关于素数定理的构成图

用“常因数”图（构成图）论述著名素数定理的构成问题，因构成图的深刻性和直观性，使素数定理变得明了和通俗．

Irritable bowel syndrome:Diagnosis and pathogenesis

Irritable bowel syndrome (IBS) is a common gastro-intestinal (GI) disorder that considerably reduces the quality of life. It further represents an economic burden on society due to the high consumption of healthcare resources and the non-productivity of IBS patients. The diagnosis of IBS is based on symptom assessment and the Rome Ⅲ criteria. A combination of the Rome Ⅲ criteria, a physical examination, blood tests, gastros-copy and colonoscopy with biopsies is believed to be necessary for diagnosis. Duodenal chromogranin A cell density is a promising biomarker for the diagnosis of IBS. The pathogenesis of IBS seems to be multifactorial, with the following factors playing a central role in the pathogenesis of IBS:heritability and genetics, dietary/intestinal microbiota, low-grade inflammation, and disturbances in the neuroendocrine system (NES) of the gut. One hypothesis proposes that the cause of IBS is an altered NES, which would cause abnormal GI motility, secretions and sensation. All of these abnormalities are characteristic of IBS. Alterations in the NES could be the result of one or more of the following:genetic factors, dietary intake, intestinal flora, or lowgrade inflammation. Post-infectious IBS (PI-IBS) and inflammatory bowel disease-associated IBS (IBD-IBS) represent a considerable subset of IBS cases. Patients with PI-and IBD-IBS exhibit low-grade mucosal inflammation, as well as abnormalities in the NES of the gut.

Atrial fibrillation in the elderly

Atrial fibrillation （AF） is the most frequent arrhythmia. Due to population aging, AF is a growing epidemic and its importance will continue to increase in the next decades. Although the prevalence of AF is high in advanced age, the number of subjects with predisposing factors for AF is even higher. Most of these factors increase the risk of atrial fibro- sis, an important component of atrial arrhythmia mecha- nisms. In fact, the new techniques to detect atrial fibrosis are showing the strong association between atrial fibrosis and AF risk. Regarding predisposing factors for AF, interatrial block （LAB） seems to be a key factor.

Henry's Law constant for phosphine in seawater:determination and assessment of influencing factors

The Henry＇s Law constant （k） for phosphine in seawater was determined by multiple phase equilibration combined with headspace gas chromatography. The effects of pH, temperature, and salinity on k were studied. The k value for phosphine in natural seawater was 6.415 at room temperature （approximately 23℃）. This value increases with increases in temperature and salinity, but no obvious change was observed at different pH levels. At the same temperature, there was no significant difference between the k for phosphine in natural seawater and that in artificial seawater. This implies that temperature and salinity are major determining factors for k in marine environment. Double linear regression with Henry＇s Law constants for phosphine as a function of temperature and salinity confirmed our observations. These results provide a basis for the measurement of trace phosphine concentrations in seawater, and will be helpful for future research on the status of phosphine in the oceanic biogeochemical cycle of phosphorus.

Prevalence of Abnormity of Blood Lipid and Associated Factors in Health Examination Population in Beijing

Objective To investigate the prevalence of abnormity of blood lipid and associated factors in healthy population in Beijing. Methods Totally, 38 462 individuals who received health examination were enrolled in our study. We divided them into eight groups according to their ages. The levels of serum total cholesterol, triglyceride, high density lipoprotein cholesterol, and low density lipoprotein cholesterol were tested, and the relationship of blood lipid abnormity with body mass index (BMI) and fasting blood glucose was analyzed. Results The incidences of hypercholesterolemia, hyperglyceridemia, low high-density lipoprotein cholesterolemia, and hyper low-density lipoprotein cholesterolemia presented increasing trend in this population. The incidence rate of abnormity of blood lipid in health examination population increased with BMI increase. The incidence of abnormity of blood lipid in overweight and obesity population was significantly higher than that in low weight and normal weight populations (P<0.05). Meanwhile, the trend of abnormal blood lipid incidence coincided with that of abnormal fasting blood glucose. Conclusions The prevalence of overweight, obesity, and abnormity of blood lipid in Beijing presents increasing trend. The incidence of abnormity of blood lipid increases with BMI increase, in coincidence with that of fasting blood glucose.

