Spin-selectivity effect of G-quadruplex DNA molecules.

Chirality-induced spin selectivity has been attracting extensive interest in recent years and is demonstrated in a variety of chiral molecules, all of which arise from inherent molecular chirality. Here, we first propose a theoretical model to study the spin-dependent electron transport along guanine-quadruplex (G4) DNA molecules, connected to two nonmagnetic electrodes, by considering the molecule-electrode contact and weak spin-orbit coupling. Our results indicate that the G4-DNA molecular junctions exhibit pronounced spin-selectivity effect, and the asymmetric contact-induced external chirality, instead of the inherent molecular chirality, dominates their spin filtration efficiency. Furthermore, the spin-selectivity effect is robust against the disorder and hold in a wide range of model parameters. These results could be checked by charge transport measurements and provide an alternative way to improve the spin-selectivity effect of chiral nanodevices.

Spin-dependent electron transport in protein-like single-helical molecules.

We report on a theoretical study of spin-dependent electron transport through single-helical molecules connected by two nonmagnetic electrodes, and explain the experiment of significant spin-selective phenomenon observed in α-helical protein and the contradictory results between the protein and single-stranded DNA. Our results reveal that the α-helical protein is an efficient spin filter and the spin polarization is robust against the disorder. These results are in excellent agreement with recent experiments [Mishra D, et al. (2013) Proc Natl Acad Sci USA 110(37):14872-14876; Göhler B, et al. (2011) Science 331(6019):894-897] and may facilitate engineering of chiral-based spintronic devices.

Thermal dissipation of the quantum spin Hall edge states in HgTe/CdTe quantum well.

Quantum spin Hall effect is characterized by topologically protected helical edge states. Here we study the thermal dissipation of helical edge states by considering two types of dissipation sources. The results show that the helical edge states are dissipationless for normal dissipation sources with or without Rashba spin-orbit coupling in the system, but they are dissipative for spin dissipation sources. Further studies on the energy distribution show that electrons with spin-up and spin-down are both in their own equilibrium without dissipation sources. Spin dissipation sources can couple the two subsystems together to induce voltage drop and non-equilibrium distribution, leading to thermal dissipation, while normal dissipation sources cannot. With the increase of thermal dissipation, the subsystems of electrons with spin-up and spin-down evolve from non-equilibrium finally to mutual equilibrium. In addition, the effects of disorder on thermal dissipation are also discussed. Our work provides clues to reduce thermal dissipation in the quantum spin Hall systems.

Enhanced electron transport and self-similarity in quasiperiodic borophene nanoribbons with line defects.

Recent experiments have revealed multiple borophene phases of distinct lattice structures, suggesting that the unit cells of ν1/6 and ν1/5 boron sheets, namely α and ß chains, serve as building blocks to assemble into novel borophene phases. Motivated by these experiments, we present a theoretical study of electron transport along two-terminal quasiperiodic borophene nanoribbons (BNRs), with the arrangement of the α and ß chains following the generalized Fibonacci sequence. Our results indicate that the energy spectrum of these quasiperiodic BNRs is multifractal and characterized by numerous transmission peaks. In contrast to the Fibonacci model that all the electronic states should be critical, both delocalized and critical states appear in the quasiperiodic BNRs, where the averaged resistance saturates at the inverse of one conductance quantum for the delocalized states in the large length limit and contrarily exhibits a power-law dependence on the nanoribbon length for the critical states. Besides, the self-similarity is observed from the transmission spectrum, where the conductance curves overlap at different energy regions of two quasiperiodic BNRs of different Fibonacci indices and the resistance curves are analogous to each other at different energy scales of a single quasiperiodic BNR. These results complement previous studies on quasiperiodic systems where the multifractal energy spectrum and the self-similarity are observed by generating quasiperiodic potential energies, suggesting that borophene may provide an intriguing platform for understanding the structure-property relationships and exploring the physical properties of quasiperiodic systems.

Spin-selective transport of electrons in DNA double helix.

The experiment that the high spin selectivity and the length-dependent spin polarization are observed in double-stranded DNA [Science 331, 894 (2011)], is elucidated by considering the combination of the spin-orbit coupling, the environment-induced dephasing, and the helical symmetry. We show that the spin polarization in double-stranded DNA is significant even in the case of weak spin-orbit coupling, while no spin polarization appears in single-stranded DNA. Furthermore, the underlying physical mechanism and the parameter dependence of the spin polarization are studied.

