Epidural combined optical and electrical stimulation induces high-specificity activation of target muscles in spinal cord injured rats.

Introduction: Epidural electrical stimulation (EES) has been shown to improve motor dysfunction after spinal cord injury (SCI) by activating residual locomotor neural networks. However, the stimulation current often spreads excessively, leading to activation of non-target muscles and reducing the accuracy of stimulation regulation. Objectives: Near-infrared nerve stimulation (nINS) was combined with EES to explore its regulatory effect on lower limb muscle activity in spinal-cord-transected rats. Methods: In this study, stimulation electrodes were implanted into the rats' L3-L6 spinal cord segment with T8 cord transected. Firstly, a series of EES parameters (0.2-0.6 mA and 20-60 Hz) were tested to determine those that specifically regulate the tibialis anterior (TA) and medial gastrocnemius (MG). Subsequently, to determine the effect of combined optical and electrical stimulation, near-infrared laser with a wavelength of 808 nm was used to irradiate the L3-L6 spinal cord segment while EES was performed. The amplitude of electromyography (EMG), the specific activation intensity of the target muscle, and the minimum stimulus current intensity to induce joint movement (motor threshold) under a series of optical stimulation parameters (power: 0.0-2.0 W; pulse width: 0-10 ms) were investigated and analyzed. Results: EES stimulation with 40 Hz at the L3 and L6 spinal cord segments specifically activated TA and MG, respectively. High stimulation intensity (>2 × motor threshold) activated non-target muscles, while low stimulation frequency (<20 Hz) produced intermittent contraction. Compared to electrical stimulation alone (0.577 ± 0.081 mV), the combined stimulation strategy could induce stronger EMG amplitude of MG (1.426 ± 0.365 mV) after spinal cord injury (p < 0.01). The combined application of nINS effectively decreased the EES-induced motor threshold of MG (from 0.237 ± 0.001 mA to 0.166 ± 0.028 mA, p < 0.001). Additionally, the pulse width (PW) of nINS had a slight impact on the regulation of muscle activity. The EMG amplitude of MG only increased by ~70% (from 3.978 ± 0.240 mV to 6.753 ± 0.263 mV) when the PW increased by 10-fold (from 1 to 10 ms). Conclusion: The study demonstrates the feasibility of epidural combined electrical and optical stimulation for highly specific regulation of muscle activity after SCI, and provides a new strategy for improving motor dysfunction caused by SCI.

Different macaque brain network remodeling after spinal cord injury and NT3 treatment.

Graph theory-based analysis describes the brain as a complex network. Only a few studies have examined modular composition and functional connectivity (FC) between modules in patients with spinal cord injury (SCI). Little is known about the longitudinal changes in hubs and topological properties at the modular level after SCI and treatment. We analyzed differences in FC and nodal metrics reflecting modular interaction to investigate brain reorganization after SCI-induced compensation and neurotrophin-3 (NT3)-chitosan-induced regeneration. Mean inter-modular FC and participation coefficient of areas related to motor coordination were significantly higher in the treatment animals than in the SCI-only ones at the late stage. The magnocellular part of the red nucleus may reflect the best difference in brain reorganization after SCI and therapy. Treatment can enhance information flows between regions and promote the integration of motor functions to return to normal. These findings may reveal the information processing of disrupted network modules.

Generation of robust optical entanglement in cavity optomagnonics.

We propose a scheme to realize robust optical entanglement in cavity optomagnonics, where two optical whispering gallery modes (WGMs) couple to a magnon mode in a yttrium iron garnet (YIG) sphere. The beam-splitter-like and two-mode squeezing magnon-photon interactions can be realized simultaneously when the two optical WGMs are driven by external fields. Entanglement between the two optical modes is then generated via their coupling with magnons. By exploiting the destructive quantum interference between the bright modes of the interface, the effects of initial thermal occupations of magnons can be eliminated. Moreover, the excitation of the Bogoliubov dark mode is capable of protecting the optical entanglement from thermal heating effects. Therefore, the generated optical entanglement is robust against thermal noise and the requirement of cooling the magnon mode is relaxed. Our scheme may find applications in the study of magnon-based quantum information processing.

Study on the relationship between hydrodynamic conditions and arsenic content in Quaternary sediments.

