Pharmacologically significant constituents collectively responsible for anti-sepsis action of XueBiJing, a Chinese herb-based intravenous formulation

Sepsis, a life-threatening health issue, lacks effective medicine targeting the septic response. In China, treatment combining the intravenous herbal medicine XueBiJing with conventional procedures reduces the 28-day mortality of critically ill patients by modulating septic response. In this study, we identified the combined active constituents that are responsible for the XueBiJing's anti-sepsis action. Sepsis was induced in rats by cecal ligation and puncture (CLP). The compounds were identified based on their systemic exposure levels and anti-sepsis activities in CLP rats that were given an intravenous bolus dose of XueBiJing. Furthermore, the identified compounds in combination were assessed, by comparing with XueBiJing, for levels of primary therapeutic outcome, pharmacokinetic equivalence, and pharmacokinetic compatibility. We showed that a total of 12 XueBiJing compounds, unchanged or metabolized, circulated with significant systemic exposure in CLP rats that received XueBiJing. Among these compounds, hydroxysafflor yellow A, paeoniflorin, oxypaeoniflorin, albiflorin, senkyunolide I, and tanshinol displayed significant anti-sepsis activities, which involved regulating immune responses, inhibiting excessive inflammation, modulating hemostasis, and improving organ function. A combination of the six compounds, with the same respective doses as in XueBiJing, displayed percentage survival and systemic exposure in CLP rats similar to those by XueBiJing. Both the combination and XueBiJing showed high degrees of pharmacokinetic compatibility regarding interactions among the six active compounds and influences of other circulating XueBiJing compounds. The identification of XueBiJing's pharmacologically significant constituents supports the medicine's anti-sepsis use and provides insights into a polypharmacology-based approach to develop medicines for effective sepsis management.

Preparation of pH-responsive polyurethane nano micelles and their antibacterial application

Considering the differences in pH between bacterial infection microenvironment and normal tissues, a series of pH-responsive drug-release amphiphilic polyurethane copolymers (DPU-g-PEG) have been prepared in this work. Fourier transform infrared (FT-IR) spectroscopy and 1H NMR was selected to detect the structure of the condensed polymers. The DPU-g-PEG amphiphilic copolymers could form stable micelles with a hydrophilic shell of polyethylene glycol (PEG) and a hydrophobic core of polylactic acid (PLA). We loaded a model drug called triclosan onto DPU-g-PEG micelles and studied how pH affects their particle size, Zeta potential, and drug release performance. The results revealed that when exposed to acidic conditions, the surface potential of DPU-g-PEG micelles changed, the micelles' particle size increased, and the drug release performance was significantly enhanced. These results suggested that the micelles prepared in this study can release more antibacterial substances at sites of bacterial infection. Meanwhile, we also investigated the impact of different ratios of soft and hard segments on the properties of micelles, and the results showed that the pH responsiveness of micelles was strongest when the ratio of soft segments (PLLA diol + PEG 2000): 1,6-hexamethylene diisocyanate (HDI): 2,6-Bis-(2-hydroxy-ethyl)-pyrrolo[3,4-f]isoindole-1,3,5,7-tetraone (DMA) = 1: 1.2: 0.2. Furthermore, the results of inhibition zone test, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) all confirmed the antibacterial activity of triclosan-load DPU-g-PEG micelles. In conclusion, the DPU-g-PEG micelles produced in this study have the potential to be used as intelligent drug delivery systems in the biomedical field.

Strong ultrafast demagnetization due to the intraband transitions

Demagnetization in ferromagnetic transition metals driven by a femtosecond laser pulse is a fundamental problem in solid state physics, and its understanding is essential to the development of spintronic devices.Ab initiocalculation of time-dependent magnetic moment in the velocity gauge so far has not been successful in reproducing the large amount of demagnetization observed in experiments. In this work, we propose a method to incorporate intraband transitions within the velocity gauge through a convective derivative in the crystal momentum space. Our results for transition-element bulk crystals (bcc Fe, hcp Co and fcc Ni) based on the time-dependent quantum Liouville equation show a dramatic enhancement in the amount of demagnetization after the inclusion of an intraband term, in agreement with experiments. We also find that the effect of intraband transitions on each ferromagnetic material is distinctly different because of their band structure and spin property differences. Our finding has a far-reaching impact on understanding of ultrafast demagnetization.

Urolithin A ameliorates obesity-induced metabolic cardiomyopathy in mice via mitophagy activation

Metabolic cardiomyopathy (MC) is characterized by intracellular lipid accumulation and utilizing fatty acids as a foremost energy source, thereby leading to excess oxidative stress and mitochondrial dysfunction. There is no effective therapy available yet. In this study we investigated whether defective mitophagy contributed to MC and whether urolithin A (UA), a naturally occurring microflora-derived metabolite, could protect against MC in experimental obese mice. Mice were fed high fat diet for 20 weeks to establish a diet-induced obese model. We showed that mitochondrial autophagy or mitophagy was significantly downregulated in the heart of experimental obese mice. UA (50 mg·kg-1·d-1, for 4 weeks) markedly activated mitophagy and ameliorated MC in obese mice by gavage. In PA-challenged H9C2 cardiomyocytes, UA (5 μM) significantly increased autophagosomes and decreased autolysosomes. Furthermore, UA administration rescued PINK1/Parkin-dependent mitophagy and relieved mitochondrial defects in the heart of obese mice, which led to improving cardiac diastolic function and ameliorating cardiac remodelling. In PA-challenged primarily isolated cardiomyocytes, both application of mitophagy inhibitor Mdivi-1 (15 μM) and silencing of mitophagy gene Parkin blunted the myocardial protective effect of UA. In summary, our data suggest that restoration of mitophagy with UA ameliorates symptoms of MC, which highlights a therapeutic potential of UA in the treatment of MC.

Luteolin Attenuates Diabetic Myocardial Hypertrophy by Inhibiting Proteasome Activity

INTRODUCTION

Luteolin is a flavonoid polyphenolic compound exerting broad pharmacological and medicinal properties. Diabetes-related obesity increases the total blood volume and cardiac output and may increase the myocardial hypertrophy progression. However, the mechanism of luteolin in diabetic myocardial hypertrophy remains uncertain. Therefore, this study aimed to evaluate whether luteolin improved diabetic cardiomyopathy (DCM) by inhibiting the proteasome activity.

METHODS

Cardiomyopathy was induced in streptozotocin-treated diabetes mellitus (DM) and db/db mice. Luteolin (20 mg kg-1·day-1) was administrated via gavage for 12 weeks. In vitro, high glucose and high insulin (HGI, glucose at 25.5 mM and insulin at 0.1 µM) inducing primary neonatal rat cardiomyocytes (NRCMs) were treated with or without luteolin for 48 h. Echocardiography, reverse transcription quantitative polymerase chain reaction, histology, immunofluorescence, and Western blotting were conducted. Proteasome activities were also detected using a fluorescent peptide substrate.

RESULTS

Luteolin administration significantly prevented the onset of cardiac hypertrophy, fibrosis, and dysfunction in type 1 DM (T1DM) and type 2 DM (T2DM). Compared with DCM mice, luteolin groups showed lower serum triglyceride and total cholesterol levels. Furthermore, luteolin attenuated HGI-induced myocardial hypertrophy and reduced atrial natriuretic factor mRNA level in NRCMs. Proteasome activities were inhibited by luteolin in vitro. Luteolin also reduces the proteasome subunit levels (PSMB) 1, PSMB2, and PSMB5 of the 20S proteasome, as well as proteasome-regulated particles (Rpt) 1 and Rpt4 levels of 19S proteasome. Furthermore, luteolin treatment increased protein kinase B (AKT) and GSK-3α/β (inactivation of GSK-3) phosphorylation. The phosphorylation level of AMPK activity was also reversed after the treatment with luteolin in comparison with the HGI-treated group.

CONCLUSION

This study indicates that luteolin protected against DCM in mice, including T1DM and T2DM, by upregulating phosphorylated protein AMPK and AKT/GSK-3 pathways while decreasing the proteasome activity. These findings suggest that luteolin may be a potential therapeutic agent for DCM.

