Transformation of A1/A2 Astrocytes Participates in Brain Ischemic Tolerance Induced by Cerebral Ischemic Preconditioning via Inhibiting NDRG2.

Cerebral ischemic preconditioning (CIP) has been shown to improve brain ischemic tolerance against subsequent lethal ischemia. Reactive astrocytes play important roles in cerebral ischemia-reperfusion. Recent studies have shown that reactive astrocytes can be polarized into neurotoxic A1 phenotype (C3d) and neuroprotective A2 phenotype (S100A10). However, their role in CIP remains unclear. Here, we focused on the role of N-myc downstream-regulated gene 2 (NDRG2) in regulating the transformation of A1/A2 astrocytes and promoting to brain ischemic tolerance induced by CIP. A Sprague Dawley rat model of middle cerebral artery occlusion/reperfusion (MCAO/R) was used. Rats were divided into the following six groups: (1) sham group; (2) CIP group: left middle cerebral artery was blocked for 10 min; (3) MCAO/R group: left middle cerebral artery was blocked for 90 min; (4) CIP + MCAO/R group: CIP was performed 72 h before MCAO/R; (5) AAV-NDRG2 + CIP + MCAO/R group: adeno-associated virus (AAV) carrying NDRG2 was administered 14 days before CIP + MCAO/R; (6) AAV-Ctrl + CIP + MCAO/R group: empty control group. The rats were subjected to neurological evaluation 24 h after the above treatments, and then were sacrificed for 2, 3, 5-triphenyltetraolium chloride staining, thionin staining, immunofluorescence and western blot analysis. In CIP + MCAO/R group, the neurological deficit scores decreased, infarct volume reduced, and neuronal density increased compared with MCAO/R group. Notably, CIP significantly increased S100A10 expression and the number of S100A10+/GFAP+ cells, and also increased NDRG2 expression. MCAO/R significantly decreased S100A10 expression and the number of S100A10+/GFAP+ cells yet increased C3d expression and the number of C3d+/GFAP+ cells and NDRG2 expression, and these trends were reversed by CIP + MCAO/R. Furthermore, over-expression of NDRG2 before CIP + MCAO/R, the C3d expression and the number of C3d+/GFAP+ cells increased, while S100A10 expression and the number of S100A10+/GFAP+ cells decreased. Meanwhile, over-expression of NDRG2 blocked the CIP-induced brain ischemic tolerance. Taken together, these results suggest that CIP exerts neuroprotective effects against ischemic injury by suppressing A1 astrocyte polarization and promoting A2 astrocyte polarization via inhibiting NDRG2 expression.

ER-phagy Is Involved in the Degradation of Collagen I by IL-1ß in Human Amnion in Parturition.

The process of parturition is associated with inflammation within the uterine tissues, and IL-1ß is a key proinflammatory cytokine involved. Autophagy is emerging as an important pathway to remove redundant cellular components. However, it is not known whether IL-1ß employs the autophagy pathway to degrade collagen, thereby participating in membrane rupture at parturition. In this study, we investigated this issue in human amnion. Results showed that IL-1ß levels were significantly increased in human amnion obtained from deliveries with spontaneous labor and membrane rupture, which was accompanied by decreased abundance of COL1A1 and COL1A2 protein but not their mRNA, the two components of collagen I. Consistently, IL-1ß treatment of cultured primary human amnion fibroblasts reduced COL1A1 and COL1A2 protein but not their mRNA abundance along with increased abundance of autophagy activation markers, including the microtubule-associated protein L chain 3ß II/I ratio and autophagy-related 7 (ATG7) in the cells. The reduction in COL1A1 and COL1A2 protein abundance induced by IL-1ß could be blocked by the lysosome inhibitor chloroquine or small interfering RNA-mediated knockdown of ATG7 or ER-phagy receptor FAM134C, suggesting that FAM134C-mediated ER-phagy was involved in IL-1ß-induced reduction in COL1A1 and COL1A2 protein in amnion fibroblasts. Consistently, levels of L chain 3ß II/I ratio, ATG7, and FAM134C were significantly increased in human amnion obtained from deliveries with spontaneous labor and membrane rupture. Conclusively, increased IL-1ß abundance in human amnion may stimulate ER-phagy-mediated COL1A1 and COL1A2 protein degradation in amnion fibroblasts, thereby participating in membrane rupture at parturition.

