Effects of simulated nitrogen deposition on soil respiration in a Bambusa pervariabilis x Dendrocala mopsi plantation in rainy area of West China

From January 2008 to February 2009, a field experiment was conducted in Rainy Area of West China to understand the effects of nitrogen (N) deposition on the soil respiration in a Bambusa pervariabilis x Dendrocala mopsi plantation. Four treatments were installed, i. e., no N added (control), 5 g N m(-2) a(-1) (low-N), 15 g N m(-2) a(-1) (medium-N), and 30 g N m(-2) a(-1) (high-N), and soil respiration rate was determined by infra-red CO2 analyzer. In the plantation, soil respiration rate had an obvious seasonal change, with the maximum in July and the minimum in January. In control plot, the annual cumulative soil respiration was (389 +/- 34) g m(-2) a(-1). Soil respiration rate had significant positive exponential relationships with soil temperature at 10 cm depth and air temperature, and significant positive linear relationships with soil microbial biomass carbon (MBC) and nitrogen (MBN). Simulated N deposition promoted soil respiration significantly, with significant differences between the low- and medium-N and the control but no significant difference between high-N and the control. In control plot, surface soil (0-20 cm) MBC and MBN were 0.460 and 0.020 mg g(-1), respectively. In N-added plots, both the MBC and the MBN had significant increase. The fine root density in surface soil was 388 g m(-2), which was less affected by simulated N deposition. The soil respiration Q10 value calculated from soil temperature at 10 cm depth and air temperature was 2.66 and 1.87, respectively, and short-term N deposition had lesser effects on the Q10 value. The variation of soil respiration in the plantation was mainly controlled by temperature and soil microbial biomass, and simulated N deposition could increase the CO2 emission via increasing soil microbial biomass.     

High-throughput microfluidic system for long-term bacterial colony monitoring and antibiotic testing in zero-flow environments

In this study, a high-throughput microfluidic system is presented. The system is comprised of seven parallel channels. Each channel contains 32 square-shaped microchambers. After simulation studies on samples loaded into the microchambers, and the solute exchange between the microchambers and channels, the long-term culture of Escherichia coli (E. coli) HB101 in the microchambers is realized. Using the principle that L-arabinose (L-Ara) can induce recombinant E. coli HB101 pGLO to synthesize green fluorescent protein (GFP), the real-time analysis of GFP expression in different initial bacterial densities is performed. The results demonstrate that higher initial loading densities of the bacterial colony cause bacterial cell to enter log-phase proliferation sooner. High or low initial loading densities of the bacterial cell suspension induce the same maximum growth rates during the log-phase. Quantitative on-chip analysis of tetracycline and erythromycin inhibition on bacterial cell growth is also conducted. Bacterial morphology changes during antibiotic treatment are observed. The results show that tetracycline and erythromycin exhibit different inhibition activities in E. coli cells. Concentrations of 3 μg/mL tetracycline can facilitate the formation of long filamentous bacteria with the average length of more than 50 μm. This study provides an on-chip framework for bacteriological research in a high-throughput manner and the development of recombinant bacteria-based biosensors for the detection of specific substances.     

Substrate-controlled chemoselective synthesis and potent cytotoxic activity of novel 5,6,7-triarylpyrido[2,3-d]pyrimidin-4-one derivatives

The substrate-controlled chemoselective synthesis of novel 5,6,7-triarylpyrido[2,3-d]pyrimidin-4-one derivatives has been successfully achieved via microwave-assisted three-component reactions of 2,6-diaminopyrimidin-4(3H)-one, aromatic aldehydes and 1,2-diphenylethanone. This approach has the prominent features of chemoselectivity, diasteroselectivity, atom economy, short reaction time, high yield as well as operational simplicity. Moreover, these novel compounds were subject to the test of in vitro cytotoxicity to carcinoma SW1116 and SGC7901 cells. Most of the tested compounds showed significant cytotoxicity to SW1116 cells and compound 4b exhibited more potent and efficacious cytotoxicity to SGC7901 cells than doxorubicin hydrochloride as positive control.     