Molecular Characterization of a New Moniliformis sp. From a Plateau Zokor (Eospalax fontanierii baileyi) in China.

In the present study, a new species of the genus Moniliformis species is described taxonomically in the mitochondrial genomic context. The parasite was found in a plateau zokor captured in a high-altitude area of Xiahe County of Gansu Province, China. The mitochondrial (mt) genome length of this new species was 14,066 bp comprising 36 genes and 2 additional non-coding regions (SNR and LNR), without atp8. The molecular phylogeny inferred by the cytochrome c oxidase subunit I gene (cox1) and the18S ribosomal RNA gene (18S rDNA) sequences showed that the parasite as a sister species to other Moniliformis spp. and was named Moniliformis sp. XH-2020. The phylogeny of the concatenated amino acid sequences of the 12 protein-coding genes (PCGs) showed Moniliformis sp. XH-2020 in the same cluster as Macracanthorhynchus hirudinaceus and Oncicola luehei confirming the cox1 and 18S rDNA phylogenetic inference. In addition, the entire mt genome sequenced in this study represents the first in the order Moniliformida, providing molecular material for further study of the phylogeny of the class Archiacanthocephala. Moreover, the species of this class, use arthropods as intermediate hosts and mammals as definitive hosts and are agents of acanthocephaliasis, a zoonosis in humans. Therefore, this study not only expands the host range among potential wild animal hosts for Archiacanthocephalans which is of great ecological and evolutionary significance but also has important significance for the research of zoonotic parasitic diseases.

PCR-RFLP assay confirms the existence of different mitochondrial lineages of Taenia hydatigena including a possible geographically restricted group.

Taenia hydatigena is a widespread tapeworm of canids (primarily dogs) that causes cysticercosis in ruminants (domestic and wild) and manifests as depression and weakness secondary to various hepatic damages and sometimes mortality in young animals, although, commonly encountered cases are asymptomatic. In most taeniids, genetic polymorphism has been found to impact host preferences, distribution, disease epidemiology and management. Recently, we identified two main mitochondrial lineages of T. hydatigena in China, and here, we examined the mitochondrial nad4-nad5 genes of T. hydatigena from China, Nigeria, Pakistan and Sudan to assess the intraspecies variation of isolates from these countries and also the distribution of the distinct mitochondrial groups. In addition to China, haplogroup B variant was found in Pakistan, while haplogroup A demonstrated a widespread distribution. We then designed a PCR-restriction fragment length polymorphism (PCR-RFLP) assay using XmiI (AccI) and RsaI (AfaI) restriction enzymes to differentiate members of both haplogroups. This result provides more molecular evidence supporting the existence of distinct mitochondrial variants of T. hydatigena. The epidemiological significance of these different mitochondrial groups remains to be explored further. The current PCR-RFLP assay offers a useful molecular approach for investigating the genetic population structure of T. hydatigena in enzootic regions and in identifying/discriminating the different mitochondrial groups (haplogroups A and B).

Expansion of Cyclophyllidea Biodiversity in Rodents of Qinghai-Tibet Plateau and the "Out of Qinghai-Tibet Plateau" Hypothesis of Cyclophyllideans.

The Cyclophyllidea comprises the most species-rich order of tapeworms (Platyhelminthes, Cestoda) and includes species with some of the most severe health impact on wildlife, livestock, and humans. We collected seven Cyclophyllidea specimens from rodents in Qinghai-Tibet Plateau (QTP) and its surrounding mountain systems, of which four specimens in QTP were unsequenced, representing "putative new species." Their complete mitochondrial (mt) genomes were sequenced and annotated. Phylogenetic reconstruction of partial 28S rDNA, cox1 and nad1 datasets provided high bootstrap frequency support for the categorization of three "putative new species," assigning each, respectively, to the genera Mesocestoides, Paranoplocephala, and Mosgovoyia, and revealing that some species and families in these three datasets, which contain 291 species from nine families, may require taxonomic revision. The partial 18S rDNA phylogeny of 29 species from Taeniidae provided high bootstrap frequency support for the categorization of the "putative new species" in the genus Hydatigera. Combined with the current investigation, the other three known Taeniidae species found in this study were Taenia caixuepengi, T. crassiceps, and Versteria mustelae and may be widely distributed in western China. Estimates of divergence time based on cox1 + nad1 fragment and mt protein-coding genes (PCGs) showed that the differentiation rate of Cyclophyllidea species was strongly associated with the rate of change in the biogeographic scenarios, likely caused by the uplift of the QTP; i.e., species differentiation of Cyclophyllidea might be driven by host-parasite co-evolution caused by the uplift of QTP. We propose an "out of QTP" hypothesis for the radiation of these cyclophyllidean tapeworms.