ER-phagy Is Involved in the Degradation of Collagen I by IL-1ß in Human Amnion in Parturition.

The process of parturition is associated with inflammation within the uterine tissues, and IL-1ß is a key proinflammatory cytokine involved. Autophagy is emerging as an important pathway to remove redundant cellular components. However, it is not known whether IL-1ß employs the autophagy pathway to degrade collagen, thereby participating in membrane rupture at parturition. In this study, we investigated this issue in human amnion. Results showed that IL-1ß levels were significantly increased in human amnion obtained from deliveries with spontaneous labor and membrane rupture, which was accompanied by decreased abundance of COL1A1 and COL1A2 protein but not their mRNA, the two components of collagen I. Consistently, IL-1ß treatment of cultured primary human amnion fibroblasts reduced COL1A1 and COL1A2 protein but not their mRNA abundance along with increased abundance of autophagy activation markers, including the microtubule-associated protein L chain 3ß II/I ratio and autophagy-related 7 (ATG7) in the cells. The reduction in COL1A1 and COL1A2 protein abundance induced by IL-1ß could be blocked by the lysosome inhibitor chloroquine or small interfering RNA-mediated knockdown of ATG7 or ER-phagy receptor FAM134C, suggesting that FAM134C-mediated ER-phagy was involved in IL-1ß-induced reduction in COL1A1 and COL1A2 protein in amnion fibroblasts. Consistently, levels of L chain 3ß II/I ratio, ATG7, and FAM134C were significantly increased in human amnion obtained from deliveries with spontaneous labor and membrane rupture. Conclusively, increased IL-1ß abundance in human amnion may stimulate ER-phagy-mediated COL1A1 and COL1A2 protein degradation in amnion fibroblasts, thereby participating in membrane rupture at parturition.

[Establishment of comprehensive evaluation models of physical fitness of the elderly based on machine learning].

The present study aims to establish comprehensive evaluation models of physical fitness of the elderly based on machine learning, and provide an important basis to monitor the elderly's physique. Through stratified sampling, the elderly aged 60 years and above were selected from 10 communities in Nanchang City. The physical fitness of the elderly was measured by the comprehensive physical assessment scale based on our previous study. Fuzzy neural network (FNN), support vector machine (SVM) and random forest (RF) models for comprehensive physical evaluation of the elderly people in communities were constructed respectively. The accuracy, sensitivity and specificity of the comprehensive physical fitness evaluation models constructed by FNN, SVM and RF were above 0.85, 0.75 and 0.89, respectively, with the FNN model possessing the best prediction performance. FNN, RF and SVM models are valuable in the comprehensive evaluation and prediction of physical fitness, which can be used as tools to carry out physical evaluation of the elderly.

Identification Principle and Thought of "Medical Malpractice" Based on Theoretical Analysis.

At present, medical disputes are still widely-concerned social problems and occasionally evolve into severe social events. In the dispute settlement mechanism, forensic identification opinion is the important technical support. Due to the high professionalism and complexity of medicine, the identification of medical malpractice has become major and difficult problem in the identification. This paper systematically analyze the concept of medical malpractice and five legal theories of malpractice determination, pointing out that China's forensic identification of medical damage should be led by the theory of "medical standards", supplemented by "prudent patient" standard and strengthen "peer review" in form. At the same time, seven main identification principles should be followed in practice: (1) take "obligation of diagnosis and treatment" as the basic principle of medical malpractice identification; (2) take whether to fulfill the obligation of diagnosis and treatment corresponding to current medical level as the specific principle; (3) take diagnosis and treatment routine, norms and guidelines as the main basis; (4) the principle of "peer review"; (5) the principle of "the generality of medical emergency action"; (6) the principle of "notification-informed-consent"; (7) the principle of "review of complications". This paper also puts forward the corresponding identification ideas in view of the above principles, hoping this helps standardize medical damage forensic identification activities.

The automated processing algorithm to correct the test result of serum neuron-specific enolase affected by specimen hemolysis.

