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This study aimed to assess the prevalence of depression and anxiety in CHD patients and to explore the association between established cardiovascular risk factors and depression as well as anxiety. 2,216 patients with CHD confirmed by angiography were included in this cross-sectional study. Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder Scale (GAD-7) were used to assess depression and anxiety symptoms. The frequencies of individual depressive and anxiety symptoms grouped by age and gender were analyzed. Binary logistic regression analyses were used to identify cardiovascular risk factors associated with anxiety and depression. The overall prevalence rates of depression and anxiety in CHD patients were 8.2% and 5.4%, respectively. There were significant differences in the frequency of depression and anxiety symptoms between genders. However, age differences among individual depression and anxiety symptoms were insignificant. In multivariable analysis, female gender, smoking, and hyperlipidemia were associated with a more frequent depression occurrence, and female gender was associated with more frequent anxiety. Depression and anxiety were not associated with other cardiovascular risk factors. These findings suggest that a substantial proportion of CHD patients experienced anxiety and depression symptoms. Differences in depressive or anxiety symptoms among the distribution of individual symptoms need more attention. Depression was significantly associated with female gender, smoking, and hyperlipidemia. No anxiety symptom associations with cardiovascular risk factors were demonstrated to be significant except for the female. More research is needed to unravel the mechanisms of depression, anxiety, and cardiovascular disease.

The quantum orthogonal arrays define remarkable classes of multipartite entangled states called $k$-uniform states whose every reductions to $k$ parties are maximally mixed. We present constructions of quantum orthogonal arrays of strength 2 with levels of prime power, as well as some constructions of strength 3. As a consequence, we give infinite classes of 2-uniform states of $N$ systems with dimension of prime power $d\geq 2$ for arbitrary $N\geq 5$; 3-uniform states of $N$-qubit systems for arbitrary $N\geq 6$ and $N\neq 7,8,9,11$; 3-uniform states of $N$ systems with dimension of prime power $d\geq 7$ for arbitrary $N\geq 7$., 26 pages, 1 figures

The construction of nonlocal sets of quantum states has attracted much attention in recent years. We first introduce two Lemmas related to the triviality of orthogonality-preserving local measurements. Then we propose a general construction of nonlocal set of $n(d-1)+1$ orthogonal product states in $(\mathbb{C}^{d})^{\otimes n}$. The sets of nonlocal orthogonal product states are also put forward for the multipartite quantum systems with arbitrary dimensions. Our novel construction gives rise to nonlocal sets of orthogonal product states with much less members and thus reveals the phenomenon of nonlocality without entanglement more efficiently., Comment: 6 pages, 4 figures

Based on maximally entangled states, we explore the constructions of mutually unbiased bases in bipartite quantum systems. We present a new way to construct mutually unbiased bases by difference matrices in the theory of combinatorial designs. In particular, we establish $q$ mutually unbiased bases with $q-1$ maximally entangled bases and one product basis in $\mathbb{C}^q\otimes \mathbb{C}^q$ for arbitrary prime power $q$. In addition, we construct maximally entangled bases for dimension of composite numbers of non-prime power, such as five maximally entangled bases in $\mathbb{C}^{12}\otimes \mathbb{C}^{12}$ and $\mathbb{C}^{21}\otimes\mathbb{C}^{21}$, which improve the known lower bounds for $d=3m$, with $(3,m)=1$ in $\mathbb{C}^{d}\otimes \mathbb{C}^{d}$. Furthermore, we construct $p+1$ mutually unbiased bases with $p$ maximally entangled bases and one product basis in $\mathbb{C}^p\otimes \mathbb{C}^{p^2}$ for arbitrary prime number $p$., 24 pages

We develop a new technique to construct mutually unbiased tripartite absolutely maximally entangled bases. We first explore the tripartite absolutely maximally entangled bases and mutually unbiased bases in $\mathbb{C}^{d} \otimes \mathbb{C}^{d} \otimes \mathbb{C}^{d}$ based on mutually orthogonal Latin squares. Then we generalize the approach to the case of $\mathbb{C}^{d_{1}} \otimes \mathbb{C}^{d_{2}} \otimes \mathbb{C}^{d_{1}d_{2}}$ by mutually weak orthogonal Latin squares. The concise direct constructions of mutually unbiased tripartite absolutely maximally entangled bases are remarkably presented with generality. Detailed examples in $\mathbb{C}^{3} \otimes \mathbb{C}^{3} \otimes \mathbb{C}^{3},$ $\mathbb{C}^{2} \otimes \mathbb{C}^{2} \otimes \mathbb{C}^{4}$ and $\mathbb{C}^{2} \otimes \mathbb{C}^{5} \otimes \mathbb{C}^{10}$ are provided to illustrate the advantages of our approach.