Thermal Response Test by Improved Test Rig with Heating or Cooling Soil

An improved test rig providing both the heat and cold source was used to perform thermal response test （TRT）, and the line source model was used for data analysis. The principle of determining the temperature difference between the inlet and outlet of test well can keep the heating or cooling rate constant, along with a reduced size of test rig. Among the influencial factors of the line source model, the temperature difference was determined as the most important, which agreed with the test results. When the gravel was taken as the backfill material, the soil thermal conductivities of heating and cooling at the test place were 1.883 W/（m＆#183;K） and 1.754 W/（m＆#183;K）, respectively, and the deviation of TRT between heating and cooling soil was 6.8%. In the case of fine sand, the thermal conductivities of heating and cooling were 1.541 W/（m＆#183;K） and 1.486 W/（m＆#183;K）, respectively, and the corresponding deviation was 6%. It was also concluded that different velocities of water had less influence on TRT than the temperature difference.

Normal Reference Value of Red Blood Cell Count of Chinese Presenile Men and Geographical Factors

This paper aims at providing a scientific basis for unifying the normal reference value standards of red blood cell count of Chinese presenile men. The paper, using microscopical counting method, studies the relationship between the normal reference values of 38,061 samples of red blood cell count of presenile men and eight geographical factors in 297 units in China. It is found that the correlation of geographical factors and the normal reference value of red blood cell count of presenile men is quite significant （F=303.00, P=-0.000）. By using the method of stepwise regression analysis, one regression equation is inferred. It is concluded that if geographical data are obtained in a certain area, the normal reference value of red blood cell count of presenile men in this area can be reckoned by using the regression analysis. Furthermore, according to the geographical factors, China can be divided into eight regions： Northeast China Region, North China Region, Shanxi-Shaanxi-Irmer Mongolia Region, Middle and Lower Reaches of the Changjiang River Region, Southeast China Region, Northwest China Region, Southwest China Region and Qinghai-Tibet Plateau Region.

Atrial fibrillation： the current epidemic

Atrial fibrillation （AF） is the most common arrhythmia diagnosed in clinical practice. The consequences of AF have been clearly estab- lished in multiple large observational cohort studies and include increased stroke and systemic embolism rates if no oral anticoagulation is prescribed, with increased morbidity and mortality. With the worldwide aging of the population characterized by a large influx of ＂baby boomers＂ with or without risk factors for developing AF, an epidemic is forecasted within the next 10 to 20 years. Although not all studies support this evidence, it is clear that AF is on the rise and a significant amount of health resources are invested in detecting and managing AF This review focuses on the worldwide burden of AF and reviews global health strategies focused on improving detection, prevention and risk stratification of AF, recently recommended by the World Heart Federation.

A National Cross-Sectio nal Survey Dataset on Com mon Disease and Influencing Factors of Chinese Internal Migrants in 2017

This data article describes the dataset from a national cross-sectional questionnaire survey on Chinese internal migrants in 2017.The survey was part of the Chinese Migrants Dynamic Survey,which is an annually conducted large-scale national questionnaire survey on internal migrants.The respondents in the described dataset were migrants and registered local residents aged over 15 years old.A multistage stratified probability-proportionalto-size(PPS) sampling method based on the 2016 annual report data of China Migrant Population was adopted.The questionnaire was designed to collect demographic information of respondents and their family members,intention of migration or settlement,health status,health services accessibility,social integration,and epidemic influencing factors of common diseases,including hypertension,type 2 diabetes,diarrhea,fever,rash,icterus,conjunctival redness,cold,and other illnesses or injuries.The sample population in this survey include 13,998 internal migrants and 14,000 registered local residents from eight domestic cities/prefecture/districts across China.It is the most widely covering and highly representative dataset on common diseases and influencing factors of internal migrants in China.The dataset can be used to study common diseases and influencing factors among floating Chinese population.It provides data support for government to improve healthcare accessibility and the equity of public health services for internal migrants in China.

