Brønsted Acid-Catalyzed Intramolecular Tandem Double Cyclization of γ-Hydroxy Acetylenic Ketones with Alkynes into Naphtho[1,2-b]furan-3-ones.

A metal-free and atom-economic route for the synthesis of naphtho[1,2-b]furan-3-ones has been realized via p-TsOH·H2O-catalyzed intramolecular tandem double cyclization of γ-hydroxy acetylenic ketones with alkynes in formic acid. The benzene-linked furanonyl-ynes are the key intermediates obtained by the scission/recombination of C-O double bonds. Further, the structural modifications of the representative product were implemented by reduction, demethylation, substitution, and [5 + 2]-cycloaddition.

The FATZO mouse, a next generation model of type 2 diabetes, develops NAFLD and NASH when fed a Western diet supplemented with fructose.

BACKGROUND: Metabolic disorders such as insulin resistance, obesity, and hyperglycemia are prominent risk factors for the development of non-alcoholic fatty liver disease (NAFLD)/steatohepatitis (NASH). Dietary rodent models employ high fat, high cholesterol, high fructose, methionine/choline deficient diets or combinations of these to induce NAFLD/NASH. The FATZO mice spontaneously develop the above metabolic disorders and type 2 diabetes (T2D) when fed with a normal chow diet. The aim of the present study was to determine if FATZO mice fed a high fat and fructose diet would exacerbate the progression of NAFLD/NASH. METHODS: Male FATZO mice at the age of 8 weeks were fed with high fat Western diet (D12079B) supplemented with 5% fructose in the drinking water (WDF) for the duration of 20 weeks. The body weight, whole body fat content, serum lipid profiles and liver function markers were examined monthly along with the assessment of liver histology for the development of NASH. In addition, the effects of obeticholic acid (OCA, 30 mg/kg, QD) on improvement of NASH progression in the model were evaluated. RESULTS: Compared to normal control diet (CD), FATZO mice fed with WDF were heavier with higher body fat measured by qNMR, hypercholesterolemia and had progressive elevations in AST (~ 6 fold), ALT (~ 6 fold), liver over body weight (~ 2 fold) and liver triglyceride (TG) content (1.4-2.9 fold). Histological examination displayed evidence of NAFLD/NASH, including hepatic steatosis, lobular inflammation, ballooning and fibrosis in FATZO mice fed WDF. Treatment with OCA for 15 weeks in FATZO mice on WDF significantly alleviated hypercholesterolemia and elevation of AST/ALT, reduced liver weight and liver TG contents, attenuated hepatic ballooning, but did not affect body weight and blood TG levels. CONCLUSION: WDF fed FATZO mice represent a new model for the study of progressive NAFLD/NASH with concurrent metabolic dysregulation.

Effect of addition of melatonin on liquid storage of ram semen at 4°C.

Adding a certain amount of antioxidants to semen extender has been shown to improve semen quality. The aim of present study was to elucidate whether the supplementation of melatonin to the Tris-based extender (CTR) could enhance the quality of ram spermatozoa during storage at 4°C. Ram semen samples were collected and diluted with CTR extender containing different concentrations (0, 0.05 (M 0.05), 0.1 (M 0.1), 0.2 (M 0.2) or 0.4 (M 0.4) mM) of melatonin. Sperm routine indicators, mitochondrial activity, total antioxidant capacity (T-AOC) and malondialdehyde (MDA) content were analysed in control and melatonin treatment groups. The higher per cent of motility, plasma membrane integrity, mitochondrial activity and T-AOC activity was observed in M 0.05, M 0.1 and M 0.2 groups compared to control group at 5 days of storage (p < 0.05), while lower percentage of MDA content was observed among these groups (p < 0.05). In addition, there were no significant differences in acrosome integrity among the control and M 0.05, M 0.1 and M 0.2 groups during the experiment. The above results show that the addition of 0.05, 0.1, 0.2 mM of melatonin is beneficial to the preservation of ram semen during liquid storage at 4°C mainly through antioxidative stress.

Low-density point eating algorithm for surface reconstruction from dense scans.

We present a low-density point eating algorithm for surface reconstruction from dense scans. First, the density map for each scan is estimated and the boundary densities are down-weighted. Subsequently, the poorly scanned low-density overlapping points are eaten up based on a user-specified threshold. Finally, the overlapping areas are thinned by using the moving least-squares operator and the homogeneous points are weighted averaged. The new algorithm can extract smooth but detailed point set surfaces that are as close as possible to the ground truth. The good performance of the new algorithm is demonstrated by comparison with several advanced surface reconstruction algorithms.