[Transmission characteristics and risk factors of household COVID-19 clusters caused by 2019-nCoV Omicron variant in Tianjin]

Objective: To understand the transmission characteristics and risk factors of household COVID-19 clusters caused by 2019-nCoV Omicron variant in Tianjin and provide evidence for COVID-19 prevention and control. Methods: Field epidemiological method was used to investigate the epidemiological characteristics of COVID-19 cases, and descriptive analysis was used to describe the epidemiological information. Results: A total of 430 cases were reported in this epidemic in Tianjin, in which 409 cases were included in this study. Among these cases, 70.90% (290/409) occurred in families. The family secondary attack rate was 33.64% The family secondary attack rate in age group 12-17 years (13.79%) was significantly lower than that in age group 18-49 years (36.48%), the OR was 0.378 (95%CI: 0.170-0.840). The logistic regression analysis showed that compared with centralized quarantine, the OR of the index cases found in closed-off/controlled areas and in home quarantine were 2.951 (95%CI:1.322-6.586) and 2.287 (95%CI:1.164-4.495), respectively, compared with the cases without sore throat, the OR of the index cases with sore throat was 3.003 (95%CI: 1.576-5.720), and compared with cases in families without completed COVID-19 vaccinations in all members, the OR of the cases in families with completed COVID-19 vaccinations in all members was 0.268 (95%CI: 0.132-0.552). Conclusions: The risk of household transmission of infection with Omicron variant was high. Detecting the index case in closed-off/controlled areas or in home quarantine and sore throat in index cases were the risk factors of the household transmission, completed COVID-19 vaccination was the protective factor.

Spin-phonon dispersion in magnetic materials

Microscopic coupling between the electron spin and the lattice vibration is responsible for an array of exotic properties from morphic effects in simple non magnets to magnetodielectric coupling in multiferroic spinels and hematites. Traditionally, a single spin-phonon coupling constant is used to characterize how effectively the lattice can affect the spin, but it is hardly enough to capture novel electromagnetic behaviors to the full extent. Here, we introduce a concept of spin-phonon dispersion to project the spin moment change along the phonon crystal momentum direction, so the entire spin change can be mapped out. Different from the phonon dispersion, the spin-phonon dispersion has both positive and negative frequency branches even in the equilibrium ground state, which correspond to the spin enhancement and spin reduction, respectively. Our study of bcc Fe and hcp Co reveals that the spin force matrix, that is, the second-order spatial derivative of spin moment, is similar to the vibrational force matrix, but its diagonal elements are smaller than the off-diagonal ones. This leads to the distinctive spin-phonon dispersion. The concept of spin-phonon dispersion expands the traditional Elliott-Yafet theory in nonmagnetic materials to the entire Brillouin zone in magnetic materials, thus opening the door to excited states in systems such as CoF₂and NiO, where a strong spin-lattice coupling is detected in the THz regime.

Rapid screening of monoclonal antibodies against porcine circovirus type 2 using colloidal gold-based paper test

A proof of concept for using paper test as a suitable method in the production of monoclonal antibodies (MAbs) is reported. The paper test which detects antibodies against porcine circovirus type 2 (PCV2) using colloidal gold-labelled capsid protein as the antigen probe was applied exclusively in the screening of anti-PCV2 MAbs. It allowed the detection of 118 single cell clones within 30 min using naked eyes. MAbs with specific binding to authentic epitopes on the virus were selected using a blocking strategy in which the antibody was pre-incubated with PCV2 viral sample before applying to the test paper. Five hybridomas secreting MAbs against the capsid protein were obtained, with only three of them capable of binding to PCV2. The results were validated and confirmed using enzyme-linked immunosorbent assay and immunofluorescence assay. The paper test is simple, rapid, and independent on professional technicians and proves to be an excellent approach for the screening of MAbs against specific targets.

Grain filling leads to backflow of surplus water from the maize grain to the cob and plant via the xylem

Rapid dehydration of maize grain is one of the main characteristics of cultivar selection for mechanical grain harvest; however, the dominant driving forces and mechanisms of grain dehydration before physiological maturity remain disputable and obscure. This study compared the grain moisture content and dehydration rate of coated treatment (no surface evaporation) and control grains. Meanwhile, the xylem-mobile dye was infused from stem and cob, and its movement was observed in cob, ear-stalk and stem xylem. The development dynamics of husk, grain and cob were analyzed to determine the mechanism of grain dehydration. The results showed that, from grain formation to 5-10 days before physiological maturity, the main driving force of grain dehydration of the early and middle-maturity maize cultivars was filling, followed by surface evaporation. In the dye movement experiment, the movement of the stem-infused xylem-mobile dye through the pedicel xylem was observed during but not after the grain formation period. Moreover, the cob-infused xylem-mobile dye moved to the ear- stalk and the stem via the xylem. There was a significantly positive correlation between grain filling rate and dehydration rate from grain formation to physiological maturity. According to these results, we proposed that in the grain dehydration phase driven by filling, the surplus water in the grain flows back to the cob via the pedicel xylem, of which some flowed back to the plant via the cob and ear- stalk xylem. This provides a new theoretical basis for selecting and breeding maize cultivars suitable for mechanical grain harvesting.

Novel assays for quality evaluation of XueBiJing: Quality variability of a Chinese herbal injection for sepsis management

XueBiJing is an intravenous five-herb injection used to treat sepsis in China. The study aimed to develop a liquid chromatography-tandem mass spectrometry (LC-MS/MS)- or liquid chromatography-ultraviolet (LC-UV)-based assay for quality evaluation of XueBiJing. Assay development involved identifying marker constituents to make the assay therapeutically relevant and building a reliable one-point calibrator for monitoring the various analytes in parallel. Nine marker constituents from the five herbs were selected based on XueBiJing's chemical composition, pharmacokinetics, and pharmacodynamics. A selectivity test (for “similarity of response”) was developed to identify and minimize interference by non-target constituents. Then, an intercept test was developed to fulfill “linearity through zero” for each analyte (absolute ratio of intercept to C response, <2%). Using the newly developed assays, we analyzed samples from 33 batches of XueBiJing, manufactured over three years, and found small batch-to-batch variability in contents of the marker constituents (4.1%–14.8%), except for senkyunolide I (26.5%).

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To make assays therapeutically relevant, criteria were proposed for defining herbal medicine efficacy & selecting analytes.

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Two tests were developed to build a one-point assay calibrator for the simultaneous monitoring of various analytes.

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Variability among 3-year batches of XueBiJing was evaluated for the first time using the therapeutically relevant assays.

Pedicle complex tissue flap transfer for reconstruction of duplicated thumbs with unequal size

BACKGROUND

Thumb polydactyly is one of the most common congenital hand deformities, and the Bilhaut-Cloquet procedure or a modified one is often used. However, controversy remains over the rare instances in which both thumbs are not of similar length or far apart in distance.

AIM

To evaluate the clinical outcomes of pedicle complex tissue flap transfer in the treatment of duplicated thumbs with unequal size.

METHODS

From January 2014 to December 2020, 15 patients underwent duplicated thumb reconstruction by pedicle complex tissue flap transfer at our hand surgery center. The technique was used when it was necessary to combine different tissues from both severed and preserved thumbs that were not of similar length or far apart in distance. Subjective parents’ evaluations and functional outcomes (ALURRA and TATA criteria) were obtained. The alignment deviation, instability, range of motion (percent of opposite thumb) of the interphalangeal and metacarpophalangeal joints, and the aesthetic aspects, including circumference, length, nail size, and nail deformity, were used to assess the clinical outcomes.

RESULTS

The average age of patients at the time of surgery was 13 mo, and the mean final follow-up occurred at 42 mo. An appropriate volume with a stable joint and good appearance was obtained in 14 reconstructed thumbs. An unstable interphalangeal joint occurred in one thumb. The flexion-extension arc at the metacarpophalangeal joint was good, while that at the interphalangeal joint was poor. Most of the parents were satisfied with the cosmetic and functional results of the reconstructed thumbs. The mean ALURRA score was 21.8 (range: 20-24), and the Tada score was 6.9 (range: 5-8). Compared with the non-operated side, the length of the operated thumb was approximately 95%, the girth was 89%, and the nail width was 82.9%. The mean ranges of motion were 62.1% of that of the unaffected thumb in the interphalangeal joint and 78.3% in the metacarpophalangeal joint.

CONCLUSION

Harvesting a pedicle flap from a severed thumb is a safe and reliable procedure. Defects of the preserved thumb, such as the skin, nail, and bone, can be effectively restored using the complex tissue flap.