Role of ATG16L,NOD2 and IL23R in Crohn's disease pathogenesis

Inflammatory bowel disease is a group of diseases that includes Crohn＇s disease （CD） and ulcerative colitis. CD is characterized as a chronic inflammatory disease of the gastrointestinal tract, ranging from the mouth to the anus. Although there are gross pathological and histological similarities between CD and Johne＇s dis- ease of cattle, the cause of CD remains controversial. It is vital to understand fully the cause of this disease because it affects approximately 500 000 people in North America and Europe. It ranges from 27 to 48 cases per 100 000 people. There are many theories on the cause of CD ranging from possible association with environmental factors including microorganisms to imbalance in the intestinal normal flora of the pa- tients. Regardless of the environmental trigger, there is strong evidence that a genetic disposition is a major key in acquiring CD. Many studies have proven the link between mutations in the ATG16L, NOD2/CARD15, IBDS, CTLA4, TNFSF15 and IL23R genes, and CD. The purpose of this review is to examine all genetic aspects and theories of CD, including up to date multiple popu- lation studies performed worldwide.

A COMPLETE SCREEN FOR MUTATIONS OF THE RHODOPSIN GENE IN A PANEL OF CHINESE PATIENTS WITH AUTOSOMAL DOMINANT RETINITIS PIGMENTOSA

Objective To evaluate the prevalence of rhodopsin (RHO) mutations and the genotype-phenotype relationships in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) by conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing. Methods We have screened the five coding exons and splice sites of RHO gene in 27 probands who had no relativity from Chinese ADRP families and 100 normal controls to identify disease-associated mutations, using CSGE and direct DNA sequencing. Family members of some probands with disease-associated mutations were also genotyped to determine whether the RHO mutations segregated with retinitis pigmentosa (RP) in their families. Results Two RHO mutations, Pro347Leu and Pro327 (1-bp del), were identified separately in two families, thus the frequency of RHO mutations among this set of Chinese ADRP families is about 7.4% (2/27). Pro347Leu mutation was found in one ADRP proband as well as three her children who also had RP. She had relatively early onset at about 17 years. The only one child without this mutation had no symptom or sign of RP at age of 34. Pro327 (1-bp del) was identified in a late-onset ADRP patient, who appeared night blindness around 30 years old and in her fifties electroretinogram (ERG) has been flat in both scotopic and photopic phases. Family analysis showed that this mutation also existed in her younger dau-ghter and her elder sister, both of them also had RP. Three other family members were genotypically and phenotypically normal. Neither of the two mutations was detected in 100 normal controls.Conclusions The frequency of RHO mutations in Chinese patients was lower than that in Europe and North America. The phenotype of the patients with Pro347Leu corresponded to type 1 ADRP, with severe rod degeneration and some cone preservation later, while the phenotype of the patients carrying Pro327 (1-bp del) corresponded to type 2 ADRP, with a concomitant loss of rod and cone visual function. CSGE was found to be a sensitive, simple, and practical method for the screening of a large number of samples under highly reproducible conditions, and could be utilized in routine molecular diagnostic laboratories.

Skulls Symmetry of ＂White Rasquera＂ Goat

Three common categories of bilateral asymmetry have been described： directional asymmetry, antisymmetry, and FA （fluctuating asymmetry）. FA is the most subtle of the three types of asymmetry, and differs from the patterns of the others in that paired structures tend to be symmetric in size. The analysis of FA allows to estimate the influence of stress factors on animal development and enables evaluation of resistance to stress. The aim of this work was to estimate the symmetry of skulls of a contemporary pure goat breed, as there is currently no study of FA as an estimate of individual quality for domestic goats. For this purpose, 11 landmarks were digitized in two dimensions from the crania of 24 adult goats （12 males and 12 females） belonging to the ＂White Rasquera＂ breed. The skulls showed nearly perfect bilateral symmetry. The low detected values of FA in skulls revealed a weak influence of developmental stress on this goat contemporary population and its strong ability to compensate stress.