INTRODUCTION: Serum neuron-specific enolase (NSE) is an important tumor marker for small cell lung cancer and neuroblastoma. However, the test of serum NSE compromised by specimen hemolysis is presented as a falsely higher result, which seriously disturbs clinical decision. This study aimed to establish a solution integrated with laboratory information system to clear the bias from hemolysis on serum NSE test. METHODS: The reference range of serum hemolysis index (HI) was first established, and specimen hemolysis rate was compared between HI test and visual observation. NSE concentration in serum pool with normal HI was spiked with serial diluted lysates from red blood cells to deduce individual corrective equation. The agreement between individual corrective equation and original NSE test was assayed by Bland and Altman plots. RESULTS: The high HI existed in 32.6% of specimens from patients. The NSE median of hemolyzed specimens was significant higher than the baseline (p = 0.038), while the corrected NSE median had no difference compared with the baseline (p = 0.757). The mean difference of corrected NSE and initial NSE was 1.92%, the SD of difference was 5.23%, and furthermore, the difference was independent of tendency of HI (Spearman r = -0.069, p = 0.640). The 95% confidence interval of mean difference (from -8.33% to 12.17%) was less than the acceptable bias range (±20%). CONCLUSION: The agreement between individual correction equation and NSE assay was satisfied. Our automated processing algorithm for serum NSE could provide efficient management of posttest data and correct positive bias from specimen hemolysis.

Acute pancreatitis due to tacrolimus in kidney transplant and review of the literature.

WHAT IS KNOWN AND OBJECTIVE: The purpose of this case report is to increase the awareness of tacrolimus-induced acute pancreatitis in renal transplantation patients. CASE SUMMARY: We present a case of tacrolimus-induced acute pancreatitis with positive rechallenge. The 24-year-old male patient underwent kidney transplant and received immunosuppressive therapy with tacrolimus. On day 10 post-transplant, he presented with abdominal pain. A laboratory analysis showed elevated serum amylase and serum lipase levels. An abdominal computed tomography scan showed large-volume ascites and pelvic cavity effusion. These findings led to a diagnosis of acute pancreatitis. After tacrolimus was temporarily stopped and altered with cyclosporine, his symptoms decreased and he was restarted with tacrolimus. On day 61, laboratory tests again revealed significant elevations of serum amylase and serum lipase. A computed tomography scan of the abdomen showed increased pancreatic tail fluid collections. We excluded other possible causes and concluded that tacrolimus was the definite inducer of pancreatitis. The patient was switched from tacrolimus to cyclosporine again. Serum amylase and serum lipase were gradually decreased to normal, and he was discharged home with no relapse. WHAT IS NEW AND CONCLUSION: With the consideration of the wide use of tacrolimus, it is important that healthcare providers are aware of tacrolimus-induced acute pancreatitis. Future studies are needed to confirm and quantify the risk of tacrolimus-induced acute pancreatitis.

[Effects of 5-azacytidine on DNA methylation and index components in patchouliol-type Pogostemon cablin].

This study aims to explore the relationship of DNA methylation with the contents of the index components as well as the growth and development of Pogostemon cablin. The demethylation reagent 5-azacytidine(5-azaC) was used to treat the tissue culture seedlings of patchouliol-type P. cablin. High performance liquid chromatography was employed to evaluate the changes of DNA methy-lation in P. cablin, and GC-MS to detect the contents of index components in P.cablin. The agronomic characters of P.cablin were measured using the common methods. The results showcased that DNA methylation of P.cablin was significantly reduced by 5-azaC in a concentration-dependent manner. Thirty days after treatment with 5-azaC at different concentrations, the content of patchouli alcohol changed slightly; compared with that in the control group, the content of pogostone in 50 µmol·L~(-1) and 100 µmol·L~(-1) 5-azaC groups was significantly up-regulated. The 100 µmol·L~(-1) 5-azaC group had the largest differences in contents of pogostone and patchouli alcohol compared with the control group, followed by the 50 µmol·L~(-1) 5-azaC group. Ninety days after disinhibition, the content of pogostone in the treatment group was significantly increased and the content of patchouli alcohol was significantly decreased. In addition, 5-azaC significantly inhibited the growth and development of P.cablin in a dose-dependent manner. These results indicate that DNA methylation regulates the biosynthesis of the index components in patchouliol-type P.cablin and proper demethylation can directly promote the synthesis of pogostone and indirectly affect the accumulation of patchouli alcohol.