Zonisamide alleviates cardiac hypertrophy in rats by increasing Hrd1 expression and inhibiting endoplasmic reticulum stress

Antiepileptic drug zonisamide has been shown to be curative for Parkinson's disease (PD) through increasing HMG-CoA reductase degradation protein 1 (Hrd1) level and mitigating endoplasmic reticulum (ER) stress. Hrd1 is an ER-transmembrane E3 ubiquitin ligase, which is involved in cardiac dysfunction and cardiac hypertrophy in a mouse model of pressure overload. In this study, we investigated whether zonisamide alleviated cardiac hypertrophy in rats by increasing Hrd1 expression and inhibiting ER stress. The beneficial effects of zonisamide were assessed in two experimental models of cardiac hypertrophy: in rats subjected to abdominal aorta constriction (AAC) and treated with zonisamide (14, 28, 56 mg · kg-1 · d-1, i.g.) for 6 weeks as well as in neonatal rat cardiomyocytes (NRCMs) co-treated with Ang II (10 μM) and zonisamide (0.3 μM). Echocardiography analysis revealed that zonsiamide treatment significantly improved cardiac function in AAC rats. We found that zonsiamide treatment significantly attenuated cardiac hypertrophy and fibrosis, and suppressed apoptosis and ER stress in the hearts of AAC rats and in Ang II-treated NRCMs. Importantly, zonisamide markedly increased the expression of Hrd1 in the hearts of AAC rats and in Ang II-treated NRCMs. Furthermore, we demonstrated that zonisamide accelerated ER-associated protein degradation (ERAD) in Ang II-treated NRCMs; knockdown of Hrd1 abrogated the inhibitory effects of zonisamide on ER stress and cardiac hypertrophy. Taken together, our results demonstrate that zonisamide is effective in preserving heart structure and function in the experimental models of pathological cardiac hypertrophy. Zonisamide increases Hrd1 expression, thus preventing cardiac hypertrophy and improving the cardiac function of AAC rats.

Zonisamide, an antiepileptic drug, alleviates diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress

Endoplasmic reticulum stress (ER stress) plays a key role in the development of cardiac hypertrophy and diabetic cardiomyopathy (DCM). Zonisamide (ZNS) was originally developed as an antiepileptic drug. Studies have shown that ZNS suppresses ER stress-induced neuronal cell damage in the experimental models of Parkinson's disease. Herein, we investigated whether ZNS improved DCM by attenuating ER stress-induced apoptosis. C57BL/6J mice were fed with high-fat diet (HFD) and intraperitoneally injected with low-dose streptozotocin (STZ) to induce type 2 diabetes mellitus (T2DM), and then treated with ZNS (40 mg·kg-1·d-1, i.g.) for 16 weeks. We showed that ZNS administration slightly ameliorated the blood glucose levels, but significantly alleviated diabetes-induced cardiac dysfunction and hypertrophy. Furthermore, ZNS administration significantly inhibited the Bax and caspase-3 activity, upregulated Bcl-2 activity, and decreased the proportion of TUNEL-positive cells in heart tissues. We analyzed the hallmarks of ER stress in heart tissues, and revealed that ZNS administration significantly decreased the protein levels of GRP78, XBP-1s, ATF6, PERK, ATF4, and CHOP, and elevated Hrd1 protein. In high glucose (HG)-treated primary cardiomyocytes, application of ZNS (3 μM) significantly alleviated HG-induced cardiomyocyte hypertrophy and apoptosis. ZNS application also suppressed activated ER stress in HG-treated cardiomyocytes. Moreover, preapplication of the specific ER stress inducer tunicamycin (10 ng/mL) eliminated the protective effects of ZNS against HG-induced cardiac hypertrophy and ER stress-mediated apoptosis. Our findings suggest that ZNS improves the cardiac diastolic function in diabetic mice and prevents T2DM-induced cardiac hypertrophy by attenuating ER stress-mediated apoptosis.

Assessment of hepatic fat content in using quantitative ultrasound measurement of hepatic/renal ratio and hepatic echo-intensity attenuation rate

AIMS

This study aims to evaluate and validate a simple quantitative ultrasound (US) method for determining the hepatic fat content (HFC) based on the combination of quantitative US hepatic/renal ratio (US-HRR) and quantitative US hepatic echo-intensity attenuation rate (US-HAR) as compared with [1H]-magnetic resonance spectroscopy (1H-MRS).

MATERIAL AND METHODS

There were a total of 242 subjects recruited in the present study. All subjects were examined for HFC by quantitative US and 1H-MRS methods. The QUS-HRR and QUS-HAR were calculated from ordinary ultrasound images of liver and kidney with a triple modality 3D abdominal phantom using the Image J software.

RESULTS

The results found that US-HRR and US-HAR correlated with 1H-MRS HFC (US-HRR: r=0.946, p<0.001; US-HAR: r=0.936, p<0.001). The equation for HFC prediction by using quantitative US was: HFC (%) = 28.965 × US-HRR + 218.045 × US-HAR - 8.892. Subgroup analysis in study subjects with body mass index (BMI) ≥28 showed that quantitative US HFC was associated with 1H-MRS HFC (R2=0.953, p<0.001). Receiver operating characteristic (ROC) analysis observed that the cut-off value of fatty liver diagnosis was 6.71% in using the quantitative US model; the sensitivity and specificity for fatty liver diagnosis were 94.15% and 96.30%, respectively. Variability analysis indicated that there was a relative high degree of consistency in the measurement of HFC with different operators or ultrasonic apparatus.

CONCLUSIONS

Quantitative US measurement could be regarded as a simple, sensitive tool to accurately assess HFC. It provides a valid alternative to 1H-MRS as an easy, non-invasive option for the precise estimation of HFC in clinical practice.

[Seroepidemiological survey and influencing factors of hepatitis E virus infection among key occupational population in Tianjin]

Objective: To evaluate the infection rate and influencing factors of hepatitis E virus (HEV) among key occupational population in Tianjin, so as to help occupational population to carry out HEV prevention and control. Methods: A combination of stratified random sampling and convenience sampling was carried out for the study in Tianjin in June 2019. The livestock and poultry-related farming workers, slaughtering workers, selling workers, doctors, farmers, seafood sellers, sewage pipeline workers as the key occupational population groups (1036 person) , and non key occupational population as the control group (200 person) , cross-sectional surveys were conducted in the groups. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum IgG and IgM antibodies to HEV, and logistic regression model was used to analyze the influencing factors of HEV infection. Results: The positive rate of anti-HEV IgG in key occupational group was 26.45% (274/1036) , which was higher than that in control group of 14.50% (29/200) (χ(2)=13.41, P<0.01) . The occupations with the highest positive rate of anti-HEV IgG were livestock (swine) , breeding and slaughtering workers, all of which reached 33.96% (18/53) . The difference in infection rates between different occupations was statistically significant (χ(2)=22.57, P<0.01) . Multivariate logistic regression analysis showed that the longer working years, high frequency of eating out (3-5, ≥6 times/week) , drinking raw water, eating under-cooked pork or pig liver, and low frequency of washing hands were risk factors for HEV infection in occupational population (P<0.05) . But the high education is a protective factor for HEV infection (P<0.05) . Conclusion: There is a high positive rate of anti-HEV IgG in key occupational population in Tianjin. It is necessary to strengthen the monitoring, publicity and education of the high-risk population, pay attention to personal and dietary hygiene.

Ubc9 Attenuates Myocardial Ischemic Injury Through Accelerating Autophagic Flux

Aims

SUMOylation is a post-translational modification that plays a crucial role in the cellular stress response. We aimed to demonstrate whether and how the SUMO E2 conjugation enzyme Ubc9 affects acute myocardial ischemic (MI) injury.

Methods and Results

Adenovirus expressing Ubc9 was administrated by multipoint injection in the border zone of heart immediately after MI in C57BL/6 mice. Neonatal rat cardiomyocytes (NRCMs) were also infected, followed by oxygen and glucose deprivation (OGD). In vivo, Ubc9 adenovirus-injected mice showed decreased cardiomyocyte apoptosis, reduced myocardial fibrosis, and improved cardiac function post-MI. In vitro, overexpression of Ubc9 decreased cardiomyocyte apoptosis, whereas silence of Ubc9 showed the opposite results during OGD. We next found that Ubc9 significantly decreased the accumulation of autophagy marker p62/SQSTM, while the LC3 II level hardly changed. When in the presence of bafilomycin A1 (BAF), the Ubc9 adenovirus plus OGD group presented a higher level of LC3 II and GFP-LC3 puncta than the OGD group. Moreover, the Ubc9 adenovirus group displayed increased numbers of yellow plus red puncta and a rising ratio of red to yellow puncta on the mRFP-GFP-LC3 fluorescence assay, indicating that Ubc9 induces an acceleration of autophagic flux from activation to degradation. Mechanistically, Ubc9 upregulated SUMOylation of the core proteins Vps34 and Beclin1 in the class III phosphatidylinositol 3-kinase (PI3K-III) complexes and boosted the protein assembly of PI3K-III complex I and II under OGD. Moreover, the colocalization of Vps34 with autophagosome marker LC3 or lysosome marker Lamp1 was augmented after Ubc9 overexpression, indicating a positive effect of Ubc9-boosted protein assembly of the PI3K-III complexes on autophagic flux enhancement.

Conclusions

We uncovered a novel role of Ubc9 in protecting cardiomyocytes from ischemic stress via Ubc9-induced SUMOylation, leading to increased PI3K-III complex assembly and autophagy-positioning. These findings may indicate a potential therapeutic target, Ubc9, for treatment of myocardial ischemia.