In the manuscript, we proposed three entanglement protection schemes with environment-assisted measurements and weak measurement reversals. The result demonstrates that the entanglement of four-particle cluster state is disturbed by the amplitude damping channel, but the weak measurement reversal operation helps to preserve the entanglement of the final output quantum state. In particular, the entanglement will reach the maximum if the weak measurement reversal strength is equal to the amplitude damping magnitude. Compared with the previous protection protocols, the performance of our schemes is more practical.

Strong nonlocality with genuine entanglement was first shown by Wang et al using sets of GHZ-like states in tripartite quantum systems (2021 Phys. Rev. A 104, 012 424). However, it is an open problem whether there exists strong nonlocality with genuine entanglement in four or more partite systems. In this paper, we unify two different concepts of strong nonlocality introduced by Halder et al (2019 Phys. Rev. Lett. 122, 040 403) and by Zhang et al (2019 Phys. Rev. A 99, 062108). That is, we use a concept of k-strong nonlocality instead of these two different types of strong nonlocality. A set of orthogonal quantum states is k-strong nonlocal if it is locally irreducible in every k-partition. In fact, the strong nonlocality that is usually said is 2-strong nonlocality. The smaller the k is, the stronger the nonlocality will be. A set of states is k +-strong nonlocal if the strong nonlocality of this set is stronger than k-strong nonlocality but weaker than (k − 1)-strong nonlocality. Based on these concepts, firstly, we show 2-strong nonlocality with genuine entanglement by some sets of GHZ-like states with weight d in tripartite systems. These sets are not necessarily complete bases. Secondly, we present 2-strong nonlocality with genuine entanglement for systems with four or more parties. These results solve the open problem raised by Wang et al Finally, we construct a set of GHZ-like states with n +-strong nonlocality in n-partite quantum systems.

We study the constructions of nonlocal orthogonal product states in multipartite systems that cannot be distinguished by local operations and classical communication. We first present two constructions of nonlocal orthogonal product states in tripartite systems $$\mathcal {C}^{d}\otimes \mathcal {C}^{d}\otimes \mathcal {C}^{d}~(d\ge 3)$$ and $$\mathcal {C}^d\otimes \mathcal {C}^{d+1}\otimes \mathcal {C}^{d+2}~(d\ge 3)$$ . Then for general tripartite quantum system $$\mathcal {C}^{n_{1}}\otimes \mathcal {C}^{n_{2}}\otimes \mathcal {C}^{n_{3}}$$ $$(3\le n_{1}\le n_{2}\le n_{3})$$ , we obtain $$2(n_{2}+n_{3}-1)-n_{1}$$ nonlocal orthogonal product states. Finally, we put forward a new construction approach in $$\mathcal {C}^{d_{1}}\otimes \mathcal {C}^{d_{2}}\otimes \cdots \otimes \mathcal {C}^{d_{n}}$$ $$(d_1,d_2,\cdots d_n\ge 3,\, n>6)$$ multipartite systems. Remarkably, our indistinguishable sets contain less nonlocal product states than the existing ones, which improves the recent results and highlights their related applications in quantum information processing.

Background: Ischemic cardiovascular disease (ISCVD) is a massive public health problem. ISCVD risk prediction models based on traditional risk factors as predictors is limited. Carotid atherosclerosis plays a fundamental value in the occurrence of ISCVD. The aim of this study was to evaluate the value of risk stratification plus carotid plaque improving the prediction of ISCVD. Methods: Between June 2016 and June 2017, 3998 subjects with hypertension were prospectively recruited and completed traditional risk factors survey and carotid ultrasound measurements in Anzhen Hospital, Beijing, China. Results: A total of 2010 (50.3%) subjects were detected carotid plaque. Among patients free from ISCVD (n=3479), there were 884 patients (25.4%) at high risk for ISCVD, and 868 (25.0%), 1727 (49.6%) was classified as intermediate risk or low risk according to Chinese cardiovascular risk score chart. The detected rate of carotid plaque was 64.7%, 53.7%, and 38.5% among patients at high risk to low risk, respectively. Carotid plaques and risk stratification alone or in combination were significantly associated with ischemic stroke, and negatively correlated with coronary heart disease (all P>0.05). Adding carotid plaque to risk stratification, the ischemic stroke prevalence increased from 5.3% to 9.1% in the low-risk group (P=0.001), 5.4% to 12.3% in the intermediate-risk group (PConclusions: Carotid plaque has an important position as it plus risk stratification may improve the risk assessment of ischemic stroke and have resulted in reclassification.