Identification of apoptosis-associated protein factors distinctly expressed in cigarette smoke condensate-exposed airway bronchial epithelial cells.

Smoking is associated with an increased risk of respiratory diseases, including lung cancer and asthma. However, the mechanisms or diagnostic markers for smoking-related diseases remain largely unknown. Here we investigated the role of cigarette smoke condensate (CSC) in the regulation of human bronchial epithelial cell (BEAS-2B) behavior. We found that exposure to CSC significantly inhibited BEAS-2B cell viability, impaired cell morphology, induced cell apoptosis, triggered oxidative damage, and promoted inflammatory response, which suggests a deleterious effect of CSC on bronchial epithelial cells. In addition, CSC markedly altered the expression of apoptosis-associated protein factors, including p21, soluble tumor necrosis factor receptor 1, and Fas ligand. In sum, our study identified a panel of novel protein factors that may mediate the actions of CSC on bronchial epithelial cells and have a predictive value for the development and progression of smoking-related diseases, thus providing insights into the development of potential diagnostic and therapeutic strategies against these diseases.

Thromboembolism and bleeding risk in atrial fibrillation ablation with uninterrupted anticoagulation between new oral anticoagulants and vitamin K antagonists: insights from an updated meta-analysis.

Cumulative reports comparing the efficacy and safety outcomes between uninterrupted NOACs and vitamin K antagonists (VKA) in AF ablation had been freshly published. This meta-analysis aimed at offering a more comprehensive evaluation between these two anticoagulants in uninterrupted strategy. We searched in PUBMED, EMBASE, and Cochrane Library (inception to June 10, 2019) for eligible studies. Fixed-effects model was preferred in pooled analysis if I2 < 50%. Publication bias was also evaluated. A total of 23 studies involving 12,725 individuals were analyzed in this literature. There were no difference between uninterrupted NOACs and VKA groups in incidence of Stroke/TIA (RR 0.98, 95% CI 0.54-1.77, P = 0.93, I2 = 0%), silent cerebral embolism (RR 1.09, 95% CI 0.82-1.43, P = 0.56, I2 = 0%), minor bleeding complication (RR 0.97, 95% CI 0.83-1.14, P = 0.73, I2 = 0%), cardiac tamponade (RR 0.95, 95% CI 0.63-1.42, P = 0.80, I2 = 0%). Uninterrupted NOACs was associated with significantly lower major bleeding incidence (RR 0.67, 95% CI 0.49-0.92, P = 0.01, I2 = 0%), pericardial effusion (RR 0.75, 95% CI 0.56-1.00, P = 0.048, I2 = 9%). In sub-analysis, no difference was found in all sub-analyses for Stroke/TIA while significant major bleeding risk reduction in uninterrupted NOACs was identified in the subgroup of CHA2DS2-VASc score ≥ 2 and target activated clotting time (ACT) > 300 s. In conclusions, uninterrupted NOACs was more effective than uninterrupted VKA in reducing major bleeding and pericardial effusion risk without increasing thromboembolism risk, and the benefits of uninterrupted NOACs on major bleeding complication could be more pronounced if CHA2DS2-VASc score ≥ 2 or target ACT > 300 s.

Electroacupuncture Improves Baroreflex and γ-Aminobutyric Acid Type B Receptor-Mediated Responses in the Nucleus Tractus Solitarii of Hypertensive Rats.