Zonisamide Ameliorates Cognitive Impairment by Inhibiting ER Stress in a Mouse Model of Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) increases the risk of Alzheimer’s disease (AD)-like dementia and pathology. Endoplasmic reticulum stress (ERS) plays a key role in the development of cognitive impairment in T2DM. Zonisamide (ZNS) was found to suppress ERS-induced neuronal cell damage in the experimental models of Parkinson’s disease (PD). However, the protective effect of Zonisamide in the treatment of diabetes-related dementia is not determined. Here, we studied whether ZNS can attenuate cognitive impairments in T2DM mice. C57BL/6J mice were fed with a high-fat diet (HFD) and received one intraperitoneal injection of streptozotocin (STZ) to develop T2DM. After the 9-week diet, the mice were orally gavaged with ZNS or vehicle for 16 consecutive weeks. We found that ZNS improved spatial learning and memory ability and slightly attenuated hyperglycemia. In addition, the expression levels of synaptic-related proteins, such as postsynaptic density 95 (PSD95) and synaptophysin, were increased along with the activation of the cyclic AMP response element-binding (CREB) protein and cAMP-dependent protein kinase (PKA) both in the hippocampus and cortex of T2DM mice. Meanwhile, ZNS attenuated Aβ deposition, Tau hyperphosphorylation at Ser-396/404, and also decreased the activity of Tau upstream kinases including extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK). Moreover, ZNS also decreased the ERS hallmark protein levels. These data suggest that ZNS can efficiently prevent cognitive impairment and improve AD-like pathologies by attenuating ERS in T2DM mice.

Ultrafast Electron Correlations and Memory Effects at Work: Femtosecond Demagnetization in Ni

Experimental observations of the ultrafast (less than 50 fs) demagnetization of Ni have so far defied theoretical explanations particularly since its spin-flipping time is much less than that resulting from spin-orbit and electron-lattice interactions. Through the application of an approach that benefits from spin-flip time-dependent density-functional theory and dynamical mean-field theory, we show that proper inclusion of electron correlations and memory (time dependence of electron-electron interaction) effects leads to demagnetization at the femtosecond scale, in good agreement with experimental observations. Furthermore, our calculations reveal that this ultrafast demagnetization results mainly from spin-flip transitions from occupied to unoccupied orbitals implying a dynamical reduction of exchange splitting. These conclusions are found to be valid for a wide range of laser pulse amplitudes. They also pave the way for ab initio investigations of ultrafast charge and spin dynamics in a variety of quantum materials in which electron correlations may play a definitive role.

[Investigation and analysis on characteristics of a cluster of COVID-19 associated with exposure in a department store in Tianjin]

Objective: To describe the epidemiological characteristics of a cluster of COVID-19 cases reported in Baodi district of Tianjin as of 18 February, 2020, which might be associated with the exposure in a local department store, and provide suggestions for prevention and control strategy development. Methods: The basic characteristics, time and area distributions, clinical manifestations, epidemiological history and transmission mode of the COVID-19 cases associated with the department store exposure were analyzed. Results: A total of 40 COVID-19 cases were associated with the department store exposure, accounting for 75.47% of the total confirmed cases (53 cases) reported in Baodi district. The cases were mainly at the age of 60 years or older (35.00%) and farmers (40.00%). The main clinical manifestations included fever (95.00%), cough (35.00%), and diarrhea (15.00%). The proportion of confirmed severe cases was 32.50%. The incidence curve showed that the incidence peak occurred on 31 January, 2020. Among the 40 cases, 6(15.00%) were department store employees, 19 (47.50%) were customers and 15 (37.50%) were close contacts (secondary cases). The first case occurred on 21 January, 2020, this case was a department store employee who had a purchasing history at whole sale markets in other provinces and cities before the onset, and 3 employees were still on duty after symptom onsets. The median of the incubation period of customer cases was 6 days, and the median of the interval between onset and medical treatment of customer cases was 7 days. Conclusion: This was a cluster epidemic of COVID-19, which might be associated with the exposure in the department store. By now, the current prevention and control measures have achieved satisfied effects.

Modulating the electronic and optical properties for SrTiO3/LaAlO3 bilayers treated as the 2D materials by biaxial strains

The emerging two-dimensional (2D) materials such as graphene have opened the door to industrial applications. Here, we consider the oxide perovskite monolayer of SrTiO₃ (STO), LaAlO₃ (LAO) and their heterostructures as the 2D transitional metal system. Results show that a band-gap transition from indirect to direct occurs when the separated monolayer STO (indirect band gap of 3.210 eV), and LAO (indirect band gap of 4.024 eV), form the heterostructures (direct band gap of 2.976 eV). The obtained bandgap for the stable bilayers may effectively be modulated by biaxial strains from  -12% to 8%. With 12% compressive biaxial strain, the band gap reduces to be 0.23 eV. The optical properties for the stable bilayers are also tuned by the biaxial strain. When the strain increases from compressive strain to tensile strain, the strongest peak of the imaginary part of dielectric function red shifts to lower energy. In comparing with the monolayer STO and LAO, the elastic property enhances obviously for the stable heterostructure, suggesting the heterostructure can be more stable freestanding or may be applied in device fabrications.

Development of a blocking immunoperoxidase monolayer assay for differentiation between pseudorabies virus-infected and vaccinated animalss

Pseudorabies (PR) outbreaks have devastated many swine farms in several parts of China since late 2011. The outbreak-associated pseudorabies virus (PRV) variant strains exhibited some typical amino acid changes in glycoprotein E (gE), a diagnostic antigen used for discriminating between PRV-infected and vaccinated animals (DIVA). To counteract the potential impact of epitope variations on current serological diagnostics of PRV, we produced monoclonal antibodies (mAbs) against gE protein of one representative PRV variant strain and developed a blocking immunoperoxidase monolayer assay (b-IPMA) for DIVA. The b-IPMA was based on the inhibition of binding between PRV-infected cells and mAb by PRV-specific antibodies present in clinical swine sera and was validated by comparison with a commercial PRV gpI Antibody Test Kit (IDEXX Laboratories, USA). The diagnostic sensitivity, diagnostic specificity and agreement were determined to be 99.25%, 98.18% and 99.02% respectively upon testing 509 serum samples. b-IPMA detected only PRV-specific antibodies and showed no cross- -reactivity with antibodies elicited by gE-deleted vaccine or other common swine pathogens. Thus, b-IPMA has the potential to be used for high-throughput screening of PRV-infected animals in veterinary clinics.

Impaired Vps34 complex activity-mediated autophagy inhibition contributes to endothelial progenitor cells damage in the ischemic conditions

AIMS

Endothelial progenitor cells (EPCs) are widely accepted to be applied in ischemic diseases. However, the therapeutic potency is largely impeded because of its inviability in these ischemic conditions. Autophagy is recognized to be vital in cell activity. Therefore, we explore the role and the mechanism of autophagy in ischemic EPCs.

METHODS AND RESULTS

We applied 7d-cultured bone marrow EPCs to investigate the autophagy status under the oxygen and glucose deprivation (OGD) conditions in vitro, mimicking the in-vivo harsh ischemia and anoxia microenvironment. We found increased EPC apoptosis, accompanied by an impaired autophagy activation. Intriguingly, mTOR inhibitor Rapamycin was incapable to reverse this damped autophagy and EPC damage. We further found that autophagy pathway downstream Vps34-Beclin1-Atg14 complex assembly and activity were impaired in OGD conditions, and an autophagy-inducing peptide Tat-Beclin1 largely recovered the impaired complex activity and attenuated OGD-stimulated EPC injury through restoring autophagy activation.

CONCLUSIONS

The present study discovered that autophagy activation is inhibited when EPCs located in the ischemia and anoxia conditions. Restoration of Vps34 complex activity obtains sufficient autophagy, thus promoting EPC survival, which will provide a potential target and advance our understanding of autophagy manipulation in stem cell transplantation.

Facile synthesis of novel dithioacetal-naphthalene derivatives as potential activators for plant resistance induction

In this paper, a series of novel dithioacetal–naphthalenes were designed and synthesized for plant immunity. Their antiviral activities were evaluated against tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV). The results indicated that most compounds exhibited better activity against CMV than against TMV. These dithioacetal derivatives also displayed good bacterial activity against rice bacterial leaf blight. Among them, compound S16 exhibited relatively good anti-CMV, anti-TMV, and antibacterial activity. Structure–activity relationships indicated that introducing the naphthalene moiety enhanced their activities for plant resistance induction. Therefore, the basic motif of compound S16 could be the most promising candidate for further structural optimization to develop a potential activator for plant resistance induction.

In this paper, a series of novel dithioacetal–naphthalenes were designed and synthesized for plant immunity.