Groundwater is susceptible to arsenic contamination by sediment with high arsenic content, which is the primary culprit of regional arsenic pollution and poisoning. To explore the influence of the change in hydrodynamic conditions caused by changes in the sedimentary environment over time on arsenic content in sediments during the Quaternary, the hydrodynamic characteristics and arsenic content enrichment of borehole sediments were studied in typical high-arsenic groundwater areas of the Jianghan-Dongting Basin, China. The regional hydrodynamic conditions represented by each borehole location were analyzed, the correlation between the variation in groundwater dynamics characteristics and arsenic content in different hydrodynamic periods was analyzed, and the relationship between arsenic content and grain size distribution was quantitatively investigated using grain size parameter calculation, elemental analysis, and statistical estimates of arsenic content in borehole sediments. We observed that the relationship between arsenic content and hydrodynamic conditions differed between sedimentary periods. Furthermore, arsenic content in the sediments from the borehole at Xinfei Village was significantly and positively correlated with a grain size of 127.0-240.0 µm. For the borehole at Wuai Village, arsenic content was significantly and positively correlated with a grain size of 1.38-9.82 µm size (at 0.05 level of significance). However, arsenic content was inversely correlated with grain sizes of 110.99-716.87 and 133.75-282.07 µm at p values of 0.05 and 0.01, respectively. For the borehole at Fuxing Water Works, arsenic content was significantly and positively correlated with a grain size of 409.6-655.0 µm size (at 0.05 level of significance). Arsenic tended to be enriched in transitional and turbidity facies sediments with normal corresponding hydrodynamic strength but poor sorting. Furthermore, continuous and stable sedimentary sequences were conducive to arsenic enrichment. Fine-grain sediments provided abundant potential adsorption sites for high-arsenic sediments, but finer particle size was not correlated with higher arsenic levels.

Rehabilitation Training after Spinal Cord Injury Affects Brain Structure and Function: From Mechanisms to Methods.

Spinal cord injury (SCI) is a serious neurological insult that disrupts the ascending and descending neural pathways between the peripheral nerves and the brain, leading to not only functional deficits in the injured area and below the level of the lesion but also morphological, structural, and functional reorganization of the brain. These changes introduce new challenges and uncertainties into the treatment of SCI. Rehabilitation training, a clinical intervention designed to promote functional recovery after spinal cord and brain injuries, has been reported to promote activation and functional reorganization of the cerebral cortex through multiple physiological mechanisms. In this review, we evaluate the potential mechanisms of exercise that affect the brain structure and function, as well as the rehabilitation training process for the brain after SCI. Additionally, we compare and discuss the principles, effects, and future directions of several rehabilitation training methods that facilitate cerebral cortex activation and recovery after SCI. Understanding the regulatory role of rehabilitation training at the supraspinal center is of great significance for clinicians to develop SCI treatment strategies and optimize rehabilitation plans.

Comparative transcriptomes of nine tissues for the Heilongjiang brown frog (Rana amurensis).

The Heilongjiang brown frog (Rana amurensis) is widely used in traditional Chinese medicine. In particular, the oviduct and skin have been developed into various health products. However, limited numbers of complete genomes of amphibian species have been reported, excluding the Heilongjiang brown frog. Here, the transcriptomes of 45 samples from the liver, spleen, heart, ovaries, thigh muscles, skin, oviduct, stomach and intestine of five Heilongjiang brown frog were reassembled and analyzed. A total of 1,085,532 unigenes with an average length of 676.6 bp and N50 of 722 bp were obtained. Comparative transcriptomics of different tissues detected tissue-specific expression. There were 3248 differentially expressed genes (DEGs) in the ovary, and the number of unique DEGs between the ovary and spleen was the largest. The results of DEGs enrichment showed there were many pathways and items related to protein synthesis and metabolism in the oviduct. The DEGs of the skin were enriched with many bacterial defense items, indicating that there were a large number of antimicrobial peptides in the skin. Thus, these were suitable as biological sources for the development and extraction of antimicrobial peptides. Through the assembly of transcriptome sequencing data and functional annotation of the Heilongjiang brown frog genome, this study provides reference materials for further exploring and utilizing functional gene resources of frogs and lays a foundation for medical research and the development of new products.