Ligand‐Assisted Assembly Approach to Synthesize Large‐Pore Ordered Mesoporous Titania with Thermally Stable and Crystalline Framework

A novel ligand‐assisted assembly approach is demonstrated for the synthesis of thermally stable and large‐pore ordered mesoporous titanium dioxide with a highly crystalline framework by using diblock copolymer poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) as a template and titanium isopropoxide (TIPO) as a precursor. Small‐angle X‐ray scattering, X‐ray diffraction (XRD), transmission electron microscopy (TEM), high‐resolution scanning electron microscopy, and N₂‐sorption measurements indicate that the obtained TiO₂ materials possess an ordered primary cubic mesostructure with large, uniform pore diameters of about 16.0 nm, and high Brunauer–Emmett–Teller surface areas of ～112 m² g^?1, as well as high thermal stability (～700 °C). High resolution TEM and wide‐angle XRD measurements clearly illustrate the high crystallinity of the mesoporous titania with an anatase structure in the pore walls. It is worth mentioning that, in this process, in addition to tetrahydrofuran as a solvent, acetylacetone was employed as a coordination agent to avoid rapid hydrolysis of the titanium precursor. Additionally, stepped evaporation and heating processes were adopted to control the condensation rate and facilitate the assembly of the ordered mesostructure, and ensure the formation of fully polycrystalline anatase titania frameworks without collapse of the mesostructure. By employing the obtained mesoporous and crystallized TiO₂ as the photoanode in a dye‐sensitized solar cell, a high power‐conversion efficiency (5.45%) can be achieved in combination with the N719 dye, which shows that this mesoprous titania is a great potential candidate as a catalyst support for photonic‐conversion applications.     

长效促胰岛素降糖酵母的构建及其对糖尿病模型小鼠的治疗效果

益生菌生物药物是指通过口服表达药用多肽(蛋白)的重组益生菌活细胞达到治疗疾病的新型口服给药系统。为了构建一种能有效防治2型糖尿病的酵母生物药物,文章首先构建了酿酒酵母(S.cerevisiae)整合型表达载体pNK1-PGK,并且通过绿色荧光蛋白(GFP)证明其表达功能正常,利用该载体将10×GLP-1 (Glucagon-like peptide-1)基因转化到酿酒酵母INVSc1中,通过营养缺陷型和Western blotting成功筛选出表达10×GLP-1的长效促胰岛素降糖酵母(Long-acting GLP-1 hypoglycemic yeast, LHY)。该酵母生长迅速,外源基因10×GLP-1表达稳定,表达量达到1.56 mg/g细胞湿重。通过链脲佐菌素和高脂高糖饮食联合诱导的方法构建了2型糖尿病小鼠模型,用LHY对其进行口服灌胃治疗,证明LHY具有较好疗效,明显降低血糖水平。     

Increased stability of Bcl-2 in HSP70-mediated protection against apoptosis induced by oxidative stress

We have previously shown that heat shock protein 70 (HSP70) markedly inhibits H₂O₂-induced apoptosis in mouse C2C12 myogenic cells by reducing the release of Smac. However, the molecular mechanism by which HSP70 interferes with Smac release during oxidative stress-induced apoptosis is not understood. In the current study, we showed that HSP70 increased the stability of Bcl-2 during oxidative stress. An antisense phosphorothioate oligonucleotide against Bcl-2 caused selective inhibition of Bcl-2 protein expression induced by HSP70 and significantly attenuated HSP70-mediated cell protection against H₂O₂-induced release of Smac and apoptosis. Taken together, our results indicate that there are important relationships among HSP70, Bcl-2, release of Smac, and induction of apoptosis by oxidative stress.     

Effect of marriage on duration of chest pain associated with acute myocardial infarction before seeking care

Background:

Coronary artery disease is the most common cause of death in the Western world, and being married decreases the risk of death from cardiovascular causes. We aimed to determine whether marital status was a predictor of the duration of chest pain endured by patients with acute myocardial infarction before they sought care and whether the patient’s sex modified the effect.

Methods:

We conducted a retrospective, population-based cohort analysis of patients with acute myocardial infarction admitted to 96 acute care hospitals in Ontario, Canada, from April 2004 to March 2005. We excluded patients who did not experience chest pain. Using multivariable regression analyses, we assessed marital status in relation to delayed presentation to hospital (more than six hours from onset of pain), both overall and stratified by sex. In patients who reported the exact duration of chest pain, we assessed the effect of marital status on the delay in seeking care.

Results:

Among 4403 eligible patients with acute myocardial infarction, the mean age was 67.3 (standard deviation 13.6) years, and 1486 (33.7%) were women. Almost half (2037 or 46.3%) presented to a hospital within two hours, and 3240 (73.6%) presented within six hours. Overall, 75.3% (2317/3079) of married patients, 67.9% (188/277) of single patients, 68.5% (189/276) of divorced patients and 70.8% (546/771) of widowed patients presented within six hours of the onset of chest pain. Being married was associated with lower odds of delayed presentation (odds ratio [OR] 0.46, 95% confidence interval [CI] 0.30–0.71, p < 0.001) relative to being single. Among men, the OR was 0.35 (95% CI 0.21–0.59, p < 0.001), whereas among women the effect of marital status was not significant (OR 1.36, 95% CI 0.49–3.73, p = 0.55).