Association of retinol binding protein-4, cystatin C, homocysteine and high-sensitivity C-reactive protein levels in patients with newly diagnosed type 2 diabetes mellitus

INTRODUCTION

To investigate the serum retinol binding protein (RBP)-4, cystatin C (Cys C), homocysteine (HCY) and high-sensitivity C-reactive protein (hs-CRP) levels in newly diagnosed type 2 diabetes mellitus (NT2DM) patients, prediabetes mellitus (PDM) subjects and normal controls, as well as their correlation with clinical and laboratory indexes, such as blood pressure and lipoprotein.

MATERIAL AND METHODS

A total of 242 subjects, including 141 NT2DM patients, 48 PDM subjects and 53 healthy controls, were recruited in the present study. Serum RBP-4, Cys C and hs-CRP concentrations were measured by enzyme-linked immunosorbent assay (ELISA). HCY concentration was determined by the chemical luminescence method.

RESULTS

There were significant differences in Cys C and hs-CRP among NT2DM patients, PDM subjects and normal controls. In comparison to controls, there were significantly elevated Cys C and hs-CRP levels in PDM (both p < 0.001), and a significantly increased Cys C level in NT2DM (p < 0.001); however, there were no significant differences in Cys C and hs-CRP levels between NT2DM and PDM, and no significant differences of hs-CRP levels between NT2DM and normal controls. No significant differences of RBP-4 and HCY levels among NT2DM, PDM and normal control groups were observed.

CONCLUSIONS

Aberrant Cys C expression and its clinical associations in NT2DM suggest their important role in this disease.

All-optical spin switching under different spin configurations

All-optical spin switching represents a new frontier in femtomagnetism. However, its underlying principles are quite different from traditional thermal activated spin switching. Here, we employ an atomic spin model and present a systematic investigation from a single spin to a large system of over a million spins. We find that for a single spin without an external perturbation, the conservation of total angular momentum requires that the spin change, if any, exactly matches the orbital momentum change, but a laser pulse significantly alters this relation, where the spin change does not necessarily follow the orbital change. This is reflected in the strong dependence of switching on laser polarization. To have an efficient spin switching, the electron initial momentum direction must closely follow the spin's orientation, so the orbital angular momentum is transverse to the spin and consequently the spin-orbit torque lies in the same direction as the spin. The module of the spin-orbit torque is [Formula: see text], where [Formula: see text] is the angle between spin [Formula: see text] and position [Formula: see text] (momentum [Formula: see text]) and [Formula: see text] is the angle between [Formula: see text] and [Formula: see text]. These findings are manifested in a much larger system. We find that the spin response depends on underlying spin structures. A linearly polarized laser pulse creates a dip in a uniform inplane-magnetized thin film, but has little effects on Néel and Bloch walls. Both right- and left- circularly polarized light ([Formula: see text] and [Formula: see text]) have stronger but different effects in both uniform spin domains and Néel walls. While [Formula: see text] light creates a basin of spins pointing down, [Formula: see text] light creates a mound of spins pointing up. In the vicinity of the structure spins are reversed, similar to the experimental observation. [Formula: see text] light has a dramatic effect, disrupting spins in Bloch walls. By contrast, [Formula: see text] light has a small effect on Bloch walls because [Formula: see text] only switches down spins up and once the spins already point up, there is no major effect. These findings are expected to have important implications in the future.

Endophilin A2 attenuates cardiac hypertrophy induced by isoproterenol through the activation of autophagy

Decreased autophagy has been reported to contribute to the progression of cardiac hypertrophy. Our previous research has demonstrated that endophilin A2 (EndoA2) attenuates H₂O₂-induced cardiomyocyte apoptosis by strengthening autophagy. However, the role of EndoA2 in the regulation of autophagy in cardiac hypertrophy is unknown. In this study, we tested the hypothesis that EndoA2 suppresses cardiac hypertrophy induced by isoproterenol (ISO) by activating autophagy. In vivo, we established a cardiac hypertrophy model by subcutaneous injection of ISO and used intramyocardial delivery of adenovirus vector harboring EndoA2 cDNA (Ad-EndoA2) to overexpress EndoA2. The cardiac hypertrophic response and autophagy level were measured. EndoA2 overexpression suppressed pathological cardiac hypertrophy and enhanced autophagy in rat hearts. In addition, the effects of EndoA2 on cardiac hypertrophy and autophagy were observed in cultured neonatal rat cardiomyocytes (NRCMs) with gain- and loss-of-function approaches to regulate EndoA2 expression. The results were consistent with those of the in vivo study. Furthermore, the involvement of EndoA2-mediated autophagy in the attenuation of ISO-induced cardiac hypertrophy was explored by pharmaceutical inhibition of autophagy. Pretreatment with 3-methyladenine (3-MA) clearly diminished the anti-hypertrophic effects of EndoA2 in ISO-treated NRCMs. The results presented here provide the first evidence that EndoA2 is involved in ISO-induced cardiac hypertrophy. The anti-hypertrophic effects of EndoA2 can be partially attributed to its regulation of autophagy.

[Optimization of delivering minimum Gd-DTPA at the posterior upper point on tympanic medial wall and hT2W-3D-FLAIR sequence for detecting endolymphatic hydrops]

Objective: To optimize delivery of gadolinium-diethylenetriamine pentaacetic acid(Gd-DTPA) at the posterior upper point on tympanic medial wall and heavily T2-weighted 3-dimensional fluid-attenuated inversion recovery (hT2W-3D-FLAIR) sequence, and to implement the technique of detecting endolymphatic hydrops using gadolinium-enhancement MRI. Methods: Thirteen patients with periphery vertigo, who visited Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Changhai Hospital during June and December of 2017, were enrolled in the study.0.10-0.20 ml of Gd-DTPA in various dilutions (10, 20, and 40-fold) were delivered at the posterior upper point on tympanic medial wall using a soft-tipped tympanic suction and drug-spraying needle through an artificially perforated tympanic membrane. Inner ear MRI was performed at 8, 24 h after Gd-DTPA administration using a 3T MR machine in combination with a 20-channel Tim 4G head/neck coil and the sequence of hT2W-3D-FLAIR to detect the gadolinium-enhancement signal within the inner ear and possible endolymphatic hydrops. The scanning time was either 8 min 35 s or 15 min 11 s. Results: Efficient inner ear uptake of Gd-DTPA was detected and induced high signal to noise ratio of MRI in patients receiving targeted delivery of 0.15-0.20 ml of 10-fold diluted contrast agent at the posterior upper point on tympanic medial wall. At 8 h after delivery, significant uptake was detected in the scala tympani and vestibuli of hook region and basal turn of the cochlea, and perilymhatic compartment of the vestibule. At 24 h after delivery, the distribution of Gd-DTPA became homogenous in each turn of the cochlea and perilymphatic compartment of the vestibule. However, obvious individual variance existed in the inner ear uptake when 0.10 ml of 40-fold diluted Gd-DTPA was delivered. Efficient inner ear uptake and high quality images that generated in patients receiving 0.10, 0.15, and 0.20 ml of 20-fold Gd-DTPA demonstrated endolymphatic hydrops with minor individual variance. There was insignificant difference in the enhancement signal of inner ear between 0.15 and 0.10 ml groups when Gd-DTPA was diluted at 20-fold except for the signal of semicircular canal of 0.15 ml group (190.00±53.95 vs 165.50±42.13, t=2.61, P<0.05). There was insignificant difference in the image quality between 8 min 35 s and 15 min 11 s canning time. Various degrees of endolymphatic hydrops were detected in 7 cochleae and 11 vestibule, and both simultaneous cochlear and vestibular endolymphatic hydrops were detected in 4 ears. Cochlear endolymphatic hydrops was detected in all the 3 patients with definite Meniere's disease, and 2 of them had combined cochlear and vestibular endolymphatic hydrops. Endolymphatic hydrops was not detected in patients with possible Meniere's disease nor with symptoms of superior semicircular canal dehiscence. Conclusion: Targeted delivery of 0.10 ml with 20-fold diluted Gd-DTPA (total dosage of 5 μmol) at the posterior upper point on tympanic medial wall in combination with 8 min 35 s scanning time hT2W-3D-FLAIR sequence for inner ear MRI in a 3T MR machine is a clinically practical method to detect endolymphatic hydrops, and reduce the requirement for MRI hardware.