Dysregulation of Pseudogenes/lncRNA-Hsa-miR-1-3p-PAICS Pathway Promotes the Development of NSCLC.

Objective: Non-small cell lung cancer (NSCLC) explains about 80 percent of whole lung cancers, and its 5-year survival rate is impoverished, as when people are first diagnosed, 68% of whom are identified at a dangerous stage. The molecular mechanisms of NSCLC are still being explored. Methods: GSE18842 and GSE19804 were exerted to scan for diversely expressed genes (DEGs) in NSCLC, and then we used GEPIA for the validation of DEGs expression. The prognostic values were determined through Kaplan-Meier analysis. Three target prediction databases indicated potential microRNAs (miRNAs), while miRNet predicted hsa-miR-1-3p's upstream long non-coding RNAs (lncRNAs) and pseudogenes. UALCAN was utilized to identify the co-expressed genes of PAICS, while enrichment analysis on them was managed with Enrichr. Results: We initially found that the gene expression level of cyclin B1 (CCNB1), cyclin-dependent kinases1 (CDK1), and phosphoribosylaminoimidazole succinocarboxamide synthetase (PAICS) had a notable increase in NSCLC. We predicted 6, 10, and 7 microRNAs to target CCNB1, CDK1, and PAICS, respectively. Among miRNA-mRNA (microRNA-messenger RNA) pairs, we deduced that the hsa-miR-1-PAICS axis was the most potential one to inhibit the occurrence of NSCLC. We also noted that the hsa-miR-1-3p-PAICS axis participated in regulating the process of mitosis with mechanical functions. Moreover, we identified 5 pseudogenes and 33 long non-coding RNAs (lncRNAs) that might inhibit the hsa-miR-1-3p-PAICS axis in NSCLC. Conclusions: The pseudogene/lncRNA-hsa-miR-1-3p-PAICS is very important in NSCLC on the basis of this study, thus providing us with effective treatments and promising biomarkers for the diagnosis of NSCLC.

Intrauterine Growth Restriction Induces Adulthood Chronic Metabolic Disorder in Cardiac and Skeletal Muscles.

Objective: Although population-based studies of intrauterine growth restriction (IUGR) demonstrated a series of postnatal complications, several studies identified that IUGR could definitely cause dysfunction of metabolism of cardiac and skeletal muscles in the perinatal period and early life. However, it is still unknown if such metabolic alternation would remain for long term or not, and whether normal protein diet administration postnatally would protect the IUGR offsprings from a "catch-up growth" and be able to reverse the premature metabolic remodeling. Materials and Methods: We established an IUGR rat model with pregnant rats and a low-protein diet, and the developmental phenotypes had been carefully recorded. The cardiac and skeletal muscles had been collected to undergo RNA-seq. Results: According to a series of comparisons of transcriptomes among various developmental processes, programmed metabolic dysfunction and chronic inflammation activity had been identified by transcriptome sequencing in IUGR offsprings, even such rats presented a normal developmental curve or body weight after normal postnatal diet feeding. Conclusion: The data revealed that IUGR had a significant adverse impact on long-term cardiovascular function in rats, even they exhibit good nutritional status. So that, the fetal stage adverse events would encode the lifelong disease risk, which could hide in young age. This study remaindered that the research on long-term molecular changes is important, and only nutrition improvement would not totally reverse the damage of IUGR.

Comparative transcriptomes of three different skin sites for the Asiatic toad (Bufo gargarizans).

Toads release toxic dry secretions from glands in their skin. Toxin possesses a wide range of biological effects, but little is known about its specific gene expression pattern and regulatory mechanisms. The Asiatic toad (Bufo gargarizans) is widely used to produce toxin. Here, we explored the gene expression of 30 tissue samples from three different skin sites (parotoid gland, dorsal skin, and abdomen skin) of B. gargarizans. After de novo assembly, 783,130 unigenes with an average length of 489 bp (N50 = 556 bp) were obtained. A total of 9,248 significant differentially expressed genes (DEGs) were detected. There were 8,819 DEGs between the parotoid gland and abdomen skin and 1,299 DEGs between the dorsal skin and abdomen skin, while only 1,283 DEGs were obtained between the parotoid gland and dorsal skin. Through enrichment analysis, it was found that the detected differential gene expressions corresponded to the different functions of different skin sites. Our key findings were the genetic expression of toxin secretion, the protection function of skin, and the related genes such as HSD3B, Cyp2c, and CAT, LGALS9. In conclusion, we provide useful transcript resources to study the gene expression and gene function of B. gargarizans and other amphibians. The detected DEGs between different sites of the skin provided better insights into the genetic mechanisms of toxin secretion and the protection function of skin for amphibians.