Electroacupuncture (EA) has been reported to benefit hypertension, but the underlying mechanisms are still unclear. We hypothesized that EA attenuates hypertension, in part, through modulation of γ-aminobutyric acid (GABA) receptor function in the nucleus tractus solitarii (NTS). In the present study, the long-term effect of EA on GABA receptor function and expression was examined in the NTS of two-kidney, one-clip (2K1C) renovascular hypertensive rats. EA (0.1-0.4 mA, 2 and 15 Hz) was applied at Zusanli (ST36) acupoints overlying the deep fibular nerve for 30 min once a day for two weeks. The results showed that long-term EA treatment improved blood pressure (BP) and markedly restored the baroreflex response in 2K1C hypertensive rats. The increased pressor and depressor responses to microinjection of GABAB receptor agonist and antagonist into the NTS in the hypertensive rats were blunted by the EA treatment. Moreover, EA treatment attenuated the increased GABAB receptor expression in the NTS of hypertensive rats. In contrast, EA had no significant effect on the GABAA receptor function and expression in the NTS of 2K1C hypertensive rats. These findings suggest that the beneficial effects of EA on renovascular hypertension may be through modulation of functional GABAB receptors in the NTS.

Tuning Band Structure of Cadmium Chalcogenide Nanoflake Arrays via Alloying for Efficient Photoelectrochemical Hydrogen Evolution.

Owing to their high extinction coefficient and moderate band gap, cadmium chalcogenides are known as common semiconductors for photoelectric conversion. Nevertheless, no ideal cadmium chalcogenide with proper band structure is available yet for photoelectrochemical hydrogen evolution. In this work, we modified the band structure of CdTe via alloying with Se to achieve a ternary compound (CdSe0.8Te0.2) with n-type conduction, a narrower band gap, and a more negative band position compared to those of CdSe and CdTe. This novel material exhibits strong light absorption over a wider spectrum range and generates more vigorous electrons for hydrogen reduction. As a result, a photoelectrode based on nanoflake arrays of the new material could achieve a photocurrent density 2 times that of its CdSe counterpart, outperforming similar materials previously reported in the literature. Moreover, the quick transfer of holes achieved in the novel material was found to depress photocorrosion processes, which led to improved long-term working stability.

Fast separation of flavonoids by supercritical fluid chromatography using a column packed with a sub-2 µm particle stationary phase.

The purpose of this study was to compare the effects of different chromatographic columns for the separation of seven flavonoids. Four different stationary phases are available, including bridged ethyl hybrid, BEH and the same hybrid phase modified with 2-ethylpyridine, CSH fluorophenyl, and HSS C18 SB. The analytes included calycosin, genistein, medicarpin, calycosin-7-O-ß-d-glucoside, formononetin, formononetin-7-O-ß-d-glucoside, and liquiritigenin. The CSH fluorophenyl column was determined to be the most suitable and provided the fastest separation within 17 min using gradient elution with carbon dioxide as the mobile phase and methanol as the co-solvent. Good peak shapes were obtained, and the values of the peak asymmetry were close to 1.0 for all of the flavonoids. The resolution was more than 1.41 for all of the separated peaks. Baseline separation on the optimal columns was achieved by changing the co-solvent type and adjusting the temperature and pressure. Quantitative performance was evaluated under optimized conditions, and method validation was accomplished. The validation parameters, such as linearity, sensitivity, precision, and accuracy, were satisfactory. Good repeatability of both peak area (relative standard deviation <1.02%) and retention time (relative standard deviation <0.88%) was observed. The optimized chromatographic methods were successfully used for the determination of seven flavonoids in Radix astragali. The sensitivity was sufficient for the analysis of real samples.

[Mechanism in growth inhibition of quercetin on human bladder cancer cell line].

To investigate the inhibitory mechanism of quercetin on growth of human bladder cancer cell line(BIU-87). BIU-87 cells were cultured in vitro, and co-cultured with varying concentrations of quercetin, and the anti-proliferative activity was determined by CCK-8 assay. Apoptosis of quercetin-induced BIU-87 cells and cell cycle were determined by flow cytometry analysis. Expressions of Bal-2 and Bal-xL, and related proteins in TAK1/JNK signal pathway were measured using Western blot analysis. After treatment with quercetin for 24 h and 48 h, the proliferation of BIU-87 cells was significantly suppressed in a dose-dependent manner according to CCK-8 assay(P<0.05). The flow cytometry analysis indicated that each group of quercetin leads to a significant higher percentage of apoptosis of BIU-87 cells than control group after treatment with quercetin for 24 h and 48 h; In G0/G1 period, cells reduced, while the amount of cells in G2/M period increased, and cells in S period remained the same amount. Expressions of Bal-2, Bal-xL, p-TAK1, p-MKK4/7, p-JNK decreased in BIU-87 cells after treatment with quercetin. Quercetin could inhibit the proliferation and promote the apoptosis of BIU-87 cells. The mechanism may be correlated with the inhibition of TAK1/JNK signaling pathway, which led to the further decrease in expressions of Bal-2 and Bal-xL.