Hierarchical Linear Model Approach to the Determinants of Activities of Daily Living of Chinese Oldest Old at Both Individual and Regional levels

Based on the Chinese longitudinal healthy longevity survey conducted in 2002, this paper uses hierarchical linear model (HLM) to make an approach to the possible determinants of activities of daily living (ADL) of Chinese oldest old (aged 80 and above) by combining both individual and provincial level factors. The descriptive analysis shows that there is a great differ- ential in ADL by province among Chinese oldest old. The findings turn out that there does exist a significant differential in ADL between oldest old and young old, and that there is also a great differential in ADL by province among Chinese oldest old. The HLM demonstrates that comorbidity, age, cognitive impairment, visual impairment, and emotion could be the most important indi- vidual factors while natural environment, medical facilities, type of staple food and poverty rate in urban areas are the most sig- nificantly regional determinants of ADL of oldest old. The find- ings imply that future actions should not only be taken at individ- ual level, but also at regional level in order to achieve the goal of a healthy aging society in China.

Pressure fluctuation and its influencing factors in circulating water pump

In order to investigate the effect of sampling frequency and time on pressure fluctuations, the three-dimensional unsteady numerical simulations were conducted in a circulating water pump. Through comparison of turbulence models with hydraulic performance experiment, SST k-co model was confirmed to study the rational determination of sampling frequency and time better. The Fast Fourier Transform （FFT） technology was then adopted to process those fluctuating pressure signals obtained. On these bases, the characteristics of pressure fluctuations acting on the tongue were discussed. It is found that aliasing errors decrease at higher sampling frequency of 17 640 Hz, but not at a lower sampling frequency of 1 764 Hz. Correspondingly, an output frequency range ten-times wider is obtained at 17 640 Hz. Compared with 8R, when the sampling time is shorter, the amplitudes may be overvalued, and the frequencies and amplitudes of low-frequency fluctuations can not be well predicted. The frequencies at the tongue are in good agreement with the values calculated by formula and the frequency compositions less than the blade passing frequency are accurately predicted.

Morphometric Data of Testudo hermanni in the Vlora Area

The purpose of this paper is the morphometric study as well as the assessment of population structure of the Testudo hermani tortoise in the Vlora area. Individuals are collected in the study area. A morphometric study is made for the caught individuals. Suitable habitats have been identified for their growth and development. It is estimated the number of healthy or unhealthy individuals, dead individuals and also the identification of the local population＇s threatening factors. Individuals with anomalies are studied and then compared with normal individuals, especially in terms of the number and shape of the dermal plates.

Analysis of related factors affecting prognosis of shunt surgery in patients with secondary normal pressure hy- drocephalus

Objective： The management of se- condary normal pressure hydrocephalus （sNPH） is controversial. Many factors may affect the surgery effect. The purpose of this study was to identify the possible fac- tors influencing prognosis and provide theoretical basis for clinical treatment of sNPH. Methods： A retrospective study was carried out to investigate the results of 31 patients with sNPH who under- went ventriculoperitoneal shunt surgery from January 2007 to December 2011. We processed the potential influencing factors by univariate analysis and the result further by mul- tivariate logistic regression analysis. Results： Factors including age, disease duration and Glasgow coma scale （GCS） score before surgery significantly influenced the prognosis of sNPH （P〈0.05）. Further logistic regression analysis showed that all the three factors are independent influencing factors. Conclusion： Age, disease duration and GCS score before surgery have positive predictive value in estimating favorable response to surgical treatment for sNPH.