Circle packings and total geodesic curvatures in hyperbolic background geometry

In this paper, we study a new type of circle packings in hyperbolic background geometry. Horocycles and hypercycles are also considered in this packing. We give the existence and rigidity of this type of circle packing with conical singularities in terms of the total geodesic curvature. Moreover, we introduce the combinatorial curvature flow on surfaces to find the desired circle packing with the prescribed total geodesic curvature

The recombinant adeno-associated virus vector (rAAV2)-mediated apolipoprotein B mRNA-specific hammerhead ribozyme: a self-complementary AAV2 vector improves the gene expression

BACKGROUND: In humans, overproduction of apolipoprotein B (apoB) is positively associated with premature coronary artery diseases. To reduce the levels of apoB mRNA, we have designed an apoB mRNA-specific hammerhead ribozyme targeted at nucleotide sequences GUA(6679 )(RB15) mediated by adenovirus, which efficiently cleaves and decreases apoB mRNA by 80% in mouse liver and attenuates the hyperlipidemic condition. In the current study, we used an adeno-associated virus vector, serotype 2 (AAV2) and a self-complementary AAV2 vector (scAAV2) to demonstrate the effect of long-term tissue-specific gene expression of RB15 on the regulation apoB mRNA in vivo. METHODS: We constructed a hammerhead ribozyme RB15 driven by a liver-specific transthyretin (TTR) promoter using an AAV2 vector (rAAV2-TTR-RB15). HepG2 cells and hyperlipidemic mice deficient in both the low density lipoprotein receptor and the apoB mRNA editing enzyme genes (LDLR-/-Apobec1-/-; LDb) were transduced with rAAV2-TTR-RB15 and a control vector rAAV-TTR-RB15-mutant (inactive ribozyme). The effects of ribozyme RB15 on apoB metabolism and atherosclerosis development were determined in LDb mice at 5-month after transduction. A self-complementary AAV2 vector expressing ribozyme RB15 (scAAV2-TTR-RB15) was also engineered and used to transduce HepG2 cells. Studies were designed to compare the gene expression efficiency between rAAV2-TTR-RB15 and scAAV2-TTR-RB15. RESULTS: The effect of ribozyme RB15 RNA on reducing apoB mRNA levels in HepG2 cells was observed only on day-7 after rAAV2-TTR-RB15 transduction. And, at 5-month after rAAV2-TTR-RB15 treatment, the apoB mRNA levels in LDb mice were significantly decreased by 43%, compared to LDb mice treated with control vector rAAV2-TTR-RB15-mutant. Moreover, both the rAAV2-TTR-RB15 viral DNA and ribozyme RB15 RNA were still detectable in mice livers at 5-month after treatment. However, this rAAV2-TTR-RB15 vector mediated a prolonged but low level of ribozyme RB15 gene expression in the mice livers, which did not produce the therapeutic effects on alteration the lipid levels or the inhibition of atherosclerosis development. In contrast, the ribozyme RB15 RNA mediated by scAAV2-TTR-RB15 vector was expressed immediately at day-1 after transduction in HepG2 cells. The apoB mRNA levels were decreased 47% (p = 0.001), compared to the control vector scAAV2-TTR-RB15-mutant. CONCLUSION: This study provided evidence that the rAAV2 single-strand vector mediated a prolonged but not efficient transduction in mouse liver. However, the scAAV2 double-strand vector mediated a rapid and efficient gene expression in liver cells. This strategy using scAAV2 vectors represents a better approach to express small molecules such as ribozyme

Spatial Distribution Characteristics and Evolution Pattern of Air Quality in Henan Province

Urban air pollution is an urgent problem to be solved in the process of rapid urbanization and economic development in China. Based on the daily average data of urban air quality index of Henan province from 2015.1 to 2018.12, this paper utilizes cluster analysis, trend surface analysis and centralizing evolution analysis methods to study the spatial distribution characteristics and evolution pattern of urban air quality in the province. The results show that the air quality in the province presents five air quality systems, which seriously relate to the terrain, the air quality index of the northern cities has always been higher than that of the southern cities, with the latitude increases, the air quality index gradually increases, and the increase rate in the middle region is significantly higher than that in both sides. The province weathers, in the study period, shows 4 grades as good & moderate, lightly polluted, moderately polluted and heavily polluted. Lightly polluted weathers first appear in central and southern cities, moderately polluted and heavily polluted weather first appear in the northern cities, and then spread to the rest cities of the province