Safety and Efficacy of Different Catheter Ablations for Atrial Fibrillation: A Systematic Review and Meta-Analysis.

BACKGROUND: Previous studies suggested that cryoballoon ablation had clinical benefits comparable to those of radiofrequency ablation. However, recently, some new catheters have been invented, and no universal consensus exists on which ablation is the optimal choice. The present systematic review and meta-analysis aimed to assess and compare the safety and efficacy of cryoballoon and radiofrequency ablation by synthesizing published trials. METHODS AND RESULTS: A systematic literature review was conducted searching Medline, PubMed, Embase, Cochrane Library, and so forth. All trials comparing cryoballoon and radiofrequency ablation were screened and included if inclusion criteria were met. A total of 40 eligible studies were identified, adding up to 11,395 patients. The follow-up period ranged from 3 months to 25 months. Overall analyses indicated that cryoballoon ablation could bring more benefit in procedural time (risk ratio [RR] = -0.39, 95% confidence interval [CI]: -0.62 to -0.15), atrial fibrillation (AF) recrudescence (RR = 0.82, 95% CI: 0.70-0.96), and major complications (RR = 0.74, 95% CI: 0.58-0.95) for patients with AF. For the subgroups, the first-generation cryoballoon significantly reduced procedural time and major complications, but it increased ablation time. The patients referred for the second-generation cryoballoon (CBA) seemed to receive more clinical benefit (procedural time, fluoroscopic time, ablation time, AF recrudescence) and fewer complications. Finally, multiparty catheter (MTCA) was found to significantly reduce procedural and fluoroscopic times with a high rate of AF recrudescence. CONCLUSIONS: The present systematic review and meta-analysis demonstrated that cryoballoon ablation was associated with greater freedom from AF, shorter procedural time, and lower rate of major complications, compared with radiofrequency ablation. Especially, CBA was more advantageous. However, MTCA seems promising for radiofrequency ablation.

[The effect of electrical stimulation of nucleus tractus solitarius on cardiac nociception and its spinal cord mechanism in rat].

OBJECTIVE: Examine the effect of electrical stimulation of nucleus tractus solitaries (NTS) on cardiac-somatic motor reflex (CMR) that induced by intrapericardial administration of capsaicin to clarify the spinal cord mechanism of NTS involved in cardiac nociception in rat. METHODS: SD rats were randomly divided into electrical stimulation, control, yohimbine and naloxone group and treated with elecetrical stimulation NTS alone, or with intrathecal injection of vehicle, saline, norepinephrine a2 receptors antagonist (yohimbine), opioid receptor antagonist (naloxone) respectively. RESULTS: Electrical stimulation of NTS (10, 20, 50 MA), the CMR response deceased in an intensity-dependent manner (P<0.05); intrathecal injection of vehicle, saline had no effect on the inhibition effect of electrical stimulation (P>0.05); intrathecal injection of yohimbine (20 microg, 50 microg) or naloxone (50 microg, 100 microg), reversed the inhibition effect of electrical stimulation (P<0.05); intrathecal injection of low dose of naloxone, the inhibition effect of electrical stimulation was potentiated. CONCLUSION: Electrical stimulation of NTS has inhibition effect on cardiac nociception, norepinephrine alpha2 receptors and opioid receptor in spinal cord involved in this descending inhibition, low dose of naloxone has synergetic effect with descending inhibition.

Tailoring lithiation behavior by interface and bandgap engineering at the nanoscale.