Validation of the Chinese version of the Functional Performance Inventory Short Form in patients with chronic obstructive pulmonary disease.

AIMS AND OBJECTIVE: To determine the reliability and validity of the Chinese version of the Functional Performance Inventory Short Form (FPI-SF-C) in patients with chronic obstructive pulmonary disease in Beijing, China. BACKGROUND: The Functional Performance Inventory Short Form (FPI-SF) is a 32-item instrument designed to measure self-reported functional performance of patients with chronic obstructive pulmonary disease. This instrument had not been translated into Mandarin Chinese and tested for use in mainland China. DESIGN: Cross-sectional validation study with a two-week test of reproducibility. METHOD: The FPI-SF was translated using forward and backward translation procedures and administered to 108 stable chronic obstructive pulmonary disease patients from outpatient clinics of three hospitals in Beijing, China. Pulmonary function and six-minute walking distance (6-MWD) tests were performed on the same day or within one week before the FPI-SF-C completion. Thirty of the patients participated in the reproducibility assessment. RESULTS: Cronbach's alpha for the FPI-SF-C total score was 0·89; subscales ranged from 0·70 (Body Care)-0·89 (Spiritual activities). Test-retest reliability (intraclass correlation coefficient) was 0·93 with subscales ranging from 0·73 (Body Care)-0·96 (Household Maintenance). No ceiling or floor effects were observed for total FPI-SF-C score. Total scores correlated significantly (p<0·05) with 6-MWD (r=0·56), modified Medical Research Council Dyspnoea Scale (MMRC) (r=-0·55), BODE index (r=-0·47), forced expiratory volume in one second (FEV(1)) (r=0·41) and FEV(1) % of predicted (r=0·26) and differentiated patients based on GOLD rating of COPD severity (χ(2)=16·22, p<0·001). CONCLUSIONS: Results suggest the FPI-SF-C is a reliable and valid instrument for measuring functional performance in mainland Chinese patients with chronic obstructive pulmonary disease. Further psychometric testing in a wide range of subjects and an evaluation of its utility in clinical practice are warranted. RELEVANCE TO PRACTICE: The FPI-SF-C may be useful for understanding difficulties in functional performance and evaluating the effect of treatment in Chinese patients with chronic obstructive pulmonary disease.

Efficient Spin-Dependent Charge Transmission and Improved Enantioselective Discrimination Capability in Self-Assembled Chiral Coordinated Monolayers.

Spin-dependent charge transmission or the so-called chirality-induced spin selectivity (CISS) effect was demonstrated in self-assembled chiral coordinated monolayers. Distinct from the previous CISS phenomenon observed mainly on pure biomolecules, here we expanded this effect to the coordinated complex of chiral biomolecules and metal cations, specifically, cysteine-Cu2+-alanine (Cys/Cu/Ala), in which the complex itself was redox-active. However, the coordinated self-assembled monolayers of cysteine-Cu2+-cysteine did not show any spin-dependent effect. In addition, this phenomenon was explained by developing a theoretical model with spin-orbit coupling. The alanine molecules contributed to multiple transport pathways, leading to experimentally observable spin polarization. Finally, this CISS effect in Cys/Cu/Ala complex was demonstrated to amplify the sensing signal. The enantioselective discrimination efficiency could be improved by controlling the orientation of the external magnetic field.

[Reliability and validity of modified pulmonary functional status and dyspnea questionnaire in Chinese patients with chronic obstructive pulmonary disease].