Exposure-fusion-based dot-grid image acquisition and recognition for sheet metal strain analysis.

Dot-grid images are usually captured for grid strain analysis during sheet metal forming. Due to the strong reflective characteristic of the metallic surfaces, the recorded dot-grid images often have poor quality, low positioning accuracy, and low recognition rate. Therefore, an exposure-fusion-based dot-grid image acquisition and recognition approach is proposed. First, multiple dot-grid images are captured at different exposure levels. Subsequently, the recorded multi-exposure dot-grid images are fused into a new high-quality dot-grid image based on exposure fusion technology. Finally, a dot-grid image recognition procedure is developed to detect the dot-grids in the new dot-grid image. Both synthetic and real dot-grid images were tested to verify the performance of the novel approach. When synthetic dot-grid images were tested, the maximum positioning error was up to 6.044 pixels if they were recognized in the traditional way, whereas the maximum positioning error was reduced to 0.132 pixels if the novel approach was adopted. When real dot-grid images were tested, the lowest recognition rate is only 50.52% if they were recognized in the traditional way. Nevertheless, the recognition rate can reach about 91% if the novel approach was employed. These experimental results show the superiorities of the novel approach.

Integrating novel chemical weapons and evolutionarily increased competitive ability in success of a tropical invader.

The evolution of increased competitive ability (EICA) hypothesis and the novel weapons hypothesis (NWH) are two non-mutually exclusive mechanisms for exotic plant invasions, but few studies have simultaneously tested these hypotheses. Here we aimed to integrate them in the context of Chromolaena odorata invasion. We conducted two common garden experiments in order to test the EICA hypothesis, and two laboratory experiments in order to test the NWH. In common conditions, C. odorata plants from the nonnative range were better competitors but not larger than plants from the native range, either with or without the experimental manipulation of consumers. Chromolaena odorata plants from the nonnative range were more poorly defended against aboveground herbivores but better defended against soil-borne enemies. Chromolaena odorata plants from the nonnative range produced more odoratin (Eupatorium) (a unique compound of C. odorata with both allelopathic and defensive activities) and elicited stronger allelopathic effects on species native to China, the nonnative range of the invader, than on natives of Mexico, the native range of the invader. Our results suggest that invasive plants may evolve increased competitive ability after being introduced by increasing the production of novel allelochemicals, potentially in response to naïve competitors and new enemy regimes.

Metformin improves sheep sperm cryopreservation via vitalizing the AMPK pathway.

Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is a key regulator of sperm function and physiological metabolism. Metformin, an inexpensive and effective antioxidant, is known to play an important role in the activation of AMPK. Therefore metformin has potential to improve sperm cryopreservation. The aim of this study was to investigate the effect of metformin during semen cryopreservation of sheep and to find the most effective concentration in freezing extender. Semen were cryopreserved with extender containing different concentrations of metformin (0, 0.25, 0.5, 1.0, 2.0 and 4.0 mmol/L). Sperm motility, acrosome integrity and plasma membrane integrity were measured after semen freezing and thawing. All results showed that sperm quality was significantly increased in the 1.0 mmol/L metformin-treated group compared with the control group (P < 0.05). In addition, the study showed that metformin effectively reduced the content of malondialdehyde (MDA) and reactive oxygen species (ROS), and increased the activity of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT) and total antioxidant capacity (T-AOC) of freeze-thawed sperm (P < 0.05). The optimal concentration of metformin was 1.0 mmol/L. Moreover, the results showed that AMPK was localized in the acrosome region, junction and midsection of sperm, and p-AMPK was distributed in the post-acrosomal region, junction and midsection. Western blot analysis indicated that 1.0 mmol/L metformin stimulated the phosphorylation of AMPK in sperm. Further results showed that 1.0 mmol/L metformin significantly increased the mitochondrial membrane potential (ΔΨm), ATP content, glucose uptake and lactate efflux of post-thawed sperm through the AMPK pathway, improved sperm quality, and increased the cleavage rate of in vitro fertilization (P < 0.05).

Recent advances in isolation, identification, and culture of mammalian spermatogonial stem cells.