Interpretation:

Among men experiencing acute myocardial infarction with chest pain, being married was associated with significantly earlier presentation for care, a benefit that was not observed for married women. Earlier presentation for medical care appears to be one reason for the observed lower risk of cardiovascular death among married men, relative to their single counterparts.Marriage has long been known to offer health benefits^1,2 and is associated with a lower risk of death^3,4 relative to people who are not married. The effect is more pronounced among men than among women.^5,6 However, the specific mechanisms responsible for the lower rate of cardiovascular deaths in married persons⁷ are not known.Effective, time-sensitive therapy for acute myocardial infarction is available,^8,9 and delays in the emergency department and for in-hospital components of care have been substantially reduced over the past few decades.^10,11 In contrast, patients’ delay in seeking care for acute myocardial infarction has shown little improvement over time,^12,13 despite intensive campaigns to raise public awareness.^14,15 Patients’ delay remains by far the largest component of the overall delay between onset of symptoms and receipt of therapy.¹⁶ No study has examined the effect of marital status on patients’ delay, and only a few small studies have examined predictors of this component of delay by sex.^17,18We examined the effect of marital status, a social factor, on the time from onset of chest pain to arrival in an emergency department or hospital, in a population-based cohort of patients with acute myocardial infarction. We hypothesized that being married or in a common-law relationship would be associated with less delay, because we surmised that a spouse would encourage earlier pursuit of medical care, either directly or indirectly (i.e., even if the spouse was not physically present during the symptoms, his or her existence might spur the patient to seek care earlier). We hypothesized that wives would be more likely than husbands to assume the caregiver role and that the beneficial effect of marriage would therefore be stronger among men than among women.     

Investigation of peat sediments from Daiyun Mountain in southeast China: late Holocene vegetation,climate and human impact

In this study, late Holocene vegetation, climate and human impacts were investigated using multiproxy data-pollen percentages, pollen accumulation rates (PAR), humification and loss-on-ignition (LOI)—measured from peat sediments from Daiyun Mountain, southeast China. A stratigraphic chronology was established on the basis of four radiocarbon dates. The 4,350 year sequence of vegetation history and climate change exhibits three distinctive stages: (1) 4,350–1,000 cal bp, during which the vegetation was dominated by evergreen forests mainly composed of broad-leaf trees, indicating a warm and wet climate; (2) 1,000–550 cal bp, during which the climate was thought to be cool and dry, based on a decrease in pollen percentages and the PARs of trees, shrubs and wetland herbs, and an increase in the pollen percentage and PAR of dry land herbs, as well as high overall LOI values; and (3) 550 cal bp to modern times, during which higher pollen percentages of dry land and wetland herbs, along with low pollen percentage and PAR of trees and shrubs, as well as low absorbance and LOI values, suggest relatively cooler but wetter climate conditions. In addition, major climatic events, such as the warm period from ad 670–960, the Medieval Warm Period (ad 1050–1520) and the Little Ice Age (ad 1580–1850), could be identified within the peat sediments in this study, with climatic conditions at these times being characteristically warm and wet, warm and dry, and cold and wet, respectively. Pollen signals indicate significant human impact since 1,000 cal bp, which may be linked to the development of the local porcelain industry and a rapid increase in the population in the study region.     

Cx36 expression in the AII‐mediated rod pathway is activity dependent in the developing rabbit retina

Gap junctions are composed of connexin 36 (Cx36) and play a critical role in the rod photoreceptor signaling pathways of the vertebrate retina. Despite the fact that their connection and modulation in various rod pathways have been extensively studied in adult animals, little is known about the contribution and regulation of gap junctions to the development of the AII amacrine cell (AC)‐mediated rod pathway. Using immunohistochemistry and microinjection, this study demonstrates a steady increase in relative Cx36 protein expression in both plexiform layers of the rabbit retina at around the time of eye opening. However, immediately after eye opening, most Cx36 immunoreactive AII ACs show no gap junction coupling pattern to neighboring cells and it is not until the third postnatal week that AII cells begin to exhibit an adult‐like tracer‐coupling pattern. Moreover, studies using dark‐rearing and AMPA receptor blockade during postnatal development both revealed that relative levels of Cx36 immunoreactivity in AII ACs were increased when neural activity was inhibited . Our findings suggest that Cx36 expression in the AII‐mediated rod pathway is activity dependent in the developing rabbit retina . © 2015 Wiley Periodicals, Inc. Develop Neurobiol 76: 473–486, 2016