OBJECTIVE: To determine the reliability and validity of the modified pulmonary functional status and dyspnea questionnaire (PFSDQ-M) Chinese version in patients with chronic obstructive pulmonary disease (COPD) at 2 hospitals in Beijing, China. METHODS: PFSDQ-M has three domains, i.e., change experienced by patient with activities or activity restriction (CA), dyspnea with activities (DA) and fatigue with activities (FA). Sixty-one patients with COPD in stable condition were assessed by interview with PFSDQ-M Chinese version, modified Medical Research Council dyspnea scale (MMRC), respectively, and underwent pulmonary function test (PFT) and 6-minute walking test (6MWT) on the same day or within one week before interview. RESULTS: Cronbach's alpha was 0.84, 0.85 and 0.89 for domains of CA, DA and FA of the PFSDQ-M, respectively. Scores of change in activities, dyspnea and fatigue with activities in patients of COPD correlated to their 6-minute walking distance (r = -0.39 to -0.50), FEV(1) (r = -0.28 to -0.36), FEV(1)/FVC (r = -0.27 to -0.37), FEV(1)% of predicted (r = -0.27 to -0.37), dyspnea score in MMRC (r = 0.59 to 0.66) and BODE index (r = 0.40 to 0.51), respectively (all P < 0.01). Degrees of restriction of activity, dyspnea and fatigue with activities varied significantly in patients with different severity of COPD (chi(2) = 7.35 to 15.21, P < 0.05, P < 0.01, respectively). CONCLUSIONS: Results of 61 patients with COPD interviewed with PFSDQ-M Chinese version suggest its good reliability and validity in discriminating patients with COPD of varied severity and stages.

[The clinical characteristics and treatment of community outbreaks of the new influenza A (H1N1) infection].

OBJECTIVE: To describe the clinical characteristics of 3 community outbreaks of the novel influenza A (H1N1), and to compare the treatment effects of the traditional Chinese medicine with or without Oseltamivir. METHOD: The clinical records of 234 patients in 3 community outbreaks of the novel influenza A (H1N1) infection in June (n = 56), August (n = 96) and October (n = 82) of 2009 were analyzed, and the treatment effects of the traditional Chinese medicine with or without Oseltamivir were evaluated. RESULTS: The baseline characteristics, including age, temperature, indices of blood tests, hepatic and renal functions were distributed evenly between the 2 treatment groups. The overall analysis suggested that there was no significant difference between the 2 treatment groups in the duration of clinical symptoms (P > 0.05), the duration of fever (P > 0.05), and the hospitalization days (P > 0.05). However, an analysis stratified by the temperature (≥ 39°C or < 39°C) suggested that patients treated by the traditional Chinese medicine with Oseltamivir tended to suffer a shorter duration of fever [40.5 (37.3, 42.0) vs 22.0 (10.5, 30.8) hr, P < 0.01) ] in the higher temperature group. CONCLUSIONS: The traditional Chinese medicine was equivalent to oseltamivir in treating patients with the novel influenza A (H1N1) infection with lower temperature (< 39°C). Oseltamivir was effective in shortening the duration of fever in patients with temperature higher than 39°C.

Neuroprotection of soyabean isoflavone co-administration with folic acid against beta-amyloid 1-40-induced neurotoxicity in rats.

Soya isoflavones (SIF) and folic acid (FA) both confer the biological properties of antioxidation; however, the mechanism of their antioxidant effect on nervous system development is unclear. Our purpose is to investigate the neuroprotective effects of SIF, FA or co-administration of SIF with FA against beta-amyloid 1-40 (Abeta1-40)-induced learning and memory impairment in rats. In the present study, the learning and memory ability of rats and the amount of amyloid-positive neurons in the cerebral cortex and hippocampal CA1 area were measured. The levels of total antioxidant capacity (T-AOC), glutathione (GSH) and glutathione peroxidase (GSH-Px) in serum and brain tissue were also measured. The results showed that intracerebroventricular administration of Abeta1-40 resulted in a dramatic prolongation of the escape latency; however, in the SIF, FA and SIF+FA treatment groups, the functional deficits of learning and memory were significantly improved. Moreover, after Abeta1-40 injection, the levels of T-AOC and GSH were profoundly decreased, suggesting a decline of antioxidant activity in the rats. However, intragastric pre-treatment with SIF, or FA, or SIF+FA resulted in a significant increase of antioxidative activity. SIF, or FA, or SIF+FA treatments also reversed the Abeta1-40-induced increase in the amount of amyloid-positive neurons. These results suggest that: (1) learning or memory impairment in experimental rats was caused by Abeta1-40, which is probably attributed to Abeta-induced oxidative damage and deposition of beta-amyloid peptides in the brain; (2) pre-administration of SIF and/or FA may prevent the pathological alterations caused by Abeta1-40 treatment and the neuroprotective effects of SIF and/or FA are indicated.