Transcriptomic landscape of persistent diarrhoea in rhesus macaques and comparison with humans and mouse models with inflammatory bowel disease.

Diarrhoea is a widespread disease in captive rhesus macaques (Macaca mulatta) and a small proportion of individuals may experience persistent diarrhoea. Persistent diarrhoea can lead to a compromised immune system, intestinal inflammation and malnutrition. We analyzed the blood transcriptomes of 10 persistent diarrhoeal and 12 healthy rhesus macaques to investigate the gene expression differences between the two groups. We identified 330 DEGs between persistent diarrhoeal and healthy rhesus macaques. The 211 up-regulated DEGs in the diarrhoeal group were mainly enriched in immune-related and interleukin-related categories. Among them, three interleukin (IL) 18 related DEGs (IL18, IL18R1, and IL18BP) played important roles in actively regulating pro-inflammatory responses. Interestingly, the up- and down-regulated DEGs were both enriched in the same immune-related categories. Thus, we applied a new method to examine the distribution of DEGs in all child categories. We found that interleukin and T cell related categories were mainly occupied by up-regulated DEGs, while immunoglobulin production and B cell related categories were enriched by down-regulated DEGs. We also compared rhesus macaque DEGs with the DEGs of inflammatory bowel disease (IBD) humans and IBD mouse models and found that 30-40% of macaque DEGs were shared with IBD humans and mouse models. In conclusion, our results showed that there were significant immune differences between persistent diarrhoeal rhesus macaques and healthy macaques, which was similar to the expression differences in IBD patients and mouse models.

Sex-specific gene expression in the blood of four primates.

Blood is an important non-reproductive tissue, but little is known about the sex-specific gene expressions in the blood. Therefore, we investigated sex-specific gene expression differences in the blood tissues of four primates, rhesus macaques (Macaca mulatta), Tibetan macaques (M. thibetana), yellow baboons (Papio cynocephalus), and humans. We identified seven sex-specific differentially expressed genes (SDEGs) in each non-human primate and 31 SDEGs in humans. The four primates had only one common SDEG, MAP7D2. In humans, immune-related SDEGs were identified as up-regulated, but also down-regulated in females. We also found that most of the X-Y gene pairs had similar expression levels between species, except pair EIF1AY/EIF1AX. The expression level of X-Y gene pairs of rhesus and Tibetan macaques showed no significant differential expression levels, while humans had six significant XY-biased and three XX-biased X-Y gene pairs. Our observed sex differences in blood should increase understanding of sex differences in primate blood tissue.

Overexpression of RIPK4 Predicts Poor Prognosis and Promotes Metastasis in Ovarian Cancer.

This study was conducted to evaluate the prognostic value of receptor-interacting protein kinase 4 (RIPK4) in ovarian cancer (OC) and its role in tumorigenesis. RNA expression and the corresponding clinical data were obtained from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. The relationship between clinical-pathological characteristics and RIPK4 expression was analyzed using the Wilcoxon signed-rank test and logistic regression. The Cox regression and the Kaplan-Meier method were used to evaluate the relationship between clinicopathological features and overall survival (OS). Gene set enrichment analysis (GSEA) was performed using Molecular Signatures Database. Scratch assay, transwell assay, and cell transfection were used to verify the function of RIPK4. Overexpression of RIPK4 was associated with the stage of OC and distant metastasis. Survival analysis revealed that patients with OC and higher expression of RIPK4 had a poorer prognosis. Univariate and multivariate analyses indicated that high expression of RIPK4 was associated with poor OS, as well as age and stage of OC. The areas under the curve (AUC) at 1, 4, and 8 years were 0.737, 0.634, and 0.669, respectively, according to the established OS prediction model. GSEA revealed that adherens junction, cadherin binding, and Wnt signaling pathway were enriched in the high RIPK4 expression group. Cell transfection confirmed RIPK4 was involved in the Wnt signaling pathway. RIPK4 can act as a potential prognostic molecular marker for poor survival in OC. Moreover, RIPK4 is associated with tumor metastasis and implicated in the regulation of the Wnt signaling pathway.

