSIONS: The variations in the Euclidean distance and morphological features of shells of O. hupensis from 12 localities of Yunnan Province gradually rise with the decrease in the latitude of the collection sites. The angle of apex is an indicator for the growth of O. hupensis whorl.
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Gastrópodes , Animais , China , Cidades , Análise por Conglomerados , ÁguaRESUMO
In this study, we used the autocloning effect on pyramid structures to develop broad-bandwidth, omnidirectional antireflection structures for silicon solar cells. The angular dependence of reflectance on several pyramid structures was systematically investigated. The deposition of three-layer autocloned films reduced the refractive index gap between air and silicon, resulting in an increase in the amount of transmitted light and a decrease in the total light escaping. The average reflectance decreased dramatically to ca. 2-3% at incident angles from 0 to 60° for both sub-wavelength- and micrometer-scale pyramid structures. The measured reflectance of the autocloned structure was less than 4% in the wavelength range from 400 to 1000 nm for incident angles from 0 to 60°. Therefore, the autocloning technique, combined with optical thin films and optical gradient structures, is a practical and compatible method for the fabrication of broad-bandwidth, omnidirectional antireflection structures on silicon solar cells.
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Babesiosis is an important tick-transmitted zoonosis caused by hematotropic parasites of the genus Babesia, zoonosis disease, which is widely distributed across the world. There are 12 species of Babesia causing human diseases, including B. microti, B. divergens, B. venatorum and B. duncani. The clinical symptoms of human Babesia infections mainly include fever, headache, chills, myalgia and fatigue, and severe infections may cause death. The diagnosis of babesiosis mainly depends on laboratory testing combined with clinical manifestations and epidemiological surveys, and the diagnostic techniques mainly include microscopic examinations of the blood smears, serological tests and molecular biological assays. Currently, azithromycin-atova-quone or clindamycin-quinine combinations are common treatments for babesiosis. This review summarizes the clinical features following human infections with various species of Babesia, the diagnostic techniques and diagnostic criteria of babesiosis and the currently available treatments for babesiosis.
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Babesia , Babesiose , Carrapatos , Animais , Babesiose/diagnóstico , Babesiose/tratamento farmacológico , Humanos , Microscopia , Zoonoses/diagnósticoRESUMO
OBJECTIVE: To assess the schistosomiasis transmission risk in Nanjing County, so as to provide the scientific evidence for the development of the schistosomiasis control strategy and consolidation of the control achievements. METHODS: On May 2019, the Deqiu Village in Deqiu Town and Baiyun Village in Nanjing Town of Yunnan Province, where schistosomiasis were historically relatively highly endemic, were selected to assess the risk of transmission of schistosomiasis by means of a retrospective review of the data pertaining to the historical endemic situation and schistosomiasis control, combined with a cross-sectional survey of snail and wild feces distribution. RESULTS: During the period between 2017 and 2018, the mean sero-prevalence rates of Schistosoma japonicum infections were 6.76% (202/2 990) and 2.86% (142/4 971) in humans and 0 (0/1 160) and 10.65% (31/291) in bovines in Deqiu and Baiyun villages of Nanjian County, respectively; however, no egg-positives were identified; in addition, there were 21.06 hm2 snail habitats found, but no S. japonicum infections were detected in snails. In 2019, there was 6.17 hm2 snail habitats detected, with 2.17% (245/11 298) occurrence of frames with snails and a 0.06 snails/0.1 m2 density of living snails; however, no positives for nucleic acid detection were seen in snails; among the 136 wild fecal samples captures from 23 settings, no S. japonicum infections were identified. CONCLUSIONS: The risk of schistosomiasis transmission remains at a low level in Nanjian County; however, the factors affecting the transmission of schistosomiasis have not been completed eliminated. The integrated schistosomiasis control strategy with an emphasis on the control of the source of S. japonicum infections requires to be reinforced to consolidate the control achievements.