In this paper, we present an offline arbitrated quantum blind dual-signature protocol by using four-particle entangled Greenberger-Horne-Zeilinger(GHZ) states. By using the special relationship of four-particle GHZ states, we can not only support the security of quantum signature, but also guarantee the anonymity of the message owner. In our protocol, the authority of the arbitrator has been reduced, i.e., he will not help the receiver verify the signature in the verification. Compared with the previous quantum blind signature protocols, the presented arbitrator is offline. Finally, the security analysis and discussion are proposed.

The joint-measurement (JM) attack is the most powerful threat to the database security for existing quantum-key-distribution (QKD)-based quantum private query (QPQ) protocols. Wei et al. (2016) [28] proposed a novel QPQ protocol against the JM attack. However, their protocol relies on two-way quantum communication thereby affecting its real implementation and communication efficiency. Moreover, it cannot ensure perfect user privacy. In this paper, we present a new one-way QPQ protocol in which the special way of classical post-processing of oblivious key ensures the security against the JM attack. Furthermore, it realizes perfect user privacy and lower complexity of communication.

In this paper, we investigate the indistinguishability of generalized Bell states (GBSs) by one-way local operations and classical communication (LOCC). We first introduce two sets, i.e., the difference set and the testing set, and show that the GBSs cannot always be distinguished by one-way LOCC if the testing set is a subset of the difference set of GBSs. Then we give a unified upper bound about indistinguishable GBSs by one-way LOCC. The newly derived bound is smaller than those presented in Zhang et al. [Phys. Rev. A 91, 012329 (2015)] and Wang et al. [Quantum Inf. Process. 15, 1661 (2016).]. More precisely, the minimum number of one-way locally indistinguishable GBSs is not more than $2\ensuremath{\lceil}\sqrt{d}\ensuremath{\rceil}+\ensuremath{\lceil}\frac{\sqrt{d}}{4}\ensuremath{\rceil}+1$.

We study the problem of quantum multi-unicastcommunication over the butterfly network in a quantum-walk architecture,where multiple arbitrary single-qubit states are transmitted simultaneouslybetween multiple source-sink pairs. Here, by introducing quantum walks, wedemonstrate a quantum multi-unicast communication scheme over the butterflynetwork and the inverted crown network, respectively, where the arbitrarysingle-qubit states can be efficiently transferred with both the probabilityand the state fidelity one. The presented result concerns only the butterflynetwork and the inverted crown network, but our techniques can be applied toa more general graph. It paves a way to combine quantum computation andquantum network communication.

In this paper, we mainly study the local distinguishability of mutually orthogonal maximally entangled states in canonical form. In $$d \otimes d$$d?d, Nathanson (Phys Rev A 88:062316, 2013) presented a feasible necessary and sufficient condition for distinguishing the general bipartite quantum states by one-way local operations and classical communication (LOCC). However, for maximally entangled states in canonical form, it is still unknown how to more effectively judge whether there exists a state such that those unitary operators corresponding to those maximally entangled states are pairwise orthogonal. In this work, we exhibit one method which can be used to more effectively judge it. Furthermore, we construct some sets of maximally entangled states and can easily know that those states are not distinguished by one-way LOCC with the help of our new method.

So far, very little is known about local indistinguishability of multipartite orthogonal product bases except some special cases. We first give a method to construct an orthogonal product basis with n parties each holding a $$\frac{1}{2}(n+1)$$ -dimensional system, where $$n\ge 5$$ and n is odd. The proof of the local indistinguishability of the basis exhibits that it is a sufficient condition for the local indistinguishability of an orthogonal multipartite product basis that all the positive operator-valued measure elements of each party can only be proportional to the identity operator to make further discrimination feasible. Then, we construct a set of n-partite product states, which contains only 2n members and cannot be perfectly distinguished by local operations and classic communication. All the results lead to a better understanding of the phenomenon of quantum nonlocality without entanglement in multipartite and high-dimensional quantum systems.