Continuous spermatogenesis depends on the self-renewal and differentiation of spermatogonial stem cells (SSCs). SSCs, the only male reproductive stem cells that transmit genetic material to subsequent generations, possess an inherent self-renewal ability, which allows the maintenance of a steady stem cell pool. SSCs eventually differentiate to produce sperm. However, in an in vitro culture system, SSCs can be induced to differentiate into various types of germ cells. Rodent SSCs are well defined, and a culture system has been successfully established for them. In contrast, available information on the biomolecular markers and a culture system for livestock SSCs is limited. This review summarizes the existing knowledge and research progress regarding mammalian SSCs to determine the mammalian spermatogenic process, the biology and niche of SSCs, the isolation and culture systems of SSCs, and the biomolecular markers and identification of SSCs. This information can be used for the effective utilization of SSCs in reproductive technologies for large livestock animals, enhancement of human male fertility, reproductive medicine, and protection of endangered species.

[Spatial and Temporal Distribution Characteristics and Fugitive Dust Emission of Building Sites in Beijing].

Because of the continuous expansion of the city and the evacuation of non-core functions, the city pattern of Beijing has gradually changed in recent years. Based on many construction projects, building sites are widely distributed within the city. Therefore, fugitive dust emission is an important factor affecting the air quality in Beijing. This article focuses on the plain area in Beijing. Remote sensing was used to extract building sites from 2013 to 2017, analyze the spatial and temporal distribution characteristics of the building sites, estimate the fugitive dust emission, and propose a grid-based emission classification management program. Research shows that the building sites form a belt surrounding the central urban area, mainly distributed in the urban-rural integration area. From 2013 to 2017, the area of the building sites first decreased and then increased. After 2015, the center of the building sites in Beijing shifted to the southeast and started to show an uneven distribution. The area of the building sites is positively correlated with the PM10 concentration. The correlation coefficients of 23 automatic ground monitoring stations are all above 0.80. Combined with the building site activity levels and emission factors, the estimated air pollutant emissions of TSP, PM10, and PM2.5 from building sites in 2017 were 39.5×104, 19.4×104, and 4.0×104 t, respectively. The emission intensity of the pollution in the grid has developed towards polarization, which further increased the emission intensity of high-strength pollution grids. Based on standardized PM10 grid emissions of building suites, the plain area of Beijing can be divided into five categories:lower pollution, low pollution, medium pollution, high pollution, and higher pollution.

[Estimation of Coal Consumption and the Emission of Related Contaminants in the Plain Area Around Beijing During 2015-2017].

Spatial distribution of bungalow areas in the plain area of Beijing was interpreted using high resolution remote sensing images from 2015-2017, and data for the nearby surrounding areas was added in 2017. The bungalow development areas were then refined by a combination of field sampling and imagery interpretation. A statistical model was developed to estimate the coal consumption in bungalow areas based on statistical records of the developed areas. Emissions associated with coal burning emissions, namely, particulate matter (PM2.5), sulfur dioxide (SO2), and nitrogen oxide (NOx), were estimated from emission factors collected from the relevant research. The results showed that residential coal burning decreased drastically by 75% during the period 2015-2017 in Beijing. The effect of coal modification (gas) measures is remarkable. Beijing's six downtown districts, and the urban and rural areas of the southern plain, have eliminated coal use at this stage. The districts in which coal burning is centered are located in the northern plains of Beijing. Coal consumption is greater than 300000 t in the Changping, Shunyi district, and greater than 150000 t in the Pinggu, Yanqing District. The spatial distribution of coal consumption in 2015 was focused in the city center, then became a circular and later a semi-circular distribution. Coal burning was centered in the districts of Changping, Shunyi, Tongzhou, and Daxing, which are all located on the ring perimeter. The emissions of SO2 and NOx in the plain areas of Beijing were obviously different. The highest emissions of SO2 and NOx were observed in the Changping district, and reached 1113.3 t and 279.2 t, respectively. The Coal Clean Energy Policy in Baoding, Langfang in 2017 has achieved initial success. However, the coal consumption is very large; the quality of the coal was poor and coal was used extensively. The coal burning intensity showed an increasing trend from north to south in Baoding and Langfang. The coal consumption in Baoding and Langfang totaled 1043×104 t and 407×104 t respectively. The villages in the suburbs of Baoding and Langfang used less coal, with a coal consumption of less than 5×104 t in Beishi, Nanshi, and Xinshi villages. The spatial distribution of coal consumption for the Langfang plain was relatively even and uniform. The highest coal consumption was found in Wen'an, with a value of 69×104 t, and the lowest was observed in Dachang.

[Analysis of a Pollution Process in the Beijing-Tianjin-Hebei Region Based on Satellite and Surface Observations].