Development and evaluation of a questionnaire for measuring suboptimal health status in urban Chinese.

BACKGROUND: Suboptimal health status (SHS) is characterized by ambiguous health complaints, general weakness, and lack of vitality, and has become a new public health challenge in China. It is believed to be a subclinical, reversible stage of chronic disease. Studies of intervention and prognosis for SHS are expected to become increasingly important. Consequently, a reliable and valid instrument to assess SHS is essential. We developed and evaluated a questionnaire for measuring SHS in urban Chinese. METHODS: Focus group discussions and a literature review provided the basis for the development of the questionnaire. Questionnaire validity and reliability were evaluated in a small pilot study and in a larger cross-sectional study of 3000 individuals. Analyses included tests for reliability and internal consistency, exploratory and confirmatory factor analysis, and tests for discriminative ability and convergent validity. RESULTS: The final questionnaire included 25 items on SHS (SHSQ-25), and encompassed 5 subscales: fatigue, the cardiovascular system, the digestive tract, the immune system, and mental status. Overall, 2799 of 3000 participants completed the questionnaire (93.3%). Test-retest reliability coefficients of individual items ranged from 0.89 to 0.98. Item-subscale correlations ranged from 0.51 to 0.72, and Cronbach's alpha was 0.70 or higher for all subscales. Factor analysis established 5 distinct domains, as conceptualized in our model. One-way ANOVA showed statistically significant differences in scale scores between 3 occupation groups; these included total scores and subscores (P<0.01). The correlation between the SHS scores and experienced stress was statistically significant (r=0.57, P<0.001). CONCLUSIONS: The SHSQ-25 is a reliable and valid instrument for measuring sub-health status in urban Chinese.

Violation of the single-parameter scaling hypothesis in human chromosome 22 with charge transfer models.

We investigate transport properties of DNA sequences in human chromosome 22 and compare the results with those of a random artificial DNA sequence based on the single- and double-stranded charge transfer models. The statistical quantities, including the Hurst exponent, the distribution of Lyapunov exponent (LE), the central moments, and the scaling parameter, are numerically calculated by using the transfer-matrix approach. It is found that the existence of satellite DNA segments in human chromosome 22 could result in deviations from usual Gaussian distribution of LE. Our results suggest that the presence of the satellite DNA segments, together with the long-range correlations and the base-pairing correlations could lead to the violation of single-parameter scaling hypothesis which holds for the random artificial DNA sequence although the behaviors of the averaged LEs for both DNA sequences are similar. This provides a viewpoint to analyze differences between the genomic DNA sequences and the nonliving random ones on the basis of localization properties of wave functions in the sequences.

Reliability and validity of Chinese version of a tool to assess the quality of life in idiopathic pulmonary fibrosis in patients with interstitial lung disease.

OBJECTIVE: This paper aims to determine the reliability and validity of the Chinese version of a tool that assesses the quality of life in idiopathic pulmonary fibrosis (cATAQ-IPF) in patients with interstitial lung disease (ILD). METHODS: We used the process of scale introduction to establish cATAQ-IPF. The content validity of the scale was evaluated by six experts. A total of 92 patients with ILD completed the cATAQ-IPF, St. George's respiratory questionnaire (SGRQ), and The Medical Research Council dyspnoea scale at the baseline, and 15 patients completed cATAQ-IPF at the follow-up period 2 weeks later. Thus, yielding data were used to assess various psychometric properties of cATAQ-IPF. Intraclass correlation coefficient (ICC), Cronbach's α coefficient, content validity index (CVI), item-level CVI (I-CVI), Pearson's coefficients, criterion-relation validity, and known-group validity were used for data analysis. RESULTS: The cATAQ-IPF showed excellent test-retest reliability (ICC = 0.95), except for the therapy domain (Cronbach's α = 0.60) and acceptable internal consistency (Cronbach's α = 0.96 for the total). The scale-level CVI was 0.80, and the I-CVI was in the range of 0.78-1.00. The total cATAQ-IPF score was strongly correlated with the SGRQ total score (r = 0.71, P < 0.01). The cATAQ-IPF score of patients with ILD was 250.74 ±â€¯47.39, and that of patients with IPF was 287.90 ±â€¯22.56. Patients with IPF possessed considerable impairments in health-related quality of life according to the cATAQ-IPF score (t = 4.94, P < 0.01). CONCLUSIONS: The cATAQ-IPF is a reliable and valid instrument for the evaluation of quality of life of Chinese patients with various forms of ILD.