Controlling the transport of lithium (Li) ions and their reaction with electrodes is central in the design of Li-ion batteries for achieving high capacity, high rate, and long lifetime. The flexibility in composition and structure enabled by tailoring electrodes at the nanoscale could drastically change the ionic transport and help meet new levels of Li-ion battery performance. Here, we demonstrate that radial heterostructuring can completely suppress the commonly observed surface insertion of Li ions in all reported nanoscale systems to date and to exclusively induce axial lithiation along the [111] direction in a layer-by-layer fashion. The new lithiation behavior is achieved through the deposition of a conformal, epitaxial, and ultrathin silicon (Si) shell on germanium (Ge) nanowires, which creates an effective chemical potential barrier for Li ion diffusion through and reaction at the nanowire surface, allowing only axial lithiation and volume expansion. These results demonstrate for the first time that interface and bandgap engineering of electrochemical reactions can be utilized to control the nanoscale ionic transport/insertion paths and thus may be a new tool to define the electrochemical reactions in Li-ion batteries.

Two-phase electrochemical lithiation in amorphous silicon.

Lithium-ion batteries have revolutionized portable electronics and will be a key to electrifying transport vehicles and delivering renewable electricity. Amorphous silicon (a-Si) is being intensively studied as a high-capacity anode material for next-generation lithium-ion batteries. Its lithiation has been widely thought to occur through a single-phase mechanism with gentle Li profiles, thus offering a significant potential for mitigating pulverization and capacity fade. Here, we discover a surprising two-phase process of electrochemical lithiation in a-Si by using in situ transmission electron microscopy. The lithiation occurs by the movement of a sharp phase boundary between the a-Si reactant and an amorphous Li(x)Si (a-Li(x)Si, x ~ 2.5) product. Such a striking amorphous-amorphous interface exists until the remaining a-Si is consumed. Then a second step of lithiation sets in without a visible interface, resulting in the final product of a-Li(x)Si (x ~ 3.75). We show that the two-phase lithiation can be the fundamental mechanism underpinning the anomalous morphological change of microfabricated a-Si electrodes, i.e., from a disk shape to a dome shape. Our results represent a significant step toward the understanding of the electrochemically driven reaction and degradation in amorphous materials, which is critical to the development of microstructurally stable electrodes for high-performance lithium-ion batteries.

[Influence factors on the cryosurvival rate of post-thaw spermatozoa from sperm donors].

OBJECTIVE: To investigate the influence of seasons, blood types and semen parameters on the cryosurvival rate of frozen-thawed spermatozoa from sperm donors. METHODS: We retrospectively analyzed the influence of seasons, blood types, abstinence period, semen volume, sperm morphology, and pre-freeze sperm motility and concentration on the cryosurvival rate of frozen-thawed sperm in 4 088 semen samples from Shaanxi Human Sperm Bank. RESULTS: The cryosurvival rate of the post-thaw sperm was correlated negatively with the progressive motility of the pre-freeze sperm (r = -0.262, P < 0.01), but positively with pre-freeze sperm concentration (r = 0.247, P < 0.01), and it was significantly higher in the 6-day abstinence group ([70.2 +/- 5.4]%) than in the other abstinence groups (P < 0.01), so was it in the normal sperm morphology rate > 20% group ([71.4 +/- 5.1]%) than in the others (P < 0.01). The survival rate of the post-thaw sperm was not correlated with seasons, blood types, and semen volume (P > 0.05). CONCLUSION: Sperm motility, concentration and morphology and the abstinence period of sperm donors may be valuable predictors of the cryosurvival rate of post-thaw sperm, but no correlation was found between the survival rate and seasons, blood types and semen volume.

[Rapid recognition of common machine oils based on laser induced fluorescence].

A rapid recognition method of common engine oils, based on the principle of laser induced fluorescence (LIF), is proposed in the present paper. A 355 nm ultraviolet laser is used to induce fluorescence emission of 9 kinds of common machine oil samples. In total 450 groups of fluorescence spectral data are collected, of which 360 groups of data are used for classification training and 90 sets of data for identification. It was found that the fluorescence spectra of engine oils are distinct from each other visibly. The rapid identification of 90 groups of data is realized by using clustering analysis combined with principal component analysis. The recognition rate could reach up to 97.8%. Experiment demonstrated that the fast identification of diverse engine oils could be realized by using LIF combined with multivariate analysis method.