Correlation Analysis of Main Pollutant Concentration-A Case Study of Zhengzhou

Air pollution is one of the main problems to be solved in the sustainable development of China's economy, its main pollution components include PM2.5, PM10, SO2, NO2, CO and O3, the pollution component governance is an effective means of atmospheric environmental management. Based on the monitor data of six main pollutant concentrations in Zhengzhou from 2015 to 2018, this paper analyzes the correlation characteristics between their concentrations by using correlation analysis, the multiple correlation characteristics of the one pollutant concentration with the other five pollutant concentrations by using multiple correlation analysis, the independent linear interpretation ratio between the six pollutant concentrations by using partial correlation analysis, at last, a pollutant independent emission index is defined to describe the independent emission level of one pollutant, then utilize the index to study the distribution characteristics of six main pollution concentrations in the study period in Zhengzhou. The results show that there is a significant correlation between the six pollutant concentrations. PM2.5, O3 and PM10 are the primary pollutants in Zhengzhou, the PM2.5 concentration is controlled by PM10 concentration and CO concentration, similarly, the PM10 concentration is controlled by PM2.5 concentration. In the polluted weather, O3 has the highest level of independent emissions. The main task of Zhengzhou in pollutant composition governance is to control the emission of PM2.5 and O3

Ispitivanje antioksidativne aktivnosti in vitro polipeptida meduze (Rhopilema esculentum)

Jellyfish gelatin was hydrolyzed by different proteases to obtain antioxidative polypeptides. The gelatin hydrolysate obtained by progressive hydrolysis using trypsin and Properase E exhibited the highest hydrolysis degree and antioxidant activity. Three series of gelatin polypeptides (SCP1, SCP2 and SCP3) were obtained by ultrafiltrating the gelatin hydrolysate through molecular mass cut-off membranes of 10, 6 and 2 kDa, respectively. Amino acid composition analysis showed that SCP3 had the highest total hydrophobic amino acid content. The in vitro antioxidant tests demonstrated that SCP2 had the strongest hydroxyl radical and hydrogen peroxide scavenging activities and metal chelating ability, while SCP3 showed the highest reducing power, antioxidant activity in linoleic acid emulsion system and superoxide anion radical scavenging activity. The results support the feasibility of jellyfish gelatin as a natural antioxidant polypeptide provider, and enzymatic hydrolysis and ultrafiltration could be potent future processing technologies to utilize the abundant jellyfish resource.Hidrolizom želatine iz meduze pomoću različitih proteaza dobiveni su polipeptidi antioksidativnih svojstava. Najveći stupanj hidrolize i najbolja antioksidativna svojstva imao je hidrolizat dobiven progresivnom hidrolizom pomoću tripsina i Properase E. Ultrafiltracijom hidrolizata kroz membrane (10, 6 i 2 kDa) dobivene su tri serije polipeptida želatine: SCP1, SCP2 i SCP3. Analizom aminokiselinskoga sastava ustanovljeno je da SCP3 ima najveći ukupni udio hidrofobnih aminokiselina. Antioksidativni testovi in vitro pokazali su da SCP2 ima najveću sposobnost uklanjanja hidroksilnih radikala i vodikova peroksida te keliranja metala, a SCP3 najveću redukcijsku moć, najbolju antioksidativnu aktivnost u emulzijskom sustavu linoleinske kiseline te sposobnost uklanjanja superoksidnih aniona. Rezultati potvrđuju da se želatina iz meduze može upotrijebiti kao izvor prirodnih antioksidativnih polipeptida, a enzimska hidroliza i ultrafiltracija kao postupci prerade za njezino iskorištavanje

Ispitivanje antioksidativne aktivnosti in vitro polipeptida meduze (Rhopilema esculentum)

Jellyfish gelatin was hydrolyzed by different proteases to obtain antioxidative polypeptides. The gelatin hydrolysate obtained by progressive hydrolysis using trypsin and Properase E exhibited the highest hydrolysis degree and antioxidant activity. Three series of gelatin polypeptides (SCP1, SCP2 and SCP3) were obtained by ultrafiltrating the gelatin hydrolysate through molecular mass cut-off membranes of 10, 6 and 2 kDa, respectively. Amino acid composition analysis showed that SCP3 had the highest total hydrophobic amino acid content. The in vitro antioxidant tests demonstrated that SCP2 had the strongest hydroxyl radical and hydrogen peroxide scavenging activities and metal chelating ability, while SCP3 showed the highest reducing power, antioxidant activity in linoleic acid emulsion system and superoxide anion radical scavenging activity. The results support the feasibility of jellyfish gelatin as a natural antioxidant polypeptide provider, and enzymatic hydrolysis and ultrafiltration could be potent future processing technologies to utilize the abundant jellyfish resource.Hidrolizom želatine iz meduze pomoću različitih proteaza dobiveni su polipeptidi antioksidativnih svojstava. Najveći stupanj hidrolize i najbolja antioksidativna svojstva imao je hidrolizat dobiven progresivnom hidrolizom pomoću tripsina i Properase E. Ultrafiltracijom hidrolizata kroz membrane (10, 6 i 2 kDa) dobivene su tri serije polipeptida želatine: SCP1, SCP2 i SCP3. Analizom aminokiselinskoga sastava ustanovljeno je da SCP3 ima najveći ukupni udio hidrofobnih aminokiselina. Antioksidativni testovi in vitro pokazali su da SCP2 ima najveću sposobnost uklanjanja hidroksilnih radikala i vodikova peroksida te keliranja metala, a SCP3 najveću redukcijsku moć, najbolju antioksidativnu aktivnost u emulzijskom sustavu linoleinske kiseline te sposobnost uklanjanja superoksidnih aniona. Rezultati potvrđuju da se želatina iz meduze može upotrijebiti kao izvor prirodnih antioksidativnih polipeptida, a enzimska hidroliza i ultrafiltracija kao postupci prerade za njezino iskorištavanje