We investigate the upper bound on unambiguous discrimination by local operations and classical communication. We demonstrate that any set of linearly independent multipartite pure quantum states can be locally unambiguously discriminated if the number of states in the set is no more than $$\max \{d_{i}\}$$max{di}, where the space spanned by the set can be expressed in the irreducible form $$\otimes _{i=1}^{N}d_{i}$$?i=1Ndi and $$d_{i}$$di is the optimal local dimension of the $$i\hbox {th}$$ith party. That is, $$\max \{d_{i}\}$$max{di} is an upper bound. We also show that it is tight, namely there exists a set of $$\max \{d_{i}\}+1$$max{di}+1 states, in which at least one of the states cannot be locally unambiguously discriminated. Our result gives the reason why the multiqubit system is the only exception when any three quantum states are locally unambiguously distinguished.

Chen et al. (Phys Rev A 73:012303, 2006) constructed this "starlike cluster" state, which involves one qubit located at the center and n neighboring two-qubit arms. This genuine entangled state has been used for the construction of 2D and 3D cluster states, topological one-way computation, and dynamical quantum secret sharing. In this paper, we investigate the usefulness of this starlike cluster state and propose a theoretically extensible quantum digital signature scheme. The proposed scheme can be theoretically generalized to more than three participants. Moreover, it retains the merits of no requirements such as authenticated quantum channels and long-term quantum memory. We also give a security proof for the proposed scheme against repudiation and forgery.

Recently, the researches of quantum group signature (QGS) have attracted a lot of attentions and some typical protocols have been designed for e-payment system, e-government, e-business, etc. In this paper, we analyze the security of the quantum group signature with the example of two novel protocols. It can be seen that both of them cannot be implemented securely since the arbitrator cannot solve the disputes fairly. In order to show that, some possible attack strategies, which can be used by the malicious participants, are proposed. Moreover, the further discussions of QGS are presented finally, including some insecurity factors and improved ideas.

The security of the recent quantum multi-signature protocol based on teleportation is analyzed. We show that there are some security vulnerabilities in the protocol. The detailed attack strategies are described from the aspect of participant attack. We also point out that the protocol is not secure against external attack. Finally, we give some possible countermeasures to improve the protocol.

We propose a quantum protocol for the millionaire problem with Bell states, where two distrustful parties can compare the values of their fortune with the help of a semi-dishonest third party. The efficiency of our protocol is higher than that of previous protocols for millionaire problem. In our protocol, any information about the values of their fortune will not be leaked out. The security of our protocol is also discussed.

The security of a multi-user quantum communication network protocol using χ-type entangled states (Chang et al., J. Korean Phys. Soc. 61:1–5, 2012) is analyzed. We find that, by using one χ-type state in this protocol, two participants can only share 2 bits of information, not 4 bits as the authors stated. In addition, we give a special attack strategy by which an eavesdropper can elicit half of the secret information without being detected. Finally, we improve the protocol to be secure against all the present attacks.

In this paper, we study the cryptanalysis of two quantum blind signature schemes and one quantum proxy blind signature protocol. We show that in these protocols the verifier can forge the signature under known message attack. The attack strategies are described in detail respectively. This kind of problem deserves more research attention in the following related study. We further point out that the arbitrator should be involved in the procedure of any dispute and some discussions of these protocols are given.

We investigate the distinguishability of orthogonal multipartite entangled states in d-qudit system by restricted local operations and classical communication. According to these properties, we propose a standard (2, n)-threshold quantum secret sharing scheme (called LOCC-QSS scheme), which solves the open question in [Rahaman et al., Phys. Rev. A, 91, 022330 (2015)]. On the other hand, we find that all the existing (k, n)-threshold LOCC-QSS schemes are imperfect (or “ramp”), i.e., unauthorized groups can obtain some information about the shared secret. Furthermore, we present a (3, 4)-threshold LOCC-QSS scheme which is close to perfect.

Unextendible product bases (UPBs) play an important role in quantum information theory. However, very little is known about UPBs in Hilbert space of local dimension more than three. In this paper, we study the UPBs in qutrit-ququad system and find that there only exist six, seven and eight-state UPBs. We completely characterize the six-state and seven-state UPBs. For eight-state UPBs, seven classes of UPBs are found. As auxiliary results, we study the distinguishability of qutrit-ququad UPBs by separable measurements and find that there exists a UPB that cannot be distinguished.