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Medição de Risco , Esquistossomose/transmissão , Animais , Bovinos , China/epidemiologia , Cidades , Estudos Transversais , Fezes/parasitologia , Humanos , Contagem de Ovos de Parasitas , Estudos Retrospectivos , Caramujos/parasitologiaRESUMO
OBJECTIVE: To characterize a species of the genus Tricula and parasitized trematodes in schistosomiasis-endemic areas of Yunnan Province using a molecular analysis, so as to understand their taxonomic positions. METHODS: Tricula spp. and Oncomelania snails were collected from Xiangyun County, Yunnan Province, and cercaria parasitizing snails were observed using crushing followed by microscopy. Cercaria parasitizing Tricula snails at various morphologies were sampled using a shedding method. Genomic DNA was extracted from snail soft tissues and cercariae, and the 16S rRNA, COI, 28S rDNA genes in snails and the ND1 and 28S rDNA genes in cercariae were amplified using a PCR assay and sequenced. The species of Tricula snails and their parasitized trematodes was characterized using sequence alignment and phylogenetic analysis. RESULTS: Among 382 Tricula snails detected, there were three types of trematode cercariae found, including the non-forked (20.94%, 80/382), double-forked (3.40%, 13/382) and swallow shapes (7.07%, 27/382). Sequence and phylogenetic analyses showed that the 16S rRNA, COI and 28S rDNA gene sequences of this species of Tricula had high homology to those in Delavaya dianchiensis, and were clustered in a branch. Sequencing analysis of the ND1 and 28S rDNA genes revealed that the non-forked cercariae belonged to the family Pleu- rogenidae, the swallow-shaped cercariae belonged to the family Opecoelidae, and the double-forked cercariae belonged to another species of the genus Schistosoma that was different from S. sinensium and S. ovuncatum. CONCLUSIONS: The species and taxonomy of Triculla spp. and their parasitized trematodes are preliminarily determined in schistosomiasis-endemic areas of Yunnan Province; however, further studies are required to investigate the more definite taxonomy and pathogenicity.
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Cercárias , Filogenia , Caramujos/classificação , Caramujos/parasitologia , Trematódeos , Animais , Cercárias/genética , Cercárias/isolamento & purificação , China , Complexo IV da Cadeia de Transporte de Elétrons/genética , Doenças Endêmicas , NADH Desidrogenase/genética , RNA Ribossômico 16S/genética , RNA Ribossômico 28S/genética , Esquistossomose/epidemiologia , Esquistossomose/parasitologia , Caramujos/genética , Trematódeos/genética , Trematódeos/isolamento & purificaçãoRESUMO
The potential applications of perovskite manganite R1-xAxMnO3 (R = rare earth element; A = Sr, Ca) thin films have been continuously explored due to their multi-functional properties. In particular, the optimally hole-doped La0.67Ca0.33MnO3 thin film demonstrates a colossal magneto-resistance that is beneficial to the performance of spintronic devices. To understand the effect of R and A ions on the material properties, we systematically measure the resistivity, magnetization, and electronic energy states for three optimally hole-doped R0.67A0.33MnO3 thin films with R = La, Sm and A = Sr, Ca. Various energy parameters are derived based on the X-ray absorption and X-ray photoelectron spectra, including the band gap, the charge frustration energy and the magnetic exchange energy. It is interesting to find that the replacement of La with Sm is more effective than that of Sr with Ca in terms of tuning the electrical property, the Curie temperature, and the band gap. The strain-induced reduction of the O 2p- Mn 3d hybridization and the interplay of R/A site disorder and strain effect are discussed. The results of this study provide useful information for the band design of perovskite oxide films.
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We combined spectroscopic ellipsometry, Raman scattering spectroscopy, and first-principles calculations to explore the optical properties of YBaCuFeO5 single crystals. Measuring the optical absorption spectrum of YBaCuFeO5 at room temperature revealed a direct optical band gap at approximately 1.41 eV and five bands near 1.69, 2.47, 3.16, 4.26, and 5.54 eV. Based on first-principles calculations, the observed optical excitations were appropriately assigned. Analysis of the temperature dependence of the band gap indicated anomalies in antiferromagnetic phase transition at 455 and 175 K. Additionally, a hardening in the frequency of the Eg phonon mode was observed at 175 K. The value of the spin-phonon coupling constant was 15.7 mRy/Å2. These results suggest a complex nature of spin-charge-lattice interactions in YBaCuFeO5.