Fractional quantum Hall effect in the absence of Landau levels

It has been well-known that topological phenomena with fractional excitations, i.e., the fractional quantum Hall effect (FQHE) \cite{Tsui1982} will emerge when electrons move in Landau levels. In this letter, we report the discovery of the FQHE in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically nontrivial flat band model on the checkerboard lattice \cite{sun}. In the presence of nearest-neighboring repulsion ($U$), we find that at 1/3 filling, the Fermi-liquid state is unstable towards FQHE. At 1/5 filling, however, a next-nearest-neighboring repulsion is needed for the occurrence of the 1/5 FQHE when $U$ is not too strong. We demonstrate the characteristic features of these novel states and determine the phase diagram correspondingly.Comment: 6 pages and 4 figure

Topological semimetal in a fermionic optical lattice

Optical lattices play a versatile role in advancing our understanding of correlated quantum matter. The recent implementation of orbital degrees of freedom in chequerboard and hexagonal optical lattices opens up a new thrust towards discovering novel quantum states of matter, which have no prior analogs in solid state electronic materials. Here, we demonstrate that an exotic topological semimetal emerges as a parity-protected gapless state in the orbital bands of a two-dimensional fermionic optical lattice. The new quantum state is characterized by a parabolic band-degeneracy point with Berry flux $2\pi$, in sharp contrast to the $\pi$ flux of Dirac points as in graphene. We prove that the appearance of this topological liquid is universal for all lattices with D$_4$ point group symmetry as long as orbitals with opposite parities hybridize strongly with each other and the band degeneracy is protected by odd parity. Turning on inter-particle repulsive interactions, the system undergoes a phase transition to a topological insulator whose experimental signature includes chiral gapless domain-wall modes, reminiscent of quantum Hall edge states.Comment: 6 pages, 3 figures and Supplementary Informatio

Burden of falls attributable to low bone mineral density among people aged 60 years and over in China from 1990 to 2019

ObjectiveFalls in older people have become a major public health, economic and societal problem. Osteoporosis predisposes older adults to high risk of falls, which were the most common outcome attributable to low bone mineral density (LBMD). In this study, we analyze the long-term trends in falls burden attributable to LBMD among people aged 60 years and over from 1990 to 2019, using data from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019).MethodsData from GBD 2019 were used to assess the long-term trends in mortality and disability-adjusted life-year (DALY) rates by Joinpoint regression. The age-period-cohort (APC) model was used to evaluate the effects of age, period and cohort on mortality rate of falls attributable to LBMD.ResultsThe mortality and DALYs rates of falls attributable to LBMD among people aged 60 years and over increased from 1990 to 2019, with average annual percentage changes (AAPCs) of 1.74% (95% CI: −1.47 to 2.01%) and 0.99% (95% CI: 0.80–1.19%), respectively. APC analysis revealed that the mortality rate due to LBMD significantly increased among the older people over the age of 75 years. The risk of falls mortality due to LBMD during the period of 1990–2019 initially declined but later elevated. An overall increasing risk for falls death attributable to LBMD was presented across birth cohorts, but in cohorts born after 1930, the upward trend has slowed down. The overall net drift per year attributable to LBMD was above 0. The corresponding results showed that the negative impact of period and cohort effects among males was more pronounced than those among females.ConclusionsFalls attributable to LBMD remain an ongoing health burden in the older people in China, and the mortality has been on the rise from 1990 to 2019, especially among the older people aged 80+ years group. The prevention and treatment of LBMD should be emphasized, especially among males and oldest-old people. Furthermore, there is an urgent need to strengthen the implementation of system-wide, integrated and effective public health policies and other health interventions in China

Defining Security Requirements with the Common Criteria: Applications, Adoptions, and Challenges

Advances of emerging Information and Communications Technology (ICT) technologies push the boundaries of what is possible and open up new markets for innovative ICT products and services. The adoption of ICT products and systems with security properties depends on consumers' confidence and markets' trust in the security functionalities and whether the assurance measures applied to these products meet the inherent security requirements. Such confidence and trust are primarily gained through the rigorous development of security requirements, validation criteria, evaluation, and certification. Common Criteria for Information Technology Security Evaluation (often referred to as Common Criteria or CC) is an international standard (ISO/IEC 15408) for cyber security certification. In this paper, we conduct a systematic review of the CC standards and its adoptions. Adoption barriers of the CC are also investigated based on the analysis of current trends in security evaluation. Specifically, we share the experiences and lessons gained through the recent Development of Australian Cyber Criteria Assessment (DACCA) project that promotes the CC among stakeholders in ICT security products related to specification, development, evaluation, certification and approval, procurement, and deployment. Best practices on developing Protection Profiles, recommendations, and future directions for trusted cybersecurity advancement are presented