Semi-device-independent randomness expansion is the protocol which can generate and certify perfect free random numbers, without making detailed assumptions on the internal working of quantum devices, except the bound on the dimension of the Hilbert space. The two-dimensional (2D) quantum witness violation has been used to generate guaranteed fresh randomness from untrusted devices in the prepare-and-measure configuration. In this paper we first show that the 2D quantum witness violation can be simulated by a classical deterministic process by relaxing the assumption of the dimension. A deterministic process to simulate the generation of random numbers is given, under the hidden variables model, with just the high dimensional measurement device and one qubit communication. This makes the generated number essentially deterministic, which is said to be pseudorandom. Then we also show that when we relax the freedom of choice, there is the exact region for which quantum correlations can be simulated by the classical process in the task of randomness expansion.

Objectives: Hypertension was the most important risk factor for ischemic stroke. In China, three fourths of treated hypertensive didn’t meet the standard of control. We analyzed the relationship between systolic blood pressure, diastolic blood pressure, pulse pressure and mean arterial pressure and Ischemic stroke in patients with uncontrolled hypertension. Methods: In this cross-sectional survey, subjects with uncontrolled hypertension aged above 35 years were recruited from the general medicine clinic of Beijing Anzhen Hospital and its affiliated community health centers from March to December 2012. Results: After adjusted for 7 covariates, each index was significantly correlated with ischemic stroke according to the result of single index model. SBP ≥ 150 mmHg, DBP ≥ 100 mmHg, high textile and quartile PP and high quartile MAP were associated with higher risk of ischemic stroke. When SBP and DBP or SBP and MAP were introduced into the model together, no significant difference was noted across categories of DBP and MAP, DBP and PP were introduced into the model together, no significant difference was noted across categories of DBP. Four indexes were introduced to the multifactorial model, only SBP entered into the model. Compared with SBP

Major and profound changes have taken place in China over the past 30 years. Rapid socioeconomic progress has exerted a great impact on lifestyle, ranging from food, clothing, working and living conditions, and means of transportation to leisure activities and entertainment. At the same time, new health problems have emerged, and health services are facing new challenges. Presently, cardiovascular diseases (CVD) are among the top health problems of the Chinese people, and pose a serious challenge to all engaged in the prevention and control of these diseases. An epidemic of CVD in China is emerging as a result of lifestyle changes, urbanization and longevity. Both national policy decision-making and medical practice urgently need an authoritative report which comprehensively reflects the trends in the epidemic of CVD and current preventive measures. Since 2005, guided by the Bureau of Disease Prevention of the Ministry of Health of the People's Republic of China and the National Center for Cardiovascular Diseases of China, nationwide experts in the fields of epidemiology, clinical medicine and health economics in the realms of CVD, cerebrovascular disease, diabetes and chronic kidney disease, completed the Report on Cardiovascular Diseases in China every year. The report aims to provide a timely review of the trend of the epidemic and to assess the progress of prevention and control of CVD. In addition, as the report is authoritative, representative and readable, it will become an information platform in the CVD field and an important reference book for government, academic institutes, medical organizations and clinical physicians. This publication is expected to play a positive role in the prevention and control of CVD in China. We present an abstract from the Report on Cardiovascular Diseases in China (2010), including trends in CVD, morbidity and mortality of major CVDs, up-to-date assessment of risk factors, as well as health resources for CVD, and a profile of medical expenditure, with the aim of providing evidence for decision-making in CVD prevention and control programs in China, and of delivering the most authoritative information on CVD prevention and control for all citizens.

To analyze the relationship between prevalence of metabolic syndrome (MS) and behavior habits such as smoking, alcohol intake, physical activity, sleeping hours.A multi-stage stratified cluster sampling was conducted in 31 provinces, autonomous regions, and municipalities in China according to the program of National Nutrition and Health Survey. Questionnaire survey, interview, physical examination, measurement of biochemical indices, and dietary investigation were done. In total, 4937 men aged 18 to 45 years old were selected.The MS prevalence was 6.9% (329/4937). The rate of drinking was 49.4% and smoking rate was 54.4%. The percentage of sleeping was hours from 7 to 8 was 70.5%. The percentage of spending time on physical activity over 420 minutes/week was as high as 41.9%. Data from single logistic regression showed volume of smoking more than 600 packs and alcohol intake were associated with high risk of MS and no significantly associations were found between MS and the duration of physical activity and the sleeping time. Multivariate logistic regression showed that the risk of MS in smokers with the volume more than 600 packs age increased significantly as compared to nonsmokers with the odds ratio as 1.443 (95%CI: 1.044 - 1.993) and 1.765 (95%CI: 1.150 - 2.708) in smokers with volume from 600 to 899 packs age, and more than 900 packs age respectively. Compared to the nondrinkers, the odds ratios were 1.525 (95%CI: 1.135 - 2.048), 2.322 (95%CI: 1.671 - 3.255) and 2.033 (95%CI: 1.478 - 2.796) in subjects volume of alcohol drinking as 1 to 2 times per week, 3 to 4 times per week and more than 5 times per week respectively.Tobacco and alcohol were associated with high risks of MS.