Enhancement of transport in DNA-like systems induced by backbone disorder.

We report a theoretical study highlighting the fundamental effects of backbone disorder which simulates the environmental complications on charge transport properties of biological and synthetic DNA molecules. Based on effective tight-binding models of duplex DNA, the Lyapunov coefficient and current-voltage characteristics are numerically calculated by varying the backbone disorder degree. In contrast to the localization picture that the conduction of duplex DNA becomes poorer when the backbone disorder degree is increased, we find that the backbone disorder can enhance the charge transport ability of the DNA molecules when the environment-induced disorder surpasses a critical value, giving rise to a semiconducting-metallic transition. The physical origin for this is traced back to the antiresonant effects. These results provide a scenario to interpret a variety of transport behaviors observed in DNA molecules and suggest perspectives for future experiments intending to control the charge transport through DNA-based nanodevices.

Long-range correlation and charge transfer efficiency in substitutional sequences of DNA molecules.

We address the relation between long-range correlations and coherent charge transfer in substitutional DNA sequences using the transfer matrix approach. The substitutional sequences exhibit long-range correlations and show good transmittivity in comparison with uncorrelated random ones. It is found that the charge transfer efficiency varies for different substitutional sequences and many will present electronic delocalization in the system. Further, the resistivity for substitutional sequences may range from decreasing with the length, length independence, or increasing with the length. The conduction mechanisms of various behaviors observed for these sequences are analyzed.

[Effects of xuefu zhuyu decoction on functions of vascular endothelium in patients with unstable angina pectoris].

OBJECTIVE: To evaluate the effects of Xuefu Zhuyu Decoction (XFZYD) on functions of vascular endothelium in patients with unstable angina pectoris (UAP). METHODS: Fifty patients with UAP were randomly divided into two groups: XFZYD-treated group with 32 cases and control group with 18 cases. The patients in the control group were given regular therapy, while the patients in the XFZYD-treated group were given XFZYD additionally on the basis of regular therapy. All patients in both groups were treated for 8 weeks. Then the contents of serum endothelin (ET), nitric oxide (NO), soluble vascular cell adhesive molecule-1 (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1) were examined by radioimmunoassay, enzymic method and enzyme-linked immunosorbent assay (ELISA) respectively. RESULTS: The total response rate in the XFZYD-treated group was 93.75%, which was significantly higher than 66.67% in the control group (P<0.05). The contents of serum ET, sVCAM-1 and sICAM-1 in the XFZYD-treated group were much lower than those in the control group (P<0.01), while the content of serum NO was obviously higher than that in the control group (P<0.01). CONCLUSION: XFZYD can improve the functions of vascular endothelium by lowering the levels of endothelium-derived contracting substances, enhancing the levels of endothelium-derived relaxing substances, and reducing the cell adhesions, and hence to raise the therapeutic effects on UAP.

Orbital Kondo effect in a parallel double quantum dot.

We construct a theoretical model to study the orbital Kondo effect in a parallel double quantum dot (DQD). Recently, pseudospin-resolved transport spectroscopy of the orbital Kondo effect in a DQD has been experimentally reported. The experiment revealed that when interdot tunneling is ignored, two and one Kondo peaks exist in the conductance-bias curve for pseudospin-non-resolved and pseudospin-resolved cases, respectively. Our theoretical studies reproduce this experimental result. We also investigate the case of all lead voltages being non-equal (the complete pseudospin-resolved case) and found that there are at most four Kondo peaks in the curve of the conductance versus the pseudospin splitting energy. When interdot tunneling is introduced, some new Kondo peaks and dips can emerge. Furthermore, the pseudospin transport and the pseudospin flipping current are also studied in the DQD system. Since the pseudospin transport is much easier to control and measure than the real spin transport, it can be used to study the physical phenomenon related to the spin transport.