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This study probes the temperature-dependent strain that is strongly correlated with the orbital and magnetic structures of epitaxial films of Nd0.35Sr0.65MnO3 (NSMO) that are fabricated by pulsed laser deposition with two thicknesses, 17 (NS17) and 103 nm (NS103) on SrTiO3 (STO) substrate. This investigation is probed using X-ray diffraction (XRD) and absorption-based techniques, X-ray linear dichroism (XLD) and the X-ray magnetic circular dichroism (XMCD). XRD indicates a significant shift in the (004) peak position that is associated with larger strain in NS17 relative to that of NS103 at both 30 and 300 K. Experimental and atomic multiplet simulated temperature-dependent Mn L3,2-edge XLD results reveal that the stronger strain in a thinner NS17 film causes less splitting of Mn 3d eg state at low temperature, indicating an enhancement of orbital fluctuations in the band above the Fermi level. This greater Mn 3d orbital fluctuation can be the cause of both the enhanced ferromagnetism (FM) as a result of spin moments and the reduced Néel temperature of C-type antiferromagnetism (AFM) in NS17, leading to the FM coupling of the canted-antiferromagnetism (FM-cAFM) state in NSMO/STO epitaxial films at low temperature (T = 30 K). These findings are also confirmed by Mn L3,2-edge XMCD measurements.
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Temperature-dependent X-ray absorption near-edge structures, X-ray linear dichroism (XLD) and extended X-ray absorption fine structure (EXAFS) spectroscopic techniques were used to investigate the valence state, preferred orbital and local atomic structure that significantly affect the electrical and magnetic properties of a single crystal of YBaCuFeO5 (YBCFO). An onset of increase of resistivity at ~180 K, followed by a rapid increase at/below 125 K, is observed. An antiferromagnetic (AFM)-like transition is close to the temperature at which the resistivity starts to increase in the ab-plane and is also observed with strong anisotropy between the ab-plane and the c-axis. The XLD spectra at the Fe L3,2-edge revealed a change in Fe 3d eg holes from the preferential [Formula: see text] orbital at high temperature (300-150 K) to the [Formula: see text] orbital at/below 125 K. The analysis of the Fe K-edge EXAFS data of YBCFO further revealed an unusual increase in the Debye-Waller factor of the nearest-neighbor Fe-O bond length at/below 125 K, suggesting phonon-softening behavior, resulting in the breaking of lattice symmetry, particularly in the ab-plane of Fe-related square pyramids. These findings demonstrate a close correlation between electrical resistivity and coupling of the preferred Fe 3d orbital with lattice distortion of a single crystal of YBCFO.
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OBJECTIVE: The aim of this study was to investigate whether hypoxia in vivo can induce hypoxic pulmonary hypertension by inhibiting the activation of FGF2 by miR-203. MATERIALS AND METHODS: We established a rat model of hypoxic pulmonary hypertension (HPH), and measured the right ventricular systolic pressure (RVSP) and right ventricular hypertrophy (right ventricular hypertrophy index). The ventricular hypertrophy index (RVHI) was calculated and HE staining of the lung tissue of HPH rats was performed. We extracted pulmonary arterial smooth muscle cells (PASMCs) from rats and identified them by immunofluorescence assay. The expression of miR-203 in hypoxic PASMCs was detected by quantitative Real time-polymerase chain reaction (qRT-PCR). The proliferation and migration of PASMCs were detected by EDU (5-Ethynyl-2'-deoxyuridine), cell counting kit-8 (CCK-8) and scratch assay, respectively. Dual Luciferase reporting assay and Western blot were used to detect the binding of miR-203 and FGF2. RESULTS: The results of qRT-PCR showed that miR-203 expression in rat PASMCs was significantly lower than that in normoxia control group at 24 h and 48 h after hypoxic treatment. EDU, CCK8 and scratch test results showed that proliferation and migration ability of PASMCs were weakened after overexpression of miR-203, and vice versa. Dual Luciferase reporter gene assays and Western blot experiments showed that miR-203 could target and combine with FGF2 to inhibit its expression. In vivo experiments showed that low expression of FGF2 could lead to decreased RVSP and RVHI, decreased FGF2 protein levels, and decreased WT% and (PM+FM)% in hypoxia-treated rats. CONCLUSIONS: Hypoxia in vivo is involved in the development of HPH by inhibiting the activation of FGF2 by miR-203. Meanwhile, specific inhibition of FGF2 can reduce hypoxia-induced pulmonary hypertension and improve pulmonary vascular remodeling.