To analyze the relationship between low to moderate physical activity and the prevalence of metabolic syndrome (MS).A multi-stage stratified cluster sampling was conducted in 31 provinces, autonomous regions, and municipalities in the interior of China according to the program of the National Nutrition and Health Survey in 2002. Questionnaire survey, interview, physical examination, measurement of biochemical indices and dietary investigation were done. In total, the physical activity of 26 477 persons aged 18 or above were investigated. The duration of low to moderate physical activity was divided into five grades: 0-min/week, 90-min/week, 151-min/week, 301-min/week, over 420 min/week, and the MS prevalence were investigated respectively. The relationship between MS and age (including four age groups 18-, 35-, 45-, 60 or above) or the duration of physical time were investigated.The MS prevalence among persons aged 18 or above was 9.4% (2490/26 477). And the prevalence was 10.3% (1191/11 516) in man and 8.7%(1299/14 961) in women, respectively (χ(2) = 21.035, P = 0.000). The MS prevalence was 2.1% (127/6070) in 18-years old group and 15.0% (1012/6734) in over 60 years old group. The MS prevalence increased with increasing age (χ(2) = 776.768, P = 0.000). 81.2% (21 499/26 477) of subjects engaged in low to moderate intensity physical activity. The percentage of spending time on physical activity over 420 min/week was dominant and as high as 43.7% (11 561/26 477). The MS prevalence was 13.8% (166/1203) for 0-min grade, 13.2% (64/485) for 90-min grade, 11.8% (153/1298) for 151-min grade, 10.1% (124/1225) for 301-min grade and 12.5% (512/4090) for over 420 min grade (χ(2) = 9.58, P = 0.047). Logistic regression analysis results showed, the MS risk of subjects spending 301-min per week on low to moderate intensity physical activity was significantly low than the MS prevalence among subjects of 90-min grade, OR = 0.844 (95%CI: 0.675 - 0.968), and no statistical difference was found in people spending over 420 min per week OR = 0.936(95%CI: 0.769 - 1.136).Most of people aged 18 or above engaged in low to moderate intensity physical activity. MS prevalence may be decreased by low to moderate intensity physical activity for 301-min per week, but the decrease was not significant while the duration of time was longer than 420 min per week.

To analyze the level of exposure and cluster of risk factors to stroke for patients with non valvular atrial fibrillation.A questionnaire survey was conducted among 583 patients with non valvular atrial fibrillation, randomly selected from 8 general hospitals and 7 community health service centers located in the 8 districts in Beijing city in 2006.133 patients attacked stroke and the prevalence of stroke in the total 583 patients was 22.8%. 78 patients attacked stroke after being diagnosed as atrial fibrillation with the prevalence related to atrial fibrillation as 14.3%. The levels of exposure related to age, duration of atrial fibrillation, histories of hypertension, diabetes and dyslipidemia were significantly different between stroke and non-stroke patients (P0.05). Data from multiple variables logistic regression analysis showed that age, duration of atrial fibrillation, history of dyslipidemia and history of diabetes increased the risk of stroke with odds ratio as 1.06, 2.08, 1.82, 1.79 respectively (95%CI was not including 1). The risk of stroke among those having 3 or 4 risk factors was 4.36 and 4.51 times of those without risk factor after adjusting for age, sex and duration of atrial fibrillation.Age, duration of atrial fibrillation, history of dyslipidemia and history of diabetes were the main risk factors related to stroke and the clustering of risk factors would further increase the risk. It is important to control blood pressure, blood surge and lipid besides therapy of anticoagulation or antiplatelet for patients with nonvalvular atrial fibrillation.