Laser-induced ultrafast transport and demagnetization at the earliest time: first-principles and real-time investigation

It is generally believed that there are at least two ways to use an ultrafast laser pulse to demagnetize a magnetic sample. One is to directly photo-demagnetize the system through spin-orbit coupling (SOC), and the other is to utilize ultrafast hot electron transport without SOC. The challenge is that these two processes are entangled on the same time scale. While the experimental results have been inconclusive, theoretical investigations are even scarcer, beyond those earlier studies based on spin superdiffusion. For instance, we do not even know how fast electrons move under laser excitation and how far they move. Here we carry out a first-principles time-dependent calculation to investigate how fast electrons actually move under laser excitation and how large the electron transport affects demagnetization on the shortest time scale. To take into account the transport effect, we implement the intraband transition in our theory. In the bulk fcc Ni, we find the effect of the spin transport on the demagnetization is extremely small, no more than 1%. The collective electron velocity in Ni is 0.4 Å fs^-1, much smaller than the Fermi velocity, and the collective displacement is no more than 0.1 Å. But this does not mean that electrons do not travel fast; instead we find that electron velocities at two opposite crystal momenta cancel each other. We follow the Γ-X line and find a huge dispersion in the velocities in the crystal momentum space. In the Fe/W(1 1 0) thin film, the overall demagnetization is larger than Ni, and the Fermi velocity is higher than Ni. However, the effect of the spin transport is still small in the Fe/W(1 1 0) thin film. Based on our numerical results and existing experimental findings, we propose a different mechanism that can explain two latest experimental results. Our finding sheds new light on the effect of ballistic transport on demagnetization.

Generating high-order optical and spin harmonics from ferromagnetic monolayers

High-order harmonic generation (HHG) in solids has entered a new phase of intensive research, with envisioned band-structure mapping on an ultrashort time scale. This partly benefits from a flurry of new HHG materials discovered, but so far has missed an important group. HHG in magnetic materials should have profound impact on future magnetic storage technology advances. Here we introduce and demonstrate HHG in ferromagnetic monolayers. We find that HHG carries spin information and sensitively depends on the relativistic spin-orbit coupling; and if they are dispersed into the crystal momentum k space, harmonics originating from real transitions can be k-resolved and carry the band structure information. Geometrically, the HHG signal is sensitive to spatial orientations of monolayers. Different from the optical counterpart, the spin HHG, though probably weak, only appears at even orders, a consequence of SU(2) symmetry. Our findings open an unexplored frontier-magneto-high-order harmonic generation.

Manifestation of intra-atomic 5d6s-4f exchange coupling in photoexcited gadolinium

Intra-atomic exchange couplings (IECs) between 5d6s and 4f electrons are ubiquitous in rare-earth metals and play a critical role in spin dynamics. However, detecting them in real time domain has been difficult. Here we show the direct evidence of IEC between 5d6s and 4f electrons in gadolinium. Upon femtosecond laser excitation, 5d6s electrons are directly excited; their majority bands shift toward the Fermi level while their minority bands do the opposite. For the first time, our first-principles minority shift now agrees with the experiment quantitatively. Excited 5d6s electrons lower the exchange potential barrier for 4f electrons, so the 4f states are also shifted in energy, a prediction that can be tested experimentally. Although a significant number of 5d6s electrons, some several eV below the Fermi level, are excited out of the Fermi sea, there is no change in the 4f states, a clear manifestation of intra-atomic exchange coupling.

Is perpendicular magnetic anisotropy essential to all-optical ultrafast spin reversal in ferromagnets?

All-optical spin reversal presents a new opportunity for spin manipulations, free of a magnetic field. Most of all-optical-spin-reversal ferromagnets are found to have a perpendicular magnetic anisotropy (PMA), but it has been unknown whether PMA is necessary for spin reversal. Here we theoretically investigate magnetic thin films with either PMA or in-plane magnetic anisotropy (IMA). Our results show that spin reversal in IMA systems is possible, but only with a longer laser pulse and within a narrow laser parameter region. Spin reversal does not show a strong helicity dependence where the left- and right-circularly polarized light lead to the identical results. By contrast, the spin reversal in PMA systems is robust, provided both the spin angular momentum and laser field are strong enough while the magnetic anisotropy itself is not too strong. This explains why experimentally the majority of all-optical spin-reversal samples are found to have strong PMA and why spins in Fe nanoparticles only cant out of plane. It is the laser-induced spin-orbit torque that plays a key role in the spin reversal. Surprisingly, the same spin-orbit torque results in laser-induced spin rectification in spin-mixed configuration, a prediction that can be tested experimentally. Our results clearly point out that PMA is essential to spin reversal, though there is an opportunity for in-plane spin reversal.

Mechanical properties of crossed-lamellar structures in biological shells: A review

The self-fabrication of materials in nature offers an alternate and powerful solution towards the grand challenge of designing advanced structural materials, where strength and toughness are always mutually exclusive. Crossed-lamellar structures are the most common microstructures in mollusks that are composed of aragonites and a small amount of organic materials. Such a distinctive composite structure has a fracture toughness being much higher than that of pure carbonate mineral. These structures exhibiting complex hierarchical microarchitectures that span several sub-level lamellae from microscale down to nanoscale, can be grouped into two types, i.e., platelet-like and fiber-like crossed-lamellar structures based on the shapes of basic building blocks. It has been demonstrated that these structures have a great potential to strengthen themselves during deformation. The observed underlying toughening mechanisms include microcracking, channel cracking, interlocking, uncracked-ligament bridging, aragonite fiber bridging, crack deflection and zig-zag, etc., which play vital roles in enhancing the fracture resistance of shells with the crossed-lamellar structures. The exploration and utilization of these important toughening mechanisms have attracted keen interests of materials scientists since they pave the way for the development of bio-inspired advanced composite materials for load-bearing structural applications. This article is aimed to review the characteristics of hierarchical structures and the mechanical properties of two kinds of crossed-lamellar structures, and further summarize the latest advances and biomimetic applications based on the unique crossed-lamellar structures.

Quantum mechanical interpretation of the ultrafast all optical spin switching

The all-optical spin switching induced by an intense (∼TW cm^-2), near-infrared (775 nm), ultrashort (∼100 fs) circularly-polarized laser pulse is studied based on the spin-orbit coupled Heisenberg model. We find that the magnetic spin momentum undergoes an oscillation in time during the interaction with a driving laser pulse, which can be explained as a classical counterpart of the Rabi oscillation associated with a spin-orbit coupling. The optimal spin reversal is achieved by adjusting the pulse duration to one half the Rabi oscillation period. A successive spin reversal by a delayed pulse is possible if it has the opposite helicity and a shorter duration relative to the first pulse. Moreover, inclusion of an exchange interaction term in the Hamiltonian leads to a precession of the magnetic spin momentum that lasts even after the driving laser pulse turns off. This spin precession is stronger in antiferromagnets than ferrimagnets.

Chloroquine improves left ventricle diastolic function in streptozotocin-induced diabetic mice

Diabetes is a potent risk factor for heart failure with preserved ejection fraction (HFpEF). Autophagy can be activated under pathological conditions, including diabetic cardiomyopathy. The therapeutic effects of chloroquine (CQ), an autophagy inhibitor, on left ventricle function in streptozotocin (STZ)-induced diabetic mice were investigated. The cardiac function, light chain 3 (LC3)-II/LC3-I ratio, p62, beclin 1, reactive oxygen species, apoptosis, and fibrosis were measured 14 days after CQ (ip 60 mg/kg/d) administration. In STZ-induced mice, cardiac diastolic function was decreased significantly with normal ejection fraction. CQ significantly ameliorated cardiac diastolic function in diabetic mice with HFpEF. In addition, CQ decreased the autophagolysosomes, cardiomyocyte apoptosis, and cardiac fibrosis but increased LC3-II and p62 expressions. These results suggested that CQ improved the cardiac diastolic function by inhibiting autophagy in STZ-induced HFpEF mice. Autophagic inhibitor CQ might be a potential therapeutic agent for HFpEF.

Deciphering the Draft Genome of Toxoplasma gondii RH Strain

Toxoplasmosis is a widespread parasitic infection by Toxoplasma gondii, a parasite with at least three distinct clonal lineages. This article reports the whole genome sequencing and de novo assembly of T. gondii RH (type I representative strain), as well as genome-wide comparison across major T. gondii lineages. Genomic DNA was extracted from tachyzoites of T. gondii RH strain and its identity was verified by PCR and LAMP. Subsequently, whole genome sequencing was performed, followed by sequence filtering, genome assembly, gene annotation assignments, clustering of gene orthologs and phylogenetic tree construction. Genome comparison was done with the already archived genomes of T. gondii. From this study, the genome size of T. gondii RH strain was found to be 69.35Mb, with a mean GC content of 52%. The genome shares high similarity to the archived genomes of T. gondii GT1, ME49 and VEG strains. Nevertheless, 111 genes were found to be unique to T. gondii RH strain. Importantly, unique genes annotated to functions that are potentially critical for T. gondii virulence were found, which may explain the unique phenotypes of this particular strain. This report complements the genomic archive of T. gondii. Data obtained from this study contribute to better understanding of T. gondii and serve as a reference for future studies on this parasite.