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Fator 2 de Crescimento de Fibroblastos/antagonistas & inibidores , Hipertensão Pulmonar/etiologia , Hipóxia/complicações , MicroRNAs/fisiologia , Animais , Células Cultivadas , Fator 2 de Crescimento de Fibroblastos/fisiologia , Masculino , Miócitos de Músculo Liso/fisiologia , Artéria Pulmonar/citologia , Ratos , Ratos Sprague-DawleyRESUMO
Essentials The pathogenesis of immune thrombocytopenia (ITP) has not been fully clarified. We analyzed the role of anti-αvß3 autoantibody in the pathogenesis of ITP in patients. Anti-αvß3 autoantibody impeded megakaryocyte migration and adhesion to the vascular niche. Anti-αv ß3 autoantibody potentially contributes to the pathogenesis of refractory ITP. SUMMARY: Background The pathogenesis of immune thrombocytopenia (ITP) has not been fully clarified. Anti-αvß3 integrin autoantibody is detected in chronic ITP patients, but its contribution to ITP is still unclear. Objectives To clarify the potential role of anti-αvß3 integrin autoantibody in chronic ITP and the related mechanism. Methods Relationship between levels of anti-αvß3 autoantibody and platelets in chronic ITP patients was evaluated. The influence of anti-αvß3 antibody on megakaryocyte (MK) survival, differentiation, migration and adhesion was assessed, and the associated signal pathways were investigated. Platelet recovery and MKs' distribution were observed in an ITP mouse model pretreated with different antibodies. Result In this study, we showed that the anti-αvß3 autoantibody usually coexists with anti-αIIbß3 autoantibody in chronic ITP patients, and patients with both autoantibodies have lower platelets. In in vitro studies, we showed that the anti-αvß3 antibody had no significant effect on the survival and proliferation of MKs, whereas it decreased formations of proplatelet significantly. Anti-αvß3 antibody impeded stromal cell derived facor-1 alpha (SDF-1α)- mediated migration and inhibited the phosphorylation of protein kinase B. Anti-αvß3 antibody significantly inhibited MKs' adhesion to endothelial cells and Fibrogen. The phosphorylation of focal adhesion kinase and proto-oncogene tyrosine-protein kinase Src induced by adhesion was inhibited when MKs were pretreated with anti-αvß3 antibody. In in vivo studies, we showed that injection with anti-αv antibody delayed platelet recovery in a mouse model of ITP. Conclusions These findings demonstrate that the autoantibody against integrin αv ß3 may aggravate thrombocytopenia in ITP patients by impeding MK migration and adhesion to the vascular niche, which provides new insights into the pathogenesis of ITP.
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Autoanticorpos/imunologia , Autoantígenos/imunologia , Integrina alfaVbeta3/imunologia , Megacariócitos/imunologia , Púrpura Trombocitopênica Idiopática/imunologia , Adolescente , Adulto , Idoso , Animais , Adesão Celular , Movimento Celular , Células Cultivadas , Quimiocina CXCL12/metabolismo , Células Endoteliais/metabolismo , Feminino , Sangue Fetal/citologia , Humanos , Masculino , Megacariócitos/citologia , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Fosforilação , Contagem de Plaquetas , Glicoproteína IIb da Membrana de Plaquetas/imunologia , Proteínas Quinases/metabolismo , Processamento de Proteína Pós-Traducional , Proto-Oncogene Mas , Proteínas Proto-Oncogênicas c-akt/metabolismo , Púrpura Trombocitopênica Idiopática/sangue , Células Estromais/metabolismo , Trombopoese , Adulto JovemRESUMO
This investigation reports on anisotropy in the magnetic interaction, lattice-orbital coupling and degree of phonon softening in single crystal Ni3TeO6 (NTO) using temperature- and polarization-dependent X-ray absorption spectroscopic techniques. The magnetic field-cooled and zero-field-cooled measurements and temperature-dependent Ni L3,2-edge X-ray magnetic circular dichroism spectra of NTO reveal a weak Ni-Ni ferromagnetic interaction close to ~60 K (TSO: temperature of the onset of spin ordering) with a net alignment of Ni spins (the uncompensated components of the Ni moments) along the crystallographic c-axis, which is absent from the ab-plane. Below the Néel temperature, TN~ 52 K, NTO is stable in the antiferromagnetic state with its spin axis parallel to the c-axis. The Ni L3,2-edge X-ray linear dichroism results indicate that above TSO, the Ni 3d eg electrons preferentially occupy the out-of-plane 3d3z2-r2 orbitals and switch to the in-plane 3dx2-y2 orbitals below TSO. The inherent distortion of the NiO6 octahedra and anisotropic nearest-neighbor Ni-O bond lengths between the c-axis and the ab-plane of NTO, followed by anomalous Debye-Waller factors and orbital-lattice in conjunction with spin-phonon couplings, stabilize the occupied out-of-plane (3d3z2-r2) and in-plane (3dx2-y2) Ni eg orbitals above and below TSO, respectively.