To assess the anticoagulation treatment in real-life practice for nonvalvular atrial fibrillation (AF) in Beijing.A questionnaire survey was conducted among 583 patients with nonvalvular AFF, 327 males and 256 females, aged 40 - 93, selected randomly from 8 general hospitals (n = 375, 64.3%) and 7 community health service centers (n = 208, 35.7%) located in the 8 districts in Beijing city, mainly from the out-patient departments (n = 437, 75%).110 of the 583 patients (18.9%) were prescribed warfarin in which the percentage of international normalized ratio (INR) range (2.0 - 3.0) was 39.1% (n = 43). 68.2% of them had taken warfarin for less than one year. Another 33 patients (5.7%) had ever taken warfarin. 346 patients (59.3%) took aspirin of which 85.7% were exposed to the dose of 76 - 150 mg/d, and no one was administered the dose of 325 mg/d. 18.9% of the 583 patients had not received any anticoagulation or antiplatelet drugs. 78.6% of patients had never got the advice about taking warfarin from their doctors, and over 75% of the patients lacked in knowledge about the necessity of anticoagulation treatment for AF patients. The prevalence of stroke in the total 583 patients was 22.8%, 22.0% in those receiving warfarin treatment, 24.3% in those receiving aspirin treatment, and 21.3% in those receiving neither anticoagulation treatment nor antiplatelet treatment, without significant differences among them (chi(2) = 1.09, P = 0.58).The percentage of taking anticoagulation treatment in real-life practice pf the AF patients in Beijing is lower than that of taking antiplatelet treatment. The period of anticoagulation treatment is short and the effect is not good. The percentage of taking aspirin is too high in the high risk patients of stroke, but the dose of aspirin is on the low side. Doctors' advice and knowledge related to anticoagulation treatment of the patients are important factors influencing the anticoagulation treatment.

To study hypertension control, follow up and the factors associated with the rate of hypertension control.Through a community-based study, the routine data were collected through a community hypertension managing software for one year.There were 3375 hypertension patients above 60 years old recruited in the information system. In the baseline, the rate of blood pressure control was 63.5%, and arranging intervals up to 6 months was 66.9%. Hypertension control rate for the baseline, the third month and the sixth month was 61.8%, 62.4% and 61.6%, respectively (chi2 = 0.16, P = 0.69). Among hypertensives whose blood pressure was stabilized in baseline, hypertension control rates for the third month and the sixth month was 72.9.8% and 72.1%, respectively (chi2 = 0.26, P = 0.61). Blood pressure stabilized over 6 months in comparing with others, and the proportion for regular taking medication was 96.2% and 97.7% (chi2 = 3.58, P = 0.06). The proportion for physical activity, less salt intake, weight control was significantly higher in the patients whose blood pressure control well over 6 month.Rate of blood pressure control among elderly patient with hypertension who frequently consults the doctor in the community is high. Ineffectiveness in systolic and diabetes control is the important factor, which decreases the rate of blood pressure. Physical activity, less salt intake, and weight control are of help to hypertension control. For those, the blood pressure are stabilized, a follow up with 3 to 6 months interval is appropriate.

To investigate the relationship between physical activity and metabolic syndrome (MS).A multi-stage stratified cluster sampling was conducted in 132 sampling 218,920 residents, aged 44.3 +/- 15.3 (15 - 96), in the 31 provinces, autonomous regions, and municipalities of the mainland China according to the program of the National Nutrition and Health Survey. Questionnaire survey, interview, physical examination, measurement of biochemical indices, and dietary investigation were done. Information of physical activity and measurement of fasting glucose and/or glucose 2 hours after meal, blood pressure, triglycerides, high-density lipoprotein cholesterol were obtained in 50,494 participants. Metabolic syndrome was defined according to the Chinese Medical Association's definition. The intensity of physical activity was divided into 3 categories according to the Center for Disease Control and Prevention of US/American College of Sports Medicine criteria.50,495 subjects, 23,932 males (47.4%) and 26,562 females (52.6%), were diagnosed as with MS. The MS incidence of those with high intensity of physical activity was lower by 60% in comparison with those with low intensity of physical activity (odds ratio 0.60, 95% CI: 0.362 - 0.443) adjusted for age, sex, smoking, and alcohol intake. The risk of MS in those with moderate intensity of physical activity of 151 - 300 minutes/week was slightly decreased compared to those with moderate intensity of physical activity of 90 - 150 minutes/week, (odds ratio 0.935, 95% CI: 0.685 - 1.277), however, the risk of MS in those with the moderate intensity of physical activity over 300 minutes/week increased slightly (OR = 1.269, 95% CI: 0.923 - 1.745). The risk of MS in those with low-level physical activity of 301 - 420 minutes/week was lower by 35% in comparison with those with the low-level physical activity of 90 - 150 minutes/week (95% CI: 0.451 - 0.933), however, the risk of MS in those with the low-level physical activity over 420 minutes/week was 0.871, not significantly different from that of the subjects with the low-level physical activity of other intensity (odd ratio = 0.871, 95% CI: 0.643 - 1.181). The risk of MS of those with the vigorous physical activity odds rations for having MS of vigorous activity over 150 minutes/week was 0.757, lower by 25% in comparison with those with the vigorous physical activity of 10 - 60 minutes/week (95% CI: 0.603 - 0.951), adjusted for sex, age, smoking, alcohol intake and BMI.MS risk can be decreased by low level physical activity of 300 - 420 minutes/week, moderate physical activity of 90 - 300 minutes/week and vigorous physical activity of over 150 minutes/week.