Ultrafast reduction of exchange splitting in ferromagnetic nickel

A decade ago Rhie et al (2003 Phys. Rev. Lett. 90 247201) reported that when ferromagnetic nickel is subject to an intense ultrashort laser pulse, its exchange splitting is reduced quickly. But to simulate such reduction remains a big challenge. The popular rigid band approximation (RBA), where both the band structure and the exchange splitting are held fixed before and after laser excitation, is unsuitable for this purpose, while the time-dependent density functional theory could be time-consuming. To overcome these difficulties, we propose a time-dependent Liouville and density functional theory (TDLDFT) that integrates the time-dependent Liouville equation into the density functional theory. As a result, the excited charge density is reiterated back into the Kohn-Sham equation, and the band structure is allowed to change dynamically. Even with the ground-state density functional, a larger demagnetization than RBA is found; after we expand Ortenzi's spin scaling method into an excited-state (laser) density functional, we find that the exchange splitting is indeed strongly reduced, as seen in the experiment. Both the majority and minority bands are shifted toward the Fermi level, but the majority shifts a lot more. The ultrafast reduction in exchange splitting occurs concomitantly with demagnetization. While our current theory is still unable to yield the same percentage loss in the spin moment as observed in the experiment, it predicts a correct trend that agrees with the experiments. With a better functional, we believe that our results can be further improved.

Sonic hedgehog improves ischemia-induced neovascularization by enhancing endothelial progenitor cell function in type 1 diabetes

The Sonic hedgehog (Shh) pathway is downregulated in type 1 diabetes, and it has been reported that augmentation of this pathway may alleviate diabetic complications. However, the cellular mechanisms underlying these protective effects are poorly understood. Recent studies indicate that impaired function of endothelial progenitor cells (EPCs) may contribute to cardiovascular problems in diabetes. We hypothesized that impaired Shh signaling contribute to endothelial progenitor cell dysfunction and that activating the Shh signaling pathway may rescue EPC function and promote diabetic neovascularization. Adult male C57/B6 mice and streptozotocin (STZ)-induced type 1 diabetic mice were used. Gli1 and Ptc1 protein levels were reduced in EPCs from diabetic mice, indicating inhibition of the Shh signaling pathway. EPC migration, tube formation ability, and mobilization were impaired in diabetic mice compared with non-diabetic controls (p < 0.05 vs control), and all were improved by in vivo administration of the Shh pathway receptor agonist SAG (p < 0.05 vs diabetes). SAG significantly increased capillary density and blood perfusion in the ischemic hindlimbs of diabetic mice (p < 0.05 vs diabetes). The AKT activity was lower in EPCs from diabetic mice than those from non-diabetic controls (p < 0.05 vs control). This decreased AKT activity led to an increased GSK-3β activity and degradation of the Shh pathway transcription factor Gli1/Gli2. SAG significantly increased the activity of AKT in EPCs. Our data clearly demonstrate that an impaired Shh pathway mediated by the AKT/GSK-3β pathway can contribute to EPC dysfunction in diabetes and thus activating the Shh signaling pathway can restore both the number and function of EPCs and increase neovascularization in type 1 diabetic mice.

Oxidative stress contributes to the impaired sonic hedgehog pathway in type 1 diabetic mice with myocardial infarction

Our previous study demonstrated that an impaired sonic hedgehog (Shh) pathway contributed to cardiac dysfunction in type 1 diabetic mice with myocardial infarction (MI). The present study aimed to test the hypothesis that oxidative stress may contribute to the impaired Shh pathway and cardiac dysfunction in type 1 diabetic mice with MI. Streptozotocin-induced type 1 diabetic mice (C57/Bl6, male) and rat neonatal cardiomyocytes were used in the present study. Mice were randomly assigned to undergo ligation of the coronary artery or pseudosurgery. A potent antioxidant Tempol was administered in vivo and in vitro. Cardiac function was assessed by echocardiography, capillary density by immunohistochemisty, percentage of myocardial infarct using Massons trichrome staining, reactive oxygen species detection using dihydroethidium dye or 2,7-dichlorofluorescein diacetate probe and protein expression levels of the Shh pathway by western blot analysis. The antioxidant Tempol was shown to significantly increase myocardial protein expression levels of Shh and patched-1 (Ptc1) at 7–18 weeks and improved cardiac function at 18 weeks in type 1 diabetic mice, as compared with mice receiving no drug treatment. Furthermore, myocardial protein expression levels of Shh and Ptc1 were significantly upregulated on day 7 after MI, and capillary density was enhanced. In addition, the percentage area of myocardial infarct was reduced, and the cardiac dysfunction and survival rate were improved on day 21 in diabetic mice treated with Tempol. In vitro, treatment of rat neonatal cardiomyocytes with a mixture of xanthine oxidase and xanthine decreased protein expression levels of Shh and Ptc1 in a concentration-dependent manner, and Tempol attenuated this effect. These results indicate that oxidative stress may contribute to an impaired Shh pathway in type 1 diabetic mice, leading to diminished myocardial healing and cardiac dysfunction. Antioxidative strategies aimed at restoring the endogenous Shh pathway may offer a useful means for improving diabetic cardiac function.

Draft genome of Brugia pahangi: high similarity between B. pahangi and B. malayi

BACKGROUND

Efforts to completely eradicate lymphatic filariasis from human population may be challenged by the emergence of Brugia pahangi as another zoonotic lymphatic filarial nematode. In this report, a genomic study was conducted to understand this species at molecular level.

METHODS

After blood meal on a B. pahangi-harbouring cat, the Aedes togoi mosquitoes were maintained to harvest infective third stage larvae, which were then injected into male Mongolian gerbils. Subsequently, adult B. pahangi were obtained from the infected gerbil for genomic DNA extraction. Sequencing and subsequently, construction of genomic libraries were performed. This was followed by genomic analyses and gene annotation analysis. By using archived protein sequences of B. malayi and a few other nematodes, clustering of gene orthologs and phylogenetics were conducted.

RESULTS

A total of 9687 coding genes were predicted. The genome of B. pahangi shared high similarity to that B. malayi genome, particularly genes annotated to fundamental processes. Nevertheless, 166 genes were considered to be unique to B. pahangi, which may be responsible for the distinct properties of B. pahangi as compared to other filarial nematodes. In addition, 803 genes were deduced to be derived from Wolbachia, an endosymbiont bacterium, with 44 of these genes intercalate into the nematode genome.

CONCLUSIONS

The reporting of B. pahangi draft genome contributes to genomic archive. Albeit with high similarity to B. malayi genome, the B. pahangi-unique genes found in this study may serve as new focus to study differences in virulence, vector selection and host adaptability among different Brugia spp.

Magnetic spin moment reduction in photoexcited ferromagnets through exchange interaction quenching: beyond the rigid band approximation

The exchange interaction among electrons is one of the most fundamental quantum mechanical interactions in nature and underlies any magnetic phenomena from ferromagnetic ordering to magnetic storage. The current technology is built upon a thermal or magnetic field, but a frontier is emerging to directly control magnetism using ultrashort laser pulses. However, little is known about the fate of the exchange interaction. Here we report unambiguously that photoexcitation is capable of quenching the exchange interaction in all three 3d ferromagnetic metals. The entire process starts with a small number of photoexcited electrons which build up a new and self-destructive potential that collapses the system into a new state with a reduced exchange splitting. The spin moment reduction follows a Bloch-like law as M(z)(ΔE) = M(z)(0)(1 - ΔE/ΔE₀)(1/β), where ΔE is the absorbed photon energy and β is a scaling exponent. A good agreement is found between the experimental and our theoretical results. Our findings may have a broader implication for dynamic electron correlation effects in laser-excited iron-based superconductors, iron borate, rare-earth orthoferrites, hematites and rare-earth transition metal alloys.

Ultrafast reduction in exchange interaction by a laser pulse: alternative path to femtomagnetism

Since the beginning of femtomagnetism, it has been hotly debated how an ultrafast laser pulse can demagnetize a sample and switch its spins within a few hundred femtoseconds, but no consensus has been reached. In this paper, we propose that an ultrafast reduction in the exchange interaction by a femtosecond laser pulse is mainly responsible for demagnetization and spin switching. The key physics is that the dipole selection rule demands two distinctive electron configurations for the ground and excited states and consequently changes the exchange interaction. Although the exchange interaction change is almost instantaneous, its effect on the spin is delayed by the finite spin wave propagation. Consistent with the experimental observation, the delay becomes longer with a stronger exchange interaction pulse. In spin-frustrated systems, the effect of the exchange interaction change is even more dramatic, where the spin can be directly switched from one direction to the other. Therefore, our theory has the potential to explain the essence of major observations in rare-earth transition metal compounds for the last seven years. Our findings are likely to motivate further research in the quest of the origin of femtomagnetism.