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OBJECTIVE: RLIP76 is a stress-responsive membrane protein regulating multiple cellular signaling pathways and is overexpressed in a number of malignant tumor cells. The aim of this study is to test whether the RLIP76 plays a critical role in cellular growth, apoptosis, cell cycle distribution and chemoresistance in melanoma. MATERIALS AND METHODS: In this study, human melanoma cell line A375 was stably transfected with an RLIP76-targeted shRNA-containing vector to investigate the role of RLIP76 in cellular function. Quantitative RT-PCR and Western blot revealed significant suppression of RLIP76 in A375 cells after transfection with shRNA-containing vector. Cell proliferation was determined by MTT assay. Wound scratch ad transwell assays were used for cell migration and invasion. RESULTS: The results showed that shRNA decreased the expression of RLIP76 in human melanoma cell line A375, and the knockdown of RLIP76 gene significantly inhibited A375 cell growth, resulted in G1 phase arrest and apoptosis increase of A375. Moreover, by testing the cell migratory and invasive abilities by wound scratch and transwell assays, it determined that the RLIP76 also suppressed cell migration and invasion in A375 cells and P13K/Akt signalling CONCLUSIONS: Overall, this study suggests that RLIP76 is a potential therapeutic target against melanoma.
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Transportadores de Cassetes de Ligação de ATP/genética , Proliferação de Células/genética , Proteínas Ativadoras de GTPase/genética , Melanoma/genética , Neoplasias Cutâneas/genética , Apoptose/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Inativação Gênica , HumanosRESUMO
X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T < T* in the (110) plane. These observations clearly suggest that the Ir 5d-derived states are closely related to the anomalous resistivity transition. Accordingly, a close relationship exists between local electronic and atomic structures and the CDW-like phase in the SIS single crystal.
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The local electronic and atomic structures of the high-quality single crystal of SrFeO3-δ (δ~0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of anisotropic resistivity in the ab-plane and along the c-axis close to the region of thermal hysteresis (near temperature for susceptibility maximum, Tm~78 K). All experiments herein were conducted during warming and cooling processes. The Fe L 3,2-edge X-ray linear dichroism results show that during cooling from room temperature to below the transition temperature, the unoccupied Fe 3d e g states remain in persistently out-of-plane 3d 3z2-r2 orbitals. In contrast, in the warming process below the transition temperature, they change from 3d 3z2-r2 to in-plane 3d x2-y2 orbitals. The nearest-neighbor (NN) Fe-O bond lengths also exhibit anisotropic behavior in the ab-plane and along the c-axis below Tm. The anisotropic NN Fe-O bond lengths and Debye-Waller factors stabilize the in-plane Fe 3d x2-y2 and out-of-plane 3d 3z2-r2 orbitals during warming and cooling, respectively. Additionally, a VB-PES study further confirms that a relative band gap opens at low temperature in both the ab-plane and along the c-axis, providing the clear evidence of the charge-density-wave nature of SrFeO3-δ (δ~0.19) single crystal.
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OBJECTIVE: To explore whether T lymphocytes subgroup, B lymphocytes, platelet antigen CD41a, CD61 or platelet antibodies are involved in the platelet transfusion refractoriness. METHODS: Forty-seven patients diagnosed as platelet transfusion refractoriness and 32 patients that achieved effective platelet therapy were ennolled in this study. Flow cytometry was performed to detect the proportion of cytotoxic T cell (CD3(+)CD4(-)CD8(+)), helper T cell (CD3(+)CD4(+)CD8(-)) and B lymphocytes (CD19 (+) ), and the expression of platelet glycoproteins, including CD41a and CD61, while platelet antibodies were also measured by solid-phase agglutination. RESULTS: The significant lower level of helper T cell (36.60% vs 48.53%), higher level of cytotoxic T cell (53.26% vs 44.02%) and lower cytotoxic/helper T cell ratio (0.85 vs 1.31) were observed in platelet refractoriness group when compared with effective platelet therapy group (P<0.05). However, the significant difference was not observed in B lymphocytes between the two group (3.02% vs 2.85%, P>0.05). Platelet glycoproteins CD41a and CD61 and antibodies were both expressed at high levels in platelet refractoriness group (88.10% vs 51.69%, 88.36% vs 51.83%, 85.37% vs 14.82%, respectively, P<0.05). CONCLUSIONS: Activation of cytotoxic T cells, suppression of helper T cells, higher expression level of platelet glycoproteins CD41a and CD61 as well as the development of anti-platelet antibodies are involved in the immunologic mechanism of platelet refractoriness.