Bone marrow stem cells therapy alleviates vascular injury in a chronic obstructive pulmonary disease­obstructive sleep apnea overlap syndrome rat model.

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are highly prevalent potential risk factors for systemic disease. Previous studies have reported that COPD and OSA are major independent risk factors for cardio­ or cerebrovascular diseases. The present study aimed to investigate the role of bone marrow mesenchymal stem cells (BMSCs) on vascular injury in a COPD­OSA overlap syndrome (OS) rat model. Rats were randomly divided into three groups: Sham, OS model and BMSC. BMSC localization in major organs was detected via confocal laser fluorescence microscopy, and the aortic tissue pathological changes and related genes were measured using hematoxylin & eosin and Masson staining. Genes associated with vascular endothelial cell injury, including endothelin 1, vascular cell adhesion molecule 1 and endothelial nitric oxide synthase, were detected via reverse transcription­quantitative PCR and western blotting. Apoptosis of vascular endothelial cells was detected using TUNEL and immunofluorescence assays. The endothelial cell marker CD31 in injured vessels was analyzed via immunohistochemistry. BMSCs migrated into the heart, liver, spleen, lung, kidney, brain and aorta in the OS model. The green fluorescence expression of BMSCs demonstrated the highest level in the lung, followed by the aorta. Aortic tissue had a more severe vascular injury and increased apoptosis in the model group compared with the BMSC group. Vascular endothelial cell apoptosis was decreased in the BMSC group compared with the model group. The findings suggested that BMSCs could repair vascular injury by inhibiting endothelial cell damage and apoptosis. These data provide a theoretical basis for the treatment of cardiovascular diseases caused by OS with BMSCs.

Clinical characteristics of 116 hospitalized patients with COVID-19 in Wuhan, China: a single-centered, retrospective, observational study.

BACKGROUND: A cluster of acute respiratory illness, now known as Corona Virus Disease 2019 (COVID-19) caused by 2019 novel coronavirus (SARS-CoV-2), has become a global pandemic. Aged population with cardiovascular diseases are more likely be to infected with SARS-CoV-2 and result in more severe outcomes and elevated case-fatality rate. Meanwhile, cardiovascular diseases have a high prevalence in the middle-aged and elderly population. However, despite of several researches in COVID-19, cardiovascular implications related to it still remains largely unclear. Therefore, a specific analysis in regard to cardiovascular implications of COVID-19 patients is in great need. METHODS: In this single-centered, retrospective, observational study, 116 patients with laboratory-confirmed COVID-19 were enrolled, who admitted to the General Hospital of Central Theater Command (Wuhan, China) from January 20 to March 8, 2020. The demographic data, underlying comorbidities, clinical symptoms and signs, laboratory findings, chest computed tomography, treatment measures, and outcome data were collected from electronic medical records. Data were compared between non-severe and severe cases. RESULTS: Of 116 hospitalized patients with COVID-19, the median age was 58.5 years (IQR, 47.0-69.0), and 36 (31.0%) were female. Hypertension (45 [38.8%]), diabetes (19 [16.4%]), and coronary heart disease (17 [14.7%]) were the most common coexisting conditions. Common symptoms included fever [99 (85.3%)], dry cough (61 [52.6%]), fatigue (60 [51.7%]), dyspnea (52 [44.8%]), anorexia (50 [43.1%]), and chest discomfort (50 [43.1%]). Local and/or bilateral patchy shadowing were the typical radiological findings on chest computed tomography. Lymphopenia (lymphocyte count, 1.0 × 109/L [IQR, 0.7-1.3]) was observed in 66 patients (56.9%), and elevated lactate dehydrogenase (245.5 U/L [IQR, 194.3-319.8]) in 69 patients (59.5%). Hypokalemia occurred in 24 (20.7%) patients. Compared with non-severe cases, severe cases were older (64.0 years [IQR, 53.0-76.0] vs 56.0 years [IQR, 37.0-64.0]), more likely to have comorbidities (35 [63.6%] vs 24 [39.3%]), and more likely to develop acute cardiac injury (19 [34.5%] vs 4 [6.6%]), acute heart failure (18 [32.7%] vs 3 [4.9%]), and ARDS (20 [36.4%] vs 0 [0%]). During hospitalization, the prevalence of new onset hypertension was significantly higher in severe patients (55.2% vs 19.0%) than in non-severe ones. CONCLUSIONS: In this single-centered, retrospective, observational study, we found that the infection of SARS-CoV-2 was more likely to occur in middle and aged population with cardiovascular comorbidities. Cardiovascular complications, including new onset hypertension and heart injury were common in severe patients with COVID-19. More detailed researches in cardiovascular involvement in COVID-19 are urgently needed to further understand the disease.