Thermal or nonthermal? That is the question for ultrafast spin switching in GdFeCo

GdFeCo is among the most interesting magnets for producing laser-induced femtosecond magnetism, where light can switch its spin moment from one direction to another. This paper aims to set a criterion for the thermal/nonthermal mechanism: we propose to use the Fermi-Dirac distribution function as a reliable criterion. A precise value for the thermalization time is needed, and through a two-level model, we show that since there is no direct connection between the laser helicity and the definition of thermal/nonthermal processes, the helicity is a poor criterion for differentiating a thermal from a nonthermal process. In addition, we propose a four-site model system (Gd2Fe2) for investigating the transient ferromagnetic ordering between Gd and Fe ions. We find that states of two different kinds can allow such an ordering. One state is a pure ferromagnetic state with ferromagnetic ordering among all the ions, and the other is the short-ranged ferromagnetic ordering of a pair of Gd and Fe ions.

Shear stress-driven refreshing capability of plastic deformation in nanolayered metals

Severely localized deformation within shear bands can occur much more easily in a metal with nanoscale microstructures, such as nanograined and nanolayered materials. Based on atomic-scale observations, here we show that such locally large deformation (the continuous thinning of the layers) within the indentation-induced shear bands of the Cu/Au nanolayers is essentially attributed to the large shear stress component along the interface, which can refresh the capability of the interface to absorb incoming dislocations through unlocking the product of the dislocation-interface reaction. The results have implications for understanding the interface-mediated mechanisms of plastic deformation and for the engineering application of severe plastic deformation processing of metals at nanoscales.

Electronic and spin transport properties of graphene nanoribbon mediated by metal adatoms: a study by the QUAMBO-NEGF approach

Structural and electronic properties, including deformation, magnetic moment, Mulliken population, bond order, as well as electronic transport properties, of zigzag graphene nanoribbon (ZGNR) with Co adatoms on hollow sites are investigated by quasi-atomic minimal basis orbits (QUAMBOs), a first-principles tight binding (TB) scheme based on density functional theory (DFT), combined with a non-equilibrium Green's function. For electronic transport, below the Fermi level the transmission is strongly suppressed and spin dependent as a result of magnetism by Co adatom adsorption, while above the Fermi level the transmission is slightly distorted and spin independent. Due to the local environment dependence of QUAMBOs-TB parameters, we construct QUAMBOs-TB parameters of ZGNR leads and ZGNR with Co adatoms on hollow center sites by a divide-and-conquer approach, and accurately reproduce the electronic transmission behavior. Our QUAMBO-NEGF method is a new and promising way of examining electronic transport in large-scale systems.

[The role of TLR4-mediated MyD88-dependent pathway in neuroinflammation in hippocampal neurons of rats]

OBJECTIVE

To investigate weather there is a toll-like receptor 4 (TLR4)-mediated myeloid differentiation factor 88 (MyD88)-dependent pathway in hippocampal neurons of rats and the probable role of the pathway in neuroinflammation.

METHODS

To establish the proper model, primarily cultured hippocampal neurons were treated with lipopolysaccharides (LPS), or pretreated with TLR4 antibody then co-treated with LPS. The expression of mRNA of MyD88 and TNF-alpha receptor associated factor 6 (TRAF6) were tested by RT-qPCR. The content of MyD88 and TRAF6 were tested by Western blot. The nuclear translocation of nuclear factor-kappaB/P65 (NF-kappaB/p65) was tested by immunofluorescence. The content of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and nitric oxide (NO) were tested by ELISA.

RESULTS

LPS could increase MyD88 and TRAF6 mRNA, upregulate protein level of MyD88 and TRAF6 and increase the level of TNF-alpha, IL-1beta and NO in cell culture supernatant. LPS also could promote NF-kappa B/p65 translation to the nucleus. The pretreatment with TLR4 antibody reduced the translocation to nucleus for NF-kappaB/P65 and the contents of TNF-alpha, IL-1beta and NO in the culture supernatant.

CONCLUSION

There is a TLR4-mediated MyD88-dependent pathway in hippocampal neurons. The activation of this pathway can increase the level of TNF-alpha, IL-1beta and NO in cell culture supernatant. TLR4-mediated MyD88-dependent pathway in hippocampal neurons participate in neuroinflammation, that means neurons are not passive in inflammation.

Proposed coherent trapping of a population of electrons in a C60 molecule induced by laser excitation

This Letter demonstrates the possibility of generating coherent population trapping in C(60). Similar to a three-level Λ system, C(60) has a forbidden transition between the highest occupied molecular orbital (HOMO) (|a}) and the lowest unoccupied molecular orbital (LUMO) (|c}), but a dipole-allowed transition between HOMO and LUMO+1 (|b}) and between |b} and |c}. We employ two cw laser fields, one coupling and one probe. The strong coupling field is switched on first to resonantly excite the transition between |b} and |c}. After a delay, the probe is switched on; the coherent interaction between the coupling and probe fields traps the population in |a} and |c}. This forms a partially dark state in C(60), analogous to that in atomic vapors. Turning off the coupling field restores C(60)'s absorption. Pulsed lasers work as well. We use two pulses to steer the system into a dark state; when we send in a cw probe field, the electric polarization of C(60) plunges by five times, in comparison with the noncontrol case. This should be detectable experimentally.

Magnetic ordering and structural phase transitions in a strained ultrathin SrRuO3/SrTiO3 superlattice

Ruthenium-based perovskite systems are attractive because their structural, electronic, and magnetic properties can be systematically engineered. The SrRuO3/SrTiO3 superlattice, with its period consisting of one unit cell each, is very sensitive to strain change. Our first-principles simulations reveal that, in the high tensile strain region, it transits from a ferromagnetic metal to an antiferromagnetic insulator with clear tilted octahedra, while in the low strain region, it is a ferromagnetic metal without octahedra tilting. Detailed analyses of three spin-down Ru-t(2g) orbitals just below the Fermi level reveal that the splitting of these orbitals underlies these dramatic phase transitions, with the rotational force constant of RuO(6) octahedron high up to 16 meV/Deg(2), 4 times larger than that of TiO(6). Differently from nearly all the previous studies, these transitions can be probed optically through the diagonal and off-diagonal dielectric tensor elements. For a 1% change in strain, our experimental spin moment change is -0.14±0.06 μ(B), quantitatively consistent with our theoretical value of -0.1 μ(B).

An empirical investigation of bias and variance in time series forecasting: modeling considerations and error evaluation

Bias and variance play an important role in understanding the fundamental issue of learning and generalization in neural network modeling. Several studies on bias and variance effects have been published in classification and regression related research of neural networks. However, little research has been done in this area for time-series modeling and forecasting. We consider modeling issues related to understanding error components given the common practices associated with neural-network time-series forecasting. We point out the key difference between classification and time-series problems in consideration of the bias-plus-variance decomposition. A Monte Carlo study on the role of bias and variance in neural networks time-series forecasting is conducted. We find that both input lag structure and hidden nodes are important in contributing to the overall forecasting performance. The results also suggest that overspecification of input nodes in neural network modeling does not impact the model bias, but has significant effect on the model variance. Methods such as neural ensembles that focus on reducing the model variance, therefore, can be valuable and effective in time-series forecasting modeling.

Impaired sonic hedgehog pathway contributes to cardiac dysfunction in type 1 diabetic mice with myocardial infarction

AIMS

The incidence and mortality of myocardial infarction (MI) in diabetic patients are higher than in non-diabetic patients; however, the mechanisms by which diabetes results in cardiac dysfunction are poorly understood. The present study tested the hypothesis that an impaired sonic hedgehog (Shh) pathway contributes to cardiac dysfunction in type 1 diabetic mice with MI.

METHODS AND RESULTS

Adult male C57/B6 mice and streptozotocin-induced type 1 diabetic mice were used. Myocardial proteins of Shh, Patched-1 (Ptc1), and glioma-associated oncogene-1 (Gli1) were significantly decreased in type 1 diabetic mice at 10 weeks, and this was accompanied by cardiac dysfunction. Although myocardial proteins of Shh, Ptc1, and Gli1 were significantly increased 7 days after MI compared with the sham group in control mice, these proteins were markedly decreased in streptozotocin-induced diabetic mice. Treatment with Shh pathway agonist for 21 days significantly increased Ptc1 and Gli1 proteins, enhanced capillary density, reduced the percentage myocardial infarct, and then improved cardiac function in diabetic mice with MI compared with those with no drug treatment. This treatment had no effects in control mice with MI. Conversely, treatment with Shh pathway antagonist for 21 days significantly decreased Ptc1 and Gli1 proteins, reduced capillary density, enlarged the percentage myocardial infarct, and then exacerbated cardiac dysfunction in control mice with MI compared with those with no drug treatment.

CONCLUSIONS

These findings indicate that in type 1 diabetic mice the myocardial Shh pathway is impaired and that the impaired Shh pathway contributes to cardiac dysfunction. Strategies that are aimed at augmenting the Shh pathway may offer useful means for improving diabetic cardiac dysfunction.