The air pollution control of the Beijing-Tianjin-Hebei region (BTH region) is gradually moving toward regional joint mode. Remote sensing technology can be used to realize real-time dynamic monitoring over a wide range of space and ground-based monitoring can obtain accurate point information. Combining satellite with ground-based data, the formation and dissipation of pollution can be traced in three dimensions. For this paper, we analyzed the formation process, transmission path, coverage area, and the meteorological characteristics of the pollution process over the BTH region during March 8-10, 2018, using satellite remote sensing data, surface PM2.5 concentration data, meteorological data, and lidar data. The results showed that an area of 200000 km2 was affected by this pollution process and that the grade of the pollution reached the fourth level (moderate pollution level). The regional transmission process was very typical in this process. During 8-9 March, the occurrence frequency of the southward wind was about 50% in the Beijing-Baoding region and 100% over the southern part of Hebei. With the help of continuous southward wind, the air quality of the Beijing-Baoding area rises from the first level to the fourth level. The high value area of aerosol optical thickness moved from the western part of the Handan-Xingtai region to the front of Yanshan Mountain. On 10 March, the weak north wind affected the region and the humidity increased obviously. A pollution convergence formed in the southern part of the BTH region. The center of pollution moved southward to the east part of the Handan-Xingtai Region. In the afternoon, with the help of the eastern wind, the air quality of Beijing got better from East to West. The vertical lidar observation results showed the pollution layer above Beijing was mainly below 1000 m. There were two inversion layers below 800 m and 1200-1500 m, respectively. The inversion temperature was as high as 4-7℃, which is unfavorable for vertical diffusion of pollutants. Thus, under the high intensity of regional energy consumption and pollution emissions background, the regional heavy pollution form easily once the weather conditions are bad.

Catalog of insect type specimens preserved at the Kunming Institute of Zoology, Chinese Academy of Science with corrections of some specimens.

This article presents a list of insect types preserved in Kunming Natural History Museum of Zoology (KNHMZ). As of March, 2015, 3 412 type specimens belonging to 266 species/subspecies of 37 families in 9 orders (Odonata, Isoptera, Mantodea, Orthoptera, Hemiptera, Coleoptera, Diptera, Hymenoptera and Lepidoptera) are included. Information corrections of some specimens are provided in this article.

[Ecological risk assessment of human activity of rapid economic development regions in southern Jiangsu, China: a case study of Dantu District of Zhenjiang City].

This article investigated the spatiotemporal variation of landscape ecological risk in Dantu District of Zhenjiang City with statistical method based on the ETM remote sensing data in 2000 and 2005, and the TM remote sensing data in 2010, and quantitative index of regional ecological risk assessment was established with the employment of landscape index, so as to enhance the ecosystem management, prevent and reduce the regional ecological risk in southern Jiangsu with rapid economic development. The results showed that the fragmentations, divergence, and ecological losses of natural landscape types, such as forestland, wetland, waters, etc., were deteriorated with the expansion of built-up lands from 2000 to 2010. The higher ecological risk zone took up 5.7%, 9.0%, and 10.2% of the whole region in 2000, 2005, and 2010, respectively, which mainly distributed in the plain hilly region. During the study period, the area aggravating to the higher ecological risk zone was approximately 296.2 km2, 48% of the whole region. The ecological risk rose up in most of the region. The interference of rapid economic development to landscape patterns was even more intensive, with obvious spatial differences in ecological risk distribution. The measures of exploiting resources near the port, utilizing natural wetlands, constructing industrial parks, and rapid urbanization, etc., intensified the ecological risk and accelerated the conversion rate. Prompt strategies should be established to manage the ecological risk of this region.

A highly selective ratiometric fluorescent chemosensor for Cd2+ ions.

A phenanthroxazole-based fluorescent sensor for Cd(2+) has been developed. Of particular significance is the specific ratiometric response of the sensor toward Cd(2+) without interference from other biologically important metal ions including Zn(2+). The test paper made of this sensor exhibits both absorption and fluorescent color changes when exposed to Cd(2+) aqueous solution.

A highly selective and sensitive luminescent chemosensor for Zn2+ ions based on cyclometalated platinum(II) complexes.

A novel luminescent Zn(2+) ions chemosensor, a cyclometalated platinum(II) bipyridyl acetylide complex, was designed. Of particular significance is that it shows a high sensitivity towards Zn(2+) ions without interference from other biologically important cations in acetonitrile. The tautomerization of amide favors detecting Zn(2+) ions among other HTM (heavy and transition metal) ions in aqueous systems.