Effects of bone marrow­derived mesenchymal stem cell transplantation on chronic obstructive pulmonary disease/obstructive sleep apnea overlap syndrome in rats.

Bone marrow­derived mesenchymal stem cells (BMSCs) possess potential therapeutic properties for treating patients with chronic obstructive pulmonary disease (COPD), which is characterized by emphysema and obstructive sleep apnea (OSA). However, their effects on overlap syndrome (OS) remain unclear. We investigated the potential therapeutic effects and possible mechanisms of BMSC transplantation in OS rats. To generate the OS model in rats, the animals underwent daily exposure to cigarette smoke and intermittent hypoxia. BMSCs were intravenously injected into rats. At 4 weeks post­transplantation, the severity of emphysema was assessed by lung hematoxylin and eosin (H&E) staining. The levels of oxidative stress and the malondialdehyde (MDA) and superoxide dismutase (SOD) contents in serum and lung were detected. The apoptosis of alveolar septal cells was also detected by TUNEL assay. Finally, we determined the expression of CD31 and VWF in lung tissues by an immunohistochemical (IHC) assay. It was found that BMSCs were able to migrate to the injured lung and aorta tissues. In lung tissues, transplanted BMSCs, some of which had differentiated into endotheliocytes, were found in the alveolar walls. The mean linear intercept (MLI) and pathological scores were higher and the mean alveolar number (MAN) was lower in the OS group than these parameters in the control group. These values were significantly reduced in the OS+BMSC group compared to those in the OS group. The MDA content was decreased and SOD activity was increased in the OS+BMSC group compared to those in the OS group. The apoptotic index of alveolar wall cells in the OS group was higher than that in the OS+BMSC group. The expression levels of CD31 and VWF in alveolar wall cells in the OS group were lower than those in the OS+BMSC group. These results indicate that BMSCs may inhibit the progression of emphysema in the OS model by differentiating into endotheliocytes and suppressing the apoptosis of endotheliocytes and oxidative stress. There is a possibility that the release of growth factors and structural support may be a determinant for the regenerative effects observed following treatment with BMSCs.

[Characteristics of Ozone Background Concentration in Beijing from 2004 to 2015].

Based on the hourly O3 monitoring data from 2004 to 2015 of Beijing, a comprehensive discussion on the characteristics of O3 concentration at a background station Dingling in Beijing was conducted. The results showed that the annual concentration of O31h was increasing with a growth rate of 4.40 µg·m-3 while the annual concentration of O38h was decreasing with annual average rates of -1.0 µg·m-3 and -1.5 µg·m-3 from May to October in 2004 and 2015. Over the past 3 years, number of O38h severe pollution days increased significantly and the situation of O3 pollution in Beijing became more serious. O3 concentration reached its peak in June in a year and its diurnal peak concentration occurred at about 15:00-18:00 at Dingling station which was 101-1.56 times larger than that in the urban center of Beijing. In different years, the ozone peak concentration at Dingling Station was 1h later than that in the urban center from May to October in diurnal variation and the difference of peak concentration was significantly reduced in recent years, which on the one hand may be related to regional ozone pollution, on the other hand may be related to the expansion of Beijing's urbanization.

[Effects and possible mechanisms of mesenchymal stem cell transplantation on emphysema in rats].