To analyze the therapy of hypertensive outpatients among different grade hospitals in Beijing.Thirty-nine hospitals including 4 third grade hospitals, 4 second grade hospitals and 31 first grade hospitals in Beijing were selected randomly (by stratified randomization). The grade was accredited according to the hospital accreditation standard issued by Ministry of Health of the People's Republic of China.The average hypertension control rate (140/90 mm Hg, 1 mm Hg = 0.133 kPa) in outpatients was 32.3%. The hypertension control rate in the third grade, second grade, first grade hospitals were 37.7%, 36.9%, and 31.2% respectively. There was no difference in the control rate among the three different grade hospitals (P0.05). The frequency to use anti-hypertension drugs including long-acting calcium antagonism, ACEI, beta-receptor blocker in the third grade hospitals was significantly higher than those of the first and second grade hospitals. The rate of examination using ultrasonic cardiogram, CT, Holter and ambulatory blood pressure monitoring were significantly higher in the third grade hospitals than that of the first and second grade hospitals. There were significant differences in annual cost of hypertension treatment among three different grade hospitals (P0.01), being the highest (1567.5 yuan) in the third grade hospitals, medium (845.4 yuan) in the second grade hospitals, the lowest (651.8 yuan) in the first grade hospitals.Significant difference in the cost of hypertensive treatment among three different grade hospitals exists in Beijing. However, there was no difference in the control rate among them. The overall hypertension control rate is 32.3%, leaving 67.7% uncontrolled. Efforts to increase the hypertension control rate should be made in all hospitals. How to guide and arrange the hypertension patients to consult a suitable hospital is important for rational and economical use of health cost.

To study the relationship between blood pressure control status and patients' knowledge on hypertension prevention and control among hypertensive patients.A total of 726 hypertensives were selected from four community health service centers (2 urban and 2 rural) in Beijing. All subjects were investigated by questionnaires and their blood pressures were measured at the same time.The rate for blood pressure under control (140/90 mm Hg, 1 mm Hg = 0.133 kPa) in the rural and urban patients were 46.4% and 23.9% respectively. The control rate increased with the increase of patients' knowledge on prevention and control of hypertension in both urban and rural patients. The cumulative effect of knowledge on hypertension control status could contribute 30.0% to the difference in hypertension control rate between rural and urban patients.Patients' knowledge on hypertension control was significantly related to the rate on hypertension control. Health education should be helpful to improve the rate on hypertension control.

An arbitrated quantum signature scheme, which is mainly applied in electronic-payment systems, is proposed and investigated. The ?-type entangled states are used for quantum key distribution and quantum signature in this protocol. Compared with previous quantum signature schemes which also utilize ?-type entangled states, the proposed scheme provides higher efficiency. Finally, we also analyze its security under various kinds of attacks.

Recently, Yin et al. (Int. J. Quantum Inform. 10 (2012) 1250041) proposed a quantum proxy group signature scheme with χ-type entangled states. The scheme combines the properties of group signature and proxy signature. The study points out that the semi-honest Trent can give the forged signature under the assumption of this scheme. And, we find that even if the three parties honestly perform the scheme, the signature still cannot be realized with high efficiency.

In this paper, we propose a new secure quantum group signature with Bell states, which may have applications in e-payment system, e-government, e-business, etc. Compared with the recent quantum group signature protocols, our scheme is focused on the most general situation in practice, i.e. only the arbitrator is trusted and no intermediate information needs to be stored in the signing phase to ensure the security. Furthermore, our scheme has achieved all the characteristics of group signature—anonymity, verifiability, traceability, unforgetability and undeniability, by using some current developed quantum and classical technologies. Finally, a feasible security analysis model for quantum group signature is presented.