OBJECTIVE: To explore the effects of transplanting bone marrow mesenehymal stem cells (MSCs) on emphysema in rats and elucidate the possible mechanisms. METHODS: A total of 24 female Sprague-Dawley rats were randomly divided randomly into 3 groups of control, emphysema and MSCs transplantation (n=8 each). The rat model of emphysema was established by 14-week exposure to cigarette smoking and then MSCs labeled with 4, 6-diamidino-2-phenylindole (DAPI) were injected into recipient rats of MSCs transplantation group via tail veins. At 2 and 4 weeks post-transplantation, engraftment and differentiation of MSCs was determined. At 8 weeks post-transplantation, lung fissure sections were prepared for examining the morphological alterations. The apoptosis of alveolar septal cells was assessed. And the levels of oxidative stress in sera and lung were detected. RESULTS: At 2 and 4 weeks post-transplantation, MSCs labeled with DAPI could be found in recipient lungs, some of which differentiated into type II alveolar epithelial cells. Mean linear intercept was higher in emphysema and MSCs transplantation groups than control group [(111 ± 23) and (90 ± 15) vs (74 ± 10) µm], mean alveolar numbers were lower than control group [(94 ± 22) and (125 ± 15) vs (159 ± 22)/mm²] (all P<0.05); mean linear intercept was higher and mean alveolar numbers were lower in emphysema group than MSCs transplantation group (both P<0.05). The apoptotic index of alveolar wall cells in emphysema group was higher than MSCs transplantation group [(13.5 ± 2.5)% vs (4.8 ± 0.7)%, P<0.05]. Malondialdehyde of sera and lung in emphysema and MSCs transplantation groups was higher than control group [(4.3 ± 0.8), (3.7 ± 0.4) vs (3.0 ± 0.4) nmol/ml, (5.4 ± 0.5), (4.8 ± 0.4) vs (4.2 ± 0.6) nmol/mg, all P<0.05]; malondialdehyde of sera and lung in emphysema group was higher than MSCs transplantation group (both P<0.05). Superoxide dismutase (SOD) of sera and lung in emphysema and MSCs transplantation groups was lower than control group [(8.7 ± 0.8), (9.6 ± 0.7) vs (10.5 ± 0.9) U/ml and (56.3 ± 13.4), (70.2 ± 11.0) vs (84.9 ± 13.0) U/mg, all P<0.05]; SOD of sera and lung in emphysema group was lower than MSCs transplantation group (both P<0.05). CONCLUSION: MSCs transplantation via tail vein may arrest the progression of emphysema in a cigarette-smoke-induced rat model of emphysema through a differentiation of injected MSCs into type II alveolar epithelial cells and down-regulations of apoptosis and oxidative stress.

Statistically preferred basis of an open quantum system: its relation to the eigenbasis of a renormalized self-Hamiltonian.

We study the problem of the basis of an open quantum system, under a quantum chaotic environment, which is preferred in view of its stationary reduced density matrix (RDM), that is, the basis in which the stationary RDM is diagonal. It is shown that, under an initial condition composed of sufficiently many energy eigenstates of the total system, such a basis is given by the eigenbasis of a renormalized self-Hamiltonian of the system, in the limit of large Hilbert space of the environment. Here, the renormalized self-Hamiltonian is given by the unperturbed self-Hamiltonian plus a certain average of the interaction Hamiltonian over the environmental degrees of freedom. Numerical simulations performed in two models, both with the kicked rotor as the environment, give results consistent with the above analytical predictions.

Preferred states of decoherence under intermediate system-environment coupling.

The notion that decoherence rapidly reduces a superposition state to an incoherent mixture implicitly adopts a special representation, namely, the representation of preferred (pointer) states (PS). For weak or strong system-envrionment interaction, the behavior of PS is well known. Via a simple dynamical model that simulates a two-level system interacting with few other degrees of freedom as its environment, it is shown that even for intermediate system-environment coupling, approximate PS may still emerge from the coherent quantum dynamics of the whole system in the absence of any thermal averaging. The found PS can also continuously deform to expected limits for weak or strong system-environment coupling. Computational results are also qualitatively explained. The findings should be useful towards further understanding of decoherence and quantum thermalization processes.

Semiclassical approach to survival probability at quantum phase transitions.

We study the decay of survival probability at quantum phase transitions with infinitely degenerate ground levels at critical points. For relatively long times, the semiclassical theory predicts power-law decay of the survival probability in systems with d=1 and exponential decay in systems with sufficiently large d, where d is the degrees of freedom of the classical counterpart of the system. The predictions are checked numerically in four models.